Section 1: Compile and Refine the Data

Just like the jigsaw puzzle analogy, the best place to start is by assembling the obvious pieces like the border. For the trail concept plan, this equates to examining the constraints and eliminating the “no-go” zones, marking out the “partial-go” zones, and identifying the “don’t-want-to-go” zones. A query of the GIS resource layers should quickly identify polygons for these three zones.

Control Points

Control points are features that have a direct influence on where a trail goes. There are two types of controls: a place where riders have to be (positive control point), and a place where riders can’t be (negative control point). The planners’ first trips to the project area should focus on identifying control points. The more of these that are found early on, the more solid the trail concept plan will be. When an impassable ravine or other feature not previously identified is found, the process can come to a halt. The feature needs to be added to the concept plan and the trail corridors adjusted accordingly. Sometimes these adjustments can significantly alter the concept plan, and that consumes time and project dollars.

Some common positive control points are trail termini, road and creek crossings, points of interest, etc.

Termini of the Trail. Certainly, the first thing planners need to know is where a trail starts and ends. Does it start at the trailhead, staging area, campground, or someplace else? With existing facilities, sometimes the termini are obvious, but if the project area is a clean slate, the first order of business is to determine where the trailheads, campgrounds, or other facilities will be located. Depending on the site, this task can be a challenge.

Road Crossings. First of all, is it legal to cross the road? If it is legal, where are the crossing locations that have flat approach grades and adequate sight distance given the speed of the traffic on the road. Some road crossings may require a permit from the road authority. If so, these should be obtained early in the planning process.

Points of Interest. Planners should identify unique features, interpretive points, and naturally occuring features which add interest and seat time to the riders’ experience.

Creek Crossings. Every agency and area has different criteria for stream crossings, especially if it is a fish-bearing stream or a tributary to a community water source. The first thing planners need to do is determine the classification for the stream and any associated agency, state, federal, or provincial laws or regulations. As with roads, some streams may require a permit with seasonal constraints to work in the stream.

The best practice for crossing perennial streams is to avoid tire contact with the water. This offers the most protection for the stream and the environment by minimizing the risk of sedimentation. This involves the installation of a bridge, culvert, or in low flow streams, well-placed cobble rock to keep the tires out of the water.

If it is legal and appropriate to cross the stream on-grade with a ford, a qualified person must determine where the crossing points are that have good approach grades, a narrow riparian corridor, and the lowest stream flow. These ford crossing points become control points.

Where bridges are required, proper bridge sites also become control points. These are sites where there are stable banks for the bridge abutments to set; where the stream is down in a channel so there is a good elevation drop from the top of the bank down to the stream level; where the stream flow is straight to minimize scouring of the banks; and where the bridge span will be the shortest possible. Planners can find these sites, but usually an engineer will be required to assess the site and perform any necessary engineering surveys.

Saddles. These are a break or the lowest points in a ridge line. Some regions refer to them as gaps or notches. If a trail needs to cross a ridge, a saddle will require the least elevation gain and loss. In very rugged, technical terrain, the saddle may be the only place to cross the ridge line.

Existing Road Infrastructure. When it comes to major stream crossings with bridges, major culverts, or pipe arches, it can be a good strategy to try to utilize existing road infrastructure for these crossings. Not only does it save project dollars, it can reduce potential environmental impacts. Contact the road authority and obtain any necessary permits. There will need to be additional signing for mixed use and that should be addressed in the sign plan.

Some common negative control points are impassable, unstable, or undesirable terrain and prohibited or restricted areas.

Impassable Terrain. These controls could be cliffs; deep, heavily eroded ravines or gullies; lakes and ponds; or fault lines.

Unstable Terrain. These could be landslides, slumps, avalanche chutes, or any area with steep ground and unstable soils. On slopes of more than 30 percent, avoid areas that have a shallow lens of soil on top of slab rock. A terrain stability map can help identify these areas, though often they need to be ground-truthed for accuracy.

Undesirable Terrain. Wet areas fall into this category as well as those areas that will be wet like flood plains. While rock rubble fields like scree can create a beautiful and technically challenging trail, they can be high maintenance because rock is constantly sloughing off into the trail—the wider the tread, the bigger the issue. If the trail is to be wide and of low difficulty, scree becomes a negative control point.

Examine the Constraints

Prohibited Areas. What are the areas where a trail can’t be put? These areas are usually dictated by resource management rather than by the physical characteristics of the site. As no-go zones, they become negative control points. Examples of these areas are rare or sensitive vegetation areas, bald eagle management areas (BEMAs), areas of critical environmental concern (ACECs), and community water intakes or water reservoirs.

Cultural resource sites usually fall into the no-go category; however, if they are subsurface, sometimes they can be crossed if they are mitigated by trail hardening or by additional monitoring of the tread depth. Seek and follow the recommendations of the archaeologist.

Private property boundaries and agency boundaries are generally no-go areas unless agreements are in place to cross into areas of other ownership. The lease or tenure boundaries for active mineral extraction are generally no-go areas depending on how firm the project area boundary is.

Restricted Areas. Bird nest sites, especially those of TES species or indicator species, are often restricted. A trail can’t go under the nest, but it can go a specified distance away from the nest. Planners should find out the restricted area for that particular species and draw a circle around each known nest site. These partial-go zones also become negative control points. Rattlesnake dens or other dens may have similar protection. Some cave entrances, particularly those with sensitive bats, may be restricted. Water features like wells, springs, and water troughs often have a restricted area around them.

Some areas like deer or elk winter range may have seasonal restrictions such as winter closures. The requirements, if any, change by agency, state, or province. Planners should take the time upfront to identify these areas. It will make the plan more solid and environmentally defensible.

Riparian areas are often restricted. Trails can often cross them at 90 degrees to minimize impact, but they usually can’t meander through them. The number of crossings may also be restricted. In some cases, trails through riparian areas need to be elevated or hardened. Some jurisdictions may require a permit to cross riparian areas.

Big game connectivity corridors are often restricted. Like riparian areas, a trail can usually cross them at 90 degrees, but not meander through them. Often there is a buffer zone around private property. Some reservoirs, especially those associated with community water intakes, also may have a buffer zone.

Undesirable Ground. Each project has areas where there could be trails, but it’s not desirable to have trails. The first is flat ground. Flat ground? Isn’t it cheaper to build a trail on flat ground? Actually, no. A trail on flat ground can become a trench over time making it difficult to drain water off the trail. Flat ground can hold water that saturates the soil and creates mudholes. It is also more difficult to maintain the designed tread width on flat ground since riders will push out the edges to pass or to get around standing water that can’t drain. This results in trail braiding and widened trails.

Closely associated with flat ground are wet areas: riparian areas, bogs, wetlands, springs, or any area where the water table is at or close to the ground surface. These areas have saturated soils and are rich in flora and fauna diversity. It is best to avoid them. Wet areas are certainly red flag areas and usually become negative control points.

Large, open grassy, or sparsely vegetated areas go on this list also. Unless there is some topography or rocks, it is difficult to maintain the integrity of a serpentine alignment in these areas since riders can see the next curve and cut cross-country to intercept it. The alignment eventually becomes braided and straight. Unless natural or manmade barriers are used to protect the alignment, the designers are forced to flag in a very lazy S that is close to straight. This increases speed, increases impacts, and decreases seat time.

Depending on the type of riding, open areas can also be an issue. Any area that may have speed events should not have a large amount of trail in an area where sights are visible for long distances. The riders will cut the trails in order to gain position. This will result in trail braiding and straighter trails.

The more difficult the machine is to turn, the less likely a serpentine trail in an open area will stay intact. However, an OHV trail with a tight set of curves creates a technical challenge.

Trails through meadows fall into this category, but trails through recently harvested cut blocks or through recent burns do not. The natural environment is dynamic, not static, so change is a given. The planners and designers must visualize how a denuded area will look in 2 years, 5 years, and 15 years. Depending on the growing environment, the pace of recovery can be amazingly dramatic.

Once again, avoid fall line trails. They generally have sustained (long, unbroken) grades and poor drainage so water is typically channeled down the trail. It usually requires manmade structures to provide drainage, and these are costly and difficult to construct correctly, expensive to maintain, decrease the rider experience, and can fail in a significant weather event. Sometimes in technical terrain with tightly spaced controls on each side, the only option is to use the fall line. In these cases, mitigations like more drainage structures, trail hardening, or increased maintenance frequency are required.

Ridgetop trails can also be undesirable. If the slope of the ridgeline is uniform with a long and sustained grade, these trails become fall line trails. The sight line is often long on these trails and this tends to increase rider speed and decrease rider experience. The better alternative is to design a trail that serpentines up and crosses from one side of the ridge to the other. This breaks up the sight line and increases the trail aesthetics, creates positive drainage, and increases the rider experience by constantly changing the viewshed of the rider.

Examine the Opportunities

This next phase is the fun part. It’s time for the planners and designers to look at desirable terrain.

The ideal ground has a 15 to 45 percent sideslope with deep, stable soil and vegetative cover. Trees are preferred over brush, brush over grass, grass over a barren slope. Patches of thick trees or brush allow the designers to lay in a tight, technical serpentine alignment that slows down the riders, adds seat time, adds difficulty, and adds trail distance. Dense vegetation helps control tread width and protects the integrity of the alignment by deterring short-cutting of the curves.

A challenge for the planners and designers is to provide technical difficulty for the riders and still have a durable trail. For ultimate durability, look for rocks: boulder fields, rock gardens, solid slab rock that is on a slope, rimrock, slickrock, rock ledges or stepups, and hummocky broken ground. Rock provides opportunities for challenging trails while still maintaining durability.

Broken, uneven sideslopes with benches provide terrain diversity that gives the designers opportunities to reduce grade to provide drainage and flatter areas to change direction with a climbing turn. Terrain diversity also adds to the rider experience.

Desirable features include dramatic, unusual, or subtle features like rock formations; topographic edges like cliffs and rimrock; vegetative edges like the edges of meadows, cutblocks, and burns; old-growth forest; unique vegetation (twisted character trees, fields of wildflowers, tiny patches of moss or lichens, etc.); and vegetative changes such as moving from open to dense vegetation.

Rimrocks may be impassable terrain, but being on top of them is WOW terrain; a feature that will create a memorable experience.

Understand the Human Element

Where do riders (or any recreationists) want to go?

• The Highest Point. It is human nature to get to the highest point of land, not only for the view but also for the sense of achievement.
• Water. Lakes, ponds, creeks, springs, waterfalls are a natural attaction.
• Viewpoints. Whether it’s the highest point of land or just a break in the trees, people love scenic views of the landscape.
• Historic and Interpretive Sites. Riders enjoy seeing old mines, cabins, ghost towns, abandoned equipment, mills, etc. Those along with any interpretation of the natural environment enhances the riders’ experience.
• Wildlife Viewing. Riders of all ages enjoy seeing wildlife, including deer, elk, turkeys, bears, beavers, raptors, wild horses, and even snakes.
• Food. There is something about getting a burger on the trail that is very appealing to most riders. Food is a natural human attraction.

What do all of these six items have in common? They all provide a destination, a goal for the ride; they all provide photo opportunities; they all extend the time the riders are on the trail; they all provide an opportunity for riders to socialize with their group, which is an important element in OHV recreation; and they all add to the quality of the recreation experience. Around the campfire at the end of the day, these will be the highlights that everyone will talk about. These are the places that riders want to go. If at all possible, the planners should get them there.

Why? From a quality recreation and an effective OHV management standpoint, planners should always try to work with human nature rather than against it. The trail should take people where they want to go. It’s the WOW factor; that is what riders should say at the end of the trail. Planners should strive to find the WOW points and put them on the inventory and into the trail concept plan.

Riders’ needs and desires:

• Fun, fun, and more fun. People recreate to have fun.
• Connect with nature. Find our roots and a simpler existence.
• Escape from society
• Relieve stress
• Physical exertion and exercise
• Challenge for their vehicles and themselves
• A variety of experiences and difficulty levels
• Build camaraderie with friends and family engaged in the same activity
• A sense of belonging to a group
• A legal place to ride and feel welcome
• Enjoy quality facilities: kiosks, toilets, camping, etc.
• Enjoy quality trails, signing, and mapping
• Access to water features, scenic viewpoints, and unique features
• The opportunity to view wildlife

Section 2: Assemble the Data into a Trail Concept Plan

Now that the data has been gathered, it’s time to organize and manipulate that data so it can start making sense. The inventory data will be displayed as a maze of points, lines, and polygons. To make sense of them, planners and designers should assign colors or other attributes to the data and then organize it into groups. Groups could be roads, trails, resource data, water features, opportunities, and constraints. This is what a typical inventory could look like with trails and roads as lines and resource concerns as shapes.

Examine the Trail Inventory

Planners should first look at the trail data and eliminate the obvious. Look at the trails that lead into the no-go or restricted zones. If the assumption is made that all of the resource areas of concern require avoidance, then the trails leading into those areas would be slated for closure in the trail concept plan.

Next, planners should look at the trail inventory and data dictionary information and identify:
a) which trails or sections of trail are sustainable and provide a quality recreation experience;
b) which trails or sections of trail need some relocation or reconstruction to become sustainable and provide a quality experience; and
c) which trails or sections of trail are non-sustainable, cannot be made sustainable, or do not provide a quality experience.

Those trails in “a” and “b” will remain on the trail concept plan for the time being. Those trails in “c” will be slated for closure. Sometimes, there isn’t enough information in the inventory to make these determinations at this time, but often the planners can make subjective assumptions by looking at the alignment and grades of the existing trails. If the alignment is straight and gains 100 feet of elevation in only 200 feet (50 percent trail grade), it is probably a hillclimb or fall line trail and is probably not sustainable.

If there are two trails that parallel each other and both go from Point A to Point B, examine the inventory data to determine which one has the most sustainable characteristics and provides the best recreation experience. Keep the most sustainable one and consider the other for closure. If both trails can be made sustainable and one provides a higher degree of challenge, consider keeping both trails if they fall within trail density or other constraints.

Often, the existing trails do not flow in the proper direction. They go up the slope, but sustainable trails go across the slope. If the existing trails do not provide access toward a desirable area or feature, they will become possible candidates for closure. The point here is to start eliminating the obvious. These trails can always go back on the trail concept plan if needed once the process progresses.

Next, planners should look for dead-end trails. There are two types of dead-end trails: those that end at a destination and those routes that just end. The former are opportunities, the latter can be traps. If a trail ends at a viewpoint, unique feature, or structure (i.e., a destination), then the trail will work as a dead-end trail. If the trail just ends, planners should look for a way to loop it back into another trail. From an OHV management perspective, no one likes to ride out to the end of a trail and turn around and come back the same way. This significantly detracts from the quality of the recreation experience. Instead, riders will tend to look for various ways to connect into another road or trail and this can lead to a proliferation of user-created trails and potential resource impacts, and management has lost control of the use. If for some reason it is impossible to make a loop out of a dead-end trail, consider slating it for closure.

Examine the Road Inventory

There is a wide range of road classifications and standards from interstate highways to primitive logging roads. For simplicity, it works quite well to have just two standards or two colors for roads: one for primitive low-standard roads that are suitable for high-clearance vehicles; and one for higher standard roads that are maintained for passenger cars. These would correspond with the USDA Forest Service road classifications of Maintenance Level 2 roads (ML2) and Maintenance Level 3-5 roads. Just like the trails, planners should look for the obvious. Which roads can have mixed use? Which roads can be closed and converted to trails? Which roads will require the least maintenance? Which roads provide a transportation experience and which provide a recreation experience? Answering these questions will help the planners determine the roads or sections of roads that could or should be incorporated into the trail concept plan.

Establish a Perimeter Trail

It isn’t always possible or desirable to have a perimeter trail, but there are advantages to having one. Potentially, it will be the longest trail in the trail system and that is always desirable from a mileage and seat time standpoint. The perimeter trail can also serve as the boundary trail and can help riders recognize the outer limits of the project area. The perimeter trail is a loop in itself, but it also provides loop opportunities for all of the connector trails that tie into it. In this example, the perimeter trail has nine trail connection points that create a wide variety of potential loop opportunities.

NOTE: The entire perimeter trail does not have to have the same identifier (trail number or name) although it can be desirable. Also, all segments of the perimeter trail do not have to have the same difficulty level although again, it is desirable to have consistent difficulty. If the difficulty does change from trail segment to segment, make sure the riders have the option to maintain the original difficulty level by taking another loop.

Connect the Remaining Pieces

So far, planners have eliminated trails or portions of trails, but now they need to connect the remaining pieces into a trail system with logical loops separated by difficulty level or by the recreation experience offered. Connecting the suitable roads, the suitable trails, positive control points, and opportunities into a system of trails and loops while avoiding the negative control points, prohibited areas, restricted areas, and undesirable areas can be a challenge.

To quickly disperse riders and reduce encounters and tread impacts, it’s desirable to have more than one trail out of the trailhead. Having several small loops in the proximity of the trailhead provides warm-up loops for riders and short practice loops for kids and families.

The example shows a dead-end trail and a road suitable for closure that can be used to provide two more loops. This example also shows that the planner had to eliminate the trail through two critical elk habitats. After talking with a wildlife biologist, it was agreed to cross the big game connectivity corridor between the two habitat areas as long as the length of trail within the corridor was minimized. The planner also found an opportunity to capitalize on some technical terrain in the northwest corner of the project area that avoided the cultural resource site. The dead-end trail that went to the base of the cliff was eliminated. There is a great scenic view from the top of the cliff and a trail across the rim was added to enhance the experience.

Establish Difficulty Levels

Often there isn’t enough detailed information to establish difficulty levels at this time, but if some of the difficulty is known, planners can start plugging that information into the trail concept plan. Planners and designers often hear: “I want more of the tough, technical stuff.” The reality is that the percentage of riders desiring that experience is the lowest, so often the most difficult trails are the ones that are under-utilized. Planners still need technical trails to provide that opportunity, but the bulk of the recreational riders are seeking the easiest and more difficult trails.

Planners can assign the standard colors for difficulty with green being easiest, blue being more difficult, and black being most difficult. In general as the difficulty increases, clearing and tread widths decrease, grades can increase, and obstacle size and number increase.

To help manage risk and avoid trapping riders by forcing them to ride over their skill level, there are two guidelines: a) difficulty levels must only change at trail junctions, not between; and b) never terminate an easier trail on a more difficult trail. If there is one or more short sections of more difficult terrain on a trail, instead of increasing the difficulty level of the entire trail, planners should consider making an easier trail around that section in line with the difficulty level of the rest of the trail. These easier sections around an obstacle are called easy-outs.

For this example, the planner saw there were four areas with issues. In the center, two easiest trails terminated on a more difficult trail. The solution was to correct the inconsistent difficulty by connecting the two easiest trails together with an easy route and leaving the more difficult trail as a loop (but signing it as more difficult).

At the top on the perimeter trail was a section of trail that was more difficult with the easiest trail on each end. There was no way to loop around that section and still be on an easy trail. Using the planner’s knowledge of the ground and examining the contour map, it was decided to build an easiest connector trail to avoid the more difficult section. This added another loop to the trail system and made the difficulty of the perimeter trail consistent.

And the trail concept plan is now complete.

In another example, the inventory shows that there were no existing trails, but there were some interesting features like the viewpoint, cliffs, a landing, and a rock quarry.

The landing was large enough to be converted into the trailhead. The rock quarry, though still in occasional use, was suitable to serve as a good open riding area. There was a great potential viewpoint in the center, and the rocky ground above the cliffs could provide some good technical riding opportunities.

Take a Break

Planning a trail concept is a tough mental process and should not be done hastily. At this point, planners should put down the trail concept plan for a couple of days. Then they can go back and review the plan again. Planners should review if they have maximized the opportunities and minimized the constraints. Can they add more loops or miles? Do they see something differently? If they do, then they can fine-tune the plan. If they don’t and still agree with all of the previous decisions, it’s time to move on.

Develop Trail Data

Once planners are satisfied with the quality of the product, they can start building a database or spreadsheet with the following trail information:

• How many total miles of trail will be provided?
• How many miles of trail for each use type?
• How many miles of trail construction for each use type?
• How many miles of trail reconstruction for each use type?
• How many miles of roads will be closed?
• How many miles of existing trails will be closed?

Send It Out for Review

Planners should now present the completed trail concept plan on an appropriate base map that at least displays topography, administrative and project boundaries, and key resource areas to the planning team and the project management. When the draft is reviewed and approved by the specialists, the planners should present the proposed concept plan to OHV clubs or other interested stakeholders. If substantive comments are received, planners should incorporate them into the trail concept plan, or if the comments call for a different approach, they should incorporate it into an alternative.

Develop Alternatives

If it is necessary to develop alternatives, now is the time to do that. In developing the concept plan, planners have analyzed a lot of data and made myriad decisions. At this stage, planners should keep most of what they have, but take the options that they didn’t use and incorporate them into alternatives. Then they can develop a trail database for each alternative.

Develop Generic Design Guidelines

Generic design guidelines can be written for each type of trail and will give broad design parameters for an OHM trail, ATV trail, ROV trail, or 4WD trail. Sometimes, the guidelines are called design parameters, but the term “guidelines” is preferred because it infers flexibility (the word “parameters” can infer a set of limits). The design guidelines can be used in environmental documents to help establish acres of impact. They also give the stakeholders, and eventually the trail designers, a description of the intended vision for each type of trail.

It should be noted that a guideline is just that: a guide that gives potential ranges. Those ranges can and will change from the north side to the south side of the area and as soil type and vegetative cover changes. Some design guidelines have been developed for national application but that just won’t work because there are too many regional and local variables. It is best to take a sample guideline and modify it for local conditions based on local knowledge and field experience.

Some guidelines are also becoming so detailed that, if interpreted literally, the designers can be or feel restricted from seizing onsite opportunities. The have also been applied as the “rule” but this doesn’t work either. There are principles, but few rules. This book is about making informed decisions based on actual site conditions. Planners can’t do that if their decision space is administratively removed.

Develop Generic TMOs

It is too early in the process to develop trail management objectives (TMO) for each trail, but a generic TMO document can be written for each type of trail separated by difficulty level. This will provide important information and continuity to the person doing the location and design. Once the trails are located on the ground and all adjustments have been made to the concept plan, trail numbers, names, and agency identifiers will be added and the trail concept plan will then become the design plan or final project plan. At that time, TMOs can be written for each trail. If there is a need for the management of the trail to change, the TMOs should be updated.

The process of developing the concept plan is now complete; however, the plan is a working document so it will change as better resource data, additional inventory data, or better field knowledge of the project site is obtained. It is important to point out that a concept plan is just that, a concept. Its accuracy and completeness are directly dependent on the amount of time invested in the field and office to develop it. Some plans are compiled in a couple of days, and others are developed over a period of weeks or months.

The plan will now be handed over to the person doing the trail location and design (L&D). Certainly, for a seamless, consistent, and cost-efficient process, it is highly desirable for the planner and the designer to be one in the same. The designer will take to the field and perform a thorough reconnaissance of the entire project area; that person will validate or complete the road and trail inventory data; confirm the control points and look for others; and start to ground-truth the feasibility of the concept plan. Obviously, the more time spent in developing the concept plan, the less time will be needed to validate it and refine it. To do a good job of trail layout, the designer will need to become familiar with nearly every square foot of the project area, which can involve a considerable investment of time and money. That is why it is cost-effective for the planner and designer to be one in the same. The designer can build on the previous knowledge base of the field, rather than starting from zero.

Sample ATV Design & Difficulty Guidlines
These sample guidelines are to assist in design, construction, and maintenance. Any guideline should be adjusted to reflect local experience and actual site conditions.
		Easiest	More Difficult	Most Difficult
Grade Grade should roll and not be sustained	Typical grade:	< 20%	< 25%	< 30%
	Max. Pitch:	Maximum grades are the exception, not the rule
	Grade:	15% - 20%	20% - 30%	> 30%
	Length:	Variable 50' - 100' dependant on soils,use type and use intensity, and climate. As grade increases, length on grade should decrease.
Clearing	Width:	60" to 72"	50" to 60"	50" Maximum
	Height:	7'	6'	6'
	Helmet and leg slappers:	Few	Many	Common
Tread		Width, Minimum
	Sideslope <25%:	60"	50"	50"
	Sideslope 25% - 70%:	60" to 72"	55" to 60"	50"
Surface		Some roots or rocks, obstacles rarely exceed 6-8" and are imbedded solidly in tread; obstacles generally on tangents; tread plane relatively flat with 15% max. outslope for short sections; sweeping curves and some circular climbing turns, more open alignment with circular longer radius curves; sand acceptable and some sections of slippery clay or loose material.	Many roots or rocks, obstacles rarely exceed 8-10" and are loose; obstacles on tangents and some on curves; tread plane flat to irregular with 25% max. outslope for short sections and long sections with less outslope; climbing turns and some circular switchbacks; sections of tight alignment with circular short and long radius curves; sand acceptable and long sections of slippery clay or loose material.	Very many roots or rocks; many obtacles exceed 10"; obstacles on tangents and curves; tread plane very rough and irregular with long sections exceeding 25% outslope; non-circular climbing turns and switchbacks; long sections of very tight alignment with non-circular curves; entire trail may be soft sand, slippery clay, loose material or mud.
Exposure		None	Some, potential injury	Could be common, potential serious injury
Maintenance		Trails receive appropriate maintenance to remain within their TMO, maintain effective signing, and to protect resource values.

Section 1: Trail and Engineering Terms

Understanding Trail Terms

The three trail types are terra firma or land, water, and over-snow. For the purposes of this book, terra firma trails are discussed. The winter use of summer trails and the summer use of winter trails (snowmobile trails used for OHV trails) are discussed later in this book.

Horizontal run is the distance a slope runs along the ground. The vertical rise is the distance the elevation of the slope is increased. The angle of the cut slope and fill slope is normally expressed as a ratio of the horizontal run over the vertical rise. If a run is 1 foot and the rise is 1 foot, the slope is 1/1 or 1:1. If a run is 2 feet and the rise is 1 foot, the slope is 2/1 or 2:1. If a run is 1 foot and the rise is 2 feet, the slope is 1/2 or .5:1.

Backslopes are commonly 1:1 or steeper (.5:1) and fill slopes are commonly 1.5: 1 or flatter (3:1). The soil type dictates the slopes that will be most stable for that particular type of soil. (More on that later.)

The trailway is the area from the top of the cut to the toe of the fill. By tracing a line down from the top of the cut to the inside trail shoulder, across the trailbed to the outside shoulder, and down the fill slope to the toe of the fill, a trail prism is created.

On flat ground with a sideslope of 0 to 10%, the entire trail prism is either going to be above the natural ground, called a through fill; or below the natural ground, called a through cut.

As the slope of the natural ground steepens to around 35%, the trail prism lies on the ground as a cut and fill or balanced section, which means that the amount of material excavated or cut will compact into the amount of embankment or fill needed.

