Lee, sorry to hear about your problems but with the info that you have provided me it will be hard to give you an exact reason so I'll just give you some of the reasons that it could be.The first thing that I would look for if I was there would be if there is any trees like willows or cottonwood they can really drop the water levels.Check the surrounding area to see if you have any new found springs or old ones that have increased their flow rates.Look behind your dam not just in the dam area itself but on back as far as 500'you could have missed the clue that would be the tell tell sign.These are just a few hints to look for without going into soil aspects that will probably be next.Hope this helps. DOC
