Grassed waterways are broad, shallow channels designed to move surface water across farmland without causing soil erosion. The vegetative cover in the waterway slows the water flow and protects the channel surface from rill and gully erosion. Waterways are often constructed in natural depressions where the water collects and flows to an outlet.
A grassed waterway should be deep and wide enough to carry the peak runoff from large storms. NRCS can help you determine the correct size for your grassed waterway. If properly sized and constructed, grassed waterways will safely transport water down slopes and prevent erosion. Waterways may also be used to provide outlet channels for terrace systems, contour strip cropping operations and diversion channels.
Grassed waterways are a good solution for controlling ephemeral gullies, which is required by conservation compliance provisions. Inspect grassed waterways annually or after unusually large storms. Promptly perform needed maintenance to prevent costly damage to the waterway.
Proper shaping, seeding and grass establishment are the keys to installing a successful grassed waterway. After reviewing your waterway site, NRCS can provide information on shaping the grassed waterway as well as provide seeding recommendations.
Seeding early enough to give the grass time to establish before heavy rains is key to establishing effective grassed waterways. To protect the new waterway from erosive rains during grass establishment, NRCS recommends using fabric checks. Without these, another ditch can form and wash out the grass seed during heavy rains.
Grassed Waterway Maintenance Tips
Lift implements out of the ground before crossing the waterway.
If possible, bring row crop patterns into the waterway nearly on the contour, or use it as the turn area. Don't plant end rows along the side of the waterway.
Plant good quality, NRCS-approved seed and fertilize periodically.
Inspect the area frequently for eroding areas and places needing reseeding. Repair minor rills or gullies by reshaping and reseeding.
Maintain the width of the grass area when tilling and planting adjacent fields.
Avoid spraying herbicides in the waterway.
Avoid driving up and down grassed waterways, especially during wet conditions. The ruts caused by tire tracks can lead to gullies.
Maintain outlets to prevent gullies from forming. This may include reshaping and reseeding the outlet, or repairing components of structural outlets.