On sideslopes of 70% or steeper, the ground is too steep for a stable fill to be constructed so the entire trail prism is excavated. This is called a full bench section. The material excavated is usually wasted over the side, but with the proper equipment and sufficient funding, it can be hauled back to be utilized for fills elsewhere on the project. This is called end haul and it may be required in sensitive areas that do not allow the wasting of material.

Why is the trail prism important? The prism can be dictated by the slope of the topography, but that isn’t always the case. Trail design is all about options and making informed decisions after weighing the advantages and disadvantages of each option. If the trail is in a wet area or in an area subject to heavy rainfall, a through fill prism raises the trailbed above the natural ground so it will stay drier. In the through cut scenario, water will become channeled and collect on the trailbed making it more difficult to drain the water off the trailbed. When fills become saturated with water, they can fail. Whereas trails constructed as full bench prisms will have the least risk of failure. Given the soil, climate, and storm patterns, designers may choose to build an entire trail as a full bench or a through fill prism, or they may choose to use all four prisms and apply rock hardening in areas of through cut or cut and fill. Is one wrong and one right? No. What is important is recognizing the thought process and evaluating options.

The trailbed is normally configured into one of four shapes: flat, insloped, outsloped, and crowned. While flat is the most common for OHV trails, insloped, outsloped, and crowned trailbeds can be used to control and direct the flow of water.

An insloped trailbed sheets the water to the inside so the inside shoulder essentially becomes a ditch unless a ditch is actually constructed as part of the trail prism.

When inslope is constructed on curves, it is generally used to superelevate the curve. This holds riders into the curve and allows riders to carry more speed through the curve, which increases flow and can decrease tread impacts.

An outsloped trail is intended to sheet water evenly off the outside shoulder of the trail.

Continuously outsloped trails are awkward, if not difficult, to ride on an OHV. This is especially true in wet slippery soils and on curves where the outslope acts as a reverse superelevated turn that tends to slide riders off the curve, rather than hold them on it.

A short section of outslope is usually used in grade reversals, grade breaks, or rolling dips to help force the water off the trail.

The crowned trailbed is intended to sheet the water in both directions. Most roads are constructed with a crown, but it is far more difficult to build a crown and maintain it on a narrow, natural surface trail. Crown can work well on wider trails that are hardened to hold their shape.

For any prism other than flat, the key to have it effectively sheet water is regular maintenance. If the team doesn’t have the budget, personnel, skillset, or equipment to routinely perform this maintenance, do not rely on a shaped trail prism for water control.

Design and Management Implications of the Trail Prism

• The configuration of the trail prism can affect the stability of the trail.
• A full bench prism will always be more stable than a cut and fill prism.
• Mechanical compaction during construction will improve the stability of the trail and the durability of the trail tread.
• The shape of the trailbed can affect water flow, trail flow, trail difficulty, rider experience, and rider safety.
• An outsloped trailbed should not be used in fine-grained soils that become slippery when wet.
• Any trail prism other than flat will require increased maintenance to keep the shape functional. Relying on maintenance and the shape of the trail prism to control the flow of water can be a trap.

Understanding Engineering Terms

Engineers see the world in a three-dimensional view that allows them to take any point along a trail and view it on paper or on the computer in 3-D. The three views are the plan view, the profile view, and the cross-section view. The plan view is from the top looking down on the horizontal alignment of the trail. The horizontal alignment is comprised of a series of tangents (straight lines) and curves (arcs). The shorter the tangents, the more serpentine or curvilinear the trail becomes. A curvilinear trail provides more flow, and a linear or straight trail provides less horizontal flow. While the linear trail appears to be fast and boring, it does have its place in the realm of OHV trail design.

The plan view shows the trail route. What it does not show is the smoothness of the trail surface: smooth equals fast, rough equals slow. The plan view also does not show the character of the vertical alignment. For that, the profile view is needed.

The profile view is from the side. It shows the vertical alignment of the trail. The vertical alignment is also a series of tangents and curves that represent the elevation or grade changes from one point to another along the trail. Horizontally, a trail should constantly move from side to side, and vertically, the trail should constantly move up and down. Both of these are essential for sustainability and quality rider experiences.

Trail grade is one of the most critical elements and often the most abused element in OHV trail design. As grade increases, so can rider experience, but water velocity also increases, which potentially decreases trail tread stability and sustainability. This is a major dilemma in design: how to create a fun trail without excessive grades. (More on this later.)

Above is the profile view of the same trail segment shown in the plan view. A rolling grade has recurring grade reversals, which means that the grade goes up and then it goes down. Grade reversals are 100% effective at stopping water flow down the trail. The shorter the interval between grade reversals, the less water volume, velocity, and potential erosion and sedimentation.

The third engineering view is the cross-section view, which is a cutaway view of the trail’s transect, slicing into the ground and then viewing it from the end.

The schematic below summarizes the three views. Note the frequent grade reversals.

Tangents and curves comprise the horizontal alignment of the trail. Any two points make a line or tangent and any three points can make an arc or curve.

There are two types of curves: circular and non-circular. Circular curves have a constant radius and non-circular curves have no radius as in a spiral or parabolic shape. Circular curves have three main configurations: simple, compound, and broken back. Simple curves have a constant radius and are easy to ride in either direction. The smaller the radius, the sharper the curve.

Compound curves start with one radius and end with another. In the example to the right, the curve is rideable in a clockwise direction, but not easily rideable in a counterclockwise direction. Why? Riders will adjust their speed accordingly to negotiate the larger radius curve, but as the curve tightens, they will be carrying too much speed, which often results in blown corners. Riders cannot easily stay on the trail unless they brake suddenly to lose speed. This results in skidding and excessive tread displacement. From an experience standpoint, compound curves increase difficulty when riding in the direction of decreasing radius.

Broken back curves are two simple curves connected in the middle by a short tangent. If both curves have the same radius, they can be rideable from either direction.

If the two curves have a different radius, then they are similar to the compound curve. In this example, it will be rideable in a clockwise direction, and not easily rideable in a counterclockwise direction, which again can result in tread impacts and blown corners. Like a compound curve, a broken back curve with tightening radius increases difficulty in that direction.

It is human nature to accelerate as the sight line increases. As the length of a tangent increases, the speed increases accordingly. Having a chance to increase speed improves the rider experience by adding variety, but it also decreases seat time. Designers and managers need to recognize that most riders will ride a trail as fast as they can within their skill level. This is part of the desired challenge of providing for the riders’ needs. Most riders challenge themselves. This means that speed and any resulting impacts are always factors on any trail.

Whether a trail is linear or curvilinear, the tangent lengths, curve radii, and the sequencing of those tangents and curves can affect the trail flow, difficulty level, rider experience, and potential tread impacts.

Speed increases with the length of the tangent, but what happens when the tangent ends in a curve? If there is a long tangent and then a short-radius curve (poor flow), riders will have to brake hard to negotiate the curve. Coming out of the curve, riders eye the next tangent and start rolling on the throttle. These two actions result in increased forces being applied to the trail tread creating potentially severe tread impacts called brake chop and acceleration dishing. These two impacts can be reduced by: a) shortening the tangents, b) increasing the radius of the connecting curve so it can be negotiated at a greater speed, c) superelevating the curve so riders can carry more speed through the turn, or d) a combination of the above.

Tangents and curves play a similar role in the vertical alignment of the trail. A long tangent in this case means a long grade up or down, which again can result in an increase in rider speed. It also means that any water on the trail is going to increase in volume and velocity, which will increase erosion. Both of these actions can create significant tread impacts. Short or no tangents between curves increases the rider flow in the horizontal alignment. It also increases rider flow in the vertical alignment and decreases water flow.

Water collects on the trail and then starts flowing down grade. The longer it flows or runs, the more velocity it gains and the harder it becomes to turn the water so it will drain off the trail. On a constant or unbroken grade, it is very difficult to effectively get water to drain off the trail. Four main profile shapes are utilized to get water off the trail: grade break, grade reversal, rolling dip, and waterbar.

A grade break is a place where the prevailing grade flattens off for a while without changing from negative to positive. As soon as water hits the flatter section of grade, its velocity reduces significantly and it will start to drop its load of sediment. If the trailbed is outsloped here, there is a good opportunity to turn the water and drain it off the trail. The flatter and longer the grade break, the more effectively it will drain.

As discussed with the profile view, rolling the grade by changing from negative to positive is 100% effective in stopping water flow down the trail. This is called a grade reversal and it is flagged into the trail location on new trails or the relocation of existing trails; therefore, it is a natural feature and not a manmade structure. The longer the grade reversal and the greater the elevation difference from the bottom to the crest where the grade rolls down again, the more rideable and effective it will be. Ideally, the grade is reversed for 50 feet or more, but the minimum is three times the design vehicle length unless terrain features are incorporated. There should always be a minimum of two feet of elevation difference or gain, otherwise the forces of tires, rutting, and erosion may cause them to fail. If properly designed, a grade reversal will not fail to function due to weather, amount of use, or lack of maintenance (though ponding may occur). Because of this, a grade reversal is always the preferred method to provide drainage.

A rolling dip is usually installed on a long section of constant grade to provide drainage where there was previously none. Many refer to these as grade reversals and technically they are, but they are a manmade structure, not a natural terrain structure like the grade reversal. Rolling dips are often installed as a maintenance or reconstruction action on roads, road to trail conversions, and user-created trails. They do work, but they require regular maintenance to stay effective. The longer the distance from the sag to the crest of the dip, the more rideable and more effective the dip will be. About 15 to 20 feet is ideal. The shorter the distance, the more the dip functions like a waterbar. On steeper grades, a rolling dip acts like a ski jump. In doing so, forces are applied to the crest, which will increase the need and frequency for maintenance. Also on steeper existing grades, the over-steepened slopes going into the sag and out of the crest may exceed the maximum grade for durability for a given soil type.

Waterbars, the last category, are also used on existing trails but are not effective on OHV trails. They are short rolling dips with only 2 to 5 feet from the sag to the crest. These create an abrupt hump in the trail and the force of the tires against this hump will cause rapid deterioration and failure of the structure. On ATVs, ROVs, and 4WDs, waterbars are uncomfortable to negotiate and typically there is hard braking going into them and acceleration coming out of them, which results in lack of flow and further tread impacts. Waterbars require the most maintenance and are the least effective method to drain water off the trail. Rolling dips roll and flow, waterbars don’t.

Design Implications of Horizontal and Vertical Alignments

• The configuration of horizontal and vertical alignments affect rider experience, rider speed, and rider flow, and have some effect on the velocity and volume of water.
• Trail flow is a constant series of serpentine horizontal and vertical curves. Flow does not necessarily equal speed.
• Less flow potentially has more tread impacts
• High flow equals a high fun factor
• Water creates issues and it only flows downhill. A grade reversal blocks that downhill flow and if provided regularly, reduces the velocity and volume of water.

Guidelines and Rules

It is human nature to want hard numbers: what is right and what is wrong? Many people will ask, “How steep is too steep?” As is often the case, the answer is, “It depends.” The next question people ask is, “Then what is a range or a guideline?” This is a trap not only because of site variables but also because guidelines tend to become rules.

One such rule is that all trails should be outsloped at 5%. In principle, there is nothing wrong with outslope. Every opportunity to get water off the trail is a benefit. The tread shape, however, will change over time from the shape it had right after construction through the forces of compaction, displacement, and erosion. Unless the tread is regularly maintained or is hardened to maintain its shape, the outslope will likely fail, especially with OHV trails. It’s a trap for designers to assume that outslope will work. On curves, outsloped trails can be awkward to ride in a motorized vehicle. On tangents, riders will tend to hug the upslope edge and potentially widen out the trail. In areas with slippery soils and steeper terrain, an outsloped trail can increase the difficulty level by increasing the exposure or risk of the vehicles and riders sliding off the trail.

Another rule is called the half rule. It states that a trail grade should not exceed 50% of the grade of the sideslope, so on a sideslope of 30%, the trail grade shouldn’t exceed 15%. The theory is that if the tread is outsloped, overland water will sheet across the trail if the grade is less than 50% of the sideslope, but will be intercepted by and run down the tread if the grade is more than 50% of the sideslope. This is a trap. On motorized trails, the outslope will likely fail; the tread will become a trench; and water will be intercepted by and run down the trail. While flatter grades are a definite benefit, designers of a motorized trail should always assume that any water intercepted by the trail will run down the trail. The key point for the designers is to recognize that the steeper the grade, the more velocity the water will have, so the length of the grade needs to be shorter to reduce the potential for scouring and sedimentation.

One final rule is called the 10% average grade rule. While increasing grade increases the risk of erosion, designers also need to recognize that increasing grade enhances rider experience. The problem with this rule is that most people don’t understand what it means or how to apply it. This so-called 10% Rule often gets misinterpreted to mean that the maximum grade for a trail should not exceed 10%. This is not correct. It means that the average grade on a given section of trail should not exceed 10%. In the example to the right, there are plus and minus grades with some up to 29%, but the average grade from Point A to Point B is 8.2% over a distance of 1.5 miles. (6875 – 6225 = 650’ rise, 1.5 X 5280 = 7920’ run).

What if the grade was a straight line from one end to the other? The grade would still be 8.2%, but would it be sustainable? No. So the length of the trail segment has a significant bearing on the outcome of the average grade. What length should be chosen? There are too many variables for this rule to be useful. Instead of rules, field personnel need to understand the physical forces that will be applied to the trail and make informed choices.

Section 2: Physical Forces Affecting the Trail

Things that make OHV trails unique from a design and sustainability standpoint are the vehicles themselves which have a motor, weigh more than most other trail modalities, and have torque of a wheel under power. These all create forces that are applied to the ground. Designing for sustainability requires understanding how the forces of compaction, displacement, and erosion impact the trail.

Compaction, Displacement, Erosion

Compaction is the downward force of the vehicle onto the ground. The amount of this force is influenced by the weight of the vehicle, occupants and gear, the number of tires, and the size and inflation pressure of the tires. Compaction is measured as pounds per square inch (PSI). As the contact area of the ground increases, the PSI of contact decreases. A 500-pound vehicle with four tires has more contact area, thus less PSI, than the same vehicle with two tires. In snow, sand, and mud, riders typically decrease the air pressure in their tires. This gives them more grip because their tires have more contact area.

Displacement is the physical movement of the trailbed surface particles as a result of the ground contact and torque of the vehicle. The softer and less cohesive the trailbed surface is, the higher the potential for displacement. Displacement is a force caused from human and animal interaction with nature, such as from tires, horse or other animals, a person walking, etc. A tire with high air pressure will generally cause more displacement than the same tire with lower pressure.

Erosion is the movement of the tread surface particles due to natural causes like water and wind. Again, the softer and less cohesive the trailbed surface is, the higher the potential for erosion. If displacement has also occurred, the potential for erosion increases since soil particles have already been loosened and ruts have been created to channel the water and thus increase its velocity and potential for scour.

A basic theorem of physics 101 is that for every action, there is an equal and opposite reaction. If the OHV applies 100 PSI of downward force to the tread surface, the tread surface will react with 100 PSI of upward force. The amount of upward force will always equal the amount of downward force. If the trailbed surface is inflexible, as in solid rock or pavement, the physical forces are depicted by the diagram below. The downward and upward forces represented by the size of the arrows are equal and directly opposite.

As the hardness of the trailbed decreases, the tread surface cannot support the downward force so the tread deflects and the upward forces are sent in different directions. Here, the downward and upward forces represented by the sizes of the arrows are equal but indirectly opposite. This is how ruts and berms are created in the trailbed. The softer the tread surface, the deeper the rut and the higher the berm. This action is mitigated in one of four ways: a) harden the tread surface so the forces become more equal and directly opposite; b) decrease the amount of force applied by having more tires or more ground contact area, which equates to less PSI; c) decrease tire pressure; or d) a combination of any or all of the above.

The Interaction of Compaction and Displacement

When OHV tires are put on a newly constructed trail, compaction will start almost immediately and will cause the trail tread to compress. Naturally, the compaction will occur the most wherever the tires have had the most passes over any one place on the surface. For a single-track OHM trail, the compaction will be mostly in the center of the trail, but on an ATV, ROV, and 4WD trail, the compaction will create two ruts on either side of the center. Over time, the entire compacted tread will be lower than the untrafficked tread and potentially lower than the surrounding ground.

Why is this important to know? If the tread was constructed with outslope, water will no longer come down the slope and sheet across the trail as originally designed. The water will now be trapped in the ruts of the trail and will either collect on the trail or run down the trail.

As compaction occurs, the soil particles in the tread become packed together tighter as voids become filled with finer material. This makes the tread surface less porous, so now water is less likely to be absorbed into the tread. Instead, water will either pond on the surface or accumulate and run down the trail. There will be more water since it is not soaking in. As the grade increases, the velocity of the water will increase, which will increase the likelihood of scour or erosion.

The designers must recognize that these actions will occur and plan to force the water off at regular intervals through knicks, rolling dips, or best of all, grade reversals.

On flat ground, the compaction will cause water to pond up in low areas. If the trail is not confined by vegetation or topography, riders will tend to go around these ponds thus widening out the trail tread or make alternative routes that results in trail braiding.

Once all of the voids are filled and the tread is consolidated, compaction will cease unless the vehicle types change. This may happen naturally, as when a new type of allowed vehicle begins to ride the trail. This can also be caused when the land managers open existing trails to new types of vehicles. If the managers allow ROVs on trails that previously only allowed ATVs, the forces on the trail will change because of the difference in vehicle weight and size. It is important that the managers recognize and plan for the potential impacts prior to changing vehicle trail designations.

The trailbed is constructed using one of four shapes: flat, crowned, insloped, or outsloped. The important point to remember here is that unless conditions are ideal, which rarely happens, all of these shapes will change over time with vehicle use and become rutted, entrenched, or concave. After compaction has occurred, the trail could be restored to its original shape through maintenance if the funding and equipment with skilled operators are available to do so. If this is not done correctly, the tread material can easily become unconsolidated and the compaction, displacement, and erosion process will start all over again.

The forces of vehicle compaction can be reduced and the integrity of the trailbed shape can be significantly improved if the trailbed is compacted during construction with a roller or other equipment. This can be labor-intensive and expensive. For the roller to have full ground contact, often rocks and roots are removed. The down side of this is that the trail no longer looks and feels natural and some riders object to that. The character has changed and so has the trail experience, but the tread is far more durable.

The crowned trailbed is more difficult and expensive to construct, but given good, non-saturated soils, once the forces of compaction, displacement, and erosion are applied, it is the only shape that is still close to the original ground line, rather than a trench below the ground line. This can be a benefit since it will make it easier to drain water off the trail and help keep the trail tread from becoming saturated.

While compaction slows down and can even cease, displacement does not. The force and torque of tires creates constant displacement of the tread surface. In addition, the forces of braking and accelerating and the centrifugal forces try to slide the vehicle to the outside of curves. All of these create progressive grinding of surface particles and displacement of the tread surface. Embedded rocks can get dislodged and solid rock can get ground away over time. Faster speeds and steeper grades will exponentially increase these forces and their effects.

Since compaction consolidates the tread particles, compaction makes the tread less susceptible to displacement and erosion, but it never stops these other forces. Trails will change over time and designers need to recognize that. In some scenarios of soil type and climate, the change has no effect on the functionality of the trail or can sometimes improve it, but in other scenarios, that change can lead to drainage issues and the loss of the trail’s integrity.

Hardening is a tool that can be utilized where needed in that latter scenario, but as with mechanical compaction, hardening changes the character and feel of a natural surface trail. Instead of riding on dirt and natural terrain features, the riders are now on gravel or some other unnatural surface, which is like riding on a miniature road. While it provides variety, it is not the experience that most trail riders are seeking.

What is the effect of displacement on a grade? The gravitational force (G) is always a vertical force. When the trail is flat, the gravitational force is close to perpendicular to the trailbed. The torque of the tire still creates some displacement.

As the grade increases, the gravitational force is no longer perpendicular, but is being applied at an angle to the trailbed. This angle, combined with the torque of the rotating tire, disrupts trail tread. More particles and rocks are dislodged and displacement increases.

As the grade increases more, the angle between the G force and the trailbed decreases, which makes the G force a more effective tool to dislodge tread particles. This increases displacement even more.

What is the effect of displacement on a curve? Just like on a grade, the angle of the force being exerted combined with the sideways centrifugal force dislodges tread particles. These particles are always thrown to the outside of the curve where they accumulate and eventually form a superelevated curve. The faster the vehicle speed and the softer the trail tread, the more rapidly the superelevation forms. If not confined by vegetation, the trail will continue to widen out until the superelevation is fully formed. Depending on the soil type, speed, and amount of use, this could take a few months or a few years to occur.

Some riders do not like superelevated corners because they don’t appear natural and riders feel like they’re on a motocross track instead of in the woods. Even in dry climates, superelevated turns can entrap water causing ponding and even soil saturation after heavy rain events. However, one advantage of superelevation is that riders can carry their speed through the turn without braking going into it and accelerating coming out of it. This creates flow and a very high fun factor. What else does it do? By having a superelevated turn, designers can eliminate or certainly reduce two of the three forces that accelerate displacement: braking and accelerating. Since the angle of the superelevated turn is now closer to perpendicular with the tire, the amount of centrifugal force is also greatly reduced as is the amount of displacement. This reduces tread impacts and reduces maintenance needs and costs.

If the trail was originally constructed with superelevated corners, there is less widening of the trail over time and compactive forces can start much earlier. A superelevated corner increases tread stability and reduces the loss of tread material because the banked tread contains the displaced soil particles and they roll back down into the tread.

Special Considerations for Four-Wheeled Vehicles

There are some special considerations when the OHV has four instead of two wheels. One obvious difference is that now there can be at least two drive tires next to each other (two-wheel drive OHMs have a single drive tire forward and rear) delivering rotational forces and potential displacement forces to the ground. Depending on tire size, inflation pressures, actual vehicle size, and weight and loading, those forces may or may not exceed those exerted by a motorcycle. The real difference, though, comes into play on curves.

When a four-wheeled vehicle is on a curve, the outside tires are on a larger radius than the inside tires. That means that the outside tires have to travel farther and faster to stay in line with the inside tires. If the tires roll independently like those on the front axle of a rear-wheel drive vehicle, the outside tire will roll more and the inside tire will roll less to get around a curve. The drive tires behave differently. If the drive axle is solid or if the differential is locked, the two tires turn at the same speed and cannot roll independently. This means that as the outside tire is traveling farther to get around the curve, the inside tire is going at the same rate, but has a shorter distance to travel, which causes wheel hop and tire spin on that inside tire. Depending on the trail surface, these forces can cause severe displacement. Non-cohesive soils, loose rocks, or pavers and other materials used for trail hardening can be churned up, broken, or moved. These forces must be considered while designing the trail.

Increasing the vehicle width increases the effect because of the larger difference in radius between the inner and outer wheels. Increasing the grade increases the effect because of the additional torque being applied to the tires. Increasing the curve radius decreases the effect because the outside tire has to turn less to keep up with the inside tire. Other than rotational forces, there is no churning effect on tangents because both tires travel the same distance at the same speed. The effects will be most noticeable on a climbing turn since it involves grade and a turn.

Erosion

The third force is erosion, which is the movement or removal of the tread surface particles due to natural causes like wind and water. Poor trail design and lack of effective drainage can accelerate erosion. Soil particles displaced by vehicle tires are more susceptible to erosion. Vehicle operation during periods when the soils are most susceptible to displacement, such as very dry or very wet (saturated), can create ruts that channel water and increases its velocity and scouring action.

Erosion is generally viewed as being bad, but it is a natural, ongoing, and eternal process. The Grand Canyon is viewed as spectacularly beautiful, but it is a product of eons of erosion.

Here are some key points on erosion:

• Erosion is a natural process that is caused by weather patterns or weather events, whether they are major or minor events.
• Major rain events and catastrophic storms like tornadoes and hurricanes will happen and they will result in erosion.
• Given the right conditions, even normal weather patterns can and do cause erosion.
• Steep ground is not needed in order for erosion to occur. The potential for erosion is everywhere and it is non-selective.
• Erosion is cumulative. Even minor soil movement from a single storm can add up to significant soil loss over several years of storms.
• While erosion cannot be stopped, designers and managers can take measures to minimize it through good design and trail management.
• The trailbed is a precious resource. Once the tread particles are displaced and eroded, they are generally gone forever. It is more efficient to be proactive and invest time and money up front in design to protect that resource rather than be reactive and try to fix the trail after the damage has occurred.
• Even if everything is done right and a sustainable trail has been built, erosion will occur to some degree. The fact that there is erosion does not necessarily mean that the planners and designers have failed or that the trail will fail.

Chapter 3 included a tip that said planners and designers are always better off trying to work with human nature rather than against it. That same concept applies here. They cannot fight a natural process and must learn to live with it. They can, however, do some things through design to reduce the impacts of that process on our trails.

The Interaction of Compaction, Displacement, and Erosion

With any natural surface trail, the vegetation at the surface gets removed and roots that hold soil either get cut through construction or broken through use. These actions weaken the soil and expose it to the forces of compaction, displacement, and erosion. Compaction can help minimize displacement. If displacement is minimized so is erosion potential; therefore, compaction helps reduce erosion also.

Many soil types appear to be stable at a given time of year, level of use, and moisture content. Change any of those three variables and the soil stability will change, which means that the potential for displacement will change. Clay soils turn to gumbo when wet. Sandy soils turn to flour when dry. Soils with low stability cannot endure a high volume of use in a short duration of time, as in an OHV event or race, unless they are frozen or have the optimum moisture content, which rarely happens.

When the surface of clay or silty soils is dry, the smaller particles become easily dislodged by the displacing action of tires and become airborne, hence dust is created. Most people, especially the riders, see this dust as a nuisance and pray for a breeze to blow it out of their way. However, what is occurring here is erosion. Those soil particles that are blown away are now gone forever, resulting in tread material being lost every year due to dust and wind.

After even a minor rain event, small rills or channels may form in the trail and at the downhill end of each rill will be a small deposit of sediment. These can seem innocuous, but over time they build up and can fill the bottoms of rolling dips and block the entrances to lead-off ditches. These rills can start forming within just a few feet of a drain and they can form on any grade, not just the steep ones.

Sedimentation from erosion can fill up drainage structures and cause them to fail, but ruts caused by displacement can do the same thing. Water collects in those ruts, becomes channeled, increases velocity, and can blow right by lead-off ditches and under-sized rolling dips. This is another reason why properly designed grade reversals are preferred over manmade structures; they cannot fail.

