Projects
Project 5 – Catchment Nutrient and Sediment Management
Leader: Dr Hamish Cresswell, CSIRO, Canberra
Objective
To better understand the sources, sinks and flow paths of nitrogen, phosphorous and sediment in catchments used predominately for agriculture (but might also include areas of forestry) so that effective management actions can be undertaken to reduce loadings in streams, rivers and estuaries.
Aims
To assist prioritization of investment aimed at maintaining or improving catchment water quality by identifying likely critical source areas for nutrients and sediments, and building conceptual ‘models’ of nutrient movement through the landscape and into receiving waters.
Approach
- Carry out high frequency water quality (including nitrate and ammonia) monitoring in a Tasmanian catchment (one where estuarine water quality impacts are also being monitored and analysed through Landscape Logic Project 4) and use the new data to explain the links between land use management and aquatic ecosystem impacts. This is the basis for new theoretical understanding and capability to link key measurements to actions on the land.
- Develop and apply new methods for identifying functional hydrochemical response units (landscape units that relate to dominant hydro-chemical process dynamics) as an element in advancing prediction of catchment scale water, sediment and dissolved nutrient dynamics.
- Use the above and develop descriptions of how diffuse pollutants move through catchments – descriptions that include how solutes move from individual response units through to a catchment outlet (i.e. sources, sinks and flow paths within a spatial framework). Use the technology to identify critical source areas for nutrient pollution (i.e. ‘hotspots’ which should be priorities for NRM investment).
Outputs (what and when)
- Spatial conceptual ‘models’ that represent new understanding of dissolved nutrient pathways including both source and sink behaviour (Jan 09)
- Recommendations to regional NRM organisations on types and locations of measurements that have high information content and are useful for monitoring and assessing the impacts of management interventions on catchment water quality. (Sept 08)
- Methods to identify the contribution of specific areas within a catchment to the end-of-catchment water and/or nutrient delivery – methods that use available data sets (eg. DEM, soil, vegetation, slope, rainfall) (Jun 09).
- Selected Tasmanian catchments disaggregated into landscape response units (Dec 07).
Outcomes
Addresses Landscape Logic Outcome 2, improved prioritisation for management of water quality through identification of critical source areas
- Critical source areas for dissolved nutrients and/or sediment identified in study catchments to guide prioritization of NRM investment
- New understanding of flow paths, sources, and sinks relevant to the movement of nutrients through the stream network to end-of -catchment
- New methods for disaggregating catchments into ‘Functional hydro-chemical Response Units (FRUs).
External collaboration and links
This research will take place in Tasmania together with Landscape Logic Projects 1 and 4. Catchments for field experimentation have not yet been selected, and this will be through a joint process with the other Tasmanian Landscape Logic projects, NRM regions, and stakeholders (April – June 2007). Project 5 will also provide new knowledge to the decision networks developed by Project 6, and work together with Project 7 on knowledge transfer. Projects 1 and 5 will cooperate on spatial analysis for Output 3. This project is also connected to the eWater CRC.
Scoping Process (how did we get there?)
The research described here is in response to partner NRM organisations expressing the need to determine:
- where in the landscape to target specific water quality related NRM interventions
- how to decide what are the appropriate water quality management options to use in an identified location
- how to assess the impact of such interventions before and after implementation.
Landscape Logic meetings, tours and workshops between August and December 2006 helped to establish research objectives. The Project 5 team has met with each the Tasmanian regional NRM partner organisations to discuss their needs and core business. Meetings have also been held between Projects 5, 1 and 4.
Click here to see the Project 5 poster (pdf, July 2007).
