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Quantitative approaches to understanding groundwater and surface water availability in the Twin Cities Metropolitan area:
Metro Model 3 and WEAP
Evan Christianson (Barr Engineering) and Ailsa McCulloch (Stantec Consulting)
Overview
• Introduction– Groundwater – surface water review– Minnesota’s water context (availability, water
law, tools)– Quantitative modeling as a decision support tool
• Case study 1: Metro Model 3 (Twin Cities)• Case study 2: WEAP Water Allocation Model (CA)• Applicability to Minnesota
Overview
• Introduction– Groundwater – surface water review– Minnesota’s water context (availability, water
law, tools)– Quantitative modeling as a decision support tool
•••
Groundwater and Surface Water Interaction
Discharge lake/wetlandGraining Stream
Flow-through lake/wetland
Recharge lake/wetlandLosing Stream
Disconnected withshallow water table
Disconnected withdeep water table
Groundwater “Capture”
Capture = increased recharge and/or decrease in groundwater discharge
Time scale depends on characteristics of aquifer and distance of well from water body
(Days to Decades to Centuries)
GroundwaterVolume 52, Issue S1, pages 100-111, 28 MAY 2014 DOI: 10.1111/gwat.12204http://onlinelibrary.wiley.com/doi/10.1111/gwat.12204/full#gwat12204-fig-0001
Metro-Wide Thought Experiment
Go from no-pumping to current conditionsHow long for changes in baseflow to equilibrate?
Current Pumping
Time to obtain equilibrium,
steady-state condition
No Pumping
Perc
ent R
educ
tion
in T
otal
R
egio
nal B
asef
low
Years
Drawdown in Jordan Aquifer Near Pumping Well
Rapid response in source aquifer near pumping wellLess than 2 days to get over 90% steady-state drawdown
Steady-State Equilibrium
Drawdown at Water Table Near Pumping Well
Slow Response at Water Table
Steady-State Equilibrium
84% of steady-state drawdownafter 10 years
Potential Vulnerability of Surface-Water Features to Groundwater Pumping
The picture can't be displayed.
Available data indicate likely not vulnerable to pumpingAvailable data indicates potentially vulnerable to pumpingPotentially vulnerable with wide littoral zone
Barr Engineering for Metropolitan Council, 2011
Overview
• Introduction– Groundwater – surface water review– Minnesota’s water context (availability, water
law, tools)– Quantitative modeling as a decision support tool
•••
Minnesota Groundwater Recharge
Smith and Westenbroek, 2015
Minnesota Groundwater Recharge
1
2
3
4
5
0
Avg. Infiltration(in/month)
Barr Engineering for Metropolitan Council, 2014
Introduction:
Water Rights Overview
The Hydrologic Significance of the 100th Meridian
Introduction:
Water Rights Overview
The Hydrologic Significance of the 100th Meridian
Sanford and Selnick, 2013. JAWRA Vol 49, No. 1
Introduction:
Water Rights Overview
…and the Implication for water rights in the U.S.
Minnesota Water Priority Classes
• Minnesota has a riparian water law system. • Lakes, streams, and groundwater = “Waters of the
State” • New permit applicants have same priority as existing
permit holders, assuming water is for the same purpose
• If a conflict exists, water users have the opportunity to develop a plan for proportionate distribution of limited water available among all users in the same priority class.
Minnesota Water Use Priority Classes1.) Municipal water supply and power production with contingency plan2.) < 10,000 gallons per day3.) Agriculture irrigation and agriculture processing4.) Power production in excess of contingency plan5.) Other > 10,000 gal/day6.) nonessential uses
Groundwater Appropriations and Relationship to Surface Waters
Groundwater appropriations that will have potential impacts negative impacts to surface waters are subject to applicable provisions in section 103G.285
What is a negative impact?
MN Section 103G.287
Subd 1 - DNR Commissioner may waive a requirementSubd 2 - Limited consumptive use during periods of low flow
Subd 3 - Protective elevations on surface waters (>500 acres)Aquatic VegetationExisting UseTotal volume and slope of littoral zone
Subd 4 – Support of property owners (< 500 acres)Subd 5 - Extra restrictions on trout streamsSubd 6 - Contingency Planning
Impact to Surface Water Thresholds
Report to the Minnesota State Legislature: Definitions and Thresholds for Negative Impacts to Surface Waters, January 2016
Streams • Diversion limit of no more than 10% of the August median base flow
Lakes• with constant stream outflow = apply stream threshold• without constant stream outflow = protection elevation• Goal is to maintain characteristic hydrology, ecology, and riparian uses of
the lake most of the time
Wetlands• Currently proposing establishing target hydrographs for various wetland
types• Currently very limited wetland-related hydrologic data
Effect on Permitting Process
1.) Establish negative impact thresholds for surface water
bodies
2.) Establish sustainable diversion limits that will maintain
protected flows and protection elevations for those water bodies
3.) Conduct groundwater modeling to determine the effects of
groundwater withdrawals on the surface water bodies
4.) Assess to what degree individual groundwater withdrawals
may need to be adjusted.