Compaction, Displacement, and Erosion Design Implications

• Displacement cannot be stopped, but it can be managed through design.
• The steeper the grade, the higher the displacement potential. Designers should strive to minimize grades or the length of the grades.
• Vehicles with locked or solid axles can increase displacement on curves. This is exacerbated if the curve is on a grade.
• Rolling dips require regular maintenance and are prone to failure. It is best not to rely on manmade drainage structures if possible.
• Properly designed grade reversals cannot fail. Designers should roll the grade to provide frequent and positive drainage. This also increases the fun factor.
• The longer water runs, the more velocity it will gain, and the more sediment it will carry with it. Designers should provide frequent grade reversals or drainage structures to minimize the water run.
• Superelevated curves can reduce tread impacts, reduce displacement, and increase the rider fun factor. If consistent with the TMOs, consider superelevating the curves.
• Displacement potential increases with speed, so design the trail to reduce speed, which in turn increases seat time.
• Tread impacts can be created by braking and accelerating. Strive to minimize these occurrences by maximizing flow, using circular curves rather than compound or broken back curves, minimizing speed, and decreasing the length of tangents.
• Trail design is a process of understanding the riders, their desires, the physical setting, and the natural forces at work in that setting and using that knowledge to make educated decisions. There are few rights and wrongs in design, rather there are trade-offs. If the designers increase difficulty, will they increase the risk of tread impacts? If so, is that okay in the setting?
• If designed properly, trails will be most susceptible to compaction, displacement, and erosion within the first year after construction. Normal weather events can actually help compact the trail tread. If a trail is constructed in the fall, consider closing it to use until the following spring. If a trail is constructed in the spring, consider closing it until there have been several weather events. Try not to schedule an event on a trail within the first year after construction.
• Soil stability and thus the potential for displacement changes with the season, moisture content, and use level. Consider closing trails during the seasons of instability like spring break-up, the monsoon season, or the heat of the summer.
• Some soils, like clay, have extreme displacement potential when they are saturated. Monitor the soil moisture content and close the trails to avoid use during those period.
• Schedule events during the times when soil stability is likely to be the highest.
• Use websites and other media to educate riders about responsible rider ethics and expected behavior and to inform riders to avoid riding during periods of tread instability and of trail closures or restrictions.
• Train trail personnel to look for indicators of problems before they become major issues.
• Utilize the 4Es to actively manage and control OHV use, both on the trail and off the trail. Enforcement must coincide with education.
• Recognize that compaction, displacement, and erosion will occur and seek long-term funding to ensure that trained and experienced staff and the proper equipment are available to perform monitoring, maintenance, and eventual trail reconstruction where and when it’s required.
• Trail management is also a process of making educated decisions. Erosion is a natural process and it will occur. There are design options to minimize the risk or level of that occurrence, but if those options cannot be exercised there are several management options that are discussed later in this book.

A Second Look...

It was discussed previously how erosion has washed away the fines and left a rock garden on this section of trail. What if that water has no direct connectivity to a stream? What if this trail had a higher difficulty level? What if our options to relocate this long grade are limited? Is it okay to accept this? Under certain conditions, the answer can be yes. For example, as long as signing and mapping reflect the appropriate difficulty level, the trail could be managed as More Difficult. On the easier trail sections on both ends, some simple entrance management techniques could be implemented to indicate to the riders that there will be more difficult sections to negotiate.

Section 3: Understanding Tread Materials

Natural surface trails generally use the native soil as the tread surface. Some soils are more stable and durable than others. Indeed, soil type is one of the key elements, if not the key element, in trail design. Unless the soil is modified or hardened, it will dictate the steepness of grade, tightness of alignment, frequency of drainage, smoothness of the trailbed surface, and the level of difficulty. Tread materials are generally composed of a mixture of soil and rock.

Soils

Soils are composed of different mixtures of sand, silt, and clay (called the soil separates) with the additives of organic matter (humus) and larger mineral fragments such as gravel-sized material. The mixtures of the soil separates define the texture of the soil and the texture influences the behavior of the soil. Will it drain? Will it displace? Will it be slippery? It is very common for the soil type or soil mix to change several times on any given trail, so the designers must be constantly watching for these changes and adjust the design accordingly.

Clay soils have the smallest particle size and the particles are shaped like flat platelets. The platelet shape makes clay very durable when there is sufficient moisture to bind the particles together. They can hold a lot of water, which makes them poor draining, and when wet, those platelets slide over each other, which is what makes a clay soil so slippery. Clay has high cohesion and that means it holds onto and binds particles together. That’s why it feels sticky when moist. A quick field test is to take a handful of the soil, apply enough water so the sample is moist (wet, but not saturated), and then make a fist to form it into a ball. A clay soil will form a ball. Then rub hands together to try to roll the material into a pencil shape. A clay soil will roll into a pencil; the thinner the pencil, the higher the clay content.

Silt soils are the next larger particle size though the particles are still small and not visible. Silt feels smooth like flour. Due to their particle size, there are numerous voids between them, so they can hold a lot of water but not as much as clay, so they drain better than clay. Silt has medium cohesion, so it will also bind particles together to make a firm trail tread. In the field test, a silty soil will form a ball and feel smooth, will not be as sticky as clay, and will not roll into a pencil.

Sand has the largest particle size and is visible and gritty. The pores between the particles are large, so water drains through them very easily. Pure sand has no cohesion and does not bind with other particles, so sand does not compact and is therefore easily displaced. In the field test, pure sand will not form a ball and will disintegrate easily when pressed lightly.

Rarely is a soil one pure particle type. Instead, it is a mixture of the three soil separates, which is a good thing since pure soils are not desirable for a trail tread. When mixed together though, the soil, which is called loam, tends to have more of the advantages of each of its components and less of the disadvantages. The relationship between the particle types is often displayed in what is called the soil triangle with clay, silt, and sand in each of the three corners and the combinations of loam near the center.

The table displays the properties and behaviors of each soil type.

Humus is a dark brown to black layer of decomposed organic material often referred to as the A horizon. When mixed with the soil separates, humus significantly increases the bulk density and moisture retention characteristics of the soil. Being organic, it also adds nutrients that stimulate plant growth which in turn can help stabilize the soil. Like the soil separates, in the right mix humus is good, but the higher the percentage of humus, the more muddy the soil will become making it very susceptible to displacement and erosion.

The ideal tread material is a loamy mix with humus and a significant gravel content. Such a mix will provide stability, durability, and drainage. The mixture will be able to withstand the forces of compaction, displacement, and erosion. Unfortunately, that ideal mixture is generally not very prevalent, hence the need to either modify the trail design parameters or modify the tread material.

There is comprehensive soil mapping and soil information available for every state and county in the United States through the USDA National Resources Conservation Service (NRCS). NRCS provides tables that interpret soil map units for different uses. Those interrelations vary depending upon the age of the surveys, but often there are interpretations for light roads, or foundations that may be useful to the trail planners. Their website has just about everything planners and designers would need to know about soils. Soil mapping for Canada is available through the Agriculture and Agri-Food Canada, National Soil DataBase (NSDB). Many federal, state, and provincial agencies also have their own soil mapping database. As with any area mapping product, the level of detail may not be sufficient for the desired application, so some level of ground verification is usually needed to ensure the accuracy of the data.

Rocks

Most tread materials also contain unconsolidated bedrock or loose rocks. In the right mix of size, shape, and content, rocks can add to the durability of the soil. And like soils, these materials are also categorized by size. There are four classes:

• Gravel: 2 to 75 millimeters (mm) (sand size to 3”)
• Cobbles: 75 to 250 mm (3” to 10”)
• Stones: 250 to 600 mm (10” to 24”)
• Boulders: larger than 600 mm (larger than 24”)

These materials are a benefit to any trail tread because they provide weight bearing and durability by resisting the forces of compaction, displacement, and erosion. They also add to the natural character of the trail, so they increase the rider experience. A challenge for OHV trail designers is how to provide challenge and still have sustainability. Rocks can help provide that opportunity. Soils with a high angular rock content may allow the designers to increase the grade. Exposed bedrock, firmly embedded rocks, slab rock, slick rock, and boulders can provide outstanding technical challenge while maintaining tread durability.

Unfortuantely, a rock is not always as hard as a rock; some are durable and others are not. The three types of rock are igneous, sedimentary, and metamorphic. Igneous rocks have solidified from a molten state. They are tough, hard, and have little texture or layering. Examples are granite, dense basalt, and obsidian. Sedimentary rocks have been formed by the accumulation of particles that have been compressed under heat and pressure to create rock layers of hardened sediment. These are not as hard or durable as igneous rocks. Because the rocks are compacted in layers, each layer may have a different density and bonding strength, hence the layers can separate under the forces of turning tires. Examples are sandstone, limestone, shale, and gypsum. Metamorphic rocks are older rocks that have been altered by extreme pressure, temperature, or chemical actions. These are tough, hard rocks. Examples include quartzite, schist, marble, and gneiss.

Depending on their compositon and hardness, some rocks on or near the surface tend to weather more than others. The forces of expansion and contraction created by hot and cold cycles cause micro-fractures and the freeze-thaw action of water expands those fractures and weakens the rock. Therefore, rocks near the surface may become rippable even though they appear solid. Depending on the type of rock, this weathering could make the rock rippable for a few inches or a few feet. As designers lay out a trail, they should be looking at and assessing the protruding rock. Is it rippable or is it tied to the center of the earth? Should it be taken out, circumvented, or left as a challenge feature? A couple of quick pokes with a pick or other implement will give designers a hint as to the solidity of the rock. The designers should remember that the material will be harder below the surface.

With the softer rocks moguls, can actually develop in the rock or grooves can be cut into it by tires. Softer rocks used as technical features can literally disintegrate over time. Rocks that have cracks or fracture lines are likely to break along those lines under the forces of vehicles. Does that mean that the designers should avoid utilizing the softer rocks? No, any rock is better than no rock, but the designers need to realize that changes will occur. Ten years of durability is better than none, and ten years of providing a high-quality rider experience is better than none.

Another type of common tread material is decomposed granite or DG. It is granite rock that has weathered and broken down into various sizes from gravel to sand-sized particles. Depending on the area and the mix of sizes, it can be a good tread material or a very poor one. It tends to have round particles, but if there is a good mix of sizes, or if they have been mixed with other soil types, especially clay, they can produce a durable tread. If the particles are homogeneous regardless of their size, they do not bond together and displace very easily.

Volcanic rock, being molten from the ground, is igneous rock that includes basalt, rhyolite, and andesite. Basalt is the most common and it has several forms depending on how quickly the lava cooled and how much gas was trapped in it forming vesicles. A gray lava flow is basalt. It can be very hard and durable with a low vesicle content, but it gets weaker as the size and number of vesicles increases. The reddish lava rock are cinders. They are highly vesicular. The tan to white pumice has so many vesicles and trapped air that it floats. Cinders and pumice make poor tread materials because they are granular, weak, and non-cohesive. They will compact over time, but they are dusty as they break down and with no cohesion, they displace very easily. Loose pumice on the surface of the trail tread can float away in a heavy rain, which is undesirable in a tread material.

Design Implications of Rocks

• Bedrock or well-embedded rocks provide superior resistance to compaction, displacement, and erosion.
• Angular rock binds well with other tread materials as long as the voids between the rocks are filled with a variety of other rock and soil particle sizes. The more rock, the more durable the tread becomes. This could allow for steeper grades.
• Round rock like river rock does not bind well with other tread materials and can be easily displaced.
• If all of the rock particles are homogeneous in size, both angular and round rock can be displaced. Consider mixing in clay and other soil and rock particles as a binder.
• Rocky treads tend to drain well so they do not become muddy when wet, but they can get slippery.
• Gravel, cobbles, and stones can be used to harden wet areas.
• Hard rock doesn’t erode, but the soil particles around it does. Frequent drainage is still important to control water volume and velocity.
• Soft rock can break down and erode.
• Rocks with horizontally oriented sharp edges can be tire busters and rim benders. Either break off the edges or pad the approaches to them to reduce the angle and force of impact.
• While surface rocks provide variety and challenge, less experienced riders will often try to ride around them if possible, which creates widening of the trail. Strategically place boulders, logs, or other barriers to deter this widening. Better yet, if possible, provide an easy-out around the rocky area.

Section 4: Understanding the Dynamics of Water

In trail design, speed and water create issues, but both can be managed through proper design. Designers can roll the grade to force water off the trail at regular intervals. Many factors influence how water is forced off the trail, including soil type, topography type, frequency and intensity of use, control points, trail grade, tread width, vegetation (ground cover and tree canopy), climate (arid or wet), and seasonal weather patterns (potential for high-intensity thunderstorms). All of these can affect the amount of water collecting on the trail tread and the behavior of that water. To manage that water, designers need to focus on not only the water on the trail but also the sources of that water. Certainly, as it rains water is falling directly onto the trail tread, but it is also falling on the land above the trail. Some of this water is absorbed into the ground, some of it runs as an overland flow onto the trail, and some of it drains as a subsurface flow and spurts like a spring in the trail. How much water is this and how does it influence the design? Determining how much water may enter the trail profile involves looking at the bigger picture of the landscape and dividing it into tread watersheds.

Tread Watersheds

The tread watershed is the area from one grade crest to the next grade crest and all of the land that drains into it from the top of the ridge or a topographic crest.

The topography of the site controls the height of the tread watershed, but designers can control the length of the watershed. Through the actions of compaction, displacement, and erosion, the tread sinks over time and the integrity of whatever shape it had at the time of construction is usually lost. When the tread sinks, it traps the water and the tread becomes a conduit or channel for the water to run. The water will run from the top of the grade crest to the bottom of the grade sag. The longer water runs on a grade, the more velocity it gains, and the more potential it has for scour or sediment delivery. This is called runoff erosion. To increase sustainability, these runs must be as short as possible.

Tools to Manage Water

The designers control water by rolling the grade, which not only helps make the trail sustainable, it enhances the rider experience and fun factor. This is one advantage of designing for OHVs: with a motor, riders don’t mind going up, back down, and up again. It’s not a chore, it’s fun.

In order to roll the grades and provide point drainage, designers must have the trail on a sideslope. Flat ground with flat grades does not allow the designers to control the size of the tread watershed and it becomes difficult to drain the water away from the trail.

This is one of many reasons why roads do not make good sustainable trails: the grades do not roll enough and their watersheds are too large. Roads are generally much wider than a purpose-built trail; therefore, the road surface is collecting more water volume than a trail, which can result in accelerated erosion, washouts of the road shoulders, or slope failures below the road drainage points.

When rolling dips are constructed on roads with long sustained grades to provide additional drainage, what is really occurring is that those grades are being broken up into smaller tread watersheds. This works but rolling dips require regular maintenance or they are prone to failure under normal or extreme weather events. The better alternative, if available, is to take the trail off those road segments so it can be built with rolling grades that provide shorter tread watersheds and will not fail.

Water Volume + Water Velocity = Increased Runoff Erosion Potential

Here is one example to put things into perspective. A mile of 12-foot roadway has a surface area of about 1.5 acres. A rain event of only 1” will produce about 40,000 gallons of water on this roadway. That same 1” rainfall on a mile of trail with a 50” tread will yield about 14,000 gallons of water. If that trail has a grade break every 300’, then the amount of water flowing to each drainage point will be reduced to about 315 gallons. This is the water just landing on the trail. It does not include the water flowing onto the trail from the rest of the tread watershed. As the velocity of the water increases, the number of soil particles and the size of the soil particles being carried away increases. There are variables, but the velocity of the water can double when the grade quadruples. The velocity of the water flow on an 8% grade is twice that of a 2% grade. When the velocity is doubled (2X), the volume of sediment that can be moved quadruples (4X), and the size of particles that can be transported octuples (8X). Clearly, the key to creating a durable trail is to effectively control and manage the water.

Designers can reduce the water volume by keeping the tread width as narrow as possible and by reducing the size of the tread watershed. They can reduce the water velocity by reducing the grade and reducing the size of the tread watershed

There are four factors which affect the runoff volume and speed:

• The height of the tread watershed affects the volume of water.
• The steepness or slope of the topography affects the speed of the water.
• The soil type affects the absorption of the water. If the soil type is hard like clay, has a high rock content, or is slab rock, very little water will seep into the ground and the runoff potential increases.
• The amount of vegetative cover affects the speed of the water. Thick forests or grasslands slow the runoff rate and act like energy dissipaters to stop or divert the direction of the runoff. The less the vegetation, the higher the runoff potential. With vegetation comes vegetative debris called litter such as sticks, branches, needles, and leaves on the ground. This accumulation of litter helps reduce runoff potential. This is why there can be devastating erosion after a wildfire; the vegetative cover has been removed.

Runoff erosion is created by water volume and speed, but there is another type of erosion: splash erosion. The force of the water, even a raindrop, hitting the surface dislodges soil particles and can actually make little craters in the soil. This displaced soil then becomes subject to being carried away by surface water. A tree canopy can act like an umbrella by intercepting the initial force of the raindrops and allowing them to fall gently to the ground below. By locating a trail in the trees, the potential for splash erosion can be reduced. Ground cover and the accumulation of vegetative litter also protect the soil from splash erosion.

The ideal time to design or assess a trail is during the wet season when the amount and effects of the water are clearly visible. Unfortunately, that isn’t always possible, so it’s important to visualize how the site looks when wet. Sometimes looking at existing road and trail cuts can give clues as to the water dynamics. As a trail is being located, all potential water sources to the trail must be examined. Direct rainfall or snowfall, perennial streams and creeks, and seasonally wet drainages are obvious, but other water sources may not be that obvious. There may be a subsurface flow of water and the trail, once cut into the sideslope, may intercept that water. Groundcover can often cover up tiny rills that will feed water into the trail. Springs can dry up and be hidden. Designers should look at the base of rock outcrops for evidence of seeps. A change in vegetation to a type more indigenous to moisture can be a good clue along with moss, lichens, and small dry rills.

A Closer Look...

Designers should keep trail grades as low as possible. What does that mean? Increasing grade increases the risk of erosion, but increasing grade also enhances the rider experience. If the rolling grades on the trail never exceeded 10%, it would probably be quite sustainable, but how fun would it be to ride? Providing for the riders’ needs has been a fundamental guiding principle throughout this book. The designers must be constantly assessing the risk factors in each segment of a trail and weighing reduced grade vs. increased rider satisfaction. The designers should ask if they can push the grade at this point or not. If not, what other options can be employed to enhance the experience? Trail layout and design involves a very complex mental process of asking questions and answering them. The intent of this book is to teach designers and planners which questions to ask.

Design Implications of Water Dynamics

• During trail layout or trail assessment, carefully examine all potential water sources and analyze their effects.
• Trail grades should be kept as low as possible, yet still provide the desired experience.
• Tread watersheds should be as short as possible by rolling the grade.
• Trail tread should be as narrow as possible. If converting a road to a trail, any excess width should be removed.
• Seek out vegetative cover whenever possible.
• Avoid steep, open slopes whenever possible.
• Consider other design or management mitigations such as reducing the grade, hardening the tread, increasing the maintenance frequency, or temporary closures to minimize potential effects.

Management Implications of Water Dynamics

• If designed properly, trails will be most susceptible to compaction, displacement, and erosion within the first year after construction. After the first year, compaction helps reduce displacement and erosion risk to some degree. Delaying the opening of a trail can assist natural weather events to help compact trail tread. If a trail is constructed in the fall, consider closing it to use until the following spring. If a trail is constructed in the spring, consider closing it until there have been several weather events.
• If possible, do not schedule an event on a trail within the first year after construction.
• Schedule events during the times when soil stability is likely to be the highest, if possible.
• Train trail personnel to look for indicators of problems before they become major issues.
• Schedule and perform routine maintenance.
• Consider closing the trail to use during periods of tread instability.
• Use websites and other media to educate riders to avoid riding during periods of tread instability.

The Elements of Sustainability

It is important to understand the elements of resource sustainability: engineering, the physical forces, soils, and water. This gives a better understanding of the natural environment and how to create a great and sustainable trail.

Who needs this understanding? ALL field personnel. The trail planners and designers, but also the people conducting assessments or condition surveys, maintenance personnel, key volunteers and partners, construction supervisors, and the managers all need to have the ability to look at a piece of ground and understand what is or could be going on there. With that knowledge, they can be pro-active and implement adaptive management in a timely fashion. It isn’t by accident that all of these personnel fit into the Great Trail Continuum. A great trail is only created by effectively and equally applying all five elements of the continuum together.

Sustainability Basics:

• Minimize grades. The steeper the grade, the shorter it should be.
• Minimize the tread width. This increases rider experience and decreases water volume.
• Seek creative ways to provide difficulty. Most hillclimbs are not sustainable.
• Keep tread watersheds as short as possible by rolling the grade.
• Design the trail with horizontal flow to minimize displacement.
• A trail with horizontal and vertical flow increases sustainability and rider experience.
• Avoid the fall line and flat ground.
• Vegetation and topography are friends.
• Speed and water can cause impacts.
• Identify all sources of water entering the trail and manage that water through design.
• Conduct monitoring and trail assessments.
• Perform maintenance when it’s needed, and not let it backlog.
• Apply proactive and adaptive management.
• Changing use type or use levels of trails could lead to unsustainable trails. Reassess the impacts and risks first. A trail that is sustainable for one use type may not be sustainable if the use type changes or if the use level changes.

Section 1: Gearing Up for the Field

Safety and Risk Management

The field is a wonderful place, but it is full of personal risk. Before heading to the field, the team needs to take some time to examine the risk factors and mitigate them. The primary objective every day is to come back safely and the team does that by stacking the odds in their favor; being prepared and alert. What is the weather forecast? Dress accordingly. Are the soils slippery when wet? Wear appropriate footwear. What insects are in the area: bees, mosquitos, ticks, chiggers, scorpions? Wear appropriate clothing; take insect sprays; and look before walking, sitting, or reaching. If someone is allergic to any bites or stings, take an Epi kit. What animals are present: bear, deer, elk, moose, or domestic livestock? Don’t be too proud to wear a bear bell or pack bear spray. What poisonous reptiles are present? Again, look before walking, stepping, and reaching. Snake gaiters are hot, bulky, and certainly not fashionable, but the peace of mind they offer is worth it. What poisonous plants are in the area? Know what they look like and where they grow and dress accordingly. Vehicles are needed to get the team in and out of the field every day. What condition are the trucks, ATVs, OHMs, etc. in? If there should be a mechanical malfunction, how will the team get out? Is there party or drug activity in the area? Are there people who want to live off the grid? Be aware and avoid walking into a situation that may put the team at risk. Finally, know the team members’ physical limitations. If team members don’t think they can safely traverse the terrain on a given day, don’t go. Stay in and catch up on paperwork.

An item that is indispensable is a walking stick. No, they are not just for old people. Walking sticks give each team member added stability on steep or slippery slopes. They provide additional balance while walking on logs or over other potentially hazardous terrain or obstacles. The best way to break an ankle or bust out a knee is to step into a hole. With the sticks, team members can poke through the ground cover ahead of them to make sure there aren’t holes. They can use them to move limbs, brush, and briars out of the way so they can walk through them more easily. They can use them to ward off snakes or other unwanted critters. They can use them to test the firmness of the soil or hardness of rocks. They could be the last defense in a bear attack. Team members should use them to test the depth of the stream they’re about to cross. If they had to stay out overnight, they could use them for a source of wood or as ridge poles for an emergency shelter. The walking stick is a multi-purpose tool that helps keep the odds in the team members’ favor.

Certainly, one of the best things to do to keep the odds in a team’s favor is to carry and use personal protective equipment (PPE). This may include riding gear, chainsaw gear, climbing gear, hardhats, high visibility vests, etc. There is no valid excuse to not wear it. Manage risk and keep everyone safe. No one can do trail work if they’re hurt.

The goal of all of this is not only to keep team members safe, but to maximize the efficiency of the time spent in the field. Many agencies formalize the project analysis and self-protection process on a Job Hazard Analysis (JHA) form.

Basic Field Instruments

Whether doing reconnaissance of a project site, assessing an existing trail, performing trail layout and design, or establishing construction controls, the team needs to have an array of tools available to help perform whatever task is needed. Once in the field, the office, supply room, and shop are in team members’ day packs.

Consider taking a variety of key instruments and tools.

Flagging and Pin Flags

The flagging that comes in a roll is called ribbon flagging and it is offered in a variety of colors and patterns. Flagging is used to mark the trail alignment as well as various work items. Most projects have a list of flagging protocols that spell out the color and pattern to be used for each work item. It is very important that the flagging used for a trail does not conflict with what is used by other agencies or industry for timber sale boundaries, road surveys, proposed utility corridors, mining claims, seismic lines, transect surveys, etc.

A key point to remember about flagging is that it is not very durable. Deer, cows, rodents and insects eat it; the UV rays from the sun can fade the color in just a few months; and the wind, hail, and cold tear it to shreds. Hanging long streams of flagging is great for visibility, but it is more susceptible to the critters and the elements and thus has limited longevity. Shorter flags last longer. Since a large percentage of the flags will disappear, tie them close together. A 15-foot interval works well. It can be several years from the time a trail is designed to the time the trail gets constructed.

What is the best method to tie the flags? A simple overhand knot works well for temporary flags. A key thing about knots is that they should be simple to tie and untie when there are changes. A double overhand knot is not simple to undo. A bow knot is simple. One pull on the loose end and it comes off. Unfortunately, if that pull is coming from an animal, the flag will be lost. A loop knot works well. Fold the piece of flagging into a loop, place the loop over the limb, and pull the tails through. This simple knot is easy to tie and untie. Repeat the process for a double loop.

It takes more time, but tying a double or triple knot will last significantly longer and after a couple of years, only the knot will be left. The downside of using multiple knots is that it is very difficult and time-consuming to remove the flags to change the line. Tie the multi-knots on the last pass through a flagline, not the first.

A trick is to pre-tie flags onto smooth jumbo paperclips. These are easy to clip on and off, are durable, and are more visible when only the knot is left. There are four main advantages to the paperclip trick: it eliminates the fumbling and pain of trying to tie a knot in a briar patch; knots are tight and consistent since they are tied in a warm controlled environment; it is fast, clip it on and move on; and rather than focusing on reaching in and tying a difficult knot, the designers can stay focused on what the trail grade, alignment, or drainage is doing.

The paper clips come in boxes of 100. Tie a box at a time and hook them onto a string. When ready to use, transfer them from the string to a slightly modified steel spring-tensioned embroidery hoop from a fabric store and head to the field.

A pin flag is a wire whip with a colored flag on top. The length of the wire and the size of the flag vary. Pin flags are handy in open areas or meadows where there are few trees or brush to hang flagging. The longevity of pin flags can be shorter than that of ribbon flagging. The flag tends to break off in the wind and cold leaving only a rusted wire as a marker. The wire will usually stay in place and at least the critters won’t eat it, but it can be very hard to find once it is no longer shiny or if it’s in tall grass. It is best to install the flags at short intervals. Pin flag carriers or quivers are available in a variety of lengths. Pin flags provide a great visual because they highlight the flow of the trail. They can be especially helpful when creating circular curves in the field.

