estimated secure yield and water demand in millions of litres per year. The ‘steps’ in the blue secure yield line show the increases in secure yield when each storage dam is implemented.
250
ML/year
200
150
100 Final Demand 75% Demand in Restrictions Final Demand Achievable Restriction in Drought (140 L/p/d) TOTAL Secure Yield
50
2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045
0
F IGURE 23 – SECURE YIELD FOR THE BULAHDELAH WATER SUPPLY SCHEME
Gloucester We are planning for additional storage at Gloucester with a 50ML sedimentation lagoon at the water treatment plant in the next few years and then 250ML of off-stream storage in approximately 2037. The main purpose of the sedimentation lagoon will be to improve water quality; however it will have the added benefit of increasing secure yield. TABLE 7 – GLOUCESTER WATER SUPPLY SCHEME Current situation
Raw water is sourced from the Barrington River. The existing secure yield is 576 ML/year and this is based solely on the volume in MidCoast Water’s extraction licence. However, this secure yield relies on the ‘run of the river’ and there is only approximately four days storage in the existing reservoirs. There is a risk of not being able to supply water during a drought period.
Description of solution
Additional 300 ML of storage in total
Towns supplied
Gloucester and Barrington
Potential additional yield per year
Sedimentation lagoon will add almost 200ML/year to secure yield and 250ML off-stream storage will add over 300 ML/year
IWCM Strategy 2015
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