Erosion control is the practice of preventing or controlling wind or water erosion in agriculture, land development and construction. This usually involves the creation of some sort of physical barrier, such as vegetation or rock, to absorb some of the energy of the wind or water that is causing the erosion. Effective erosion controls are important techniques in preventing water pollution and soil loss. They are often implemented in conjunction with sediment controls such as sediment basins and silt fences.
A silt fence is a temporary sediment control device used on construction sites to protect water quality in nearby streams, rivers, lakes and bays. A typical fence consists of a piece of synthetic filter fabric (also called a geotextile) stretched between a series of wooden or metal stakes. The stakes are installed on the downhill side of the fence, and the bottom edge of the fabric is trenched in the soil and backfilled on the uphill side. The fence is installed on a site before soil disturbance (earth moving) begins, down-slope from the disturbance area.
By reducing soil erosion, cover crops often also reduce both the rate and quantity of water that drains off the field, that would normally pose environmental risks to waterways and ecosystems downstream. Cover crop biomass acts as a physical barrier between rainfall and the soil surface, allowing raindrops to steadily trickle down through the soil profile. Also, as stated above, cover crop root growth results in the formation of soil pores, which in addition to enhancing soil macrofauna habitat provides pathways for water to filter through the soil profile rather than draining off the field as surface flow. With increased water infiltration, the potential for soil water storage and the recharging of aquifers can be improved. Just before cover crops are killed (by such practices including mowing, tilling, discing, rolling, herbicide application) they contain a large amount of moisture. When the cover crop is incorporated into the soil, or left on the soil surface, it often increases soil moisture. In agroecosystems where water for crop production is in short supply, cover crops can be used as a mulch to conserve water by shading and cooling the soil surface. This reduces evaporation of soil moisture. In other situations farmers try to dry the soil out as quickly as possible going into the planting season. Here prolonged soil moisture conservation can be problematic. While cover crops can help to conserve water, in temperate regions (particularly in years with below average precipitation) they can draw down soil water supply in the spring, particularly if climatic growing conditions are good. In these cases, just before crop planting, farmers often face a tradeoff between the benefits of increased cover crop growth and the drawbacks of reduced soil moisture for cash crop production that season.
Hydroseeding (or hydraulic mulch seeding, hydro-mulching, hydraseeding) is a planting process which utilizes a slurry of seed and mulch. The slurry is transported in a tank, either truck or trailer mounted and sprayed over prepared ground in a uniform layer. Hydroseeding is an alternative to the traditional process of broadcasting or sowing dry seed. It promotes quick germination and inhibits soil erosion.
The mulch in the hydroseed mixture helps maintain the moisture level of the seed and seedlings. The slurry often has other ingredients including fertilizer, tackifying agents, green dye and other additives.
A temporary dam constructed across a swale or drainage ditch to reduce the velocity of water flowing in the channel. Ditch checks can be constructed out of stone, a double row of straw bales or from engineered products. The purpose of this practice is to reduce flow velocity and to pond water, thereby reducing active channel erosion and promoting settling of suspended solids behind the ditch check.