Re-flagging is necessary on most projects that won’t be implemented within one year. Making an accurate survey of the flagline with a good GPS is essential in order to re-establish the line.

Flagging Tips and Tricks

• Avoid tying flagging on annual vegetation. When the plant dies in the winter, the flagging will be on the ground. Pin flags work better.
• The flags on pin flags will break off quickly in the cold and wind. A trick to make them stay visible longer is to tie a short piece of ribbon flagging around the wire whip just below the pin flags. Use a double overhand knot and tie these as tightly as possible or they will tend to slide down the whip to the ground.
• Don’t tie flagging on poisonous plants.
• In areas with venomous snakes, look before reaching into low brush to hang flags.
• In deciduous forests with dense underbrush, layout in the later fall, winter, or early spring allows better access the topography, view along the flagline and layout, and makes traversing the ground much easier since the vegetation will not be in full bloom during this time period.
• The paper clip trick is great in areas with a lot of thorny plants. They are easier to hang and easier to remove if necessary. One advantage of hanging flags on thorny plants is that the animals will tend to leave them alone.
• If flagging in the winter, hang the flags closer together since new foliage will tend to hide the flags in the spring.
• Team members should be alert for any increase in the buzzing sound or an increase in bee activity since they could be standing on a nest while tying a flag. Be careful if several people are walking in a line. The first person will agitate the bees, the second or third person will likely get stung.
• When flagging along a game or livestock trail, tie flags above or below the browse height of whatever animal is using the trail. Tie flags more often and use double or triple knots.
• Pack a mix of pin flags and ribbon flags, so the appropriate method for a given location can be used.
• If an area is open to firewood cutting, avoid hanging flags on dead trees that would make good firewood.
• When possible, get into the habit of hanging flags at eye height. Then shoot back to check the grade.
• Flags hung on dead limbs or twigs are very visible, but also very likely to end up on the ground after the first winter.
• In cold weather, it’s hard to tie tight knots with cold fingers and cold, brittle flagging. Keep the flagging inside a shirt so it stays warm and pliable. Tight, consistent knots are another advantage of pre-tying the flags onto paper clips.

Section 2: Finding the Way in the Field

Before going to the field, planning and design teams should arm themselves with as much knowledge of the site as possible. They should study maps and imagery for valuable information on the site, where to go, and how to get there. Resource data in GIS layers can show opportunites as well as constraints. Knowing how to use a GPS receiver in conjunction with maps can help the team efficiently navigate to where they want to go and can tell them where they are in relation to the opportunities and constraints. Mapping technology is constantly evolving with more recreation-grade products, higher quality, more features, and lower cost.

Mapping data is displayed as annotated points, lines, and polygons. Features too small to represent as lines or polygons are displayed as point locations (such as a GPS waypoint). While points have no dimensions, they do have coordinates and usually an elevation attribute.

Lines represent the shape and location of geographic objects, such as streams, roads, or trails that are too narrow to depict as areas. Lines are also used to represent features that have length, but no area such as contour lines. Many lines, like GPS tracks, are a series of points connected together with each point having coordinates and an elevation.

Polygons are many-sided area features that represent the shape and location of homogeneous features like land ownership, lakes, ponds, or resource features like vegetative type, soil type, plant and animal habitats, sensitive sites, and other data that is best displayed as polygons.

Each point, line, or polygon should be accompanied by an annotation explaining what the item represents.

Using Topographic Maps in the Field

Topographic (topo) maps illustrate features such as contour lines, mountains, roads, trails, streams, lakes, towns, buildings, power lines, forested areas, open areas, and other features. These features are mapped using aerial photographic interpretation called photogrammetry. In the United States, most of this mapping was done by the U.S. Geological Survey. The entire country is divided into named rectangles and the maps are referred to as USGS quadrangles, or quad maps.

Contour lines are informative features on topo maps and represent points of equal elevation (height) joined together to form a line. Contour lines typically represent elevation intervals of 10, 20, or 40 feet. The exact contour height above sea level is less important than how the lines represent the shape and slope of topography. The closer the contour lines are together the steeper the topography is. Contour lines also illustrate ridges, valleys, and depressions. Convex lines pointing uphill represent valleys or drainages. Concave lines pointing downhill represent ridges or hills. Contour lines that are concentric circles indicate a hilltop. Saddles are flat areas on a ridgeline often between two hilltops. Saddles are indicated where the same contour line on each side of a ridge comes close together without touching. Lines that have small segments at right angles to the contour line represent depressions or sinks and are typically wetlands, lakes, or holes. A contour line ending at the edge of another one depicts a cliff that has height but no width.

Topo maps are useful not only because they show vertical relief as contour lines, but also because they are plotted in a horizontal scale, usually 1:24,000 or 1:50,000. This means that 1 inch equals 24,000 inches (or 50,000 inches). Because topo maps are two-dimensional, the distance is horizontal distance, not slope distance. The slope of the ground or the grade of a trail can be calculated from the elevation difference and the horizontal distance between any two points. As planners and designers become more familiar with contour lines, they will be able to understand slope simply by studying the contour lines. An experienced trail designer can create a conceptual trail alignment by drawing it on a topo map and then refining it in the field.

While topo maps can be used to plot a trail, there are often features such as large rocks and sometimes ledges that do not appear on contour maps. Aerial imagery used in conjunction with the topo map can help identify these features, but often they need to be located in the field, marked on the map, and recorded with a GPS unit.

Topo maps used in conjunction with a compass can be a valuable tool for both orienteering and trail design. Using these tools to find the way and recording the location of features and destinations is useful for both scouting and trail design. A professional typically starts the trail design process in the field by identifying interesting destinations as well as areas to avoid such as wetlands. The key to using a topo map in the field is for the team members to keep track of their position on the map at all times. It is more difficult to determine the location on a map in a remote location than to track how they’ve arrived at that location. The best way to do this is to record a series of waypoints or known locations with a small circle that can also be connected together with a line. The level of effort and detail put into this process will depend on how complex the landscape is, how far from known locations the team is, and how experienced team members are at using topo maps.

The first step in using a topo map is to orient it to north. A compass can be used to determine a north bearing and then rotating the map so the north arrow and vertical grid lines are pointing in the same direction. A compass reads magnetic north while the map usually indicates true north. These two measurements of north are typically a minor issue for basic orienteering, but can be significantly different (20 to 30 degrees) depending on the location in the world. Compasses are engineered for use in general geographic areas, so the team should not use a compass designed for use in North America while designing trails in South America. The team should make note of both the distance measuring units (feet, meters, miles, kilometers, etc.) and contour intervals (feet or meters) to better understand the scale of the map in relation to real measurements on the ground.

Once the topo map is oriented north, use it and the compass to identify a bearing or direction to follow to arrive at another destination. To take a bearing, hold the compass in front with the direction of travel arrow pointing at the destination of interest. Hold the compass level and steady, and rotate the housing dial, until the orienting arrow lines up with the red end (north end) of the magnetic needle, all the while keeping the direction of travel arrow pointed at the destination. Read the number indicated at the index line - that is the bearing. Now follow that bearing to the destination. Use an intermediate landmark along the bearing to look straight ahead and not down at the compass while traveling cross-country. Scale the distance to be traveled and get there by counting double steps. A double step is counting the steps of one foot while ignoring the other (left, right, left equals one double step). Typically one double step is about five feet, so a thousand double steps is about 1 mile in length. Arriving at the destination, mark it on the map and on the ground with flagging material or a pin flag. Repeat this process until the area has been scouted, trail alignment has been designed, or a way has been found. Though today’s technology makes traditional map and compass work archaic, it can be valuable tool in the field because it is dependable.

Topo maps are available as hard copies at most sporting goods and mapping stores. They are also available online, but printing a large format map can be a challenge. The software for many GPS units and other software has the ability to show not only a 2-D view of the topo map, but also a projected 3-D view. This gives a much better view of the landscape and how the trail fits onto that landscape.

Using Aerial Imagery in the Field

While topo maps and other maps are very useful, they still don’t allow a clear visual of the landscape before venturing into the field. Aerial photographs merged into a seamless map are available from several software sources. Some are free, but the ones with highest quality imagery and the best drawing and editing tools are not. With aerial mapping, planners and designers can see the ridges, draws, creeks, ponds, rock knobs, cliffs, vegetation type and density, timber management units, wildfires or fire management units, and other important features.

The most common free aerial mapping is Google Earth and the software for most GPS units can view the tracks and waypoints in Google Earth. While it is primarily used to view data, it can also be used as software to create very basic data by drawing points, lines, or polygons. GIS data can be exported from other software as KMZ or KML files and easily overlaid in Google Earth. Layers exported to these formats can easily be added by clicking on them as an email attachment or as a link on a webpage, or opened from within the program. The end user must have Google Earth software loaded on a computer and have an internet connection for this software to work. Aerial photography and terrain data are automatically loaded into Google Earth if an Internet connection exists. The quality of the aerial photography depends on the area of interest, but it tends to get very pixtelated as the user zooms in.

Another useful tool is the ability to record a flyover path, which can also be shared with others. For example, a recorded path can illustrate the alignment of a proposed trail as a 3-D flyover.

Many of the better GPS units have aerial maps available at a cost from the manufacturer that can be downloaded and used as a base map in the GPS. Assuming that the mapping is current, this feature allows planners and designers to view the landscape not only where they are, but also where they may want to go. They can view a desirable feature on the GPS screen and the unit will give them a bearing and distance to get there. This can be a real timesaver when exploring new ground.

Using GPS Technology

The global positioning system (GPS) is a satellite-based navigation system made up of a network of 24 satellites placed into orbit around the world by the U.S. Department of Defense. GPS works in any weather conditions, anywhere in the world, 24 hours a day. There are no subscription fees or setup charges to use the GPS signal. A GPS receiver or unit is used to receive the information from satellite signals and uses triangulation to calculate the user’s exact location. Essentially, the GPS unit compares the time a signal was transmitted by a satellite with the time it was received. The time difference tells the GPS receiver how far away the satellite is. Adding measurements from a few more satellites enables the receiver to determine the person's position and display it on the unit’s electronic map or as a coordinate such as longitude-latitude. A GPS unit must be locked on to the signal of at least three satellites to calculate a 2D position (latitude and longitude) and track movement. With four or more satellites in view, the receiver can determine the user’s 3D position (latitude, longitude, and altitude). Once the user’s position has been determined, the GPS unit can calculate other information, such as speed, bearing, track, trip distance, distance to destination, altitude, sunrise and sunset time, and more.

Atmospheric and topographic conditions can affect the quality and strength of GPS signals and cause distortions in the data. The location of satellites at given times of the day provide for better or worse signal strength, which affects the accuracy of triangulation. This is typically only important when trying to locate a feature within a foot or two of where it is actually located. Cloudy, rainy, or snowy conditions can have an effect on signal strength and of course lead to moisture build-up in the electronics. GPS signals can be distorted by bouncing off buildings and rock cliffs. When working in areas with tall hard surfaces or in a deep canyon, it may be necessary to use higher quality GPS units that can filter distorted data or switch to the use of a map and compass in these areas. Another technique is to capture a good GPS position from a nearby high point and then measure a bearing and distance from that GPS position. Dense forest canopy can also have a significant effect on GPS signal strength. This can be overcome by using higher quality GPS units or using a combination of GPS, map, compass, and laser range finder. GPS units are usually more accurate after they have acquired GPS data for at least 15 minutes. A good accuracy test for a GPS unit is to see how accurately it is locating a known point such as a road intersection in an open area.

GPS units come in many sizes, colors, and most important price ranges. There is a general correlation between price, accuracy, and functionality. The most commonly used and lower cost GPS units are incorporated into smartphones and tablets. Smartphones formerly only used cellular signals to triangulate location; most now have GPS receivers so their navigation apps can work in remote locations. While these devices are more suited for general navigation purposes, they can be used as GPS units if they are thoroughly tested to make sure they provide adequate accuracy and a reliable signal. GPS accuracy is usually measured in both horizontal and vertical precision. For general navigation and trail design work, planners and designers should find a GPS with an average horizontal accuracy of 3 meters or less. This means the GPS unit will consistently provide an average position within 3 meters or less of the actual location. Accuracy for vertical measurement, or elevation above sea level, is less precise and will usually be within 30 to 100 feet of the actual elevation. A couple of the most important features when shopping for a GPS include the ability to easily download GPS data from the unit and to display topo maps or other imagery on the unit. One of the biggest downsides of recreation-grade units and software is that they don’t allow for large format printing. Only what is shown on the screen can be printed, so making a map involves the laborious process of printing several pages and cutting and pasting them together.

When selecting a GPS unit, make sure it has the ability to connect to a desktop computer or send files electronically. GPS units are very useful tools for a wide range of uses. Some of the most useful functions for trail-related work are provided below.

• Provide an accurate geographic location
• Provide the straight-line distance and direction to a destination
• Record the day’s travel as a track, creating an accurate bread crumb trail to reverse and follow home, or use as backup data
• Provide the altitude within 30 to 100 feet
• Record or refer to destinations as waypoints
• Record or refer to trail alignments as tracks
• Load custom base maps on the GPS, including data such as topo map, slope map, recreation sites, trails, campsites, trailheads, sensitive areas, private property, etc.

A conceptual trail design alignment can be completed on a desktop computer and then loaded on the GPS unit. The loaded alignment can be used as a reference line while refining the trail design in the field.

Smartphones and some GPS units geotag digital photos, which can be used to document the location of trail alignments, features, and scenic views.

Video and voice recordings can also be geotagged to provide more detailed documentation of trail designs and conditions for construction and maintenance purposes. If a video is geotagged to an entire trail GPS line, a split view of a map and video can be used to illustrate a trail design or existing trail. This provides a virtual tour of a trail before it’s constructed.

Geotagging records a GPS coordinate within the header data of a jpeg photo. Software such as GeoJot can be used to create GIS points from this geotag information, which can then be illustrated on the GPS for future field work or on maps. GeoJot software can also be used to geotag photos from standard digital cameras using a GPS track or track log. There are digital cameras such as the Ricoh GPS camera that can assign location attributes to photos. This type of camera greatly improves efficiency and quality of digital photography.

Transferring files from a GPS to a computer used to be difficult. While there are many kinds of files used by GPS units, there are now free tools such as the Minnesota DNR Garmin GPS tool and the GPS Bable tool available to convert between these types of files. ESRI ArcGIS software also imports and exports to the most common types of GPS files, including GPX files.

GPS units are wonderful tools but they are electronic and need to be carefully managed. One of the larger risks in using a GPS is actually losing the GPS after it’s been used to capture data. If the team is working on a multiday backcountry trails project, team members should find a solution to back up the data at least once a day. The best way to back up GPS data is to email it to someone so that it’s saved on an email server. If the team won’t have Internet access on a daily basis, it should use a laptop and a USB memory device to back up the data. While all GPS units are designed to be more rugged for field use, treat them like a fragile instrument and they will perform more reliably. Always have three times more battery power than needed. For 100% reliability, bring two identical GPS units that are equally ready for field work and bring a paper topo map and compass also.

Finding a Line on the Map in the Field?

I have a line on a map, but how do I find that line in the field?

If the line is of a file type that can be loaded into the GPS, navigate to any point on that line in the field using the GPS. It becomes more difficult when the line is only on the map and not loadable into the GPS. When there is dramatic relief with well-defined ridges, draws, peaks, etc., it is relatively easy to orient on the ground in relation to the map. This becomes more difficult in flatter terrain and in dense vegetation with limited visibility, but if the GPS is loaded with the same map data as the topo map, the contour lines shown on the GPS screen will be identical to the ones on the topo map making it quite easy to pinpoint the location.

With a GPS, team members can move the cursor to where they want to go and the display will show the bearing and distance to get there. As they walk, the distance will become shorter. As long as they have a good satellite signal, the GPS will lead to the destination.

Many units have a built-in compass. This can be handy if it is calibrated. If locations are changed often, it will need to be re-calibrated at each location. Even at that, sometimes the readings are erroneous, so it is usually best to verify the calibration with a hand compass.

Section 3: Applying Engineering in the Field

Before going to the field, planners and designers need to be able to measure grades and apply basic engineering principles to measure or calculate lines, areas, and volumes.

How to Measure Grade

There are three primary methods of measuring grade in the field. The first is the two-person method. On flat ground, two people stand toe-to-toe in front of each other. Using a clinometer or Abney, one person puts the bubble on zero percent and notes the spot where that hits his or her companion (chin, tip of nose, hairline, etc.). That spot becomes the height of instrument (HI) point or zero point on the partner. Sighting on that same spot as the partner moves up and down the slope will give the percent of grade difference between the two people.

The second method is the HI rod method. Take two rods, sticks, or lath of equal length. If there are two people, have one person hold one rod stationary and vertically level while the other person moves up or down slope. If there is only one person, pound one rod into the ground just far enough so it will stand by itself. Put the other rod next to the first and mark the spot where the second rod is level with the top of the first or stationary rod. The first person moves up or down slope with the second rod. That person uses a clinometer or Abney to shoot between the mark on the top or the level marking of the first rod and the second. The result will be the grade difference between the two rods. On flat ground, up or down slope can be visually deceptive. Don’t guess. This method is foolproof.

The third method is the one-person method. At a starting point, tie a short flag at eye height on a tree limb or brush (this becomes the HI flag), move ahead and up or down the slope as needed, sight back at the HI flag with the clinometer or Abney and the result will be the difference in grade or slope between the person and his or her starting point. This method does not work well in open areas where there is no vegetation at eye height or in places with very dense vegetation where the HI flag can quickly become obscurred.

How to Find the Lowest Point in a Grade Sag

On very flat ground or when trying to determine the low point of a drain, the HI rod method works very well. It is usually best to mark off elevation lines on the stationary HI rod and create a makeshift leveling rod. Take a tape measure and make a short dash at 1-inch intervals with a magic marker. It is best to use a hand level or Abney level set on zero because these are more accurate than a clinometer and they usually have magnification in the optics for easier reading. In the example to the right, sight #1 is below the top of the stationary rod, so elevation has been dropped. Sight #2 is below sight #1, so elevation is still dropping. Sight #3 is above sight #2, so elevation is now rising. Go back to the area of sight #2 and take a couple more shots at the stationary rod. The lowest reading or sight point on that rod will be at the low point of the trail.

How to Lay Out a Circular Curve without Instruments

A lot of work field technicians do is conducted without assistance, so to make effective use of time, they need to be able to perform basic engineering applications by themselves. As discussed in Chapter 4, circular curves provide improved flow, increased rideability, and reduced tread impacts. There are times when it is essential that the curve be circular such as when designing a climbing turn. These types of turns are the most effective way to gain elevation on a motorized trail, but they must be smooth, flowing, and circular; or significant tread impacts can develop.

Any two points make a line and any three points can make a curve; that same progression can be applied in the offset method to make a curve. It is best to practice this technique in an open field with good visibility. At the starting point of the curve (called the PC or Point of Curvature), insert a pin flag or lath into the ground. This is point one.

Walk ahead 15 feet (x) staying on line between point one and the tangent behind it. From that point, measure 5 feet (y) in the direction the curve will go and insert another pin flag or lath at that offset point. This is point two. Walk ahead another 15 feet staying in line with points one and two. From there, measure 5 feet in the direction of the curve and insert another pin flag or lath. This is point three. A degree of curvature for the curve has now been established.

Planners and designers can now visualize how the curve is taking shape. They can continue this process until the curve is completed (called the PT or point of tangency). They can add intermediate flags as needed between points and adjust any that look out of place.

To make a tighter curve, increase (y) or increase (y) and decrease (x). Once planners and designers have practiced this technique, they can use steps or paces instead of measuring the distances. When they have mastered the technique, they will be able to lay out any curve using just flagging and their eyes.

Another method for laying out curves is the radius method. For this method, the radius (r) of the curve is known. If it isn’t known, estimate the radius that will fit the site and then adjust it up or down as necessary. For example, assume a 25-foot radius is needed. From the starting point or PC, turn 90 degrees to the back tangent and measure 25 feet in the direction of the curve and insert a pin flag or lath. This is the radius point of the curve. From this point, measure out 25 feet and insert pin flags along the arc of the curve. If trees or brush are in the way, make several arc measurements. Add intermediate flags as needed between points and adjust any that look out of place.

Geometry 101

In the field, team members need to know how to make three types of calculations: perimeter (P) or circumference, area (A), and volume (V). It is important to note that in making any of these calculations, all values must be expressed in the same units, i.e., feet times feet, not feet times inches.

How to Measure Perimeter

The perimeter is the distance around the border of a flat 2-dimensional shape. The distance is a linear measurement commonly represented as inches (in), feet (ft), yards (yd), or miles (mi).

Example 1. A safety training area has been constructed and now a log and bunk barrier needs to be put around the perimeter to control access and dress up the site. The facility is rectangular in shape, 350 feet long and 250 feet wide; how many feet of barrier are needed?

P = 2(Length + Width) or 2(350’ + 250’) or 2(600’) or 1,200’ of barrier

Example 2. Adjacent to the training area is a circular tot lot and a barrier is needed around that also. The tot lot is 165’ in diameter; how many feet of barrier fence are needed?

P = 2π(radius) or π(diameter), so P = 3.1416(165’) or 518’ of barrier

How to Measure Area

The area is the measurement in square units of the size of the surface within the border of a flat 2-dimensional shape. The square units are commonly expressed as square inches (in²), square feet (ft²), square yards (yd²), square miles (mi²), or acres (ac²). There are 9 ft² in 1 yd² and 43,560 ft² in 1 acre.

Example 3. During the planning for a safety training facility, the number of acres that would be impacted has been determined. The entire site is rectangular in shape, is 780’ long and 565’ wide; what is the area?

A = l x w = 780’ x 565’ = 440,700ft²
A = 440,700ft²/43,560ft² per acre = 10.12 acres

How to Measure Volume

The volume is the measurement in cubic units of the amount of space occupied by a 3-dimensional shape. The cubic units are commonly expressed as cubic inches (in³), cubic feet (ft³), or cubic yards (yd³). There are 1728 in³ in 1 ft³ and 27 ft³ in 1 yd³. The volume is generally the area of the base of a geometric shape multiplied by the depth or height.

Example 4. The surface of the tot lot is rocky and 8” of good dirt is needed to pad over it. How many cubic yards of dirt are needed? Since the tot lot is circular and the floor of that circle is going to be raised, a cylindrical shape is created where the volume is:

V = πr²x h

First, convert the diameter of 165’ to the radius by dividing it by 2. Then convert 8” to decimals of a foot by dividing 8” by 12.
V = 3.1416(165’/2)² x (8/12)
V = 3.1416(82.5’)² x (0.667’)
V = 3.1416(6806.25ft²) x (0.667’)
V = 21382.52ft² x 0.667ft
V = 14262.14ft³

Convert cubic feet to cubic yards by dividing by 27
V = 14262.14/27
V = 528.23yd³

Note: This is a compacted-in-place volume or compacted cubic yards. The dirt or gravel that comes in the truck is loose cubic yards (cy). If 528 cy of dirt are ordered, there wouldn’t be enough, so a compaction factor is applied. Many material sources already calculate this, but if not, a compaction factor will generally range from 25 to 33%. For this example, the compaction factor is 25%. That means that 1 cy in the truck will yield 0.75 cy compacted on the ground, or that 1 in-place cy = 1.333 loose cy (1/0.75). Multiplying 528 cy in place by 1.333 will yield the loose cubic yards to be ordered.

V = 528 x 1.333 = 704cy loose

Example 5. Due to the soft soils and high volume of traffic anticipated on the trail from the parking lot to the training area, the trail needs to be hardened with 6” of crushed rock, which will be watered and rolled with a vibratory roller. The trail will be 480’ long and the finished tread will be 9’ wide with the rock sloped at 3:1 down to the subgrade. a) How wide does the subgrade need to be made before the rock is put on it? b) The rock is sold by the ton and 1 cy of this rock weighs 3,350 lbs. How many tons of rock are needed?

At a 3:1 slope, it takes 18” of run to gain 6” of rise, so Y = 18” or 1.5’.
X = 9’ + 1.5’ + 1.5’ = 12’ subgrade

Then, calculate the number of cubic yards needed. Looking at the end view of the trail prism, there are three geometric shapes: a triangle, a rectangle, and another triangle. These shapes can be combined so that there is one simple shape by taking the triangle on the right and putting it on top of the triangle on the left, making one rectangle.

The area of a rectangle is L x W
A = 10.5’ x 0.5’ = 5.25ft²

The volume equals the area of the base times the height, which in this case is the length of our trail.
V = 5.25ft² x 480’ = 2,520ft³

Divide by 27 to convert cubic feet into cubic yards.
V = 2,520ft³/27 = 93.33cy

Again, this is a compacted in-place volume, which needs to be converted to loose cubic yards. Since this rock will be mechanically compacted, it can be assumed that the compaction factor will be 30%, so 1 cy in the truck will yield 0.7 cy on the ground. 1/0.7 = 1.429 compaction factor.

V = 93.33cy x 1.429 = 133cy loose

The rock is sold by the ton and 1 cy weighs 3,350 pounds
T = 133cy x 3350 lbs per cy = 445,550 lbs/2000 lbs per ton = 223 tons to order

Trigonometry 101

Trigonometry is the study of triangles and the relationships between their angles and the length of their sides. With sines, cosines, secants, and tangents, it can get quite involved, but there are a few basic theorems and relationships that field technicians should know.

Understanding Triangle Types

• A triangle is a geometric shape with three sides and three angles
• A right triangle has one angle that is 90^°
• In an equilateral triangle, the length of all three sides and all three angles are equal
• An isosceles triangle has two equal sides and two equal angles
• A right isosceles triangle has two equal sides and the angle between them is 90^°
• A scalene triangle has no equal sides and no equal angles
• A right scalene triangle has no equal sides and no equal angles, but one of them is 90^°
• The longest side of a triangle is called the hypotenuse. In a right triangle, the hypotenuse is opposite the 90^° angle.

In all triangles, there is an interrelation between the three sides and the three angles. Listed below are some of the key relationships that can help solve problems and determine quantities in the field.

In any triangle, the sum of the angles equals 180°; a + b + c = 180°. Therefore, in an equilateral triangle all three angles are 60°. In a right isosceles triangle, the three angles are 90°, 45° and 45°.
In any right triangle, the sum of the squares of the two sides equals the square of the hypotenuse; a2 + b2 = c2. This is also referred to as the "3-4-5 Rule", where a=3, b=4, c=5.
In any right isosceles triangle, the angles are 45°, 45°, 90° and the relationship between the sides is 1x : 1x : x√2 where x√2 is the hypotenuse.
In any 30°, 60°, 90° triangle, the relationship between the sides is 1x : 2x : x√3 where 2 is the hypotenuse.
In any equilateral triangle, the angles are 60°, 60°, 60° and the relationship between the sides is 1 : 1 : 1.
If a vertical line is drawn from the top angle down to the base, the equilateral triangle is split into two equal 30°, 60°, 90° triangles.

