Changes

1) PVC filters are used in combination with ground runoff: In general it is best to reduce the speed of the water as much as possible to avoid the pond from filling up with sand and clay – this can already be done by planting grasses and other catchment methods (for methods, see [[Natural ground catchment and Open water reservoir]]); The PVC filter pipe can be between 25 – 100mm and acts as a screen to allow water to infiltrate into the gravel layer (i.e. PVC has horizontal slots cut in the side) - the pipe protrudes just above the base of the pond; A PVC cover piece is fabricated which is closed at the top and flares at the base so that it fits over the protruding pipe – the purpose of the cover is to prevent too many sediments entering the pipe and is removed only 4 hours after rainfall. Once water has infiltrated, the cover is replaced until the next time; Cleaning involves swabbing the inside of the PVC with a cloth.<br>