U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2015–5183

Version 1.1, February 2016

Prepared in cooperation with the Oklahoma Water Resources Board

Hydrogeological Framework, Numerical Simulation of 

Groundwater Flow, and Effects of Projected Water Use 

and Drought for the Beaver-North Canadian River Alluvial 

Aquifer, Northwestern Oklahoma

OKLAHOMA

Area enlarged

Beaver-North Canadian River

alluvial aquifer
Front cover:

Top, Canton Lake. Photo by Kevin Smith, U.S. Geological Survey Oklahoma Water Science Center.

Bottom, Canton Lake. Photo by Derek Ryter, U.S. Geological Survey Oklahoma Water Science Center.

Back cover:

Top, Photo by Kevin Smith, U.S. Geological Survey Oklahoma Water Science Center.

Bottom, Photo by Kevin Smith, U.S. Geological Survey Oklahoma Water Science Center.
Hydrogeological Framework, Numerical 

Simulation of Groundwater Flow, and 

Effects of Projected Water Use and 

Drought for the Beaver-North Canadian 

River Alluvial Aquifer, Northwestern 

Oklahoma

By Derek W. Ryter and Jessica S. Correll

Prepared in cooperation with the Oklahoma Water Resources Board

Scientific Investigations Report 2015–5183

Version 1.1, February 2016

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Director

U.S. Geological Survey, Reston, Virginia

First release: 2016

Revised: February 2016 (ver. 1.1)

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Suggested citation:

Ryter, D.W., and Correll, J.S., 2016, Hydrogeological framework, numerical simulation of groundwater flow, and 

effects of projected water use and drought for the Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma (ver. 1.1, February 2016): U.S. Geological Survey Scientific Investigations Report 2015–5183, 63 p.,

http://dx.doi.org/10.3133/sir20155183.

ISSN 2328-031X (print)

ISSN 2328-0328 (online)
iii

Acknowledgements

This study was conducted as part of the U.S. Geological Survey (USGS) Cooperative Water 

Program in cooperation with the Oklahoma Water Resources Board (OWRB). The authors thank 

the OWRB for support on this project and OWRB Water Resources geologist Christopher Neel 

for help with defining study objectives and providing hydrogeologic and water-use permit data. 

The authors thank USGS employees Shana Mashburn for help estimating aquifer hydraulic 

properties and Andrew Long and Bruce Campbell for providing constructive reviews of this 

work. The authors also thank former USGS employees Christopher Kunkel for help with the 

numerical simulations, analysis, and report editing; Noel Osborne for help with data collection 

and preliminary research; Logan Chatterton, Joseph Nadolsky, and Robert Frye for help with 

compiling tabular and geospatial datasets and building the numerical models; Trevor Grout 

for processing streamflow data and interpreting seepage-run results; and Matthew Collier for 

assisting with model analysis. 

v

Contents

Acknowledgements .....................................................................................................................................iii

Abstract ..........................................................................................................................................................1

Introduction ....................................................................................................................................................3

Purpose and Scope .............................................................................................................................3

Location and Description of Study Area ..........................................................................................3

Previous Investigations .......................................................................................................................5

Land Use and Population ....................................................................................................................5

Water Use and Management .............................................................................................................6

Hydrology .......................................................................................................................................................9

Climate ...................................................................................................................................................9

Streamflow Characteristics .............................................................................................................12

Hydrogeological Framework .....................................................................................................................15

Geology ................................................................................................................................................16

Hydrogeological Units .......................................................................................................................18

Potentiometric Surface and Water-Level Fluctuations ...............................................................18

Aquifer Hydraulic Properties ...........................................................................................................21

Conceptual Flow Model .............................................................................................................................25

Hydrological Boundaries ..................................................................................................................25

Stream Base Flow ..............................................................................................................................26

Reach I Seepage Runs .............................................................................................................26

Reach I Base-Flow Separation ...............................................................................................29

Reach II Seepage Run .............................................................................................................29

Groundwater Recharge ....................................................................................................................31

Soil-Water-Balance Model .....................................................................................................31

Local Recharge Estimation .....................................................................................................33

Woodward Site .................................................................................................................36

Seiling Site ........................................................................................................................36

Water Use ...........................................................................................................................................38

Evapotranspiration and Springs ......................................................................................................38

Conceptual Flow Model Water Budget ..........................................................................................39

Numerical Groundwater-Flow Model ......................................................................................................40

Assumptions .......................................................................................................................................40

Model Extents and Discretization ...................................................................................................40

Boundary Conditions .........................................................................................................................42

Model Calibration Methods .............................................................................................................44

Reach I Calibration Results ..............................................................................................................44

Reach II Calibration Results .............................................................................................................48

Model Sensitivity ................................................................................................................................50

Equal-Proportionate-Share Estimation ...................................................................................................50

Estimated Equal-Proportionate-Share Pumping in Reach I .......................................................51

Estimated Equal-Proportionate-Share Pumping in Reach II ......................................................52

Effects of Projected Water Use and Drought .........................................................................................53
vi

Projected Water Use .........................................................................................................................53

Prolonged Drought .............................................................................................................................53

Change in Groundwater Storage ...........................................................................................54

Effects of Drought on Streamflow and Lake Storage .........................................................54

Model Limitations ........................................................................................................................................57

Summary .......................................................................................................................................................58

References Cited .........................................................................................................................................61

Figures

1. Map showing locations of the Beaver-North Canadian River alluvial aquifer, 

reaches, hydrological features, observation wells, streamflow-gaging stations, 

and cities, northwestern Oklahoma ..........................................................................................4

2. Map showing irrigation and public water-supply wells and surface-water 

diversions active during 1980–2011 in areas overlying the Beaver-North Canadian 

River alluvial aquifer, northwestern Oklahoma .......................................................................7

3. Graphs showing total estimated annual groundwater use 1967–2011 by water 

demand category for A. Reach I and B. Reach II of the Beaver-North Canadian 

River alluvial aquifer, northwestern Oklahoma .......................................................................8

4. Pie charts showing distribution of mean annual groundwater use for 1967–2011 

by percentage for water-use categories for A. Reach I and B. Reach II of the 

Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma .........................10

5. Map showing interpolated mean annual precipitation and cooperative 

observer weather stations for the Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma, from daily weather-station data over the period 

1980–2011 ....................................................................................................................................11

6. Bar graph showing mean monthly precipitation at Woodward and Watonga, 

Oklahoma, weather stations for the period 1960–2012 ........................................................13

7. Graph showing annual departure from the mean annual precipitation from 

1908 to 2012 and 5-year weighted moving average for the Woodward weather 

station, Beaver-North Canadian River alluvial aquifer Reach I, northwestern 

Oklahoma ....................................................................................................................................13

8. Graph showing annual departure from the mean annual precipitation from 

1928 to 2013 and 5-year weighted moving average for the Watonga weather 

station, Beaver-North Canadian River alluvial aquifer Reach II, northwestern 

Oklahoma ....................................................................................................................................14

9. Graph showing median monthly streamflow for streamflow-gaging stations at 

Beaver River near Beaver, Oklahoma (07234000), at the North Canadian River 

at Woodward, Okla. (07237500), and at the North Canadian River near Seiling, 

Okla. (07238000), and the median monthly streamflow at the Seiling station 

for Reach I ...................................................................................................................................14

10. Graph showing median monthly streamflow at the North Canadian River below 

Weavers Creek near Watonga, Oklahoma (07239300), and near El Reno, Okla. 

(07239500), streamflow-gaging stations and the median daily streamflow at the 

El Reno station for Reach II ......................................................................................................15

11. Map showing the geology of the Beaver-North Canadian River alluvial aquifer 

area showing approximate delineation of bedrock units that underlie the 

aquifer ..........................................................................................................................................17
vii

12. Map showing the approximate thickness and altitude of the base of the 

Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma .........................19

13. Map showing the Beaver-North Canadian River alluvial aquifer potentiometric 

surface, direction of groundwater flow, and approximate depth to groundwater 

from observations in 2012 .........................................................................................................20

14. Graph showing long-term groundwater levels and trends from selected 

observation wells completed in the Beaver-North Canadian River alluvial 

aquifer, northwestern Oklahoma, 1980–2012 ........................................................................22

15. Map showing locations of published aquifer tests and calibrated horizontal 

hydraulic conductivity from numerical flow models for the Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma ...................................................23

16. Map showing streamflow measurements and calculated base flow from the 

1979 seepage run in Davis and Christenson (1981) for Reach I of the Beaver and 

North Canadian Rivers, northwestern Oklahoma .................................................................27

 17. Graph showing cumulative streamflow and streamflow corrected for tributary 

inflow with distance downstream from the upstream limit of the Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma, by stream reach in 

the Beaver and North Canadian Rivers, from the 1979 (Davis and Christenson, 

1981) and 2012 seepage runs ...................................................................................................28

18. Map showing streamflow measurements and calculated base flow from the 

2012 seepage run, Reach I of the Beaver and North Canadian Rivers, 

northwestern Oklahoma ...........................................................................................................30

19. Map of streamflow measurements and calculated base flow from the 1981 

seepage run for Reach II of the North Canadian River, from Christenson (1983) ...........32

20. Map showing mean annual groundwater recharge from 1980 to 2011 

calculated by using the soil-water-balance code of Westenbroek and others 

(2010) for the Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma ....................................................................................................................................34

21. Graph showing total annual groundwater recharge 1980–2011 calculated by 

using the soil-water-balance model for the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma ...............................................................................35

22. Graph showing sensitivity of recharge calculated by the soil-water-balance 

model for the Beaver-North Canadian alluvial aquifer to changes in precipitation 

and root-zone depth ..................................................................................................................35

23. Graph showing water-level fluctuation at observation well OW-4 and adjusted 

stream stage and precipitation at the North Canadian River at Woodward, 

Oklahoma (07237500), streamflow-gaging station ................................................................37

24. Graph showing water-level fluctuation at observation well OW-5 and stream 

stage and precipitation at the North Canadian River near Seiling, Oklahoma 

(07238000), streamflow-gaging station ...................................................................................38

25. Map showing Reach I and Reach II numerical groundwater-flow model layouts, 

active areas, and boundary condition cells excluding wells, Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma ...................................................41

26. Graph showing observed groundwater heads plotted with simulated heads 

combined for the steady-state and transient models for Reach I of the BeaverNorth Canadian River alluvial aquifer, northwestern Oklahoma .......................................44

27. Histogram showing head residual values combined for the steady-state and 

transient models for Reach I, Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma ...........................................................................................................45
viii

28. Map showing simulated potentiometric surface at the end of the transient 

simulation and head targets in Reach I symbolized by mean residual for the 

Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma .........................46

29. Graph of numerical groundwater-flow model mean annual flow budget for 

the period 1980–2011, Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma ...........................................................................................................48

30. Graph showing observed groundwater heads and simulated heads for Reach II 

of the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma ..............48

31. Graph showing distribution of head residuals combined for the steady-state 

and transient models for Reach II, Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma ...........................................................................................................48

32. Map showing simulated groundwater head and head targets symbolized by 

mean residual combined for the steady-state and transient models for Reach II 

of the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma ..............49

33. Graph of Reach I and Reach II numerical groundwater-flow model groundwaterhead sensitivity to changes in selected parameters, Beaver-North Canadian 

River alluvial aquifer, northwestern Oklahoma .....................................................................50

34. Graph showing percentage of Reach I of the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma, with less than 5 feet of saturated 

thickness after 20 years of various levels of continuous equal-proportionateshare groundwater pumping and scaled recharge .............................................................51

35. Graph showing percentage of Reach II of the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma, with less than 5 feet of saturated 

thickness after 20 years of various levels of continuous equal-proportionateshare groundwater pumping ...................................................................................................52

36. Graphs showing change in groundwater in aquifer storage in A. Reach I, and 

B. Reach II during a hypothetical severe 10-year drought for the Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma ...................................................55

37. Graph showing changes in streamflow at the North Canadian River near 

Seiling, Oklahoma (07238000), streamflow-gaging station during a hypothetical 

drought, 1994–2004. “Simulated streamflow” refers to the combined simulated 

base flow and other inflows such as lake streamflow releases .......................................56

38. Graph showing changes in streamflow at the North Canadian River near Yukon, 

Oklahoma (07239700), streamflow-gaging station during a hypothetical drought, 

1994–2004. “Simulated streamflow” refers to the combined simulated base flow 

and other inflows such as lake streamflow releases ..........................................................57

39. Graph showing simulated changes in Canton Lake water in storage during a 

hypothetical drought, 1994–2004 .............................................................................................58
ix

Tables

1. Summary statistics of groundwater use for selected periods for the BeaverNorth Canadian River alluvial aquifer ......................................................................................8

2. Estimated mean annual groundwater use for selected periods by use category 

in acre-feet, Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma ....................................................................................................................................10

3. Statistical summary of precipitation at selected weather stations for the 

Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma .........................12

4. Water-level depth statistics and water-level change from observation wells 

with multiple readings for the Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma ...........................................................................................................21

5. Estimated hydraulic conductivity and specific yield of the Beaver-North 

Canadian River alluvial aquifer from published aquifer tests ............................................24

6. Horizontal hydraulic conductivity assigned to textural classes of sediments in 

the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma ..................24

7. Texture and horizontal hydraulic conductivity assigned to bedrock units 

underlying the Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma ....................................................................................................................................25

8. Comparative streamflow statistics for selected U.S. Geological Survey 

streamflow-gaging stations during the 2012 seepage run, North Canadian River, 

northwestern Oklahoma ...........................................................................................................29

9. Conceptual flow model estimated annual hydrological budget for the BeaverNorth Canadian River alluvial aquifer, northwestern Oklahoma .......................................31

10. Statistical comparison of measured and simulated groundwater heads, 

numerical groundwater-flow model for the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma ...............................................................................47

11. Statistical summary for calibrated hydraulic conductivity and saturated 

thickness for the Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma ....................................................................................................................................47

12. Numerical groundwater-flow model mean annual flow budget, Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma ...................................................47

13. Equal-proportionate-share (EPS) pumping for Reach I and Reach II for select 

time periods, Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma ....................................................................................................................................52

14. Changes in water in storage after 50 years of groundwater pumping at the 2011 

rate and increasing the 2011 rate by 32 percent over a 50-year period for the 

Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma .........................53
x

Conversion Factors

Inch/Pound to International System of Units

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

Area

acre 4,047 square meter (m2)

acre 0.004047 square kilometer (km2)

square mile (mi2) 259.0 hectare (ha)

square mile (mi2) 2.590 square kilometer (km2) 

Volume

acre-foot (acre-ft) 1,233 cubic meter (m3)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

gallon per minute (gal/min) 0.06309 liter per second (L/s)

Hydraulic conductivity

foot per day (ft/d) 0.3048 meter per day (m/d)

Temperature in degrees Celsius (°C) may be converted to degrees Fahrenheit (°F) as follows:

°F=(1.8×°C)+32

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows:

°C=(°F-32)/1.8

Datum

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 

(NAVD 88).

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Altitude, as used in this report, refers to distance above the vertical datum.
xi

Abbreviations

BFI base-flow index, and a computer program that uses daily streamflow records with a 

hydrograph recession method to separate base flow from runoff

R2 coefficient of determination

DEM digital elevation model

EPS equal proportionate share

ET evapotranspiration

GHB general-head boundary

GPS Global Positioning System

Kh horizontal hydraulic conductivity

NLCD National Land Cover Database 

OCWP Oklahoma Comprehensive Water Plan

OWRB Oklahoma Water Resources Board

RMSE root-mean-square error

SWB soil-water balance

Sy specific yield

SFR2 Streamflow-Routing package version 2

USGS U.S. Geological Survey

WTF water-table fluctuation

Hydrogeological Framework, Numerical Simulation of 

Groundwater Flow, and Effects of Projected Water Use 

and Drought for the Beaver-North Canadian River Alluvial 

Aquifer, Northwestern Oklahoma

By Derek W. Ryter and Jessica S. Correll

Abstract 

This report describes a study of the hydrology, 

hydrogeological framework, numerical groundwater-flow 

models, and results of simulations of the effects of water 

use and drought for the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma. The purpose of the 

study was to provide analyses, including estimating equalproportionate-share (EPS) groundwater-pumping rates and the 

effects of projected water use and droughts, pertinent to water 

management of the Beaver-North Canadian River alluvial 

aquifer for the Oklahoma Water Resources Board. 

The Beaver-North Canadian River alluvial aquifer 

consists of unconsolidated sand, gravel, silt, and clay in 

varying proportions that underlies the Beaver and North 

Canadian River Valleys for approximately 175 miles (mi) from 

the Oklahoma Panhandle to the western edge of Oklahoma 

City in central Oklahoma. The aquifer as delineated for this 

study varies from 4 to 12 mi wide and is as thick as 308 feet 

(ft) in the northwest where the aquifer includes the Ogallala 

Formation. 

There are two distinct but in most areas hydraulically 

connected alluvial units that compose the Beaver-North 

Canadian River alluvial aquifer: a Quaternary-age 

topographically higher terrace deposit and a topographically 

lower, younger alluvium along the active river channel that 

includes active and Quaternary-age alluvium. The Beaver 

River composes the headwaters of the North Canadian 

River, which begins at the confluence of the Beaver River 

and Wolf Creek. The aquifer is divided for water management 

into two geographic areas: Reach I upstream from Canton 

Dam and Reach II downstream from Canton Dam. Reach 

I covers an area of approximately 874 square miles (mi2), 

and Reach II covers an area of approximately 371 mi2. The 

Beaver-North Canadian River alluvial aquifer crosses several 

climatic zones, from semiarid in the west to continental 

subhumid in the east. Mean annual precipitation varies from 

23.5 inches (in.) in the western part of this aquifer to 35.7 in. 

in the east.

Surface-water demands were met through numerous 

temporary and permanent surface-water diversions from 

the Beaver and North Canadian Rivers during the period of 

study. During the study period, seven diversions removed a 

mean annual 2,000 acre-feet (acre-ft) of water from Reach I. 

There were 14 diversions from Reach II with a mean annual 

permitted volume of approximately 81,000 acre-ft, including 

diversion into the Lake Hefner Canal for the Oklahoma 

City public water supply. During the period of this study, 17 

temporary surface-water diversion permits were active in 

Reach I, with total permitted volumes of 2,000 acre-ft, and 

41 diversions were active in Reach II, with total permitted 

volumes of 38,000 acre-ft. The total water use for each 

temporary permit was assumed to be taken over the 3-month 

period allotted to temporary withdrawal permits.

The groundwater-use analysis full period of record, 

1967–2011, was divided into two sub-intervals because of 

varying water use, 1970–80 and 1981–2011. Groundwater use 

in Reach I and Reach II was substantially greater from 1970 

to 1980 compared to the rest of the period, and the sub-period 

1981–2011 was used because this period includes recent 

population growth and modern irrigation methods. The total 

mean annual groundwater use in Reach I was 15,309 acrefeet per year (acre-ft/yr) during 1967–2011; 20,724 acre-ft/

yr during 1970–80, and 13,739 acre-ft/yr during 1981–2011. 

Total mean annual groundwater use in Reach II was similar 

but slightly less than in Reach I, with 14,098 acre-ft/yr 

during 1967–2011; 19,963 acre-ft/yr during 1970–80; and 

12,285 acre-ft/yr during 1981–2011.

Irrigation composed 72 percent of groundwater use 

in Reach I and 48 percent of groundwater use in Reach II 

during the 1967–2011 period. Public water supply was a 

much smaller proportion of total groundwater use in Reach 

I (15 percent) than in Reach II (39 percent). The proportion 

of groundwater use for power was 10 percent in Reach I 

and 5.2 percent in Reach II. All other water-use categories 

in Reach I only composed 2.2 percent of groundwater use 

in Reach I. In Reach II, industrial, mining, and commercial 

categories combined accounted for 4.4 percent of groundwater 
2 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

use; recreation, fish, and wildlife groundwater use accounted 

for 2.3 percent; and nonirrigated agriculture accounted for 

1.5 percent of groundwater use.

Permian-age bedrock underlies the Beaver-North 

Canadian River alluvial aquifer. In the east, the Dog Creek 

Shale, the Duncan Sandstone, and the Blaine and Chickasha 

Formations, none of which are notable sources of groundwater 

in the study area, underlie the Beaver-North Canadian River 

alluvial aquifer. In the northwestern part of Reach I, bedrock 

is composed of the Rush Springs and Marlow Formations, 

which are productive aquifers in some areas. The Cloud Chief 

Formation is not a source of groundwater.

One hydrogeological unit was delineated in the BeaverNorth Canadian River alluvial aquifer, composed of the terrace 

deposits and alluvium, with limited flow between this unit and 

bedrock units. Groundwater in this aquifer generally flows 

from northwest to southeast and across the aquifer toward the 

Beaver and North Canadian Rivers. 

Groundwater recharge from precipitation was estimated 

for the entire Beaver-North Canadian River alluvial aquifer 

and then itemized for both reaches by using a soil-waterbalance (SWB) model. At two locations in Reach I, a 

water-table fluctuation method was used to estimate local 

recharge. Total mean annual groundwater recharge from the 

soil-water-balance method was estimated to be approximately 

136,400 acre-ft in Reach I and 82,400 acre-ft in Reach II; 

the mean annual recharge for both reaches combined was 

approximately 218,800 acre-ft. Two sites in Reach I located at 

observation wells with continuous water-level measurements 

and nearby streamflow-gaging stations with precipitation 

gages were used to estimate the percentage of precipitation 

that becomes groundwater recharge. The Woodward site was 

located at observation well OW-4 near the Woodward, Okla. 

(07237500), streamflow-gaging station. Total precipitation 

and recharge for the Woodward and Seiling sites were 

calculated for the water year 2013. The Woodward site had a 

total of 14.18 in. of precipitation and 6.3 in. of recharge was 

calculated, equaling 44 percent of precipitation. The mean 

percentage of precipitation that was estimated to become 

recharge in the SWB model for the period 1980–2011 at that 

location was 9.2 percent, although adjacent SWB-model cells 

were as high as 20 percent of precipitation. The Seiling site 

had a total of 26.84 in. of precipitation during the water year 

2013, and a total of 6.9 in. of recharge was estimated, equaling 

25.9 percent of precipitation. At the Seiling site, the mean 

percentage of precipitation that became recharge in the SWB 

model for the period 1980–2011 was 23.0 percent.

The principal inflow to the Beaver-North Canadian River 

alluvial aquifer was estimated to be surface recharge from 

precipitation, and plant evapotranspiration was estimated to be 

the greatest discharge, followed by stream and lake base flow, 

groundwater pumping, and flow to seeps and springs along 

the eastern margin of the aquifer. Reach I also included inflow 

from the High Plains aquifer as lateral inflow of groundwater, 

though this flow was estimated to be a very minor component 

of the total water budget. Most of the Beaver and North 

Canadian Rivers were determined to be gaining streamflow 

from groundwater, but several reaches in Reach I upstream 

from Wolf Creek were determined to be losing streamflow 

through infiltration to the aquifer.

Aquifer hydrogeologic characteristics were estimated 

from borehole lithologic logs, well-construction information, 

and published aquifer tests and during numerical model 

calibration. The maximum saturated aquifer thickness in 

Reach I was estimated to be 308 ft, and the mean thickness 

was estimated to be 36 ft. The maximum saturated thickness 

in Reach II was estimated to be 86 ft, and the mean thickness 

was estimated to be 29 ft. Mean hydraulic conductivity of 

Reach I was estimated to be 70 feet per day (ft/d) with a range 

of 7–279 ft/d. Mean hydraulic conductivity in Reach II was 

estimated to be 92 ft/d with a range of 4–279 ft/d.

Both reach models were calibrated manually by using 

trial-and-error adjustment of recharge, hydraulic conductivity, 

specific yield, and conductance of boundary conditions. The 

Reach I model used 28 head observations during the steadystate period of 1980 and 487 head observations during the 

transient period of 1981–2011. The root-mean-square error of 

head residuals (observed minus simulated head) was 3.86 ft, 

and 83 percent of head residuals were between -5 and 5 ft. 

The Reach II model was calibrated to 75 steady-state head 

observations and 134 head observations during the transient 

period. The root-mean-square error of head residuals for 

that reach was 3.58 ft, and similar to Reach I, 85 percent of 

residuals were between -5 and 5 ft.

Several analyses were performed by using the numeric 

groundwater-flow models as predictive tools, including 

estimating the EPS pumping rate for both reaches. The EPS is 

defined by the Oklahoma Water Resources Board as an annual 

per-acre groundwater-pumping rate that will reduce saturated 

thickness in half of the aquifer to 5 ft or less over a period of 

20 years; additional estimates were made for periods of 40 and 

50 years. Other analyses included using models to estimate 

the effects of groundwater pumping and a prolonged drought 

on groundwater in storage and streamflow and lake storage of 

water.

The EPS pumping rate was found to be approximately 

0.57 acre-feet per acre per year ([acre-ft/acre]/yr) in Reach 

I and 0.73 (acre-ft/acre)/yr in Reach II for a 20-year period. 

For a 40-year period, the annual EPS pumping rate was 

determined to be 0.54 (acre-ft/acre)/yr in Reach I and 0.61 

(acre-ft/acre)/yr in Reach II. For a 50-year period, the EPS 

pumping rate was determined to be 0.53 (acre-ft/acre)/yr in 

Reach I and 0.61 (acre-ft/acre)/yr in Reach II.

Groundwater pumping at the 2011 rate for 50 years 

resulted in a 3.6-percent decrease in the amount of water in 

groundwater storage in Reach I and a decrease of 2.5 percent 

in the amount of groundwater in storage in Reach II. A 

cumulative 32-percent increase in pumping greater than 

the 2011 rate over a period of 50 years caused a decrease in 

groundwater storage of 4.0 percent in Reach I and 3.3 percent 

in Reach II.
Introduction 3

A hypothetical severe drought was simulated by 

using aquifer recharge flow rates during the drought year 

of 2011 for a period of 10 years. All other flows including 

evapotranspiration and groundwater pumping were set at 

estimated 2011 rates. The hypothetical drought caused a 

decrease in water in aquifer storage by about 7 percent in 

Reach I and 7 percent in Reach II. Another analysis of the 

effects of hypothetical drought estimated the effects of drought 

on streamflow and lake storage. The hypothetical drought was 

simulated by decreasing recharge by 75 percent for a selected 

10-year period (1994–2004) during the 1980–2011 simulation. 

