Pit makes a splash

The recent downpours in coastal Sydney have not all disappeared down the drains. About eight Olympic swimming pools of water have been collected in UNSW's percolation pit - most of which has been returned to groundwater supplies.

Percolation pit 1

The recent downpours in coastal Sydney have not all disappeared down the drains. About eight Olympic swimming pools of water have been collected in UNSW's percolation pit - most of which has been returned to groundwater supplies.

The percolation pit, installed last year underneath Kensington Campus's Village Green, drains the storm water from 70 percent of the campus into the Botany aquifer, which lies beneath the University.

As well as replenishing the aquifer, which is used as an additional water supply by local residents and industry, the pit takes some pressure off Kensington's storm water pipes by channeling the water into the aquifer rather than the sewage system.

Environment manager Paul Osmond said about one megalitre an hour infiltrates the pit. With the intensity of recent rains, some will have been lost into the Randwick City Council stormwater system. But the overall result, he says, is highly pleasing.