How to Improve Drainage in a Ditch

Ditches Prevent Flooding

Improperly built or maintained drainage ditches can cause severe flooding during the springtime, making road travel hazardous or even impossible. It is best to do preventive maintenance on your drainage ditch in the summer or fall to improve drainage rather than waiting for a problem in the spring.

Things You'll Need

• Shovel
• Hoe
• Backhoe
• Grass seed

Instructions

1. Inspect culverts to make sure they are clean and free of any blocking debris, including mud and muck. Clear the culverts with the shovel, using the hoe to drag sediment closer if needed.

2. Add culverts to help drainage across roads, driveways, and other obstacles.

3. Determine if the ditch fall is angled properly for drainage. The recommended angle is 0.5 degrees downhill. If the ditch is not at this slant you may need to re-grade the longitudinal slope. If the ditch is too steep it can lead to soil loss.

4. Adapt the ditch to a two-stage ditch system. Leaving the bottom of the ditch alone, create a broad, flat shoulder on either side of the central channel either by manually cutting away the top of the ditch with the shovel or using a backhoe. The shoulders, or benches as they are sometimes called, should be wide enough to be mowed easily and sit far enough above the normal water level to remain relatively dry most of the year. Re-seed the disturbed area with grasses to prevent erosion.

Tips & Warnings

• How wide and deep your ditch should be depends on the amount of land it services.

• A surveyor is most qualified to determine the angle of the ditch.

• Check the local regulations regarding changes made to slope or drainage profiles before starting work.

References

• Engineering Department, Wisconsin: Drainage
• The Nature Conservancy: Two-Stage Ditch Design
• Great Lakes Commission: Two-Stage Ditch Design
• U.S. Forest Service: Road Preconstruction Handbook