Sedimentation Basin

[zahid106]

I have a phased development with a regional detention basin. The drainage area for regional detention basin is 36 acres. Twenty six acres of the drainage area are developed. we are in the last phase of this project and working on the developing 10 remaining acres. City is requiring a sedimentation basin. we would like to use this regional basin as temporary sedimentation basin. The basin needs to remain operational for developed areas. Any ideas / experience with how to do that.

 

[gbam]

Can you excavate the bottom of the basin to provide dead storage for sediment? Maybe need to talk with owner of the basin.

 

[beej67]

You could retrofit the outlet control of the detention basin to capture sediment pretty easily, but it would impact the detention characteristics of the basin. You'd probably have to go back and check the hydrology to make sure the thing was operating within parameters during construction of your final phase.

If your municipality is allowing you to be creative, you could do what gman suggests and over-excavate the basin with a riprap berm or similar as a control, like a giant forebay. You might even be able to leave it in place after construction to provide additional water quality treatment in the long term. But that kind of BMP might not be 'standard' for your region, so it might require you to do a good job selling it to the municipality before specifying it on the plans.

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