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Best Management Practices for Erosion Control During Trail Maintenance and Construction

From the State of New Hampshire Department of Resources and Economic Development, Division of Parks and Recreation, Bureau of Trails

Trail construction and maintenance may involve impacts to wetlands and other natural resources: an understanding of these impacts and methods to minimize them.

Purpose

In addition to providing recreation, trails foster an appreciation and respect of nature. Trail construction and maintenance may involve impacts to wetlands and other natural resources. This publication attempts to create an understanding of these impacts and provide the methods necessary to minimize them. It has been developed as a reference tool to help public land managers, trail clubs, landowners and recreational trail users work together to protect our state's natural resources. It is necessary to develop erosion control plans for trail projects to minimize erosion, sedimentation and resulting water degradation prior to the initiation of construc

Trail planning guidelines

The ideal recreational trail is one that requires minimal maintenance. When planning a trail and its construction, you should take advantage of the natural features of the environment rather than transforming the landscape to meet the proposed project's needs. The materials that will be used, the construction and maintenance techniques, and the size of the trail project will help identify the scale of the environmental impact to soils and wetlands.

The best wetlands protection is avoidance. Should modification to the landscape be required, it is imperative to minimize soil disturbance near wetlands. The first step in trail planning is to visually inspect the area. In general, look for routes that are dry, of moderate grade, and in need of little terrain modifications in order to minimize potential erosion and sedimentation problems. Survey the trail during wet months!

Trail design

Poorly designed, located, constructed, and maintained trails can cause significant erosion and sedimentation problems. The first rule of trail design is to avoid crossing wetlands, or other sensitive areas, such as vernal pools. This may mean planning a longer route that minimizes the impact to environmentally sensitive areas, as well as reducing the need for future remedial actions.

Where wetlands crossings are unavoidable, crossings should be properly designed and placed at the narrowest wetland location. Trail design should always ensure that runoff water and drainage from the trail is collected in a stabilized area or sediment basin. Natural drainage patterns should not be disrupted or moved, as the runoff water and surface water may be providing moisture to wetlands downslope or downstream. The design of these drainage ways ensures that runoff volume and velocity is handled without risk of erosion or sedimentation. Surveying the trail during wet months will help determine drainage patterns and the location of wetlands and saturated soils.

Water is a powerful attractant to people. Typically, many trails have been built too close to the water, with resulting environmental and maintenance problems. Good trail design can balance the desire to be near water with environmental protection by incorporating scenic viewpoints, vegetative buffer zones, and by minimizing the number of wetland crossings.

General guidelines

• Know the type of trail being constructed. Design for all potential uses.
• Good planning and design of recommended trail work should prevent many potential erosion problems.
• Whenever possible, use vegetative means of erosion control, such as seeding or planting small trees or other ground cover.
• Avoid using heavy equipment whenever possible, thus reducing the amount of disturbances to the natural resources.
• Certain forms of recreational trail use can create serious erosion and sedimentation problems. It is essential to integrate erosion control measures when planning, constructing, and maintaining trails, and to assure the measures are appropriate for the type of recreational use the trail receives.
• The steeper the slope, the greater the potential for problems.
• Multiple-use trails should be designed to the most limiting standard. For example, a snowmobile and cross country ski trail design should not exceed 20% slope, the maximum grade guideline for cross country ski trails.
• The following chart consists of guidelines for recommended grades for recreational trail use which should be considered during the planning and design process.

Trail construction and maintenance

• Before beginning any trail construction, install necessary measures to minimize and prevent erosion.
• Stabilizing slopes, creating natural vegetation buffers, diverting runoff from exposed areas, controlling the volume and velocity of runoff, and conveying that runoff away from the construction area all serve to reduce erosion.
• Careful trail planning and design will create a stable trail that will result in fewer problems with soil erosion and sedimentation.
• During trail construction, minimize the amount of soil disturbance at stream crossings.
• Trail construction is best done during the dry months when soil saturation and water levels are at their lowest.
• The three most important factors to consider during trail construction are the character of the land itself (soil, slope, and vegetative cover), the type of expected use, and the volume of that expected use.
• Some trail construction areas may need to be stabilized if heavy traffic is expected on the trail.
• Install temporary erosion control measures such as hay bales before construction begins. Keep them in place and maintained during construction and remove them only after the site has been stabilized.
• Trails through wet areas may have to be closed during the spring or other wet periods. Plan an alternate route, if possible.

Attached document published January 2004