Applications of Integrated Surface Water/Groundwater Modelling

Techniques and Perspectives

P.J. Thompson, M.A. Marchildon, E.J. Wexler, J.D.C. Kassenaar Earthfx Incorporated

GeoMontréal 2013

October 2, 2013

Introduction

…demonstrate that integrated modelling is a practical solution to complex water management problems…

Case Studies: 1. Large Scale Urban Development

2. Assessment of Municipal Well System in contact with nearby surface water features

3. Eco-hydrology study of linkages between groundwater recharge and significant surface water features

Ground water and Surface-water FLOW

GSFLOW: • Released in 2008 • Free and open source • Modular • Fully distributed • Based on the USGS PRMS and MODFLOW

(Markstrom et.al., 2008)

GSFLOW Submodels

Hydrology (PRMS) GW (MODFLOW-NWT) Hydraulics (SFR2)

GSFLOW: Multi-Resolution

Climate variables 10:1

Surface hydrology 1:1

Sub-surface 5:1 hydrogeology

Stream networks Treated as linear segments independent of grid resolution

( 5 - 200m )

( 10 - 50m )

( 2 - 4 km )

NEXRAD (U.S. Based Doppler Weather Radar) Click for Animation

Environment Canada (AES) Rain Gauges

NEXRAD (Buffalo, NY)

GSFLOW: High Resolution Land Use

Land Use Class Assigned to 20-m Grid

% Impervious Based on Land Use

Class

GSFLOW: Cascade flowpaths

• 5m LIDAR digital elevation

model down-scaled to a 10m DEM

• Flowpaths defined using an 8-directional, steepest decent algorithm

GSFLOW: Cascade flowpaths

• Runoff generated from one

grid cell can infiltrate in an adjacent cell (i.e., Run-on)

• Infiltration into the soil zone of one cell is routed to an adjacent cell (interflow) and can emerge as surface runoff (exfiltration)

• Timing is treated explicitly

• Assumption: water runs downhill

GSFLOW: Cascade flowpaths

Q

Q

“Nash (1957) cascade”

GSFLOW: Streamflow

• GSFLOW outputs total streamflow as opposed to cumulative baseflow

• Water budget calculated for each stream cell, reach, pond and lake

Click for Animation

GSFLOW: Calibration

Transient Groundwater Calibration to

Monitors

Transient Surface Water Calibration to Stream Flow Gauges

Case Study 1: Large Scale Urban Development

• Large urban development in Central Florida

• 1100 km2 Area

• Model centered on wetland complex over karst

Caloosahatchee River

Telegraph Swamp

Proposed Site

Case Study 1: Large Scale Urban Development

• Complex stormwater management plan

• Compare Current and Post-development conditions

• Analyze changes to groundwater recharge, runoff, and wetland hydroperiod

• Demonstrate that the storm water management system will restore more “natural” conditions

Proposed Site Plan

Case Study 1: Large Scale Urban Development

• Transient Model Results

• Current conditions

• Precipitation

• Groundwater heads

• Streamflow

• Lake & Wetland Stage

Click for Animation

Case Study 1: Large Scale Urban Development

• Simulated Wetland Hydroperiod

• Current conditions

• Range between 0-365 days

• Magenta areas are wet 365 days

Case Study 1: Large Scale Urban Development

• Natural stream network

• No ditching

• Pre-Columbian vegetation and land use estimated from historical mapping and photography

Case Study 1: Large Scale Urban Development

• Simulated Change in Infiltration

• Natural to Current Conditions

• (decrease/

increase)

Case Study 1: Large Scale Urban Development

Current Simulated Hydroperiods

Post-Development Simulated Hydroperiods

Case Study 1: Large Scale Urban Development

Natural, Post-development, and Current Conditions

• Wetland Stage

Case Study 2: Wellfield Interactions with SW

• Study conducted for Conservation Halton

• Municipal well field supplies Milton, Ontario, Canada’s fastest growing city

• Complex reservoir operations

• Several large quarries above the escarpment

Case Study 2: Wellfield Interactions with SW

• Groundwater model layers follow stratigraphy

• Layers adjusted to preserve continuity

Wellfields

Case Study 2: Wellfield Interactions with SW

• Runoff directed to lakes and streams, flow routed down stream network

• Groundwater leaks in/out of lake cell and stream segment depending on stage and aquifer head

• Total streamflow is simulated

Case Study 2: Wellfield Interactions with SW

OBSERVED PREDICTED

Simulated Stage in Reservoirs

Kelso Lake

Hilton Falls

Kelso Reservoir Control Structure (Hatch, 2007)

Case Study 2: Wellfield Interactions with SW

• Had difficulty matching seasonality in the wellfield

• Required two-stage lake leakage: Enhanced leakage around shoreline when filled

• Lower lake bottom leakage is reduced by silts and fine sediments

Upper Lake: Summer high stage Lower lake: Winter holding level

Lake Leakage Out Lake Leakage In

Case Study 2: Wellfield Interactions with SW

OBSERVED PREDICTED Campbellville – MW2/05B

Kelso TW3/67

Kelso TW4/67

Shows influence of high leakage from lake at summer stage Heads in Wellfield Monitors

Case Study 3: Ecohydrology Recharge Assessment

• Study conducted for Lake Simcoe Region Conservation Authority

• Detailed assessment of the linkages between recharge and significant surface water features

• Drought assessment

• Model includes all 1st Order Streams

• 85 Lakes, Ponds, and Lake/Wetlands

Case Study 3: Ecohydrology Recharge Assessment

Backward Particle Tracking from Features of Interest to Areas of

Recharge

See Marchildon et al. in the proceedings for a more detail discussion

Stream: Orange pathlines Wetland: Green pathlines

In Summary

• Integrated modelling is rapidly becoming an accepted strategy to assess complex challenging problems

• Integrated models can assess practical problems

• GSFLOW represents a practical, scalable tool, capable of solving real-world engineering problems

• Demonstrated application in multidisciplinary projects

Thanks to:

Questions? Click for Animation

Simulated heads and lake stage at Kelso Reservoir Dry year (2007) and wet year (2008)