Domestic bore owners' assistance required
Released 21 Nov 2008
The Department of Water is urging private domestic bore owners to assist with its annual groundwater sampling program being conducted in Exmouth this month.
About 80 groundwater licence holders in Exmouth and surrounds were recently sent sampling bottles, and they are being encouraged to take the water samples as directed, and to hand them to the Shire of Exmouth for collection.
The department's Gascoyne District Manager Katrina Burton said all private domestic bores were regularly sampled as part of the management of the Cape Range aquifer.
"Exmouth is one of only two areas in the State where domestic bores are licensed," Ms Burton said.
"This is due to fragility of the aquifer and need for careful management. The Cape Range aquifer is a thin lens of fresh water in delicate balance with the underlying saline water. This fresh water lens is susceptible to over- pumping and requires regular monitoring to detect water quality changes in the aquifer.
"The recommended management strategy is for domestic bores to be fitted with very low yielding pumps (e.g. 20 litres per minute) and intakes set within two to three metres of the water surface.
"This means that better water quality is obtained by slowly pumping into a storage tank and then irrigating from the tank. Sampling undertaken during the surveys has confirmed that bore owners using this procedure have the best quality water - that is the lowest salinity."
Ms Burton said outcomes of the sampling program had indicated that the salinity of the aquifers had remained similar or improved throughout most the town in recent times.
"But ongoing monitoring is important to see whether these bores continue to improve, stabilise or decrease in salinity again," she said.
"Past salinity problems have occurred in the town of Exmouth and a return to these problems would be detrimental to everyone. As a result, all water users are encouraged to regularly monitor salinity levels. Samples can be analysed by Department of Water staff for free at any time - or for a small cost you can buy your own hand held salinity meters. The Shire of Exmouth also has the facility to sample the salinity of the bore water."
Meanwhile, Ms Burton said regular monitoring of the aquifer also provided information to assist in the conservation of stygofauna - animals that live permanently underground in water.
These animals are found in the Exmouth aquifer and are an important part of the area's biodiversity.
"They live in a range of groundwater habitats - from tiny spaces between sand grains to pools and streams in caves and the aquifers themselves.
"Threats to these animals include changes in water quality and levels, contamination of groundwater, removal of groundwater, and compaction of soils.
"Our department is also promoting efficient water usage for licensed bore owners, including adhering to watering outside the hours of 9.00am to 6.00pm. This minimises water wastage due to evaporation and high winds during the day and reduces the volume of bore water required for watering of gardens.
The Department of Water is planning to review the Exmouth Groundwater Subarea Groundwater Allocation Plan in 2008-2009.
Further information will be provided in the near future.
Contact: Dianne Dixon
Phone: (08) 6364 6983 / 0419 910 847