New South Wales Consolidated Regulations

WATER SHARING PLAN FOR THE MACQUARIE AND CUDGEGONG REGULATED RIVERS WATER SOURCE 2003 - REG 64

64 Airspace operation rules

(1) Airspace operation of Burrendong Dam shall be undertaken in accordance with the following rules:

(a) when not in flood operation, releases from Burrendong Dam FMZ should be made to provide beneficial flooding for the regulated Macquarie River, the Macquarie Marshes, Marebone floodplain and effluent creeks. The sharing and distribution of FMZ releases should be to:

(i) the Macquarie River and Macquarie Marshes when flows at Warren are less than 4,000 ML/day,

(ii) the Macquarie River and Macquarie Marshes, and Marebone floodplain, then Crooked, Gunningbar and Duck Creeks when flows at Warren are between 4,000 and 12,000 ML/day, and

(iii) the Macquarie River and Macquarie Marshes, and Warren floodplain, then Crooked, Gunningbar, Duck, Ewenmar and Beleringar Creeks when flows at Warren are greater than 12,000 ML/day,

(b) the FMZ operation shall where possible, place emphasis on making controlled releases during the flood event so that the storage does not increase.

Note: This attempts to balance the benefits of providing airspace in Burrendong Dam to mitigate large inflow events with the damages of controlled releases that can extend the duration of flooding on the Warren floodplains.

(c) releases from the FMZ will vary according to the storage level, rate of inflow and the need to maintain airspace to capture likely future storage inflows, and therefore the storage shall be divided into 3 bays,

(d) each bay shall have different maximum rates of releases, and these releases which are above water orders, shall be equal to the inflow up to the maximum combined release, plus downstream tributary flow, and these releases shall be in accordance with the following:

(i) bay 1-Burrendong Dam water storage between 100% and 120%, and releases to a maximum of 5,000 ML/day at Warren, which equates to approximately 5.5 metres at Warren town,

(ii) bay 2-Burrendong Dam water storage between 120% and 130%, and releases to a maximum of 12,000 ML/day at Gin Gin, which equates to approximately 6.5 metres at Warren town, and

(iii) bay 3-Burrendong Dam water storage between 130% and 142%, and releases to a maximum of 18,000 ML/day at Gin Gin, which equates to the minor flood level of 7.5 metres at Warren town,

(e) release rates lower or higher than those indicated in subclause (1) (d) for each FMZ bay may be made if:

(i) the release rate specified in subclause (1) (d) will cause prolonged inundation of the floodplain and result in economic losses to agriculture,

(ii) the release rates specified in subclause (1) (d) will restrict landholder access to their properties for extended periods, or

(iii) the environment and community would benefit from lower or higher rates of release, and

(f) releases from the FMZ can be used to provide access to water under regulated river (high security) access licences, regulated river (general security) access licences and supplementary water access licences, subject to clause 48.