Alice Springs town basin, review 2003
Read, R. E.
E-Publications; E-Books; PublicationNT; Report ; no. 42/2003
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Department of Infrastructure, Planning and Environment
Report ; no. 42/2003
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7.3 Management The total of licensed allocations for the Town Basin is in the desirable range, but it would be better to increase. The ongoing problem is how to get actual extraction up to the licensed amount. 7.3.1 Northern Zone Policy should be directed at raising extraction to 350 ML/year. Most of this could be withdrawn at less than 800 mg/L. PWC will need to abandon RN 6782 and replace it with a bore in a better location. 7.3.2 Southern Zone Policy should be directed at raising extraction to 900 ML/year. If schemes to remove saline water from parts of the basin, such as that discussed in Figure 31 , are implemented this pumping could be additional to the 900 ML/year for a limited number of years. The major limitation on water use in this area is salinity. Most of this water could be extracted at under 1 500 mg/L, but some will be above this. Some water could be blended with Roe Creek water to produce a mix suitable for irrigation. With better management of the basin average salinity might be reduced to 1000 mg/L. It is no longer necessary to maintain an outflow from the Town Basin into the Farm Basin. Reduction of the saline outflow at Heavitree Gap by pumping upstream would be beneficial to the Inner Farm Basin. 7.3.3 General SKM (2001) recommended a management strategy with five key elements: 1. Extraction of groundwater from the Town Basin aquifer for non-potable purposes, primarily for municipal and domestic irrigation or selected industrial applications. 2. Increasing the level of consumptive use from the Town Basin aquifer, through incentives to existing or new consumers to transfer their demand from Roe Creek water. 3. Reducing discharge from the aquifer by minimising infiltration of groundwater to the sewers. 4. Continuing the program to improve municipal irrigation practices, aiming to minimise the leaching of salts from the unsaturated zone of the soil profile. 5. Work towards maintaining the Town Basin aquifer as a potable water supply by implementing a stringent pollution control and mitigation plan for the aquifer and adjacent weathered bedrock areas. Points 1 and 2 are valid. Point 3 is doubtful. Decisions on the benefits of sewer re-lining are a matter for PWC to consider for its own operations. (Note that a program of sewer re-lining was completed while this report was in progress). Point 4 is important. Point 5 is correct. The Town Basin should be maintained as potable or near-potable for emergency use. It is a valuable renewable resource of water increasingly cheaper to produce than Roe Creek borefield water. 7.4 Licenses All license-holders should be required to submit samples from each bore every six months. A conductivity measurement on these would be adequate. 64