Determining strategies to protect or restore ﬂow regimes to achieve ecological outcomes is a focus of water policy and legislation in many parts of the world. A team from Queensland DNRM has developed a risk-based ecohydrological approach that links ecosystem values to desired ecological outcomes. This allows the relative risk from different ﬂow management scenarios to be evaluated at relevant spatial-scales and a robust and useful foundation upon which to build the information needed to support water planning decisions. A case study using the eastern long-necked turtle is presented, with input from IAE staff and former students.
For several decades there has been recognition that water resource development alters river ﬂow regimes and impacts ecosystem values. Determining strategies to protect or restore ﬂow regimes to achieve ecological outcomes is a focus of water policy and legislation in many parts of the world. However, consideration of existing environmental ﬂow assessment approaches for application in Queensland identiﬁed deﬁciencies precluding their adoption. Firstly, in managing ﬂows and using ecosystem condition as an indicator of effectiveness, many approaches ignore the fact that river ecosystems are subjected to threatening processes other than ﬂow regime alteration. Secondly, many focus on providing ﬂows for responses without considering how often they are necessary to sustain ecological values in the long-term. Finally, few consider requirements at spatial-scales relevant to the desired outcomes, with frequent focus on individual places rather than the regions supporting sustainability. Consequently, we developed a risk-based ecohydrological approach that identiﬁes ecosystem values linked to desired ecological outcomes, is sensitive to ﬂow alteration and uses indicators of broader ecosystem requirements. Monitoring and research is undertaken to quantify ﬂow-dependencies and ecological modelling is used to quantify ﬂow-related ecological responses over an historical ﬂow period. The relative risk from different ﬂow management scenarios can be evaluated at relevant spatial-scales. This overcomes the deﬁciencies identiﬁed above and provides a robust and useful foundation upon which to build the information needed to support water planning decisions. Application of the risk assessment approach is illustrated here by two case studies.
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