THanks Tim. After many weeks of studying the site, consulting with people experienced in these things, allowing the lake to seep down naturally till it slowed down, consulting aerial photographs, old construction pictures, and then draining it another 5 feet, we began work today. It will be months before I can tell you well this is going to work, but at least we're trying something different.
We can't detect any reasonable evidence of a seeping levee. It's all bone try and has been. We calculated that the lake was seeping about 30,000 gallons of water a day, maybe more, maybe a bit less. There is just no evidence of that amount of water getting through the levee. If 30,000 gallons was going through it would have blown a hole in the levee long ago. Water is not surfacing anywhere downstream of the levee either. None of the pasture is wet or mirey for a half a mile or more till the creek leaves my property.
The contractor has fixed leaky lakes before but does not claim to be an expert in this speciality. Still, he felt we should start digging near the emergency spillway and dig a trench for a good ways to see what was down there. He has a trackhoe that will dig probably 15-20 feet deep and we went about 15 feet, using a bucket 4 feet wide. He may have been right. Just under the topsoil layer about a foot or so down we hit good hard red clay that was almost like concrete in places....then a huge sand pocket. It was about 4-5 feet in depth and about 30 feet long. Just pure sand. Then we hit red clay again. Above the water line was all red clay. We then took the backhoe and raked tons of that hard red clay and had a big John Deere with a 17 yard dirt pan and also a bulldozer and backfilled the trench. The trench was about 100 feet long, about 15 feet deep, and 4-8 feet wide depending if we doulbe dug it wider where the sand was. We also had a bulldozer and backfilled all of this, then kept scraping good red clay from above the water line and plated over the whole thing about 2 feet deep. We only hit that one sand pocket, but it was a doozy. He said that no doubt a sand pocket that size could suck out 30,000 gallons of water a day.
We are going to plate over part of the area that will be on the bank side of a cove, even down where the water will be 4-6 feet deep. Tomorrow we also plan to move directly across the cove to the area I hit sand with a probe and see what's down there.
That's the latest upsdate. I should know my noon tomorrow if there are any other big sand pockets to core and pack. I know that liners and bentonite and pond seal are excellent for a lot of things. This project has gotten way beyond the economic feasibility of any of that now. He brought some big equipment and we're moving an incredible amount of dirt and covering a lot of ground (literally) in applications that just would not be very practical for any method other than what we are doing.
I'll keep you posted. And thanks for all the suggestions and encouragement.
BillLake
