Line 1:
Line 1:
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:
−
*Check dams usually consist of crushed rock gabions, or pre-treated timber up to 0.6 m in height.
+
*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.
−
*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. See: Sizing
+
*designed for higher flow velocities should have spillways incorporated into their profile, to direct water to the centre of the swale.
−
*Where check dams are used, the maximum design depth of ponded water must be 0.5 m.}}
+
*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}}