2nd MINEO Workshop - Orléans, December 2002 MINEO Hydrology, Hydrogeology and Transport Modelling Principal investigators : Stuart Marsh and Stephane Chevrel Collaborating organisation 1 : British Geological Survey Collaborating organisation 2 : BRGM

2nd MINEO Workshop - Orléans, December 2002 Introduction MINEO’s remote sensing workflow gives two major outputs for subsequent use:MINEO’s remote sensing workflow gives two major outputs for subsequent use: –terrain models via stereo aerial photography –contamination maps from hyperspectral data This talk describes their use in modelling:This talk describes their use in modelling: –pollution run-off and dispersal pathways –drainage contamination maps –groundwater vulnerability maps –groundwater flow models –transport network analysis Both GIS & numerical modelling are usedBoth GIS & numerical modelling are used Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Mapping run-off pollution dispersal pathways Application of flow-accumulation algorithm to DEMs enables :Application of flow-accumulation algorithm to DEMs enables : –modelling downstream run-off from source(s) of pollution (points or areas) –mapping surface pollution dispersal pathways Shows how run-off transported pollution gathers into the main drainage system and can pollute the hydrographic network downstreamShows how run-off transported pollution gathers into the main drainage system and can pollute the hydrographic network downstream Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Mapping run-off pollution dispersal pathways

2nd MINEO Workshop - Orléans, December 2002 Production of potential drainage contamination map Application of this technique at a regional scale enablesApplication of this technique at a regional scale enables –mapping the sensitivity of the drainage system to pollution –identification of areas most likely to be affected by pollution can be used in the performance ofcan be used in the performance of –risk analysis and management –prioritisation of detailed investigations and clean-up activities, remediation studies –assessment of the impact of planned polluting activities Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Production of potential drainage contamination map Uncontaminated Drainage Polluted Run-off Contaminated Drainage Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Production of potential drainage contamination map Uncontaminated Drainage Polluted Run-off Contaminated Drainage Polluted areas Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Groundwater vulnerability map Results of a multi-criteria GIS analysisResults of a multi-criteria GIS analysis performed from an extensive set of GIS-layersperformed from an extensive set of GIS-layers –geology (permability) –soils and land-use (holding capacity), –thickness of the vadoze zone, –characteristics of the aquifer (transmissivity), –topography (slopes) –potential evapo-transpiration –etc... Takes into account electrical conductivity (witnessing contamination) in layer-weighting calculationTakes into account electrical conductivity (witnessing contamination) in layer-weighting calculation Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Groundwater vulnerability map Lowvulnerability Highvulnerability Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Groundwater flow modelling Numerical Modelling used to assess where groundwater will flow away from mine siteNumerical Modelling used to assess where groundwater will flow away from mine site Inputs are the:Inputs are the: –identified contaminated site –digital terrain model This example:This example: –Cornwall, UK –Dave Noy’s work Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions Outer boundary of finite element mesh Zone of mesh refinement Mine waste location at the United Downs mine

2nd MINEO Workshop - Orléans, December 2002 Finite element mesh used for modelFinite element mesh used for model –8605 nodes and triangular elements 2D unconfined aquifer model2D unconfined aquifer model –Top surface at DTM, bottom at -100m OD –No flow around boundary, except where main valley exits model: a fixed head is imposed here –A Uniform infiltration rate of 50cm/yr and an isotropic, homogeneous hydraulic conductivity of 1.0e-6 m/s were used Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions MeshElevationsCalculated Flows

2nd MINEO Workshop - Orléans, December 2002 Heads and flows at the mine waste site Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions Solute concentrations overlain on DTM

2nd MINEO Workshop - Orléans, December 2002 Modelling pollution transport networks: examples from Wheal Jane in the UK The drainage network can be used to model transport from mine to estuaryThe drainage network can be used to model transport from mine to estuary Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 Modelling other transport networks HyMap identifies contamination along the roads around the Wheal Jane mine siteHyMap identifies contamination along the roads around the Wheal Jane mine site Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions

2nd MINEO Workshop - Orléans, December 2002 The outputs of the remote sensing study form the inputs to subsequent analysisThe outputs of the remote sensing study form the inputs to subsequent analysis Complex hyperspectral products need to be presented in simpler forms for GIS analysisComplex hyperspectral products need to be presented in simpler forms for GIS analysis GIS is a powerful tool to extend analysis over wide areas using multiple datasetGIS is a powerful tool to extend analysis over wide areas using multiple dataset Modelling can be undertaken by complex GIS and numerical modelling calculations and also using simple visual approachesModelling can be undertaken by complex GIS and numerical modelling calculations and also using simple visual approaches Modelling can often be applied equally at any of the sites; it is more generic than remote sensingModelling can often be applied equally at any of the sites; it is more generic than remote sensing Results can be fed more easily into management information systems than the hyperspectral dataResults can be fed more easily into management information systems than the hyperspectral data Conclusions Introduction Pollution Run-off Drainage Contam Groundwater Vuln Groundwater Flow Transport Network Conclusions