How to Stabilize Wash Crossing on Private Road

[Mies]

I’m a member of a nonprofit road maintenance group for our community. We are maybe 20 homes with one road this being our only access..We have a wash with a concrete section. Previously, we lost the whole thing in a 10 year flood. To mitigate this we put in a stem wall for the new one about five years ago. Since that time it has slowly become eroded exposing the stem wall. The question I have is this enough here to protect from another flood. Typically when we have a bad flood the concrete section is ~10 feet under very fast moving water.

Approximate dimensions. The concrete drive itself is 80’x25’x2’, stem wall ~60’x6’x2’ wash width ~50’

Things suggested - put in interlocking rip wrap up against the stem wall on top of geotextile fabric with a footing down river. We do have a line on some free cement barriers which we could use to reinforce the wall. Any advice or insight would be greatly welcomed.

 

[swazimatt]

large riprap (median size (D50) being the ones shown on the left of the second photo - then up to 1.7x larger and down to about 0.4x that size to get good interlock )
bring it up to ford height and taper it down as gradually as you can afford.
You could possibly forgo the geotextile if cost is an issue

If you want to use the barriers i would put them under the riprap to take up volume. They are bulky and i think they will cause eddies etc if in direct flow and you want to have uniform flow across everything