Cross - what I have read is that core samples showed that bedrock begins 30' below the emergency spillway. It is expected that erosion would undercut the concrete apron to that point in short order, but then stop or be significantly slowed.
I should have worded it differently. Just saying that the auxiliary is connected to the dam, which some said it isn't. Sure it's not part of the concrete dam, but an earthen dam is still a dam.
