Comparative Review Integrated Models
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Transcript of Comparative Review Integrated Models
Comparative Review of Integrated Groundwater and Surface Water Models
June 21, 2011
Acknowledgements
Ontario Ministry of Natural Resources Mike Garraway Lynne Milford
DHI Water and Environment Patrick Delaney Ying Qiao Doug Graham
Alberta Innovates Dr. Jon Paul Jones
S.S. Papadopulos and Associates Chris Neville
AquaResource Inc. David Van Vliet Steven Murray Christian Gabriel
Comparative Review of Integrated Groundwater and Surface Water Models
Prepared by:AquaResource Inc.DHI Water and EnvironmentAlberta InnovatesS.S. Papadopulos and Associates
Prepared for: The Ontario Ministry of Natural Resources
Summary of Report• Compare available
codes based on theory, numerical methods, and user experience
• GSFLOW*• HydroGeoSphere*• MikeSHE**• ModHMS• Parflow
• Ontario case studies. * Subwatershed 19 (Credit River)** Mill Creek Subwatershed (Grand River)
• Recommended modelling methods and procedures
• Release Summer 2011
Conjunctive Modelling – Why? Conventional surface water or
groundwater models don’t always reflect natural systems Simplifying assumptions made for either
groundwater or surface water portions of model.
Interpretation and quantification of interaction between surface water and groundwater system difficult.
The value of conventional models is reflected by the hydrological processes represented by those models
Traditional methods are not well suited to cumulative impact assessment. Unless physical processes are not well represented, marginal and incremental change prediction is uncertain
Conjunctive Models Considered
Model Developer Hydrologic Processes
GSFLOW (MODFLOW + PRMS)
United States Geological Survey
Physical & Empirical,Semi-distributed
Hydrogeosphere (HGS)
University of Waterloo and
Laval University
Physical,Fully Distributed
MIKE SHE DHI Water & Environment
Physical and EmpiricalFully or semi-distributed
Model Evaluation GSFLOW (USGS) Based on well
established and accepted modelling codes (PRMS + MODFLOW)
Supported by USGS Open source, free No dynamic stream
routing, no overland flow routing
Soil water balance and runoff calculations highly empirical
Daily timesteps
Model Evaluation – HydroGeoSphere (HGS) (University of Waterloo)
Variable finite element mesh resolution, excellent mass balance
Sophisticated subsurface model: 3D Richards representation
of unsaturated zone. Variable saturated
groundwater flow as well as Limited hydrologic processes
(snowmelt, soil water balance, interflow)
long run times
Model Evaluation – MIKE SHE (DHI Water and Environment)
Highly flexible, full GUI interface
Empirical and physical representations of hydrologic processes
Sophisticated post processing
Reasonable run times DHI support Uniform finite difference
mesh
Examples of Model Comparison Criteria
Watershed
Processes
•Rainfall
•Snowmelt
•ET•Overland Flow
•Seasonal Parameters
Vadose Zone
•Soil Moisture•Infiltration, Percolation, Recharge
Groundwater
•Lumped vs numerical
•Boundary conditions
•Fractures
•Macropores
•Water takings
Surface Water
•Channel flow
•Pipe flow
•Lakes
•Flooding
•Dams and reservoirs
•Diversions
•Irrigation
•Erosion and Sediment
•Water takings
Other
•Numerical solution parameters•GIS support•GUI•Tech support•Training
Mill CreekGrand River Watershed
Subwatershed 19Credit River Watershed
Case Studies Objectives
Compare models Explore and demonstrate benefits of integrated models over
traditional approaches Develop recommended practices and methods
Case Study: Credit Valley Subcatchment 19
Case Study: Credit Valley Subcatchment 19 Headwaters of the Credit River - Approximately 60 km2 Land use: urban, agriculture, wetlands, aggregate. Issues:
Municipal drinking water supply (groundwater) Wastewater assimilation Streamflow quality and quantity
Existing studies: Subwatershed Study (CVC) Tier Three Water Quantity Risk Assessment (MNR, municipalities) Island Lake Water Budget Study
Existing Models HSPF, GAWSER (Surface Water) MODFLOW, FEFLOW (Groundwater)
Integrated Models Provide Realistic ET Predictions
Groundwater Recharge Predictions Influenced by Soils, Vegetation, Topography, Discharge
Groundwater Discharge Into Wetlands Simulated Without Boundary Conditions
Streamflow Impact Assessment
0.01
0.10
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Flow
(m3 /
s)
Month
Flow Distribution for Lower Monora Creek - MIKE-SHEBaseline vs Combined Impact Scenario
Pre-Impact Interquartile Range Post-Impact Interquartile Range Upper/Lower DecilePre-Impact Median Flow Post-Impact Median Flow
Mill Creek Subwatershed
Description of the Subwatershed Covers an area of roughly 100 km2 and is situated
between the Galt-Paris moraines. The headwaters of Mill Creek are located southeast of
Guelph, where Mill Creek flows southwest, joining the Grand River in downtown Cambridge (Galt).
Land cover within Mill Creek is predominantly agriculture, with forests and wetlands comprising the majority of the remaining land area.
Mill Creek supports cold-water fisheries, rich wetlands, and also has extensive aggregate production facilities within the watershed.
Mill Creek Subwatershed Land Cover
Calibration – Mike SHE Represents Low Flows Very Well. GW/SW Interactions Critical
01-Jan-04 01-Mar-04 01-May-04 01-Jul-04 01-Sep-04 01-Nov-040
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Simulated Discharge Observed Discharge
Dis
charg
e (
m3/s
)
Variable ET Across Watershed, Influenced by Landuse, Wetlands, Aggregate Extraction
Groundwater Discharge Critical Along Streams, Wetlands and Hillslopes
Simulated Soil Moisture Reflects Delineated Wetlands
Seasonal Soil Moisture Variability in Wetlands
Conclusions Benefits of Integrated Models over Traditional Models
Integrating groundwater and surface water models removes traditional assumptions (recharge, boundary conditions)
Realistic water budgets (ET, Influence of Topography) Groundwater / surface water interactions (Wetlands, Hillslopes, Hummocky Areas)
better handled Physically-based continuous low flow predictions – needed for ecological flow
assessments Data requirements are similar to traditional approaches
Limitations Computational Time – It can be manageable Calibration Time – Reduced with experience Urban Systems – Manage technical expectations Learning Curve – Training requirements are significant
Success requires both surface water and groundwater modelling expertise Costs are marginally extra than traditional methods but the results are much
more meaningful