Testing the Framework for the Assessment of River ...

Testing the Framework for the Assessment of River and Wetland Health in New South Wales wetlands

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Prepared by: Eren Turak, Rachel Melrose, Tariful Islam, Sarah Imgraben and Rachel Blakey Rivers and Wetlands Unit Office of Environment and Heritage Department of Premier and Cabinet

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With the exception of photographs, the Office of Environment and Heritage, Department of Premier and Cabinet (OEH) and State of NSW are pleased to allow this material to be reproduced in whole or in part for educational and non-commercial use, provided the meaning is unchanged and its source, publisher and authorship are acknowledged. Specific permission is required for the reproduction of photographs. OEH has published this document in good faith, exercising all due care and attention. No representation is made about the accuracy, completeness or suitability of the information in this publication for any particular purpose. OEH shall not be liable for any damage which may occur to any person or organisation taking action or not on the basis of this publication. Readers should seek appropriate advice when applying the information to their specific needs. Published by: Office of Environment and Heritage, Department of Premier and Cabinet 59–61 Goulburn Street PO Box A290 Sydney South 1232 Report pollution and environmental incidents Environment Line: 131 555 (NSW only) or [email protected] See also www.environment.nsw.gov.au Phone: (02) 9995 5000 (switchboard) Phone: 131 555 (environment information and publications requests) Phone: 1300 361 967 (national parks, climate change and energy efficiency information and publications requests) Fax: (02) 9995 5999 TTY: (02) 9211 4723 Email: [email protected]

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ISBN 978 1 74293 356 6 OEH 2011/0779 September 2011 Cover photo: Gwydir wetlands – J Spencer, OEH

This project was funded by the Australian Government through the National Water Commission’s Raising Water Standards Program.

Summary The Framework for the Assessment of River and Wetland Health (FARWH) aims to facilitate nationally comparable regional assessments of river and wetland health across Australia at the scale of surface water management areas (SWMAs). All previous trials of FARWH were confined to river systems. In this first application to wetlands, five SWMAs in New South Wales were assessed: Murray, Murrumbidgee, Hunter, Karuah and Manning. Existing wetland maps for these areas did not adequately cover major wetland types, so one of the first steps taken in this trial was to complete wetland mapping. A total of 30 296 wetlands with a surface area of 468 143 hectares were mapped in this process. Attributes of the mapped wetlands, including climatic variables, soil types, elevation, wetland area, ratio of area to wetland perimeter, and the furthest distance between the wetland and any point in its catchment, were used to develop wetland typology by applying multivariate classification techniques. A single typology was developed for the Hunter, Karuah and Manning SWMAs, where five wetland types were defined. The typology for the Murray SWMA also defined five wetland types, while the one developed for the Murrumbidgee SWMA defined seven wetland types. The data available for assessing wetland condition in any of the SWMAs was limited, allowing assessments to be made for only three of the six FARWH themes: catchment disturbance, water quality, and fringing zone. Catchment disturbance was assessed using the Wetland Catchment Condition Index (WCCI), which was the average of three indices: an index of local land use surrounding the wetland; an index of all local anthropogenic disturbances in the vicinity of the wetland; and an index of cumulative disturbances in the entire catchment of the wetland. Water quality was assessed using the Wetland Water Quality Index (WWQI), which was derived from measurements of electrical conductivity, pH and turbidity. The condition of the fringing zone was assessed using the Fringing Zone Structural Index (FZSI), which measured the extent of woody vegetation in the fringing zone. The WCCI and FZSI were calculated for all wetlands, but the WWQI was calculated for only the small number of wetlands in each SWMA for which suitable water quality data was available. The reference condition was set at 0 for the WWCI and at the index value of least disturbed wetlands for the FZSI. For the WWQI, the reference condition was determined by extrapolating from the median value for observations that were in the interquartile range of disturbance (WCCI). Index values were aggregated by averaging index values for all wetlands, weighted by wetland area. Aggregation was performed for each of the SWMAs for each wetland type separately and then for all wetlands, regardless of type. Aggregated values were also calculated for subcatchments of two different sizes (small and large) in the Hunter SWMA and for large subcatchments only in the four other SWMAs. These aggregations were performed only for the WCCI and the FZSI and were not type-specific. The SWMA-level aggregated values for the indices (WCCI, WWQI and FZSI) were integrated to generate a single Wetland Condition Index (WCI) for each SWMA. The overall condition of the five SWMAs measured by the WCI suggested that the wetlands of the Karuah SWMA were in the best condition (0.78) and those of the Murrumbidgee SWMA were in the worst condition (0.37). The Murray SWMA (0.49) was also assessed to be in poor condition, while the Hunter (0.59) and the Manning (0.63) were assessed to be in better condition than both the Murray and the

