A small vertical wall constructed from wire fencing and rock or soil, placed across a drainage way, swale or road ditch to reduce erosion and collect sediment.
When is a Post & Wire Check Dam Used?
Check Dams are used where runoff is concentrated in a drainage way, swale, or road ditch that has lost all its natural protection due to the fire, or will receive increased flow rates as a result of fire in the contributing drainage area. The dams will reduce erosion and trap sediment generated from adjacent areas or the ditch itself. Post & Wire Check Dams should be limited to use in open channels that drain 50 acres or less.
How is the Post & Wire Check Dam Installed?
Referring to the illustration, the maximum height of the wall should not exceed 3.0 feet. The top of the wall should be at least 1 foot below the top of the channel or swale. The width of the wall should be a minimum of 3 feet. The dams should be spaced uniformly down the drainage way as follows:
Rock Check Dam Spacing in Feet
1 ft. Dam Height
2 ft. Dam Height
3 ft. Dam Height
2 - 5
5 - 10
10 - 15
15 - 20
The wall at the center of the channel should be at least 1.5 feet lower than the sides. The ends of the wall should be keyed into the channel sides a minimum of 4 feet. If the wall is filled with rock, it should be of sufficient size and quality to meet Colorado Department of Transportation specifications for 6 inch D50 Rock Riprap. If the wall is filled with soil, it should be lined with a geotextile before placing the backfill.
What Maintenance is Required?
The Rock Check Dam should be inspected after every rainfall event, and repaired as necessary.