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Water Supply

Run off from the school buildings and grounds collects into drains. These drains link into a large storm water drain which empties into Koopoolang Pond. In 2000, cleaning Impurities such as detergents and hydrochloric acid were identified empting via drains into this pond. We have since painted logos on the pavements next to the rains and informed the cleaners. Cleaners now use the alterative sewage system to dispose of wastes. However now that this “sump” pond has become a major fish breeding habitat, we found it necessary to install a filtering system to ensure the water quality is satisfactory

The filter is a cement septic tank (open top) placed below the incoming water from the stormwater drain. It is filled with smashed terracotta tiles, limestone ( to neutralize water) and is covered with special blue aquarium filter foam. All the terracotta and limestone cleans the water being poured into it, filtering out any impurities. This makes the water more alike what would normally be found in the natural environment of the Western Pygmy Perch. The Western Pygmy Perch requires a certain water pH level to be able to live. This filter moderates the water to the Pygmy Perch’s natural requirements



Low levels of water is a problem in summer, especially as there has been an increase in demand for groundwater in the surrounding area. The bottom of the pond has always been at the groundwater level, but this is not deep enough for the fish to survive. The problem was overcome by digging out two pits to fit two large concrete stock water tanks. The shallow cement ponds, 800 cm, have been sunk into the lowest part of Koopoolang Pond. Their placement allow fish to swim into them when water levels fall dramatically. One is covered in a blue weather-proof net that will give anything hiding in there protection from larger outside predators. The other is uncovered so that if they are used, we will be able to compare the two ponds and see if the net is actually effective. A few holes have been drilled through the bottom of the ponds to allow the water table to flow up through, and circulate in, the pond; without these, the ponds would be forced upwards and pop out of the ground by the force of the water table. Since 2005, the ponds have had permanent water.


Stock troughs to be placed below ground level to ensure some water stays during summer


Troughs installed at the bottom of pond, 2005


As the water pours in during the winter months, the soil in front of the drain is eroded. Students constructed a riffle to overcome this problem. The riffle is a rapid setup where basalt rocks are placed down hill of the filter to stop erosion as the newly cleaned water pours out of the filter and into the pond. The riffle stops the rush of water from washing the sand away as it flows into the pond; without it, the filter would slowly be eroded away, along with the banks of the pond. All of the sand being washed away would settle at the bottom of the pond, slowly filling it in, and destroying the habitat that is required for the habitancy of the Western Pygmy Perch. The riffle directs water into the two submerged concrete tanks.


The white water pipe was added in 2005 to keep a flow of bore water during summer. A riffle with basalt rocks was made to reduce erosion as the water flows into the pond.

A pipe from the bore water pump was diverted to top up water to prevent the pond drying up.