Check dams
Revision as of 18:28, 23 October 2017 by Jenny Hill (talk | contribs)
Check dams are small dams or weirs constructed across a drainage ditch, swale, or channel to lower the speed of concentrated flows for a certain design range of storm events and to promote infiltration.
Check dams:
- may be constructed of any resilient and waterproof material, including: rock gabions, earth berms, coarse aggregate or rip-rap, concrete, metal or pre-treated timber. Rocks used in check dams should have median diameter 25-75 mm.
- for enhanced swales may be up to 0.6 m in height; the maximum design depth of ponded water should be ≤ 0.6 m.
- designed for higher flow velocities should have spillways incorporated into their profile, to direct water to the centre of the swale.
- are usually installed between 10-20 m along the swale. The spacing of dams should not exceed the horizontal distance from the toe of the upstream dam to the same elevation on the downstream dam.
- should have energy dissipation and erosion control measures installed in the 1 - 2 m downstream. Examples include large aggregate or turf reinforcement