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Comparison of Hydrologic Data and Water Budgets Between 2003–08 and 2018–23 for the Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Shana L. Mashburn, Evin J. Fetkovich, Hayden A. Lockmiller, Chloe Codner, Ethan A. Kirby, Isaac A. Dale · U.S. Geological Survey

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Prepared in cooperation with the Oklahoma Water Resources Board and the Oka’ Institute

Comparison of Hydrologic Data and Water Budgets Between 2003–08 and 2018–23 for the Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Scientific Investigations Report 2025–5011

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

Cover: Top, Pennington Creek near Reagan, Oklahoma. Photograph by Grant Graves, U.S. Geological Survey (USGS). Middle, Byrds Mill Spring near Fittstown, Oklahoma. Photograph by Hayden A. Lockmiller, USGS. Bottom, Blue River near Connerville, Oklahoma. Photograph by Hayden A. Lockmiller, USGS.

Comparison of Hydrologic Data and Water Budgets Between 2003–08 and 2018–23 for the Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma By Shana L. Mashburn, Evin J. Fetkovich, Hayden A. Lockmiller, Chloe Codner, Ethan A. Kirby, Isaac A. Dale, and Colin A. Baciocco

Prepared in cooperation with the Oklahoma Water Resources Board and the Oka’ Institute

Scientific Investigations Report 2025–5011

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

U.S. Geological Survey, Reston, Virginia: 2025

For more information on the USGS—the Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment—visit https://www.usgs.gov or call 1–888–392–8545. For an overview of USGS information products, including maps, imagery, and publications, visit https://store.usgs.gov/ or contact the store at 1–888–275–8747. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner. Suggested citation: Mashburn, S.L., Fetkovich, E.J., Lockmiller, H.A., Codner, C., Kirby, E.A., Dale, I.A., and Baciocco, C.A., 2025, Comparison of hydrologic data and water budgets between 2003–08 and 2018–23 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma: U.S. Geological Survey Scientific Investigations Report 2025–5011, 61 p., https://doi.org/10.3133/sir20255011. Associated data for this publication: Mashburn, S.L., Kirby, E.A., and Wagner, D.L., 2025, Soil-Water-Balance model and data for Phase 1 (2003–08) and Phase 2 (2018–23) hydrologic and water-budget analyses of the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma, 2019–22: U.S. Geological Survey data release, https://doi.org/10.5066/P14UXYVV. ISSN 2328-0328 (online)

iii

Acknowledgments This study of the hydrology of the eastern part of the Arbuckle-Simpson aquifer was possible through cooperation with the Oklahoma Water Resources Board of the State of Oklahoma and The Oka’ Institute at East Central University. Additional collaborating partners were the U.S. Fish and Wildlife Service; the National Park Service; the U.S. Environmental Protection Agency, Robert S. Kerr Environmental Research Center; The Chickasaw Nation; The Choctaw Nation of Oklahoma; and Vulcan Materials Company. The authors would like to thank the Blue River Foundation of Oklahoma for providing input, ideas, information, and time to make this project a success. The authors also thank the many landowners who granted access for collecting data. This report and study would not have been possible without their assistance. The authors would also like to thank the U.S. Geological Survey staff who have dedicated their time to the success of this project: Jason Lewis, Rick Hanlon, Kevin Smith, Levi Close, Nicholas Pierson, Kyle Cothren, Carol Becker, Stephen Bradford, Steven Smith, Ian Rogers, MaryKate Higginbotham, Natalie Gillard, Cory Russell, Amy Morris, and Nicole Gammill.

Contents Acknowledgments��iii Abstract��1 Introduction��1 Study Area��2 Purpose and Scope��3 Geology and Hydrogeologic Units��3 Geologic History��3 Structural Geology��6 Hydrogeologic Units��7 Previous Hydrologic Studies and Phase 1 Study of the Arbuckle-Simpson Aquifer��9 Hydrologic Data Comparison: Phase 1 to Phase 2��9 Climate��9 Streamflow Monitoring��12 Base Flow��18 Net Streamflow Gains and Losses��18 Springflow Monitoring��21 Continuous Springflow Monitoring��21 Discrete Springflow Measurements��29 Groundwater Monitoring��29 Potentiometric Surfaces��31 Recharge��36 RORA Recession-Curve Displacement Method��36 Soil-Water-Balance Code��38 Groundwater Withdrawals and Water Use��41 Groundwater Withdrawals��41 Consumptive Water Use at Producing Mines��41 Water-Budget Comparison: Phase 1 to Phase 2��45 Future Studies and Monitoring Data��50 Summary��50 References Cited��52 Appendix 1. Spring Discharge Measured in the Arbuckle-Simpson Aquifer��58