In Reach I, the amounts of water stored in Canton Lake and 

streamflow at the Seiling, Okla., streamflow-gaging station 

were analyzed. Streamflow at the Seiling station decreased by 

a mean of 75 percent and was still diminished by 10 percent 

after 2011. In Reach II, the effect of drought on the streamflow 

at the Yukon, Okla., streamflow-gaging station was examined. 

The greatest mean streamflow decrease was approximately 

60 percent during the simulated drought, and after 2011, the 

mean decrease in streamflow was still about 5 percent. Canton 

Lake storage decreased by as much as 83 percent during the 

simulated drought and did not recover by 2011.

Introduction

The Beaver-North Canadian River alluvial aquifer is a 

long, narrow surficial aquifer that underlies the Beaver and 

North Canadian River Valley in western and northwestern 

Oklahoma (fig. 1). The Beaver-North Canadian River alluvial 

aquifer is one of several alluvial aquifers along rivers that 

cross western Oklahoma, including the adjacent Cimarron and 

Canadian Rivers, and is a source of water for Oklahoma City, 

local municipalities, domestic supplies, wildlife, agriculture, 

and oilfield uses. The Beaver River enters the Oklahoma 

Panhandle from New Mexico and composes the headwaters of 

the North Canadian River at the confluence of Beaver River 

with Wolf Creek (fig. 1).

Because of increasing water demands, depletion of water 

in the High Plains aquifer to the west, and recurring droughts, 

effective water resources management of the Beaver-North 

Canadian River alluvial aquifer is essential. Effective 

management required an updated comprehensive study of 

the hydrogeologic system of this aquifer. Streamflows in the 

Beaver and North Canadian Rivers have decreased since 

1971, at least in part because of groundwater depletion and 

reduced stream base flow from the area underlain by the High 

Plains aquifer (Wahl and Tortorelli, 1997). These trends could 

reduce available surface water for Oklahoma City during 

dry periods. The 2012 Oklahoma Comprehensive Water Plan 

(OCWP) (Oklahoma Water Resources Board, 2012) identified 

watershed basin 51, which includes the downstream half of 

the Beaver-North Canadian River alluvial aquifer, as a “hot 

spot” for water-supply shortages. The total water demand in 

central Oklahoma is projected to increase by approximately 

32 percent from 2010 to 2060, during which surface-water 

and groundwater shortfalls are forecast (Oklahoma Water 

Resources Board, 2012). A priority recommendation of the 

OCWP was to complete updates of hydrologic investigations 

and to analyze groundwater and surface-water interactions in 

selected aquifers in Oklahoma, including the Beaver-North 

Canadian River alluvial aquifer. The study described in this 

report is a cooperative effort between the U.S. Geological 

Survey (USGS) and the Oklahoma Water Resources Board 

(OWRB) to provide an updated analysis of the hydrology, 

hydrogeology, and groundwater-flow system, and new 

numerical groundwater-flow models with predictive 

simulations of selected future scenarios for the Beaver-North 

Canadian River alluvial aquifer.

Purpose and Scope

The purpose of this report is to describe the hydrology, 

hydrogeological framework, and groundwater flow, including 

flow between groundwater and surface water, in the BeaverNorth Canadian River alluvial aquifer in northwestern 

Oklahoma. This report describes the methods, construction, 

calibration, and results of numerical groundwater-flow models 

used to simulate groundwater flow, forward simulations used 

to calculate equal-proportionate-share (EPS) groundwaterpumping rates, and the effects of various 50-year future 

scenarios including increased groundwater pumping and 

severe droughts on the groundwater system.

Location and Description of Study Area 

The study area is defined as the extent of the BeaverNorth Canadian River alluvial aquifer as delineated by the 

OWRB (Oklahoma Water Resources Board, 2012). The width 

of the Beaver-North Canadian River alluvial aquifer varies 

from 4 to 12 miles (mi). This aquifer underlies approximately 

1,245 square miles (mi2) of land along approximately 175 

mi of the Beaver and North Canadian Rivers from the 

Oklahoma Panhandle to the western edge of Oklahoma City 

(fig. 1). The aquifer is divided into two water-management 

subareas referred to as “Reach I” and “Reach II” by the 

OWRB (Oklahoma Water Resources Board, 2012). Reach I 

includes the Beaver-North Canadian River alluvial aquifer 

from the northwestern end, where it is defined by the OWRB 

as beginning at the western boundary of Harper County, to 

Canton Dam. The area of Reach I is approximately 874 mi2, 

and the area of Reach II is approximately 371 mi2. Reach II 

extends from Canton Dam to the western edge of Oklahoma 

City where the aquifer narrows and available groundwater is 

limited. Reach I and Reach II are hydraulically connected; 

the location of the division between the two areas is for water 

management and is not at the location of a groundwater 

boundary.
4 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

Gage

Oklahoma City

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River

CANTON DAM

100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

OKLAHOMA

Area enlarged

Beaver-North Canadian River

alluvial aquifer Oklahoma City

Beaver

07234000

07235000

07242000

Beaver-North Canadian River 

 alluvial aquifer (BNCA)

 BNCA Reach I

 BNCA Reach II

Streamflow-gaging station and number

Observation well and name

Observation well with continuous

 water-level measurements and name

EXPLANATION

07236500

OW–7

OW–5

07235600

07236500

07239300

07239700

07239500

07240200 07239450

07239000

07238500

07237500

07238000

OW–8

OW–2

OW–1

OW–3

OW–4

OW–5

OW–6

OW–7

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

Figure 1. Locations of the Beaver-North Canadian River alluvial aquifer, reaches, hydrological features, observation wells, streamflowgaging stations, and cities, northwestern Oklahoma. 
Introduction 5

Previous Investigations

A hydrogeologic investigation of Reach I is reported 

in Christenson (1983), and a hydrogeologic investigation of 

Reach II is reported in Davis and Christenson (1981). Both 

of those reports included compilations of hydrologic data, 

descriptions of the hydrogeology and hydrological system, 

and generalized numerical groundwater-flow models using 

methods of Trescott (1975) with 1-mi square cells. Both 

reports included a transient simulation (1975–80) that was 

used by the OWRB to manage groundwater resources in the 

respective reaches. The study described in this report is an 

update of both Davis and Christenson (1981) and Christenson 

(1983) and uses streamflow measurements from both reports. 

Model parameters and the hydrogeologic framework from 

those two reports were not used because the models presented 

in this report are more detailed and incorporate additional data 

not available when those two reports were published.

Wahl and Tortorelli (1997) describe a substantial decrease 

in streamflow after 1971 in the North Canadian River at 

Woodward, Okla. (07237500), and North Canadian River 

near Seiling, Okla. (07238000), streamflow-gaging stations. 

These two stations are referred to in the remainder of this 

report as the “Woodward streamflow-gaging station” and 

“Seiling streamflow-gaging station,” respectively (fig. 1). The 

streamflow decrease was preceded by substantial declines in 

groundwater levels in the High Plains aquifer upstream from 

Reach I, with no corresponding decrease in precipitation. 

The Seiling streamflow-gaging station measures streamflow 

that includes inflow from the Wolf Creek tributary. The 

primary reason for the reduced streamflow at these stations 

was interpreted to be decreased base flow to the Beaver River 

related to depletion of groundwater in the High Plains aquifer. 

Base flow in the Beaver River where the river flows over 

the Beaver-North Canadian River alluvial aquifer was not 

determined to have a significant trend.

Zume and Tarhule (2008) describe a study that included 

a multilayer numerical groundwater-flow model of Reach 

I of the Beaver-North Canadian River alluvial aquifer that 

examined streamflow depletion from groundwater pumping; 

however, because model layer details and the values of 

hydraulic parameters were not reported, parameter values from 

Zume and Tarhule (2008) were not directly used in the models 

constructed for the study described in this report.

Mogg and others (1960) is a comprehensive analysis 

of the Beaver-North Canadian River alluvial aquifer 

hydrogeology near the southeastern end of Reach II in 

Canadian County, including hydraulic properties from aquifer 

tests and textural properties of the aquifer, recharge, and 

groundwater consumption through evapotranspiration (ET). 

Information from Mogg and others (1960) was used in the 

study described in this report. Bingham and Moore (1975) is 

part of the Oklahoma Geological Survey Hydrologic Atlas 

that described groundwater resources of the Oklahoma City 

quadrangle and provided a schematic description of hydrology 

and aquifer characteristics for this study.

An analysis of streamflow depletion caused by well 

pumping near the city of El Reno (fig. 1) and results of an 

aquifer test to estimate aquifer hydraulic properties were 

reported in Fox and Kizer (2009). Hydraulic properties from 

Fox and Kizer (2009) were included in the model described in 

this report.

Heran and others (2003) is a geologic map that 

covers the entire study area. The geology and hydrology, 

including information about the underlying bedrock and 

measurements of the hydraulic properties of the Beaver-North 

Canadian River alluvial aquifer at two different locations in 

Woodward County are described in Wood and Stacy (1965). 

An Oklahoma Geological Survey atlas of the geology and 

hydrology of the Woodward quadrangle (Morton, 1980) 

provides background hydrogeologic information. Information 

from Wood and Stacy (1965) and Morton (1980) was included 

in the study described in this report.

Land Use and Population

Land use for the study area during 1992, 2001, and 2006 

was described by using tabulated and spatially distributed 

estimated land cover from the National Land Cover Database 

(NLCD) (Multi-Resolution Land Characteristics Consortium, 

2013). Most of the area overlying the Beaver-North Canadian 

River alluvial aquifer was categorized in these 3 years as rural 

grazing and cultivated agriculture. Categories of land use in 

the study area include planted/cultivated cropland, livestock, 

grassland/herbaceous plants, forest, shrubland, wetland, 

barren, and developed in small rural communities.

Grassland/herbaceous plants composed 74 percent of the 

1992 NLCD classification (Vogelmann and others, 2001) in 

Reach I—52 percent upland grasses and forbs typically used 

for grazing and 22 percent planted/cultivated crops. Cultivated 

crops were almost entirely winter wheat and alfalfa. Other 

land-use classes included 15 percent shrubland, 7 percent 

forest, 2 percent open water, 1 percent wetlands, and less than 

1 percent developed and barren. In 2001 (Homer and others, 

2007) and 2006 (Fry and others, 2011), the only substantial 

change in land-use acreage from 1992 was an increase in 

developed land of approximately 5 percent. Area classified 

as shrubland decreased to 1 percent in 2001 and increased to 

2 percent in 2006 (Homer and others, 2007; Fry and others, 

2011).

Land use in Reach II was 64 percent cultivated crops in 

1992, with 20 percent being grassland/herbaceous, 8 percent 

being forest, 3 percent being shrubland, and 1 percent being 

developed. In 2001, the proportion of the area classified 

as cultivated crops in Reach II decreased to 54 percent, 

grassland/herbaceous increased to 30 percent, developed land 

increased to 6 percent, and shrubland was virtually nonexistent 

(Homer and others, 2007). There were no appreciable changes 

in Reach II land use from 2001 to 2006 (Fry and others, 2011).

Review of the U.S. Census data for counties in the study 

area indicated that from 1980 to 2010 population remained 

relatively constant in the western counties of Harper and 
6 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Woodward (U.S. Census, 2013). The population of Blaine and 

Major Counties in the central part of the study area decreased 

slightly, and the population of Canadian County in the east 

almost doubled, most likely because of the proximity of that 

county to Oklahoma City. 

Water Use and Management

Surface-water use for the Beaver and North Canadian 

Rivers and groundwater use for the Beaver-North Canadian 

River alluvial aquifer are managed by the OWRB on the 

basis of the 1978 water law and the OCWP (Oklahoma Water 

Resources Board, 2012). Surface-water use is a minor part of 

the Beaver and North Canadian Rivers water system budget 

(Oklahoma Water Resources Board, 2013). Surface-water 

features in the Beaver-North Canadian River alluvial aquifer 

hydrologic system include the Beaver and North Canadian 

Rivers, Fort Supply Lake, Canton Lake, and Lake Overholser 

(fig. 1). Reservoirs are primarily used to store streamflow that 

is later released and used downstream. The most substantial 

surface-water diversion is into the Lake Hefner Canal near the 

downstream end of Reach II (fig. 2). Because of the relatively 

small volumes of water diverted from ponds and intermittent 

streams, the study described in this report only considered 

diversions from the Beaver and North Canadian Rivers.

Long-term surface-water withdrawal permits have been 

issued by the OWRB, and the permitted volume was used 

in this report to estimate annual water use from the Beaver 

and North Canadian Rivers. During the study period, seven 

diversions (fig. 2) were issued to remove water from Reach I, 

with an annual mean of 2,000 acre-feet (acre-ft) being diverted 

(Oklahoma Water Resources Board, 2014). There were 14 

diversions from Reach II during this period, with a mean 

annual permitted volume of approximately 81,000 acre-ft, 

which included a diversion into Lake Hefner Canal for the 

Oklahoma City public water supply.

Temporary, 3-month water-use permits have been issued 

by the OWRB for surface-water diversions, shown on figure 2 

as temporary surface-water diversions. Temporary permits 

allow a specified volume to be diverted over a 3-month 

period (Oklahoma Water Resources Board, 2014). During the 

period of this study, 17 temporary surface-water diversions 

from the Beaver and North Canadian Rivers were active in 

Reach I, with a total permitted volume of 2,000 acre-ft, and 

41 diversions were active in Reach II, with a total volume of 

38,000 acre-ft. 

As with surface water, selected groundwater users in 

Oklahoma are required to obtain a permit from the OWRB and 

have been required to report various aspects of their annual 

water use. A water-use permit allows a maximum annual water 

volume to be pumped from one or more wells. The actual 

volume of water pumped for a permit is estimated by the 

OWRB on the basis of other information provided by water 

users depending on the category of water use. The period of 

water use data analyzed for the study described in this report 

includes 1967–2011 with the exception of 1992, which did not 

have sufficient data.

Annual reporting of groundwater use has not been 

required for self-supplied domestic water wells, agricultural 

use that is less than 5 acre-feet per acre per year ([acre-ft/

acre]/yr), or water pumped for irrigation and applied to less 

than 3 acres (Oklahoma Water Resources Board, 2014). 

For the OWRB to estimate irrigation usage for larger farms 

several parameters were required to be estimated by water 

users and reported. Before 1980, irrigators were required 

to report the crop type, the frequency of irrigation, and 

the number of irrigated acres (Oklahoma Water Resources 

Board, 2014). For 1980 and later, irrigators were required to 

include the number of applications and the inches of water 

per application or the number of applications (Oklahoma 

Water Resources Board, 2014), which reduced uncertainty 

by allowing irrigation volumes to be calculated directly. If 

only the number of applications were reported by an irrigator, 

the inches of application were estimated by using a sliding 

scale, where the first six applications were assumed to be 4 

inches (in.) of water each. For applications 7–10, the amount 

of water was decreased to 3 in. each; applications 11–15 were 

assumed to be 2 in. each, and applications 16 and greater 

were each assumed to be 1 in. of water applied. The sum of 

all applications was then converted to feet and multiplied by 

the number of irrigated acres to determine acre-feet. Public 

water-supply use has been reported as the total annual volume 

pumped.

Other categories used by the OWRB to track water use 

include power, nonirrigated agriculture, recreation, mining, 

industrial, and commercial. Groundwater-use data were 

verified for 673 permits, and total annual groundwater use 

by category was determined for 1967–2011 for both reaches. 

Both reaches had a substantially higher water use from about 

1970 to 1980 (fig. 3) than the rest of the period. Thus, water 

use in the periods 1970–80 and 1981–2011, which were 

selected because the first period represents a time of high 

water use and the second period includes recent population 

growth and modern irrigation methods, were selected for 

detailed analysis.

The mean annual total groundwater use in Reach I was 

15,309 acre-feet per year (acre-ft/yr) during 1967–2011; 

20,724 acre-ft/yr (range 11,867 to 27,799 acre-ft/yr) during 

1970–80, and 13,739 acre-ft/yr (range 9,874 to 18,156 acre-ft/

yr) during 1981–2011 (table 1). Mean annual water use in 

Reach II was slightly less than in Reach I. Mean annual 

use in Reach II was 14,098 acre-ft/yr during 1967–2011; 

19,963 acre-ft/yr (range 12,520 to 28,046 acre-ft/yr) during 

1970–80; and 12,285 acre-ft/yr (range 7,869 to 17,548 acre-ft/

yr) during 1981–2011 (table 1). 
Introduction 7

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

Temporary (3-month) surface-water diversion

Long-term surface-water diversion

Groundwater-pumping well

 Irrigation

 Public supply

#

#

EXPLANATION

Beaver-North Canadian River 

 alluvial aquifer (BNCA)

 BNCA Reach I

 BNCA Reach II

Figure 2. Irrigation and public water-supply wells and surface-water diversions active during 1980–2011 in areas overlying the BeaverNorth Canadian River alluvial aquifer, northwestern Oklahoma.
8 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

EXPLANATION

Water-demand category (Oklahoma

 Water Resources Board, 2014)

 Irrigation

 Public supply

 Power

 Nonirrigated agriculture 

 Recreation, fish, and wildlife

 Mining

 Industrial

 Commercial

 Other

Mean annual groundwater use, in

 acre-feet per year

B. Beaver-North Canadian River alluvial aquifer Reach II

A. Beaver-North Canadian River alluvial aquifer Reach I

No data No data

0

10,000

20,000

30,000

0

10,000

20,000

30,000

Total estimated annual groundwater use,

in acre-feet per year

Total estimated annual groundwater use,

in acre-feet per year

Year

Year

1967 1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011

1967 1971 1975 1979 1983 1987 1991 1995 1999 2003 2007 2011

Figure 3. Total estimated annual groundwater use 1967–2011 by water demand category for A. Reach I and B. Reach II of the BeaverNorth Canadian River alluvial aquifer, northwestern Oklahoma.

Table 1. Summary statistics of groundwater use for selected periods for the Beaver-North Canadian River alluvial aquifer.

[All units in acre-feet per year. The year 1992 was excluded from this analysis; data from Oklahoma Water Resources Board (2014)]

Period

1970–80 1981–2011 1967–2011

Reach I Reach II Reach I Reach II Reach I Reach II

Mean 20,724 19,963 13,739 12,285 15,309 14,098

Minimum 11,867 12,520 9,874 7,869 9,874 7,869

Maximum 27,799 28,046 18,156 17,548 27,799 28,046
Hydrology 9

The largest mean annual groundwater use during 

1967–2011 for both reaches was for irrigation, followed by 

public water supply (fig. 4; table 2), and in both reaches, the 

difference in groundwater use between the 1970–80 and 1981–

2011 periods was greater for irrigation. The mean annual total 

groundwater use was similar in both reaches for all periods, 

though in Reach II, irrigation was less than in Reach I and 

decreased more during 1981–2011. Industrial groundwater use 

also increased substantially in Reach II after 1980 (Oklahoma 

Water Resources Board, 2013).

Irrigation composed 72 percent of groundwater use in 

Reach I (fig. 4A) and 48 percent of groundwater use in Reach 

II (fig. 4B) during 1967–2011. Public water supply was a 

much smaller proportion of total groundwater use in Reach I 

(15 percent) than in Reach II (39 percent). Groundwater use 

for power was 10 percent in Reach I (fig. 4A) and 5.2 percent 

in Reach II (fig. 4B). All other water-use categories only 

composed 2.2 percent of groundwater use in Reach I (fig. 4A). 

In Reach II, industrial, mining, and commercial categories 

composed 4.4 percent of groundwater use; recreation, fish, 

and wildlife was 2.3 percent; and nonirrigated agriculture and 

other was 1.5 percent (fig. 4B).

Mean annual estimated groundwater use during 1970–80 

peaked in 1977 in Reach I (fig. 3A) and in 1976 in Reach II 

(fig. 3B). Total mean annual groundwater use for the period 

1981–2011 in both reaches was more consistent, and the 

minimum groundwater use for Reach I was in 1995 and Reach 

II was in 1996 (fig. 3). The maximum annual pumping for the 

period 1981–2011 in Reach I occurred in 1982 and in Reach II 

occurred in 2001.

Mean annual groundwater use for public water supply 

was very similar between the two time periods, with a larger 

proportion of total groundwater use in Reach II than in Reach I 

(fig. 4; table 2). The mean annual groundwater use for power 

in 1981–2011 was about half that of 1970–80 in Reach I but 

was nearly the same during the same two periods in Reach II 

(table 2). Groundwater use for power was 10 percent of total 

groundwater use in Reach I (fig. 4A) but only approximately 

5 percent in Reach II (fig. 4B). Groundwater use for mining 

decreased in Reach II during 1981–2011 compared to 

1970–80 (fig. 3; table 2). In Reach I, recreation, mining, 

industrial, and commercial water uses were much less than 

in Reach II in all time periods (table 2). Groundwater use for 

nonirrigated agriculture was minimal before 1996 and similar 

in both reaches (fig. 3). There was much more recreational 

groundwater use in Reach II than in Reach I (table 2), and 

most of the recreational groundwater use occurred before 1989 

in Reach II (fig. 3B). 

Hydrology

The hydrology of the study area relates to water available 

for the Beaver-North Canadian River alluvial aquifer. Climate 

and streamflow characteristics are described in this section.

Climate

The climate of the Beaver-North Canadian River 

alluvial aquifer trends from warmer and drier semiarid in the 

northwest to wetter and slightly cooler humid-temperate in 

the southeast (Oklahoma Climatological Survey, 2011), which 

affects important components of the hydrologic system. The 

mean daily temperature across the Beaver-North Canadian 

River alluvial aquifer ranges from 58 to 60 degrees Fahrenheit 

(°F) and increases from the southeast to northwest (Oklahoma 

Climatological Survey, 2015a, b). The mean daily temperature 

for Harper County at the northwestern end of the study area 

(fig. 1) during the period 1960–2013 ranged from a high 

in July of 83.2 °F to a low in January of 35 °F (Oklahoma 

Climatological Survey, 2015a). During the same period in the 

southeastern end of the aquifer in Oklahoma County, mean 

daily temperature ranged from a high of 81.9 °F in July to a 

low of 36.6 °F in January (Oklahoma Climatological Survey, 

2015b).

Precipitation measurements were obtained from the 

National Climatic Data Center for all available weather 

stations on and surrounding the study area for the period from 

1980 to 2011 (National Climatic Data Center, 2013). Mean 

annual precipitation was interpolated across the study area 

as described in the “Groundwater Recharge” section of this 

report; the interpolated mean annual precipitation and most 

of the weather stations used in the interpolation are shown on 

figure 5. Interpolated mean annual precipitation for 1980–2011 

trended gradationally from 23.5 in. of precipitation in the 

west to 35.7 in. of precipitation in the east, an increase of 52 

percent (fig. 5).

Precipitation measurements from four weather stations 

distributed across the study area with long periods of record 

were used to describe general climatic conditions of the 

Beaver-North Canadian River alluvial aquifer. The weather 

stations included Gate, Woodward, Watonga, and Will Rogers 

World Airport (fig. 5). Years with less than 10 months of data 

were removed, and trace amounts of precipitation were not 

included. The earliest precipitation observations were recorded 

in 1908 at the Woodward weather station, which stopped 

recording observations after 2012; data collection continued 

at Gate, Watonga, and Will Rogers World Airport weather 

stations through 2013 (table 3). The station with the latest 

start year is Gate, at which data collection began in 1960. The 

period from 1960 to 2012, during which all of the stations 

were active, was used to describe precipitation across the 

study area.

The combined mean annual precipitation for all four of 

the weather stations during the period 1960–2012 was 27.6 

in. (table 3) (Oklahoma Climatological Survey, 2014). As 

shown on figure 5, the mean annual precipitation increased 

from west to east: 21.7 in. at Gate, 24.5 in. at Woodward, 

29.8 in. at Watonga, and 34.4 in. at Will Rogers World Airport 

(table 3).
10 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Water-demand category from Oklahoma Water Resources Board, 2014

Industrial, mining,

and commercial

4.4 percent

Public supply

39 percent

Power

5.2 percent

Recreation, fish,

and wildlife

2.3 percent

Irrigation

72 percent

Public supply

15 percent

Power

10 percent 

All other

2.2 percent 

Irrigation

48 percent

Nonirrigated

 agriculture

and other

1.5 percent

A. Beaver-North Canadian River alluvial aquifer Reach I B. Beaver-North Canadian River alluvial aquifer Reach II

Figure 4. Distribution of mean annual groundwater use for 1967–2011 by percentage for water-use categories for A. Reach I and 

B. Reach II of the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.

Table 2. Estimated mean annual groundwater use for selected periods by use category in acre-feet, Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma.

[All water use in mean acre-feet per year. The year 1992 was excluded because of missing data; IRR, irrigation; PWS, public water supply; AGR, nonirrigation 

agriculture; COM, commercial; NA, not available; data from Oklahoma Water Resources Board (2014)]

Period

Water-use category

IRR PWS Power AGR Recreation Mining Industrial COM Other Total

Reach I

1970–80 15,493 2,746 2,418 NA 4 0 62 1 0 20,724

1981–2011 9,866 2,144 1,282 328 19 10 76 1 13 13,739

1967–2011 11,033 2,368 1,574 223 17 7 67 1 19 15,309

Reach II

1970–80 13,750 4,310 761 NA 547 453 41 61 3 19,963

1981–2011 4,415 5,952 742 283 217 254 301 112 9 12,285

1967–2011 6,708 5,496 738 214 320 303 219 92 8 14,098

Mean 8,871 3,932 1,156 219 169 155 143 47 14 14,704
Hydrology 11

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

CADDO COUNTY COUNTY

LOGAN COUNTY

100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

Precipitation data from National Climatic Data Center (2013)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

EXPLANATION

Aquifer missing

Beaver-North Canadian River alluvial

 aquifer (BNCA) boundary

Weather station with precipitation and

 temperature measurements (stations

 described in this report are labeled)

Mean annual precipitation,

 1980–2011, in inches

35.7

23.5

GATE

GATE

WOODWARD

WATONGA

WILL ROGERS

WORLD AIRPORT

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Figure 5. Interpolated mean annual precipitation and cooperative observer weather stations for the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma, from daily weather-station data over the period 1980–2011.
12 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Table 3. Statistical summary of precipitation at selected weather stations for the Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma.

