Parks and Recreation System Master Plan Update (2016) parks_and_recreation_system_master_plan_update_oct | Page 480

Increase bank stabilization in riparian areas by planting native species with dense root
systems that will help anchor the soil.

Aim to surround all riparian areas, hiking and horse trails, and forest roads with
undisturbed to aid in storm water and sediment runoff management (Lacey, 2000).

Design and follow best management practices for trail construction with the purpose of
erosion control.

Aim to contour the buffer area surrounding all riparian areas and trails to avoid
concentrated storm flows, being sure to periodically remove sediment berms that
develop.
Table 9. Management guidelines for erosion control.

Erosion Control Management Practice 1: Make wetland restoration a priority. Restoring
riparian areas for the purpose of storm water management will slow the stream flow, slowing
further erosion. Parks should highlight wetland restoration as a high priority for erosion control.
Erosion Control Management Practice 2: Aim for all trail design to mitigate against erosion.
New trails in natural resource parks, natural resource fragments, and all parks should allow
visitors to enjoy nature while also protecting the resource. For that reason, new trails must avoid
the habitats of rare and/or threatened flora and fauna, riparian and wetland areas, and steep
terrain for erosion control. It is reasonable to require that all new trails be surveyed in the wet
months (October through April) in order to ensure that designers are fully aware of the impact
the trail will have on existing hydric soils. The grade of trails is also important to consider, as the
lower the grade the less likely soil erosion will occur. Table 10 shows the recommended trail
grades for all new trails in natural resource parks and fragments. Presently, ATV use is
prohibited in Metro Parks and Recreation properties and thus recommended trail grades for
ATVs are not included in this document.
Trail Type
Hiking\Walking
Grade
2 - 12% sustained grades with short durations
of steeper slopes
Mountain Biking
Maximum average slope of 10%
Equestrian
5% sustained grades with short durations of
steeper slopes (up to but never exceeding 8%)
Table 10. Recommended trail grades (New Hampshire Department of Resources and Economic
Development, 2004; International Mountain Biking Association, 2007).
Erosion Control Management Practice 3: Aim for all trail construction to minimize erosion. In
addition to designing suitable trails, the construction must also allow for the movement of water
around and beneath the trails. In general, trail construction is best done during the dry months
(May through September) with minimal soil disturbance at stream crossings for better
stabilization of the trail and less impact on the surrounding environment. Many options are
available for trail construction (Table 11).
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