Figures 1. Map of study area showing the eastern part of the Arbuckle-Simpson aquifer, U.S. Geological Survey streamgages where streamflow data were collected for the Phase 1 (2003–08) and Phase 2 (2018–23) studies, climate stations where precipitation data were collected, and surface-water diversions and permitted wells, south-central Oklahoma, 2003–23��4 2. Map showing geologic units exposed at the surface in the study area for the eastern part of the Arbuckle-Simpson aquifer, with locations of U.S. Geological Survey (USGS) groundwater monitoring stations where data were collected for the Phase 2 (2018–23) study and USGS spring gages where spring discharges were measured, south-central Oklahoma��5 3. Stratigraphic chart showing notable geologic and hydrogeologic units in the eastern part of the Arbuckle-Simpson aquifer��8 4. Graphs showing annual mean precipitation with periods of above or below mean annual precipitation and annual mean temperature data with periods of above or below the mean annual temperature, south-central Oklahoma, 1895–2022��10 5. Graphs showing mean monthly precipitation and mean monthly temperature for south-central Oklahoma Climate Division 8 during 1895–2022, 2003–08, and 2018–22��11 6. Graphs showing annual mean base-flow estimates and mean annual base-flow for selected streams crossing the eastern part of the Arbuckle-Simpson aquifer Phase 1 (2003–08) to Phase 2 (2018–23), south-central Oklahoma��19 7. Hydrograph showing streamflow before, during, and after augmentation from producing-mine discharges upstream from U.S. Geological Survey streamgage 07331200 Mill Creek near Mill Creek, Oklahoma, March 2023–April 2024��20 8. Map showing synoptic base-flow measurement sites and gaining and losing stream reaches crossing the surficial extent of the rocks that contain the eastern part of Arbuckle-Simpson aquifer, south-central Oklahoma, January 24–31, 2022��27 9. Map showing synoptic base-flow measurement sites and gaining and losing stream reaches crossing the surficial extent of the rocks that contain the eastern part of Arbuckle-Simpson aquifer, south-central Oklahoma, February 28–March 1, 2023��28 10. Graphs showing discharge and spring recession curves classified by flow regime and precipitation for Antelope Spring, Byrds Mill Spring, and Sheep Creek Spring, south-central Oklahoma, 2014–17��30 11. Graphs showing depth to water and daily precipitation for U.S. Geological Survey monitoring wells completed in the Arbuckle Group and the Simpson Group, south-central Oklahoma, 2003–23��33 12. Map showing potentiometric surface of the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma, February 2022��34 13. Map showing potentiometric surface of the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma, February 2023��35 14. Map showing spatially distributed mean annual recharge computed by using the Soil-Water-Balance code for the eastern Arbuckle-Simpson aquifer study area, south-central Oklahoma, 2019–22��40

vii

15. Graphs showing reported groundwater use by type and permitted groundwater use during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��42 16. Graphs showing water budgets for the eastern part of the Arbuckle-Simpson aquifer during Phase 1 numerical model period (October 2003 to September 2008) and Phase 2 conceptual model period (2018–22 calendar years), south-central Oklahoma��47

Tables 1.

2. 3. 4. 5. 6.

10.

11. 12.

13.

