The air bubbles that are coming out of the water push the water up over the surface 1 to 2 inches. It is there for a long time so as not to form ice. Does your springs create bubbles like that or are they just an opening created by the warmer water coming to the surface. The small hole do look like your drain holes.

61 acre water shed lake. bass, channel cat, black crappie, wiper, walleye, redear sunfish, blue catfish and bluegill. To many bullhead and common carp
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