Effect on Permitting Process
Effect on Permitting Process
Effect on Permitting Process
September 26, 2018
Barr Engineering, 2012
Effect on Permitting Process
Effect on Permitting Process
1
2
3
4
6
5
1. Straight River GMA2. Bonanza Valley GMA3. NE Metro GMA4. Little Rock Creek5. Cold Spring6. Rochester
Introduction:
Background in Modeling
Metro Model 3
• 11- County Metro Area• All major aquifers and aquitards• All high capacity pumping • Soil Water Balance recharge
model• land use, topography, daily
climate, soils, etc..• Calibrated to > 80,000
observations• Hydraulic head, baseflow,
transmissivity, etc.
Metro Model 3Model Row 267
A A’McLeod Co. Scott Co. Dakota Co.Carver Co.
Quaternary Sediments
Jordan Sandstone
St. Lawrence Formation
Tunnel City Group
Wonewoc SandstoneEau Claire Formation
Mt Simon – Hinckley Sandstone
Cretaceous and Paleozoic sandstone and siltstone St. Peter SandstonePrairie du Chien Group
Vertical exaggeration ~ 150x
faul
t
faul
t
faul
t
faul
t
Metro Model 3
Surface Water Boundary Conditions
Negative (purple) indicates flux out of modelPositive (green) indicates flux into model
Cubic Meters Per Day
Metro Pumping Optimization
• Distribute pumping to maximize total groundwater withdrawals while not exceeding pre-determined threshold (sustainability constraints)
Metro Pumping Optimization
Fens – No more than 1 foot of drawdown
Trout Streams – No more than 10% change in flux between surface water and groundwater
Mississippi River – No more than 25% change in flux between surface water and groundwater
All other surface water bodies – No more than 15% change in flux between surface water and groundwater
Metro Pumping Optimization -Constraints
Constraint Type Threshold NumberDrawdown from available head for confined bedrock aquifers above the Mt. Simon-Hinckley 50% 2955
Drawdown in the Mt. Simon-Hinckley aquifer 1 foot 1897Drawdown at Calcareous fens 1 foot 6Change in net baseflow to trout streams -10% 13 reachesChange in net baseflow to other river reaches -15% 67 reachesChange in net baseflow to the Mississippi River -25% 12 reaches
Change in net groundwater flux for high and outstanding biodiversity -15% 108 areas
Change in net groundwater flux to potentially vulnerable lakes with wide littoral zone -10% 68
Change in net groundwater flux for remaining lakes at grouped by Township -15% 103
Change in flow directions at site of groundwater contamination 10 degrees 8Total 5237Direction
Metro Pumping Optimization -Wells
n = 2074
Metro Pumping Optimization -Results
Mill
ion
Gal
lons
per
Day
Time Groundwater/Surface-water understandingDefinition of sustainabilityTechnological advancement
USGS &Met Council
(1973)
Recent
Schoenberg(1990)
Metro Pumping Optimization –Binding Constraints
Tow
nshi
p R
ange
La
kes/
Wet
land
s
Stre
ams
and
Riv
ers
Vuln
erab
le
Basi
ns
Biod
iver
sity
Area
s
Trou
t Stre
ams
Safe
Yie
ld
Hyd
raul
ic H
ead
Fens
Flow
Dire
ctio
n
Mt.
Sim
onH
ydra
ulic
Hea
d
AverageBinding Constraint
Overview
•––
•• Case study 2: WEAP Water Allocation Model (CA)•
Case Study 2: WEAP Water Allocation Model For the CA State Water Resources Control Board
• Development in desert environments• Urban stressors
– 39 million people– Large population centers: SF Bay Area, LA
• Agricultural stressors– 6 million acres irrigated farmland– $46 billion/yr exports
• $2.2 trillion economy• Droughts• Spatial challenges with precipitation• Water rights challenges
The Need for Water Allocation Models
+
Complex, Artificial Water System
Complex, Artificial Water System
• Development in desert environments• Urban stressors
– 39 million people– Large population centers: SF Bay Area, LA
• Agricultural stressors– 6 million acres irrigated farmland– $46 billion/yr exports
• $2.2 trillion economy• Droughts• Spatial challenges with precipitation• Water rights challenges
The Need for Water Allocation Models
+
Complex, Artificial Water System
Complexity of System
Complexity of System
Water Agencies in CA
– Drought– Flood control– State Water Project
• 34 storage facilities• 20 pumping plants• ~700 miles of open
canals/pipelines
– Allocates water rights• Surface Water• Groundwater
– Water quality• Contaminants• Instream Flow Requirements
Water Rights Databases
Mixed Riparian/Prior Appropriation
Riparian
eWRIMS MPARS
The Problem
The Problem
Water Balance:Why it is so important to understand
Supply • Rivers and Streams• Canals• ReservoirsDemand • Urban Demands• Agricultural Demands• Ecological/Instream Flow
RequirementsWater RightsSystem Operations
Overview
•––
••• Applicability to Minnesota
Water Balance:Why it is so Important to understand
Applicability to Minnesota
+
Applicability to Minnesota