Annual precipitation at Mesonet climate stations and the mean precipitation recorded by those Mesonet stations each year, 1995–2022, south-central Oklahoma��13 Monthly precipitation recorded by the Blue River NEON station, September 2018–June 2022, Johnston County, Oklahoma��14 Periods of record for U.S. Geological Survey streamgages in and near the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��15 Summary statistics for streamgages used during Phase 1 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��16 Changes in daily streamflow between Phase 1 and Phase 2 for the eastern part of the Arbuckle-Simpson aquifer, Oklahoma��17 Discrete discharge measurements made as part of the 2022 and 2023 seepage runs in and near the study area for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��22 Differences in mean discharge at spring sites between historical period of record and 2018–23 (Phase 2), eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��31 Periods of record for continuous groundwater monitoring wells completed in the Arbuckle or Simpson Group across the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��32 Quarterly recharge calculated for U.S. Geological Survey streamgage 07332390 at Blue River near Connerville, Oklahoma, for Phase 1 (1977–2008) and Phase 2 (2018–22) periods��37 Quarterly recharge calculated for U.S. Geological Survey streamgage 07331300 at Pennington Creek near Reagan, Oklahoma, for Phase 1 (2004–08) and Phase 2 (2018–22)��38 Annual reported groundwater use during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma��43 Summary statistics of annual consumptive water-use estimates, and sum of water pumped from mine pits, water discharged to streams, and water injected into the subsurface from producing mines in the Arbuckle-Simpson aquifer, south-central Oklahoma, 2019–22��45 Phase 2 conceptual water budget for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma (2018–22)��49

viii viii

Conversion Factors U.S. customary units to International System of Units

Multiply

To obtain

Length inch (in.)

2.54

centimeter (cm)

inch (in.)

25.4

millimeter (mm)

foot (ft)

0.3048

meter (m)

mile (mi)

1.609

kilometer (km)

Area acre

4,047

square meter (m2)

acre

0.4047

hectare (ha)

acre

0.4047

square hectometer (hm2)

acre

0.004047

square kilometer (km2)

square mile (mi2) square mile (mi2)

259.0 2.590

hectare (ha) square kilometer (km2)

Volume gallon (gal)

3.785

liter (L)

gallon (gal)

0.003785

cubic meter (m3)

gallon (gal)

3.785

cubic decimeter (dm3)

acre-foot (acre-ft) acre-foot (acre-ft)

1,233 0.001233

cubic meter (m3) cubic hectometer (hm3)

Flow rate acre-foot per day (acre-ft/d) acre-foot per year (acre-ft/yr)

0.01427 1,233

cubic meter per second (m3/s) cubic meter per year (m3/yr)

acre-foot per year (acre-ft/yr)

0.001233

cubic hectometer per year (hm3/yr)

foot per year (ft/yr)

0.3048

meter per year (m/yr)

cubic foot per second (ft3/s)

0.02832

cubic meter per second (m3/s)

cubic foot per day (ft3/d)

0.02832

cubic meter per day (m3/d)

gallon per minute (gal/min)

0.06309

liter per second (L/s)

inch per year (in/yr)

25.4

millimeter per year (mm/yr)

Hydraulic gradient foot per mile (ft/mi)

0.1894

meter per kilometer (m/km)

Temperature in degrees Fahrenheit (°F) may be converted to degrees Celsius (°C) as follows: °C = (°F – 32) / 1.8.

Datums 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.

