It's just a screenshot so bear with me. And this was taken when the lake was lower. You can see the dam. To the left, a channel and the spillway gates. The channel is dry in this photo.
There is no concrete spillway like Oroville, just dirt and rock. The Don Pedro spillway was constructed a distance from the dam and at a 90 degree angle away. For this reason, erision of the dam is not likely.
The released water will wash out the road below and follow a natural ravine down to the river. This ravine was scrubbed to bedrock back in 1997 when the gates were first opened and little in the way of soil or vegetation exists.
Here's the area below the spillway after the 97 release.
