General Measures for Sediment Control Silt Fences Silt fences are made of geo-textile filter cloth or similar fine woven mesh. If correctly installed they can be used to trap sediment run-off, for example, around a wetland or a stream that does not have sufficient riparian vegetation to naturally filter out sediment run-off. 2 metres 0.6 metres of geotextile Groundlevel 0.2 metres below surface Ground level Sediment Retention Ponds Sediment retention ponds can be used to trap coarse sediments from larger areas of bare earthworks such as super skids beside rivers or log marshalling areas at barge sites. This will minimise sediment discharging directly into significant waterways and the Marlborough Sounds. The main principle is to have the points of entry and exit for stormwater as far apart as possible to allow the water to slow down and coarse sediments to drop out. Inowing turbid water S Stabilising mat Clean water 18 Sediment Filtered runoff 2 metres y a w l l i p