Stabilize Steep Slopes
Steep slopes that are difficult to manage can be planted with low-maintenance trees, shrubs, and perennials to stabilize the soil and make it more permeable. This helps slow down run-off and prevent erosion and, in addition, decreases maintenance while enhancing aesthetics and habitat. Use of biodegradable erosion netting is recommended during the plant establishment phase. There are many forms of biodegradable erosion fabric, such as mats, netting or blankets. Never leave steep slopes with bare soil exposed.
Check dams are placed perpendicular to the flow of water so that water flows through or over (not around) them, thus slowing down the water and controlling erosion and sedimentation. Check dams may be compost socks, straw wattles or rock weirs.
A compost filter sock check dam is a flexible mesh tube, or tubular ‘sock,’ made of a permeable cloth that is filled with compost and anchored into place. They are available as either a permanent or a biodegradable product and may be vegetated (planted) if desired. Planting trees or shrubs on or by the compost sock will help anchor it as the plant roots grow. An advantage of the compost filter sock is that it filters pollutants and sediment as the water flows through the sock dam.
Straw wattles are similar to compost sock dams in that they are a mesh tube filled with straw but they are not typically planted.
A rock weir is a pile of stones lined up to slow down the flow of water on a hill. An advantage of the rock weir is that it can be a more stable structure, more able to withstand high velocity flow on a steep slope.
Check dams can be back-filled with topsoil and vegetation to form terraces that will stabilize a steep slope, to increase both infiltration and evapotranspiration rates, and to help prevent soil erosion.
If water is coming from a concentrated source (such as from a parking lot stormwater outlet or gutter downspout), a meandering bioswale punctuated by rock weirs will capture the runoff and help to prevent erosion by slowing the flow of water down the hillside.
See Erosion and Sediment Control Resources section.