ix ix

Abbreviations bls

below land surface

DEM

digital elevation model

EPA

U.S. Environmental Protection Agency

NCEI

National Centers for Environmental Information

NPDES

National Pollutant Discharge Elimination System

NWIS

National Water Information System

OWRB

Oklahoma Water Resources Board

SWB

Soil-Water-Balance code

USGS

U.S. Geological Survey

Abstract

Introduction

The Arbuckle-Simpson aquifer is divided spatially into three parts (eastern, central, and western). The largest groundwater withdrawals are from the eastern part of the Arbuckle-Simpson aquifer, which provides water to approximately 39,000 people in Ada and Sulphur, Oklahoma, and surrounding areas. The Arbuckle-Simpson aquifer, including the eastern part, is designated a sole source aquifer for its service area. Based primarily on data collected between 2003 and 2008, a series of comprehensive hydrologic studies of the Arbuckle-Simpson aquifer was published to provide the information necessary to perform groundwater-flow model simulations so that the Oklahoma Water Resources Board could determine how much water could be withdrawn from the aquifer while maintaining flow to springs and streams. As part of the Phase 1 studies, an aquifer water budget was developed from a numerical model for the period 2003–08. For this report, Phase 1 refers to the 2003–08 data collection period, although for some of the analyses, data collected prior to 2003 were used to inform model development work. Allocation of water from this aquifer was then established by the Oklahoma Water Resources Board in 2013. Additional well-spacing rules were also established by the Oklahoma Water Resources Board for sensitive sole source groundwater basins. To determine how the water budget for the eastern part of the Arbuckle-Simpson aquifer has changed over time, recently collected hydrologic data (2018–23) were compared to data collected during 2003–08. The analysis of changes in the aquifer water budget from 2003–08 to 2018–23 could help resource managers better understand changes in the overall balance of water in storage and the potential effects on streamflow, changes in groundwater levels, and the effects of different water uses in the aquifer area on available water in the eastern part of the Arbuckle-Simpson aquifer and streams overlying the eastern part of the Arbuckle-Simpson aquifer.

Based primarily on data collected between 2003 and 2008, a series of comprehensive hydrologic studies of the Arbuckle-Simpson aquifer in south-central Oklahoma was conducted between 2003 and 2011. For this report, “Phase 1” refers to an initial 2003–08 data collection period, although for some analyses, data collected prior to 2003 were used to inform model development. Results from Phase 1 provided information necessary to perform groundwater-flow model simulations that, in addition to characterizing groundwater resources in the study area, helped inform the Oklahoma Water Resources Board (OWRB) in their decisions regarding how much water could be withdrawn from the aquifer while maintaining flow to springs and streams. The rocks that contain the karstic Arbuckle-Simpson aquifer consist primarily of uplifted carbonates exposed at the surface across an area of approximately 520 square miles (mi2) (332,800 acres) in Carter, Coal, Johnston, Murray, and Pontotoc Counties (Christenson and others, 2011). In addition to being uplifted, the rocks that contain the Arbuckle-Simpson aquifer are characterized by large fault displacements and folded structures. The Arbuckle-Simpson aquifer is divided spatially into three parts (eastern, central, and western). Christenson and others (2011, p. 4) noted that most groundwater withdrawals are from the eastern part of the Arbuckle-Simpson aquifer, which among other uses, provides water to Ada and Sulphur, Okla., and surrounding areas. The largest streams and springs (by flow volume) also emanate from the eastern part of the Arbuckle-Simpson aquifer. The U.S. Environmental Protection Agency (EPA) designated the Arbuckle-Simpson aquifer, including the eastern part of the Arbuckle-Simpson aquifer, as a “sole source aquifer” in 1989 (EPA, 1989). The EPA defines a sole source aquifer as one where “the aquifer supplies at least 50 percent of the drinking water for its service area” and “there are no reasonably available alternative drinking water sources should the aquifer become contaminated” (EPA, 2024a).

2 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma The OWRB manages the use of groundwater and surface-water resources under separate appropriation doctrines, according to Oklahoma water law. Surface water is considered to be publicly owned and subject to appropriation by the OWRB (Oklahoma State Legislature, 2023a). Conversely, groundwater is considered a private property right that belongs to the overlying surface owner, but permits from the OWRB are required for most uses of groundwater, except for most domestic uses (Oklahoma State Legislature, 2023b). In response to concerns about potential transfers of groundwater from the Arbuckle-Simpson aquifer to central Oklahoma, the Oklahoma Senate passed Senate Bill 288 (2003), which imposed a moratorium on the issuance of any temporary groundwater permit for municipal or public water-supply use outside of any county that overlies a “sensitive sole source groundwater basin” until the OWRB completes a hydrologic study and approves a maximum annual yield (the maximum amount of water that can be withdrawn from a specific groundwater basin in any year). This moratorium and hydrologic study requirement were implemented to help ensure that any permit for the removal of water from the groundwater basin will not reduce the natural flow of water from springs or streams emanating from the basin (OWRB, 2003). As a result of Senate Bill 288, comprehensive hydrologic studies of the Arbuckle-Simpson aquifer were conducted between 2003 and 2011 to obtain the data and information necessary to perform groundwater-flow model simulations. The results of groundwater-flow simulations help to inform the OWRB’s decisions as they work to determine how much water could be withdrawn from the aquifer while maintaining flow to springs and streams (Seilheimer and Fisher, 2008; Christenson and others, 2009, 2011; Faith and others, 2010). Springs are outflows from the groundwater aquifers; changes in springflow over time across an aquifer could be an indicator of changes in aquifer water storage amounts. The OWRB established a maximum annual yield (MAY) in 2013 for the Arbuckle-Simpson aquifer based primarily on simulated effects of groundwater withdrawals on springflows and base flows into streams (OWRB, 2023). Maximum annual yield is a determination by the Board (OWRB) of the total amount of fresh groundwater that can be produced from each basin or subbasin allowing a minimum twenty (20) year life of such basin or subbasin (Oklahoma State Legislature, 2023b). The MAY was set for the entire extent of the Arbuckle-Simpson aquifer (not just for the eastern part of the Arbuckle-Simpson aquifer) to 78,404 acre-feet over the total land area of 392,019 acres, with the resulting equal-proportionate share determined to be 0.20 acre-foot per acre per year (OWRB, 2023). The equal-proportionate share is the maximum annual yield of water from a groundwater basin or subbasin which shall be allocated to each acre of land overlying such basin or subbasin (Oklahoma State Legislature, 2023b). Since completion of hydrologic studies between 2003 and 2011, the OWRB established rules for sensitive sole source aquifers (Oklahoma State Legislature, 2023c). In addition

