Simulating hydrologic and biologic
response to land use and climate
change
Trout Lake
Black Earth
Randy Hunt, John Walker, Jeff Steuer (and Steve Westenbroek)
USGS WRD, Middleton, WI
Coupled ground water / surface water model
USGS OGW; publication date: Feb 29, 2008
http://pubs.usgs.gov/tm/tm6d1/
GSFLOW—Coupled Ground-Water and SurfaceWater Flow Model based on the Integration of the
Precipitation-Runoff Modeling System (PRMS) and
the Modular Ground-Water Flow Model
(MODFLOW-2005)
By Steven L. Markstrom, Richard G. Niswonger, R.
Steven Regan, David E. Prudic, and Paul M. Barlow
Chapter 1 of
1
Linking PRMS to MODFLOW
Precipitation is partitioned between
evapotranspiration, runoff, infiltration, and
storage by balancing daily energy and mass
budgets of the snowpack, soil zone, and
unsaturated zone.
Instead of applying recharge,
ET, and runoff, as boundary conditions input into the
model, they are simulated.
Why would you do this to yourself?
•  Cons
–  Different temporal
scales
–  Different discretization
paradigms
–  Different observation
and parameter issues
–  More complexity
–  Runtimes are much
longer
•  Pros
–  GCM outputs are temp
and precip, they aren t
recharge arrays and gw
sink coefficients
–  Land-use questions can
involve both sw and gw
–  The world is coupled,
you re fooling yourself
by not doing it
A litmus test for our understanding (or, no place to hide)
2
Part I: Coupled Groundwater/Surfacewater Models and Climate Change
USGS Trout Lake Water, Energy, and Biogeochemical Budgets
(TL-WEBB) Site Vilas County Wisconsin
Concept: Hydrologic Memory
snowpack
Same parameter set – different
result based on spin up length!
Seepage lake stage
Early time (11 yr spin up)
Late time (7 yrs)
3
Surface water and Groundwater models of the USGS Trout Lake Water, Energy, and Biogeochemical Budgets (TL-WEBB) Site
PRMS HRU
map
heads
streamflows
MODFLOW
model
Stevenson
Ck
Trout
Trout
Lake
Lake
N
0
4
6 km
142 Hydrologic Response Units
Glaciated outwash area with immature drainage
Dense lake district
Low topographic relief
Strong gw-sw interaction
•
•
•
•
•
Top Elevation (UZ
range = 0 to 50 m)
30 LAK lakes
20 SFR stream segments
230 rows x 240 columns
6 layers, 220800 nodes
Inset from regional analytic element model
Stevenson Creek GSFLOW Model (northern WI)
16,000
streamflow (cubic m per day)
•
•
•
•
•
2
lakes
14,000
12,000
Basecase
+4.4 degrees C
10,000
8,000
6,000
4,000
2,000
0
7/27/05
8/10/05
8/24/05
9/7/05
9/21/05
Date
dry
4
There are very few studies that have linked the
abiotic effects that hydrologists know well to the
ecological community that the public holds dear.
Without understanding the ecohydrology, we will
never truly answer these important societal
questions.
Ground Water 41(3):289
Macroinvertebrate abundance (individuals per sample)
450
400
350
300
250
North
200
(WGD)
Stevenson
150
(GR)
100
2
4
6
8
10
Low pulse frequency, counts
Hydrograph shape metric
Allequash
(HGD)
Trout
Lake
Abundance (individuals per sample)
e.g., Olden and Poff (2003)
400
350
basecase
300
N
+4.4 deg C
250
200
Modified from Hunt, R.J., Strand, M., and Walker, J.F., 2006, Measuring groundwatersurface water interaction and its effect on wetland stream benthic productivity, Trout
Lake watershed, northern Wisconsin, USA. Journal of Hydrology 320(3-4):370-384.
150
100
50
0
Allequash (HGD)
North (WGD)
Stevenson (GR)
0
2
4
8 Kilometers
5
Part II: Coupled Groundwater/Surface-water
Models and Land-use Change (urbanization)
No change
in climate
driver
Because we
have sw and a
gw model…
Hunt and Steuer (2001)
Part II: Coupled Groundwater/Surface-water
Models and Land-use Change (biofuels)
Black Earth Creek GSFLOW Model
BEC
GW model
extent
Dane County
GW regional
model
extent
Pumping
well
6
flood
BEC surface-watershed
Bla
ck
Ea
rth
C
ree
k
Dane County line
baseflow
Why are these
areas in model
domain?!
