Brush Trench POLLUTANTS ADDRESSED: Sediments, Nutrients and Organics, Salinity
DESCRIPTION: Bundles of willow cuttings (or cuttings of other available species) are placed in a buried trench along the top of an eroding stream bank. The roots of the sprouting cuttings will provide stream bank stability and the living fence will filter pollutants and sediment from the water.
ADDITIONAL BENEFITS: Plants protect stream bank from erosion POTENTIAL TREATMENT AREAS: Stream Banks ALTERNATIVE MANAGEMENT MEASURES: Brush Mattress Brush Revetment Filter Strip Mulching Silt Fence Seeding
LOAD REDUCTION MECHANISM: Organics/Nutrients Management- Willow fence filters surface water runoff before it enters the stream. Sediment Reduction- Stream banks are stabilized by the dense matrix of roots. Salinity Reduction- Plants take up salts from the water.
PERMITTING REQUIREMENTS: As required under Sections 404 and 401 of the Clean Water Act.
LAND USE CLASSIFICATION: Agricultural and grazing lands where nutrients and organic materials may be carried into adjacent streams.
Contact county regional flood control district.
Urban areas where organic pollutants may be released and where impervious surfaces increase runoff.
Arid Southwest BMP
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Brush Trench POLLUTANTS ADDRESSED: Sediments, Nutrients and Organics, Heavy Metals
Level 300: MODERATE ENGINEERING LOAD REDUCTION POTENTIAL: LOW
MEDIUM
PLANNING AND IMPLEMENTATION:
HIGH
1. Select plant species with dense root systems (such as coyote willow - Salix exigua) to bind the soil together securely.
ESTIMATED TIME FOR LOAD REDUCTION: IMMEDIATE
MONTHS2 YEARS
> 2 YEARS
2. Use native species to avoid spreading invasive exotics. Gathering of live branches should not damage other ecosystems.
EXPECTED MAINTENANCE: LOW
MEDIUM
3. Determine the availability of moisture for the cuttings. Either the cuttings will have to reach the capillary fringe of the permanent water table or there will need to be sufficient overland runoff or bank seepage to sustain the willows.
HIGH
ESTIMATED COST: LOW
MEDIUM
HIGH 4. Determine whether toe protection is necessary. In some cases, a brush revetment or fiberschine may be adequate, while other situations may require rock. 5. Give careful attention to both endpoints of the treatment to prevent flows from getting behind the trench. Tying into existing features on site such as trees or rocks or utilizing additional brush or rock are some possible solutions. 6. Do not disturb the site unnecessarily -- the goal is to stabilize the site. The less it is disturbed, the easier it will be to restore. Riparian Planting Zone: Bank Zone.
Arid Southwest BMP
32