Rusto,

Given the watershed you don't have to have a conduit to prevent overflow of emergency spillway provided the spillway resists erosion. So I like your idea of something concrete or a combination of rock and concrete at the spillway sufficient to prevent erosion and carry water away from the dam. Forcing overflow across such a surface allows you maximize volume and surface area.

I wouldn't think it would take a whole lot of concrete to do that and it could be patched as needed with hand mixed slurry from time to time.

Last edited by jpsdad; 03/15/21 02:30 PM.
It isn't what we don't know that gives us trouble, it's what we know that ain't so - Will Rogers