Grassed waterways are shaped constructed channels that are seeded to grass or other suitable vegetation to convey water to a stable outlet at a non-erosive velocity.
A structure is often installed at the base of the waterway to stabilize the waterway and prevent a new gully from forming.
How it helps
Grass cover protects the waterway from gully erosion and traps sediment in runoff water.
Vegetation can filter and absorb some of the chemicals and nutrients in runoff water.
Vegetation provides cover for small birds and animals.
Planning ahead
Is major land re-shaping needed?
Is there a proper outlet for surface runoff at the bottom of the waterway?
Are soil conservation measures installed to minimize siltation?
Will tile drainage be necessary to establish vegetation in the waterway?
Tech Notes
Shape a waterway so the depth halfway to the center is 3/4 of the depth at the center. For example, if the center depth is 1 ft., depth halfway to center is .75 ft.
The final graded waterway surface to be seeded should be reasonably smooth, free of rills and gullies, and has the designed cross section.
Silt fence fabric checks may be needed after grading and smoothing to reduce potential for gully erosion until seeding is established.
A firm seedbed increases the chance of a good grass stand. A roller or cultipacker may be needed to get a firm seedbed.
Apply fertilizer and seeding at rates recommended by NRCS.
Maintenance
Lift implements out of the ground and shut off spray equipment when crossing the waterway.
Inspect after heavy rains. Fill, compact, and re-seed areas damaged by the rain.
Don’t use the waterway as a roadway.
Avoid planting along the waterway. This prevents a new gully forming on the outside edges of the waterway.
Fertilize as needed.
Mow periodically, but wait until after Aug. 1 to benefit wildlife nesting.
What it is