Hunter Rivers High Ecological Value Aquatic Ecosystem NSW Office of Water 20141124

Abstract

This dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied:

Instream value assessment developed to support water management activities in NSW is being updated with contemporary datasets. These datasets are integrated into the High Ecological Value Aquatic Ecosystem (HEVAE) framework, originally developed by the Department of Environment, Commonwealth of Australia. (see: http://www.environment.gov.au/water/publications/aquaticecosystems-

toolkit-module-3-guidelines-identifying-hevae). The framework incorporates river and/or flow related attributes associated with four of the five recommended HEVAE criteria: Diversity,

Distinctiveness, Naturalness and Vital Habitat. No data is available yet for the fifth criteria, Representativeness. HEVAE assessment is progressively being undertaken for NSW catchments where water planning activities are being undertaken. Attributes associated with each criteria are identified within each catchment of interest, in this case the Hunter Central Rivers. Available data must have spatial

information such as coordinates, or polygons that can be intersected by the key stream layer based on River Styles® river reaches. This enables river and/or flow related attributes that, could be impacted by extraction, to be associated with river reach spatial layer and enable HEVAE criteria to be displayed in ArcGIS. Depending on the criteria, attributes are weighted according to sensitivity to flow. Some attributes associated with the Distinctiveness criteria are also weighted according to threat status and the certainty or confidence surrounding the occurrence of each record. Scores are determined for each attribute in each criteria and are normalised to provide outcomes that range between 0 -1, where 1 represents the highest possible HEVAE outcomes for each river reach segment. Scores for each HEVAE criteria are combined to provide for a final or overall HEVAE score and assist to identify where priority river reaches occur. This provides a focus for where water sharing rules should be developed to minimise the impact of water extraction on instream values. NOTE: The data used in the Hunter-Central Rivers HEVAE Assessment represents a preliminary HEVAE assessment. Updates will occur to criteria such as Diversity (Fish diversity), Distinctiveness (threatened bird species), and Vital Habitat (Large woody debris and Dissolved Organic Carbon) as the data becomes available.

Purpose

Provide a useful framework that indicates the spatial location and importance (priority) of in-stream values to identify risk to in-stream values from extraction. Outputs will guide the development of water

access and trading rules being developed for NSW water sharing plans.

Dataset History

This dataset and its metadata statement were supplied to the Bioregional Assessment Programme by a third party and are presented here as originally supplied:

To compile the overall HEVAE outcomes for each river reach in the Hunter-Central Rivers catchment, the following data was compiled for each criteria. Flow sensitivity weightings were applied to all attributes, ranging from 1 to 4, with 4 indicating the highest sensitivity or reliance on river flow. Scores for each attribute and each criteria are normalised to enable scores to be allocated between 1 and 0, where 1 is the highest (best) outcome. Categories are determined and plotted on maps and can be either 3 or 5 categories. Three categories enable outcomes similar to the low, medium and high outcomes derived for macro water sharing plans, while five categories provide a greater level of range in outcomes within a catchment. Where data is available, HEVAE scores are reported at the river reach level. Diversity: Macroinvertebrate Family data is used for Macroinvertebrate.

Lineage Statement

Diversity and were obtained from the NSW Office of Environment and Heritage (J. Miller pers. comm.), who undertake regular AUSRIVAS monitoring in NSW. Data was collected at specific sites between 2004 and 2012. Macroinvertebrate scores were derived and placed into 4 diversity categories based on the number of Families recorded at each site. Fish Diversity data, also site- based, was obtained from the NSW DPI Fisheries. Data was derived from a State-wide sampling program dataset, with sampling occurring between January 2002 and 2011. Biodiversity scores were derived from the dataset, and placed into 4 fish diversity scores between 0 to 1 (highest). Site-based scores are associated with the river reach where sampling occurred and

upstream and downstream River Styles® category. Distinctiveness: Threatened species websites for NSW Office of Environment and

Heritage, NSW DPI Fisheries and the Commonwealth Department of Environment were evaluated using the available specific search tools

that could provide outcomes at catchment or NRM regional level. If there was uncertainty about the occurrence of a threatened species,

populations or endangered ecological communities, additional information (eg Profile of Final Determinations) on each relevant website was also inspected. Site based data was obtained from the NSW Atlas of NSW Wildlife. In addition to applying weightings of flow sensitivity, weightings related to threat status, and accuracy of record were also applied. Rare River Styles® were determined using the expert assessment by a river geomorphologist of the presence (by total reach length or proportion of lengths) of each River Style® category in proximity to strategic recovery reaches, the potential of overall River Style® to recover, level of isolation and representation of a particular attribute. The River Styles® spatial data is held by the NSW Office of Water. Naturalness: Initially, five attributes were used to report on naturalness, however the macroinvertebrate condition outcomes were removed due to the spurious outcomes this dataset influenced in the naturalness outputs. Flow sensitivity weightings of 1 are applied to each of the four remaining attributes. Attributes used in these criteria include: Geomorphic condition - was reported based on the mapped recovery potential outcomes of river reaches, that are closest to unimpaired or easily recoverable to natural conditions. Data was derived from the Office of Water The River Styles® spatial data. Hydrologic Stress - data is derived originally from the macro water sharing plan hydrologic stress assessment, and later from the River Condition Index Risk analysis. Hydrologic stress in the Hunter-Central Rivers region was calculated using two process, i) distributed hydrologic stress for most of the catchment and ii) macro water sharing plan hydrologic stress for the remainder, mostly smaller coastal catchment areas. Full details on each method can be found in the River Condition Index technical manual at:

http://www.water.nsw.gov.au/watermanagement/monitoring/catchments Catchment Disturbance Index (CDI) - Final catchment index scores developed for the NSW River Condition Index were used. Data custodian is the NSW Office of Water. CDI outcomes were derived from three sources: i) infrastructure (eg. Roads, railways, utilities...etc) density (from the Office of Water centralised Enterprise database), ii) land use index derived from the Australian Land Use mapping project based crop types, mining and urban uses, forest and plantations, grazing and managed resource areas, and iii) Land Cover Change Index based on loss of woody vegetation derived from the Land and Tree Study (SLATS) method applied by the NSW Office of Environment and Heritage. River reaches within National Park Estate - The National Parks Estate spatial layer was obtained from the NSW Office of Water Enterprise database. Where the National Park estate polygon intersected a stream (with a 50m buffer either side), a score of 1 was applied to the river reach. Remaining river reach scores were a 0. Vital Habitat: Only one attribute had useful spatial data for this criterion and related the occurrence of Directory of Important Wetlands Australia and RAMSAR wetlands. A 50m buffer along the River Styles stream line was used to intersect and vital habitat wetlands above the tidal limit. NOTE: Vital habitat was not included in the final HEAVE assessment due to some anomalies the attribute produced, however Vital Habitat maps were produced to assist with the assessment. The final or overall HEVAE score was determined for each River Style reach. This was calculated by adding together the final weighted and normalised scores for each criteria (Naturalness, Diversity and Distinctiveness - no Vital Habitat wetlands detected so not included in final computations). This score was then normalised by divided by the maximum combined HEVAE score for the whole Hunter Central Rivers river reaches to provide an even spread of score outcomes between 0 (lowest) and 1 (highest).

Dataset Citation

NSW Office of Water (2014) Hunter Rivers High Ecological Value Aquatic Ecosystem NSW Office of Water 20141124. Bioregional Assessment Source Dataset. Viewed 13 March 2019, http://data.bioregionalassessments.gov.au/dataset/13e78816-8852-4460-ae05-d5689e18dce0.