As another consideration if you raise your dam you will have to strip off the top soil from the front above water level.the top and back just to get good clay to adhere I even try to cut a key way down the middle to prevent any leaks from showing up cause if it leaks between the new and old part you could have some major repair bills.Then adjust your dam to a 4to1 slope and reinstall your top soil and seed as soon as possible to prevent erosion and good luck.DOC

Doc