Grassed Waterway
Grassed waterways are used to convey runoff through fields that are subject to gully erosion. This often occurs when a relatively high volume of water drains into and flows through a low point in the field. When gullies form, they increase sediment loading in nearby waterways and streams which can smother benthic communities and harm fish populations. In addition, gullies can cause problems for machinery working the field.
To fix the problem, a channel is shaped or graded to dimensions suitable for the specific site conditions and is established with permanent vegetation. The shape of the channel spreads out the flow of water and the constant cover stabilizes the topsoil. This practice improves water quality running through the field and into adjacent waterways and makes the field easier to work with large equipment.
The criteria used to determine the capacity of a grassed waterway includes the area that drains down to the waterway, the slope of the land, and local rainfall statistics.
