MINEO

1
MINEO

• Hydrology, Hydrogeology and Transport Modelling

Principal investigators Stuart Marsh and
Stephane Chevrel Collaborating organisation 1
British Geological Survey Collaborating
organisation 2 BRGM
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Introduction

• MINEOs 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
• pollution run-off and dispersal pathways
• drainage contamination maps
• groundwater vulnerability maps
• groundwater flow models
• transport network analysis
• Both GIS numerical modelling are used

Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
3
Mapping run-off pollution dispersal pathways

• 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 downstream

Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
4
Mapping run-off pollution dispersal pathways
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Production of potential drainage contamination map

• Application 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 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
6
Production of potential drainage contamination map
Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
Uncontaminated Drainage
Polluted Run-off
Contaminated Drainage
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Production of potential drainage contamination map
Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
Uncontaminated Drainage
Polluted Run-off
Contaminated Drainage
Polluted areas
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Groundwater vulnerability map

• Results of a multi-criteria GIS analysis
• performed 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
  calculation

Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
9
Groundwater vulnerability map
Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
High vulnerability
Low vulnerability
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Groundwater flow modelling

• Numerical Modelling used to assess where
  groundwater will flow away from mine site
• Inputs are the
• identified contaminated site
• digital terrain model
• This example
• Cornwall, UK
• Dave Noys work

Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
Mine waste location at the United Downs mine
Outer boundary of finite element mesh
Zone of mesh refinement
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• Finite element mesh used for model
• 8605 nodes and 16892 triangular elements
• 2D 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
Mesh
Elevations
Calculated Flows
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Heads and flows at the mine waste site
Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
13
Solute concentrations overlain on DTM
Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
14
Modelling pollution transport networks examples
from Wheal Jane in the UK

• The 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
15
Modelling other transport networks

• HyMap identifies contamination along the roads
  around the Wheal Jane mine site

Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions
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Conclusions

• The outputs of the remote sensing study form the
  inputs to subsequent analysis
• Complex 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 dataset
• Modelling 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 sensing
• Results can be fed more easily into management
  information systems than the hyperspectral data

Introduction Pollution Run-off Drainage
Contam Groundwater Vuln Groundwater
Flow Transport Network Conclusions