We just renovated a 6.4 acre lake. We removed 75% of silt and dug out water line to an average depth of 5 ft with 3 to 1 slopes. We used that dirt to raise dam 2 feet and the backslope from 1 to 1 to a 4 to 1 slope. Renovating a lake of this size can be very costly either way you do it. For every foot you add to the dam the yardage amount goes up approximately 18%. Meaning if you have a 20,000 cubic yard dam and add a foot that would be an additional 3,600 yards. The dam that we currently added onto was all done from the back due to some water still being left in the lake. We stripped all topsoil core into top of dam as well along the original backslope that we added to. Cored about 4 feet deep with trackhoe. The is 40 years old.
