Hydraulic Conductivity for Larger Stone 1

[jrl802]

We are looking to execute an "emergency" repair where we utilize "baby" A stone to build a dike that can retain (some) water or at least reduce flow across a flood plain until it overtops. The structure is basically a dike. The referenced material is what is most readily available on site. Top size is about 2,500 lbs. 10% fraction is about 1 to 5 lbs so basically cobbles. I told our river engineers that the dike would leak like a sieve. They want to know ballpark how much. The structure will vary in height from 3 to 6 ft tall. I've seen published values of 100 cm/s for clean gravels. I think this would be on the low end. Any other thoughts?

 

[GeoEnvGuy]

Recommend looking up Frizell Simplified design guidelines for rip rap subjected to overtopping flow or erosion design manuals for some guidance. To make it hold water somewhat back you will need typically a silty sand with at least 15% fines content.