Dammed up a cove in the upper end, used gabon stone and 3/4 limestone, 45 mil epdm liner on dam attached to 40 mil hdpe lake bottom with bentonite. 10" schedule 40 pvc going thru bottom with kleenout plug on lower end, upper end 10" to 4" reducer tacked in with vaseline, connected to 90 degree elbow, then 4" pvc with strainer upright, so I can turn the 4" vertical pipe down a few degrees to drop water level, or all the way down to empty. After releasing fish back to main lake, the rock structure will be a major structure with a 10" pipe open for fish to use as they wish. This setup will literally give me an opportunity to select which fish go back into main lake before flooding. This material cost several thousand dollars, I did all the geotextile, material construction, lining, etc. I'm justifying the cost spent in saved fish and the rock dam will serve as a permanent fishing structure. And when the lake is dewatered in the future, a matter of when, the system for keeping and discarding is already in place. It covers about 1/3 acre, 3.5' deep at the dam, plenty of cover, and contains aeration.
