Grass Channels Flow Regulation and Overflow
On-line, but consider off-line when inflow is piped
Sized for WQV treatment, larger storms are bypassed
Can receive runoff as sheetflow or concentrated flow
2-year non-erosive velocities
Adequate capacity for 10-year storm with 6” freeboard
Notes:
The grass channel can receive runoff from concentrated sources (pipe outfalls), as well as from lateral sheet flow along the length of the practice. A diversion structure within the drainage network is the preferred method for diverting concentrated flows, prior to entering these treatment practices.
Overflow treatment for grass channels is the same as that for swales, namely, safely conveying the high flow events through the systems at non-erosive velocities.