Using Trigonometry to Calculate Area and Distance

Example 6. One corner of the training area has some shade trees and this area needs to be blocked off with barriers and some picnic tables installed. The trees end about 75 feet from the corner of the training area; how long does the barrier need to be?

The barrier will create a triangle with two equal sides and a 90◦ angle, so this is a right isosceles triangle. From the information in the table above, it is known that the relationship between the sides is 1x:1x:x√2 where the √2 is the hypotenuse. The equal sides have been multiplied by 75 or 75x1, so the hypotenuse needs to be multiplied by 75 or 75x√2.

X = 75(√2)
X = 75 (1.4142)
X = 106’ of barrier

This can also be solved using the relationship of a2+b2 = c2.
752 + 752 = c2
5625 + 5625 = c2
11250 = c2

To find c, take the square root of c2 or √c2. In an equation, what is done on one side must also be done on the other side
√11250 = √c2
106 = c

Example 7. To reduce dust, bark chips will be spread over this area, and the supplier said that 1 cubic yard covers about 85 square feet. How many cubic yards of bark chips are needed?

The area of a triangle equals one-half of the base times the height: A = 1/2bh. The base equals 106’. By dropping a vertical down to the base, two equal isosceles right triangles are created with the relationship of 1x:1x:x√2 where x√2 is the hypotenuse and x = 53’; therefore h = 1(53) or 53’.

The area of the original triangle then is:
A = 1/2bh
A = ½(106’)(53’)
A = 2,809 ft²

To find the number of cubic yards of bark needed, divide 2,809 ft² by 85 ft² covered per cy of bark.
cy = 2809/85
cy = 33 cy bark chips are needed

Example 8. The existing parking lot is a square shape and vehicles park in a jack-strawed fashion so there are safety concerns, plus the space doesn’t get fully utilized. The parking situation needs to be assessed for options. A pull-through design has better flow and space efficiency and these are generally designed with a parking angle of 30◦. Many of the visitors come for the weekend and have pickups and large toy haulers, so the parking lot needs to accommodate a vehicle that is 65’ long. Room is needed for the loading ramp to come down, 8’, and to unload without getting into the travel lane, another 8’, so the total length of each parking stall needs to be a minimum of 81 feet. A few feet are added for a margin of safety, so 85’ is used for the stall length. If a 14-foot travel lane for ingress and egress is desired, how wide would the parking lot need to be?

To find the width of the parking lot W, the height of the triangle H must be found, then the two 14’ travel lanes can be added. Angle a is 30^° and there are 180^° in every triangle, so angle b must be 60◦. Therefore, there is a 30^°/60^°/90^° triangle and the relationship between the sides is 1x:2x:x√3 where 2x is the hypotenuse.

If 2x = 85’, then 1x = 42.5’, so X = 42.5’.
H = x√3 = 42.5√3 = 42.5(1.732) = 73.6’

To find W, add in the width of the ingress and egress lanes.
W = H + 14’ + 14’ = 73.6’ + 14’ + 14’ = 101.6’ of parking width needed

Example 9. An existing trail is being assessed and the work necessary to make the trail more sustainable is being staked out. In one place, the trail dips into a shallow ravine to cross a small creek. The ravine gets muddy in the spring and riders heavily braid the trail trying to get around the mud hole. The decision has been made to install a culvert and raise the trail grade by placing a rocky fill across the ravine. How long does the culvert need to be?

Using a hand level and a makeshift leveling rod, it has been determined that 3ft 10in of fill will be needed where the culvert will be placed. The trail is 50” wide, but 1ft of fill widening is to be added when a fill height exceeds 18”. Since this will be a through fill, there will be 1 ft of fill widening on each side, so the total trail width over the culvert will be 74”. To convert that to feet, divide by 12.

74” ÷ 12 = 6.17’

To convert the fill height to feet, divide 10” by 12 and add 3’.
10” ÷ 12 = 0.833 + 3’ = 3.833’ of fill

With a fill slope of 1.5:1, there is 1.5ft of run for every 1ft of rise, so Y = 3.833’ x 1.5 = 5.75’

The length of the culvert then will be 5.75’ + 6.17’ + 5.75’ = 17.67’ = 18’ minimum

If rock headwalls are desired, then another foot of length could be added to each end for a total culvert length of 20’.

Do I really need to know this?

It depends on what project work you need to do in the field. Sure, there are software programs that do all of these calculations, but a) do you have that software in the field? and b) do you understand what that software is doing for you? If you are managing a project and the equipment is running and all of a sudden you need to make a change that will require more materials, will you have the skills to make quick decisions and quick calculations so the work doesn't have to shut down? If you have to make a design decision like the parking lot example, do you have the tools to assess the feasibility of that decision?

Section 1: Geosynthetics 101

Geosynthetics Defined

Geosynthetics are synthetic polymers that are woven or formed into a variety of shapes. These materials perform six major functions: reinforcement, separation, drainage, filtration, containment, and erosion control. The first four functions are most commonly used for trails and are explained below.

The tough polymer fibers give the geosynthetics lateral and longitudinal tensile strength, which provides reinforcement and helps prevent deformation under a load. This tensile strength distributes the load over a wider area reducing the PSI of the load and improves the weight-bearing capacity of the material above it. Since the geosynthetic supports much of the load with little deformation, less force is directed down into the layer of soft soil resulting in less displacement and less subsoil pumping. The geosynthetic acts as a structural bond between the good upper layer and the poor lower layer, which increases the weight-bearing capacity of both layers. Using a geosynthetic or a geosynthetic layer can reduce the amount of fill needed on a tread surface, saving costs and maintenance in the long-term.

A layer of geosynthetics is used for separation and prevents good material, like crushed rock, from intermixing with poor material, like soft or saturated soil. For example, many times rock is placed in a mud hole but in a couple of years it has disappeared. When moisture conditions are right, the rock gets pushed into and absorbed by the soft soil. Geosynthetics provide important separation of and reinforcement between the layers of rock and soil.

Some geosynthetics are used for drainage and designed to allow water to drain laterally across them so water is diverted off to the sides rather than down, which reduces the saturation of the subsoil and increases its strength.

Some geosynthetics are used for filtration and designed to allow water, but not soil, to pass through their pores. It is this filtration property that makes silt fence and French drains so effective.

Common Geosynthetics Shapes

The most common geosynthetics shapes are: geotextiles, geogrids, geonets, geocells, grass pavers, and geocomposites.

Geotextiles are synthetic fabrics that are most commonly used for separation, reinforcement, and filtration. These are great for OHV trails because they allow water but not soil to seep through and their tensile strength can support heavier loads.

Geogrids are polyethylene strands that are bonded into a grid pattern like a fish net. They are heavier and less flexible than geotextiles and therefore provide a higher level of reinforcement. They are often used in retaining walls and buttresses for added strength and shear resistance. For OHV trails in wet areas, geogrid is often put down over a layer of geotextile fabric and topped with a layer of coarse rock. This combination provides a superior level of separation and reinforcement.

Geonets are a composite consisting of a thick geogrid sandwiched between two layers of geotextile. Because there are two layers of fabric, they provide excellent separation and reinforcement, but they are primarily designed to allow water to flow through the center grid and off to the side of the trail.

Geocells are polyethylene strips that are bonded into a honeycomb shape. They come in a variety of thicknesses, and are shipped flat for easy transport and then expanded on site. Once expanded, the honeycomb is filled with good soil, rock, or a mixture, which is then compacted. The cells contain the material so it can’t displace out to the sides and each cell provides increased load-bearing and rigidity. The primary function of geocell is to provide reinforcement, not separation, so when it is used in a wet area with saturated soils, a layer of geotextile is put down first to provide the necessary separation.

Grass paver is a category of very stiff panels that can provide cellular containment like geocell but has a partial bottom that gives it excellent reinforcement properties. The panels interlock, which helps to distribute the load, reduce PSI, and stabilize the structure. Lightweight and easy to use, this is the one category of geosynthetic that is designed for direct tire contact.

Geocomposites such as sheet drains have a large cross section that allows drainage. If geotextiles are placed under the trail tread, the sheet drain should be oriented with the geotextile on the bottom and the plastic core on top. This orientation reduces the amount of fill needed.

Here are some key points on geosynthetics:

• The need for any structure requiring a geosynthetic is a potential red flag indicator of poor trail location. Explore other options first, if available.
• Some geosynthetics are not UV stabilized so they deteriorate when exposed to the sun. Check specifications before purchasing and store them in their original wrappers out of sunlight.
• Ensure that the fill material covers the entire top and sides of these UV sensitive geosynthetics and is maintained at this level. Geosynthetics are tough, but most are not designed or intended to be used as the tread surface. Forces from the tires will quickly break down the material, tear it, and displace it.
• When used for trail hardening, the geosynthetic installation must be wider than the designed trail width. The more the load is centered, the more effective the weight-bearing will be. This keeps the tires off the shoulders of the installation, which protects them from displacement.
• Because of its reinforcing property, less fill is needed with a geosynthetic to attain the same weight-bearing capacity as a fill without it. This reduces the amount of material that needs to be hauled in and reduces the cost of the installation.

Section 2: Soil Stabilization Techniques

Just as gardeners treat the soil to add nutrients and organic matter, trail designers can fortify some soils to add structural strength. The intent is to give the soil the ideal clay content for binding and the ideal rock content for load-bearing strength. Benefits include increased strength to withstand heavy traffic pressure (reduced displacement), reduced sedimentation (soil loss), and increased intervals between heavy maintenance operations. Another advantage of stabilization is that in most cases, the trail retains its natural appearance and character, which enhances the rider experience. Designers should consult with an engineer, geologist, or soil scientist to determine the best treatment for a particular soil. The amendment process is simple: excavate the top layer of the tread, mix in the amendments usually with a rototiller or similar machine, spread the mixture back out onto the tread, add water if available, and compact it with a roller. Adding a layer of geosynthetics between the original soil and the treated soil will further increase the durability of the trail.

Soil Stabilization Materials

There are five common types of soil stabilization materials: clay, lime, aggregate, mix, and chemical.

A non-cohesive soil is one that has a low clay content. One way to remedy that is to add clay as a binder. This will not work for fine-grained soils like sand because the clay adds binder, but not load-bearing capacity. However, if the soil is course-grained with a high rock content, just adding clay can work quite well. There can be a fine line between not enough and too much clay, so getting the right mix is important but hard to control in the field.

Lime has long been used to stabilize wet soils, especially wet clay soils. It dries the soil, bonds it together, and increases its load-bearing capacity. It has been successfully used under roads, runways, and building foundations, but there is little documentation on its use on motorized trails.

Some soils have a high clay content, but not a high rock content. Adding aggregate, which binds with the clay, increases the structural strength of the soil. Crushed rock works the best because it is highly angular and the rock points tend to lock the rock in place, but other rock can work also.


For non-cohesive fine-grained soils like sand or pumice, the soil lacks clay and rock content, so amending the soil with a mixture of clay and aggregate can work quite well.

A variety of chemical products are available which provide dust abatement by stabilizing the tread surface. Some are salts like magnesium chloride and calcium chloride and some are polymers like Road Oyl®, Soiltac®, Envirotac®, and Soil-Sement®. To be effective on trails, these products cannot be applied topically and must be disked or rototilled in for deep penetration. While there have been some studies of chemical stabilization for accessible trails, there has been limited testing of its use for OHV trails.

Here are some points regarding soil stabilization:

• Even with a mix design from a specialist, field application and mixing methods are crude at best and consistency is difficult to attain.
• The application and mixing is labor and equipment intensive and thus expensive.
• Because of the cost, a common mistake is making the stabilized soil layer too thin. Tire action can quickly break through it creating potholes and maintenance equipment can quickly wear it away. Minimizing the design to save money is a false economy.
• Unlike a road, runway base, or building foundation, trails have roots and rocks. In order to obtain a uniform depth and consistent mix, those need to be taken out, which adds to the cost and detracts from the naturalness of the trail.
• If chemicals are being considered, check for regulations that prohibit or restrict their use. A permit may also be required.
• When considering a project, check with local road or trail authorities to see what their experience has been. There may be a local mix or a local material that has exceptional qualities.
• Don’t be afraid to experiment.

Section 3: Trail Hardening Techniques

Gravel and Stoning Reinforcement

Often the easiest and cheapest way to harden a wet spot or a soft spot is to simply add rock to it. A well-graded crushed rock works the best since the fine components fill in the voids between rocks and the crushed angles lock the whole mass together. Because crushed rock binds together so well, it is more impervious to water, which helps prevent the further saturation of the underlying soil layer. Most times people use whatever material is readily available to save cost. That’s okay, try it and see how it works. Typically, the rock should be 3 - 4” or less. Anything larger than that can be too rough to comfortably ride with a motorcycle, but may be okay for ATVs, ROVs, and 4WDs.

Stoning works well in soft non-cohesive soils and in seasonal wet areas. It does not work in perpetually saturated soils. Stoning provides a host of benefits: a) it provides both bearing and binding for increased weight capacity and decreased rutting and displacement; b) it reduces or eliminates trail widening or braiding by creating a firm trail tread; c) it protects the underlying soil layer from erosion thus reducing sedimentation; d) it has a rough surface and doesn’t form rills so it reduces the velocity of the surface water, which makes it easier to drain water off the trail; and e) being more durable, it increases the interval between required tread maintenance.

On the negative side, stoning: a) reduces the naturalness of the trail and detracts from the rider experience; b) can conflict with the aesthetics of the setting, especially if the rock color does not harmonize with the landscape; c) can cover up roots and rocks that are challenge features; d) can increase speed and therefore decrease seat time; and e) in wet or clay soils, can gradually sink in and need replacement.

Other Trail Hardening Materials

There are seven other commonly used materials for trail hardening: cobble reinforcement, geotextile fabric, grass pavers, geocell, pavers, slab rock armoring, and tire mats. There are also inventive materials or "others".

Cobble reinforcement is similar to stoning except it uses rock that is 6 to 10” or less in size. Cobbles work well because they have a large surface area for increased load-bearing and that surface area also reduces the tendency of wet soils to suck the rock down into oblivion. Because cobble rock is usually uniform-graded, the voids between the rocks allow water to run through them, thus providing load-bearing as well as drainage. This is why cobble rock is used in drains.

In wet, mucky areas, cobble rock is often put down first, worked into the ground, and then covered with a layer of smaller-sized gravel. This allows water to drain through the rock subsurface, but the tread surface is smoother. The combination has less displacement since a mix of particle sizes holds the tread surface together.

When soils are wet more frequently than seasonally or if they are saturated, any applied gravel or cobble will eventually get sucked down into the soil and disappear. In this case, a layer of geotextile fabric will provide separation of the wet and dry layers and provide reinforcement by distributing the load over a wider surface area. This technique is simple, effective, and probably the most widely used trail hardening method.

Grass pavers can be placed directly on the surface with sandy or wet soils or placed on a layer of geotextile in saturated soils. The geotextile provides separation and additional reinforcement. Some varieties of grass pavers are the only geosynthetic that can take direct tire contact. It can be used as is or covered with a layer of fill for additional support and a more natural appearance. When placed directly on the surface with no geotextile or fill layer, the holes in the bottom of the panel allow vegetation to grow up through the panel. This results in less site disturbance, increased soil stability since the root zone is not disturbed, and increased visual appeal. The panels can be easily cut in the field to create curves or irregular shapes. Geoblock® is a grass paver often utilized for OHV trail hardening.

Geocell is commonly used for retaining walls and other support structures like bridge abutments. It is available with perforated or non-perforated cell walls.It has been used for trail hardening, but many of those installations have failed due to the lack of maintaining an adequate layer of fill. Geocell will disintegrate if exposed to direct tire contact.

Pavers include concrete blocks and cinder blocks. When installed properly, these are tough, durable, and can withstand direct tire contact. The concrete edges provide traction, so pavers can be used on very steep grades. They are heavy, so transport into the site can be a challenge, and their installation is labor intensive, but pavers are one of the most commonly used trail hardening methods.

There are as many examples of poor installations using pavers as there are of good installations, but here are three points to ensure success with pavers:

1. The pavers must lay on a smooth, even surface. The bedding could be compacted native soil if it is a cohesive soil that won’t displace. Compacted gravel will provide a firm bedding and bearing for the pavers. If the soil is always wet, a layer of geotextile can be put down under the bedding material to provide separation and reinforcement. Roots, rocks, or any surface protrusions can cause a paver to break or move.
2. When pavers are allowed to move, the installation will be doomed to failure. They must be thoroughly anchored or confined in place to prevent movement. It is easy to assume that since they are so heavy, they will never move.
3. In some soils, such as non-cohesive soils like sand, pumice, or wet muddy soils, the pavers are likely to move even if they are pinned. Also, factors like the grade and alignment can affect the forces being placed on the installation. A 100’ stretch of pavers on a 35% grade exerts huge downward forces on the bottom pavers and enough force for the installation to eventually blow out at the bottom. The best, most durable, and longest lasting installations are divided into sections and are confined on all sides with logs or preferably 4x4 or 6x6 treated timber that is pinned in place. Each section performs independently and has no impact on the others. Downward and lateral forces are controlled and contained and the pavers cannot move. An additional benefit of framing is that the edges are supported and protected. This helps prevent breakage. As soon as breakage starts to occur, movement will soon follow.

Depending on the availability of materials or access to the site, flat flagstone-type rocks or other materials can be used to harden short sections of trail. As with pavers, proper bedding and prevention of movement are essential.


Recycled tire mats have been available in some fashion for many years. Though using recycled material is good for the environment, the mats to date have not held up well to the forces of OHV use.

Trail hardening can be expensive, but there may be local sources of materials available for free that might work quite well. Don’t be afraid to experiment. Trying something and having it fail may be disappointing, but it’s probably still better than doing nothing at all.

Here are some things to consider about trail hardening:

• Product manufacturers can assist in product selection, application, and design specifications.
• A key consideration before installing any trail hardening is how it will be maintained. A relatively thin layer of fill over a structure requires awareness and a light touch by maintenance workers, especially when using equipment.
• It is also critical that the layer of fill over a structure be maintained at the designed depth to prevent exposure and damage to the material underneath.
• In areas with limited trail access points, another consideration is how maintenance equipment will be able to get from one end of the installation to the other without damaging the structure. If the maintenance equipment is a trail dozer with steel tracks, what will that do to pavers or grass pavers without a layer of fill?
• Placing heavy angular material directly on top of geotextile can tear the fabric and affect the integrity of the structure.
• Don’t be afraid to experiment with unusual or locally available materials or methods.
• Trail hardening projects can be labor and equipment intensive so they can provide great opportunities for volunteer work parties or for creatively seeking new partnerships for the task and project.
• Depending on the soils, reducing speed and increasing the flow of the trail by changing the alignment can reduce the need for hardening in some situations.
• Trail hardening is often seen as a “fix” for steep grades and excessive erosion, but the forces at work need to be understood. Tire action and displacement is one, but water volume and velocity is the other. Hardening does little to manage the water, so it is essential that as much water be removed from the trail as possible before the water gets to the installation.
• It may be better and less expensive in the long run to move a trail instead of hardening it.

The Good...

The Bad...

The Ugly...

Section 1: Water Control Structures

An essential key for a durable trail is managing water. Structures help drain water off the trail, allow water to flow under the trail, help raise the trailbed above the ground water level, drain water across the trail, and drain it away from the trail; all of which help manage water.

Draining water off the trail.

There are several ways to help get water off the trail: rolling dips, outsloped sections or kinks, and waterbars.

Rolling dips are man-made grade reversals constructed on existing trails with long sustained grades or steep grades to reduce the size of the tread watershed. They are also used in new construction where there is no other opportunity to reverse grade to provide drainage. The key to good rolling dips is just that, keep them rolling.

Here are some general points about rolling dips:

• Any man-made structure requires maintenance. A rolling dip will never be as effective and as maintenance free as a grade reversal.
• Rolling dips must roll. The shorter the distance from the sag to the crest, the more abrupt and less functional the rolling dip will be. If it feels like a rider will fall into a hole when riding, the dip is too short.
• The structure will fail more rapidly in non-cohesive soils like sand or cobble rock or a sand and rock mix.
• Armoring a rolling dip with mechanically compacted crushed aggregate will increase the effectiveness and longevity of the rolling dip by: a) reducing the velocity of the water so it can be more easily diverted off the trail; b) hardening the trail tread to reduce rutting; and c) protecting the crest from displacement.

When controlling water with rolling dips:

• Use the trail alignment to help turn the water. Place the structure either on a tangent, or better yet, on a curve that turns in the direction the water should go. Trying to turn the water in the opposite direction of the curve will usually result in failure.
• Locate the rolling dip where there is a break or flattening in the grade. This will help slow the water down so it can turn and flow off the trail.
• Drain the water off the trail before the grade and after the grade, not mid-grade.

Rolling dips and grade considerations:

• Avoid installing rolling dips mid-slope on grades over 15 percent. The approaches become too steep and riders lose most of their momentum. Riders must roll on the throttle to get going again, which results in tread impacts and increased maintenance.
• On steeper grades, rolling dips can invite riders to make jumps out of them.
• Generally, as grade increases, tread watershed size increases, or soil quality decreases; the spacing between dips needs to decrease.
• As the grade increases, the transitions into and out of the rolling dip must proportionally increase.

An outsloped section or knick is a short piece of trail that has been steeply outsloped at 8 to 10 percent or more to provide drainage. These are best used in grade sags or flat low areas that tend to puddle water. The difference between a knick and a rolling dip is that there is no sag and crest in a knick. Instead, a section of the trail is cut away in a “C” shape and the excavated material is removed from the site. A dip forces water off the trail while a knick allows the water to run off the trail. Knicks can be effective on flatter grades up to about 5 percent, but on anything steeper, too much outslope is needed to turn the water. In these situations, riders will tend to hug the uphill side of the trail, and water carried by tire ruts will soon deform and breach the structure. Rolling dips are a far better alternative. Waterbars are shallow structures that are used to drain water off the surface of a trail or road. They can be made out of a combination of rubber belts, logs, rocks, treated timber, or dirt. They are usually installed at about a 30 degree angle so that water will hit the structure and be directed off the trail. As a drainage structure on a motorized trail, none of these are effective because they are too abrupt and they fail due to the tires rolling over the structure. Logs are slippery at an angle and dislodge, rocks become dislodged, and dirt gets displaced. Though widely used historically, they are now being replaced with rolling dips, which are far more effective.

A belted waterbar has a piece of conveyor belt sandwiched between two 2”x 6” treated boards. The belt sticks up out of the boards a minimum of 6” and the structure is buried in the trailbed so that only about 3” of the belt protrudes above the surface. The belted waterbar has long been thought to be an effective drainage structure option for wheeled trails, but that has not proven to be the case. The main reason for their failure has been misuse of the structure.

There are six main reasons why waterbars fail:

1. Most belted waterbars are not constructed properly and have too much exposed belting, which becomes ripped or flattens over and becomes slippery.
2. Most installations are not long enough and invite riders to ride around them.
3. Most are not installed in the proper location where the trail alignment or grade will help them work.
4. Many have been installed on a fall line trail in an effort to make a non-sustainable trail more resistant to degradation. Waterbars can be an aid in some situations, but not a cure-all. Other options like relocation should be considered first.
5. Many have been installed on excessive grades (hillclimbs) and the tires damage them or water rushes over them.
6. Lack of maintenance. Any man-made structure requires maintenance and eventual replacement. Waterbars require frequent maintenance.

The fact is that the need for any waterbar is a red flag indicator of a bigger problem. Water is running down the trail due to excessively steep grades, excessively long grades, excessively large tread watersheds, or failure to recognize and seize other drainage opportunities. Rolling dips are a better option, but in most situations, the best long-term solution is trail relocation.

Draining water under the trail

Several structures are available to help direct water under a trail, including bridges, arches, culverts, headwalls, catch basins, and trash racks.

Bridges are used to span streams or other terrain that cannot be traversed on the ground like a deep, rocky ravine; and they can add to the aesthetic beauty of a trail and the quality of the recreation experience. There is a wide array of materials available for bridge building, including steel, treated timber, log stringer, fiberglass, and other composites. Many are prefabricated, which aids in transport and assembly. Choice of materials can depend on local availability, local preference, or conformance with a local or agency architectural theme. Fiberglass, though not as aesthetically pleasing as other materials, is lightweight and easier to transport and assemble at the bridge site. Its initial cost can be higher than other materials, but transport and assembly costs are much lower.

Things to think about for bridges:

• There are specific criteria for bridge site locations and they are critical to the longevity and integrity of the structure. Seek help from a bridge specialist, engineer, or hydrologist.
• Most bridges will require a permit of some kind. Find out what is needed and what the requirements are for erosion control, etc. Get permitting started as early in the process as possible. It can take some time.
• Many streams have conditions or restrictions for operating equipment in or near the stream. Gather the information before mobilizing materials, equipment, and personnel.
• Time and unusual weather events can negatively affect a bridge’s integrity. Public safety trumps cost, so manage risk. Regular bridge inspections by a qualified engineer must be conducted and documented.
• Make the bridge large and durable enough for the largest vehicle using the bridge. In most cases this is construction or maintenance equipment, including snow groomers.
• In wet conditions, tires, especially OHV tires, can slide across the boards of a bridge. Ensure a rail or a rub rail is on the bridge to catch the tires before they go off the side.

Arches are used to allow water to flow under the trail. They are slightly elliptical and come in either an open or closed bottom configuration. Open bottom arches are most common in trail work. They have a flange on the bottom edge that allows them to be pinned in place with rebar. Arches are available in a variety of sizes and come in corrugated galvanized metal or corrugated high-density polyethylene (HDPE) plastic. Plastic is usually preferred due to its lighter weight and ease of transport and installation. Arches have a wide and low profile that gives them several advantages: a) the stream bed or drainage bed is left in its natural condition; b) the flow of water is less restricted, yet the capacity to carry water is one-third more than a similar sized culvert; c) the wider mouth of the arch is less likely to plug up with debris; d) the width of the arch makes it easier to clean out; and e) the arch shape is stronger than a round shape.

Culverts are another structure that allows water to run under the trail. The most common culverts are corrugated metal pipe, often referred to as CMP, and corrugated plastic pipe, commonly referred to as CPP. The metal pipe is aluminum or galvanized steel. The plastic pipe is HDPE. Metal pipe comes in a variety of shapes: round, elliptical, box, pipe arch, and arch. Round corrugated aluminum is the most common metal culvert for trails since it is 70 percent lighter than steel and just as strong. Plastic pipe comes in round and arch shapes. The round pipe is available with a single wall, which is corrugated inside; or a dual wall, which has a smooth interior.

