I have a six acre pond and have two 24” black plastic double wall pipes for my overflow. So far no problem with it handling the overflow ( when it is full). I have a retention pond just on the other side that does catch small fish that I usually trap and return (sometimes) to the main pond. This year we are down about 2’ so far with no rain in sight for months to come. La Ninya is to thank for that. The overflow has worked good for us. They wanted to put in a 24” syphon system out of carbon steel pipe….. too much money and chance of it rotting out., so we went with the flow through of 2 24” pipe