Without landscape fabric, I would build it just like a roadbed. Put down a layer of large rocks (#2's) to create a firm base then top with smaller rocks then finally sand.

You have to put something down to prevent the sand from sinking into the clay and disappearing.

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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).