There are two types of corrugations: annular and spiral. Annular is easier to band together, but each corrugation can become a sediment trap. Spiral tends to clean itself out better since one corrugation leads to the next. Plastic culverts are usually preferred for trails due to their light weight and ease of transport. They are also easier to cut in the field. Most culverts come in 20-foot lengths and have available bands to connect sections together as well as elbows, flared inlets, drop inlets, downspouts, and other attachments.

Plastic culverts are usually preferred for trails due to their light weight and ease of transport. They are also easier to cut in the field. Most culverts come in 20-foot lengths and have available bands to connect sections together as well as elbows, flared inlets, drop inlets, downspouts, and other attachments.

Here are some key points on culverts:

• Culverts need to be sized correctly to accommodate the maximum high flow events from the drainage area. Failure to do this can result in a catastrophic failure.
• Any pipe less than 18” in diameter is more prone to getting clogged with debris and harder to clean out. Ensure there is routine inspection and maintenance for these structures.
• Culverts can fail in a significant weather event causing the culvert and the trail to wash out. This may result in not only a severe trail impact, but also has the potential to impact sensitive habitats or fish-bearing streams below. For these reasons, fords or armored drains are usually a better alternative if management allows tire and water contact.
• Dual wall plastic pipe with the smooth interior tends to flush itself out during rain events or can be flushed out manually with a hose.
• Check the classification of the stream before installing a culvert. Some small streams, even ephemeral ones, are classified as fish-bearing and may require a bridge or other mitigations to allow fish passage.
• Cover depth will be lost through erosion, wheel displacement, and maintenance. To minimize the risk of having an exposed structure, culverts should have a minimum of 12” of fill over the top of them.
• Installing two smaller diameter culverts rather than one large one can increase the flow without increasing the height of the fill required to adequately cover the pipe.

A headwall is a structure that surrounds the inlet of a culvert or arch and has three functions: 1) to keep the trail fill from sloughing or eroding off and blocking the entrance of the culvert; 2) to help funnel the water into the culvert inlet; and 3) to dissipate the energy of the water and protect the toe of the trail fill from eroding. Headwalls are normally constructed of rock, but bags of premix concrete are also used.

A catch basin is often constructed as part of a culvert or arch installation, especially where the water needs to turn in order to enter the culvert. It usually consists of a headwall and an “L” shaped berm or wingwall either made of or lined with cobble rock. The water enters the catch basin, hits the back of the berm where its energy is dissipated, and then is allowed to turn and enter the culvert. Catch basins will fill up with debris and sediment and require routine inspection and maintenance.

A trash rack is installed in advance of the inlet of some culverts or arches to collect sticks, logs, and debris to prevent them from blocking the inlet. They are usually widely spaced metal screens or vertical metal bars. Sometimes, they are placed directly over the inlet, but this defeats the purpose as debris can plug up the culvert inlet. By preceding the inlet, the debris gets collected, but water can still flow through or around the debris to get to the culvert inlet. As with many structures, the key to their effectiveness is regular inspection and maintenance.

Elevating the tread above the water

Sometimes, it is desirable or necessary to cross broad wet areas. Boardwalks, corduroy, side ditches, puncheons, and turnpikes can all be used to elevate the tread above the water.

A boardwalk is essentially a trail on stilts that keeps the trail above the water level and out of sensitive riparian vegetation. Though expensive to construct, boardwalks allow access through sensitive environments, provide interpretive opportunities, are extremely aesthetic, and provide a unique riding opportunity that adds to the quality of the trail experience. Riders will remember the boardwalk and talk about it around the campfire.

Corduroy is an old technique of placing logs perpendicular to the wet area so that water runs through the voids of the logs and the vehicle tires run on top of the logs. This is generally not a long-term solution since the logs will eventually rot. There are two basic configurations for corduroy: logs placed on stringers and logs placed directly on the ground. Both can provide an uneven, slippery surface. When placed directly on the ground, some logs will sink or heave. In high water, they can float providing an unstable trailbed. Both methods can be rudimentary, but if properly installed and consistent with the management objective for the trail, they do work and will offer a unique riding experience and challenge that can add to the quality and excitement of the day’s outing.

A puncheon is basically a bridge that lies on the ground. It has stringers, deck, and rub rails that are laid on mud sills. It looks like boardwalk, but a boardwalk is on stilts which elevate it off the ground. Puncheons are typically used to cross wet, boggy, or seasonally wet areas. They can be used to bridge small creeks and protect sensitive resource areas like threatened or endangered plants or cultural sites. Materials are generally logs, sawed timber, treated timber, or a combination of those materials. Depending on how soft the ground is, the mud sills are placed directly on the ground or in shallow trenches that are dug down to firm ground, filled with rock or gravel, or filled with gravel on top of geotextile for increased bearing. The most common fault of puncheon installations is that they are too short and mud holes develop on each end. Be sure to terminate them on firm or higher ground. The approaches to structures like this are still subject to compaction and displacement, which creates low spots. To avoid this, the approaches should be hardened with rock or a geosynthetic with a rock cap. Puncheons can be slippery when wet, so grades need to be kept to less than 5 percent and approaches need to be on a tangent, not a curve. As with many other structures, puncheons enhance the riding experience while protecting resources.

Side ditches generally run parallel to the trail and help drain the trail tread by allowing ground water to seep into the ditch. The lower the groundwater level is, the drier the trail tread will be. When converting roads to trails, a good practice in wet areas is to use whatever excess width is available for a ditch. This helps drain the trail, enhance the trail experience by having a narrower trail width, and reduce the surface area of the trail. Like ditches along roads, side ditches need cross drains at regular intervals to reduce water volume and velocity and to help maintain the natural hydrology of the landscape.



Turnpikes have myriad variations, but the principle is always the same: use fill to raise the trail tread above the water table. The higher the tread is, the drier it will be. There are two configurations of turnpikes: ditched and ditchless. Ditched turnpike is most common and uses parallel side ditches to lower the water table. The excavation from those ditches is used as borrow to raise the elevation of the trail tread. However, there are times when sensitive resources prevent the excavation of a ditch or where the side ditches will interfere with the natural subsurface hydrologic flow of water by changing its direction. In these situations, a ditchless turnpike, called a causeway, can be used.



Most turnpike installations start with a layer of geotextile to separate the fill material from the underlying mud or poor quality native material and to increase the load-bearing capacity of the structure. Some installations encapsulate the fill with the geotextile, often called the sausage or burrito technique. Most turnpikes have logs, rocks, or treated timber to confine the fill to keep it from sloughing off into the ditches. The best surface, if available, is gravel or crushed rock with a shallow cap of soil to provide a durable tread surface and to help maintain the shape of the trail tread.

Ditched turnpike may require cross drains, culverts, and lead-off ditches to drain the side ditches. Over time, the ditches will slough in and collect debris, so regular inspection and maintenance is needed to retain the shape, depth, and function of the ditches.

Causeways can work well in seasonally wet areas with soils that drain well. They may not work well in perpetually wet areas with saturated soils since the structure may slowly sink into the ground. The use of a wider geotextile base or other geosynthetic materials may remedy this.

If a supply of mineral soil is available, a turnpike can be cheaper and easier to build than a puncheon, have less maintenance, and have a longer lifespan. Like many other structures, riding on a turnpike is different and adds to the rider experience.

Moving water across the trail

Water from springs, seeps, or ephemeral streams can saturate the trail tread and create mudholes. There are two ways to move the water across a trail: drains and fords.

Drains are structures that carry this water across the trail either on the surface or under the surface. Surface drains are a trench outsloped so the water runs across the trail and the trench is filled with cobble rock that provides weight bearing for the vehicles while allowing water to flow through the voids in the rock. These voids will eventually fill up with sediment and the water will then flow over the surface of the rocks. The most common subsurface drains are the French drain and curtain drain. The French drain is usually used to carry water under the trail from a point source of water like a seep or spring. It is a trench dug laterally across the trail, lined with geotextile, filled with clean drain rock, and then the geotextile is folded over the top. Usually, a perforated drain pipe is added as well to help carry the water. Unfortunately, the geotextile usually plugs up over time at the inlet causing the structure to fail. Also, if drains are not installed deep enough or if the cover material is not maintained, displacement will expose the geotextile and the integrity of the structure will begin to fail. For these reasons, a culvert or an armored surface drain may be a better alternative.

Curtain drains are installed longitudinally above the trail or along the inside shoulder of the trail. They intercept a sheet flow of subsurface water to prevent it from saturating trail tread or from pumping up through the trail tread with repeated traffic. Depending on the depth of the subsurface water layer, these trenches can be considerably deeper than those of a French drain. They’re usually lined with geotextile on the sides and bottom and filled with clean gravel or drain rock. They may or may not have perforated pipe in the bottom. Since they typically intercept a linear water source rather than a point water source, they can be 100 feet or more in length. For lengths greater than 50 feet, the water that is collected needs to be drained across the trail at regular intervals. The cross-drains can be surface drains at a grade reversal or rolling dip, or subsurface drains like culverts, or French drains.

Prefabricated geocomposite sheets or strip drains are also available that function just like curtain and French drains only they’re a whole lot easier to install, less expensive, and easier to replace if necessary. They are a piece of dimpled plastic encased in a geotextile fabric and they are available in rolls of various widths and lengths. The trench for these is much smaller and is backfilled with correspondingly smaller volume of sand rather than rock. Strip drains can be an alternative to the traditional trench drains that may be worth considering. Note: If too close to the surface, they can collapse under the weight of vehicles.

As with any structure, these drains need regular inspection and maintenance. French drains especially can clog with sediment and debris at their input point.

Fords are an on-grade, wet-tire crossing that can offer an alternative to the expense of a bridge or the risk of a culvert. They aren’t appropriate in some settings and their use is not allowed everywhere. The biggest issue with fords is the potential for sediment delivery from vehicle tires directly into the stream. From a rider standpoint, fords can offer fun, challenge, and a unique riding experience. There are advantages of fords over culverts: fords don’t have to be cleaned out, they can tolerate wide fluctuations in flow, and there is generally less risk of a major structure failure or washout.

Things to consider with fords:

• Fords work best on ephemeral or low-volume streams with low, stable water levels generally not exceeding 10” during the season of use.
• Check the classification of the stream before considering a ford. Fish-bearing streams or those with direct connectivity to community water intake will likely have restrictions or prohibitions on sources of sediment delivery. Some type of permit will likely be required.
• Check management plan direction, NEPA direction, agency policy, and state and local laws for restrictions and prohibitions before building a ford.
• As a general guideline, the farther upstream the crossing is, the more likely that a ford will be acceptable.
• For stability, the stream gradient must be very low or the ford will erode away.
• Trail approach grades should be low (4 to 10 percent) to minimize sediment delivery. Dropping off a steep bank into the creek creates a poor, non-sustainable approach.
• The stream bottom should be gravelly, not sandy or muddy. If it isn’t, then some type of hardening will be required.
• A stream bottom with small-sized cobble rock can work well. A crossing with larger sized rocks would need to be consistent with the difficulty level of the trail.

Redirecting water away from the trail

There are three ways to carry water away from the trail and redirect the flow of water to a more desirable location: lead-off ditches, sumps, and sediment basins.

Lead-off ditches are commonly used to drain grade reversals, rolling dips, and outsloped sections. If the material is suitable, push excavated material from the ditch onto the trail to be utilized as tread material, not away from the trail. As in all structures, regular inspection and maintenance is required to keep the structure functional.

On flat ground, it can be difficult to ditch the water away from the trail. One solution is to build a sump, which is essentially a hole in the ground that will collect any runoff water and allow any sediment to drop. A sump will eventually fill up with sediment and will need to be cleaned out in order for the sump to remain functional. The trail tread material that a sump captures can be re-used on the trail. Sumps can also be used to keep runoff water from flowing into an area where it shouldn’t go. When constructing a sump, it’s important to make it big enough to accommodate the expected runoff volume from an average storm. As in lead-off ditches and rolling dips, when digging a sump never waste the excavated material. Instead, use it as tread material or as material to build up the crest of the rolling dip. Sumps make a good source for borrow material.

Similar to sumps, sediment basins collect runoff water from the trail and allow it to drop its load of sediment before flowing out over the spillway. The difference between a sediment basin and a sump is that a sump generally has no outlet. Sediment basins are usually used in the vicinity of streams to reduce sedimentation and hinder the direct connectivity of water from the trail to the stream. The basin should be of sufficient size and depth to handle normal runoff. In general, a sediment basin has some form of hardening. The entrance can be lined with cobble rock to dissipate the water energy. The back and side edges are usually an earthen berm lined with cobble rock. Sometimes the berm is reinforced with geotextile under the rock. The outlet or spillway is slightly lower than the rest of the berm and it is usually rock lined as well. The bottoms of the basins can be lined with rock, but this can hinder the maintenance task of periodically removing the deposited sediment. Sediment basins will fill up with debris and sediment and require routine inspection and maintenance.

Using existing structures to control water

Structures that are used to cross major streams can be very expensive to build and maintain. A strategy that can reduce those costs and reduce potential environmental impacts is to utilize infrastructure that is already in place, such as road or other trail crossings. This may not be desirable from a purist trail perspective, but it is desirable from a practicality and management perspective. The infrastructure could be a simple ford, a large multi-plate culvert, or a bridge. In many cases, the existing infrastructure is already in the best crossing location and other options may be limited or not as suitable. If it is a road structure, access would require mixed use of the road but this could be for just the minimum distance required to cross the stream and get to a point where there is good trail egress with flat grades and adequate sight distance.

Several things need to be in place before utilizing existing structures:

• The trail needs to be directed to the existing infrastructure and this is not always possible.
• When using the structures of an existing trail, determine if the trail uses are compatible with the existing structure and if the structure will safely accommodate the OHV width and weight.
• Existing stakeholders need to be consulted to flush out any concerns and to build and maintain stakeholder cooperation.
• Appropriate signing will be necessary to warn everyone that the structure will be multiple-use.

The strategy of using existing infrastructure has been implemented very successfully on many projects. Short-term benefits include reduced environmental analysis, reduced engineering costs, and reduced project implementation costs. But the long-term benefits can reap bigger rewards in reduced maintenance and replacement costs. It may also foster cooperative efforts between motorized and non-motorized stakeholders.

Erosion Control Structures

Erosion control structures are commonly used and often required on construction sites to prevent storm water runoff from entering streams, riparian areas, or other sensitive areas. Their function is to reduce the velocity of the water and to trap sediment. They are also used to aid in closure; stabilization; rehabilitation of old trails; and any time the runoff is expected to be higher than normal and tax existing drainage facilities, such as after a wildfire, during or after a logging operation, or during an unusually wet rainy season. Erosion control structures are usually temporary structures since they do not have long-term effectiveness or durability.

The most common types of erosion structures are check dams; energy dissipaters; silt fences; straw or coir wattles; and straw, hay, or other bales.

Check dams are used to close or rehabilitate heavily eroded trails or to stabilize the continuing erosion and growth of ravines. The word “dam” is a slight misnomer since most check dams allow water to percolate through them. The principle of the check dam is to reduce the velocity of the water so it will drop its load of sediment behind the dam. Eventually, the dam will fill up with sediment, which will help stabilize the floor and sides of the ravine or trench. The dams should be installed at regular intervals down the full length of the ravine or trench. Though check dams can be difficult to install, they are highly effective. Materials are usually cobble rock, logs, and treated timber, though steel guardrail has also been used. While curbing erosion from above, the dams also act as barriers to deter riding from below.

An energy dissipater is any structure that slows, redirects, or interferes with the flow of water. Water velocity is what erodes the soil, so the amount of sediment being carried by the water is directly proportional to the velocity of the water. The most common dissipater material is cobble-size rock or larger, but logs, steel, woody debris, or other materials can be used as well.

A dissipater should be considered at the outlet of any corrugated culvert installed on a grade exceeding 10 percent and on any smooth-walled culvert exceeding 5 percent. An energy dissipater should be considered at trail drainage points that have the potential to drain a high volume of water, especially if that drainage point is on a fill or a steep slope. Armoring the slope with rock reduces the velocity of the water and protects the slope from erosion.

Silt fence is a water-permeable geotextile fabric held upright and anchored to the ground by regularly spaced stakes. The fabric allows water to slowly seep through it, but it filters out the sediment carried by the water. One advantage to using a silt fence is that it is readily available at most large home supply stores or farm and ranch stores. It can quickly become unsightly and should be removed after it is no longer needed.

Straw or coir wattles are commonly seen in the ditch lines along most road construction projects. They are net bags filled with straw or coconut fibers so they look like small logs. They come in a variety of diameters and lengths and are usually staked in a herringbone pattern at regular intervals in a drainage way. When used in trail or slope rehabilitation, they are placed on the contour at regular intervals down the slope. The steeper the slope, the shorter the interval. Wattles break the slope into smaller watersheds, which reduce water volume and velocity. The wattles trap sediment, but allow water to filter through slowly.

Bales have the advantages of availability, easy installation, and portability. Bales placed at regular intervals down a slope prevent water from gaining too much volume and velocity. This protects the seeding, mulching, and other erosion control efforts. In addition to straw bales, cedar shaving bales are also available. Cedar bales are heavier than straw, but they last longer and do not need to be certified as weed-free. Bales can also be used as a visual and physical barrier.

Section 2: Terrestrial Control Structures

Retaining Structures

There are two types of retaining structures: gabions and retaining walls.

A gabion is a rectangular wire basket that is filled with rock. Once filled, a wire lid is secured in place. Gabions are support structures that are commonly used for bridge abutments, retaining walls, and stream bank protection. The top of the gabion should not be used for the trail tread since the wire mesh will eventually break and puncture tires.

Retaining walls hold material in place and include bin walls and crib walls. Bin walls are closed wall structures that are back filled to create a gravity fed retaining wall. Crib walls are created by stacking members (timber, steel, etc.) which creates a void that can be filled by rock or soil. Materials typically used for retaining walls include log, stone, treated timber, geocell, encapsulated geotextile (grass pavers which can be filled with dirt and stone to create a wall), interlocking concrete blocks, and steel guardrail sections. Often, the inside of the structure is lined with geotextile, which increases strength and helps contain fill material. Retaining wall kits are also available that provide durability, portability, and ease of assembly.

Common uses for retaining walls include the following:

• To support the trail fill when side slopes are too steep, too unstable, or when full-bench construction is not desirable or feasible.
• To contain or stabilize the cut bank in steep ground, unstable soils, or loose rock like scree.
• To minimize the footprint (size of cut slope and fill slope) of the trail to enhance aesthetics or to protect resources.
• To contain trail fill material on bridge approaches and abutments so soil doesn’t leach into streams, riparian areas, or other sensitive resources.

Structures for Controlling and Directing Access and Use

Managing entrances and using tank traps, barriers, fences, gates, and cattle guards all help control and direct the riders’ direction.

Entrance management is accomplished with a structure or a combination of structures and signing to inform the rider of the type of vehicle or vehicle width allowed on the trail. Bollards, barriers, or sections of fencing are often used to restrict vehicles exceeding a certain width from entering the trail. Entrance management is also a technique used to inform riders of the actual difficulty they will be encountering on the trail. Too often, a more difficult or most difficult trail does not appear challenging at the entrance to the trail, so riders start riding the easier part of the trail and then encounter a section with a technical challenge that may be beyond their riding capabilities. With entrance management, technical features (often called filters or qualifiers) consistent with the difficulty level are placed across the entrance of more or most difficult trails so riders immediately know the level of skill needed or the requirements of the vehicle for the trail to be successfully negotiated. This protects the riders, but also protects the trail from undue impacts. For risk management and for rider safety and enjoyment, this technique should be used at the entrance of any trail that does not appear to be as difficult as it is signed.

Effective entrance management controls use and sets expectations by answering questions for the rider:

• Which trail is it? This is indicated by a trail marker that shows at a minimum a direction arrow and the trail number (or name).
• What is the difficulty level? This is shown on the trail marker and indicated on the ground by a filter when necessary.
• Who can use it (use types)? This is shown on the travel management sign and sometimes shown on the trail marker. Width-limiting devices or barriers can be used to prevent some types of uses from accessing the trail.
• When is it open or closed? If necessary, this can be shown on the travel management sign or other regulatory sign and is often indicated on the ground by a gate or barrier across the trail entrance.

Other information that is often provided at a trail entrance is a "Two-Way Trail" warning sign or "One-Way" or "Exit Only" regulatory signs when appropriate.

A tank trap is a structure commonly used as entrance management to close or restrict motorized access to roads or trails. It is constructed by digging a hole and using the excavated material to build up a berm in front of the hole. Often called “Kelly humps,” the combination of the hole and berm can create a formidable structure that can be 12 to 15 feet deep. There has been much debate on the use of tank traps. On the one hand, they do provide a visual barrier to indicate that the road or trail is closed. On the other hand, for OHV riders looking for challenge, a tank trap can look inviting and attract unwanted use. Just a mound of dirt does not effectively communicate a closure. Unintentional use on poorly located or poorly signed tank traps can result in severe injuries or death. Tank traps can be especially hazardous if the road or trail is closed in the summer to motorized use, but open in the winter to over-snow use. In poor light or blinding snow, a snowmobiler can unknowingly ride into a tank trap.

Barriers are another management tool used to control and direct where the riders can or can’t go. Riders’ eyes are constantly scanning for the open route and the best line through that route. It does not take much of a barrier to catch the riders’ eyes and deter use. As such, a low, unobtrusive barrier can be just as effective as a large visually obtrusive barrier. A variety of materials can be used for barriers, including dirt, vegetation, logs, wooden rails or poles, rocks, steel, tires, hay bales, or treated timber. The choice of materials usually depends on local availability, price, architectural theme, or factors such as the risk of vandalism. The material selected can either send a strong visual message or a subtle one. Once a material is selected, it should be used throughout the project so that a consistent message is sent to the riders.



When used for closure or rehabilitation, the most effective installations include a sign behind the barrier saying “Area Closed” or “Trail Closed.”

Like barriers, fences are used to control and direct the trail use. Materials used to construct fences are often metal, chain link, barbed wire, plain wire, treated timber, rail, split-rail, and log. Material selection is often dictated by local supply, price, or architectural theme. Once a material is selected, it should be used throughout the project so that a consistent message is sent to the riders. As with barriers, fences can add to (or distract from) the aesthetics of an area. They can provide a subtle guide or a strong constraint. Fence lines should also be shown on the trail map to aid in orientation and rider awareness.

One issue that often occurs is a trail paralleling a barbed wire fence. Many factors need to be considered when siting a trail parallel to this type of fence, including speed, traffic volume, tread width, and smoothness of the tread surface. Consider also the consequences of a rider losing control. If the tread is narrower and the surface is loose rock, the risk goes up and that should be reflected in the difficulty level assigned to the trail.

Gates can be a good management tool, but their primary use is to control access and facilitate travel management. Gates are commonly used for seasonal closures, such as deer winter range or snow melt; to protect resources in cases such as after a natural disaster or other storm events; or as part of entrance management.

There has been much discussion about the effectiveness of gates. They can foster ill will because those with a key can go in, but others are restricted, so they are prone to vandalism. Gate effectiveness uses three of the 4Es. A gate is an engineering structure, but it needs to be supported by education and maybe some enforcement. Most people will respect a closure if they understand the reason behind it. Put up a sign explaining the closure and back that up with information on the trailhead kiosk, the map, website, and other media. Time and effort spent on education will be rewarded with compliance, user satisfaction, and reduced risk of vandalism.

Chains and braided cables are sometimes used as an inexpensive alternative to a gate. DO NOT DO THIS. Gates are visible structures and most have signs or reflective markers on them to increase their visibility, but cables and chains hang low, are usually very thin, often poorly marked, and can be extremely hard to see in a storm or low light. They can be death traps, especially if the trail is also used in the winter by over-snow vehicles. Manage risk. Install the proper structures that will increase public safety and reduce liability.

Things to think about with gates:

• If possible, locate gates where vegetation or topography will inhibit bypassing.
• Use signing and education to inform riders as to why a gate is closed.
• Gates that are sometimes open or sometimes closed to manage access should have red and white retroreflective tape or object markers to increase their visibility. This is a simple step to help manage risk, and this protocol should be included in the project sign plan.
• Gates that are locked in the closed position should also be locked in the open position so that only management has control of the access.
• When gates are used for resource protection, ensure that they are opened in a timely manner when that protection is no longer needed. Similarly, when used for a seasonal closure, ensure they are opened on the date they should be opened.
• Gates should be fully closed or fully open and never in a partially open position. A partially open gate can be a serious safety hazard when there is limited visibility. Manage risk. Ensure that all gates have positive, functional latches or closure mechanisms.
• Work with human nature, not against it. If the complaint is that riders are leaving a range gate open, don’t have a crude barbed wire gate closure that can shred expensive riding gloves and jerseys or is difficult to open and close. Use the 4Es. Improving engineering by installing a cam-lock gate closure device will increase compliance and facilitate OHV management.
• Never direct traffic around a locked gate without designating the side route as open, otherwise the public learns to ignore a locked gate.

Cattle guards are often installed for livestock management. There are two basic configurations: arched and on-grade. Arches can be a good choice in rocky terrain or where resources preclude excavation. Having a dogleg in the trail alignment on each side of the cattle guard will control the speed of approach. The dogleg allows adequate sight distance but not enough distance to gain speed. On-grade structures can be easier to traverse, but they may require more frequent clean-out. A steel deck is far more durable than treated timber and a much better option.

All cattle guard installations should have a bypass gate to allow passage of equestrians, stock, pedestrians, or maintenance equipment. They can be very slippery when wet or icy. For rider safety and risk management, cattle guards should be installed on tangents, never on a curve, on the flattest grade possible, and level from side to side. Angled wings provide a margin of safety and allow room for transporting over-width materials or game.

Cattle guards are commercially available, but many agencies make their own. There is more science in design and rail spacing than one might think. Improper design such as too deep or too shallow trenches, sharp edges, slippery materials, too great an angle, etc., can pose a risk to both the cattle and the riders. Use caution when attempting to design a cattle guard.

Heavy Equipment

Here are some thoughts regarding heavy equipment:

• There isn’t one do-all machine; it usually takes a combination of equipment to accomplish all of the necessary tasks.
• Program managers should identify equipment needed for the short term (construction) and equipment needed for the long term (operation and maintenance).
• Managers should examine options to borrow, rent, or contract the equipment for the short term.
• Program managers should only buy the equipment they know they will need, not what they think they might need.
• In most cases, managers should not buy equipment that is wider than the intended trail widths.
• Equipment is just a tool that is useless and potentially detrimental without a skilled operator who has the finesse, vision, and experience to create a great trail and maintain it as a great trail.
• Trail construction takes a different skill set than road construction, so there can be challenges in trying to train a road builder to be a trail builder.
• Trails are a narrow path on steep, rocky, irregular, and often soft ground. Any machine can quickly go sideways and the operator must instantly know what to do. All operators must be trained. Don’t trade expensive, but experienced operators for inexpensive, but inexperienced operators to try to save money. It could be a costly decision.
• As a minimum, managers should ensure that other personnel are on site in the vicinity of equipment operation. On technical terrain, spotters should be working with each piece of equipment.

