NSW DoI Water has adopted the Guidelines for Identifying High Ecological Value Aquatic
Ecosystems (HEVAE) framework developed by the Australian Commonwealth
Government. In the current assessment for NSW, the HEVAE consists of four key criteria which include diversity, distinctiveness, naturalness and vital habitat. Therefore, the
HEVAE vegetation GDE value layer is a combination of four individual criterion layers.
The final or overall HEVAE score was determined for vegetation PCT polygons which has
a high probability of being groundwater dependent. This was calculated by adding
together the final scores for each criterion (Naturalness, Diversity, Distinctiveness and
Vital Habitat). This score was then standardised by dividing by the maximum combined
HEVAE score for a whole catchment’s vegetation GDE polygons to provide an even
spread of score outcomes between 0 (lowest) and 1 (highest). For ease of data
modelling and management, the dataset was divided into the following catchment
management areas; Border Rivers-Gwydir, Central Tablelands, Central West,
Hawkesbury-Nepean, Hunter-Central Rivers, Lachlan, Lower Murray Darling, Murray,
Murrumbidgee, Namoi, Northern Rivers, Southern Rivers, Southern Tablelands, Sydney
Metro and Western Division (subdivided further into the IBRA Sub regions). *Currently
only the MDBA Catchments have been completed.