[Data from National Climate Data Center (2013)]

Station name Period 

of record

Number 

of years

Period of record 

mean annual precipitation 

(inches)

1960–2012 mean annual 

precipitation 

(inches)

Gate 1960–2013 54 21.7 21.7

Woodward 1908–2012 105 23.3 24.5

Watonga 1928–2013 86 27.6 29.8

Will Rogers World Airport 1948–2013 66 33.8 34.4

Mean of all stations 26.6 27.6

To describe seasonal precipitation and long-term wet and 

dry periods for the two reaches of the Beaver-North Canadian 

River alluvial aquifer, data from two weather stations 

centrally located in both reaches were used: the Woodward 

weather station in Reach I and the Watonga weather station in 

Reach II (fig. 5). Mean monthly precipitation for the period 

1960–2012 showed similar seasonality at both stations and 

was consistently greater at the Watonga station (fig. 6). Mean 

monthly precipitation was greatest during May (3.8 in. at 

Woodward and 4.5 in. at Watonga), and the driest month at 

both stations was January (0.75 in. at Woodward and 1.0 in. at 

Watonga). Precipitation decreased from May to July, followed 

by typically wet falls, which were then followed by decreases 

in precipitation through January. At both weather stations 

mean monthly precipitation increased gradually from February 

to April, then increased substantially in May.

Long-term precipitation records from the Woodward and 

Watonga weather stations were used to delineate wet and dry 

periods by calculating the deviation of the 5-year weighted 

moving average of the total annual precipitation from the 

mean annual precipitation for the period of record. Wet and 

dry periods were compared to timing of regional hydrologic 

droughts that have affected the Beaver-North Canadian River 

alluvial aquifer during the period of record at each station. Dry 

periods were compared to periods of hydrological drought that 

have affected the region.

Since 1900, there have been five major hydrologic 

drought periods in the study area region: 1909–18, 1929–41 

(the Dust Bowl), 1952–56, 1961–72, and 1976–81 (Oklahoma 

Climatological Survey, 2011). Precipitation at the Woodward 

weather station was below normal during the 1909–18 

hydrologic drought (fig. 7). The Dust Bowl drought of the 

1930s was of shorter duration in the study area than the 

regional drought, and decreases in precipitation during the 

1952–56 and 1961–72 droughts were very pronounced at 

Woodward. The 1976–81 drought did not appear to affect 

the Woodward weather station, and there is a dry period 

during 1988–95 and a generally decreasing and below-normal 

period from 2002 to 2011 that do not correspond to a regional 

hydrologic drought. 

There were extended below-normal precipitation periods 

at the Watonga weather station that coincided with the last four 

regional hydrologic droughts, and the droughts of the 1950s 

and 1960s were of longer duration at Watonga than the major 

regional droughts (fig. 8). Unlike at the Woodward weather 

station, above-normal precipitation periods were measured at 

the Watonga weather station from 1981 to 2001 and from 2005 

to 2008; however, below-normal precipitation during 2009–11 

was measured at the Watonga station.

Streamflow Characteristics

Median monthly streamflows in the Beaver River in 

and just upstream from the study area were highly variable 

from 1980 to 2011 (fig. 9). Streamflow in the North Canadian 

River is controlled by Canton Lake, and streamflow in Wolf 

Creek, which is the largest tributary to the North Canadian 

River in the study area, is controlled by Fort Supply Lake 

(fig. 1). Median monthly streamflow (U.S. Geological Survey, 

2013d) in the Beaver and North Canadian Rivers at three 

streamflow-gaging stations on and near Reach I is shown in 

figure 9. Reach I stations include, in order from upstream to 

downstream, the streamflow-gaging station at Beaver, Okla. 

(07234000), which is approximately 30 mi upstream from 

the study area and shown on the figure 1 inset map, and the 

Woodward and Seiling streamflow-gaging stations (fig. 1). 

Periods of record at these three streamflow-gaging stations 

include the period from 1980 to 2011.
Hydrology 13

Mean monthly precipitation,

 by station

 Woodward weather station

 Watonga weather station

EXPLANATION

January

February

March

April

May

June

July

August

September

October

November

December

Month

0

1

2

3

4

5

Precipitation, in inches

Figure 6. Mean monthly precipitation at Woodward and Watonga, Oklahoma, weather stations for the period 1960–2012.

Below historic average (5-year weighted moving average)

Above historic average (5-year weighted moving average)

Annual precipitation

Long-term (1908–2012) mean annual precipitation (24.8 inches)

EXPLANATION

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Year

0

10

20

30

40

50

Precipitation, in inches

Figure 7. Annual departure from the mean annual precipitation from 1908 to 2012 and 5-year weighted moving average for the 

Woodward weather station, Beaver-North Canadian River alluvial aquifer Reach I, northwestern Oklahoma.
14 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Below historic average (5-year weighted moving average)

Above historic average (5-year weighted moving average)

Annual precipitation

Long-term (1908–2013) mean annual precipitation (28.7 inches)

EXPLANATION

1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Year

0

10

20

30

40

50

60

Precipitation, in inches

Figure 8. Annual departure from the mean annual precipitation from 1928 to 2013 and 5-year weighted moving average for the 

Watonga weather station, Beaver-North Canadian River alluvial aquifer Reach II, northwestern Oklahoma. 

Median monthly streamflow, in cubic feet per second, by 

 U.S. Geological Survey streamflow-gaging station (fig. 1)

 Beaver River near Beaver, Okla. (07234000)

 North Canadian River near Woodward, Okla. (07237500)

 North Canadian River near Seiling, Okla. (07238000)

Median daily streamflow (88 cubic feet per second) at North

 Canadian River near Seiling, Okla. (07238000)

EXPLANATION

0

500

1,000

1,500

2,000

2,500

Streamflow, in cubic feet per second

Date

1980198219841986198819901992199419961998200020022004200620082010

Figure 9. Median monthly streamflow for streamflow-gaging stations at Beaver River near Beaver, Oklahoma (07234000), at the North 

Canadian River at Woodward, Okla. (07237500), and at the North Canadian River near Seiling, Okla. (07238000), and the median monthly 

streamflow at the Seiling station for Reach I.
Hydrogeological Framework 15

Streamflow in Reach I was highly variable with median 

daily streamflow at the Seiling streamflow-gaging station 

sometimes exceeding 2,000 cubic feet per second (ft3/s) 

compared to a median of median daily streamflow of 88 ft3/s 

(fig. 9). Streamflow also increased downstream, showed by 

the differences in streamflow among the Beaver, Woodward, 

and Seiling streamflow-gaging stations (fig. 9). The increase 

in streamflow was from a combination of base flow along the 

river channel and tributary inflows, including Wolf Creek via 

Fort Supply Lake, as described in the “Stream Base Flow” 

section of this report.

Median monthly streamflow for 1980–2011 is shown 

in figure 10 for North Canadian River streamflow-gaging 

stations in Reach II below Weavers Creek near Watonga, Okla. 

(07239300), and near El Reno, Okla. (07239500) (fig. 1). For 

the remainder of this report, these stations will be referred to 

as the “Watonga” and “El Reno” streamflow-gaging stations, 

respectively. Streamflow at the El Reno streamflow-gaging 

station typically was higher than the streamflow at the 

Watonga station, with the median streamflow at the El Reno 

streamflow-gaging station being 91 ft3/s (fig. 10). Streamflow 

in Reach II increased progressively downstream similar 

to streamflow in Reach I, although streamflow in Reach II 

was controlled by Canton Lake and the median streamflow 

was very similar to Reach I. In both reaches, the streamflow 

time-series graphs in figures 9 and 10 show a relatively wet 

period from 1986 to 1990, a relatively dry period from 1991 to 

1996, and a relatively wet period from 1996 to 2002.

Streamflow entering the Beaver-North Canadian River 

alluvial aquifer system in the study area from the Beaver 

River at Beaver, Okla., streamflow-gaging station (07234000) 

decreased from 1978 to 1994, primarily related to groundwater 

depletion in the High Plains aquifer and a resulting decrease in 

base flow to streams upstream from the study area (Wahl and 

Tortorelli, 1997). Wolf Creek drains the High Plains aquifer 

and contributes flow to the North Canadian River through 

Fort Supply Lake, but it is not known how much depletion 

of groundwater in the High Plains aquifer has affected Wolf 

Creek streamflow.

Hydrogeological Framework

The hydrogeological framework of the Beaver-North 

Canadian River alluvial aquifer describes the physical 

characteristics of the aquifer, including the geological setting, 

the characteristics and hydraulic properties of hydrogeological 

units, the potentiometric surface, and groundwater-flow 

directions. The hydrogeological framework was used to 

construct the numerical groundwater-flow models.

Median monthly streamflow, in cubic feet per second, by 

 U.S. Geological Survey streamflow-gaging station (fig. 1)

 North Canadian River below Weavers Creek near Watonga, Okla. (07239300)

 North Canadian River below Weavers Creek near El Reno, Okla. (07239500)

Median daily streamflow (91 cubic feet per second) at North

 Canadian River below Weavers Creek near El Reno, Okla. (07239500)

EXPLANATION

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

Streamflow, in cubic feet per second

1980198219841986198819901992199419961998200020022004200620082010

Date

Figure 10. Median monthly streamflow at the North Canadian River below Weavers Creek near Watonga, Oklahoma (07239300), and 

near El Reno, Okla. (07239500), streamflow-gaging stations and the median daily streamflow at the El Reno station for Reach II.
16 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Geology

The Beaver-North Canadian River alluvial aquifer 

is composed of alluvium and terrace, two Quaternary-age 

unconsolidated alluvial deposits that unconformably overlie 

bedrock units that range in age from the Permian to Tertiary 

(fig. 11). For most of the aquifer area, the alluvium and terrace 

deposits are physically and hydraulically connected, although 

in the lower parts of Reach II Permian units outcrop in an 

elongated band between alluvium and terrace deposits where 

both are missing. Only two of the underlying bedrock units 

are used as water sources, and no other Permian-age units are 

considered to contribute groundwater to the Beaver-North 

Canadian River alluvial aquifer groundwater-flow system.

Quaternary-age geologic units in the study area (fig. 11) 

consist of unconsolidated alluvium, dune sand, and terrace 

deposits. Dune sand is not differentiated in the geologic 

map of the study area from Heran and others (2003) but is 

described in Wood and Stacy (1965) as overlying the alluvium 

and terrace deposits throughout much of study area, and in 

some areas in Reach I, the landscape includes relic dunes and 

hummocky topography. The dune sand is 20–30 feet (ft) thick, 

well-sorted, medium- to fine-grained quartz sand in Woodward 

County (Myers, 1959; Wood and Stacy, 1965). Dune sand is 

typically above the water table and not a separate zone or unit 

of the aquifer, but because of the high permeability, dune sand 

can facilitate infiltration of precipitation and thus increase 

recharge to the aquifer.

Alluvium is delineated along the active channel of 

the Beaver and North Canadian Rivers and Wolf Creek 

as shown in figure 11, consisting of gravel, sand, silt, and 

clay (Myers, 1959) with an estimated mean thickness along 

the river channel of 30–40 ft and a maximum thickness of 

approximately 100 ft (Morton, 1980; Davis and Christenson, 

1981; Christenson, 1983). The alluvium is only a few hundred 

feet wide in parts of the northwestern parts of Reach I and 

widens to the southeast such that it is wider than terrace 

deposits in Canadian County (fig. 11). Terrace deposits were 

deposited by the Beaver and North Canadian Rivers as they 

migrated to the southwest in the approximate direction of the 

regional dip of the underlying Permian-age geologic units. The 

terrace deposits are topographically higher than the alluvium 

and consist of gravel, sand, silt, clay, and minor amounts 

of volcanic ash, bentonite, and soft caliche (Myers, 1959; 

Morton, 1980; Davis and Christenson, 1981; Christenson, 

1983). The terrace deposits are reported to have a mean 

thickness of between 60 and 70 ft and have been determined 

to be as thick as 150 ft (Morton, 1980). The terrace deposits 

on the northeastern margin of the aquifer have been eroded by 

widening of the adjacent Cimarron River Valley (fig. 1) and in 

places form the topographic drainage divide.

The Tertiary-age Ogallala Formation (To on fig. 11) 

consists of beds of moderately well sorted to poorly sorted 

sand and gravel, some of which are partially cemented by 

calcium carbonate (Myers, 1959). The mean thickness of 

the Ogallala Formation in the study area is 150 ft, and the 

maximum thickness is approximately 400 ft (Morton, 1980). 

Because the Ogallala Formation is difficult to differentiate from 

the alluvial and terrace deposits in borehole lithologic logs, 

Davis and Christenson (1981) included the Ogallala Formation 

as part of the Beaver-North Canadian River alluvial aquifer 

in the northwestern end of the study area where the alluvial 

deposits overlie the Ogallala Formation. For this report, the 

only location where the Beaver-North Canadian River alluvial 

aquifer is differentiated from the underlying Ogallala Formation 

is part of the terrace deposits in the Wolf Creek drainage 

(fig. 11). Where the Ogallala Formation is included, horizontal 

hydraulic conductivity (Kh) of the Beaver-North Canadian 

River alluvial aquifer is much lower because the Ogallala 

Formation is consolidated and includes beds of caliche and 

clay. The combined alluvium and Ogallala Formation makes the 

northwestern end of the Beaver-North Canadian River alluvial 

aquifer the thickest part of the aquifer.

Permian-age bedrock units exposed adjacent to and 

subcropping below the Beaver-North Canadian River alluvial 

aquifer are predominantly composed of fine-grained sandstone, 

siltstone, shale, dolomite, and gypsum (Heran and others, 

2003). Permian-age rocks have a general regional dip to the 

south-southwest of approximately 17 ft per mile (Morton, 

1980). In parts of the study area, Permian-age geologic units 

crop out in isolated areas within the alluvium and the terrace 

deposits because of protruding high spots on the irregular 

bedrock surface (Christenson, 1983). No notable geologic 

structures in bedrock units have been identified in the study 

area, although local-scale sinkhole development caused by 

groundwater dissolution of halite and gypsum in the Blaine 

Formation has resulted in minor folding in the area that 

includes Reach II (Morton, 1980). 

Permian-age units underlying the Beaver-North Canadian 

River alluvial aquifer from youngest to oldest, and moving 

from northwest to southeast include the Cloud Chief, Rush 

Springs, and Marlow Formations, Dog Creek Shale, Blaine 

Formation, Bison Shale, Chickasha Formation, and Duncan 

Sandstone. Where these units are present at the land surface and 

the approximate areas where they subcrop below the BeaverNorth Canadian River alluvial aquifer are shown on figure 11.

Most of Reach I is underlain by the Rush Springs and 

Marlow Formations (Pr and Pm in red on fig. 11, respectively) 

with two narrow areas along the northeastern margin of the 

aquifer upstream from Wolf Creek being underlain by the 

Cloud Chief Formation (Pcc in red on fig. 11). The Cloud 

Chief Formation is composed of shale and siltstone, with 

minor amounts of fine sandstone. The Rush Springs Formation 

consists of orange-brown fine-grained sandstone and siltstone, 

with interbedded red-brown shale, silty shale, and gypsum 

(Wood and Stacy, 1965). The Rush Springs Formation is 

the most permeable of the bedrock units in the area and is 

delineated by the OWRB as an aquifer southeast of the study 

area (Oklahoma Water Resources Board, 2012); it is considered 

to be hydraulically connected to the Beaver-North Canadian 

River alluvial aquifer. The Marlow Formation has texture 

similar to the Rush Springs Formation but with more silt and 

yields small quantities of water to domestic and stock wells 

(Wood and Stacy, 1965).
Hydrogeological Framework 17

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

Geology modified from Heran and others (2003)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

Pbi

Pd

Pdc

Pdc

Pc

Pb

To

To

Pm

Pcc

Pcc

Pr

Pdc

Pd Pbi

Psp

Qt

Pc

Pf

Qt

Qt

Psp

Pf To

Pr

Qt

Qt

Qal

To

Qt Pm

Pr

Pb

Qt

Pf

Pr

Pr Pm

Qt

Qt

Pch

Pch

Pm Pf

Qt

Pr

Pm

Pdc

Qt

Qal

Qal

Pr

Qt

Qt

Pr

Pcc

Pr

Pm

Pr

Qt

Qt

Pbi

Psp

Pdc

Pb

Pdc

Pr

Pcc

Pf

Pf

Pb

Qal

Qal

Pcc

Pr

Pf

Pm

Qt

Qal

Pm

ROMAN NOSE

STATE PARK

BOILING SPRINGS

STATE PARK

Subcrop contact (geologic unit in red)

Beaver-North Canadian River alluvial

 aquifer (BNCA) boundary

EXPLANATION

Alluvium (Quaternary)

Dune sand (Quaternary)

Terrace deposits (Quaternary)

Ogallala Formation (Tertiary)

Cloud Chief Formation (Permian)

Rush Springs Formation (Permian)

Marlow Formation (Permian)

Dog Creek Shale (Permian)

Blaine Formation (Permian)

Bison Shale (Permian)

Chickasha Formation (Permian)

Cedar Hill Sandstone (Permian)

Duncan Sandstone (Permian)

Flowerpot Shale (Permian)

Fairmont Shale (Permian)

Kingman Siltstone (Permian)

Salt Plains Formation (Permian)

To

Qt

Qd

Qal

Pcc

Pr

Pm

Pdc

Pb

Pbi

Pc

Pch

Psp

Pk

Pfa

Pf

Pd

Figure 11. The geology of the Beaver-North Canadian River alluvial aquifer area showing approximate delineation of bedrock units that 

underlie the aquifer.
18 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

The Dog Creek Shale (Pdc on fig. 11) is red-brown shale 

with discontinuous bands of silt and thin layers of dolomite 

that underlie a substantial part of the Beaver-North Canadian 

River alluvial aquifer in Reach II (Morton, 1980). The Dog 

Creek Shale has very low permeability and is not a source of 

water (Mogg and others, 1960; Wood and Stacy, 1965).

The Blaine Formation, Chickasha Formation, and Duncan 

Sandstone (Pb, Pc, and Pd on fig. 11, respectively) underlie 

the eastern extent of the Beaver-North Canadian River alluvial 

aquifer in Canadian County. The Blaine Formation consists 

of thin gypsum beds with thin beds of dolomite below each 

gypsum layer interbedded with red-brown shale (Fay, 1962; 

Bingham and Moore, 1975). The gypsum is highly soluble and 

forms dissolution features that provide conduits for springs 

to form just east of the Beaver-North Canadian River alluvial 

aquifer such as those at Roman Nose State Park (fig. 11). 

The Chickasha Formation (Pc on fig. 11), Duncan 

Sandstone (Pd on fig. 11), and Bison Shale (Pbi on fig. 11) 

underlie the southeastern-most parts of the Beaver-North 

Canadian River alluvial aquifer. The Chickasha Formation 

consists of mudstone conglomerate and red-brown to orangebrown silty shale and siltstone with minor amounts of orangebrown fine-grained sandstone (Bingham and Moore, 1975) 

that underlies the Beaver-North Canadian River alluvial 

aquifer in the area of the city of El Reno. The Duncan 

Sandstone is a red-brown to orange-brown fine-grained 

sandstone with some mudstone conglomerate and shale 

(Bingham and Moore, 1975) that underlies the Beaver-North 

Canadian River alluvial aquifer near the city of Yukon. The 

Bison Formation is a reddish-brown fine-grained sandstone 

and shale unit (Bingham and Moore, 1975). 

Hydrogeological Units

A hydrogeological unit is a continuous unit with 

consistent hydraulic properties that may or may not coincide 

with a single stratigraphic unit and is hydraulically distinct 

from vertically or laterally adjacent hydrogeological units 

in the same hydrogeological system. Each hydrogeological 

unit may include zones or distinct vertical intervals that are 

unique but are discontinuous and not considered to be distinct 

hydrogeological units.

Though two units—the alluvial and terrace units—

compose the Beaver-North Canadian River alluvial aquifer, 

both are included in the one hydrogeological unit because 

they have similar hydraulic properties, are typically laterally 

connected, and are not vertically juxtaposed. Dune sand is not 

mapped as a separate geologic unit in the study area.

In the northwestern part of Reach I, the Ogallala 

Formation is in contact with the terrace and alluvium 

both laterally and vertically, and the alluvium and terrace 

are mostly unsaturated. Thus, the Ogallala Formation is 

included in the Beaver-North Canadian River alluvial aquifer 

hydrogeological unit where it is overlain by alluvium, and 

the base of the unit is defined as the top of the Rush Springs 

Formation.

By using lithological borehole logs and modifying 

maps from Davis and Christenson (1981) and Christenson 

(1983), the altitude of the base of the Beaver-North Canadian 

River alluvial aquifer was mapped and is shown on figure 12 

with the estimated aquifer thickness. The aquifer base is 

approximate in the northwestern end where there are few 

borehole logs that distinguish the base of the Ogallala 

Formation from the Rush Springs Formation.

The base of the Beaver-North Canadian River alluvial 

aquifer is an erosional surface scoured by the Beaver and 

North Canadian Rivers. The bedrock surface was constructed 

by using lithologic borehole logs with sufficient detail to 

provide the altitude of the bedrock contact. Because the base 

is an erosional surface, it was contoured so that all points on 

the surface drain down the valley to the southwest. Because 

of numerous wells drilled since 1980, the base of the BeaverNorth Canadian River alluvial aquifer in this study is updated 

in this report by using additional well logs.

The thickness of the Beaver-North Canadian River 

alluvial aquifer as estimated in this report with the Ogallala 

Formation varies from nonexistent to 329 ft, and where the 

aquifer does not include the Ogallala Formation, it is typically 

less than 150 ft thick. There are elongated areas between the 

terrace and alluvium where the Beaver-North Canadian River 

alluvial aquifer is missing and the Duncan Sandstone outcrops.

Potentiometric Surface and Water-Level 

Fluctuations

Groundwater in the Beaver-North Canadian River 

alluvial aquifer generally flows downstream to the southeast 

and locally flows toward and discharges to the Beaver and 

North Canadian Rivers in most areas (fig. 13). The Beaver 

and North Canadian Rivers flow along the southwestern side 

of the valley, and recharge on the eastern upland areas creates 

a head gradient to the southwest across the valley. There are 

locations where upland recharge creates a groundwater divide 

and a gradient toward the eroded northeastern boundary. 

In these areas, some of the groundwater discharges to 

springs along slopes and small bluffs. The Beaver and North 

Canadian Rivers are generally gaining streams based on the 

potentiometric-surface contours, and base flow is described in 

more detail in the “Conceptual Hydrological Model” section 

of this report.
Hydrogeological Framework 19

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

2,067

2,001 2,067

2,100

2,034

1,345

1,509

1,870

1,968

1,903

2,001

1,837

1,2801,247

1,83737 1,8

2,133

1,312

1,378

1,214

1,411

1,444

1,542

1,673

1,706

1,739

1,772

1,936

1,476

1,804

2,001

2,100

1,772

1,804

1,706

1,640

1,608

1,575

2,100

2,034

1,870

2,100

2,133

2,198

2,133

2,100

2,165

2,067

Aquifer missing

Beaver-North Canadian 

 River alluvial aquifer

 (BNCA) boundary

EXPLANATION

Base of BNCA contour—Shows altitude

 of base of BNCA. Contour intervals 32

 and 33 feet. Datum is North American

 Vertical Datum of 1988

Aquifer thickness, in feet

 7 to 40

 41 to 70

 71 to 105

 106 to 174

 175 to 329

1,509

Figure 12. The approximate thickness and altitude of the base of the Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma.
20 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

Oklahoma City

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

2,000

2,080

2,200

2,100

1,380

1,600

2,140

2,120

2,100

2,080

2,060

2,120

1,400

1,440

1,420

1,820

1,460

1,840

1,480

1,340

1,520

1,660

1,540

1,640

1,860

1,560

1,500

1,680

1,760

1,900

1,740

1,880

1,720

1,800

1,700

1,920

1,940

2,060

2,000

1,980

2,020

1,960

1,320 1,300

1,620

1,580

2,040

2,080

1,580

1,240

1,260

1,280

1,360

2,140 2,220

2,260

2,240 2,180

2,080

2,060 2,040

2,000

2,020

1,980 2,040

1,780

1,380

Potentiometric contour—Shows 

 altitude at which water level would 

 have stood in tightly cased wells, 

 2012. Contour interval 20 feet. 

 Datum is North American Vertical

 Datum of 1988

Observation well

Aquifer missing 2,100

Beaver-North Canadian 

 River alluvial aquifer

 (BNCA) boundary

Groundwater-flow 

 direction

86.5

5

Approximate depth to 

 groundwater, in feet

 168

EXPLANATION

Figure 13. The Beaver-North Canadian River alluvial aquifer potentiometric surface, direction of groundwater flow, and approximate 

depth to groundwater from observations in 2012 (water-level data from 160 wells completed in the alluvial aquifer; U.S. Geological 

Survey, 2013c).
Hydrogeological Framework 21

Water levels in the Beaver-North Canadian River 

alluvial aquifer measured at observation wells not located 

close enough to groundwater-pumping wells to be affected 

by drawdown and with long-term records with at least 25 

observations were used to describe groundwater fluctuations 

and trends (U.S. Geological Survey, 2013c). Observation 

well water data are listed in table 4 with the number of 

readings, dates of first and last reading, mean depth to water, 

the change in water level from first to last reading, and the 

name used for the well on figures 1 and 14. Locations of six 

selected wells listed on table 4 are shown on figure 1, and 

time-series hydrographs of depth-to-water readings are shown 

in figure 14. The six wells with hydrographs in figure 14 are 

distributed across both reaches. Water levels in most wells 

with long-term records became shallower from 1980 to 2012, 

and some rose by more than 10 ft during that period (U.S. 

Geological Survey, 2013c). Linear trend lines on figure 14 

show that water levels generally trended upward from 1980 to 

2012, though all of the water levels dropped after 2008.

Aquifer Hydraulic Properties

Because the Beaver-North Canadian River alluvial 

aquifer is unconsolidated alluvium deposited in a fluvial 

environment, the Kh and specific yield (Sy) of this aquifer 

can be highly variable. Ryder (1996) reported that the 

Beaver-North Canadian River alluvial aquifer had a mean 

Kh of 59 feet per day (ft/d) and a maximum Kh of 160 ft/d. 

