The water enters the system through a 2-inch diameter PVC pipe that is capped at the end and that has a random bunch or holes cut out of its sides (I chopped them out with a miter saw), the whole section covered with a sleeve of plastic mesh 44 inches long that I bought for $25 from Koi Joy. The intake stops well short of the bottom of the pond; this keeps it from getting clogged more than it does, and, in case a leak in the flow develops, prevents the entire pond from being pumped out.