Kennylee

If the slump is caused by water leaking around the pipe you will have to dig the pipe out and re set it. that is not really as big a job as it sounds but the important part will be the installation. The dirt will need to be compacted from under the pipe to the top of the dam.

First measure the elevations to make sure it is as bad as you think. I have a hard time seeing a dam settle as much as you are thinking and it not breaching. Keep us posted

Otto