Murrumbidgee. The distinctions among the SWMAs were greater for water quality and fringing zone condition than for catchment condition. Wetland type influenced condition assessments for all three themes and in all SWMAs, but this influence appeared to be greatest in the Murrumbidgee SWMA and for water quality. Aggregations performed at the subcatchment level showed greater variation among subcatchments in fringing zone condition compared with catchment disturbance. In the Hunter SWMA, large variations in condition were observed both for the small subcatchments and the larger ones. This trial has shown that better data and wetland mapping, and further development of indices are needed before the FARWH can be used to generate useful broadscale assessments of wetland health in NSW. Nevertheless, great progress towards this goal has been made in this trial, including the development of wetland mapping methods that can be applied across Australia with limited resources, procedures for selecting reference wetlands, development of regional wetland classifications using remotely derived data, and methods for assessing catchment condition, fringing zone condition and water quality for wetlands at broad spatial scales. Successful implementation of a wetland assessment program in NSW will require the development of broadscale monitoring programs, especially for biota and water quality, as well as improvement of wetland mapping and the development and validation of ecologically meaningful wetland typologies. These necessary next steps are outlined in an implementation plan for a FARWH-based, statewide wetland assessment program in NSW.

Contents Introduction ................................................................................................................1 Methods ......................................................................................................................3 Scope of the trial ......................................................................................................3 Definition of wetlands ...........................................................................................3 FARWH themes assessed ...................................................................................3 Trial areas ............................................................................................................3 Mapping ...................................................................................................................6 Limitations of mapping methods.........................................................................10 Alignment of FARWH wetland mapping to draft national standards ..................10 Wetland typology....................................................................................................11 Indicator development............................................................................................12 Catchment disturbance ......................................................................................12 Fringing zone......................................................................................................14 Water quality ......................................................................................................15 Wetland loss.......................................................................................................16 Setting reference conditions and final scoring .......................................................16 Results ......................................................................................................................17 Wetland maps and types........................................................................................17 Catchment disturbance ..........................................................................................21 Fringing zone .........................................................................................................22 Water quality ..........................................................................................................23 Integration of themes .............................................................................................23 Spatial scales of aggregation and reporting ...........................................................27 Geodatabase and applications...............................................................................36 Geodatabase development ................................................................................36 Applications ........................................................................................................36 Implementation plan for the assessment of wetland health ...................................36 Discussion ................................................................................................................38 Conclusions..............................................................................................................39 Glossary....................................................................................................................41 References................................................................................................................42

Testing the FARWH in NSW wetlands

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Figures Figure 1: Figure 2: Figure 3: Figure 4: Figure 5: Figure 6: Figure 7: Figure 8: Figure 9: Figure 10: Figure 11: Figure 12: Figure 13: Figure 14: Figure 15: Figure 16: Figure 17: Figure 18: Figure 19: Figure 20: Figure 21:

