In our efforts to be good ecological folk we use a natural spring filled pond to collect water to use to irrigate the garden and the veggies. The pond, or muddy, frog and crab infested swampy hole is halfway up the hillside and has about 200m of pipe to carry the water down to the garden. The pond end of the pipe is a right angled piece with a 2cm opening that is as close to the bottom of the pond as we can get it without it sucking up mud.
However, over time the pond fill sup with dead leaves that slowly rot away and drop to the pond floor and yes you have guessed it, eventually they get sucked into the pipe and bung it all up so we have to drain the pond, clear it up and then unclog the pipe.
In the photo you can see Nuch trying not to fall in as she rakes the leaves from the bottom of the pond and also the end of the pipe (with the right angle turned up to stop it sucking up the mud.We came back a few hours later and the pond was completely filled again.