One of you expressed an interest when I was describing the project, so I’ll add a bit of detail on initial observations.
The effort appears to be doing exactly what it’s intended to do, the floating cedar leaves doing a better job than the Pinon I used in New Mexico. The fresh cuts on the berms don’t appear to be doing much, but those where the leaves have dropped are blocking with dead leaves, slowing the water enough to cause it to release the silt. And the dead leaves are sealing the parts of the berms where that’s far enough advanced to allow it.
Meanwhile, a rock and brush dam I constructed last week in the arroyo to the east is performing well, also.
The steel grille used to lie on the scoured bottom so’s to allow a truck to cross without blowing a tire on the rough bottom. I stood it up and included it in the dam because earlier efforts have filled the bottom voids with silt enough to provide a comparatively smoother ride across, making the grille redundant as a bottom surface.
The brush and leaves on the right were what was left of the earlier effort, prior to the most recent rainfall.
Depending on the intensity of the coming runoff events, the grille might actually be knocked down and require some remedies if the water level goes high enough to put leverage on the top, but if it doesn’t I believe the bottom will catch enough to provide stability. Those rocks are heavy enough to withstand water to a level of a couple of feet, catching more brush and dropping more silt. Higher than that, they’ll probably wash downstream.
My thought is that the bottom might fill with enough siltation ahead of the dam to need that grille, again, to keep truck tires from going up to the hubs in mud, anyway.