There are cameras that could go up your drain to check walls of pipe. I know the cities have them for sewers. Is there some kind of balloon type plug you could shove up the pipe and then inflate? I have seen some for smaller pipes.

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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