Aquaculture Engineering

Maintenance of ponds - Pond drainage system

Unit 5- Construction of Fish ponds

Maintenance of ponds

Pond drainage system
All ponds need to change some water during fish culture. For this purpose ponds must have suitable independent water outlet with controlled device. The outlet may be open channels, conduits or pipes. The pipes or conduit outlets are suitable for all types of ponds. Asbestos pipes, cement concrete, galvanized Iron pipe, PVC pipes, cast iron pipe are some of different types of pipes used for pond drainage system. The size of the drainage pipe depends on the area of the pond and volume of water in the pond to be drained out. For a pond of 0.1 to 0.2 ha area, an outlet pipe of about 15 cm diameters will be ideal. The pipes of less than 10 cm diameter may be lead to clogging. The outlets or drainage pipes installed at the lowest elevation of bottom of the pond. For larger fish ponds the construction of concrete outlet are highly useful. The outlet pipes should be properly covered with screens to prevent the escape of fish form ponds. For larger ponds pipes are bigger diameter as 20-25 cm are preferable. Drainage pipe should be laid at a slope of 1 in 400. The pipe should be rest on layer of sand hard bed to prevent the pipe against unequal settlement at the base. The percolation of water along sides of drainage pipe can be checked by providing a few concrete collars with pipe which will acts as impervious barriers against the path of flow of seeping water.