There are five main performance categories for heavy equipment: loaders, haulers, pushers, diggers, and other. Some equipment like dozers are purpose-built to perform as pushers, while others, like excavators and skid steers, have the ability to perform well as loaders, haulers, and diggers.

Dozers come in all shapes and sizes, but trail work usually requires only two sizes of dozer. Trail dozers have a track width of less than 50” and full-sized dozers are everything over 50” wide. Mechanized trail building is 10 times faster and cheaper than building by hand, and trail dozers are purpose-built for trail building. Though small in size, they are powerful and versatile with a six-way blade and draw bar with rippers. A variety of attachments are available, and they can grub a stump or move a large boulder. One advantage they have is that they can maneuver easily within the tighter confines of a trail corridor and minimize environmental impacts. The full sized dozers are great for anything which requires a larger foot print than can be accomplished by the trail dozer.

Excavators are diggers and loaders. They are extremely versatile pieces of equipment because they can construct tread, dig holes, dig ditches, pluck rocks or stumps out of the ground, and drag debris in or scatter debris out of the trail corridor. Most have a two-way blade, but some even have six-way blades for efficient grading and shaping. Having a thumb on the bucket increases the machine’s versatility.

With a large selection of excavators in the rental market, it is easy to match the best sized machine to the job; two to look for are mini-excavators and full-sized excavators. It’s hard to beat the versatility and finesse of a mini-excavator, which is less than 50” in track width. Many have adjustable-width tracks, a zero clearance cab, and a bucket with a thumb for handy plucking and placing.

Full-sized excavators are handy for constructing wider trails, closure and rehab, road-to-trail conversion, and facility construction. Often, the ideal equipment combination is a trail dozer and a mini-excavator working together.

Small size, fast walking speed, and a host of attachments give skid steers great versatility and make them ideal companions with other equipment to accomplish a wide range of tasks. They can be pushers, diggers, loaders, and haulers. One advantage is that they are readily available at most rental stores. Mini-skid steers are commonly called walk behinds because there is no operator cab or seat post. These small machines are maneuverable and have many of the same attachments as their big brothers. The common name is a misnomer since most have a platform for the operator to stand on. They don’t have the force of a trail dozer, but they can work well for light excavation on flatter ground or finish work. Many have a six-way blade that helps them cut into shallow sidehills with soft soils. The auger attachment is handy for sign or barrier posts, but a slow walking speed does not make them efficient for widely scattered installations.

A tractor with a backhoe attachment can be very handy to load and haul material and to dig holes for barriers, fence posts, and sign posts. Thus they fall into the loader, hauler, and digger categories. Four wheel drive is recommended for most trail applications. Their fast walking speed gives them an advantage over mini-excavators or dozers with backhoe attachments when work is scattered over a wide area. Their three-point hitch and power take-off (PTO) allow for a wide range of power attachments from box blades to mowers.

Trail dozers, mini-excavators and mini-skid steers are commonly used to build single-track trails. Motorcycle riders have always coveted sweet single tracks, but when it comes to a designed trail, the issues have always been how to build it and then maintain it. Riders will volunteer to build the trail and do. But it is a slow, laborious process and few volunteers can or will return day after day. Purists will say that the only good single track is hand-built single track because it is more natural. When done properly, it is pretty hard to tell a hand-built trail from a machine-built trail. It all comes down to the skill, vision, and conscientiousness of the operator. After some time, compaction and displacement will cause roots and rocks to show on the surface; the sides will revegetate; trees will have fallen and been bucked out to a narrow width; and forest litter will make it look like it’s been there forever. What is the big difference? With equipment, the production rate is much higher and the cost of construction is much lower. There are now machines that have been purpose-built for single-track trail construction and maintenance.

The current single-track-specific machines are the single-track ST240 and the Sutter 300. The single-track ST240 combines the versatility of an excavator with the power of a dozer. It has a bucket, thumb, six-way blade, 24 to 36” adjustable-width steel tracks, 32 hp turbo charged diesel engine, optional winch, and a choice of ride-on or remote control operation. The Sutter 300 mini-trail dozer has a six-way blade with lift and tilt float, 29.5” wide steel tracks, auxiliary hydraulics, 44 hp turbo-charged diesel engine, operator post seat, and an optional winch.

Though not heavy equipment, the Rokon is a two-wheel drive fat-tire motorcycle series. It is a powerful and versatile machine to haul tools, materials, or personnel into a single-track work site. Sometimes, agencies do not monitor or maintain the single track that they have or avoid new single track because they don’t have personnel who are comfortable riding motorcycles. Low, stable, and easy to ride, this machine helps address that issue.

Rock crushers fit into the “other” category. And there is usually a need for crushed rock on most trail projects. If a trail has sections of loose cobble rock, scree, lava, river rock, or glacial till and if those sections are not consistent with the intended difficulty level of the trail, crushing that rock in place can provide a more ridable and stable trail tread. Rock crusher attachments are available for skid steers, excavators, and some trail dozers. Grinders and pulverizers are available for loaders and other equipment. If there is a source of suitable rock, a portable crusher can be brought in and set up on site. The crushed rock is then loaded into dumpers and hauled to the work site.

Rock, aggregate, and good quality soil are a great resource for check dams, bridge abutments, drains, headwalls, energy dissipaters, or trail hardening. The issue is getting the material from the source to the site. One solution is a motorized toter or dumper. They come in all shapes and sizes and some are even self-loading. Because they need to fit on the trail and traverse rough terrain, they can have a slow walking speed and relatively low carrying capacity. If there is a lot of material to be moved for any distance, several dumpers may be needed.

Drags are pull-behind grooming tools that are used in both construction and maintenance. The best drag or combinations of drags is often found by trial and error on a specific site. The choice of implement depends on many factors such as the task at hand, soil type, trail width and alignment, use type, and required maintenance frequency. There are five main types: flexible drags, rigid drags, rock rakes, box blades, and other.

Flexible drags are pasture drags or tine harrows that are made from a draw bar and flexible steel web with steel tines on one side of the web. They can be flipped over when traversing rocky trail sections so the tines don’t unearth more rocks. With the tines down, they smooth the trail tread, remove small rocks, and collect woody debris. As the debris collects under the drag, the operator must sporadically stop, flip the drag over, and clean it out. They are great for dressing up a newly constructed or reconstructed trail. Flexible drags are effective in loose soils, but not effective in compacted soils since they have limited weight and cutting ability. Being flexible, they are also not effective in smoothing out a heavily moguled trail since material is removed from both the humps and the dips.

Flexible drags can be modified in many ways, including replacing the round draw bar with a piece of channel iron or square tubing for more weight and cutting action. A piece of channel iron can also be added to the rear for more rigidity, weight, and cutting and smoothing action.

A downside of flexible drags is that they are always on the ground. They work well for construction since everything needs to be groomed, but not for maintenance where one section of trail may need grooming, but not the next section.

Rigid drags, the second type of drag, are long, rigid, and usually have cutting blades in a variety of configurations similar to a snowmobile trail groomer. Some rigid drags have cutting blades with adjustable angles and heights and most have rear wheels that can raise the whole implement off the ground for easy transport. Rigid drags will work in compacted soils to cut and fill moguls and to smooth out the trail tread. They are heavy and if they are allowed to cut too much, the weight can tax the transmission of the tow vehicle. Being long and low, they are not very maneuverable and they usually don’t work well in super tight trails. In open country they can be quite effective.

Rock rakes, the third type of drag, have a steel bar with spring steel curved tines bolted to them. Their name is misleading since the equipment is a rake, but not necessarily intended to only rake rocks off the trail. They have either electric motors or electric and hydraulic motors so that both the height and the angle of the comb are adjustable. Most have a u-joint coupler, a handlebar-mounted control box, and a safety breakaway wiring harness. The tines will wear out but they are replaceable. These are the most effective grooming tools on the market and will work in soft soils, compacted soils, and moguls. The small tines have a large psi so they have a powerful cutting action. The adjustable comb allows the operator to direct where the material goes.

With the comb off the ground, these are easy to back up, turn around, or avoid sections that don’t need grooming like rock gardens.

Most vendors make two models of rock rakes. One has a fixed comb where the comb rotates on a fixed axis. The other has a sliding comb that not only rotates, but extends out from one side to the other. The advantage of the sliding comb model is that it can retrieve berms that have built up along the sides of the trail. Their downsides are that they are heavier, have a higher center of gravity that may not work well on superelevated curves, and are considerably more expensive. A fixed comb model can also retrieve berms if there is enough clearing width to allow the tow vehicle and the groomer to straddle the berm. For most routine maintenance, the fixed comb groomer is both effective and a better value.

Box blades, the fourth type of drag, attach to the three-point hitch of a tractor and are very common in track and arena grooming. Most have a set of ripper teeth mounted inside the box and the teeth can be down or up. The box shapes and compacts the ripped-up material. They are available in a variety of widths down to 4 feet and can work in a variety of soils. Unless the tractor is equipped with a float mechanism, a box blade will not work well on undulating or moguled trails. Other potential pitfalls are that they tend to cut a trench; the operator cannot drift material from one side of the trail to the other; and it is difficult to reach out and bring in berms.

The last type of drag is for everything else from bed springs to discs to tires. There are a lot of implements commercially available, or the trail team members can get creative and fabricate their own. They shouldn’t be afraid to experiment until they find the implement or combination of implements that work the best for their situation.

Compaction equipment compresses soil or rock particles into a denser mass that increases durability and bearing strength. It is essential for the stability of large embankments. It’s an important element in the installation of structures such as for the packing material behind retaining walls, bedding culverts, and foundations for bridge abutments. The desired density is best achieved when material is placed and compacted in shallow layers. A compacted trail surface, whether native surface or crushed rock, will retain its shape far longer than a non-compacted tread because it resists the forces of displacement.

A huge assortment of compaction equipment is available, including tampers, plates, and rollers that are either hand operated, self-propelled, or attached to other equipment. Vibratory rollers will compact better and deeper than non-vibratory rollers. Even without specialized equipment, some degree of compaction will occur just by running whatever equipment and vehicles are on site over the full width of the trail.

A wide range of trailers are useful to haul equipment, materials, and supplies. There is not one do-all trailer and most O&M programs have a fleet of highway trailers and off-highway trailers. Highway trailers are usually full-sized flatbed trailers designed to haul equipment or utility trailers designed to haul materials. Off-highway trailers can help bring materials, equipment, and supplies to a trail work site. They can be pulled by ATVs, ROVs, or skid steers. The trail team members should heed towing capabilities of the tow vehicle before loading up a trailer. Uneven terrain and steep grades add to the challenge of towing off highway so exceeding the tolerances can be risky.

Equipment Drive Characteristics.

Steel Tracks:	Rubber Tracks:	Tires:
Durable	Durable on dirt, but a lot of sharp rocks will eat them up	Durable
Low PSI due to high ground contact area	Low PSI due to high ground contact area	Higher PSI due to lower ground contact area
Excellent traction in dirt and mud	Good traction in dirt and mud	Poor traction in dirt and mud
Poor traction on rocks	Better traction on rocks	Poor traction on rocks
Will not slip off in uneven terrain, but they can bind up when clogged with debris	Can slip off in uneven terrain	Potential to break the bead or puncture sidewalls in uneven terrain
Higher potential ground impact	Lower potential ground impact	Higher potential ground impact
Better on steeper grades	Good on steeper grades	Poor on steeper grades, better suited on flat grades
Smooth ride	Smoother ride	Bouncy ride
Highest potential to break or dislodge roots and rocks	Lower potential to break or dislodge roots and rocks	Lower potential to break or dislodge roots and rocks
Steel grousers can damage bridge decks and other structures	Much less potential for structure damage	Much less potential for structure damage

Equipment Comparison: Dozers vs. Excavators.

	Dozers:	Excavators:
Functions	Push, sidecast, rip, back blade; good for construction and maintenance	Dig, pluck, place, load, scatter; limited push and back-blade; good for construction, finish work, local maintenance.
Material Handling	Push, sidecast	Pluck and strategically place
Brushing	Unable to remove debris from embankment area on steeper ground	Able to remove debris from embankment on any slope
Cut slopes	Unable to shape steeper cutslopes	Able to shape any cutslope
Maneuverability	Needs flatter area to turn around. Locking tracks increase ground disturbance	Only needs enough clearance to swing cab to change direction
Stability	Low center of gravity helps stability but stability affected by rocky or slippery slopes	Higher center of gravity can hinder stability but ability to use boom to stabilize on rocky or slippery slopes
Compaction	Excellent embankment compaction by track-splitting or optional mechanical roller	Can use boom to compact embankments or use optional mechanical roller
Slash and Debris	Clears debris deposited in mound or ball	Able to scatter debris on any slope
Objects	Can roll objects but creates ground impacts outside trail prism	Can reach, grab, place objects while staying in trail prism
Digging	Good for trenches and large holes	Good for ditches, post, barriers

Hand and Mechanized Tools

No trail can be constructed by heavy equipment alone. Hand tools do the clearing, pruning, root cutting, structure assembly, and the final finesse work to make it all look pretty. Three common mistakes that are made when purchasing tools are: 1) not buying a good variety of tools like shovels, Pulaskis, and McLeods; 2) not buying enough of each tool; and 3) not buying or renting the right specialty tools (like drills, augers, and rock hammers) that make tough tasks easier. Each tool has a purpose and not having the right mix of tools can make a task much more difficult. Building a single-track trail with just shovels is a waste of time and energy. Tools have a tough life and often a short life as they get misplaced, broken, dulled, and misused.

The following paragraphs describe some of the most common hand tools for trails.

Pulaskis are one of the most essential trail tools because they can cut, chop, dig, and pry.

McLeods are the second most essential trail tools. They combine a hoe and a rake and are great for chopping, moving dirt around, raking out rocks, and shaping the tread, rolling dips, or lead-off ditches.

Chainsaws, with a variety of chain and bar configurations, are essential for cutting trees, logs, brush, and trimming posts, barriers, and other wooden structures.

Loppers are great for pruning small limbs and cutting roots out of the cut bank or trail tread.

A good quality folding saw makes cleaner and closer cuts than a chainsaw and is very handy for final touch-up pruning. Adjustable pole pruners are great for trimming long droopy limbs and they’re much safer and faster than using a ladder or standing on top of a vehicle.

Gas-powered brush cutters and hedge trimmers are great for removing or cutting back underbrush, both in construction and maintenance. Hedge trimmers come in either standard or pole units. They are good for keeping new growth from side vegetation from creeping into the trail in places where the tread is already established. Brush cutters come with a variety of implements from blades to nylon string. Choose the correct implement for the largest growth which needs to be cut.

In a deciduous forest, leaves can be a nuisance. Leaf blowers can remove leaves from the work site or blow leaves back onto cut or fill slopes to provide a natural appearance and to protect them from exposure to the elements. Blowers are also handy for removing dirt from bridge decks and other structures.

Spade shovels are indispensable for digging holes, moving dirt, prying out rocks, and cutting roots.

Bow rakes or smaller landscape rakes smooth out the surface and remove small rocks and woody debris. They are great for final shaping and finish work.

It is always amazing how many rocks there are in the exact place a hole needs to be made. Rock bars and tamping bars help to break up or dislodge rocks. A tamping bar is pointed on one end and has a small flat plate on the other, so it can be used for digging and compacting.

Depending on soil type and time of year, post hole diggers and power augers can be great for digging holes for sign posts and barriers.

Portable air compressors are essential because there is always a need for compressed air. Tires go flat, filters need to be cleaned, dirt needs to be blown off parts or personnel, air tools can be more powerful than hand tools, and the list goes on. An industrial-grade air compressor is an essential component in the shop, shop truck, or field staging area. Some heavier equipment offers a compressor as an accessory and this is usually a worthwhile option to consider. Having the ability to use pneumatic drills, rock splitters, and compactors can save a lot of manual labor and is more efficient.

Portable generators are another essential tool because there is always a need to power lights, tools, battery charging stations, etc.

Sometimes, just the tip of a rock needs to be moved out of the way, not the whole rock. And sometimes it seems that rocks are anchored to the other side of the world. In those situations, having a pneumatic, gas, or electric rock hammer or drill is both safer and faster than ordinary hand tools.

Many of the wooden structures require the drilling of holes for bolts or drift pins. This can be a tough task that requires electric- or gasoline-powered drills and long drill bits.

Equipment and tools break. Being able to weld on site with a portable welder can save on downtime and expensive trips to a repair shop.

Equipment will also get stuck or find its way into a precarious position. Having a winch suddenly becomes an essential item in these situations. When ordering equipment, it is usually wise to purchase a winch if it’s an available option. Chainsaw winches, come-alongs, and OHV winches can be invaluable in moving rocks or logs and in placing bridge stringers, puncheon, and other structures.

The list can go on forever, but some other tools worth mentioning include the following:

• pick mattock
• hazel hoe or adze
• mallet
• sledge hammer
• hand seeder
• fence stretcher
• fiberglass marker installer and removal tools
• T-post driver
• pop rivet tools
• complete mechanics tool sets (both standard and metric)
• cordless drill with bits, drivers, and spare battery
• hand saws
• corded or cordless circular saws
• A tool bag is great for everything else:
  • sockets and wrenches for whatever size hardware is being used on the project
  • an assortment of hardware
  • an assortment of decals
  • a fencing tool
  • torpedo level to make sure the signs and posts are straight
  • 25’ tape measure
  • notebook and pencil
  • hammer
  • scrench saw tool
  • ear plugs
  • 4-way screwdriver
  • pliers

Signing

Signing gives the rider key information about the site, rules, orientation, education, and safety. By clearly conveying these messages, management can better control and direct the use, maximize rider safety, and minimize agency risk. But signing does more than just convey a message, it conveys an image and an expectation: this site is professionally managed. Visitors will respond to that image with increased respect and compliance.

Here are some key points on signing:

• Have a sign plan. This ensures consistency with sizes, shapes, colors, messages, placement, and decal application protocols.
• Signing must be clear, concise, and effective. Follow the Keep It Simple (KIS) principle.
• Trails are like miniature roads and should be signed in the same manner as roads.
• Ensure that signing on the ground agrees with the information on the map or other handouts and media (website, downloadable maps, downloadable GPS data, etc.).
• When first entering a trailhead, signing will give visitors their first impression of the site, its management, and its maintenance. Make it a good and lasting impression.
• Provide the information that is essential for the rider to know.
• During project development, the importance of signing is often overlooked and its cost is often underestimated. Signing costs can be significant and need to be factored into the project budget to ensure quality signs and signing.

A sign plan can be very detailed and provide site-specific data on sign location, sign type, and message. Or it can be a programmatic sign plan which identifies typical signing scenarios for a project area and provides guidance on what signs would be appropriate in each of those scenarios. This provides consistency by ensuring that similar scenarios have similar signing. In each scenario, the plan discusses the signs that are needed and their function. It provides guidance on the sign shapes, sizes, colors, messages, letter sizes, reflectivity, materials, decal placement protocols, and sign installation protocols.

Other benefits of a sign plan include:

• Identifies a sign theme that is consistent with the architectural theme and landscape setting for the project site.
• Helps ensure that the proper sign types are used in a given scenario.
• Minimizes sign clutter and maximizes sign efficiency.
• Provides all personnel with the same vision.
• Allows managers to budget for sign needs according to the vision.
• Allows volunteers to install and maintain the signs according to the vision.
• Over time, management and personnel will change, and a sign plan will maintain continuity and consistency through these changes.

There are eight key elements in effective signing (need, simplicity, clarity, quality, consistency, placement, monitoring, and maintenance) and having a plan helps address all of them.

1. Need

• Determine the reason for a sign or if a sign is necessary.
• Are there other options instead of signs? Can the hazard be eliminated or mitigated? Can the trail be realigned or relocated to eliminate the hazard? It’s easier to put up a sign than to physically correct the problem, but this may not be the best long-term solution.
• If a sign is needed, choose the appropriate sign from the sign.

2. Simplicity

• Keep it simple and avoid clutter.
• The public spends very little time reading signs, so make them count.
• Use enough signs, but avoid over-signing.

3. Clarity

• Use clear, concise messages.
• Will the rider understand the intent of the sign?
• Whenever possible, use symbols rather than words.

4. Quality

• Use durable materials that are vandal-resistant.
• Make sure the sign is taped to protect it from UV light or snow shear.
• Use professional letters and templates.
• Make the sign messages appropriate and professional.
• Check, re-check, then check again for correct spelling.
• The sign and the installation should be neat, legible, straight, and professional looking.
• The public respects quality, but quality does not necessarily equate to expensive.

5. Consistency

• Do all of the signs meet shape, color, reflectivity, and message standards?
• Are similar hazards and situations signed identically?
• Is the signing consistent with that of other OHV trail systems in your area, state, or province?

6. Placement

This is perhaps the most critical and abused element. Most OHV trail signs are viewed from a moving vehicle, so signs need to be sized and placed where they are readily visible.

Install signs where the riders would expect to see them (generally on the right-hand shoulder of the trail, not up in a tree). This is where drivers and riders have been programmed to look for them. Occasionally, due to alignment or vegetation, a sign may be more visible if placed on the left side of the road or trail. Riders’ eyes constantly scan the trail to pick the best line, but they aren’t scanning trees and bushes looking for signs, so place the signs where the riders’ scan will pick them up.

• Avoid placing signs in shadows or where vegetation may obscure them.
• Place the sign enough in advance of the hazard to allow sufficient time for the rider to see it, read it, comprehend it, and react to it. This is called the Perceive, Identify, Emotion, Volition (PIEV) time. The minimum sight distance for a warning sign should be 175 feet.
• The intent is to have professional looking signs, so all signs and posts should be as level or perpendicular as possible.
• When signing, assume that the rider is a beginner, unfamiliar with the trail, and there is poor light and visibility.

7. Monitoring

• Monitor the condition of the signs and supports on a regular basis.
• Check color, reflectivity, placement, and overall effectiveness of the sign.
• Review the signing under a variety of light and weather conditions.
• Use an outsider or someone unfamiliar with your trails and signs to objectively judge the effectiveness of the signing.
• Don’t be afraid to take down signs. More signs are needed early in a new program to educate the public, but may not be needed in three to five years.
• An annual evaluation is suggested. Evaluate the following:
  • Are signs visible?
  • Are signs missing?
  • Are the existing signs in good condition
  • Are the signs in compliance with the current standards?
  • Are any signs no longer necessary or appropriate?
  • Are messages appropriate or accurate?
  • Are new signs compatible with existing installations?
  • Based on accident reports or near misses, are engineering studies required to determine additional signage to alleviate a safety concern?
  • Have signs been evaluated at night to determine their overall effectiveness and retroreflectivity?

8. Maintenance

• Repair or replace signs as needed to maintain quality appearance and function.
• Keep vegetation pruned back so the signs are visible.
• Bullet holes invite more bullet holes.
• Warning and regulatory signs must be in-place and legible.

Types of Signs

When signing, it is important to use the right type of sign in the right situation.

Sign Colors

As per the Manual on Uniform Traffic Control Devices (MUTCD) and EM7100-15, signs should conform to the following standard colors.

Red is used only as a background color for Stop signs, Do Not Enter, and Wrong Way signs. Red is used as a legend color for Yield signs, parking prohibition signs, and the circular outline and diagonal bar prohibitory symbol.

Black is used as the background color on horizontal arrow One Way signs. Black is used as a message color on white, yellow, and orange signs.

White is used as the background color for most regulatory signs, except Stop signs. White is used for the legend and border on brown, green, blue, black, and red signs.

Orange is used as a background color for construction and maintenance signs.

Yellow is used as a background color for most warning signs unless orange is specified.

Brown is used as a background color for guide, information, and recreation signs.

Green is used as a background color for state and federal highway guide signs, milepost markers, and as a legend color with white background for permissive parking regulation signs.

Blue is used as a background color for information signs and related motorist services on state and federal highways

Sign Shapes

As per the MUTCD and EM7100-15, signs for motorized trails should conform to the following standard shapes.

Letter and Symbol Sizes.

For motorized trails, the minimum letter size is 2 inches using an ASA Series C font and the minimum symbol size is 12 inches. Note: Consider the intent of the sign, rider speed, and viewing distance when determining appropriate letter sizes. A 2-inch letter is difficult to read from a moving vehicle or from any distance, but a 3-inch letter is quite legible.

Sign Sizes.

The minimum size for warning and regulatory signs is 12 x 12 inches. Smaller signs should not be used unless the rationale is documented in the project file.

The USDA Forest Service Sign and Poster Guidelines EM7100-15 is a recommended resource for roads and OHV trails. It contains a plethora of additional information on sign messages, abbreviations, number of lines per message, the use of arrows, letter size in relation to speed, sign substrates, etc.

Recommended Sign Guidance

For safety, durability, and professional appearance, the following general sign guidelines are recommended:

• Use retroreflective backgrounds on signs so they appear to be the same shape and color by night as by day. Even if there is no night riding, search and rescue operations frequently occur at night.
• Put a border on the signs.
• Order signs with rounded corners and pre-drilled holes for attachment.
• Mount signs on posts or markers, not on trees.
• Only one warning or regulatory sign should be mounted per post.

All signs with decals, letters, or numbers can be covered with clear plastic tape that wraps over the top of the sign. This helps prevent snow shear; protects the sign and decals from UV decay; and protects the sign from damage by weather, wildlife, or vandalism. This protective sheeting can triple the life of the sign or marker.

At the time of final design or construction, a Sign List should be developed that lists all the signs and markers needed on a particular segment of trail. Once the signs are installed, GPS coordinates can be added so the Sign List can serve as a complete sign inventory as well as a maintenance tool. This list aids in the correct assembly and installation of the signs.

Signs up to 18 x 18 inches should be attached to posts with 5/16 x1¼ inches hex head lag bolts with washers. Larger signs should be attached with 3/8 x 1½ inches hex head lag bolts with washers. For all signs that are near roads, trailheads, staging areas, campgrounds, or other areas with public access, consider vandal-resistant hardware. To avoid damage to the sign face and decals, the holes for these screws need to be pre-drilled and care should be taken not to over-tighten the bolts or screws.

For quality aesthetics in most forest settings, it is preferred to have signs with brown backs since they blend with the landscape better and look more natural. This is an advantage of using brown polyplate as a sign substrate. In an urban or industrial setting like an OHV park or MX track, other background colors may be appropriate.

Things That Harm Signs

When selecting sign materials, there are several environmental factors to consider.

