Difference between revisions of "Check dams"
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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 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. | ||
| − | {{plainlist|1= | + | {{plainlist|1=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. |
| − | + | *are used, up to 0.6 m in height; the maximum design depth of ponded water must be ≤ 0.6 m. | |
| − | *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. | + | *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|turf reinforcement]]}} | ||
| + | |||
==Sizing== | ==Sizing== | ||
{{:Check dams: Sizing}} | {{:Check dams: Sizing}} | ||
Revision as of 18:14, 27 September 2017
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.
- are used, up to 0.6 m in height; the maximum design depth of ponded water must 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