Overview of the components and framework used to apply the FARWH to wetlands in NSW............................................................................................... 2 The SWMAs chosen for the trial of FARWH in NSW wetlands ......................... 4 The five processes for developing wetland extent maps for each SWMA ........ 7 Imagery (SPOT 5 2008) within the Murrumbidgee SWMA illustrating rules for wetland delineation.......................................................................................... 9 Wetland types (where allocated) and their extent in the Hunter, Karuah and Manning SWMAs and the main channels of the three major rivers (Hunter, Karuah and Manning). ........................................................................................ 18 Wetland types (where allocated) and their extent in the Murrumbidgee SWMA and the main channel of the Murrumbidgee River. .............................. 19 Wetland types (where allocated) and their extent in the Murray SWMA and the main channel of the Murray River............................................ 20 The WCI representing the integrated wetland condition assessments for the five trial SWMAs ...................................................................................... 24 Condition assessments for each wetland type in the Murrumbidgee SWMA using the three condition indices WCCI, FZSI and WWQI .................. 24 Condition assessments for each wetland type in the Murray SWMA using the three condition indices WCCI, FZSI and WWQI ............................... 25 Condition assessments for each wetland type in the Hunter SWMA using the three condition indices WCCI, FZSI and WWQI ............................... 26 Condition assessments for each wetland type in the Manning SWMA using the three condition indices WCCI, FZSI and WWQI ............................... 26 Condition assessments for each wetland type in Karuah SWMA using the three condition indices WCCI, FZSI and WWQI ............................... 27 FZSI for 172 small subcatchments used for water planning in the Hunter SWMA ..................................................................................................... 28 WCCI for the 172 small subcatchments used for water planning in the Hunter SWMA ..................................................................................................... 29 FZSI for the large subcatchments in the Hunter Karuah and Manning SWMAs 30 WCCI for large subcatchments in the Hunter, Karuah and Manning SWMAs 31 FZSI for subcatchments of the Murray SWMA ................................................. 32 WCCI for subcatchments of the Murray SWMA ............................................... 33 FZSI for subcatchments of the Murrumbidgee SWMA..................................... 34 WCCI for subcatchments of the Murrumbidgee SWMA................................... 35

Tables Table 1: Overview of SWMAs chosen for NSW FARWH trial.............................................. 5 Table 2: Overview of water quality data available from the main sources......................... 15 Table 3: The number of water quality sampling sites that fall within wetlands and the total number of mapped wetlands in each SMWA. .............................................. 15 Table 4: The surface area of each of the trial SWMAS, the area covered by the mapped wetlands and the number of individual wetlands (polygons) mapped................. 17 Table 5: Catchment condition, number of wetlands assessed and the total surface area covered in the five trial SWMAs reported for the whole SWMA and separately for each wetland type........................................................................... 21 Table 6: FZSI value reported separately for wetland types................................................ 22 Table 7: WWQI for different types of wetlands in Hunter, Karuah and Manning SWMAs................................................................................................................... 23 Table 8: Tasks that need to be completed under the implementation plan and the resources required ................................................................................................. 37

Introduction The National Framework for the Assessment of River and Wetland Health (FARWH) was developed as part of the Australian Water Resources (AWR) 2005 project funded by the Raising National Water Standards (RNWS) Program. The Australian Government’s $250 million RNWS Program, administered by the National Water Commission (NWC), supports the implementation of the National Water Initiative (NWI) by funding projects that are improving Australia’s capacity to measure, monitor and manage our water resources (Norris et al. 2007). The Australian Government NWC is managing the implementation of the NWI, which has been signed by the Commonwealth and all states and territories. It is Australia’s blueprint for national water reform to improve water management across the country. The overall objective of the NWI, which includes a range of water management issues and encourages the adoption of best-practice approaches, is to achieve a nationally compatible market and a regulatory and planning-based system for managing surface and groundwater resources for rural and urban use that optimises economic, social and environmental outcomes. The primary aim of the FARWH was to enable locally relevant, comprehensive assessments of river and wetland health to be comparable across jurisdictions. FARWH uses a referential approach, assuming that ecosystem health can be measured in the currency of ecological integrity (Karr and Dudley 1981), which may be defined as the degree of departure from a reference condition (Schofield and Davies 1996; Reynoldson et al. 1997; Norris and Thoms 1999). FARWH uses six key components that are appropriate for assessing river and wetland health, all of which are considered to represent ecological integrity: 1 physical form 2 water quality and soils 3 aquatic biota 4 hydrological disturbance 5 fringing zone 6 catchment disturbance. To achieve nationally consistent reporting, the default spatial scale of assessments and reporting in FARWH was set as surface water management areas (SWMAs) (Norris et al. 2007). These are typically large river catchments. In the Murray–Darling Basin the SWMAs often have similar boundaries to those of the catchment management authorities (CMAs), but in eastern New South Wales typically several SWMAs are included in one CMA region. Some of the NSW catchments were divided into regulated and unregulated SWMAs. For this trial we have combined these into a single region. This report presents findings of the RNWS-funded project, Testing the Framework for the Assessment of River and Wetland Health (FARWH) in New South Wales Wetlands.1 The objectives of the project, listed in the inception report, were as follows:  develop a framework to achieve comparable assessment of wetlands across CMA regions and SWMAs in NSW, using the FARWH  apply the framework to existing data from selected regions in NSW

