What The Heck Is A WASCOB?
News Feature 3/26/2013
What The Heck Is A WASCOB?
No, it’s not a new USDA “Going Green” initiative for using corn residue. WASCOB stands for Water And Sediment Control Basin, a structural sediment erosion control practice eligible for incentive payment under the USDA-NRCS Environmental Quality Incentive Program (EQIP). More on WASCOB’s later ...
Structural conservation and upland land treatment practices go hand-in-hand when it comes to a comprehensive conservation farm plan. Structural practices are those that control water erosion using engineered solutions. Structural practices are mostly used in areas with steep fields and/or concentrated flow areas that are particularly vulnerable to excessive erosion by runoff. Some of the more common structural practices include:
· Grassed Waterways – This engineering practice involves constructing a vegetated channel that conveys runoff without eroding the underlying soil. The size and shape of a grassed waterway is based on the amount of runoff that the waterway must carry, the slope of proposed waterway, and the underlying soil type.
· Water and Sediment Control Basins (WASCOB) – WASCOBs are a series of small embankments across concentrated flow paths on cropland that store then slowly release runoff through an underground outlet. As sediment laden runoff enters the basin, it is stored and sediment is settled out. The intakes that meter the water out are typically a plastic perforated stand pipe about 4 feet high. The embankments themselves can be designed to be farmed.
· Terraces – Terraces are similar to WASCOB’s except that they are not built across a single water course. A terrace embankment is built to intercept sheet flow across a field. Spacing between terraces is designed such that the sheet flow distance is broken up into non-erosive lengths. Sites that are suitable for terraces usually have long, continuous slopes that do not contain defined concentrated flow channels.
· Grade Stabilization Structures – These types of structures are designed to convey runoff across a steep drop in a non-erosive manner. Typical applications include dropping runoff flows from field level down into a ditch with a pipe or an open rock chute. Larger applications such as controlling the advancement of a large ravine or gully up into a field usually involve long lengths of pipe to convey runoff flows down to a stable outlet.
· Streambank Protection – Streambank protection is used to prevent soil loss caused by a erosive stream flows against a channel’s bottom and banks. Typical applications include rock rip rap and vegetative treatment (bioengineering). As an alternative to completely lining a bank with rock, stream barbs or “J-hooks” may used in certain circumstances.
To ensure a long life for structural practices, landowners are required to install land treatment measures upstream on highly erodible acres. Also, structural practices will play an important role in ensuring a stable soil resource for those acres that may be coming out of Conservation Reserve Program contracts back to cropland status. All these above practices and more are eligible under the EQIP program. Contact your local NRCS office for more information.
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