Water wells completed in the alluvium and terrace deposits 

typically yield 100–300 gallons per minute (gal/min), and 

yields range from less than 25 gal/min to more than 1,000 

gal/min in some high-capacity irrigation and municipal 

wells (Davis and Christenson, 1981; Christenson, 1983).

Table 4. Water-level depth statistics and water-level change from observation wells with multiple readings for the Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma.

[Source: U.S. Geological Survey (2013c); water-level change is the difference between the first reading and the last reading; mm, month; dd, day; yyyy, year; 

NA, not applicable; OW, observation well]

Site 

number

Number 

of readings

Date of 

first reading

(mm/dd/yyyy)

Date of 

last reading

(mm/dd/yyyy)

Reach

Mean depth 

to water 

(feet)

Standard 

deviation of 

depth to water

(feet)

Water-level 

change

(feet)

Name on 

figures 1 

and 14

353107097453701 48 04/14/1980 10/11/1995 2 8.8 2.0 4.1 NA

355724098283501 41 02/19/1980 01/14/2010 2 47.3 2.4 6.8 OW-7

360927098354701 39 02/19/1980 01/14/2010 1 16.1 2.9 8.5 NA

360600098324701 36 01/26/1981 01/16/2008 1 25.1 3.0 5.8 NA

355151098215101 34 05/28/1981 01/18/2006 2 26.0 3.3 8.1 NA

353315097521001 30 02/22/1980 01/26/2010 2 8.7 2.9 6.0 OW-8

355045098243101 30 02/19/1980 01/14/2010 2 14.1 3.6 5.8 NA

362942099320301 30 01/29/1980 01/06/2011 1 28.1 4.2 9.8 NA

353236097551801 29 02/22/1980 03/06/2009 2 18.4 2.8 -0.1 NA

361155098360801 29 03/17/1980 01/20/2010 1 15.8 3.1 9.4 OW-6

362818099103001 29 01/28/1980 01/20/2010 1 59.4 4.4 10.0 OW-3

363300099232001 29 01/31/1980 01/20/2010 1 37.0 4.8 11.0 OW-2

364118099444701 29 03/25/1980 01/14/2010 1 10.4 3.4 3.2 NA

363827099485001 28 03/25/1980 01/14/2010 1 7.3 1.3 -0.6 OW-1

364923099570301 26 03/26/1980 01/24/2006 1 21.9 2.4 3.3 NA

362728099220201 26 02/03/1981 01/17/2008 1 10.4 1.6 -5.7 NA

362325099091901 26 01/28/1980 01/11/2008 1 26.3 2.4 -1.1 NA

363844099442301 25 01/20/1982 01/14/2010 1 26.2 7.5 4.6 NA
22 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

EXPLANATION

Depth to water below land surface, 

 in feet—Location of observation

 well shown on figure 1

 Groundwater level

 Trend line

OW–8

OW–6

OW–2

OW–1

OW–7

OW–3

OW–3

OW–7

OW–2

OW–6

OW–8

OW–1

Measurement date

19801982198419861988199019921994199619982000200220042006200820102012

0

10

20

30

40

50

60

70

Depth to water below land surface, in feet

Figure 14. Long-term groundwater levels and trends from selected observation wells completed in the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma, 1980–2012.

Aquifer tests were reported at 10 sites on the BeaverNorth Canadian River alluvial aquifer by Mogg and others 

(1960), Wood and Stacy (1965), and Fox and Kizer (2009) 

(fig. 15). Tests reported by Mogg and others (1960) were 

located in the far eastern end of Reach II. The test reported 

in Fox and Kizer (2009) was an investigation into stream 

depletion due to groundwater pumping wells along the 

riverbank and was located just north of the city of El Reno 

in Reach II. Aquifer tests reported in Wood and Stacy 

(1965) were from Woodward County clustered just south 

of Fort Supply Lake in Reach I. Values of Kh from published 

aquifer tests conducted in the study area ranged from 51 to 

223 ft/d, and Sy ranged from 0.10 to 0.24, as listed in table 5.

Estimated mean Kh from lithologic borehole logs 

provided an initial distribution of Kh to be adjusted during 

calibration of the numerical groundwater-flow models. 

The mean Kh was estimated by assigning a Kh value to 

lithologic classes described for intervals in borehole logs, 

and calculating the mean, weighted by the thickness of each 

interval. To assign Kh values to intervals, the Kh for lithologic 

texture classes of the Beaver-North Canadian River alluvial 

aquifer was estimated by using published values. 

The greatest number of aquifer-test results for the 

Beaver-North Canadian River alluvial aquifer was compiled 

in Mogg and others (1960), which included a sieve analysis 

of 189 sediment samples from 34 boreholes in Canadian 

County. Mogg and others (1960) reported the measured 

coefficient of permeability in gallons per day per square foot 

for each of the sieve samples. The coefficient of permeability 

was converted to Kh in feet per day by multiplying by 0.134 

(Fetter, 1994). An approximate linear relation between Kh 

and texture was then calculated and used to assign a Kh value 

to various categories of lithology (table 6). For this report, 

lithologic descriptions in borehole logs (Oklahoma Water 

Resources Board, 2013) were categorized to a textural class 

and assigned the associated Kh from table 6. Thicknessweighted mean Kh at each borehole location and locations 

where an aquifer test had been performed were interpolated 

across the Beaver-North Canadian River alluvial aquifer by 

using the inverse distance weighted method (Esri, Inc., 2015). 

Because the alluvial aquifer contains beds of silt and clay, the 

vertical hydraulic conductivity was estimated to be one-tenth 

of the Kh.
Hydrogeological Framework 23

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

162

191

78 136

180

152

51

95

61

162

191

223

78 136

180

152

51

95

61

EXPLANATION

Beaver-North Canadian River alluvial

 aquifer (BNCA) boundary

Aquifer test site with hydraulic conductivity,

 in feet per day, by published source

 Mogg and others (1960)

 Wood and Stacy (1965)

 Fox and Kizer (2009)

Estimated horizontal hydraulic

 conductivity, in feet per day

6.2 to 44.2

44.3 to 75.0

75.1 to 115.9

116.0 to 184.6

184.7 to 278.9 95

78

191

Figure 15. Locations of published aquifer tests and calibrated horizontal hydraulic conductivity from numerical flow models for the 

Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.
24 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Table 5. Estimated hydraulic conductivity and specific yield of the Beaver-North Canadian River alluvial aquifer from published aquifer 

tests.

[NA, not available]

Site number Unit Hydraulic conductivity 

(feet per day)

Specific 

yield Source

NA Alluvium 95 0.24 Fox and Kizer (2009)

13N-08W-24 CCD Alluvium 162 0.10 Mogg and others (1960)

12N-05W-36 DBB Alluvium 191 0.14 Mogg and others (1960)

22N-19W-35 CCA 4 Alluvium 223 NA Wood and Stacy (1965)

23N-22W-22 DCD1 Alluvium 61 NA Wood and Stacy (1965)

23N-18W-30 DDC 1 Terrace 78 NA Wood and Stacy (1965)

23N-19W-23 CBD 1 Terrace 136 NA Wood and Stacy (1965)

23N-19W-28 ACA 1 Terrace 180 NA Wood and Stacy (1965)

23N-20W-07 DBD 5 Terrace 152 NA Wood and Stacy (1965)

24N-20W-06 CDB 1 Terrace 51 NA Wood and Stacy (1965)

Table 6. Horizontal hydraulic conductivity assigned to textural 

classes of sediments in the Beaver-North Canadian River alluvial 

aquifer, northwestern Oklahoma.

[Data from Fetter (1994)]

Textural class Hydraulic conductivity 

(feet per day)

Gravel 280

Very coarse sand 175

Coarse sand 90

Medium sand 20

Fine sand and silt 0.01

Clay 0.00001

Because little information was available on Sy from 

published aquifer tests in the Beaver-North Canadian River 

alluvial aquifer, Sy for each borehole location was calculated 

from estimated mean Kh. Horizontal hydraulic conductivity 

and Sy for textural classes were taken from ranges published 

in Fetter (1994) and used to caculate a logarithmic regression 

to estimate Sy for other values of Kh. The coarsest sediment 

in the Beaver-North Canadian alluvial aquifer was assumed 

to be medium-grained gravel with a Kh of 280 ft/d and was 

assigned an Sy of 0.27. The finest grained texture likely 

found in the aquifer was assumed to be clay with a Kh of 

0.00001 ft/d and was assigned an Sy of 0.07. Medium-grained 

sand with a Kh of 50 ft/d was assigned an Sy of 0.26. A 

logarithmic (ln) regression with a correlation coefficient of 

0.998 was determined by using the three textural classes using 

equation 1.

Sy = a ln(Kh) + b (1)

where 

a and b are calculated regression coefficients. 

The best-fit logarithmic regression coefficients were found, 

and the regression was determined to be

Sy = 0.0119 ln(Kh) + 0.2078 (2)

By using this method, the mean Sy in Reach I was 0.16, and 

the mean Sy in Reach II was 0.2. As with Kh, the derived Sy 

at each location was an estimate and an initial value that was 

adjusted during numerical-model calibration. 

The Kh of the bedrock underlying the Beaver-North 

Canadian River alluvial aquifer was estimated by using 

lithologic descriptions of geological units from Heran and 

others (2003) and approximate Kh values from Fetter (1994) 

for the lithologic type (table 7). Bedrock Kh values were 

generalized and assumed to be homogeneous within each 

geologic unit. No direct measurements of the bedrock Kh 

have been made. Storage parameters for Permian bedrock 

units were generalized to 0.1 for Sy and 0.0001 for specific 

storage. Specific storage is a parameter that is used in confined 

conditions and is required for the numerical groundwater-flow 

model. 
Hydrogeological Framework 25

Table 7. Texture and horizontal hydraulic conductivity assigned to bedrock units underlying the Beaver-North Canadian River alluvial 

aquifer, northwestern Oklahoma.

Unit Lithology 

(Heran and others, 2003)

Hydraulic conductivity from Fetter (1994)

(feet per day)

Ogallala Formation Sandstone, clay, and caliche 3.5

Cloud Chief Formation Shale, siltstone 0.0001

Rush Springs Formation Fine-grained sandstone with siltstone, gypsum 0.9

Marlow Formation Fine-grained sandstone and siltstone, gypsum 0.2

Dog Creek Shale Shale and siltstone 0.0001

Blaine Formation Gypsum and dolomite 0.01

Chickasha Formation Mudstone, conglomerate, and silty shale 0.001

Duncan Sandstone Fine-grained sandstone with mudstone 0.1

Bison Formation Shale 0.0001

Conceptual Flow Model

The conceptual flow model of the Beaver-North Canadian 

River alluvial aquifer hydrologic system is a schematic 

description of the boundary conditions and related flows that 

compose the aquifer flow budget. The conceptual flow model 

with the hydrogeologic framework was used to conceptualize, 

design, and construct the numerical groundwater-flow models.

Flow volumes for the major boundaries of the BeaverNorth Canadian River alluvial aquifer hydrologic system were 

estimated to produce an approximate mean annual budget 

for the Beaver-North Canadian River alluvial aquifer during 

the period 1980–2011. Boundary categories estimated for the 

aquifer included surface recharge, stream and lake interactions 

with the aquifer, human water use, discharge to springs and 

seeps, and ET in each reach. This flow budget is generalized 

because of available data, and a more detailed estimate of the 

flow budget is quantified by the numerical groundwater-flow 

models.

Hydrological Boundaries

Hydrological boundaries are defined as locations 

through which a substantial amount of water moves—or is 

not able to move in the case of a no-flow boundary—to or 

from the groundwater system and are used to quantify and 

categorize groundwater flows. Flow boundaries are of three 

types: specified-flow boundaries, head-dependent boundaries, 

and constant-head boundaries. Specified-flow boundaries 

include wells and recharge through which a continuous flow 

passes during a simulation stress period. Flow through headdependent boundaries is a function of the relative head at 

the boundary and the adjacent aquifer and the conductance 

of the boundary. Head-dependent boundaries in the BeaverNorth Canadian River alluvial aquifer include streams, lakes, 

lateral flow from adjacent units, and springs. Constant-head 

boundaries, through which a flow passes based on an assigned 

head, are not used in the models described in this report.

The most areally extensive boundary in the BeaverNorth Canadian River alluvial aquifer is the specified-flow 

boundary at the land surface, through which a portion of 

precipitation flows to the aquifer as groundwater recharge and 

water that is taken up and transpired to the atmosphere from 

groundwater by vegetation if the water table intersects the 

root zone. The second most extensive boundary is the base of 

the alluvial aquifer through which water can move to or from 

the underlying bedrock. The channel of the Beaver and North 

Canadian Rivers is a head-dependent flow boundary where 

groundwater and streamflow interact and are governed by 

the conductance of the streambed. Flow through the headdependent flow boundary consisting of lakebeds was estimated 

to be much less than flow to the Beaver and North Canadian 

Rivers and was included in the budget for streams. Point 

location specified-flow boundaries included groundwaterpumping wells shown in figure 2 and springs along the eastern 

margin of the aquifer. 

Lake seepage in the study area has not been studied 

or measured. Although the U.S. Army Corps of Engineers 

has collected and calculated daily flows for Canton and 

Fort Supply Lakes (U.S. Army Corps of Engineers, 2013), 

groundwater flow was not separated from runoff or stream 

inflow. As shown in the potentiometric surface in figure 13, 

there was a groundwater gradient toward the lakes and it 

was assumed that groundwater flowed into the lakes, but 

groundwater flows to the lakes were not estimated for the 

conceptual flow model.
26 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

The groundwater flow between the Beaver-North 

Canadian River alluvial aquifer and bedrock is not estimated 

for the conceptual flow model. In the northwestern part of 

Reach I, the aquifer is connected to the Ogallala Formation of 

the High Plains aquifer both in the Beaver and North Canadian 

River Valleys and along the western margin (fig. 11). Because 

of a lack of local hydrogeologic data, groundwater flow from 

the Ogallala Formation or underlying units could not be 

estimated for the conceptual model. 

In the northwestern parts of the study area, the 

Beaver-North Canadian River alluvial aquifer overlies the 

Rush Springs Formation, although in the absence of local 

groundwater pumping, groundwater flow to the Beaver-North 

Canadian River alluvial aquifer would require a vertical, 

upward head gradient and is assumed to be unsubstantial, 

as reported in Christenson (1983). There is the potential for 

water loss from the Beaver-North Canadian River alluvial 

aquifer to the Blaine Formation in the southeastern parts of 

the aquifer because of saline and gypsum karst features in the 

bedrock (Morton, 1980); however, these features have not 

been mapped, nor have any estimates of flow in that area been 

made.

Stream Base Flow

Stream base flow is defined in Barlow and Leake 

(2012) as the flow of groundwater into streams through the 

streambed. A gaining stream receives base flow, and a losing 

stream loses streamflow through infiltration to an aquifer. 

Base flow and local runoff are the sources of most of the 

Beaver and North Canadian Rivers streamflow, with inflows 

from sources outside the aquifer from the west including Wolf 

Creek (fig. 1) and streamflow from the Beaver River upstream 

from the Beaver-North Canadian River alluvial aquifer. There 

are no known tributaries that flow over the Beaver-North 

Canadian River alluvial aquifer from the east. A substantial 

amount of the flow in Reach II of the North Canadian River 

was composed of streamflow released from Canton Lake (U.S. 

Army Corps of Engineers, 2013).

To quantify the stream base flow, seepage-run 

measurements and hydrograph (base flow)-separation methods 

were used. Base-flow separation uses streamflow hydrographs 

to estimate the total base flow and base-flow index (BFI), 

or the ratio of base flow to total streamflow. Seepage runs 

were used to characterize streamflow and estimate base 

flow at one point in time. A seepage run isolates base flow 

by measuring streamflow approximately simultaneously 

at different locations in a drainage basin at a time when 

streams are at low flow, ET is at a minimum because plants 

are dormant, and recent precipitation is minimal, so runoff is 

very low, if not zero. Base flow is estimated during a seepage 

run by calculating the difference between the streamflow 

measurement at the upstream end of a reach (inflow) and the 

streamflow measurement at the downstream end of a reach 

(outflow). Inflow from tributaries is accounted for so that 

only the gain or loss of streamflow along the stream reach is 

measured.

Base-flow separation was performed by using the 

BFI computer program (Wahl and Wahl, 2007) that uses 

hydrograph-recession records. The BFI computer program 

uses a specified window of days that covers the duration of 

storm-runoff peaks to separate base flow from runoff by using 

hydrograph-recession analysis. Because of streamflow control 

by Canton Lake, base-flow separation was not performed for 

Reach II.

Reach I Seepage Runs

A seepage run reported in Davis and Christenson (1981) 

was conducted from March 12 to 14, 1979, with 18 synoptic 

streamflow measurements along the Beaver and North 

Canadian Rivers and 13 tributaries (fig. 16). The first upstream 

reach was considered to be losing because the total inflow 

of 11.8 ft3/s (9.5 ft3/s from Kiowa Creek and 2.3 ft3/s from 

upstream) was much greater than the outflow of 2.8 ft3/s. The 

net difference was a loss of 9.0 ft3/s over about 1 mi of channel 

between Kiowa Creek and the next measurement (fig. 16). 

Beaver and North Canadian Rivers reaches between Kiowa 

Creek and Persimmon Creek were generally gaining except 

for the reaches at Clear and Otter Creeks. The only other 

losing reach was at Bent and Deep Creeks, which lost 2.0 ft3/s 

over about 10 mi. Wolf Creek below Fort Supply Lake was 

considered to be gaining, although it was not known whether 

the flow measured near the confluence with the Beaver River 

was base flow or included flow released from Fort Supply 

Lake because release data were not available for the time the 

seepage run took place.

The streamflow in the Beaver and North Canadian Rivers 

during the 1979 seepage run by stream reach with distance 

downstream is shown on figure 17 as the total observed 

streamflow including tributaries (solid red line) and the 

cumulative streamflow gain with tributary input subtracted 

(dashed red line). The slope of the dashed line indicates 

whether it is gaining (positive slope) or losing (negative 

slope). The cumulative base flow for the 1979 seepage run 

alternated between losing and gaining, reflecting flows in the 

reaches shown in figure 16 until just past 40 mi where the river 

became a gaining stream. At approximately 70 mi downstream 

from the northwestern aquifer boundary, the accumulated 

base flow surpassed the streamflow that was lost, and at the 

end of Reach I, the accumulated streamflow gain was 31 ft3/s 

as shown at the downstream end of the red dashed line in 

figure 17.
Hydrogeological Framework 27

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

0 5 10 15 20 MILES

0 5 10 15 20 KILOMETERS

OKLAHOMA

BNCA Reach I area

EXPLANATION

Seepage run streamflow, in cubic

 feet per second—Values in black

 are streamflow measurements for

 Beaver and North Canadian Rivers. 

 Values in brown are streamflow 

 values for tributaries (Davis and 

 Christenson, 1981)

 0 to 2

 2.1 to 5

 5.1 to 8

 8.1 to 15

 15.1 to 65

Calculated stream base flow from the 

 1979 seepage run for Reach I, in 

 cubic feet per second (Davis and 

 Christenson, 1981)

 –9

 –8 to –2

 –1 to 0

 1 to 5

 6 to 10

Beaver-North Canadian River alluvial

 aquifer (BNCA) boundary

Gaining

Losing

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

Canton

Lake

Spring Creek

Woodward Creek

Sand

Creek

Boggy

Creek Indian

 Creek

Deep Creek

Persimmon Creek

Wolf Creek

Bent

 Creek

Clear

Creek

Seiling

Creek

Fort Supply

Lake

Beaver River

North Canadian River Otter Creek

Kiowa

Creek

0.7

1.3

0.3

0.2

0.5

6.1

0.9

9.5

5.2

0.6

1.6

4.7

0.1

0.7

64.6 57.2

51.7

48.4

25.6

24.4 16.5

13.1

11

6.4 6.3

7.6

5.2

4.7

2.8

2.3

35.8

14.5

35.8

2.8

5.2

14.5

ELLIS COUNTY DEWEY COUNTY

WOODWARD COUNTY

WOODS COUNTY

HARPER COUNTY

MAJOR COUNTY

BLAINE

COUNTY

100° 99°45' 99°30' 99°15' 99° 98°45'

37°

36°45'

36°30'

36°15'

36°

Canton

Seiling

Woodward

Figure 16. Streamflow measurements and calculated base flow from the 1979 seepage run in Davis and Christenson (1981) for Reach I 

of the Beaver and North Canadian Rivers, northwestern Oklahoma.
28 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Observed streamflow, by seepage run

 1979 (Davis and Christenson, 1981)

 2012

Cumulative streamflow gain, by seepage run

 1979 (Davis and Christenson, 1981)

 2012

Tributary contributions, by seepage run

 1979 (Davis and Christenson, 1981)

 2012

EXPLANATION

Wolf Creek

Streamflow, in cubic feet per second

0

10

20

30

40

50

60

70

-10

0 20 40 60 80 100 120 140

Stream channel distance, in miles

Figure 17. Cumulative streamflow and streamflow corrected for tributary inflow with distance downstream from the upstream limit of 

the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma, by stream reach in the Beaver and North Canadian Rivers, 

from the 1979 (Davis and Christenson, 1981) and 2012 seepage runs. 

On February 21–22, 2012, a series of streamflow 

measurements were made for a seepage run along the Beaver 

and North Canadian Rivers and contributing tributaries in 

Reach I similar to the measurements described in Davis 

and Christenson (1981). Influence from surface runoff was 

estimated to be minimal because the highest precipitation 

amount recorded during the 10 days preceding the seepage run 

was less than 0.20 in. at the Seiling streamflow-gaging station 

(07238000), and streamflows during that period were constant 

or very slightly declining. Comparative statistics in table 8 

show that streamflow measurements for this seepage run were 

made when streamflows were less than the minimum 7-day, 

2-year recurrence interval at the Woodward streamflow-gaging 

station and were slightly less than the minimum 7-day, 2-year 

recurrence interval flow conditions at the Seiling streamflowgaging station. At both stations, the daily mean streamflows 

during the seepage run were substantially less than the 

historical median February streamflow. For these reasons, 

streamflow in the Beaver and North Canadian Rivers and all 

contributing tributaries was considered to be mostly, if not 

entirely, composed of base flow at the time of the seepage 

run.

There were 14 streamflow measurements made along 

the Beaver and North Canadian Rivers and 11 measurements 

made on 10 tributaries, including 2 on Wolf Creek for the 2012 

seepage run (fig. 18). Tributary streamflow was measured a 

short distance upstream from the confluence with the Beaver 

or North Canadian Rivers, and in these instances, river-mile 

distances were reported relative to the confluence. The two 

measurements on Wolf Creek were separated by Fort Supply 

Lake and were not used for base-flow calculations for Wolf 

Creek.
Hydrogeological Framework 29

Table 8. Comparative streamflow statistics for selected U.S. Geological Survey streamflow-gaging stations during the 2012 seepage 

run, North Canadian River, northwestern Oklahoma.

[All flow in cubic feet per second]

Streamflowgaging station

+

Daily mean flow 

Feb. 21–22, 2012

*February flow statistics *Minimum 7-day, 

2-year flow 

Nov. 1–Mar. 31 Maximum Median Minimum

07237500 17, 17 246 79.7 12.6 19.8

07238000 60, 57 360 118 36.7 43.5

+

U.S. Geological Survey (2013d).

*

Lewis and Esralew (2009).

At the northwestern edge of the Beaver-North Canadian 

River alluvial aquifer, the Beaver River was dry at the time 

of the seepage run and received 7.8 ft3/s of streamflow from 

Kiowa Creek (fig. 18). The first stream reach had an outflow 

of 1.5 ft3/s and thus lost 6.3 ft3/s over that reach. The next two 

downstream streamflow measurements gained streamflow, but 

after removing the inflow from Clear and Otter Creeks, the 

downstream reaches were losing until just upstream from the 

confluence of Wolf Creek. All of the reaches from Wolf Creek 

to Canton Lake were gaining base flow, even when corrected 

for substantial inflow from tributaries (figs. 17 and 18). The 

total base flow determined from the total downstream increase 

in flow measured during the 2012 seepage run adjusted for 

tributary inflow was 28.0 ft3/s. Streamflow measured at the 

Seiling streamflow-gaging station, including tributary input, 

was 65.0 ft3/s.

Comparison of streamflow data collected during the 

1979 and 2012 seepage runs indicates similar streamflow 

characteristics (fig. 17). The seepage runs indicate that the 

Beaver and North Canadian Rivers and Wolf Creek were 

generally gaining streams with losing sections upstream from 

Wolf Creek. Tributary streamflows were comparable between 

the two seepage runs with the exception of streamflow in 

Persimmon Creek, which in 2012 was nearly twice that 

measured in 1979. At least half of the total downstream 

increase in streamflow measured in the Beaver and North 

Canadian Rivers in Reach I during both seepage runs was 

from tributaries, with 33.5 ft3

/s in 1979 and 38.5 ft3/s in 2012. 

The total base flow calculated for Reach I was 31.1 ft3/s in 

1979 and 26.6 ft3/s in 2012; the mean total base flow for Reach 

I from seepage runs was 28.8 ft3/s. The streamflow at the 

Seiling streamflow-gaging station was nearly identical in both 

seepage run measurements, 64.6 ft3/s in 1979 and 65.0 ft3/s in 

2012.

Reach I Base-Flow Separation

Daily streamflow data were available for the entire period 

of study at the Seiling streamflow-gaging station, which is 

located just upstream from Canton Lake (fig. 1). These data 

were used in the BFI computer program (Wahl and Wahl, 

2007) to calculate an annual BFI (total streamflow/total base 

flow) and total base-flow volume. The window for storm 

hydrograph duration—the mean length of a runoff peak from a 

precipitation event—was estimated at 6 days. The mean BFI, 

or the proportion of streamflow that originates as base flow for 

1980–2011, was calculated to be 0.63, which was similar to 

estimates in Esralew and Lewis (2010). The mean annual base 

flow for Reach I was calculated to be approximately 69,000 

acre-ft (table 9).

Reach II Seepage Run 

Christenson (1983) described a seepage run in the 

North Canadian River south of Canton Lake conducted 

during January 1981 that measured flow at various locations 

including near USGS streamflow-gaging stations (fig. 19). 

Tributary flow was not considered a substantial component 

in Reach II and was not measured (Christenson, 1983). 

