The spillway was poured in sections but it was not a lapped pour. In effect it was just big sections of concrete slabs. It it had of been a lapped structure the water going down the spillway could not have undermined the sections of concrete, engineering 101 and also aerodynamics which is fluid flow dynamics. The real hell of it is to make it a lapped spillway would have added minimal costs to the project.
The emergency spillway was a crime of engineering. They built it on unconsolidated ground. This was even a greater crime than the poorly designed spillway. In short order the water going over the emergency spillway started washing out the unconsolidated ground. If this had of continued it would have taken out the adjacent spillway and they would have lost the entire lake quickly and a catastrophic down stream flood would have occurred.
That is why they reopened the damaged spillway despite the damage to it. They damn near lost the lake.
It would be very interesting to see the original engineering proposals for the damn. Were the original proposals changed or was the engineering just piss poor.
“It would be very interesting to see the original engineering proposals for the damn”
again tons of great info in the main thread.....
+Image [1] Original Design proposed to the public for funding - a combined high capacity spillway - Artist’s concept painting.
+Image [2] Original Spillway design with Combined Flood structure - 620,000 cfs total capacity (370,000 cfs main flow + 250,000 cfs emergency flow).
+Image [3] Original Spillway model testing reveals “Fins”, “Standing Waves”, and “monster splashing” (up to 100+ ft re: model scale) @ 620,000 cfs total capacity (370,000 cfs main flow + 250,000 cfs emergency flow).
+Image [4] 3rd round of “fixes” in model testing still reveals challenges @ 620,000 cfs total capacity (370,000 cfs main flow + 250,000 cfs emergency flow).
+Image [5] California Department of Water Resources steps in and makes a “command decision” (”political engineering”) when faced with this design crisis challenge.
+Image [6] Failure is introduced from the “a political engineering decision” with flawed rationale/justification (excludes full scrutiny in engineering thoroughness).
http://www.freerepublic.com/focus/f-news/3524221/posts?page=2596#2596