Assessing waterway health
Assessing waterway health
Assessing waterway health is a vital step in being able to manage our waterways effectively. Healthy waterways have intrinsic ecological value and provide a wide range of economic and social benefits to communities – see values for our waterways for information. Waterways are subject to a range of threats which can result in the degradation and loss of ecological, economic and social value.
Assessing the health of waterways, and the values they possess, requires a suite of indicators to provide information about current state, including pressures or stressors. The department uses a range of indicators to assess the health of waterways and to determine appropriate management requirements.
Many indicators are centred on the quantity and quality of water in waterways, but also include assessment of fish and crayfish, macroinvertebrates, aquatic and riparian vegetation, habitat and features of catchment disturbance.
Assessing estuary health
The Department of Water has developed a range of indicators to assess the health of estuaries. Assessments include understanding aspects of water quality, sediment quality, seagrass, macroalgae and phytoplankton, and catchment pressures such as river flows, land use and inputs. Integrated assessments of estuary health provide an understanding of current condition as well as inform on the likely responses of estuaries to additional pressures (e.g. climate or development). Estuary characteristics are published for the community:
Assessing river health
The Department of Water developed the South West Index of River Condition which uses multiple indicators to provide an integrated assessment of river health. This assessment tool has been used to help with water allocation planning in many rivers:
- Ecological study of the lower Canning River environmental water releases (below Canning Dam to Kent Street Weir)
- Ecosystem health in the Canning River, focusing on the influence of the Kent St Weir : assessed December 2009 - September 2011
- Assessment of low-flow thresholds in maintaining ecological health of the Gingin Brook : 2010-2011 dry season
- Assessment of low-flow thresholds in maintaining ecological health of the Lennard Brook : 2010-2011 dry season
- Assessment of ecological health and environmental water provisions in the Harvey River (between Stirling Dam and Harvey Reservoir) : February to May 2011
- Assessment of ecological health and environmental water provisions in the Logue Brook : February to May 2011
Other tools for focussing on specific aspects of river health are water quality monitoring and the Foreshore Condition Assessment.
The Department of Water also models the impact of land use change and nutrient export into our waterways.
The information gathered during river and estuary health assessments is used to underpin the management of our waterways.