An additional seepage run was not conducted for the study 

described in this report.

During the seepage run, Canton Lake was releasing 

6.1 ft3/s in streamflow into the North Canadian River, and 

in nearly every reach, streamflow measurements increased 

downstream, although base flow was variable among reaches. 

In total, the streamflow in the North Canadian River in 

Reach II increased from 6.1 to 20.3 ft3/s (fig. 19) and thus 

gained 14.2 ft3/s in streamflow between Canton Dam and 

the Lake Hefner Canal diversion; only one segment between 

Watonga and Calumet lost streamflow (0.4 ft3/s) to the 

Beaver-North Canadian River alluvial aquifer (fig. 19). The 

greatest gains were 4.8 ft3/s in streamflow measured in the 

first reach below Canton Lake and 3.0 ft3/s of streamflow 

measured between the streamflow-gaging station near Calumet 

(07239450) and the streamflow-gaging station near El Reno 

(07239500).
30 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

0 5 10 15 20 MILES

0 5 10 15 20 KILOMETERS

OKLAHOMA

BNCA Reach I area EXPLANATION

Seepage run streamflow, in cubic

 feet per second—Values in black

 are streamflow measurements for

 Beaver and North Canadian Rivers. 

 Values in brown are streamflow 

 values for tributaries (Christenson,

 1983)

 Less than 5.1

 5.1 to 20

 20.1 to 40

 40.1 to 65

Calculated stream base flow from the 

 2012 seepage run for Reach I, in cubic

 feet per second (Christenson, 1983)

 –6

 –5 to –2

 –1 to 0

 1 to 2

 3 to 5

 6 to 25

Beaver-North Canadian River alluvial

 aquifer (BNCA) boundary

Gaining

Losing

4.8

41.5

5.1

20.7

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

Canton

Lake

Spring Creek

Woodward Creek

Sand

Creek

Boggy

Creek Indian

 Creek

Deep Creek

Persimmon Creek

Wolf Creek

Bent

 Creek

Clear

Creek

Seiling

Creek

Fort Supply

Lake

Beaver River

North Canadian River Otter Creek

Kiowa

Creek

7.8

2.8

0.6

41.5

1.3

0.6

0.8

0.3

5.4

14.1

4.8

0

1.5

3.3

4.2

6.8

3.8 2

5.1

9.3

12.2 17.5

20.7

31.5

65

ELLIS COUNTY DEWEY COUNTY

WOODWARD COUNTY

WOODS COUNTY

HARPER COUNTY

MAJOR COUNTY

BLAINE

COUNTY

100° 99°45' 99°30' 99°15' 99° 98°45'

37°

36°45'

36°30'

36°15'

36°

Canton

Seiling

Woodward

Figure 18. Streamflow measurements and calculated base flow from the 2012 seepage run, Reach I of the Beaver and North Canadian 

Rivers, northwestern Oklahoma.
Hydrogeological Framework 31

Table 9. Conceptual flow model estimated annual hydrological budget for the Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma.

[All units in acre-feet per year; positive values are volumes to the aquifer, and negative values are leaving the aquifer; NA, not applicable]

Budget category Reach I Reach II Total

Inflow

Recharge 136,400 82,400 218,800

Outflow

Evapotranspiration and springs 53,400 NA NA

Base flow to streams 69,000 NA NA

Groundwater pumping 14,000 12,000 26,000

Total outflow 136,400 82,400 218,800

Groundwater Recharge

Groundwater recharge is the primary source of inflow to 

the Beaver-North Canadian River alluvial aquifer. Recharge 

was estimated both areally across the aquifer by using a soilwater-balance (SWB) model and at two locations by using 

a water-level fluctuation (WTF) method. The methods used 

provided spatially distributed transient recharge estimates on 

the basis of physical and climatologic variables, and the point 

measurements provided estimates of the ratio of precipitation 

that enters the groundwater system as recharge.

Soil-Water-Balance Model

To estimate transient groundwater recharge across the 

Beaver-North Canadian River alluvial aquifer, the SWB code 

of Westenbroek and others (2010) was used. The SWB code 

used grids of landscape and climate data with grid cells 1,640 

ft by 1,640 ft to provide estimates of spatially distributed 

deep percolation through the soil profile. Deep percolation 

could become groundwater recharge and is referred to in this 

report as “recharge” because the aquifer is unconfined. The 

SWB-calculated recharge consists of recharge arrays that are 

a starting point for calibrating groundwater-flow models, as 

shown in Stanton and others (2012).

The SWB code tracks soil-water content within the soil 

root zone and inflows (percolation from the land surface due 

to precipitation and runoff from adjacent areas) and outflows 

(plant interception and ET) on daily time steps. Plant ET was 

calculated in the SWB code by using the Hargreaves and 

Samani (1985) method based on the land-cover vegetation. 

Recharge is the surplus soil water that infiltrates into the soil 

profile when the soil in the root zone is fully saturated.

A simple runoff model is used in the SWB code to 

route runoff between cells by using a grid of land-surface 

flow direction derived from a digital elevation model (DEM) 

(U.S. Geological Survey, 2013a). The amount of water that 

infiltrates into the soil profile is calculated by using the soil 

runoff curve number and hydrologic soil group from soil 

survey geospatial data (Natural Resource Conservation 

Service, 2013). The total soil-water storage capacity is 

calculated by using the available water capacity from soil data 

(Natural Resource Conservation Service, 2013) and the rootzone depth determined from the land-cover vegetation and soil 

type in each cell (Thornthwaite and Mather, 1957).

The SWB code used grids of daily precipitation and 

maximum and minimum temperature interpolated from 173 

weather stations located on and in the general area of the 

Beaver-North Canadian River alluvial aquifer (National 

Climatic Data Center, 2013). Weather stations within 

a rectangle bounded by 35.1–37.2 degrees latitude and 

100.4–97.3 degrees west longitude were used, and most are 

shown in figure 5. Because the period of record varies for 

the stations used, the number of stations with temperature 

and precipitation data on any particular day varied during the 

period of study. In 1980, the mean number of stations with 

readings on a given day was 42, and in 2011, the mean number 

of stations with readings was 115. Daily grids of precipitation 

and high and low temperature were interpolated from point 

data by using the inverse distance weighted method (Esri, Inc., 

2015). 

Recharge estimated by the SWB model is spatially 

variable because soil properties, flow direction, land cover, 

precipitation, and temperature are spatially variable. Important 

assumptions of the SWB code are that the root zone is above 

the water table and that the only source of water for the 

soil profile is water percolating from the land surface. In 

parts of the Beaver-North Canadian River alluvial aquifer, 

particularly near lakes and streams, plant roots may reach the 

water table. The SWB model calculates the potential ET and 

then limits the actual ET to the available water in the soil on 

the basis of soil moisture content; however, if groundwater 

is shallow enough to intersect the root zone such that plants 

can access it, the actual ET calculated by the SWB model is 

underestimated, and though the recharge may be accurate, 

there is an additional sink to the groundwater system. Thus, 

there may be an additional loss via ET that is not accounted 

for—as much as the difference between the actual ET and 

the potential ET calculated by the SWB model, which causes 

recharge to be overestimated. This topic is described further 

in the “Numerical Groundwater-Flow Model” section of this 

report.
32 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Base from U.S. Geological Survey digital data Aquifer boundary modified from Oklahoma Water Resources Board (2012)

Universal Transverse Mercator, zone 14

North American Datum of 1983 0 5 10 15

0 5 10 15 20 KILOMETERS

20 MILES

OKLAHOMA

BNCA Reach II area

Change in streamflow below

 Canton Lake, in cubic feet

 per second—Values are 

 streamflow measurements

 for Beaver and North Canadian

 Rivers (Christenson, 1983)

 0

 0.1 to 5.9

 6.0 to 9.5

 9.6 to 12.5

 12.6 to 14.2

Calculated stream base flow from the 

 1981 seepage run for Reach II, in cubic

 feet per second (Christenson, 1983)

 –0.4

 –0.3 to 0

 0.1 to 1.5

 1.6 to 3.0

 3.1 to 4.8

Beaver-North Canadian River alluvial

 aquifer (BNCA) boundary

Streamflow-gaging station and 

07239500 number

15.6

20.3

18.6

6.1

10.9

Gaining

Losing

EXPLANATION

Canton

Lake

Lake Overholser

North Canadian River

CANADIAN COUNTY

CADDO COUNTY

KINGFISHER COUNTY

BLAINE COUNTY

LOGAN COUNTY OKLAHOM

A COUNTY

07238500

07239000

07239300

07239450

07239500

07239700

07240200

Watonga

Canton

Calumet

Yukon

El Reno

36°

35°45'

35°30'

98°30' 98°15' 98° 97°45'

15.6

14.3

6.1

10.9

12

14.7

18.6 20.1

20.3

Figure 19. Streamflow measurements and calculated base flow from the 1981 seepage run for Reach II of the North Canadian River, 

from Christenson (1983).
Hydrogeological Framework 33

The SWB recharge calculated for the Beaver-North 

Canadian River alluvial aquifer over the period of study 

was summed to produce an estimate for total recharge over 

the study period and for each year. Grids of recharge for 

each month of the model period were used for numerical 

groundwater-flow model inputs. A map of the spatially 

distributed mean annual recharge in inches calculated by the 

SWB code is shown in figure 20. Mean annual recharge was 

less in the northwestern part of the aquifer and is concentrated 

where runoff causes additional water to collect.

Recharge is highly temporally variable as precipitation 

changes season to season and year to year. Particularly in 

the drier western Reach I, recharge is sensitive to changes 

in precipitation because the soil profile must become fully 

saturated before excess infiltration can become recharge. A 

graph of the total annual recharge and mean annual recharge 

(218,800 acre-ft) to the Beaver-North Canadian River alluvial 

aquifer for the period of study as estimated by using the SWB 

code is shown in figure 21. There were no prolonged periods 

of hydrologic drought with unusually low precipitation and 

recharge during this time period, although 1980–81 were the 

last 2 years of the 1976–81 drought, and 2011 was the ninth 

driest year statewide in Oklahoma since 1925 (Shivers and 

Andrews, 2013). The lowest calculated recharge years were 

2003 and 2006, which were 28 and 30 percent of the mean 

annual SWB recharge, respectively. The longest period of 

negative departure from the mean recharge was 1988–91, 

during which no year reached the study period mean recharge. 

The years with the greatest recharge were 1985, 2004, and 

2007, in which 165, 160, and 195 percent of the mean annual 

SWB recharge were estimated to reach the water table, 

respectively. There were two periods with consistently positive 

departures from the mean recharge, 1985–87 and 1997–2001 

(fig. 21).

A sensitivity analysis was performed by varying the two 

parameters that the analysis is most sensitive to, precipitation 

and root-zone depth (Westenbroek and others, 2010; Stanton 

and others, 2011), independently by 10 percent. Available 

water capacity was not used in the sensitivity analysis because 

it directly correlates with root-zone depth. A 10-percent 

increase in daily precipitation applied during the model 

run resulted in a 26-percent increase in total recharge, and 

a 10-percent decrease in precipitation caused a 23-percent 

decrease in recharge (fig. 22). Recharge was sensitive to 

root-zone depth as well. Recharge decreased 9 percent with a 

10-percent increase in root-zone depth and increased 8 percent 

with a 10-percent decrease in root-zone depth.

The importance of the sensitivity analysis is that 

the precipitation and root-zone depth are generalized and 

interpolated across the model area. Precipitation measurements 

have measurement and the interpolation error. Root-zone 

depth is estimated for each land-use type and soil type, and 

although the land-use types and soils are not highly variable, 

with most of the area covered by grassland and sandy soil, 

local small-scale variation is not represented in 1,640-ft square 

grid cells. 

The estimated mean annual recharge from the SWB 

model was 136,400 acre-ft in Reach I and 82,400 acre-ft in 

Reach II, for a total of 218,800 acre-ft. The total estimated 

recharge from 1980 to 2011 was approximately 4,350 

thousand acre-ft for Reach I and 2,600 thousand acre-ft for 

Reach II. It should be noted that Reach I typically receives 

less precipitation than Reach II, and the mean annual recharge 

was 0.25 acre-feet per acre (acre-ft/acre) in Reach I and 0.34 

acre-ft/acre in Reach II. The total recharge flow in Reach I 

was greater than in Reach II because the area of Reach I is 

substantially larger.

Local Recharge Estimation

Groundwater recharge from precipitation was estimated 

at two locations in Reach I by using the WTF method from 

Healy and Cook (2002). Concurrent readings of water levels 

from observation wells and precipitation from the Woodward 

and Seiling streamflow-gaging stations (fig. 1) were 

analyzed (U.S. Geological Survey, 2013c, d). Observation 

wells closest to streamflow-gaging stations were selected 

and continuous readings of groundwater head recorded. 

Observation wells at these sites included observation well 

OW-4 (USGS site number 362726099230401) near the 

Woodward streamflow-gaging station and observation well 

OW-5 (361145098560401) near the Seiling streamflowgaging station (fig. 1). The two observation well locations 

are subsequently referred to as the “Woodward” and 

“Seiling” sites. Instruments in OW-4 and OW-5 recorded 

the groundwater level every 30 minutes for parts of 2012 

and 2013, and the mean daily water level at both sites was 

compared with daily precipitation measured at respective 

streamflow-gaging stations. 

The WTF method uses the change in the groundwater 

head related to a precipitation event in shallow, unconfined 

aquifers, multiplied by the Sy of the aquifer to calculate the 

amount of water from that precipitation event that became 

groundwater recharge. If the groundwater head was rising or 

dropping previous to the precipitation event, that trend was 

extrapolated below the groundwater-head peak to estimate the 

rise in groundwater head as a peak superimposed on the trend.
34 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

EXPLANATION

Aquifer missing

Beaver-North Canadian River 

 alluvial aquifer (BNCA) 

 boundary

Mean annual recharge, in

 inches per year, 1980–2011

 0 to 2.3

 2.4 to 5.0

 5.1 to 10.6

 10.7 to 21.6

 21.7 to 50.4

Figure 20. Mean annual groundwater recharge from 1980 to 2011 calculated by using the soil-water-balance code of Westenbroek and 

others (2010) for the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.
Hydrogeological Framework 35

EXPLANATION

Annual mean recharge

Mean annual recharge

218,800 acre-feet

Year

1980

1981

1982

1983

1984

1985

1986

1987

1988

1989

1990

1991

1992

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

2005

2006

2007

2008

2009

2010

2011

0

Total annual groundwater recharge, in acre-feet

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

50,000

Figure 21. Total annual groundwater recharge 1980–2011 calculated by using the soil-water-balance model for the Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma. 

Precipitation

Root-zone depth

EXPLANATION

-15 -10 -5 0 5 10 15

Percentage change in parameter

Percentage change in recharge

-30

-20

-10

10

20

30

0

Figure 22. Sensitivity of recharge calculated by the soil-water-balance model (Westenbroek and others, 2010) for the Beaver-North 

Canadian alluvial aquifer to changes in precipitation and root-zone depth.
36 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

The WTF method is approximate and relies on infiltration 

of precipitation reaching the water table within several days, 

and the water level is not affected by other processes such as 

plant uptake, pumping wells, surface runoff, or infiltration 

from surface water. After precipitation takes place, infiltration 

that becomes groundwater causes the water level in a well to 

rise. The water level then drops as groundwater is redistributed 

or is removed from the aquifer by other processes. Thus, the 

aquifer must be unconfined, the water table must be within 

a few feet of the land surface, and the topsoil and aquifer 

material must be permeable enough so that the infiltration flow 

rate is greater than the rate at which the groundwater dissipates 

or flows to groundwater sinks for this analysis. Because the 

records of water-level observations did not include a full 

calendar year, the WTF analyses included the water year 2013 

(October 2012 through September 2013). Recharge estimated 

by using the WTF method could not be directly compared 

to the SWB model because the SWB model was only run 

through 2011, but the mean percentage of precipitation that 

was estimated to become recharge in the SWB model was 

compared to percentages estimated for the Woodward and 

Seiling sites.

Woodward Site

The Woodward site is located at observation well OW-4 

(fig. 1), which was 0.7 mi east of the North Canadian River 

and just over 6 mi upstream from the Woodward streamflowgaging station. The period of detailed water-level records for 

OW-4 was from June 26, 2012, through December 8, 2013. 

The altitude of the land surface at OW-4 is 1,874.87 ft as 

measured with the Global Positioning System (GPS). Land use 

at the Woodward site in 2006 was classified as grassland (Fry 

and others, 2011), and the site is located on the valley bottom 

with little slope. During the period of data collection, the water 

table was between 6 and 7 ft below land surface and 104 of the 

527 days had measurable precipitation totaling 17.4 in. 

The Sy of the aquifer at the Woodward site had not been 

measured but was estimated on the basis of the general aquifer 

characteristics. Three wells with borehole logs used in the 

estimation of Kh in the “Hydrogeological Framework” section 

are located within 1 mi of observation well OW-4. All three 

borehole logs listed only sand (assumed to refer to medium 

sand) and fine sand in the upper 20 ft of the aquifer. The Sy of 

fine to medium sand ranges from 0.15 to 0.20 (Fetter, 1994). 

The mean of the two Sy values (0.18) was used for the BeaverNorth Canadian alluvial aquifer at the Woodward site. 

A water-level time series graph for well OW-4 (fig. 23) 

shows a decline of approximately 1.39 ft from June through 

September 2012, most likely due to plant uptake and little 

precipitation. There were 49 precipitation events, many lasting 

more than 1 day, during the period of data collection, and 

all were used to calculate recharge; the five largest peaks are 

described.

The first water-level peak associated with precipitation 

was a 0.04-ft (0.5 in.) rise on October 16, 2012, most likely 

related to 0.48 in. of precipitation on September 27 (fig. 23). 

Assuming an Sy of 0.18, the first precipitation event resulted 

in 0.1 in. of recharge. The water level then rose gradually 

0.29 ft (3.5 in.) from the end of October through most of 

February 2013. As shown on figure 23, from October 13 

through December 30 the water level rose 0.12 ft (1.5 in.) 

with only 0.22 in. of precipitation. During this period, there 

may have been more water moving into the area from another 

source because the water-level rise was approximately linear 

and indicates recharge of 0.26 in., which was more than the 

precipitation during that time. It was expected that plant 

uptake was minimal during October through December, which 

likely contributed to the water-level rise.

A sustained precipitation event from February 20 to 

March 9, 2013, with a total of 4.47 in. of precipitation, caused 

the water level to rise 1.39 ft (16.7 in.) above the projected 

water-level trend on March 4, 2013 (fig. 23); total estimated 

recharge was 3.0 in. The water level remained high because of 

several minor precipitation events until June 2013 when the 

water level declined rapidly. On June 11, 2013, the declining 

water-level trend was interrupted by a peak that rose 0.10 

ft (1.2 in.) above the declining trend, related to 0.92 in. of 

precipitation on June 4; recharge was 0.2 in (fig. 23). 

The water level continued to decline until a small peak 

of 0.08 ft (1.0 in.) related to 0.53 in. of precipitation on July 

17, 2013, (0.2 in. of recharge) and a 0.53 ft (6.3 in.) peak on 

August 8, 2013, for 1.1 in. of recharge. The August 8 peak was 

interpreted to be attributed to several precipitation events with 

a total of 2.36 in. that ended on July 19, 2013. Water levels 

continued to decline through October and then began to rise 

similar to November of 2012. 

The total precipitation recorded was 17.44 in., and 14.18 

in. occurred during the 2013 water year—October 2012–

September 2013 (fig. 23). With the WTF method using all 

rainfall events, approximately 6.3 in. of recharge (44 percent 

of precipitation) was calculated. For the SWB model, during 

the period 1980–2011 the mean annual precipitation at the 

location of OW-4 was 26.2 in., and the mean annual recharge 

was 2.4 in., which was 9.2 percent of precipitation and much 

lower than the percentage calculated by the WTF method. 

The difference between these estimates may be related to 

discretization of soil and land-use parameters for the SWB 

model. Recharge in SWB cells adjacent to the cell containing 

OW-4 ranged from 0.12 to 5.2 in. of recharge per year, which 

was 1–20 percent of precipitation. 

Seiling Site

Observation well OW-5 (fig. 1) at the Seiling site was 

approximately 1 mi from the Seiling streamflow-gaging 

station. The period of detailed water-level records for OW-5 

was from June 22, 2012, through December 3, 2013. The 

altitude of the land surface at OW-5 was measured with the 

GPS at 1,696.1 ft, and the altitude of the streamflow-gaging 

station at Seiling is 1,675.5 ft (U.S. Geological Survey, 

2013d). The groundwater head at the observation well was 
Hydrogeological Framework 37

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

Precipitation, in inches

0

5

10

15

20

25

30

35

40

Cumulative precipitation, in inches

2012 2013

June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Date

1,864

1,865

1,866

1,867

1,868

1,869

Water-level altitude, in feet 

above North American Vertical Datum of 1988

EXPLANATION

Cumulative precipitation

Precipitation

Water-level altitude at well OW–4—Location of

 observation well shown on figure 1

Projected trend

Water-level peak

Figure 23. Water-level fluctuation at observation well OW-4 and adjusted stream stage and precipitation at the North Canadian River 

at Woodward, Oklahoma (07237500), streamflow-gaging station.

approximately 9 ft higher than the stream stage, suggesting 

that the stream reach was generally gaining, as determined in 

both seepage runs reported in the “Stream Base Flow” section 

of this report (figs. 16 and 18). Land use at the Seiling site 

in 2006 was classified as a mix of grassland and cultivated 

cropland (Fry and others, 2011).

The Sy has not been measured and no borehole lithologic 

log was available for OW-5 or other wells near the Seiling 

site, so the published Sy for the range of textures found in the 

Beaver-North Canadian River alluvial aquifer (silty sand to 

fine gravel) was used to estimate Sy at the Seiling site. The 

Sy of silty sand is approximately 0.12, and a sand and gravel 

mixture has an Sy of approximately 0.22 (Fetter, 1994). A 

mean value of the two textures (0.17) was used for the aquifer 

at the Seiling site.

The depth to water in OW-5 fluctuated between 

approximately 6 and 8 ft below land surface during the period 

of measurement (1,687.8–1,689.5 ft altitude) and was sensitive 

to most precipitation events (fig. 24). All precipitation events 

were used in the WTF analysis, and several of the most 

substantial precipitation events are described.

As at the Woodward site, the water level dropped from 

June through September 2012, most likely related to plant 

uptake and minimal precipitation (fig. 24). The water level then 

reached a minimum in November and rose gradually with very 

little precipitation into February 2013. Precipitation of 4.21 

in. that ended on February 26 caused a 0.86 ft (10.3 in.) rise in 

water level that peaked on March 21 (fig. 24) for approximately 

1.8 in. of recharge. Seven more peaks were included in the 

analysis during a wet period that lasted from March through 

July of 2013, after which the water level dropped rapidly. 

Precipitation of 1.35 in. on July 15 caused a 0.21-ft (2.5 

in.) water-level peak on August 3 above the declining trend 

(fig. 24), for approximately 0.4 in. of recharge. The water level 

declined until two substantial precipitation events on July 26 

and 29, 2013, combined for 5.69 in. and caused the water level 

to peak 0.58 ft (6.9 in.) above the declining trend on August 15 

for approximately 1.2 in. of recharge. 
38 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

1686

1686.25

1686.5

1686.75

1687

1687.25

1687.5

1687.75

1688

1688.25

1688.5

1688.75

1689

1689.25

1689.5

1689.75

Water-level altitude, in feet 

above North American Vertical Datum of 1988

2012 2013

June July Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept. Oct. Nov. Dec.

Date

0

5

10

15

20

25

30

35

40

45

Cumulative precipitation, in inches

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

Precipitation, in inches

EXPLANATION

Cumulative precipitation

Precipitation

Water-level altitude at well OW–5—Location of

 observation well shown on figure 1

Projected trend

Water-level peak

Figure 24. Water-level fluctuation at observation well OW-5 and stream stage and precipitation at the North Canadian River near 

Seiling, Oklahoma (07238000), streamflow-gaging station.

Total recorded precipitation was 30.45 in., and 26.84 in. 

was during the 2013 water year at the Seiling site (fig. 24). 

The WTF method estimated a total of 6.9 in. of recharge 

related to this precipitation, which was 25.9 percent of 

precipitation. The SWB model calculated a mean annual 

precipitation at OW-5 of 28.75 in. per year and recharge of 

6.6 in. per year. The SWB model calculated that 23.0 percent 

of precipitation became recharge, which was very similar to 

the percentage from the WTF method.

Water Use

The OWRB-permitted water use described in the “Water 

Use and Management” section of this report was simplified 

for the conceptual flow model to the largest water-use 

categories and surface-water diversions from the Beaver and 

North Canadian Rivers. Groundwater use in the numerical 

groundwater-flow model was limited to irrigation and public 

water-supply wells pumping from the Beaver-North Canadian 

River alluvial aquifer. Irrigation and public water supply made 

up almost 90 percent of the long-term water use from both 

reaches (fig. 4).

There were 58 temporary and permanent surface-water 

diversions used in the model, with a total of approximately 

1,240 acre-ft/yr; 70 acre-ft/yr from Reach I and 1,170 acre-ft/

yr from Reach II. Because surface-water diversions were 

not from the Beaver-North Canadian River alluvial aquifer, 

these flow rates are not included in the conceptual flow model 

budget.

The mean annual volume of water pumped for irrigation 

and public water supply during the study period of 1980–2011 

was 14,500 acre-ft/yr in Reach I and 10,100 acre-ft/yr in 

Reach II, for a total of 24,600 acre-ft/yr. These volumes are 

greater than volumes in table 2 because the conceptual flow 

model includes 1980. 

Evapotranspiration and Springs

The only published report that addressed ET on the 

Beaver-North Canadian River alluvial aquifer was Mogg and 

others (1960), which included estimated plant ET for phreatic 

plants present in Canadian County, Okla., at the southeastern 

end of Reach II. Mogg and others (1960) estimated that 

cottonwoods and willows consumed on average 64.5 in. of 
Hydrogeological Framework 39

water per year and that the part of the Beaver-North Canadian 

River alluvial aquifer in Canadian County was 16.25 mi2. 

