minimum slope on dirt swale

[roberttx]

Hi,
I am designing a rural street and am having problems giving proper exit to water. What would you recommend for "absoulte minimum" slope for v-ditch dirt swale. The swale measures 12' wide, 8% each side.
Thanks,
Roberttx

 

[civilperson]

Water will flow in a flat bottom ditch, (if you can live with the occasional puddles). No slope is required, 0.5% is visually better after a rain due to fewer puddles.

 

[roberttx]

Thanks, civilperson!

 

[msquared48]

Yep - it's called the backwater effect that essentially establishes a head on the system, allowing the water to flow.

Mike McCann
MMC Engineering