Thank you. Also on page 133 in regards to the ESpill: "In part of the emergency spillway, an additional 10' of excavation was required to reach acceptable foundation rock, resulting in considerable time for excavation and placement of the backfill concrete to subgrade".You've confirmed something that was unclear. The emergency spillway was placed directly on bedrock. No mention of laying wood or anything under the concrete. Rock was obviously cut for the key on its upstream side, but they didn't try to grind the whole surface flat. (The key tool seems to have not cut a "V", but did need a wedge shape on the upstream side, as fill is noted there.) It probably resembles the somewhat smooth surface visible behind the weir. But it's a somewhat bumpy surface, so the concrete fitted itself into whatever shape that was underneath it. By now, the wooden drain locations are probably somewhat larger drains due to rotting of wood.
This doesn't mention any type of anchoring of the Espill, but they worked hard to get down to prime bedrock, which is good. Did they think this massive structure wouldn't need any type of anchoring if they got to such nice bedrock?
Also on page 133 when talking about building the main spillway I thought it was interesting that it sounds like they had a harder time with the outlet gate rock they were working with: "The slopes in the flood control outletgate section proved to be lower quality rock than anticipated. There were several large seams running parallel with the chute. The planned anchor bars were replaced with grouted rock bolts, pigtail anchors, and chain-link surface covering in that area".
I am having a hard time figuring out why the rock at the outlet gate was so different than what they say they worked with to lay the Espill on? It also talks about having to air blast down below the outlet gate to get to foundation rock, but the outlet gate was so different.