The mean annual ET for the Beaver-North Canadian River 

alluvial aquifer in Canadian County was approximately 

56,000 acre-ft/yr. As shown in figure 5, the mean annual 

precipitation in the eastern part of the Beaver-North Canadian 

River alluvial aquifer was approximately 35 in. Thus, adjusted 

for precipitation, the mean annual ET rate from groundwater 

where cottonwood and willows are present in Canadian 

County was approximately 30 in. per year. In the 1992 landuse classification, there were approximately 17,000 acres of 

deciduous forest, or 2 percent of the area of the Beaver-North 

Canadian River alluvial aquifer.

The SWB model calculated ET from plant consumptive 

use in the soil-water system but did not provide an estimate 

for the uptake from groundwater. Because estimation of 

groundwater ET flow was beyond the scope of this study, 

the ET flow for the conceptual flow model was not estimated 

directly for the aquifer water budget. Instead, ET was assumed 

to be equal to the balance of estimated groundwater recharge 

that was not discharged to streams or pumped by wells in 

Reach I; ET was not available for Reach II because base flow 

to streams was not calculated. The ET process was simulated 

in the numerical flow model, and an estimate for the flow 

is provided in the “Numerical Groundwater-Flow Model” 

section of this report.

There are numerous springs along the western boundary 

of the Beaver-North Canadian River alluvial aquifer where 

it is eroded, and the groundwater divide is inside the aquifer 

boundary (fig. 13). The flow from these areas has not been 

measured or estimated, and such analysis was beyond the 

scope of this study. In comparison to other budget categories, 

the water discharged from the Beaver-North Canadian River 

alluvial aquifer to springs appeared to be small because there 

were no apparent spring-fed perennial streams emanating 

directly from the boundary of the Beaver-North Canadian 

River alluvial aquifer, and the main evidence of springs was 

increased vegetation in draws observed in summer aerial 

orthophotographs (U.S. Department of Agriculture, 2013). No 

field observations or measurements of spring flow were made.

Continuously flowing springs are present at Boiling 

Springs and Roman Nose State Parks (fig. 11). The springs 

at Boiling Springs State Park are located where the terrace 

deposit thins and is missing toward the North Canadian River, 

exposing the Doe Creek Lentil of the Marlow Formation, 

which discharges groundwater through dissolution channels 

in the sandy limestone (Suneson, 1998). Groundwater in the 

Doe Creek Lentil originates in the terrace alluvium to the 

north and percolates into the limestone. Boiling Springs flow 

was estimated to be about 0.1 ft3/s in 1998, although flow may 

have decreased during the years preceeding 1998 because of 

local irrigation groundwater use (Suneson, 1998). Discharge 

from the springs is collected in a small reservoir used for 

recreation, which releases streamflow to a small drainage on 

the alluvium in the Beaver and North Canadian River flood 

plains. Most if not all of this water percolates into the alluvium 

before reaching the river.

Streamflow from springs at Roman Nose State Park 

emanates from dissolution features in salt and gypsum of the 

Blaine Formation beneath the northern part of Reach II, which 

is separated from the Beaver-North Canadian River alluvial 

aquifer in that area by 100 ft of the overlying Dog Creek Shale 

(Fay, 1959). There are three springs in the State park that have 

a combined discharge of 1.5–1.8 ft3/s (Fay, 1959). It is not 

known how thick the Dog Creek Shale is below the BeaverNorth Canadian River alluvial aquifer in all areas, but it is 

likely that the discharge from springs in Roman Nose State 

Park originates in the aquifer where the Dog Creek Shale is 

thin or absent, eroded by the North Canadian River. Discharge 

from the springs at Boiling Springs and Roman Nose State 

Parks was estimated to be no more than 1,500 acre-ft/yr, and 

some of the discharge at Boiling Springs returns to the aquifer.

Flow to springs in the Beaver-North Canadian River 

alluvial aquifer was not estimated as part of the conceptual 

flow model but was included with ET as the balance of 

recharge not discharged to streams and lakes or pumped by 

wells in Reach I. The amount of ET in Reach II as a balance 

of flow was not available because the base flow to streams was 

not calculated.

Conceptual Flow Model Water Budget

Estimates of the total flow into and out of the BeaverNorth Canadian River alluvial aquifer by reach and category 

are listed in table 9. This water budget is approximate and 

generalized, and a more detailed budget with annual flow 

is calculated by the numerical groundwater-flow model in 

the “Numerical Groundwater-Flow Model” section of this 

report. The only inflow to the Beaver-North Canadian River 

alluvial aquifer was determined to be recharge, and the two 

largest discharges from the aquifer were determined to be 

base flow to streams and lakes and ET to plants. In many 

aquifers, recharge is assumed to be equal to stream base 

flow, but in this case recharge estimated by using the SWB 

model was approximately 136,400 acre-ft/yr in Reach I, and 

flow to streams and lakes was estimated to be only 69,000 

acre-ft/yr; only 14,000 acre-ft/yr is estimated to be discharged 

to pumping wells (fig. 24; table 9). It was assumed that in 

Reach I inflow was equal to outflow, and ET and discharge 

to springs were responsible for the balance of groundwater 

discharge, which was approximately 53,400 acre-ft/yr 

(table 9). It is also assumed that the majority of water is lost to 

ET and a very small amount of water is lost to springs. 

In Reach II, the SWB model recharge was estimated 

at 82,400 acre-ft/yr, and discharge to pumping wells was 

12,000 acre-ft/yr (table 9). Discharge to stream base flow and 

the balance that may represent ET and spring discharge were 

not calculated.
40 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Numerical Groundwater-Flow Model

The primary objective of the numerical groundwaterflow model was to provide a model of the flow system to run 

transient simulations for water management and forecast the 

effects of water use and drought on available water. The model 

objective required a separate transient numerical model for 

Reach I and Reach II, hydrological boundaries, and flows to 

be constructed, calibrated, and run with various predictive 

scenarios. Separate models were constructed because the two 

reaches require independent calculations of EPS and separate 

water budgets.

Finite-difference numerical groundwater-flow models 

were constructed by using MODFLOW-2005 (Harbaugh, 

2005) for each of the two reaches of the Beaver-North 

Canadian River alluvial aquifer. Several modular packages 

were used to simulate flow and boundary conditions with the 

Newton formulation solver for MODFLOW-2005 (Niswonger 

and others, 2011). Steady-state and transient models were 

constructed for each reach, and the models used the same grid 

cell dimensions as those used for the SWB recharge analysis.

Assumptions

The use of the MODFLOW finite-difference flow model 

to simulate groundwater flow requires several assumptions 

about the system being modeled. Assumptions pertinent to 

this study include that the groundwater in the Beaver-North 

Canadian River alluvial aquifer flows according to Darcian 

flow principles, is incompressible, and can be simulated by 

using 1,640-ft by 1,640-ft cells and two layers of variable 

thickness. Many parameters such as Kh and Sy are known 

to change on a spatial scale smaller than 1,640 ft. The 

average value of measured or interpolated parameters in 

cells was assumed to adequately model the average flow 

conditions in the Beaver-North Canadian River alluvial 

aquifer. Also, though the parameters change on a local scale, 

they are not sampled on the scale of their spatial variance. 

The hydrogeologic framework is assumed to be a suitable 

basis to capture the textures of the Beaver-North Canadian 

River alluvial aquifer and represent the distribution of Kh of 

the aquifer for the groundwater-flow system. Model layers 

represent hydrogeological units that have spatially consistent 

hydraulic properties. It is assumed that the grid used and the 

aquifer samples were adequate to simulate varying hydraulic 

parameters and that the groundwater-flow system was at 

an approximate equilibrium during the initial model period 

of 1980. Because hydrologic data were not available for a 

period before groundwater resources were developed, a period 

when recharge and reported total groundwater pumping 

were similar was identified so that the flow system was not 

in a state of great change in flow. The year 1980 had similar 

stresses in comparison with 1979 and 1981 and is assumed to 

be sufficiently stable to avoid having to calibrate a model to a 

system that is undergoing change on a time scale smaller than 

the model time steps.

Model Extents and Discretization

The numerical groundwater-flow models for Reach I and 

Reach II took advantage of the most current packages and 

processes available for MODFLOW at the time this study 

was conducted to simulate the major hydrological processes 

operating on the Beaver-North Canadian River alluvial 

aquifer. Discretization of the aquifer was performed to best 

simulate these processes and capture the spatial variability 

in model parameters and flows. Starting values for hydraulic 

properties Sy and Kh were taken from the estimates described 

in the “Hydrogeological Framework” section of this report and 

were adjusted during calibration.

Two separate models were constructed for the two 

reaches of the Beaver-North Canadian River alluvial aquifer. 

The boundary between Reach I and Reach II as defined by 

the OWRB is at the Canton Dam (fig. 1). To avoid having 

the model active area boundary near several pumping wells 

(fig. 2), which could cause the boundary to affect flow to 

wells, the transition from Reach I to Reach II was moved 

just south of Canton Lake, near the town of Canton, along 

a line approximately perpendicular to the general trend of 

the Beaver-North Canadian River alluvial aquifer (fig. 25). 

Groundwater and surface water were allowed to leave the 

Reach I model and enter the Reach II model through boundary 

cells as described in the “Boundary Conditions” section of this 

report. The two models were not linked and were calibrated 

independently.

Because the Beaver-North Canadian River alluvial 

aquifer is thin and unconfined, the Newton formulation solver 

for MODFLOW (MOFLOW-NWT v. 1.0.8; Niswonger 

and others, 2011) was used. This solver is built on the 

MODFLOW-2005 version (Harbaugh, 2005) and allows cells 

to be rewetted if they become dry, which is likely to occur in 

a transient simulation of groundwater in a thin alluvial aquifer 

with varying climatic conditions.
Numerical Groundwater-Flow Model 41

Reach I model domain

Reach II model domain

BNCA

Reach I

BNCA

Reach II

Canton

Woodward

Calumet

El Reno

Watonga

Yukon

Seiling

HARPER COUNTY

WOODS COUNTY

GRANT COUNTY

ALFALFA COUNTY

WOODWARD 

COUNTY GARFIELD COUNTY

ELLIS COUNTY

MAJOR COUNTY

BLAINE

COUNTY

KINGFISHER

COUNTY

DEWEY COUNTY

CUSTER COUNTY

ROGER MILLS COUNTY

CANADIAN COUNTY

GRADY COUNTY

BECKHAM COUNTY

WASHITA COUNTY

OKLAHOMA

COUNTY

BEAVER COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY CADDO COUNTY

LOGAN COUNTY

Beaver River

Fort Supply

Lake

Wolf Creek

North Canadian River

Canton

Lake

Lake Hefner Canal

Lake Overholser

Canadian River

Cimarron River 100° 99°30' 99° 98°30' 98°

37°

36°30'

36°

35°30'

0 10 20 30 40 MILES

0 10 20 30 40 KILOMETERS

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

EXPLANATION

Reach I active model cell

Reach II active model cell

Reach model grid extent

 Reach I model grid extent boundary

 Reach II model grid extent boundary

Beaver-North Canadian River 

 alluvial aquifer (BNCA) boundary

Boundary-condition model cell—Package used for 

 boundary-condition simulation

 Stream—Streamflow-routing package (Niswonger 

 and Prudic, 2005)

 Lake—Lake package (Merritt and Konikow, 2000)

 General-head boundary—General-Head Boundary

 package (Harbaugh and others, 2000)

 Well—Well package (Harbaugh and others, 2000)

 Spring—Drain package (Harbaugh and others, 2000)

Figure 25. Reach I and Reach II numerical groundwater-flow model layouts, active areas, and boundary condition cells excluding 

wells, Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.
42 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Discretization is the process of converting continuous 

variables in space or time to discrete partitions, which results 

in some measure of generalization and uncertainty. The aquifer 

top and bottom and hydraulic properties are continuous 

variables that must be represented in a finite-difference 

grid and layer structure for the MODFLOW groundwaterflow model software. Thus, the size of grid cells and their 

thicknesses must be chosen so that the spatial variations 

in parameters, such as aquifer thickness, Kh, and Sy and 

interactions between boundary conditions such as streams and 

wells, are adequately captured without having more than one 

boundary condition in a single cell. Cell dimensions also affect 

the computational requirements to solve the groundwater-flow 

equation between cells for each stress period. Thus, cells were 

chosen to be small enough to characterize the flow system and 

variability in aquifer properties but not so small that solving 

the model with available computers would be unmanageable. 

The cell size adequate to simulate the Beaver-North Canadian 

River alluvial aquifer properties and flow system in both 

models was determined to be 1,640 ft on all sides. Because 

the Beaver-North Canadian River alluvial aquifer consists 

of a single hydrogeological unit, each cell used one layer for 

the Beaver-North Canadian River alluvial aquifer. Where 

the aquifer was missing, cells were made inactive in layer 1 

and were considered no-flow boundaries within the active 

grid. Starting Kh and Sy parameters were estimated in the 

“Hydrogeological Framework” section and were assigned to 

the cells. In some areas, the cell size was too large to discretize 

the thin aquifer on steep slopes, and the aquifer thickness was 

increased slightly, which caused some uncertainty. 

Underlying bedrock was included as an underlying layer 

(layer 2) to simulate the exchange of water between bedrock 

and the Beaver-North Canadian River alluvial aquifer. Layer 2 

was not a single hydrogeological unit; each cell was assigned 

the general hydraulic properties of the bedrock lithology. All 

calibration, budget, and flow analyses were performed on 

layer 1.

For the steady-state models, one stress period and 

time step that used annual mean flow values was simulated 

for 1980. The MODFLOW stress period was 366 days 

long to calculate model budget flows. Because the BeaverNorth Canadian River alluvial aquifer is directly connected 

to surface water and precipitation, plant demands, and 

groundwater pumping—all of which have strong seasonal 

fluctuations—stress periods in the transient models were set 

at 1 month each. Four time steps were solved in each stress 

period to capture changes in head and stress-period flows 

caused by monthly changes in stress. Both model simulations 

started with a steady-state stress period for 1980, which was 

the last year of analyses reported in Davis and Christenson 

(1981) and Christenson (1983). From 1981 through 2011, the 

models used transient monthly stress periods.

The initial potentiometric surface is the groundwater head 

in the aquifer when the simulation began. The initial head was 

modified from the maps produced by Davis and Christenson 

(1981) and Christenson (1983) and all available water-level 

measurements from 1980. Head observations used in the 

model calibration were taken from wells screened only in the 

Beaver-North Canadian River alluvial aquifer and measured 

during the model period, 1980–2011 (U.S. Geological Survey, 

2013c). No head observations from the bedrock units were 

used, and no calibration of bedrock properties was performed. 

Head observations were not used if the well was in the same 

cell as a boundary control such as a stream or river or if a head 

observation was within two cells of a groundwater-pumping 

well.

Boundary Conditions

Boundaries defined in the “Conceptual Flow Model” 

section of this report were incorporated into the model by 

assigning boundary conditions to the appropriate cells (such 

as wells, streams, and lakes) or by assigning flows to areas 

(such as recharge or ET). Cells with boundary conditions 

are shown on figure 25. Mean daily recharge from the SWB 

model was included in the models by using the Recharge 

package (Harbaugh and others, 2000). A recharge flow rate for 

each stress period was applied to layer 1. Where the BeaverNorth Canadian River alluvial aquifer is missing and bedrock 

is exposed, no recharge was assumed to occur. Output arrays 

from the SWB model were used as model input for the steadystate and transient models. The steady-state models used an 

array of the mean daily recharge for 1980, and the mean daily 

recharge for each month in the transient models was used for 

each transient stress period.

The ET from groundwater was simulated by using the 

Evapotranspiration package (Harbaugh and others, 2000). This 

package sets the extinction depth or the vegetation root-zone 

depth at each cell. If the groundwater head rises above the 

extinction depth, the Evapotranspiration package calculates 

the flow because of plant consumptive use and limits ET to the 

supplied maximum ET flow. The extinction depth was set at 

the root-zone depth used by the SWB model. The maximum 

ET flow rate was equivalent to the SWB model potential ET 

calculated for each stress period. The SWB model assumed 

that the vegetation could not access groundwater and limited 

actual ET by the available soil moisture, but if the water 

table was as shallow as the root zone, the actual ET could 

equal the potential ET. Because the SWB model already 

reduced recharge by the actual ET, the maximum ET in the 

Evapotranspiration package was set equal to the difference 

between the SWB model potential and actual ET. Both the 

maximum ET and extinction depth were parameters that were 

adjusted during model calibration.

Streams were simulated in the models by using the 

Streamflow-Routing package version 2 (SFR2) (Niswonger 

and Prudic, 2005), and lakes were simulated by using the 

Lake package (Merritt and Konikow, 2000). The SFR2 and 

Lake package work together, routing water between lakes 

and streams and simulating flow between surface water and 

groundwater. Both packages track the surface-water stage 

by stress period and calculate interactions with the aquifer 
Numerical Groundwater-Flow Model 43

on the basis of the groundwater head in the aquifer relative 

to the stream or lake stage. Flow between surface water and 

groundwater is controlled by the hydraulic conductivities 

of the aquifer and stream or lakebed. The SFR2 allows 

streamflow to be input to reaches to simulate inflow from 

outside the model or removed from reaches to simulate 

surface-water diversions. Because most of the channels of the 

Beaver and North Canadian Rivers are sandy, initial streambed 

hydraulic conductivity for all stream segments was set at 

13 ft/d, the approximate hydraulic conductivity of fine sand, 

and lakebed hydraulic conductivity was set equal to that of 

clay, 0.7 ft/d (Fetter, 1994). Streambed and lakebed hydraulic 

conductivity were adjusted during model calibration.

Streamflow measurements from USGS streamflowgaging stations (U.S. Geological Survey, 2013d) and releases 

from lakes in the study area (U.S. Army Corps of Engineers, 

2013) were used to assign the flow into and out of lakes and 

streams. Streamflow from the Beaver River at Beaver, Okla. 

(07234000), streamflow-gaging station was routed into the 

upstream segment of the Beaver River in Reach I. Streamflow 

entering the model in Wolf Creek was taken from the Wolf 

Creek near Gage, Okla. (07235600), streamflow-gaging station 

(fig. 1) and the Wolf Creek at Lipscomb, Texas (07235000), 

streamflow-gaging station. The Lipscomb streamflow-gaging 

station was located approximately 30 mi upstream to the west 

from the Gage streamflow-gaging station and is shown on 

the figure 1 inset map; streamflow data from this station were 

used to fill in gaps in the streamflow record from Wolf Creek 

near Gage. Lake releases from Fort Supply Lake and Canton 

Lake (U.S. Army Corps of Engineers, 2013) were routed into 

the nearest downstream SFR2 stream segment. Streamflow 

released from Canton Lake was routed into the short stream 

segment below the lake in the Reach I model and into the first 

stream segment in the Reach II model (fig. 25).

Long-term and temporary Beaver and North Canadian 

Rivers diversion volumes (Oklahoma Water Resources Board, 

2014) were simulated as being from the SFR2 stream segment 

nearest to the location of the permitted diversion during the 

stress periods that the permit was active. Because the monthly 

diversion rates for temporary diversions were not recorded, 

the total permitted diversion volume was set at a constant rate 

over the 3-month period that each permit covered.

Lateral groundwater flow into or out of the models from 

the Ogallala Formation or upstream or downstream alluvium 

was simulated by using the General-Head Boundary (GHB) 

package (Harbaugh and others, 2000) (fig. 25). A GHB 

occupies a single model cell with specified head for each stress 

period. Groundwater can enter or leave the model through 

GHBs regulated by the relative head between the aquifer and 

GHB and the specified boundary conductance.

 The groundwater head in each GHB was set at the 

estimated head from the initial potentiometric surface in the 

Beaver-North Canadian River alluvial aquifer at the start of 

the simulation, and the hydraulic properties were set at the 

estimated hydraulic properties of the Ogallala Formation 

(3.5 ft/d; table 7). Flow into the Beaver-North Canadian River 

alluvial aquifer along the upstream extent of Reach I, across 

the boundary between the two reaches, and out of the model 

at the downstream extent of Reach II were all simulated by 

using GHB cells with the estimated starting head and Kh of 

the aquifer. Conductivity and groundwater head in GHB cells 

were adjusted during model calibration.

Groundwater pumped from the Beaver-North Canadian 

River alluvial aquifer was simulated by using the Well 

package (Harbaugh and others, 2000). Every model cell with a 

well was assigned a flow for each stress period, and if multiple 

wells were located in one cell, pumping was set at the sum 

of discharge for all wells. The annual withdrawal rates from 

groundwater-pumping wells used in the “Conceptual Flow 

Model” section were input into the steady-state and transient 

periods by using the model cell in which each permitted well 

fell on the basis of the location provided by the OWRB. If 

more than one well shared the permitted pumping for a single 

permit, the reported flow for that permit was divided equally 

among all wells. Withdrawal was assigned to the stress periods 

in which the permit was active. 

The steady-state models used the 1980 pumping rate for 

each well, but the transient models used monthly stress periods 

so the withdrawal rates had to be distributed across months. 

The Oklahoma Water Resources Board (2012) includes 

estimates for the monthly percentage of the annual water 

discharge that different categories of wells pump by county. 

This percentage was used for each county in the study area 

to approximate the monthly fraction of annual pumping rates 

for transient stress periods. There were 301 irrigation and 57 

public water-supply well boundary conditions that were tied to 

groundwater permits active during the period of study (fig. 2). 

Well boundary conditions consolidated some wells that were 

in the same model cell. 

Springs that discharge water along the eastern margin 

of the Beaver-North Canadian River alluvial aquifer were 

simulated with the Drain package (Harbaugh and others, 

2000). The Drain package functions independently of other 

boundaries and only allows groundwater to leave the model. 

Because no springs have been mapped by previous studies 

and no flow has been measured along the eastern margin, 

drains were placed where a possible spring was located based 

on where thick vegetation visible on aerial orthophotographs 

indicated that a seep or small spring may exist. Discharge at 

drains was expected to be small relative to other boundaries. 

The altitude of each drain was set at the approximate land 

surface altitude derived from DEMs (U.S. Geological Survey, 

2013a). Groundwater flow through drains is controlled 

by aquifer head relative to the altitude of a spring and the 

conductance of the drain. The initial conductance was set 

equal to the aquifer hydraulic properties at each drain location, 

and the drain altitude and conductance were adjusted to 

improve model calibration and limit spring flow to 0.1 ft3/s 

or less. Not all drains had flow because the groundwater head 

was not always higher than the drain altitude.
44 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Model Calibration Methods

The steady-state and transient models for each reach were 

calibrated to groundwater-head observations. Because the 

primary model objective was to estimate EPS, the saturated 

thickness and changes in head in response to pumping were 

the main characteristics of interest; stream base-flow readings 

were not included as model observations.

To determine the accuracy and confidence in the 

model simulations, the steady-state and transient head fields 

were observed at various points in time and compared to 

observed head values retrieved from the National Water 

Information System (U.S. Geological Survey, 2013a) by 

using the Head-Observation package (Hill and others, 2000). 

Head residuals were calculated by the Head-Observation 

package by subtracting the simulated head from the observed 

head. Groundwater-head measurements were assumed 

to have 5–10 percent error combined in the land-surface 

altitude measurement and the measurement of the depth to 

groundwater. 

Model parameters including recharge, Kh, and Sy 

for layer 1, maximum ET, and altitude and conductance of 

selected streams, lakes, GHBs, and drains were adjusted 

within reasonable limits to reduce residuals and increase 

the confidence of the models. Because there were no 

observations or boundary controls in layer 2 (bedrock) and 

head observations in layer 1 were not sensitive to parameter 

changes in layer 2, parameters in layer 2 were not adjusted 

during model calibration. 

Recharge was adjusted with multiplier arrays, and other 

parameters were adjusted directly. For both models, one 

recharge multiplier array was used for the steady-state stress 

period, and another was used for all transient stress periods. 

Parameters were adjusted until the residual improvement was 

only marginal and it was apparent that the residuals could 

not be improved further without using unrealistic parameter 

values. 

For both reaches, a separate steady-state model was 

calibrated for conditions in 1980 by changing Kh, ET, 

and boundary-control parameters and scaling recharge on 

a cell-by-cell basis within reasonable parameter limits to 

minimize head residuals. The results of this calibration were 

used in the transient models for the starting potentiometric 

surface and Kh. The transient models were calibrated by 

adjusting the recharge by scaling the SWB recharge arrays 

with one multiplier for all stress periods. The Kh and Sy 

were adjusted on a cell-by-cell basis in the transient model in 

areas where there were head targets from the transient period 

but no steady-state period targets. The ET extinction depth 

and maximum ET rate were adjusted on a cell-by-cell basis 

in limited areas where groundwater was shallow. The GHB 

conductance and groundwater head were adjusted to improve 

calibration in local areas directly affected by GHBs.

Reach I Calibration Results

The Reach I model calibration used 47 observation wells, 

with a total of 515 groundwater-head observations during the 

model period; 28 observations were used during the steadystate period, and 487 were used during the transient period. 

Groundwater-head observations were from both the terrace 

and alluvial deposits. Reach I model calibration resulted in 

a good correlation between measured and simulated heads 

for both the steady-state and transient stress periods, with a 

coefficient of determination (R2) of 0.9996 (fig. 26). Of the 

residuals from the steady-state and transient stress periods, 

Simulated head equals 0.9971 times measured head plus 6.860

Coefficient of determination (R2) equals 0.9996

Simulated head, in feet above 

North American Vertical Datum of 1988 

1,600

1,700

1,800

1,900

2,000

2,100

2,200

1,600 1,700 1,800 1,900 2,000 2,100 2,200

Measured head, in feet above

North American Vertical Datum of 1988

Groundwater-head observation

EXPLANATION

Figure 26. Observed groundwater heads plotted with simulated 

heads combined for the steady-state and transient models for 

Reach I of the Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma.
Numerical Groundwater-Flow Model 45

83 percent were between -5 and 5 ft (fig. 27). Residual 

distribution skewed to the positive, indicating that the 

simulated heads were more commonly lower than observed 

values. The final simulated potentiometric surface and 

locations of observation wells symbolized by mean residuals 

for observation wells with multiple readings for each well 

during the transient and steady-state periods are shown in 

figure 28. 

