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(*)(

dzdhSeKq

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

hh 1

1))*(1(

)(

rs

re

hS

)(

21

1)1/(0 ))1(1(**)( nnn

eLee SSKSK

Results

StationPrecip.

(P)Drainage

(D) D/P AquiferPrior 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-

Simpson12-14 Fairchild et al. (1990)

Christenson et al. (2011)Shawnee 864 28 3.2 Garber-

Wellington5-10 Wood and Burton (1968)

Carr and Marcher (1977)Spencer 895 108 12 Garber-

Wellington5-10 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

)

10/1/2006

10/11/2006

10/21/2006

10/31/2006

11/10/2006

11/20/2006

11/30/2006

12/10/2006

12/20/2006

12/30/2006

1/9/2007

1/19/2

007

1/29/2007

2/8/2007

2/18/2007

2/28/2

007

3/10/2

007

3/20/2

007

3/30/2

007

4/9/2007

4/19/2

007

4/29/2

007

5/9/2007

5/19/2007

5/29/2

007

6/8/2007

6/18/2

007

6/28/2007

7/8/2007

7/18/2

007

7/28/2

007

8/7/2007

8/17/2007

8/27/2

007

9/6/2007

9/16/2

007

9/26/2007

0

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