Appendix 2 – Components of the Base Scenario Build measures Off-stream storages at Bulahdelah, Stroud and Gloucester to improve the secure yield of these water supply schemes The commissioning of the Nabiac Inland Dune Aquifer Water Supply System which will provide an alternate and additional water source for the existing Manning scheme. Replacement of the Gloucester Sewage Treatment Plant Upgrade of the Gloucester Water Treatment Plant Improvements to the Gloucester Water Distribution System Eventual transfer of Old Bar’s treated effluent to Taree, with some to be reused for farm irrigation. This is necessary as the exfiltration basins at Old Bar are under threat of erosion and the alternative effluent management solutions, a new ocean or river release, were deemed unacceptable. Infiltration reduction program to reduce stormwater infiltration into the sewerage systems Non-build measures Demand management measures. MidCoast Water is committed to reducing demand as far as practicable and there are many options available that can help to achieve this.
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Smart meters to help reduce leaks and reduce demand slightly Changes to pricing including tariff pricing Behavioural change programs The targeting of high water users to help them reduce demand Continuation of the smart water rebate scheme including rebates for rainwater tanks. Community education on the efficient use of water and ways to reduce household and business demand.
Leakage management program for the water schemes to reduce the volume of water lost due to leaks. Continuation of existing recycling schemes A reduced level of service (the risk of longer and more frequent water restrictions) during the period up until the long-term water security solution is delivered.
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For the Manning Scheme, this will mean a shortfall in secure yield of approximately 1 GL, once the Nabiac Scheme is commissioned, or 12% of annual demand. The shortfall is the difference between the annual demand and the calculated secure yield. The implications are that, in the worst case scenario such as a severe drought, we would not be able to supply water without ‘breaking’ the 5-10-10 rule. That is, we would need to implement water restrictions for longer than 5% of the time, more often than 10% of years and/or require a reduction in water use greater than 10%. For the Bulahdelah, Stroud and Gloucester schemes, the situation would be similar, in that until off stream storage is constructed, there would be shortfall between secure yield and demand. Contingency plans will be required for emergency situations and these plans will be developed. This may involve planning for a temporary
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