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www.nwc.gov.au/www/html/461-farwh-in-nsw.asp?intSiteID=1

Testing the FARWH in New South Wales wetlands

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 based on the results of this trial, identify data requirements to assess the ecological health of wetlands at the scales of the entire state, CMA region and SWMAs  identify modifications to and directions for the FARWH and wetlands monitoring, evaluation and reporting (MER) programs for NSW (i.e. using outcomes from objectives 1–3)  communicate the process and outcomes of the trial to stakeholders. To meet these objectives, it was necessary to address some key issues that relate to the application of the FARWH to wetlands. These issues include spatial scales of reporting, definition of reference conditions, selection of indices to represent the different components of the ecosystems, methods for integrating and aggregating different indices, sensitivity analyses, range standardisation and managing missing data. We attempt to address each of these issues in relation to selected wetlands in NSW, with the expectation that the results can be readily applied in other parts of Australia. The main steps taken during this project are shown in Figure 1.

Figure 1: Overview of the components and framework used to apply the FARWH to wetlands in NSW

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Methods Scope of the trial Definition of wetlands Wetlands were defined by Cowardin et al. (1979) as:  being inundated permanently, periodically or intermittently with non-flowing water  supporting plants and animals that are adapted to and dependent on living in wet conditions for at least part of their life cycle  having a substratum consisting of predominantly undrained soils that are saturated, flooded or ponded long enough to develop anaerobic conditions in the upper layers. Riverine estuarine and marine wetlands were excluded from the trial. FARWH themes assessed A major constraint of this trial was the availability of suitable data. Hence the themes were chosen in accordance with existing data that was readily available for analysis. Three of the six FARWH themes were assessed in this trial:  catchment disturbance  fringing zone  water quality. Trial areas Five SWMAs in NSW were chosen to be included in this trial (Figure 2):  Murray (NSW part only)  Murrumbidgee  Hunter  Karuah  Manning. The SWMAs were chosen to make best use of the available data and include a range of catchment sizes, environmental conditions, wetland types and pressures. Table 1 describes the environmental and socioeconomic features of each SWMA.

Testing the FARWH in NSW wetlands

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Manning Hunter

Karuah

Murrumbidgee Murray

Figure 2:

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The SWMAs chosen for the trial of FARWH in NSW wetlands

Testing the FARWH in NSW wetlands

Table 1: Overview of SWMAs chosen for NSW FARWH trial * SWMA

Catchment size (km2)

Water resource development

Human population

Climate

Av. annual rainfall range (mm)

Pressures

650–1100

Power generation, coal mining, heavy industry, irrigated agriculture, urban infrastructure, fisheries.

Hunter

21 500

High

~600 000

Coastal temperate to upland

Karuah

4500

Low

~65 000

Coastal subtropical and temperate with small upland component

950–1300

Beef cattle production, open cut mining, tourism, recreational fishing.

Manning

8190

Low

~45 000

Coastal subtropical to upland

850–1500

Dairy production, oyster farming, coal mining, gravel extraction, agriculture, forestry, fisheries.

Murray

37 197

Over-developed

~75 000

Temperate to semi-arid

350–650

Agriculture, e.g. rice, wool, dairy, wheat, beef, lamb, grapes, citrus. Also tourism and recreation.

Murrumbidgee

85 5802

Over-developed

~545 000

Alpine to semi-arid

350–1500

Irrigated agriculture – rice production, viticulture, horticulture.

* Water resource development categories represent the magnitude of water use as a percentage of sustainable flow regime (surface water) and sustainable yield (groundwater): low: