§ 7.3.10.1. Velocity Controls

Energy dissipation at the outlet may be required to prevent erosion of the channel bottom and banks. The use of baffle blocks, USBR Type VI impact basin, Contra Costa Basin, rock riprap basin, and rock riprap aprons may be used to reduce the velocity of the discharge from the storm drain conduit. See Chapter 10.4.3 for use of different energy dissipators.

The velocity at the end of the outlet structure should be a maximum of six (6) ft/sec. Sandy soils may require a discharge velocity less than six (6) ft/sec. The design engineer should be aware of the types of soils at the outfall location and design accordingly.