I am not going to pretend to comprehend how they get in there. I do know if you want to catch bullheads the best ponds were ponds that had very recently been cleaned out. I also know of ponds that went been dry in the 80s and didn�t fill until the late 90s. My father claimed before they went dry they were awesome bass ponds. When they filled they were never stocked. However when a buddy of mine finally fished them the amount of 5 lbs+ bass that came out of the pair was amazing. They were at the top of the watershed with no nearby ponds out in the middle of the flint Hills.