An eye for dirt #1

7/30/2019 An eye for dirt #1

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An Eye for Dirt : TheAn Eye for Dirt : TheFundamentals of Trail DesignFundamentals of Trail Design

Presenter: John KowaleskiPresenter: John Kowaleski

TrailTechTrailTech LLCLLC

www.trailtechllc.comwww.trailtechllc.com

This series of slides will show well designed trails and some that need help. Thepurpose is to illustrate some first steps in the trail design process. This is by nomeans complete coverage of trail design, but some beginning steps to follow.


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What is a well designed trail?What is a well designed trail?

Well designed recreational trails appeal to your senses, with a variety oflandscape features that blend with the scenery. They integrate into theenvironment with minimal environmental impacts.


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they meander, follow contours, and natural topography, the trail should seemlike it has always been there and belongs there.


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Structures like this footbridge should not be too elaborate, but visually fit thecharacter of the scenery. Like a bridge made of redwood in a redwood forest.


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. A well designed trail should highlight historical features such as thesestonewalls, however keep in mind that a historical, archeological inventory of yoursite may recommend protection of significant features too..


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Seeing wildlife is one of the most memorable experiences you can have along atrail. However, a well designed trail should find a balance by minimizing impactsto wildlife too.


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Where do you start? Before you can begin designing a trail ask the Wquestions, a basic needs assessment.

Why have a trail here? What kind of trail experience do you want? What is the

purpose of this trail? Where can the trail start and end? Who will build the trail?Who will maintain it? Is this trail purely recreational, or for transportation too?Answers to these questions will develop your vision for the trail.


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Basic Design Process:Basic Design Process:

Estimate who and how many will use the trail.Estimate who and how many will use the trail. Develop design specifications, to maximizeDevelop design specifications, to maximize

enjoyment and minimize conflict, erosion, andenjoyment and minimize conflict, erosion, and

maintenance.maintenance.

Keep in mind accessibility.Keep in mind accessibility.

Research positive and negative control points.Research positive and negative control points.

Flag potential routes.Flag potential routes.

Sustainable trail design begins with these first steps.


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Different trail users influence how aDifferent trail users influence how a

trail is builttrail is built

Designing trails begins with the users. Specifications will vary for width,structures, and surfacing depending on the different users level of use, andenvironment. The next series of slides illustrates these variables.


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Hiking trails with low to moderate use can be narrow 18. Heavy use needs width,around 4 feet, for safe passing. Also, if your trail is in steep country, more width isneeded for safety. Can it be an accessible trail?


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... Corridor and tread width is needed for safe passing.


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Equestrians require overhead clearances of 10-12 feet, 5-6 of corridor width, andoften crusher fines to keep soft soils intact. Use crusher fines only if the grade is6% or less. This flat section of trail may get muddy when wet.


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Muddy trails leads to trail widening.


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Mountain bike riders like narrow single track trails for the same reasons thatappeal to hikers and equestrians: it gives them more of a feeling of being out innature. Other design specifications include climbing turns, rolling dips, increasedline of sight and occasional obstacles to slow speed to give the trail a technicalfeel. Like hiking trails, width varies typically with use levels from 18"- 4 ft.Sightlines need to be considered, anywhere from 30-60 ft. on trail sections wherethe bikes can reach 15 mph. If you have very high visitation, and multi-use, youmay need a wider trail. Many agencies in the SF Bay Area restrict bikes to fireroads at 8-10 feet wide.


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Sustainable Design SpecificationsSustainable Design Specifications

Keep average grades at 10% or less. .Keep average grades at 10% or less. . Out slope trail for drainage if the soils are stableOut slope trail for drainage if the soils are stable

and the slope is


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Out slopingOut sloping

Trail tread is typically outsloped for sheet drainage. It duplicates how water drainsoff the natural slope to cause it to sheet across. Outsloping should not be morethan around 5-8 %. If you have erodeable soils or steep sidehill over 50%, youmay not be able to outslope.


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This type of turn known as a climbing turn minimizes damage frommountain bikeriding; a more gradual turn on slopes around 8% or less. For steeper slopes,consider regular switchbacks.


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Here is an example of a switchback that has been eroded. See how all thevegetation is gone; there are no anchors or barriers to keep from short cutting.


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Here is a nice looking one with vegetation barriers between the trail sections andon the downhill side too.


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Preferred drainage structure is a rolling dip essentially a change in grade cutinto the trail surface that uses little fill. It is low maintenance, and not disturbedduring re-grading of trails.


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Plan Trails with Accessibility in MindPlan Trails with Accessibility in Mind

New Forest Service Trail Accessibility Guidelines give more flexibility and clarityas to what is needed to improve access. Design your trail for accessibility, andreview the site features to assess any environmental or engineering issues. Areadditional safety measures needed.


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. such as these bumper logs and fence where there is a danger of rolling off theedge..


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Surfacing GuidelinesSurfacing Guidelines

Surface be firm and stable.Surface be firm and stable.

Use 3/8 or 1/4 minus crusher fines,Use 3/8 or 1/4 minus crusher fines,

asphalt, or concrete.asphalt, or concrete.

Consider additives for crusher fines toConsider additives for crusher fines to

increase binding, such as cement or Roadincrease binding, such as cement or Road

OylOyl a pine based resin.a pine based resin.


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Other Potential Trail Users toOther Potential Trail Users to

ConsiderConsider


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Consider special trail design measures for dog walkers. Dog off leash walking ispopular, however it may be incompatible near sensitive habitats or kids. Also,consider the disposal of waste.


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These fence barriers were installed at Fort Funston in SF to prevent dogs fromdisturbing snowy plovers and sensitive dune species.