Residual statistics show that the Reach I numerical 

groundwater-flow model provides a reasonable simulation of 

the aquifer head observations. Steady-state period residuals 

ranged from -5.61 to 3.46 ft with a mean of -0.64 ft and from 

-12.14 to 15.01 ft with a mean of 0.87 ft for the transient 

period (table 10). The mean for all residuals was 0.79 ft. The 

mean of the absolute value of residuals and the root-meansquare error (RMSE), which is the square root of the mean of Frequency

0

20

40

60

80

100

120

140

160

–13 –11 –9 –7 –5 –3 –1 1 3 5 7 9 11 13 15

Head residual, in feet

Figure 27. Head residual values combined for the steady-state 

and transient models for Reach I, Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma.

squared model residuals, provide a measure of error without 

negative and positive residuals canceling each other out. The 

mean of residual absolute values was 1.67 ft for the steady 

state period, 2.82 ft for the transient period, and 2.76 ft for all 

residuals. The RMSE was 2.31 ft for the steady-state period, 

3.93 ft for the transient period, and 3.86 for all observations. 

The RMSE as a percentage of the total head relief in the 

model, or the difference between highest head and lowest 

head in the model (731 ft from fig. 28), provides the error 

in the context of the model head variability. The RMSE as 

a percentage of head relief was 0.3 percent for the steadystate period and 0.5 percent for the transient period and all 

observations.

The final calibrated Reach I numerical groundwater-flow 

model provides estimates of the model groundwater heads, 

input parameters, and stream base flow in the groundwater 

system. Reach I Kh ranged from 6 to 279 ft/d, with a mean 

of 70 ft/d (table 11), and is shown in figure 15. The simulated 

head at the end of the transient model period—December of 

2011—was compared to the base of the aquifer to calculate 

the saturated thickness. Reach I mean saturated thickness 

was 36 ft, and the maximum aquifer thickness was 308 ft 

(table 11).

Table 12 lists the Reach I model mean annual flow budget 

for recharge, lateral groundwater flow, flow into and out of 

storage, ET, base flow to lakes and streams, groundwater 

pumping, and flow to springs; figure 29 shows the relative 

mean annual flows for recharge, combined flow for ET 

and springs, combined base flow to streams and lakes, and 

groundwater pumping. Calibrated Reach I recharge was 

slightly higher than the estimated SWB-model recharge for the 

conceptual flow model in table 9. Estimated base flow for the 

conceptual flow model in Reach I was much higher than in the 

numerical groundwater-flow model, possibly because of the 

large volume of ET calculated by the model (fig. 29; table 9). 

In table 12 the sum of the inflow categories does not match 

the sum of the outflow categories exactly because of round-off 

errors after converting flow from model units of cubic meters 

to acre-feet.
46 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Fort Supply

Lake

Canton

Lake

!

!

!

! ! ! !

! !

!

!

!!

!

!

!

!

!

!

!

! !

! ! !

! !

!

!

!

2,140

1,880

2,100

2,260

2,080

1,660

2,140

2,200

2,180

2,140

2,000

1,920

2,120

1,900

2,100

1,960

2,120

1,880

1,640

1,860

2,040

1,840

1,660

2,060

1,960

1,740

1,720

1,760

1,800

1,780

1,700

1,940

2,040 2,060

2,000

2,040

2,020

1,980

1,680

1,820

1,980

2,020

2,060

2,080

2,020

2,080

2,020

2,060 2,100

2,160

2,240

2,220

2,120

2,080

2,080

2,020

1,620

1,680

1,600

2,040

2,100

2,100

2,000

1,900

2,000

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

0 5 10 15 20 MILES

0 5 10 15 20 KILOMETERS

OKLAHOMA

BNCA Reach I area

Mean transient head

 residual, in feet

 –2.05 to –1.09

 –1.08 to –0.32

 –0.31 to 0.13

 0.14 to 0.67

 0.68 to 1.51

Lake cell

Aquifer missing

Beaver-North Canadian River

 alluvial aquifer (BNCA) 

 boundary 

Simulated potentiometric head

 contour—Shows simulated 

 altitude at which water level

 would have stood in tightly 

 cased wells. Contour interval

 20 feet. Datum is NAVD 88

Simulated potentiometric head, in

 feet above North American Vertical

 Datum of 1988 (NAVD 88)

 1,561 to 1,650

 1,651 to 1,742

 1,743 to 1,833

 1,834 to 1,928

 1,929 to 2,017

 2,018 to 2,094

 2,095 to 2,183

 2,184 to 2,292

EXPLANATION

1,700

ELLIS COUNTY DEWEY COUNTY

WOODWARD COUNTY

WOODS COUNTY

HARPER COUNTY

MAJOR COUNTY

BLAINE

COUNTY

TEXAS

OKLAHOMA

KANSAS

OKLAHOMA

100° 99°45' 99°30' 99°15' 99° 98°45'

37°

36°45'

36°30'

36°15'

36°

Figure 28. Simulated potentiometric surface at the end of the transient simulation and head targets in Reach I symbolized by mean 

residual for the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.
Numerical Groundwater-Flow Model 47

Table 10. Statistical comparison of measured and simulated groundwater heads, numerical groundwater-flow model for the BeaverNorth Canadian River alluvial aquifer, northwestern Oklahoma.

[Residual is calculated as the measured value minus the simulated value; thus, a negative residual for water levels indicates that simulated values are larger than 

measured values; all units except percentage of head relief are feet]

Model Reach I Reach II

Observation group Steady state Transient All Steady state Transient All

Observation count 28 487 515 75 134 209

Minimum residual -5.61 -12.14 -12.14 -3.79 -10.02 -10.02

Mean residual -0.64 0.87 0.79 -0.69 -0.23 -0.39

Maximum residual 3.46 15.01 15.01 9.83 10.57 10.57

Mean absolute residual 1.67 2.82 2.76 1.71 3.26 2.66

Root-mean-square error (RMSE) 2.31 3.93 3.86 2.40 4.15 3.58

RMSE percentage of head relief 0.3 0.5 0.5 0.6 1.0 0.8

Table 11. Statistical summary for calibrated hydraulic conductivity and saturated thickness for the Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma.

[Saturated thickness represents conditions during December 2011 at the end of the transient model period; mi2, square mile; Kh, horizontal hydraulic 

conductivity]

Reach Cell count Area 

(mi2)

Mean 

saturated 

thickness 

(feet)

Maximum 

thickness 

(feet)

Minimum Kh 

(feet per day)

Mean Kh 

(feet per day)

Maximum Kh 

(feet per day)

Reach I 8,894 858 36 308 6 70 279

Reach II 3,843 371 29 86 4 92 279

Aquifer total 12,737 1,229 34 308 4 77 279

Table 12. Numerical groundwater-flow model mean annual flow budget, Beaver-North Canadian River alluvial aquifer, northwestern 

Oklahoma.

[All units are acre-feet; ET, plant evapotranspiration; positive values are flow to aquifer; negative values are discharge]

Reach I Reach II Total

Inflow

Recharge 143,990 60,950 204,940

Flow from storage 114,580 48,610 163,190

Flow from streams 37,570 36,460 74,030

Lateral inflow 14,630 930 15,560

Flow from lakes 170 20 190

Total inflow 310,940 146,970 457,910

Outflow

Evapotranspiration 101,100 33,610 134,710

Storage 115,470 50,910 166,380

Streams 61,830 50,020 111,850

Reach I Reach II Total

Outflow—Continued

Groundwater pumping 12,490 8,620 21,110

Lateral outflow 10,800 880 11,680

Springs 8,270 2,920 11,190

Flow to lakes 990 10 1,000

Total outflow 310,950 146,970 457,920

Net flow

Streams -24,260 -13,560 -37,820

Lateral flow 3,830 50 3,880

Net change in storage 890 2,300 3,190

Lakes -820 10 -810
48 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Budget category

Recharge Evapotranspiration

and springs

Net base flow

to streams

and lakes

Groundwater

pumping

–150,000

–100,000

–250,000

–200,000

–50,000

0

50,000

100,000

150,000

200,000

250,000

Mean annual flow, in acre-feet

EXPLANATION

Reach I

Reach II

Figure 29. Numerical groundwater-flow model mean annual flow 

budget for the period 1980–2011, Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma. 

Reach II Calibration Results 

A total of 209 groundwater-head measurements were 

used in calibration of the Reach II model, 75 of which were 

from the steady-state period of 1980, and 134 of which 

were from 31 wells used during the transient stress periods 

(table 10). The groundwater head observed at each observation 

well was compared to the simulated heads in figure 30. The 

correlation between observed and simulated groundwater 

heads was nearly 1:1, with a R2 of 0.9993. The distribution of 

Reach II head residuals shows that the model error was evenly 

distributed between simulating head greater than observed 

and less than observed (fig. 31). For Reach II, 85 percent of 

residuals from the steady-state and transient stress periods 

were between -5 and 5 ft (fig. 31). Residuals ranged from 

-3.79 to 9.83 ft for the steady-state period, with a mean of 

-0.69 ft, and -10.02 to 10.57 ft, with a mean of -0.23 ft during 

the transient period (table 10). The mean of all residuals was 

-0.39 ft. The mean of residual absolute values was 1.71 ft 

for the steady state period, 3.26 ft for the transient period, 

and 2.66 ft for all residuals. The RMSE was 2.40 ft for the 

steady-state period, 4.15 ft for the transient, and 3.58 ft for 

all observations. The RMSE as a percentage of the total head 

relief in the model (437 ft from fig. 32) provides the error 

in the context of the model head change. The RMSE as a 

percentage of head relief was 0.6 percent for the steady-state 

period, 1.0 percent for the transient period, and 0.8 for all 

observations.

Simulated head equals 0.9934 times measured head plus 8.731

Coefficient of determination (R2) equals 0.9993

Simulated head, in feet above

North American Vertical Datum of 1988

1,150

1,250

1,350

1,450

1,550

1,650

Measured head, in feet above

North American Vertical Datum of 1988

1,150 1,250 1,350 1,450 1,550 1,650

EXPLANATION

Groundwater-head observation

Figure 30. Observed groundwater heads and simulated heads 

for Reach II of the Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma. Frequency

10

20

30

40

50

60

70

0

–13 –11 –9 –7 –5 –3 –1 1 3 5 7 9 11 13 15

Head residual, in feet

Figure 31. Distribution of head residuals combined for the 

steady-state and transient models for Reach II, Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma.
Numerical Groundwater-Flow Model 49

Base from U.S. Geological Survey digital data

Universal Transverse Mercator, zone 14

North American Datum of 1983

Aquifer boundary modified from Oklahoma Water Resources Board (2012)

0 5 10 15

0 5 10 15 20 KILOMETERS

20 MILES

OKLAHOMA

BNCA Reach II area

Mean transient head

 residual, in feet

 –5.9 to –3.9

 –3.8 to –1.0

 –0.9 to 1.0

 1.1 to 2.4

 2.5 to 4.1

Lake cell

Aquifer missing

Beaver-North Canadian River

 alluvial aquifer (BNCA) 

 boundary 

Simulated potentiometric head

 contour—Shows simulated 

 altitude at which water level

 would have stood in tightly 

 cased wells. Contour interval

 20 feet. Datum is NAVD 88

Simulated potentiometric head, in

 feet above North American Vertical

 Datum of 1988 (NAVD 88)

 1,190 to 1,257

 1,258 to 1,313

 1,314 to 1,373

 1,374 to 1,432

 1,433 to 1,481

 1,482 to 1,531

 1,532 to 1,577

 1,578 to 1,627

EXPLANATION

1,510

CANADIAN COUNTY

CADDO COUNTY

KINGFISHER COUNTY

BLAINE COUNTY

LOGAN COUNTY OKLAHOM

A COUNTY

1,250

1,310

1,330

1,370

1,330

1,350

1,310

1,290

1,270

1,270

1,290

1,310

1,350

1,370 1,390

1,410

1,330

1,350

1,370

1,290

1,290

1,370

1,250

1,230

1,210

1,230

1,270

1,410

1,430

1,450

1,470

1,490

1,490

1,510

1,510

1,530

1,550

1,570

1,570

1,590

1,610

1,610

1,530

1,390

36°

35°45'

35°30'

98°30' 98°15' 98° 97°45'

Figure 32. Simulated groundwater head and head targets symbolized by mean residual combined for the steady-state and transient 

models for Reach II of the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.
50 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

The final calibrated numerical groundwater-flow model 

for Reach II provided estimates of the heads, model input 

parameters, and stream base flow in the groundwater system. 

Reach II Kh ranged from 4 to 279 ft/d, with a mean of 92 

ft/d (table 11). The simulated head at the end of the transient 

model period—December of 2011—was compared to the 

base of the aquifer to calculate the saturated thickness. Reach 

II mean saturated thickness was 29 ft, and the maximum was 

86 ft. 

The Reach II model mean annual flow budget (fig. 29; 

table 12) shows the simulated flow for several categories to be 

much different than the flows estimated in the conceptual flow 

model (table 9). Recharge scaled during calibration was about 

74 percent of the total SWB-model annual recharge volume 

for Reach II. The SWB-model recharge was most likely 

overestimated, but the amount of plant ET calculated by the 

model may have been less than the volume that was actually 

discharged. Thus, the lower volume of recharge in the Reach II 

model may have compensated for ET that was not simulated. 

Model Sensitivity

The sensitivity of simulated heads in both models to 

changes in hydraulic parameters, maximum ET, and recharge 

was determined. Sensitivity was measured by varying the 

final calibrated arrays for recharge, Kh, Sy, and maximum 

ET equally across the model by 10 percent independently 

and calculating the resulting change in simulated heads at 

observation points. Changes in head at each observation point 

were then scaled by the number of observations to determine 

the mean model sensitivity. The model sensitivity helps 

to identify which parameters contribute most to the model 

solution and thus estimate the model confidence.

The Reach I model simulated head was most sensitive to 

changes in recharge and much less sensitive to changes in Kh, 

Sy, and maximum ET (fig. 33). Simulated head observations 

were nearly three times as sensitive to recharge as they were 

to Kh, which was nearly double that of Sy. The Reach II 

model simulated head was much less sensitive to recharge, 

and the recharge and Kh sensitivities were almost an order of 

magnitude higher than those of Sy and maximum ET.

Equal-Proportionate-Share Estimation

The EPS pumping rate of groundwater for alluvial 

aquifers is defined by the State of Oklahoma as the 

hypothetical constant rate of groundwater pumping per acre 

of land that results in half of the aquifer having saturated 

thickness of 5 ft or less after a period of 20 years (Oklahoma 

Statutes Title 82 Section 1020.5, 2011). For the Beaver-North 

Canadian River alluvial aquifer, the EPS estimation also 

included periods of 40 and 50 years. To determine the EPS 

pumping rate, the reach models were modified to include 

Parameter

Recharge Hydraulic

conductivity

Specific yield Maximum

evapotranspiration

0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

Mean head change, in feet 

EXPLANATION

Reach I

Reach II

Figure 33. Reach I and Reach II numerical groundwater-flow 

model groundwater-head sensitivity to changes in selected 

parameters, Beaver-North Canadian River alluvial aquifer, 

northwestern Oklahoma.

one hypothetical groundwater-pumping well in each active 

model cell. Each well pumped the same EPS rate, and this 

rate was held constant throughout the transient model period. 

At the end of the transient model run, the number of model 

cells with 5 ft or less of saturated thickness was counted, and 

the percentage of the basin was calculated in a geographic 

information system (Esri, Inc., 2015). This process was 

repeated with incremental increases in pumping for all wells 

until half of the cells had a saturated thickness of 5 ft or less. 

This discharge was determined to be the approximate EPS 

pumping rate. To provide a range of EPS pumping rates, the 

process was repeated with recharge, to which heads were most 

sensitive, and increased and decreased by 10 percent. 

All of the model EPS runs began with the simulated head 

and model inputs of 2011. To include climatic and water-use 

variations of the model period without causing perturbations 

to the system outside of normal fluctuations, the transient 

model was then reconfigured to step back through the 31-year 

transient model period. The 20-year EPS calculation stepped 

backward through model data for 1991–2011. For the 40- and 

50-year periods, the model inputs included the entire 31-year 

transient model period stepping backward (2011–1981), 

then stepping forward again for nine years (1981–89) for 

the 40-year period, and 19 years (1981–99) for the 50-year 

period. Model inputs for recharge, surface-water releases and 

diversions, and ET rates were the same as those used in each 

stress period of the calibrated models. 

The EPS pumping rates are approximate and affected 

by several factors. Because the EPS rate is determined by the 
Equal-Proportionate-Share Estimation 51

changes in saturated thickness of the Beaver-North Canadian 

River alluvial aquifer under pumping stresses, the irregular 

nature of the aquifer base, discretization of an irregular 

surface, and error in the model used introduce uncertainty. 

Seasonal fluctuations in recharge and ET introduce 

uncertainty, particularly in the longer runs of 40 and 50 years 

because the aquifer saturated thickness changes on a seasonal 

time scale. In some cases, the EPS pumping rate may not be 

distinguishable or is only separated by 0.1 (acre-ft/acre)/yr. 

Because of the uncertainty associated with the EPS analysis, 

the pumping rates were rounded to the nearest 0.01 (acre-ft/

acre)/yr. Furthermore, the model period of 1980–2011 used 

to estimate EPS was relatively wet, and thus EPS may be 

overestimated for future dry periods.

Estimated Equal-Proportionate-Share Pumping 

in Reach I

The initial annual groundwater-pumping rate for the 

EPS analysis was 0.38 (acre-ft/acre)/yr pumped continuously 

from every acre of the aquifer and increased incrementally by 

0.05 (acre-ft/acre)/yr. The results for the 20-year period are 

shown in figure 34, and the EPS rates calculated for all three 

time periods are listed in table 13. For a 20-year period, 50 

percent of the basin with less than or equal to 5 ft of saturated 

thickness was reached at a groundwater-pumping rate of 0.57 

(acre-ft/acre)/yr. Note that the EPS rate is rounded to 0.01 

(acre-ft/acre)/yr on the x-axis. Decreasing recharge 10 percent 

resulted in an annual rate of 0.53 (acre-ft/acre)/yr, and 

increasing the recharge 10 percent resulted in a rate of 0.60 

(acre-ft/acre)/yr. The final result of the EPS analysis for Reach 

I was an annual EPS groundwater-pumping rate between 0.53 

and 0.60 (acre-ft/acre)/yr as shown in figure 34.

Increasing the time period to 40 and 50 years caused 

the EPS pumping rate to decrease slightly to 0.54 and 0.53 

(acre-ft/acre)/yr, respectively (table 13). Both rates varied 

by approximately 0.05 (acre-ft/acre)/yr with a 10-percent 

change in recharge. Including all time periods and changes in 

recharge, the EPS pumping rate for Reach I varied between 

0.48 and 0.60 (acre-ft/acre)/yr.

20-year incremental pumping

Recharge increased 10 percent

Recharge decreased 10 percent

EXPLANATION

Note: The dashed lines represent the final equal-proportionate-share groundwater-pumping rate.

 The pumping rates above the graphs are rounded values.

50 percent of basin with less than

5 feet of saturated thickness

0.53 0.57 0.60

0.46 0.47 0.48 0.49 0.50 0.51 0.52 0.53 0.54 0.55 0.56 0.57 0.58 0.59 0.60 0.61 0.62 0.63 0.64

Continuous equal-proportionate-share groundwater-pumping rate, in acre-feet per acre per year

44

45

46

47

48

49

50

51

52

Percentage of basin with less than 5 feet of saturated thickness

Figure 34. Percentage of Reach I of the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma, with less than 5 feet 

of saturated thickness after 20 years of various levels of continuous equal-proportionate-share groundwater pumping and scaled 

recharge.
52 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

Table 13. Equal-proportionate-share (EPS) pumping for Reach I and Reach II for select time periods, Beaver-North Canadian River 

alluvial aquifer, northwestern Oklahoma.

[All units of pumping are acre-feet per acre per year]

Period 

(years)

Reach I EPS pumping rate Reach II EPS pumping rate

Recharge 

reduced by

10 percent

No change 

in recharge

Recharge 

increased by

10 percent

Recharge 

reduced by

10 percent

No change 

in recharge

Recharge 

increased by

10 percent

20 0.53 0.57 0.60 0.69 0.73 0.77

40 0.49 0.54 0.58 0.57 0.61 0.65

50 0.48 0.53 0.57 0.60 0.61 0.67

Estimated Equal-Proportionate-Share Pumping 

in Reach II

The initial annual groundwater-pumping rate for the 

EPS analysis was 0.33 (acre-ft/acre)/yr. The initial rate was 

increased incrementally by 0.05 (acre-ft/acre)/yr, and the 

number of cells with less than or equal to 5 ft of saturated 

thickness were tallied after 20, 40, and 50 years for each 

groundwater-pumping rate (table 13). For the 20-year EPS, 50 

percent of the basin with less than or equal to 5 ft of saturated 

thickness was reached at a rate of 0.73 (acre-ft/acre)/yr 

(fig. 35). As in the Reach I EPS analysis, recharge was varied 

by 10 percent to provide a range of EPS groundwater-pumping 

rates. Decreasing recharge 10 percent resulted in an annual 

rate of 0.69 (acre-ft/acre)/yr, and increasing the recharge 10 

percent resulted in a rate of 0.77 (acre-ft/acre)/yr as shown on 

figure 35. 

Increasing the time period for the EPS calculation to 

40 years resulted in a substantial decrease in the EPS pumping 

rate to 0.61 (acre-ft/acre)/yr (table 13). Increasing the time 

period to 50 years resulted in an EPS pumping rate that was 

indistinguishable from the 40-year EPS pumping rate of 

0.61 (acre-ft/acre)/yr. Including all time periods and changes 

in recharge, the EPS pumping rate for Reach II varied between 

0.57 and 0.77 (acre-ft/acre)/yr.

20-year incremental pumping

Recharge increased 10 percent

Recharge decreased 10 percent

EXPLANATION

Note: The dashed lines represent the final equal-proportionate-share groundwater-pumping rate.

 The pumping rates above the graphs are rounded values.

0.69 0.73 0.77

50 percent of basin with less than

5 feet of saturated thickness

Continuous equal-proportionate-share groundwater-pumping rate, in acre-feet per acre per year

0.64 0.66 0.68 0.70 0.72 0.74 0.76 0.78 0.65 0.67 0.69 0.71 0.73 0.75 0.77 0.79 0.80

44

45

46

47

48

49

50

51

52

Percentage of basin with less than 5 feet of saturated thickness

Figure 35. Percentage of Reach II of the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma, with less than 5 feet of 

saturated thickness after 20 years of various levels of continuous equal-proportionate-share groundwater pumping.
Effects of Projected Water Use and Drought 53

Effects of Projected Water Use and 

Drought 

The two reach models were run as predictive models for 

hypothetical future scenarios to evaluate the effects of projected 

water use, such as varying groundwater pumping rates, and 

prolonged drought on quantities of available water. Simulations 

included the climate variability present in the study period and 

provided assessments of potential effects on the hydrologic 

system under these conditions. Future water availability is 

defined in this study as the groundwater in storage, streamflow 

in the Beaver and North Canadian Rivers, and surface water 

stored in Fort Supply and Canton Lakes.

Projected Water Use

The calibrated numerical groundwater-flow models were 

used to estimate future effects of water use on groundwater 

resources of the Beaver-North Canadian River alluvial aquifer. 

Two water-use analyses were conducted: the first projected 

2011 water use for 50 years, and the second increased water 

use by a total of 32 percent over a hypothetical 50-year period 

as is projected in the OCWP (Oklahoma Water Resources 

Board, 2012). The 2011 water-use projection used the monthly 

groundwater pumping estimated for 2011 repeated for 50 years. 

To simulate a 32-percent increase in groundwater pumping 

over 50 years, the monthly groundwater-pumping rates for 

2011 were increased in a linear fashion so that after 50 years 

the annual groundwater pumping had increased by 32 percent.

The simulation period for increasing groundwater 

pumping in both models was constructed by using hydrologic 

conditions from a typical year on the basis of annual recharge 

as described in the “Groundwater Recharge” section of this 

report. The year with total recharge similar to the mean annual 

recharge for the model period (fig. 21) and pumping rates close 

to the mean annual rate (fig. 3) was 2005; 2008 recharge was 

very close to the mean recharge, but pumping was unusually 

low. Monthly recharge, ET, streamflow, and releases from lakes 

were used from 2005 for the entire model run. 

The effects of groundwater pumping in both reach models 

were evaluated by determining changes in groundwater storage 

over that period. To allow heads to stabilize, the model was 

run 1 year before the 50-year period, and the heads were saved 

at the end of that year. The heads in the models were saved 

again at the end of the 50-year period. The groundwater in 

storage was calculated by multiplying the saturated thickness 

in each model cell by the calibrated Sy in that cell. To calculate 

the change in groundwater in storage caused by groundwater 

pumping, the model for each reach was run once without 

pumping and again with groundwater pumping; the difference 

in water in storage between the end of the model runs provided 

an approximation of the effect of the groundwater pumping. 

In Reach I, the total water in storage at the end of 

the 50-year period with no groundwater pumping was 

approximately 2,220 thousand acre-ft. After the same period 

with groundwater pumping at 2011 rates, there were 2,140 

thousand acre-ft, a decrease of 3.6 percent (table 14). For 

Reach II after 50 years of pumping at the 2011 rate, there 

were 392 thousand acre-ft in storage with no groundwater 

pumping and 328 thousand acre-ft in storage with groundwater 

pumping, a decrease of 2.5 percent. 

With a 32-percent increase in groundwater pumping over 

the 50-year period, the water in storage at the end of the run in 

Reach I was 2,130 thousand acre-ft, a decrease of 4.0 percent. 

In Reach II, a 32-percent increase in groundwater pumping 

resulted in 379 thousand acre-ft of groundwater remaining in 

storage, a decrease of 3.3 percent (table 14).

Prolonged Drought

Several severe hydrologic droughts have affected the 

Beaver-North Canadian River alluvial aquifer since records 

were first collected in 1925. These droughts include the 

Dust Bowl drought (1929–41) and the droughts of 1952–56, 

1961–72, and 1976–81 (Shivers and Andrews, 2013). The 

period of this study includes the last 2 years of the 1976–81 

drought and below normal precipitation that began in 2011, 

which is considered drought conditions for this analysis. 

Across the State of Oklahoma, the only year with a greater 

negative departure from normal than 2011 was 1956, with 

2011 being the ninth driest year in the long-term streamflow 

record at the North Canadian River near Wetumka, Okla. 

