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Using sediment budgets to investigate the pathogen flux through catchments
Tanya G Whiteway1, Shawn W Laffan, Robert J Wasson
1ECOWISE Environmental Fyshwick, Canberra, ACT 2609, Australia.
Environmental Management
|January 6, 2005
Summary
A materials budget approach identifies gullies as key sources of pathogens, using fine sediment flux as a proxy. Landscape modification and water flow significantly impact pathogen transport to reservoirs.
Area of Science:
- Environmental Science
- Hydrology
- Ecology
Background:
- Pathogen contamination of water bodies poses risks to ecosystem and human health.
- Identifying pathogen sources in landscapes is crucial for effective management strategies.
- Fine sediments are recognized as a primary transport medium for various pathogens.
Purpose of the Study:
- To develop and apply a materials budget approach for identifying pathogen sources and fluxes in a landscape.
- To use fine sediment flux as a proxy to infer pathogen movement and identify key contributing areas.
- To assess the influence of landscape modification and hydrological conditions on pathogen mobilization.
Main Methods:
- Construction of sediment budgets for three subcatchment tributaries.
- Estimation of sediment inputs, sources, stores, and transport zones.
- Utilizing sediment sampling, dam trap efficiency, radionuclide tracing, and particle size analysis.
- Inferring pathogen flux based on the mobility and transport characteristics of fine sediments.
Main Results:
- Gullies identified as significant sources of fine sediment and, consequently, pathogens.
- Pathogen risk is exacerbated in gullies used by cattle during wet periods.
- Landscape modification demonstrably influences both sediment and pathogen mobilization.
- Farm dams and specific landscape features reduce fine sediment and pathogen flux during low-flow periods.
- High-rainfall and high-flow events are the primary drivers for transporting sediment and pathogen loads to the reservoir.
Conclusions:
- The materials budget approach provides a repeatable and cost-effective method for investigating landscape-level pathogen fluxes.
- Gully erosion and cattle activity are critical factors in landscape pathogen contamination.
- Understanding hydrological dynamics is essential for predicting pathogen transport patterns.
- Management strategies should focus on mitigating erosion in gullies and considering the impact of landscape modifications on water quality.