#1, Erosion control on the dam. Emergency spillway would be better with an overflow/drain pipe probably best but hard to do on an existing structure that old.
To add material to the dam I believe the top portion would have to be cut down some and a core trench dug into existing structure. Depending on how far down it needed to go, possibly a flow-through pipe could be engineered at that point.
Any thoughts on how to get the erosion under control? I was thinking I could put an overflow pipe into the channel that has been cut and then cover it with lots of expansive clay to seal it back up.
If I had to I could run the pipe down the backside of the damn into an area where the erosion would be much easier to control and less of a problem.