(07242000), streamflow-gaging station (Shivers and Andrews, 

2013) located about 80 mi east of Reach II and shown on the 

inset map of figure 1.

Table 14. Changes in water in storage after 50 years of 

groundwater pumping at the 2011 rate and increasing the 2011 

rate by 32 percent over a 50-year period for the Beaver-North 

Canadian River alluvial aquifer, northwestern Oklahoma.

[All units thousands of acre-feet]

Reach Water in storage 

without pumping

Water in storage 

with pumping

Percent 

decrease

2011 pumping for 50 years

Reach I 2,220 2,140 3.6

Reach II 392 382 2.5

32 percent cumulative increase in pumping over 50 years

Reach I 2,220 2,130 4.0

Reach II 392 379 3.3
54 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

The primary source of water to the Beaver-North 

Canadian River alluvial aquifer hydrologic system is 

recharge from precipitation. Thus, a multiyear hydrologic 

drought is one of the most consequential climatic events for 

the Beaver-North Canadian River alluvial aquifer because 

the decreased precipitation results in decreased recharge. 

Models for both reaches were run in predictive mode over a 

hypothetical 10-year drought period by using two simulations. 

One simulation was used to calculate effects of drought on 

groundwater storage, and the other to calculate the effects 

of drought on streamflow and lake storage. Both simulations 

compared conditions during the hypothetical drought to the 

model run with calibrated model inputs.

Change in Groundwater Storage

In an unconfined aquifer such as the Beaver-North 

Canadian River alluvial aquifer, the volume of groundwater 

that can be pumped from storage is the product of the 

saturated thickness and the Sy of the aquifer (Fetter, 1994). 

Changes to inflow such as recharge and outflows such as 

pumping and discharge to streams can cause water to either 

be added to or removed from aquifer storage. To estimate the 

change in groundwater in storage resulting from a sustained 

hydrologic drought, the head and water in storage reference 

point was set as the end of the steady-state model for 1980. To 

simulate drought conditions, ET and recharge model inputs for 

2011 were repeated over the 10-year period. The year 2011 did 

not have the least amount of recharge, but precipitation during 

2011 was lower than any year in the model period of 1980–

2011 (fig. 7; fig. 8). Groundwater-pumping rates for 2011 were 

used during the hypothetical drought.

The drought simulation included an initial steady-state 

stress period, followed by 10 years (120 transient stress 

periods) under drought conditions. To ensure that the transient 

period showed the effect of drought on the hydrological 

system, the steady-state stress period was adjusted so that 

it was approximately the same recharge and ET as the first 

stress period of the drought. This adjustment removed any 

adjustment period that the transient model would incur if the 

steady-state conditions were substantially different from the 

first stress period of the drought.

Figure 36A shows that through the 10 years of simulated 

drought in Reach I, the decrease in recharge caused an annual 

deficit in the groundwater-flow system. This deficit caused 

seasonal changes to be superimposed on a linear decrease 

in groundwater in storage. The change in water in storage 

over the drought period was measured by using a 5-month 

moving average of stress-period volumes. The difference 

between the moving-average values at the beginning (3,580 

thousand acre-ft at stress period 4) and end of the simulation 

(3,340 thousand acre-ft at stress period 118) was 240 thousand 

acre-ft, a decrease of about 7 percent in Reach I (fig. 36A). 

Figure 36B shows a similar decline in the total volume of 

groundwater in storage in Reach II from 1,120 to 1,040 

thousand acre-ft, a difference of 80 thousand acre-ft or about 7 

percent during the simulated 10-year drought period.

This analysis of the effects of drought on the BeaverNorth Canadian River alluvial aquifer is approximate and is 

only representative of 1 drought year repeated over a decade. 

Actual droughts could potentially have a greater effect, and 

hydrological conditions would be expected to fluctuate. This 

analysis, however, does provide a generalized representation 

of how the system responds to drought conditions and that 

the loss of water in storage during such a simulated drought 

is substantial. The system could take several years to return to 

normal conditions.

Effects of Drought on Streamflow and Lake 

Storage

To simulate the effects of a prolonged drought on 

surface water, the calibrated model recharge was scaled 

down by 75 percent in both reach models during a period 

with relatively average hydrologic conditions (1994–2004). 

Changes in simulated streamflow in the North Canadian 

River at the Seiling streamflow-gaging station in Reach I and 

at the North Canadian River near Yukon, Okla. (07239700), 

streamflow-gaging station (referred to in the remainder of 

this report as the “Yukon streamflow-gaging station”) in 

Reach II and lake volumes at Canton Lake were analyzed by 

comparing nondrought and drought conditions. This analysis 

is approximate because simulated streamflow in the numerical 

groundwater-flow models represents changes in base flow 

from the Beaver-North Canadian River alluvial aquifer and 

did not include runoff peak flow. For this section, “simulated 

streamflow” refers to the combined simulated base flow and 

other inflows such as releases from Canton and Fort Supply 

Lakes upstream from the streamflow-gaging station.

At the Seiling streamflow-gaging station in Reach I, 

simulated streamflow during the hypothetical 1994–2004 

drought dropped to nearly no flow during low-flow periods 

(for example, during selected times in the summers of 

2001–3), and during high flows the flow decreased by over 

50 percent by the end of the drought (fig. 37). A moving 

average of the percentage change in streamflow decreased 

approximately 75 percent at the end of the drought period. The 

moving average of the simulated streamflow was still about 10 

percent less than the nondrought simulated streamflow at the 

end of the simulation period in 2011.
Effects of Projected Water Use and Drought 55

A

B

0 2 4 6 8 10

Years

0 2 4 6 8 10

Years

3,600

3,700

3,650

3,450

3,550

3,500

3,300

3,400

3,350

Simulated groundwater in storage, in thousands of acre-feet Simulated groundwater in storage, in thousands of acre-feet 

1,020

1,040

1,060

1,080

1,100

1,140

1,120

Total groundwater in storage

Five-month moving average of groundwater in storage

Total groundwater in storage

Five-month moving average of groundwater in storage

EXPLANATION

EXPLANATION

Figure 36. Change in groundwater in aquifer storage in A. Reach I, and B. Reach II during a hypothetical severe 10-year drought for 

the Beaver-North Canadian River alluvial aquifer, northwestern Oklahoma.
56 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought Percentage change in volume

-100

-50

0

Date

198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013

0

50

100

150

200

250

300

350

400

450

500

550

Streamflow, in cubic feet per second

Beginning of drought

End of drought

Simulated streamflow without drought

Simulated streamflow with drought (1994–2004)

Percentage change

Percentage change moving average

EXPLANATION

Streamflow at North Canadian River near Seiling,

Oklahoma (07238000), streamflow-gaging station—

Location of streamflow-gaging station shown on figure 1

Figure 37. Changes in streamflow at the North Canadian River near Seiling, Oklahoma (07238000), streamflow-gaging station during 

a hypothetical drought, 1994–2004. “Simulated streamflow” refers to the combined simulated base flow and other inflows such as lake 

streamflow releases.

Drought analysis for Reach II was performed on the 

North Canadian River by using simulated streamflow at the 

Yukon streamflow-gaging station. Effects of the hypothetical 

drought were less pronounced at the station than was apparent 

in Reach I at the Seiling streamflow-gaging station. Simulated 

high streamflow at the Yukon streamflow-gaging station 

decreased more than 20 percent by the end of the hypothetical 

1994–2004 drought, and simulated low flows decreased 

by more than 60 percent during the fall of 2003 (fig. 38). 

A moving average of the percentage change in simulated 

streamflow decreased by approximately 35 percent at the 

end of the hypothetical drought in 2004 and recovered to a 

decrease of only about 5 percent by 2011 (fig. 38). Effects 

of simulated hypothetical drought may have been less at the 

Yukon streamflow-gaging station because of released flow 

from Canton Lake that countered the decrease in base flow. 

In Reach I, the model runs under hypothetical drought 

conditions during 1994–2004 showed a substantial decrease 

in simulated Canton Lake storage compared to nondrought 

conditions (fig. 39). After the hypothetical drought began, 

water volume progressively dropped until the drought ended 

in 2004. Simulated Canton Lake storage was still less than 50 

percent of the nondrought simulated lake storage at the end of 

the model simulation in 2011. By the end of the hypothetical 

drought, the volume in Canton Lake had decreased by 83 

percent. Effects of drought were related to lower base flow to 

the Beaver and North Canadian Rivers as seen in the effects 

of drought on simulated streamflow at the Seiling streamflowgaging station and thus flow to the lake. This analysis may 

overestimate the decrease in lake storage because the lake 

operators will stop releasing water from the lake when the lake 

stage reaches a specified level.
Effects of Projected Water Use and Drought 57

Beginning of drought

End of drought

Percentage change in volume

–100

–40

–20

–80

–60

0

Date

198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013

0

100

200

300

400

500

600

700

800

900

1,000

Streamflow, in cubic feet per second

Simulated streamflow without drought

Simulated streamflow with drought (1994–2004)

Percentage change

Percentage change moving average

EXPLANATION

Streamflow at North Canadian River near Yukon,

Oklahoma (07239700), streamflow-gaging station—

Location of streamflow-gaging station shown on figure 1

Figure 38. Changes in streamflow at the North Canadian River near Yukon, Oklahoma (07239700), streamflow-gaging station during a 

hypothetical drought, 1994–2004. “Simulated streamflow” refers to the combined simulated base flow and other inflows such as lake 

streamflow releases. 

Model Limitations

All models are constructed with a limited amount of data 

and, thus, are necessarily simplifications of actual systems. 

When creating a model of a large area, it is necessary to make 

more simplifications than when creating models of smaller 

areas. Model limitations are a consequence of uncertainty 

in three basic aspects of the model, including inadequacies, 

inaccuracies, or simplifications in (1) observations used in 

the model, (2) representation of geologic complexity in the 

hydrogeologic framework, and (3) representation of the 

groundwater system in the model. It is important to understand 

how these characteristics limit the use of the model.

Head observations used to calibrate the models were well 

distributed across the Beaver-North Canadian River alluvial 

aquifer during 1980 and 2011, but during the intervening 

years, head data were more sparse, and though the models 

reproduced sampled heads fairly accurately, the sparse 

temporal nature of the data introduces uncertainty in future 

model projections.

This model was constructed to simulate the period 

1980–2011, and all projections were simulated by using data 

from this period. The 50-year transient simulations project 

the analysis 18 years beyond 2011 by using hydrologic data 

from 1980 to 1998, and it is assumed that future climate will 

be similar to 1980–98, which did not include any of the severe 

drought periods such as those that occurred during the 1930s, 

1950s, or 1976–81. Thus, the EPS and water-use scenarios 

simulated in this report are biased by the climate during the 

period of the study presented in this report.

The parameters and boundary conditions for the models 

used in this report were generalized for large areas and are not 

to be used for local analyses. Though the calibration process 

produced parameterized models that matched observed 

groundwater heads very closely, the two parameters that the 

simulated heads were most sensitive to and were the primary 

parameters for calibration (Kh and recharge) are correlated. 

With correlated parameters, there are multiple combinations of 

the parameter values that will produce the same result, and the 

result is not unique. Thus, though the parameters in the models 

were restricted to reasonable values, without additional direct 

parameter measurements there is considerable uncertainty in 

local results.
58 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought Beginning of drought End of drought Percentage change in volume

–100

–50

0

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

Lake volume, in acre-feet

Date

198419851986198719881989199019911992199319941995199619971998199920002001200220032004200520062007200820092010201120122013

Simulated lake volume without drought

Simulated lake volume with drought (1994–2004)

Percentage change

EXPLANATION

Lake storage in Canton Lake—

Location of lake shown on figure 1

Figure 39. Simulated changes in Canton Lake water in storage during a hypothetical drought, 1994–2004.

Summary

Across northwestern Oklahoma, the Beaver and North 

Canadian Rivers provide water for numerous uses and are 

important sources of the water that is stored in Canton Lake. 

The Beaver and North Canadian Rivers are an important 

conveyance for water released from Canton Lake and diverted 

to Lake Hefner Canal for part of the Oklahoma City, Okla., 

public water supply. The Beaver-North Canadian River 

alluvial aquifer is hydraulically connected to the Beaver 

and North Canadian Rivers, and on the basis of base-flow 

estimates, more than half of the streamflow in the river 

comes from the Beaver-North Canadian River alluvial 

aquifer. The Beaver-North Canadian River alluvial aquifer 

provides groundwater resources for public water supplies at 

several small cities, domestic wells, irrigation, nonirrigation 

agriculture, industry, mining, recreation, commercial, and 

other uses.

This report describes the hydrogeologic framework 

and groundwater flow in the Beaver-North Canadian River 

alluvial aquifer in northwestern Oklahoma and construction 

and results of a numerical groundwater-flow model used to 

simulate the groundwater-flow system from 1980 through 

2011 and for various future scenarios. Predictive simulations 

include the calculation of the equal-proportionate-share 

(EPS) groundwater-pumping rate and effects of groundwater 

pumping and severe droughts on groundwater in storage and 

surface water.

The Beaver-North Canadian River alluvial aquifer 

is a long, narrow alluvial aquifer that spans variations in 

climate for approximately 175 miles from the Oklahoma 

Panhandle to the western margin of Oklahoma City in central 

Oklahoma. Analysis of the Beaver-North Canadian River 

alluvial aquifer was divided into Reach I above the Canton 

Dam and Reach II downstream from the dam. Land use on 

the Beaver-North Canadian River alluvial aquifer was mostly 

upland grasses/forbs and planted/cultivated agriculture and 

did not change substantially during the period of study. Mean 

annual precipitation during the period of study varied from 

23.5 inches per year in the semiarid west to 35.7 inches per 

year in the subhumid east. Mean monthly precipitation at 

the Woodward weather station in Reach I and the Watonga 

weather station in Reach II showed strong seasonality and 

slightly higher precipitation at Watonga. Wet and dry periods 

were delineated by deviations of total annual precipitation 

from the mean annual precipitation at Woodward and 

Watonga. Both stations experienced dry periods coincident 

with regional hydrologic droughts and dry periods after 2010.
Summary 59

Surface-water use for the Beaver and North Canadian 

Rivers and groundwater use for the Beaver-North Canadian 

River alluvial aquifer are managed by the Oklahoma Water 

Resources Board (OWRB). The groundwater-use analysis 

full period of record, 1967–2011, was divided into two 

sub-intervals, 1970–80 and 1981–2011, because of varying 

groundwater use. Groundwater use in Reach I and Reach II 

was substantially greater from 1970 to 1980 compared to the 

rest of the period. The total mean annual groundwater use 

in Reach I was 15,309 acre-feet per year (acre-ft/yr) during 

1967–2011; 20,724 acre-ft/yr during 1970–80, and 13,739 

acre-ft/yr during 1981–2011. Total mean annual groundwater 

use in Reach II was similar but slightly less than in Reach I, 

with 14,098 acre-ft/yr during 1967–2011; 19,963 acre-ft/yr 

during 1970–80; and 12,285 acre-ft/yr during 1981–2011.

Irrigation composed 72 percent of groundwater use 

in Reach I and 48 percent of groundwater use in Reach II 

during the 1967–2011 period. Public water supply was a 

much smaller proportion of total groundwater use in Reach 

I (15 percent) than in Reach II (39 percent). The proportion 

of groundwater use for power was 10 percent in Reach I 

and 5.2 percent in Reach II. All other water-use categories 

in Reach I only composed 2.2 percent of groundwater use 

in Reach I. In Reach II, industrial, mining, and commercial 

categories combined accounted for 4.4 percent of groundwater 

use; recreation, fish, and wildlife water use accounted for 

2.3 percent; and nonirrigated agriculture and other accounted 

for 1.5 percent.

Only irrigation and public water supply were used in 

the numerical groundwater-flow models. During the period 

of groundwater-flow models (1980–2011), there were 301 

irrigation and 57 public water-supply wells that were tied to 

active groundwater permits. There were 58 temporary and 

permanent surface-water diversions used in the model, with 

a total of approximately 1,240 acre-ft/yr; 70 acre-ft/yr from 

Reach I and 1,170 acre-ft/yr from Reach II.

Fort Supply and Canton Lakes impound streamflow for 

release during dry months; Canton Lake releases water that is 

diverted to the Lake Hefner Canal near the eastern end of the 

Beaver-North Canadian River alluvial aquifer to augment the 

public water supply in Oklahoma City. Streamflow into the 

study area from the Beaver River decreased from 1978 to 1994 

because of groundwater depletion in the High Plains aquifer 

to the west, which reduced base flow upstream. Base flow 

along the Beaver and North Canadian Rivers in the study area 

is variable, but overall the Beaver and North Canadian Rivers 

are gaining streams, and streamflow increases downstream. 

The only perennial tributary to the North Canadian River is 

Wolf Creek, which flows from the west, outside the extent of 

the Beaver-North Canadian River alluvial aquifer. Wolf Creek 

flows into Fort Supply Lake and the North Canadian River in 

Reach I.

The Beaver-North Canadian River alluvial aquifer is an 

unconsolidated Quaternary-age valley-bottom and terrace 

alluvial deposit that overlies low-permeability Permian-age 

bedrock. The Beaver-North Canadian River alluvial aquifer 

included the underlying Tertiary-age Ogallala Formation in the 

farthest northwestern extent of the aquifer. The mean saturated 

thickness of the Beaver-North Canadian River alluvial aquifer 

was estimated to be 36 ft in Reach I and 29 ft in Reach II. The 

maximum saturated thickness of the Beaver-North Canadian 

River alluvial aquifer was estimated to be 308 ft in Reach I 

and 86 ft in Reach II. The thickest parts of Reach I included 

the underlying Ogallala Formation.

Groundwater flow in the Beaver-North Canadian River 

alluvial aquifer was generally from northwest to southeast 

along the trend of the aquifer and toward the Beaver and 

North Canadian Rivers, and recharge in upland areas along 

the eastern margin of the aquifer produced a general flow 

from east to west; in some local areas in the uplands, recharge 

created a groundwater divide causing groundwater to flow 

toward the eroded northeastern boundary of the aquifer. 

Observation wells measured over the period of study on the 

Beaver-North Canadian River alluvial aquifer show a minor 

upward trend in groundwater head.

The hydraulic parameters of the Beaver-North Canadian 

River alluvial aquifer are highly variable. Published aquifer 

tests and laboratory tests of aquifer materials were used in 

this report to estimate horizontal hydraulic conductivity 

(Kh) and specific yield (Sy) for borehole-log lithologic 

descriptions to interpolate properties throughout the entire 

Beaver-North Canadian River alluvial aquifer. The Kh and Sy 

were then adjusted during numerical groundwater-flow model 

calibration. Calibrated model Kh was estimated to range from 

4 to 279 feet per day (ft/d). The mean Kh was 70 ft/d in Reach 

I and 92 ft/d in Reach II.

Base flow in both reaches was analyzed by using 

published studies, one seepage run performed for this study, 

and base-flow separation analysis of streamflow data in Reach 

I. Seepage run measurements from 1979 and 2012 in Reach 

I indicated that base flow was very similar at the two times 

and that the Beaver and North Canadian Rivers upstream 

from Canton Lake was generally gaining except for several 

reaches upstream from Wolf Creek. The mean base flow from 

seepage runs was 31 cubic feet per second (ft3

/s). Base-flow 

separation analysis indicated that the mean base-flow index for 

the Beaver and North Canadian Rivers in Reach I was 0.63, 

and the total base-flow flow in Reach I during the period of 

study was 69,000 acre-feet (acre-ft). Base-flow separation was 

not performed on Reach II because of flow control by Canton 

Dam. One seepage run in Reach II indicated that the North 

Canadian River gained a total of 14.2 ft3

/s between Canton 

Lake and the Lake Hefner Canal diversion.

Groundwater recharge was estimated by using a soilwater-balance (SWB) model. This model produced monthly 

and annual arrays of recharge across the Beaver-North 

Canadian River alluvial aquifer. Total recharge was found 

to be most sensitive to precipitation and root-zone depth. A 

10-percent increase in daily precipitation applied during the 

model run resulted in a 26-percent increase in total recharge, 

and a 10-percent decrease in precipitation caused a 23-percent 

decrease in recharge. Recharge was very sensitive to root-zone 
60 Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought

depth as well. Recharge decreased 9 percent with a 10-percent 

increase in root-zone depth and increased 8 percent with a 

10-percent decrease in root-zone depth. The estimated mean 

annual recharge from the SWB model was 136,400 acre-ft in 

Reach I and 82,400 acre-ft in Reach II, for a total of 218,800 

acre-ft. The total estimated recharge from 1980 to 2011 was 

approximately 4,350 thousand acre-ft for Reach I and 2,600 

thousand acre-ft for Reach II.

Local groundwater-recharge estimates were made at 

two sites in Reach I located at observation wells near the 

North Canadian River and streamflow-gaging stations with 

precipitation gages by using the water-table fluctuation 

method. The Woodward site was at observation well OW-4 

and near the streamflow-gaging station on the North Canadian 

River at Woodward, Okla. (07237500). The Seiling site was 

at observation well OW-5, which was near the streamflowgaging station on the North Canadian River near Seiling, Okla. 

(07238000). At both wells OW-4 and OW-5, instruments 

collected continuous water-level measurements for parts of 

2012 and 2013. Water-level fluctuations were compared to 

precipitation and stream-stage measurements at both sites 

to estimate groundwater recharge. The sites were not close 

enough to the North Canadian River streamflow-gaging 

stations to determine seasonal changes in base flow, but both 

sites were generally gaining base flow. The total precipitation 

and recharge for the Woodward and Seiling sites were 

calculated for the water year 2013. The Woodward site had 

a total of 14.18 inches (in.) of precipitation, and 6.3 in. of 

recharge were calculated, for 44 percent of precipitation. The 

mean percentage of precipitation that was estimated to become 

recharge in the SWB model for the period 1980–2011 at that 

location was 9.2 percent, although adjacent SWB-model cells 

were as high as 20 percent of precipitation. The Seiling site 

had a total of 26.84 in. of precipitation during the water year 

2013, and a total of 6.9 in. of recharge was estimated, for 

25.9 percent of precipitation. At the Seiling site, the mean 

percentage of precipitation that became recharge in the SWB 

model for the period 1980–2011 was 23.0 percent. 

Other water-budget categories for the Beaver-North 

Canadian River alluvial aquifer included well pumping, 

evapotranspiration (ET) by plants, seeps and springs, and 

lateral groundwater flow to and from other geological units. 

Only the well pumping for irrigation and public water supply 

was directly quantified in this report. The total volume of 

water pumped by wells during the study period was 14,500 

acre-ft in Reach I and 10,100 acre-ft in Reach II, for a total of 

24,600 acre-ft.

The numerical groundwater-flow model objectives 

included simulating the transient groundwater flow in both 

reaches of the Beaver-North Canadian River alluvial aquifer 

from 1980 to 2011 to address long-term groundwater pumping 

and drought scenarios, including calculation of the EPS 

pumping rates. A steady-state model for 1980 and a transient 

model using monthly stress periods from 1981 to 2011 were 

constructed for both reaches of the Beaver-North Canadian 

River alluvial aquifer. Models were calibrated by using 

groundwater-head observations and adjusting recharge from 

the SWB model and Kh interpolated from published aquifer 

tests and lithologic borehole logs. The water budgets from the 

numerical flow model and the conceptual flow model showed 

that recharge in both reaches was much greater than stream 

base flow, and the balance was discharged primarily to ET.

Several analyses were performed by using the numeric 

groundwater-flow models as predictive models, including 

estimating the EPS pumping rate for both reaches. The EPS 

is defined by the OWRB as an annual per-acre groundwaterpumping rate that will reduce saturated thickness in half of the 

aquifer to 5 feet or less over a period of 20 years; additional 

estimates were made for periods of 40 and 50 years. A 

range of values was calculated by determining the EPS rate 

with recharge reduced by 10 percent and increased by 10 

percent. Other analyses included using models to estimate the 

effects of groundwater pumping and a prolonged drought on 

groundwater in storage and streamflow and lake storage of 

water. 

For a 20-year period, the EPS pumping rate was found 

to be 0.57 (0.53–0.60) acre-feet per acre per year ([acre-ft/

acre]/yr) in Reach I and 0.73 (0.69–0.77) (acre-ft/acre)/yr in 

Reach II. For a 40-year period, the annual EPS pumping rate 

was determined to be 0.54 (0.49–0.58) (acre-ft/acre)/yr in 

Reach I and 0.61 (0.57–0.65) (acre-ft/acre)/yr in Reach II. For 

a 50-year period, the EPS pumping rate was determined to be 

0.53 (0.48–0.57) (acre-ft/acre)/yr in Reach I and 0.61 (0.60–

0.67) (acre-ft/acre)/yr in Reach II.

Groundwater pumping at 2011 rates for 50 years caused 

a decrease of groundwater in aquifer storage by 3.6 percent 

in Reach I and 2.5 percent in Reach II. Increasing the 2011 

groundwater-pumping rate to a cumulative increase of 32 

percent over 50 years resulted in a decrease in groundwater 

in storage of 4.0 percent in Reach I and 3.3 percent in 

Reach II.

Drought scenarios used the reach models to simulate a 

hypothetical 10-year severe drought. A 10-year period using 

recharge and ET rates from the dry year of 2011 caused a 

cumulative decrease of groundwater in storage of about 

7 percent in Reach I and 7 percent in Reach II. The transient 

models were also used to simulate a hypothetical drought that 

was assumed to cause a 75-percent decrease in recharge for 

the 10-year period 1994–2004, and the effects on surfacewater storage in Canton Lake and streamflow in the North 

Canadian River were estimated. Mean streamflow at the 

Seiling streamflow-gaging station in Reach I decreased by 

75 percent at the end of the drought period and had recovered 

to 10 percent of nondrought streamflow by the end of the 

simulation in 2011. Mean streamflow at the Yukon streamflowgaging station in Reach II decreased by approximately 35 

percent at the end of the drought and recovered to a decrease 

of about 5 percent by 2011. Recovery of flow at the Yukon 

streamflow-gaging station may have been aided by releases 

from Canton Lake. At the end of the hypothetical drought, 

Canton Lake storage had decreased by 83 percent and did not 

recover by the end of 2011. 
References Cited 61

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Ryter and Correll—Hydrogeological Framework, Numerical Simulation of Groundwater Flow, and Effects of Projected Water Use and Drought—SIR 2015–5183, ver. 1.1

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