I can only speak in general measurements as this problem was just found. Here goes: I just returned from a 2 week vacation to find my pond water level down about a foot. Have looked at the drain and no water is coming through it. I had noticed what I thought was a new spring about 100 yards below the dam about a month ago, but didn't put this together with the pond as it seemed too far away from the dam. Yesterday I walked below the dam and the ground for about 100 feet wide and 50 feet deep was soggy to the point I could stick a metal rod in about 36 inches and it came out with water dripping from it. I had an excavating contractor who was working on building my house( which, by the way is SUPPOSED to overlook my pond) and he feels there is a leak in the dam. He suggests either draining the pond and repairing the dam, or going on the downstream side of the dam, digging down several feet, making the trench about 10 feet wide, then compacting clay-chert soil and essentially building a new dam below the existing one. At the same time, widening the downstream side of the existing dam to get a better ratio. ( he says the dam was built with a 1:1 ratio on bout the water side and the other, and should be a 3:1 ratio. Anyone have opinions on this technique? He is a fine man, a very good excavator, but honestly is not really familiar with how to do this.
