Groundwater Modellers’ Forum
Workshop on Groundwater – Surface Water Interaction, 28 Mar 07,
Birmingham
Transcription of Flipcharts from afternoon Break-out Groups
WETLANDS 1
Rapporteur: Loic Ragas
General comments
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Link ecology and hydrogeology;
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Historical:
o Analysis of ecological health,
o Analysis of historical hydro. data,
o Case studies for wetlands with historical data,
o Combination of both qualitative and quantitative information
Ecology
Water Levels, Flows
Nutrients, pH
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Future:
o Co-ordination in monitoring (location, timescale)
Actions
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Soil moisture monitoring
Develop and understand soil moisture
Statistical method to link ecological and hydro. data –
GIS (water quality & resources)
Resources of Natural England
“Sacrifice the patient” – Wetlands test? (Worst case)
Potential R + D Subjects
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“Single cell” model and soil moisture, etc (EA/NE/Consultants)
Unsat Zone “object” for zoom
Collation of “conceptual stores” for different types of rivers (eg, Drift/non-Drift/Chalk/Sst)
Better representation of UZ to replace transfer functions for recharge
GIS/Geostats. to assess hydro-ecological dependencies
Anthrop influence on GW flooding in urban areas
Routine, quantified ecological monitoring
More “3-Dness”, esp. vertical “refinement”
“Resilience” of ecol. Communities (timing of events)
High res. RF data (radar) – what effect does this have on our understanding /modelling of
recharge
Immediate Actions
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Better communication!!!
Continue monitoring (+ report!) after “events” (eg, GW flooding)
Agency (or others?) need “banked” monitoring budget to respond quickly to “events”
WETLANDS 2
Rapporteur: Mark Whiteman
Questions
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What are wetlands? (in modelling context)
Scale issues – how do we represent local processes in regional models?
What practical solutions exist for assessing impacts?
How can we improve collaboration between hydrogeologists/modellers + ecologists to
assess wetland impacts?
Scale issues
1) Say something in modelling/eco-hydrological guidelines about what wetlands are and how
they depend on groundwater
2) Regional models provide context – cannot give all the ecologically relevant detail
o Data availability is a limiting factor
o Need different approaches (could be analytical)
Site observations are important
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Need to consider scale issues during conceptual stage of modelling, do this early on in
modelling study eg, build model with knowledge of local detail
Wetmecs useful to start conceptualisation at wetland scale, and to interpret results of
regional model (could impact affect Wetmec process?)
Can’t understand all wetlands in detail – need to focus on a few sites for detailed studies
(eg, AMP, RSA sites have collected valuable data)
Practical solutions?
Collaborative R&D, how to handle local scale with simple modelling (eg, EA, Motts, Cranfield +
Entec study)
- Water needs of plant communities
- Putting impacts in context of natural variations
- Single cell model – statistical treatment
- A bit like contaminant transport – a lot of uncertain parameters – so need empirical
methods to correlate signal from regional model with ecology/hydrographs
- Simple field measurements eg, hand auger to characterise site – tiered
assessment, conceptual approach
Simple tools
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Understanding surface geology – simple site surveys, may identify control structure as
critical (eg, in river), and avoid need for detailed (numerical) model
Need to provide interpretation of details within model grid cell for stakeholders (eg,
ecologists, water companies)
Some situations eg, Karst - have to do simple calcs. to demonstrate impact is unlikely,
then monitor to mitigate
Habitats Directive
- Have to communicate where decision can’t be safely made
- Decision could be plan with actions, monitoring, alternatives
- Needs good base of understanding
- Identify sites where it really matters (drop ones where no impact)
Collaboration/communication
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more reports/knowledge dissemination
quick assimilation
conceptual model as a communication tool – local, for site, conceptual models are not
always right!
Site specific
Need for field visits
Use to focus monitoring
Wetmecs not intuitively obvious processes to hydrogeologists
Common language – hydrogeologists + ecologists
Wetland Framework Report should help
General recommendation
 Need participation from Natural England in modelling studies (as well as Water
Companies)
 Build publication of results into modelling projects (as part of conditions of engagement)
o Web-based, not just journals
o More than one website eg, UK GW Forum, Natural England
o Links between websites (must keep updated!)
o “Professional user” area on website?
 Water Companies – need info. to know where to monitor
 Case studies – knowledge….need tool for assessing this N.B. quality may vary,
practical, not academic
IMPACT ON RIVER FLOWS 1
Rapporteur: Andrew Hughes
CONSENSUS - IMPACTS
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Wide variety of model use for river-aquifer interaction
Grid refinement could handle the scale issue, but…
Recharge and runoff - need to get right (hydrological approach)
Pumping test analysis – how useful is it?
Monitoring
o Piezometers
o Ecological
RESEARCH ISSUES
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Communication!! LOCAR/CHASM
Novel measurement techniques, eg temperature
Model development – testing at appropriate scales, eg pumping test at LOCAR nv-aq site
Cross-disciplinary work, eg geomorphologists
IMPACT ON RIVER FLOW 2
Rapporteur: Dirk Liss
Specific questions
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Primary objective of GW models should be to improve the concept model in order
answer specific questions eg, low flows, abstraction stress, ecology
Model representation
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Limitation in model representation/implementation e.g. some conceptual ideas cannot
be represented accurately using the existing model packages
Compromise on scale
We need to understand bigger picture first before we deal with local issues
Individual features might dominate local scale
We do well
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Regional scale analysis (Aggr. Abs, Other Storage)
Support schemes
Improvements needed
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Extent of conceptual model to include the river systems accurately
Transient responses – head dependent conductance can not be represented using
MODFLOW streams -> R&D project should investigate this further
GROUNDWATER FLOODING
Rapporteur: Janet Riley
Definition: Clear water flooding which negatively impacts human activity/infrastructure
Groundwater breaking surface
Excessive recharge
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X
X
Groundwater rebound
Basement flooding
CONCEPTUAL MODELS
Mechanistic model: Good for future climate change interpretation
Statistical models: Also important for first pass prediction
DATA
Remote sensing
Radar – rainfall
Landsat
Video
Reports
Analysis: why did water not get away.
Anthropogenic effects: modified drainage.
CONCEPTUAL MODELS
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Susceptiblity – done
Temporal predictions (to do)
o Needs further assessment of objectives
o May not need models, probably only monitoring.
RESEARCH
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UZ/recharge (BGS/IC)
Spacial and anthropogenic mapping of risks (ongoing)
Historical analysis of flooding events (needs doing)
Methods of gathering data (RS, GIS)
ATTENTUATION IN THE HYPORHEIC ZONE
Rapporteur: Nick Woodman
How to use this knowledge
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Point
Not confident/locally
Guidance on what data
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Diffuse
Guidance on what data
More confident of significant input and ability to predict
Regulation on the edge
Last gasp
Range of scenarios
Screening process
Decision free
Start with data, cost-benefit.
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Lack of published research. Quantifying and capacity
Prioritise industries and pollutants on basis.
Developing conceptual models. Flow/linking to ?
Temporal change need for 3d-4d
Go for high flow: how to find? attenuation in these places
Attenuation of these places
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Isotopes
Scale relates to the question
Models - nests