Assessing the ecological value of NSW Rivers
High Ecological Value Aquatic Ecosystems
Ecological value is how we perceive the importance of an ecosystem. We assess the ecological value of rivers using the High Ecological Value Aquatic Ecosystems (HEVAE), which is a national framework. We assign a value to a length of river to determine the importance of each river relative to others. Identifying rivers of high importance or high value allows for their protection and enhancement. These values help develop and remake water sharing rules in NSW rivers.
We use the HEVAE framework for inland freshwater rivers and coastal rivers above the tidal limit. Inland rivers use four of the five HEVAE criteria including diversity, distinctiveness, naturalness and vital habitat. For coastal rivers, we only have suitable information for three of the criteria; diversity, distinctiveness and naturalness. Improvements to information for all rivers will enable all five criteria from the national framework to be included in future work. Download Figure 1, a simple diagram explaining the criteria and HEVAE framework.
We have completed mapping the value of rivers for all NSW inland rivers. Work on the coastal rivers is almost complete. A detailed technical report on how the HEVAE framework has been applied in NSW is available.
The HEVAE framework is also included in our River Condition Index work, a reporting tool for assessing the change in river condition over time. We also use the HEVAE in our Water Sharing Plan risk assessments to describe the instream values (called Consequence in this process) that are considered may be at risk from surface water extraction.