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Post and Wire Check Dam Fact Sheet

What is a Post & Wire Check Dam?

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

Channel Slope(%)

1 ft. Dam Height

2 ft. Dam Height

3 ft. Dam Height

< 2




2 - 5




5 - 10




10 - 15




15 - 20




> 20

not recommended

not recommended

not recommended

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.

Post & Wire Check Dam Construction Details.