Introducing the High Ecological Value Aquatic Ecosystem (HEVAE) Instream Value of Freshwater Rivers in NSW

The [NSW riverine High Ecological Value Aquatic Ecosystem (HEVAE) project](https://water.dpie.nsw.gov.au/our-work/science-data-and-modelling/surface-water/monitoring-changes/environmental-value-of-nsw-rivers-hevae) aims to identify and define a range of instream values and levels of importance for freshwater river reaches in NSW. These values will assist in the prioritisation of areas for focused water management, to assist with water sharing between water users and the environment. The water management options include assessment of access and trade rules within Water Sharing Plans (WSPs). The HEVAE product enables NSW DCCEEW Water to better meet water management requirements under the Water Management Act 2000 and Murray-Darling Basin Plan 2012. The [HEVAE Framework](https://www.dcceew.gov.au/water/cewo/monitoring/aquatic-ecosystems-toolkit/module-3-guidelines-identifying-high-ecological-value-aquatic) was developed by the Commonwealth Government as part of the Australian Aquatic Ecosystem Toolkit and has been adopted by NSW DCCEEW Water as a progressive step to replace other NSW instream value assessments with a National approach. Although the HEVAE Framework advocates using five key criteria (Aquatic Ecosystems Task Group 20102a), NSW DCCEEW Water has adopted four criteria, diversity, distinctiveness, naturalness and vital habitat. Vital habitat data not able to be determined in the coastal HEVAE assessment due to lack of suitable data. Lack of State-wide data prevented inclusion of the fifth criterion (representativeness). Each of the four criteria relies on state-wide or regional availability of instream value data, to enable the production of consistent spatial mapping outcomes. Mapping outputs were derived at the river reach scale and the overall HEVAE scores identify where the best instream values occur within a catchment. The overall riverine HEVAE outcomes can be examined to determine which particular individual values (e.g. a threatened fish species in the Distinctiveness criteria) are influencing the final HEVAE scores. This [HEVAE report](https://water.dpie.nsw.gov.au/__data/assets/pdf_file/0019/207055/applying-the-HEVAE-framework-for-riverine-ecosystems.pdf) provides the rationale and describes the methods adapted from the Commonwealth HEVAE Framework for instream value and for each of the four criteria used. Details are provided on the weightings used, and scoring approaches, providing the overall HEVAE scores for each river reach. This dataset contains polyline features defining NSW freshwater riverine instream value. The dataset enables the inclusion of the most up-to-date instream value or asset information to inform water planning needs in NSW. It also spatially enables the identification of contemporary instream value data at the river reach scale, that can then inform water sharing rules at different scales required (e.g. management zone or surface water source), The dataset facilitates the generation of HEVAE outcomes to inform the risk assessment process and associated strategies in WSPs and WRPs, which are requirements under NSW legislation, as well as the Basin Plan. ----------------------------------- Note: If you would like to ask a question, make any suggestions, or tell us how you are using this dataset, please visit the [NSW Water Hub (within SEED) which has an online forum](https://water-hub.seed.nsw.gov.au/thread/search) you can join.