to the general rules for the taking and use of groundwater in an aquifer with a determined maximum annual yield, the OWRB must also find that the proposed use of groundwater is not likely to degrade or interfere with springs or streams emanating in whole or in part from water originating from the sensitive-sole-source groundwater basin before it may approve the application and issue the appropriate permit. Well-spacing rules for sensitive sole source groundwater basins were established to help determine if taking and use of groundwater would interfere with springs or streams emanating from the aquifer. These rules are “(1) no new or proposed well shall be drilled and completed within 1,320 feet of a spring that flows 50 gallons per minute or more, emanates from the groundwater basin, and is identified in table 1–1 in appendix 1 (modified from Appendix D of Oklahoma State Legislature, 2023c); (2) no new or proposed well shall be drilled and completed within 2 miles of a spring that flows 500 gallons per minute or more, emanates from the groundwater basin and is identified in table 1–1 in appendix 1, unless the Board first determines that the total amount of groundwater authorized to be used from all wells within that radius is no more than 1,600 acre-feet per year; (3) no new or proposed well shall be drilled and completed within 1 mile of a stream segment considered to be perennial in the U.S. Geological Survey's (USGS’s) National Hydrography Dataset (USGS, 2023) and with a base flow of more than 500 gallons per minute that emanates from the groundwater basin” (Oklahoma State Legislature, 2023c). This report describes the results of a study done by the USGS, in cooperation with the OWRB and the Oka’ Institute, to document recently collected (2018–23) hydrologic data and assess water-budget changes for the area containing the eastern part of the Arbuckle-Simpson aquifer. The 2018–23 hydrologic data were collected as part of a Phase 2 study and were compared to hydrologic data collected during 2003–08 as part of a series of Phase 1 studies; data from Phase 1 are available in Christenson and others (2011). As part of the Phase 1 studies, an aquifer water budget was developed from a numerical model for the period 2003–08. The analysis of changes in the aquifer water budget from 2003–08 to 2018–23 could help resource managers better understand (1) changes in the overall balance of water in storage and potential effects on streamflow, (2) changes in groundwater levels, and (3) the effects of different water uses in the aquifer area on available water in both the eastern part of the Arbuckle-Simpson aquifer and streams overlying the eastern part of the Arbuckle-Simpson aquifer.

