Projects
Project 4 – Tasmanian Retrospective Study (Water Quality and Yield)
Leader: Dr Bill Cotching, Tasmanian Institute of Agricultural Research, UTAS Burnie.
Objectives
To establish water quality responses to changes in land use and land management, and how water quality in turn affects riverine and estuarine health and function.
Aims
- Identify relative impact of land use, land management and previous landscape interventions on water quality.
- Provide new knowledge and improved assumptions about the responsiveness of river health to water quality as a result of historic changes in land resource parameters.
- Provide new knowledge and improved assumptions about responsiveness of estuarine health to water quality as a result of historic changes in land resource parameters.
Approach
1. Land use and land management change:
- At catchment scale, examine relationships between historic data on water quality and land use for multiple Tasmanian catchments, model nutrient and sediment outflows to characterize responses for local catchments by geomorphic settings, and model water quality response to land use using the model CMSS.
- At paddock and sub-catchment scale, relate historic satellite imagery and aerial photography to water quality data for case studies of interventions, and record social and policy drivers for changes (e.g. riparian zone fencing & revegetation, stock crossings),
- Use process-based models (e.g. E2) of hydrochemical response for forest and pasture-dominated riparian zones in agricultural landscapes to identify hydrologic flowpaths and predict down-stream water impacts,
- Integrate outputs from E2, APSIM and GIS analysis into CatchMODS to simulate the effects of paddock to sub-catchment management activities on water quality in 2-3 case study catchments.
2. River health
- Explore relationships between land use change, water quality and habitat characteristics and key components of river ecosystem health using existing data sets and field sampling.
- In the absence of good time series data, explore relationships between land use change, water quality and habitat characteristics and key components of river ecosystem health using space-for-time experiments (data from many catchments at one time with and without intervention rather than one or two catchments over long periods of time)
3. Estuarine health
- Examine the relationship between landuse history (derived by the Spatial Information project team) and existing data on water quality, flow and estuarine health.
- Explore relationships between landuse at regional and catchment scales, water quality and quantity and a variety of indicators of estuarine health by re-visiting some of the 22 Tasmanian estuaries sampled in the mid-late 1990’s.
- Analyse sediment cores from selected estuaries to relate historic land use change to estuarine health using a range of established proxies for the age of sediments (e.g. the lead isotope Pb210) and the state of estuarine processes.
4. Riparian Vegetation
- Focus on water quality responses derived from investing in riparian buffer zones in Tasmanian Catchments.
Outputs (what and when)
| 1. | A conceptual response framework that links changes in land use and land management, key water quality variables, and river and estuarine condition (Dec 2008 – June 2010) |
| 2. | Evaluation of past intervention for environmental management (2008-2010). |
| 3. | Identification of critical source areas to aid prioritization of efforts to improve water quality and selection of specific mitigation strategies (through a) water quality triggers based on relationships between water quality/quantity and indicators of river and estuarine condition, b) evaluation of the relationship between land use and river and estuarine health, c) evaluation of the effects of NHT/NAP investment in land use change on river and estuarine health, d) evaluation of environmental management options for improving and maintaining river and estuarine health, e) improved understanding of river and estuarine dynamics.) |
| 4. | Multi-objective planning tools based on a range of decision networks. Outputs for the parameterization of decision support tools (e.g. BDNs) will be developed by the Knowledge Integration team with the aim of supporting decision making linking land use management interventions and estuarine health symptoms and triggers (2007-2010). |
| 5. | Regional staff in each partner region with greater knowledge for use in multi-objective planning tools (2007-2010). |
| 6. | Better quality information on response to intervention for emerging markets in natural resources (2008-2010). |
| 7. | Publications, reports, training workshops and manuals (2007-2010) |
Outcomes
| 1. | Improved understanding of the effectiveness of past intervention (through a) improved understanding of the link between land use, subsequent effects on water quality and quantity and ecosystem health at the bottom of the catchment, b) improved understanding of the effectiveness of past land use change and intervention for maintaining/improving river & estuarine health, c) improved understanding of relationships between land use, water quality, quantity and river & estuarine health, d) validation and refinement of indicators, sampling design and trigger levels to monitor change in river & estuarine ecosystem health, e) improved management of investment in river & estuarine condition through better understanding of responses to land use change and management). |
| 2. | Improved prioritization for management of water quality through identification of critical source areas. |
| 3. | Social learning about the inter-dependencies between management decisions through the development and use of multi -objective planning tools that capture quantitative and qualitative information. |
| 4. | Tools designed with regional organizations for multi-objective natural resource planning and investment. |
| 5. | Improved management and investment in natural resources through better understanding of response to management. |
External collaboration and links
- Sub-project 1 has links to the CSIRO frameworks for modeling agricultural systems, DPIPWE pilot project on the spatial recording of land management practice information funded by the Land and Water Audit, DPIPWE Water Assessment Branch work on water quality trigger values, NRM agencies and local government for location of subcatchments where retrospective interventions have occurred
- Sub-project 2 has links to the Forestry CRC/Freshwater Systems project evaluating the influence of forest management history on river ecosystem condition in northern Tasmanian.
- Sub-project 3 has links with NAP funded Holistic Flows project and the FRDC funded project on Environmental Flow Requirements in Little Swanport.
- Sub-project 4 has links to Ensis joint venture
Scoping process (how did we get here?):
In December 2006 Landscape Logic held a two day engagement and research planning workshop. Three core questions were identified as important to the Regional NRM Agencies at this workshop, and the three integrated activities comprising the Tasmanian Retrospective study are designed to collectively address these. These three core questions are:
- Is the end of catchment a good indicator of the whole system in terms of water quality and quantity? What is the impact of pollutants on estuarine systems?
- How does land use and land management affect water quality and quantities? How do best management practices for various end uses affect water yield and water quality?
Are national water quality standards relevant to Tasmania? Are they relevant at regional and sub-regional scales? What should the trigger values be here? What is the point of monitoring if it is not relevant to our management actions? What are background or natural levels of pollutants versus human induced change?
Click here to see the Project 4 poster (pdf, July 2007).
