Skimmer
TexasPonds.com
Texas' Most Natural-looking Water Features
An awesome invention that substantially reduces pond maintenance, the CleanSweep Skimmer allows the pump to sit inside and skim surface debris from the pond as it operates.  All you need to do is empty the catch bag and periodically rinse the filter pad.  Depending on the amount of surface debris your pond has, you can spend as little as 5 minutes per month emptying your skimmer.  An automatic overflow valve is positioned in the back to route excess rainwater away from the pond.   
The CleanSweep Skimmer is an invention that performs several functions in a low-maintenance pond.  It will be buried in the ground at pond's edge and only the faux-stone lid will be visible.  It looks relatively simple from the outside, but broken down, we can see how the unit works.
Faux-stone lid
Pump
Skimmer Rack
Skimmer Mat
Check Valve
Debris Net
Faceplate and Weir
In addition to skimming surface debris from the pond, the skimmer also protects the pump from clogging by channelling the pond water through two pre-filters before it ever reaches the pump.  There is no chance of a malfuntioning bottom drain emptying your entire pond and leaving your fish stranded with this system.
Pumps from 1500gph to 10,000gph are available and have been designed exclusively for use in a pond skimmer.