Study Area The largest groundwater withdrawals are from the eastern part of the Arbuckle-Simpson aquifer, which provides water to approximately 39,000 people in Ada and Sulphur, Oklahoma, and surrounding areas (OWRB, 2009). The eastern part of the Arbuckle-Simpson aquifer covers approximately 390 mi2 (249,600 acres) and is the largest

Introduction 3 of the three parts of the Arbuckle-Simpson aquifer by area and aquifer volume (Christenson and others, 2011). Each part of the Arbuckle-Simpson aquifer is associated with a different predominant structural geological feature: the Hunton Anticline (eastern part of the Arbuckle-Simpson aquifer), the Tishomingo Anticline (central part of the Arbuckle-Simpson aquifer), and the Arbuckle Anticline (western part of the Arbuckle-Simpson aquifer) (Christenson and others, 2011). The hydrologic study and groundwater-flow model in Christenson and others (2011) were focused on the eastern part of the Arbuckle-Simpson aquifer; the eastern part of the Arbuckle-Simpson aquifer is also the focus of this report. Christenson and others (2011, p. 14) noted that the eastern part of the Arbuckle-Simpson aquifer “is dominated by the Hunton anticline, but also includes other structural features, including the Belton and Clarita anticlines, the Sulphur syncline, and the Lawrence uplift.” Aquifer recharge refers to the process by which water enters a given aquifer and becomes part of the groundwater system (Freeze and Cherry, 1979). Direct recharge from precipitation is the primary source of groundwater in the Arbuckle-Simpson aquifer; little to no inflow of groundwater comes from surrounding aquifers. Groundwater discharge from the aquifer predominantly contributes to streams and springs, including Blue River, Pennington Creek, Mill Creek, and Delaware Creek, which originate as outflows from the aquifer, as well as numerous smaller streams (fig. 1). Groundwater discharge typically maintains base flow in streams overlying the aquifer (although this can change seasonally because of reductions of storage in the aquifer and reduced recharge to the aquifer during dry periods when there is less precipitation). Blue River, which drains a large extent of the eastern part of the Arbuckle-Simpson aquifer, is the largest stream that originates in the study area. Many springs, including Byrds Mill Spring, the primary water supply for the City of Ada, also discharge from the aquifer. During Phase 1, the discharge from Byrds Mill Spring was monitored by USGS streamgage 07334200 Byrds Mill Spring near Fittstown, Okla. (hereinafter referred to as the “Byrds Mill Spring gage” [table 1–1; fig. 2]).

Purpose and Scope The purpose of this report is to compare recent hydrologic data collected primarily during 2018–23 as part of a “Phase 2” study to historical hydrologic data collected primarily during 2003–08 and published in Christenson and others (2011) as part of an initial “Phase 1” study to determine how the water budget for the area overlying the eastern part of the Arbuckle-Simpson aquifer has changed. The analysis of changes in the aquifer water budget from 2003–08 to 2018–23 could help resource managers better understand changes in the overall balance of water in storage and potential effects to streamflow, changes in groundwater levels, and the effects of different water uses in the aquifer area on available water

in both the eastern part of the Arbuckle-Simpson aquifer and streams overlying the eastern part of the Arbuckle-Simpson aquifer. The organization and wording of this report is largely based on that of Christenson and others (2011).

Geology and Hydrogeologic Units The rocks that compose the Arbuckle-Simpson aquifer are exposed at the surface in an area of 520 mi2 of south-central Oklahoma, formally known as the Arbuckle Mountains. The topographic relief of these “mountains” is on the order of hundreds of feet, and their appearance is that of rolling hills to the west and an elevated plain to the east (Christenson and others, 2011). The Arbuckle Mountains are composed of Proterozoic- and Cambrian-aged igneous and metamorphic rocks overlain by sedimentary rocks that are Cambrian to Late Pennsylvanian in age (Christenson and others, 2011). The geology of the Arbuckle Mountains is characterized by both macro- and meso-scale deformations, consisting of folded structures, large fault displacements, uplifts, and karstic features developing in their carbonate sedimentary rocks (Fairchild and others, 1990). Sinkholes, caves, springs, and other characteristic karst features are present throughout the Arbuckle Mountains (Christenson and others, 2011). Because all these features affect the flow and availability of groundwater in the study area, the geologic framework of the Arbuckle Mountains is considered when assessing groundwater in the Arbuckle-Simpson aquifer.

