Ecological risk assessments for Australia's Northern Tropical Rivers
- Cover page, table of contents, acknowledgements (PDF - 98.41 KB)
- Chapter 1 - Introduction (PDF - 567.75 KB)
- Chapter 2 - Identification of ecological assets, pressures and threats (PDF - 2.06 MB)
- Chapter 3 - Semi-quantitative risk assessments - The Relative Risk Model (PDF - 2.44 MB)
- Chapter 4 - Quantitative ecological risk assessments for the Daly River (PDF - 2.11 MB)
- Chapter 5 - Synthesis (PDF - 951.75 KB)
Sub project 2 of Australia's Tropical Rivers - an integrated data assessment and analysis (DET18)
A report to Land & Water Australia
R Bartolo, P Bayliss and R van Dam
Environmental Research Institute of the Supervising Scientist, 2008
About the report
This final report was submitted to Land & Water Australia in July 2008 and is composed of five chapters:
- Chapter 1 provides background and context of the sub-project, study area, description of ecological risk assessment, project objectives and scope, linkages to other Tropical Rivers Inventory and Assessment Project (TRIAP) sub-projects and report outline.
- Chapter 2 identifies and describes the ecological assets, pressures and threats for Australia's tropical rivers and the Daly River (NT), Fitzroy River (WA) and Flinders River (Qld). Includes assets-threats matrices.
- Chapter 3 is an application of the Relative Risk Model (RRM) as a regional risk assessment tool at two scales: The Northern Tropical Rivers; and the Daly River catchment. Multiple pressures/threats and multiple ecological assets are incorporated in the models.
- Chapter 4 provides quantitative ecological risk assessments for the Daly River (NT). The following ecological risks were modelled: risks of water extraction and weeds on floodplain health; risks of water extraction on in-stream health; and risks of land clearing on surface water quality. This chapter includes Bayesian Networks.
- Chapter 5 Summarises linkages with other TRIAP Sub-projects, links between tiered assessment phases, dealing with uncertainty, scenario testing, gap analysis and utility of ecological risk assessment tools and approach.
Background and Context
Australia's tropical river systems are unique and form one of the last great river networks in less-impacted condition in the world today. Together, they constitute an internationally significant asset (Australian Tropical Rivers Group 2004). However, increasing pressure on water supply and river systems in southern Australia is driving strong interest in the potential for greater use for agriculture of the perceived abundant water resources in northern Australia (Gehrke et al 2004). The existence of substantial mineral and energy resources in this region will further add to development pressures over the next 10-20 years.
To achieve sustainable development and growth in northern Australia, utilisation of the water resources of our tropical rivers will need to be balanced with providing appropriate protection of the riverine and wetland ecosystems, and the many benefits they provide to society. For this vision of sustainable development to be effectively realised, a better understanding of the aquatic ecosystems is required. However, these ecosystems have yet to be studied in a systematic manner. Across the Australian tropics it is generally only those catchments with existing mining, urban, or intensive agricultural development that have specific information available on ecology, biology, geomorphology, hydrology and management requirements. Consequently, the available information is fragmented and insufficient for addressing the management needs of the future (Land & Water Australia 2004).
Sustainable management of Australia's tropical rivers and wetlands will require an integrated information base for assessment of ecological character, status and change, and the development of policy, especially for environmental flows and potentially competing uses of water. To progress towards this goal the project Australia's tropical rivers - an integrated data assessment and analysis, more commonly referred to as the Tropical Rivers Inventory and Assessment Project, or TRIAP, was initiated in 2004. The overarching aim of the TRIAP was to establish an integrated information base and framework, built on consultation with stakeholders and analysis of existing information, for assessing status and change of Australia's tropical rivers (ie. river basins within the Timor Sea and Gulf of Carpentaria drainage divisions; referred to herein as the Northern Tropical Rivers).
Funded by the Natural Heritage Trust II and Land & Water Australia, and building on the information base compiled by NGIS (2004), the TRIAP consists of three Sub-projects:
- Inventory of the biological, chemical and physical features of aquatic ecosystems;
- Assessment of the major pressures on aquatic ecosystems; and
- Development of a framework for the analysis of ecosystem services provided by aquatic ecosystems.
The outcomes of Sub-projects 1 and 3 have been reported separately by Lukacs & Finlayson (2008) and De Groot et al (2008), respectively. This report presents the outcomes of Sub-project 2.
The conceptual basis for the TRIAP was provided by an integrated framework for wetland inventory, assessment and monitoring (WIAM; Figure 1.1), the most recent version of which was published by Finlayson et al (2005). The WIAM model, which has been formally adopted and promoted by the Ramsar Wetlands Convention, emphasises that although inventory, assessment and monitoring are discrete components, they are inter-connected and can operate at very different scales. For a given investigation, however, scale should be common across all three components to avoid information collected at one scale being used to make decisions or choices at another scale (Finlayson et al 2005). Thus, the multi-scalar nature of the WIAM framework is well-suited for analyses across an area as vast and diverse as northern Australia.
Although the existing biophysical information base for the Northern Tropical Rivers is known to be limited (relative to the size of the region), agricultural and mining development is already occurring and future opportunities are being actively and strategically explored on a northern Australian scale (Commonwealth Government of Australia 2007). Consequently, there is a need to assess the risks to aquatic ecosystems now, based on the best available information, rather than waiting until additional biophysical, socio-cultural nd economic data have been collected. Moreover, it is an appropriate time to be exploring methods and tools for assessing risk of current development and future development scenarios, including dealing with the uncertainties associated with limited data and knowledge.
This study, Ecological risk assessments for Australia's Northern Tropical Rivers, builds on recent efforts to develop ecological risk assessment approaches for Australia (eg. Hart 2004; Hart et al 2005), and applies some of these at various spatial scales across the Northern Tropical Rivers study area, thus providing some initial risk estimates for key pressures and threats to specific ecological assets.