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Estimating Groundwater Recharge Using the Oklahoma Mesonet
Sam WallaceUndergraduate, OSU Dept. Environmental Science
Dr. Tyson OchsnerAssistant Professor of Soil Physics, OSU Dept. Plant and Soil
Sciences
Source: Oklahoma Water Atlas, 1983
Groundwater Monitoring
• USGS monitoring wells/streamflow gauges– Real-time monitoring wells– Daily groundwater monitoring– Real-time stream flow gauges
• Water Table Fluctuation Method• Water Budget Method
Groundwater Recharge Evaluation through Soil Moisture
• Established statewide monitoring network• Long history of monitoring (since 1994)• Soil moisture monitoring at 5, 25, and 60 cm
Our Study
• Five Mesonet stations: Acme, El Reno, Fittstown, Shawnee, Spencer
• Chosen for availability of both soil moisture sensors and groundwater wells.
Methods• Mesonet temperature
reference values converted to matric potential
• Soil hydraulic parameters calculated using ROSETTA
Source: Illston et al., 2008
Methods• Volumetric Water Content
• Effective Saturation
• Hydraulic Conductivity
• Buckingham-Darcy Equation
)1(*)( dz
dhSeKq
Where:•q= water flux- groundwater recharge•K(Se)= hydraulic conductivity•Se= water content•h= matric potential•z= depth•θ(h) = volumetric water content θr = residual water contentθs =saturated water contentα = fitting parameter n = a measure of the pore-size distribution •K0 = a fitting matching point at saturation •L = empirical parameter
nn
rsr
h
h1
1))*(1(
)(
rs
re
hS
)(
21
1)1/(0 ))1(1(**)( nnn
eLee SSKSK
Results
StationPrecip.
(P)Drainage
(D) D/PAquifer
Prior R/P Reference
mm mm % %
Acme 768 77 10 Rush Springs 10 Tanaka and Davis (1963)
El Reno 817 42 5.1 N. Canadian 4.7 Daniel (1999)
Fittstown 917 97 11 Arbuckle-Simpson
12-14 Fairchild et al. (1990)Christenson et al. (2011)
Shawnee 864 28 3.2 Garber-Wellington
5-10 Wood and Burton (1968)Carr and Marcher (1977)
Spencer 895 108 12 Garber-Wellington
5-10 Wood and Burton (1968)Carr and Marcher (1977)
Mean 852 70 8.3 8.5
Table 1: Mean annual precipitation (P), drainage at 60 cm (D), and the ratio D/P for five Mesonet stations using data from 1999 through 2011. For comparison, prior estimates of the ratio of groundwater recharge (R) to P are also shown.
Results
00.10.20.30.40.50.60.70.8
-45.00
-44.50
-44.00
-43.50
-43.00
ACME Groundwater Recharge and Mean Daily Groundwater Well Levels for the 2005 Water Year
Daily
Dra
inag
e (m
m)
Mea
n Da
ily D
epth
to W
ater
Tab
le (ft
)
10/1/2
006
10/11/2
006
10/21/2
006
10/31/2
006
11/10/2
006
11/20/2
006
11/30/2
006
12/10/2
006
12/20/2
006
12/30/2
006
1/9/2
007
1/19/2
007
1/29/2
007
2/8/2
007
2/18/2
007
2/28/2
007
3/10/2
007
3/20/2
007
3/30/2
007
4/9/2
007
4/19/2
007
4/29/2
007
5/9/2
007
5/19/2
007
5/29/2
007
6/8/2
007
6/18/2
007
6/28/2
007
7/8/2
007
7/18/2
007
7/28/2
007
8/7/2
007
8/17/2
007
8/27/2
007
9/6/2
007
9/16/2
007
9/26/2
0070
0.1
0.2
0.3
0.4
0.5
0.6
0.7
-140.0
-120.0
-100.0
-80.0
-60.0
-40.0
-20.0
0.0
FITT Groundwater Recharge and Mean Daily Groundwater Well Levels for the 2007 Water Year
Daily
Dra
inag
e (m
m)
Mea
n Da
ily D
epth
to W
ater
Tab
le (ft
)
Discussion
• Limitations in this new method– No upward water flow– Time lag varies with site, weather
• Promising results– Comparable to historical averages– Calculated drainage events
correspond to observed water table rises
• As always, further research needed– Does this method work in the
extremes of the state?– Mechanics of time lag
Source: Wikimedia
AcknowledgementsI would like to thank the following sponsors:•Oklahoma State University Freshman Research Scholars Program•Oklahoma State University Wentz Research Project•EPA Greater Research Opportunities for Undergraduates Fellowship