Introduction
Howleaky? A learning and decision support tool for exploring the impact of different land uses on water balance (runoff, drainage) and water quality (erosion, sediment and pesticide load).
Howleaky? is a simple interface to exiting models which aims to provide insight into the impact of different land uses on water balance and water quality. The key questions are, how much water is lost as run off and creates erosion, how much water leaks below the crop zone and moves toward the ground water system, with potential salinity risks, under different lands uses. Howleaky? aims to put simulation technology and the insights this can provide into more hands through more a more accessible interface. This information and insight should be useful when determining potential uses of land during development, or the implications of past land uses.
Objective
Provide a simple, accessible and realistic tool for exploring implications of climate, soil type, land use (including crops, pasture and trees) and management on water balance components, leading to:
Background
Simulation methodologies have much to add to the debate on land use changes. A need probably exist for provision of an analytic tool to explore and present impacts of alternative land uses and management on on and off_site water balance and sediment delivery, including salinity risk. While our current understanding of the science in these issues is incomplete (but still substantial), access to current science and simulation models is poor. Land planners and managers need to be able to explore implications of alternative land uses for a range of locations and land uses. Ideally, advice should be customisable for each location.
What's different to current approaches for erosion, water quality and drainage estimation?
Models and decision support products are available in a range of formats, address different issues and require different parameter values. This results in a daunting task for potential new users, particularly land planners and managers, and those who have to make decision on land uses with current legislative frameworks.
In the case of assessing soil erosion hazard, the Universal Soil Loss Equation (USLE) is currently used as the basis for erosion prediction. While this model provides sensible soil loss estimates for some land uses (Freebairn et al, 1989), it does not provide any insight into management effects on runoff, deep drainage, water quality or productivity changes. A daily water balance approach using existing tested models provides this greater capacity while enhancing transparency and educational value. The improved flexibility and more realistic estimation of natural resource processes promises delivery of a new generation of evaluation and decision support tools.
The approach has been to use existing components of available models (e.g. PERFECT, APSIM, GRASP) and build on our understanding of the scope for simple computer based decision support tools (e.g. Howwet? ,Howoften?, Browser, AgET)
Capability
Ability to explore interactions between climate, soil type, land use and management on; runoff amount and reliability, erosion, water quality ie sediment concentration and drainage below the root zone.
Outputs
Tables, graphs (time series, probability distribution, pie charts) that provide insight into why different systems perform differently, and present variability in time that often hinders. A range of output formats are designed to suite a wide range of users. For example, some users may be satisfied with a table of summaries, while other users will want to explore where a certain result was derived.
Availability
Howleaky? is at the prototype stage and will be tested with user groups in 2003.
Contact David Freebairn, Agricultural
Production Systems Research Unit, Department of Natural Resources and
Mines, PO Box 318, Toowoomba, Qld 4350.
Phone: 07 46 881 391
Fax: 07 46 881 193
Email: David.Freebairn@nrm.qld.gov.au