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The base of the dam is earth/rock embankment.
If the spillway fails, the dam likely fails.
It retains sufficient water to inundate the densely populated portion of the Sacramento Valley.
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the dam does not appear to be in danger, thank god as it hold back 3.5 million acre feet or more... literally a cubic mile of water.
The emergency spillway is now reported to be in danger. that is may not damage the main dam, but it in itself is holding back a half million acre feet....