Wildlife. Porcupines eat wood signs, so avoid using wood if these animals are prevalent. Deer and elk will use signposts to rub the velvet off their antlers. A 4 x 4 inch wood post can be rubbed to a toothpick in a few years. Fiberglass or metal may be a better alternative.

Livestock. Cows will scratch themselves by rubbing on signs and can easily break a sign or deface it. Consider using thicker materials and be sure to cover the signs with clear overlaminate sheeting to increase durability.

Ultraviolet light. The sun’s UV rays will fade colors, damage adhesives so decals peel and multi-layer signs delaminate, and bleach the resins out of fiberglass so it fades and rots. When possible, order materials that are UV stabilized. Cover all signs and markers with clear overlaminate tape.

Weather. Rain will eventually saturate wooded laminate signs like plywood. Heavy hail can cause sign sheeting or decals to peel. Snow shear is a tremendous force that can also peel away the sheeting or decals. Extend the life of your signs by using clear overlaminate sheeting.

In areas that are prone to high winds or tornadoes, consider using thicker substrates and heavier bolts to attach signs to posts. Be sure that signposts and markers are thoroughly embedded in the ground. This can be difficult in hardpan or rocky ground so drilling may be needed to obtain an adequate depth.

Human exposure. Graffiti, bullet holes, or breakage can be a common problem in some locations. Having a clear overlaminate sheeting will aid in the removal of graffiti. Regular inspection and maintenance are needed to address other issues.

Common Mistakes.

There are several common mistakes that all management teams make when considering what signing to use on their trails. The photos below highlight the mistakes and give suggested solutions.

Good ideas

There are also several good ideas for signing.

Trail Maps

As in signing, trail maps provide information, orientation, education, and safety messages. Riders may read the map information around the campfire or on the way home, but when first arriving on site, riders will make a beeline to the map so they can plan their route and start riding. In this scenario, the primary function of the map is orientation. As such, there are three critical factors: 1) the information on the map must match the signing on the ground; 2) the base map data must be recent enough to agree with the database used in most GPS units; and 3) maps must be available by handout or in a map box.

If there isn’t staff, a host, or a volunteer available to hand out maps and education material, a map box is the next best thing. Think of that box as a way to personally hand a map to the customer.

Though maps can easily be loaded onto mobile electronic devices, the paper map will never become obsolete because it can be wadded up and stuffed in a shirt or fanny pack; used when wet, muddy, or extremely dusty; and can survive a day of being bounced around on the trail.

A good, user-friendly trail map should have as many of the following elements as possible.

• The larger the scale, the better. 1 inch = 1 mile is good, but a larger scale allows more information to be displayed on the map and gives the rider a better sense of distance.
• Township, range, and section lines or UTMs (Universal Transverse Mercator) aid in navigation and orientation and are helpful for search and rescue operations. Most riders are GPS savvy and prefer maps with UTMs.
• US National Grid coordinates (previously US Military Grid) can be used in a GPS or as coordinates along the edges of a map, similar to atlases so people with or without a GPS can find their location between the signs and the maps. Emergency response personnel can use the same coordinates in their system to easily find lost or injured recreationists.
• GPS coordinates for trailheads, campgrounds, shelters, or other key features also help riders orient and navigate.
• Topography contour lines or shaded relief. Riders tend to seek the trails with the most elevation change and will always go to the highest point on the trail system.
• The trails labeled by name or number with difficulty indicated by color or symbol and travel direction (one-way or two-way).
• Having the mileage between trail junctions is helpful in planning the day’s ride and helps orient the riders as to the scale of the trail system.
• The allowable vehicle uses on each trail or all trails as well as allowed non-motorized uses. These can be shown with symbols on each trail, marked in the legend, or shown elsewhere on the map.
• All routes with indicators showing if they are open or closed to the designated uses. These aid in navigation and orientation. Access routes can be used when something goes wrong and riders need to find an alternate way back to the trailhead, or when there’s a major breakdown and riders need to find the nearest vehicle access to retrieve a machine.
• Trailheads, campgrounds, shelters, viewpoints, play areas, interpretive sites, and other features or destinations identified.
• Key natural features labeled for orientation: mountains, lakes, major streams, etc.
• A good and complete legend.
• Access information from the nearest population center.
• A welcome section with brief information about the trail system.
• Emergency phone numbers, agency contact information, how to report a fire, websites, 24-hour hotlines, etc.
• Rules, restrictions, operator responsibilities, vehicle equipment requirements, seasonal closures, etc.
• Any fees to use the site.
• Hours of operation if day use only.
• Rider education, rider ethics, and safety information.
• Noxious weed information, important resource protection information for soils, plants, wildlife, fire, etc.
• Land ownership, wilderness areas, restricted areas, closed areas.
• A description of the key signs riders will encounter on the trail.
• A recreation opportunity guide (ROG). Some areas use ROGs to give the rider a brief description of what experience to expect on each trail, especially in relation to difficulty. What does a black diamond mean on this trail? The ROG will explain it.
• Camping and campfire information, group camping rules, firewood gathering rules, etc.

Websites and Social Media

The phrase “Know Before You Go” has never been easier to achieve. Most riders get maps, directions, weather, and other information from websites before they leave to go riding. Certainly, the cyber information era can be a blessing to management if management chooses to use it effectively. A website can have rules and regulations, downloadable maps, fee information, equipment and licensing information, current conditions, a volunteer page, links to weather and fire conditions, etc. The list of possibilities is almost endless.

A good website will be simple and easy to navigate. The general public should be able to locate the information easily on the site with a few simple clicks. Long pages where the public needs to scroll several times in order the find additional information usually causes important information to be missed. A higher number of shorter pages with a good menu or menu page is better.

Many maps are now geo-coded. This means a map can be downloaded to a smartphone or similar device. Map apps with the ability to read these maps use the internal GPS of the smartphone to track the rider’s location on the downloaded map as the trails. The website should have both the maps and a list or link to possible apps which will work with the geo-coding on the map.

Social media is the number one way to reach younger people. Facebook, Twitter, and Instagram can get important messages to younger riders and get them out to your trails.

Agency Staff

Any manager’s dream is to have the funding to have adequate staff who are conscientious, knowledgeable, professional, and customer service-oriented. However, as budgets tighten, that dream becomes less of a reality.

From the public’s perspective, having personable agency staff on site provides:

• A sense that the agency cares about them and their activity.
• Face-to-face communication personalizes the agency and can breach the sometimes daunting impersonal wall of bureaucracy.
• A sense of increased security.
• An understanding of agency challenges that can potentially lead to increased volunteerism.
• Visible evidence that the site is actively managed.

Contracted Site Hosts

When there is inadequate agency staff, non-agency site hosts can help fill the gap and provide a valuable service. Site hosts must have the social skills to effectively handle a variety of situations and they must have a friendly customer-service attitude. Hosts must be trained and have dependable communication with management and law enforcement. Since hosts are more likely to be on-site when the riders are present, they can be especially beneficial on projects that include a change in rider ethics, rules, fees, and riding opportunities.

Other advantages can include:

• Increased “agency” visibility
• Increased rider education
• An increased sense of visitor security
• Increased compliance
• Decreased vandalism
• An increase and more effective collection of fees
• Increased public image and awareness of active management

People prefer personal contacts over machines. Friendly customer service helps to provide for the riders’ needs.

Volunteer Trail Ambassadors and Rangers

Except for fee collection, a volunteer trail ambassador program can have all of the same benefits of a site host. Ambassadors need to be able to ride, but like a host, the most important prerequisite is possessing good social skills. To be effective, a personal encounter must have a positive outcome, and that is determined by the skill and attitude of the ambassador (or host). Ambassadors must be trained and should have a probationary period of supervised encounters to ensure quality and positive outcomes.

Here are some considerations for trail ambassador programs:

• Ambassadors must have a designation, ride in pairs, wear PPE, have a check in and check out procedure, and have dependable communication with law enforcement or management.
• Ambassadors must recognize the line between education and enforcement. The role of an ambassador is strictly education. They do not do enforcement and usually do not collect fees.
• Sometimes personal ownership and commitment can lead to a vigilante attitude, which is neither positive nor productive. Management must weed out those people.
• Since ambassadors can roam the trails, they provide a wider agency presence that is outside of the trailhead.
• By riding the trails, they are providing monitoring and can report trees down, signs missing, off-trail use, erosion, invasive species, or other trail issues. This can be a huge value to management.
• Since they are dressed like riders, they can apply effective peer pressure because riders will associate with and listen to other riders.
• Ambassadors can be trained to perform complimentary tech check inspections.
• Ambassadors can develop pride by being part of an elite group that provides an important function. Their positive attitude can stimulate volunteerism.
• Ambassadors can also serve as effective agency representatives at fairs, trade shows, sportsmen shows, professional OHV events, and other venues.

Adaptive Management

The sub-continuum of implement, evaluate, make changes, and re-evaluate is called adaptive management. A trail is placed in a dynamic environment, and change of some type is inevitable. The need for trail changes should be anticipated in the planning process, and it is to the managers’ advantage to include adaptive management verbiage in the initial environmental document.

There are several adaptive management tools available, including mitigations, restrictions, relocation, reconstruction, using existing infrastructure, entrance management and, when necessary, closure.

Closure Options

There are many closure options available to managers, each with a different focus and effect. Before any closure is implemented, ensure that there is sound justification, that there is an implementation and education plan utilizing the 4Es, and that the ramifications of the action are thoroughly examined. Riders will get displaced. Where will they go and what impacts will occur? Is there adequate personnel and funding for enforcement? Will the closure damage relationships with partners? For every action, there is an equal and opposite reaction. If a trail gets closed, there will be a reaction. Plan for it and be prepared to manage it.

Permanent Closure. To protect resource values or public safety, permanent closure is certainly a management tool. There are sensitive areas that need to be protected and there are non-sustainable trails that cannot be made sustainable. Closure is often seen as the easiest and cheapest management option. While it is the quickest option, it is often not the easiest or the cheapest in the long run. Displaced riders will need to go someplace. This could over-tax the few riding areas that are left, causing resource damage and conflicts.

A key point is, whenever possible, managers should not close something before opening something else of equal or greater mileage, quality, seat time, etc. When riders realize that they can still get from Point A to Point B or have a new higher-quality opportunity, compliance with the closure will significantly increase.

Sticking up a sign or a barrier to close a trail is not effective application of the 4Es. An effective closure should include a barrier, signing, and ripping and disguising of existing routes (Engineering). Education on the rationale for the closure should be posted on the map, kiosk, websites, and other media as appropriate.

Emergency Closure. Management can implement an emergency closure any time there is extraordinary risk to public safety or resource protection. This could be due to an active forest fire, a severe weather event, or protection in the aftermath of those events.

Temporary Closure. A temporary closure is not recurring and can be used for maintenance, trail reconstruction, extreme fire danger, vegetation management activity, to protect the trails from damage when the trail treads are saturated, for range or livestock activities, for a special use permitted event, etc. When a change in trail use is not permanent and not recurring, it now becomes critical to successfully implement the 4Es. The word must quickly get out on the ground and in the media.

Temporal Restriction. A temporal restriction can be used to separate trail uses and users who are having difficulty being compatible with each other. An example could be that a trail is open for OHVs one week and open to hikers the next week. Here, the manager is placed in a position of conflict management and it will only be successful if: a) there is total agreement with all trail users that this is what they really want; b) if both or all trail groups are treated equally; c) if all share equally in the trail maintenance; d) if all groups commit to self-policing themselves; and e) if the 4Es are successfully implemented. This management option is an intermediate option between a trail being open to all groups and a trail being closed to one group. Most managers choose not to take this step because of the complexity of education and enforcement.

Mitigations

Mitigation measures reduce the potential impact or the risk of impact. A seasonal closure is a mitigation measure to reduce the risk of impacts during a certain time period. Some resources like marshes, riparian areas, or subsurface cultural sites need to be avoided temporarily, but don’t have to be avoided year-round. Mitigations can allow or restrict trail access while minimizing risk to a resource.

Seasonal Closure. A seasonal closure is a recurring closure that regulates vehicle access. The three main uses are: 1) wildlife related, including big game winter range, fawning or calving season, and nesting season; 2) soil related, including closures during spring break-up or fall freeze-up; and 3) vehicle related, including closures to wheeled vehicles to allow access for over-snow vehicles. Any time there is a change in vehicle access, the effective use of the 4Es, especially education (signing, mapping, etc.), becomes more essential to ensure successful implementation.

Avoidance. When a sensitive resource is encountered, sometimes the easiest option is just to avoid going there. This usually simplifies the environmental analysis and minimizes risk to the resource. If the resource can’t be avoided,use of design, structures, or other tools may provide adequate mitigation.

Monitoring. Sometimes monitoring can be used as a mitigation. A trail tread depth, for example, could just be monitored. When and if it gets down close to the depth of the resource, then trail hardening or structures could be implemented as additional mitigation.

Monitoring can be used to gain knowledge. Perhaps a sensitive or potentially sensitive bird decides to make a nest adjacent to an existing trail. Rather than implement avoidance, why did the bird choose to nest there and will the OHV trail negatively affect a bird which nested near its activity? These could be answered through monitoring if the manager and the resource specialist are comfortable with the risk.

One issue with monitoring is that there must be the budget, skilled personnel, and time for the personnel to perform the monitoring. When budgets get tight, monitoring is often the first thing to get put on hold. As personnel come and go, monitoring plans can sit on the shelf and fall through the cracks of implementation. In trail management and monitoring it is important that managers do what they say they are going to do in order to build trustful working relationships. That doesn’t stop at planning, it follows through the whole Great Trail Continuum.

Interpretation. Sometimes, interpretation can be used as a mitigation measure. With interpretation comes potential risk to the site since people will be stopping and spending time there rather than riding through. But interpretation is education and that has value. The thought process is that some risk will be accepted here, and by educating the public, there will be reduced risk elsewhere. Sometimes people will give more respect to a high quality area that has interpretation than to an area where they don’t understand the value of the surroundings. Interpretation can be expensive, but it is a valuable tool and one that is not used often enough on OHV trail systems. Interpretation enhances the rider experience, extends the length of that experience, and can help protect the resource.

The public has a strong desire to learn about history and the natural environment. Including interpretation is one of those extra steps that adds the WOW factor and turns a good trail into a great trail.

Interpretation can also open the door for some creative partnerships and funding opportunities.

Structures. Though structures are a design element, many structures are mitigations for issues brought up during the planning process. Bridges are a mitigation to help protect water quality. Barriers and fencing can be mitigations to help protect sensitive areas. Cattle guards help mitigate the range issue of gates being left open. Implementing structures like boardwalks and puncheons can allow access through or over sensitive areas while still protecting the resource. Trail hardening can be used to help protect subsurface resources. The use of those structures not only helps protect the resource, they can greatly enhance the quality of the riding experience. Structures help provide a win-win scenario.

Restrictions

Using restrictions is a form of adaptive management to protect both the resources and the riding experience. There are two forms of restrictions. Vehicle restrictions are restrictions regarding the actual machine. Equipment restrictions are restrictions on accessories or other equipment on the machines.

Vehicle Restrictions. Vehicles are most commonly restricted by their width or type. OHV trails which are open to vehicles 50 inches or less in width could allow OHMs, ATVs, and smaller ROVs on the trail. Trails can also be open to one or more designated machine types. Single-track trails are often restricted to OHMs only. A combination of type and width restrictions can be used. Some 4WD-only designated trails have width restrictions to preclude modified rigs with excessive width.

Vehicle widths are restricted to: a) maintain narrow clearing width to enhance the trail experience; b) increase rider safety by limiting the size of a vehicle that may be encountered; c) protect a trail prism that wasn’t built wide enough or may not have the durability to safely accommodate wider and heavier vehicles; and d) increase rider experience by providing more difficulty levels in the trail system. Many existing NEPA documents do not allow wider vehicles or a vehicle type which wasn't expressly analyzed in the document. Changing those documents could re-open the door to appeals and litigation.

It is important to note that even though state or provincial laws may allow certain vehicles, trail managers usually have the option to be more restrictive when necessary and justified to protect resources or public safety. These messages are conveyed through the 4Es using effective entrance management structures and communicated to the riders before they get to the trail.

Equipment Restrictions. Restrictions which include items like requiring spark arresters, limiting sound emissions, requiring safety flags, and requiring fire tools on vehicles of a certain size like ROVs and 4WDs are examples of equipment restrictions. As with vehicle restrictions, land managers usually have the prerogative to be more restrictive than state or provincial laws allow when it is justifiable. The risk of fire is almost always raised as an issue, and sound can be an issue, so spark arresters and silencers are easy mitigations for these concerns. Safety flags are often required in dune areas to increase the visibility of approaching vehicles.

The trail tread is a valuable resource and the force of displacement acts on that resource. There is often discussion on whether the tire type should be restricted. Many people believe that more aggressive tires create greater displacement. However, as the U.S. Forest Service tire study has shown, the depth of the tread is not a factor in the amount of displacement on a trail. Knobby tires are designed to grip, not to tear or slip. They can be likened to golf shoe spikes which help keep feet from slipping across the surface and creating divots.

Impacts from tires are caused more by the mentality of the rider than by the aggressiveness of the tire, so management effort is better spent on the 4Es to improve rider ethics and promote peer pressure than on enforcing a restriction. Tread Lightly!’s, “Use It but Don’t Abuse It,” and “Ride It, Don’t Slide It” can be good education messages.

Relocation and New Construction

Relocation is a tool that can be used to avoid a sensitive resource or move a section of non-sustainable trail to a more suitable location and alignment. Too often, managers pour money into multiple bandages for a trail that cannot be fixed when it would be less expensive in the long term to relocate the trail. Relocation is a tool that can protect resources, enhance the rider experience, and increase rider safety.

Relocation, of course, involves new construction, which may require additional environmental review and documentation. Because of this, some managers do not consider relocation as an option. However, if the trail still goes from Point A to Point B and the effects of the relocation fall within the scope of effects analyzed in the environmental document, the relocation could still be meeting the intent of the original document and the process to implement the relocation could be relatively simple without opening the door to appeals and litigation. Adaptive management verbiage in the environmental document can facilitate the trail relocation process.

Reconstruction

Reconstruction can be used two ways: 1) to put a trail back into the condition it was in when it was first constructed (essentially performing backlog maintenance) and 2) to upgrade the original condition by re-grading; reshaping; and adding or improving structures, signing, facilities, and segments of trail.

What is the lifespan of a trail? It depends on multiple factors like soil type, use level, type of use, climate, number and type of structures, etc. All trails require maintenance, but at some point, the trail may degrade to the point where routine maintenance will be inadequate to maintain the functionality of the trail. At that point, reconstruction, or heavy maintenance, is required.

Utilize Existing Infrastructure

There us usually a plethora of existing roads and trails, but the goal should be not to maximize the use of existing infrastructure, but to examine what is available and creatively incorporate those sections that fit with the goals for the trail system. The key is variety in any form: scenic, tread surface, speed, tread width, destinations, vegetative, topographic, and interpretive opportunities, commercial access, etc. Providing an imaginative mix of experiences is what creates a quality trail or trail system. Trails are all about fun.

Structures. Utilizing or sharing existing structures is a great way to reduce project costs as well as reduce the number of structures on inventory. Sometimes, it requires creative solutions to use existing structures, but the benefits are worth the effort.

Natural Surface Roads. The use of roads can be seen as an expedient and low-cost way to provide trails. There can be many benefits, but there can also be many traps. Land managers have the option to use roads or not, and like existing structures, why not? The three main issues with roads is 1) the extent to which they are used, 2) the size of their tread watersheds, and 3) and the quality of the experiences they provide. If the road is being closed to mixed-use, consider using an existing road corridor and turning it into a trail rather than relying on the road as is.

It is important to remember that OHVs are not designed to be used on paved surfaces. When considering using roads as trails, only natural surface roads should be considered.

Use Natural Surface Roads as Trails. Roads are an existing infrastructure. Many state and provincial laws as well as agency regulations allow OHV use on roads, especially low standard or minimum maintenance roads. A great trail provides for the riders’ needs. With roads, a key point to remember is that they can provide two types of experiences, transportation and recreation. The experience must match the riders’ desired experience for the trail or it won’t meet the riders’ needs.

Convert Natural Surface Roads to Trails. Increasingly, roads are being closed to reduce road densities and reduce road maintenance costs. Often, this can present an opportunity to convert roads into trails. This is a good tool especially when options for creating new trails may be limited. There are many pitfalls of roads, including long sustained grades, infrequent drainage, and large watersheds; but when properly done, many roads can be converted into high-quality trails with high-quality experiences.

Convert Rails to Trails. Railroad grades can be too fast, too straight, and too boring, but this book is about WOW. What makes a great trail great? Traveling over a 150-year-old wooden trestle and looking 500 feet down through the ties to the river below or entering a dark tunnel. That is WOW. If there is an opportunity to incorporate that, seize it.

Trails. As in roads, there can be benefits and traps. Using existing trails can have the same issues as using roads: the extent to which they are used and the quality of the experiences they provide. Most existing trails were not designed, so primary concerns are their sustainability and whether they go where the planner needs them to go. Many user-created trails go up the hill whereas sustainable trails go across the hill, and the biggest trap that a manager can fall into is to assume that user-created trails meet the users’ needs. Most do not.

Entrance Management

Entrance management is a tool that managers often overlook. Implementing effective entrance management:

• Provides rider education by indicating trail number, difficulty level, and allowed vehicles.
• Sets rider expectations through well-engineered barriers and filters.
• Reduces conflict by setting rider expectations.
• Sets the stage for enforcement by posting travel management signing and any pertinent restriction or closure signing.
• Increases rider safety by immediately indicating the skill level needed to negotiate the trail.
• Reduces impacts created by unskilled riders.
• Potentially reduces the number of riders on a trail, which can keep a marginal trail on the sustainable side of the fulcrum.
• Reduces or eliminates trail widening caused by over-width vehicle use.
• Increases the rider experience by maintaining the designed tread width, reducing the number of riders, and protecting challenge features.

Every one of these items is an element of a great trail and of great trail management. Effective entrance management epitomizes the application of the 4Es; it helps ensure a quality recreation experience and reduces the managers’ risk.

Administrative Tools

Below is a list of the management tools that can help build a successful program.

Partnerships. Having broad-based support for the project or program is imperative. Just like the Great Trail Continuum, the battle to have and keep OHV trails is never over. The stronger and broader the support base, the better it will survive attacks from critics over time. Time invested in strengthening and expanding partnerships is time well spent.

Donations. Having a broad base of partners can open the door for a wide variety of donated materials and supplies. Being in the position of asking for anything can be an awkward task, but vendors usually will not offer support without being asked. Managers who ask are usually surprised with the results. These donations not only help the program on the ground, but they serve as important sources for match contributions for grants.

Innovative Grants. Having partners helps secure grants, but having creative partnerships almost ensures grant success. Almost all resources benefit from having a well-managed, designated OHV trail system, so seek partners and grants from unlikely sources like the Nature Conservancy, Ducks Unlimited, the Rocky Mountain Elk Foundation, and Backcountry Horsemen, etc.

Volunteer Program. Having a lot of volunteer labor is another key to securing grants, especially if the labor comes from multiple volunteer sources. The organizing, training, and scheduling of volunteers takes a lot of time and energy, but again it is time well spent. Volunteers aren’t free, but for building partners, grants, and a workforce, they are essential to any successful OHV program. Volunteer trail ambassadors can increase education, evaluation, peer pressure, and agency visibility. When it comes to maintenance, whatever work can be done by volunteers, should be done by volunteers. This will build support and ownership in the program. Volunteers are a key component in successfully implementing the 4Es. Like donations, volunteers usually don’t step forward on their own, they need to be asked.

External Relations and Politics. This would include anyone outside of the agency: dealers, local and regional clubs and associations, state or provincial OHV program and grant managers, community leaders, and stakeholders. Conducting a group or one-on-one field trip to the project presents a good forum to build and strengthen these relationships. Time spent here could lead to additional partners, grants, and volunteerism.

Internal Relations and Politics. Dealing with internal politics can be far more challenging than external politics because of the day-to-day contact and interaction with co-workers. However, that effort is more than worth it when it comes down to gaining time commitments from essential personnel like resource specialists, obtaining labor from fire or smokejumper crews, or securing the fair share of a tight budget.

Permitted Activities. Permitted activities could include speed and non-speed events, jamborees or rallies, charity fundraisers, and special training or education events. There are many benefits to having permitted activities: clubs and the public enjoy them, so having them increases the external political connections and relations; clubs often rely on events as primary fundraisers; activities can stimulate interest, support, and volunteerism; they bring public and media exposure to the trail system that can help market the system and increase awareness of successful OHV management; they can provide an economic benefit to the community; and they can strengthen external relations and political connections.

Legislative Changes. Sometimes current laws are outdated or too restrictive to allow managers the flexibility they need to effectively manage the use. The only way to fix that is to work within the system to try to implement changes. Field trips with legislators, stakeholder group advocates, or state or provincial agency personnel can help show them the rationale for needed changes. Working with clubs and associations on these efforts can be well worth the time.

Integrated Resource Management (IRM). IRM involves the coordination and cooperation between an OHV program and the activities of other resource entities within the agency: fire, other recreation, silviculture, range, law enforcement, engineering, wildlife, botany, cultural resources, etc. It takes effort to develop those internal relations and to get involved in the planning and execution of all of these other resource activities. But the trail is also a resource and the OHV program has or should have parity with any other program. Because trails are easy to traverse, they often get used as boundary lines for other activities, but those lines can affect the integrity of the trail and the quality of the trail experience. While a buffer strip usually isn’t required, what is desirable is a mosaic that creates variety.

Here are some scenarios that could be avoided or minimized with IRM:

• The use of trails as skid trails or temporary roads.
• Having trails used as fire lines.
• Having trails used as timber unit or cut block boundaries.
• Having fence lines installed that cross the trail on steep grades or curves.
• Having sight lines and corridors opened up through vegetation management that can invite off-trail hillclimb use.
• Improper closure of temporary roads and skid trails that invite off-trail use.

And some benefits:

• Having advance notice of fire or timber harvest activities so trails can be signed and the public informed.
• Having pits and quarries shaped for use as play areas.
• Having a landing or other impacted site specifically located for future use as a trailhead or other site for OHV activity.
• Being able to relocate an undesirable trail or trail segment as a mitigation to avoid adverse impacts from the other activity.

Know the Customer. The demographics of the customer will change over time and managers can’t provide for the riders’ needs if they don’t know who the riders are or where they are coming from. A short online survey or a registration box at the trailhead can give managers valuable information that can be used to better serve the customers and provide supportive data for grant requests and other reporting.

Implement All of the 4Es

The 4Es: Engineering, Education, Enforcement, and Evaluation, have been mentioned several times in this chapter and throughout this book. Use them. Enough said.