SnrubThe Flash board riser thing is spot on(the front side of it), would either need to buy and modify or build my own looks like it would not be to hard to build one. I found Grundulis's setup there on the last page his is nice cause it's at the base of his dam. My pond's I have limited area's to drain them and can only draw them down 2' with gravity no way to do a full draw down except with pumps. Since his is tied in much like any drainage pipe into the bottom of the dam I get how his is compacted and tied in.
The only thing that is confusing to me is how do I tie my idea in to the rest of the dam to prevent leaks. It will not have much pressure on it. I'm thinking I just need to make the face of it wide say 8-10' of concrete about 1' thick on each side of the opening and obviously down to the bottom of the pond that would have about 10-12' of good solid clay behind it.
