It's better not to have the thru-dam pipe filled with water all the time. Any small leak in the pipe will create problems with the dam. It's better (and more commom) to have the riser on the pond side of the dam, and when the water drops below the top of the riser, the pipe stays dry inside.

Make sure you compact the soil properly around the pipe, and put in a couple of anti-seep collars.

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3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).