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ATV use is one of the fastest growing sports in the country. Many organizationsare working to improve access and responsible riding, such as Tread Lightly!Locate your route to minimize noise and environmental impacts, restrict accessduring nesting, breeding, and mud seasons..expect a high level of maintenanceand enforcement, and consider looking to ATV groups to help you out with thesecosts.


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Logging- your proposed trail may become a skid road if logging is allowed. Beaware of this possibility and build into your forest management plan specificationsfor trail restoration.


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Otherwise your trail may end up like this, with brush packing for erosion control, avery uneven, obstacle filled trail tread


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Is your area fire prone? You may need or want enough trail width or a consistentgrade for fire access. Many of the trails out west were built to allow a fire crew tocarry a hose pack and other fire gear without getting exhausted going up a steepgrade.


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patrol access. A well designed trail at a grade 10% or less allows ranger orvolunteer patrols easier access.


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Geo caching, questing, is becoming very popular. Consider how your trail may beimpacted by this activity. Some geo caches disturb sensitive plant species if thecache is buried or hidden off trail. Consider signage and regulations if this activityis popular in your park.


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Downhill mountain bike riding, may or may not be a compatible use on a busytrail. An inclusive public planning process should evaluate this issue. Presently,many ski resorts allow use on their downhill runs for this activity. These ridersenjoy steep trails, however for sustainable multi-use, design your trails to followcontours, at 10% on average. You can build in some technical features forchallenge and to slow speed.


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This is what happens with too much speed, See the upper bank where the riderstake the high line?


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Positive and Negative ControlPositive and Negative Control

PointsPoints

Positive and Negative control points will effect where your trail route can andcannot go as well as design specifications. Start with map research.Ecological/historical/archaeological assessments need to be done and fieldedchecked. Avoid priority habitats such as this wood turtles.


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Online Resource DataOnline Resource Data-- MassGISMassGIS

0


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Wetlands.can be crossed with bog bridges and boardwalks, however, is there adrier alternative? You may decide to avoid these areas. If you go there, wetlandsdelineation, Conservation Commission review, permitting requirements, andmitigation at 2 or 3:1 ratio may be part of your trail project.


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Bog bridges are OK for light use, shallow saturated soils, however, more subjectto frost heave than boardwalks. They can be staked down to minimize frostheave.


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Turnpikes are recommended for wetlands subject to only seasonal saturation.Safer, more natural in appearance, easier to maintain, more durable and longlasting. However, construction involves more initial soil and vegetationdisturbance.


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Stream CrossingsStream Crossings-- BridgesBridges

Bridges are your most expensive design specification and most difficult controlpoint. Significant crossings require engineering, and ecological assessmentsby biologists and hydrologists. Is your stream a Class 1 anadromous fishbearing stream? Your bridge will require local, state and Army Corps 404permitting.


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Bridges vs. CulvertsBridges vs. Culverts

Bridges are less disruptive to the environment.Bridges are less disruptive to the environment.but more costly, require safety inspections andbut more costly, require safety inspections and

regular maintenance.regular maintenance.

Culverts are more likely to fail, less expensive,Culverts are more likely to fail, less expensive,

must have correct sizing, inflow, outflowmust have correct sizing, inflow, outflow

protections, proper grade, critical dips, andprotections, proper grade, critical dips, and

perhaps trash racks on upstream side.perhaps trash racks on upstream side.

Culvert sizing has usually been based on watershed size and flows, however,most fail due to debris flows.


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Culverts work well for minor drainages if maintained regularly, and have adequateheadwall protection.


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For major waterways culvert failure can have significant damage.


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This vernal pool may not be visible in the fall or even on a map field locatethese features and minimize impacts with an adequate buffer, up to 100-200 feet.


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Beaver dams, a growing trail impact in new England. Many historic trail routes arein flood prone areas. Learn from these mistakes, by choosing your route wellabove the floodplain.


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Slide prone slopes, building trails across these slopes makes them moreunstable! Be prepared to do lots of maintenance! Try to route the trail above orbelow this point.


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This trail failed because it was located on a steep slope with heavy clay soils onan aspect facing southwest where the wettest storms came from. Heavy rainssaturated the ground causing an oak tree to topple at the toe of this steep slope,losing this trail section completely.


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Flagging Potential RoutesFlagging Potential Routes

Flagging Fundamentals

This is a real art! Review your route on topo maps, talk to people who know thearea, explore, flag potential routes, field locate control points and features ofinterest. You may have to do this at different times of the year, explore, explore,explore.If you do your flagging right, there will be few construction problems.


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A Few Flagging GuidelinesA Few Flagging Guidelines

Keep it under 10%.Keep it under 10%. Locate switchbacks on natural benches.Locate switchbacks on natural benches.

Avoid flat areas, its harder to get the water off.Avoid flat areas, its harder to get the water off.

Avoid slide prone slopes. Ask for geotechnicalAvoid slide prone slopes. Ask for geotechnical

assistance.assistance.

Include a variety of landscapes.Include a variety of landscapes.

Find your best stream crossings, and work off ofFind your best stream crossings, and work off of

them.them.


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Resources to Consider:Resources to Consider:

Forest Service Standards and SpecificationsForest Service Standards and Specifications Recreational Trail Design and ConstructionRecreational Trail Design and Construction

Specs. University of MinnesotaSpecs. University of Minnesota ExtentionExtention

AMC Guide to Trail BuildingAMC Guide to Trail Building

Trail Design and Management Handbook, byTrail Design and Management Handbook, by

Troy Scott Parker.Troy Scott Parker.

Building Naturalistic Trails, by Troy Scott Parker.Building Naturalistic Trails, by Troy Scott Parker.

Review these resources for design specifications. There are some regionaldifferences, but many of the specs are the same.


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Start recruiting your work force, you are getting close to designing your trail!

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An eye for dirt #1