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Learn about SCIMAP approach for diffuse pollution protection in catchments. Real world applications, training, and uncertainty analysis covered.
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Integrated land-water risk analysis for the protection of sensitive catchments from diffuse pollution Reaney S M (1&2), Lane S N (1), Heathwaite A L (2) and Dugdale L (1&3) Department of Geography, Durham University, UK Centre for Sustainable Water Management, Lancaster Environment Centre, Lancaster, UK Eden Rivers Trust, UK
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The nature of diffuse pollution • Diffuse pollution has some special characteristics: • spatially-distributed • spatially-structured • time-varying • above ground and below ground • The source of a in-stream problem may be • Extensive • Hidden from view
The SCIMAP approach • Based on the approach • Risk + Connection = Problem • Focus on the connectivity • Integrates long term behaviour • Based on a probabilistic framework • Considers surface runoff and near surface flows • Integrated consideration of uncertainty
Example Application of SCIMAP – Fine Sediment The River Eden Catchment, UK
Testing of the approach • River Eden catchment • Electrofishing • Annual sampling by Environment Agency and the Eden Rivers Trust • Across 2,309 km2 • 280 sites per year • Salmon parr and fry • Trout parr and fry • Spatial water quality sampling • 211 samples collected within 3 hours • Across 614 km2 • Analysed for Nitrogen, Phosphorus and Potassium • Potassium results presented today
Electro Fishing Results Acknowledgement: Eden Rivers Trust
Potassium and Risk Using only the surface flow index No land use weighting
Assessment of land cover riskuncertainty • Sensitivity of the approach to land cover risk parameterisation • GLUE type framework • 30,000 parameter sets investigated • Uniform distribution • No assumed relationships between parameters • Assessed against the • electro-fishing data for 2002 • Spatial water quality sampling for NO3
Uncertanity results presentation • Determine an objective function (OF) • Find the best OF values (minimum 10) and work out mean and standard deviation of parameter values that give best results • Add in next best OF • Plot the weightings against the objective function
Expression of uncertainty in the risk maps • The fittest 0.1% parameter sets used for the uncertainty analysis • Mean and coefficient of variation calculated • Colour of the in stream points determined by the mean • Size of the points related to the variation in the sample results
Thin green lines = low risk but low certainty Wide red lines = high risk and high certainty
Conclusions • SCIMAP offers a risk mapping framework • Explicit handling of spatial risk connectivity • Based on available data • Simple to apply to new locations • Low cost • Integrated assessment of parameter uncertainty • Currently being tested • With physical and ecological data • Uncertainty analysis of model structural options • Flow routing, slope determination, rescaling of risk, etc • Will be expanded to consider • Nitrogen • Phosphorus
For More Information • Email: • info@scimap.org.uk • Web: • www.scimap.org.uk