BEC groundwater
contributing area
What are some potential
outcomes of increases
in biofuel production?
• An increase in demand
for fuel stocks (e.g.,
corn, switchgrass)
• Higher prices
• Economic payments
from fallow land
programs (e.g., CRP)
less lucrative
Active Ag 10 to 20 times
lower than CRP
• Interest in conversion of
CRP back to crops
Steuer and Hunt (2001)
7
Mazomanie
flood
Cross
Plains
Black Earth Ck
urban area of Hunt and
Steuer (2001)
Middleton
(urban)
Return of the Shape Metrics, this time flood related…
(Olden and Poff 2003)
Flood size (3X and 7X
median daily flow)
Mean high flow
events per year
Flood size (75th
percentile)
In an area already troubled with flooding, potential to: Increase
the amount of flood size, and increase the times per year it occurs
8
Hypothetical
Ethanol Plant well
535 gpm
from stream
from other
muni well
baseflow
Black Earth Cr
Double whammy? Ethanol Plant nr population center/trout water
Q = 675 gpm (1 million gal/day) from Upper Aquifer
332 gpm
from stream
from other
muni well
baseflow
Black Earth Cr
Ethanol Plant near population center and trout water
Q = 1 million gal/day from Upper+Lower Aquifer
9
Hypothetical
Ethanol Plant well
flooding
Ethanol Plant downstream farther from population center
but farther from trout water
Q = 1 million gal/day from Upper Aquifer
The Upshot #1
Focusing on right tool for the right job
–  GCMs put out precip and temp, if not this what?
–  Skepticism: gw models reporting sw impacts and sw
models doing gw impacts (need coupled model)
–  Climate change can be expected to influence
hydroecology
–  Land use change can also be expected to influence
hydroecology, especially when all impacts included
10
The Upshot #2
Where/how water use occurs can mitigate
impact
–  Withdrawals form a new basement for water
levels and flows (regardless of natural variability)
–  But we have potential to influence what the resulting
basement is because it is possible to distribute/
spread adverse effects of withdrawals
–  One possible hopeful view for the future: with
planning the footprint of biofuels production on
water resources can be reduced
11
Runtime Trauma!
F ollow S equence of F igure 10
F ollow S equence of F igure 5
MO D F L O W-­‐only
steady-state =
seconds to run
transient =
seconds to run
P R MS -­‐only
Integrated s imulation
R un G S F L O W
D eclare and Initializ e (s tep 1)
Allocate and R ead (s tep 2)
C heck for New S tres s
R ead and P repare (s tep 4)
R un S teady S tate (s tep 4)
P R MS L and S urface (s tep 5)
Iteration L oop (s tep 6)
P R MS S oil Mois ture (s tep 7)
Iteration L oop
Black Earth Creek =
2 days for 22-yr
simulation
D aily Time L oop (s tep 3)
Time-­‐s tep loop
Fully coupled:
Trout Lake = 7-14 hrs
for 15-yr simulation
…not so good for lots
of parameters…
Add flows from P R MS to
MO D F L O W (s tep 8)
MO D F L O W formulate
(s teps 9 and 10)
Add flows from MO D F L O W
to P R MS (s tep 11)
C heck for convergence
(s tep 12)
P R MS and MO D F L O W
budget (s tep 13)
O utput
C lean and deallocate (s tep 15)
12
macroinvertebrate
abundance
450
# of individuals
400
x ± 1SE
350
North
300
(WGD)
250
Stevenson
200
(GR)
150
100
Allequash
50
0
HGD site WGD site
GR site
(HGD)
Trout
Lake
macroinvertebrate
richness
# of taxa per sample
14
12
N
x ± 1SE
10
8
6
Hunt, R.J., Strand, M., and Walker, J.F., 2006, Measuring
groundwater-surface water interaction and its effect on wetland
stream benthic productivity, Trout Lake watershed, northern
Wisconsin, USA. Journal of Hydrology 320(3-4):370-384.
4
2
0
0
2
4
8 Kilometers
HGD site WGD site GR site
13