Grade stabilization structure at the outlet of a grassed waterway: Full-flow block drop spillway made of wood and cabled concrete. Photo courtesy USDA NRCS.
Grade stabilization structure: Earthen embankment holding water. Photo courtesy Whitewater Watershed Project (MN).
Grade stabilization structure: Water flowing through a full-flow chute spillway made of cabled concrete. Photo courtesy USDA NRCS.
Grade stabilization structure: Recently installed full-flow drop spillway made of metal. Photo courtesy USDA NRCS.
An example of gully erosion. Photo courtesy USDA NRCS.
A gully or grade stabilization structure is an embankment or spillway built across a drainageway to prevent soil erosion. Grade stabilization structures are especially important in areas of Minnesota where sediment loading from gully erosion is a major water quality concern.
Gullies tend to advance upslope at overfalls (small, concentrated waterfalls) below which turbulent water undercuts the head of the gully—a process called head-cutting. Grade stabilization structures control the way water falls to lower elevations, preventing gullies from forming or advancing.
There are many types of grade stabilization structures. Some are full-flow, allowing water to flow freely over a spillway. Others look like a pond and are designed to detain water behind an embankment. Grade stabilization structures are also used to stabilize erosion-prone sites where a tributary or tile drainage outlet enters a channel such as a ditch from the side; the grade stabilization structure slows the flow of water from the higher elevation of the tributary or side-inlet (where water is entering) to the lower elevation of the channel.
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Guidance from USDA's Natural Resources Conservation Service (NRCS)
See contacts for specific programs that fund this practice in the side-by-side payment comparison or contact your local Soil and Water Conservation District
Minnesota Department of Agriculture (MDA), 625 Robert Street N, St. Paul, MN 55155-2538, email@example.com