I have two 1/4 acre ponds that are currently muddy. When I have pumped a substantial amount of fairly clear creek water into them, the suspended clay flocculates and settles out for a few months. I haven't pumped for nearly a year now, and they are increasingly muddy with suspended clay that doesn't settle in a bucket test.

My question is: What could be in the creek water that causes the ponds to flocculate? The amount of creek water needed to cause it is probably at least 25% of the pond volume.