The Water Resources Act requires that 55% of water that flows through the ACT is not available for consumptive use in the ACT and that water is given to the environment to maintain river systems and associated ecosystems (environmental flows).
Environmental flow requirements apply to all Territory water resources including water in rivers, streams, dams, lakes and groundwater aquifers. Environmental Flow Guidelines are prepared to identify the ecological values to be protected and the measures to be employed to protect them. In the ACT, this is generally by limiting the amount that can be extracted from a waterway in a way that protects flow variability and low flows. The Guidelines recognise the highly connected nature of surface and groundwater and the contribution that groundwater makes to the base flow of stream during drier times. In selected high use catchments the Guidelines specify actual flows that must be maintained in certain conditions as well as their review through an adaptive management regime.
The Guidelines set out the volumes and timings of environmental flows and abstraction limits in streams, rivers, lakes, and aquifers. They were first produced in 1999 and reviewed in 2005-06 and in 2011-12.