Rational runoff coefficient

[bdruehl]

What runoff coefficient is appropriate for a gravel driveway? I was going to use 0.5. I am using 0.9 for the concrete portion of the driveway.
Thank you,
Brett

 

[dpa]

I am using 0.7 on a current project. That is the upper end of the range which according to a paper published by ADS is from 0.35 to 0.70. I like to worst case it.

Hope this helps
DPA

 

[gbam]

It really depends on the depth of the gravel d/w and the underlying soils.

 

[bdruehl]

Thank you! I could not find any published ranges for gravel. We did not perc test this lot so I too will use 0.7.