Geologic History The geologic history of the Arbuckle Mountains encompasses more than a billion years, from Proterozoic igneous and metamorphic rocks to Quaternary alluvial deposits. There are four main phases of geologic history, including tectonics and sedimentation, that formed and shaped the Arbuckle Mountains of today: (1) an initial splitting apart of tectonic plates (rifting) during the Early and Middle Cambrian Epochs, (2) deposition and subsidence during the Late Cambrian Epoch through the Mississippian Subperiod, (3) uplift and deformation during the Pennsylvanian Subperiod, and (4) erosion and post-Pennsylvanian Subperiod tilting (Johnson, 1991). Before the first phase of rifting, during the Proterozoic Eon, the study area was underlain primarily by granites and gneisses. About 1.3 billion years ago, during the Proterozoic Eon, igneous dikes were intruded into the surrounding rock, which was the first evidence of crustal weakness that would later alter the geology of the area. In the Early and Middle Cambrian Epochs, the first phase of crustal deformation occurred, with rifting that caused the development of major normal faults along the margins and more igneous activity. As these igneous rocks cooled in the rift zone, the land surface began to subside, creating a trough that would subsequently be filled with sedimentary rocks.

4 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma 96°55'

GARVIN COUNTY

96°50'

96°45'

PONTOTOC COUNTY

Surficial extent of the western, central, and eastern parts of the Arbuckle-Simpson aquifer

34°45'

MURRAY COUNTY

Eastern

96°40'

96°35'

OKLAHOMA

Central

C re

Clear

07332307

Hickory

FITT

07331295

2.5

Cedar Creek

2.5

TISH

k ee

07331300

Creek

Rock

ATOKA COUNTY JOHNSTON COUNTY

ee Cr

Wapanucka S a

r Oil Creek Base from U.S. Geological Survey (USGS) digital data, various scales Albers Equal-Area Conic projection, standard parallels 0 29°30' and 45°30' N., central meridian 96°00' W. North American Datum of 1983 0

07334428

07332390

Keel Creek

Bromide

San

CARTER COUNTY

shita

ive

Reagan Branch

Blue River NEON Diamond Spring Branch ee Cr Peca n

Threemile Creek

07331205

Connerville

07331200

re Oil C

34°20'

t e r Sandy Creek

MURRAY COUNTY

Clarita

Creek

Mill Creek

Blue River 07332348

nd y

Mill C ree k

07331293

k re e ring C Sp on n Pen ni e e Cr

07331185

Little West Blue Creek S

aware Del

Cr ee k

07329852

34°25'

COAL COUNTY

Creek l ue Li t t l e B

34°30'

Sulphur Tr a v ertine

Tupelo Centrahoma

ek Cre

SULP

ra n och

y gg

34°35'

Stonewall

Cree k Fittstown nut Wal k Mi e e ll Cr 07332305

Limestone Creek

Roff

re e

Roc kC

dy an

PONTOTOC COUNTY d'Arc Cree is k Bo

JOHNSTON COUNTY

Cr eek

34°40'

96°25'

Area enlarged Map area showing showing the the surficial extent eastern part of the of the Arbuckle-Simpson Arbuckle-Simpson aquifer aquifer ADAX

Ahloso

Western

CARTER COUNTY

96°30'

HUGHES COUNTY

COAL COUNTY

97°00'

Coleman Surficial extent of the Arbuckle-Simpson aquifer from Oklahoma Water 10 MILES Resources Board (OWRB; 2024a)

7.5

10 KILOMETERS

EXPLANATION Surficial extent of the Arbuckle and Simpson Group rocks that contain the eastern part of the Arbuckle-Simpson aquifer

OWRB dedicated land for permitted well Public supply Mining Industrial (power) Irrigation Combined (recreation, fish, and wildlife; agriculture; and other) Unnamed upper confining unit deposited after the Simpson Group

Subwatershed boundary—12-digit hydrologic unit code (USGS Watershed Boundary Dataset) 07331200

Phase 1 USGS streamgage and USGS station number (USGS, 2024a)

07334428

Phase 2 USGS streamgage and USGS station number (USGS, 2024a)

TISH

Climate station and station identifier (ADAX, FITT, SULF, and TISH [Oklahoma Mesonet, 2023]; NEON [National Ecological Observatory Network, 2023])

OWRB permitted well by use type Public supply Mining Industrial Irrigation Combined recreation, fish, and wildlife; agriculture; and other OWRB surface-water diversion by use type Public supply Mining Industrial Irrigation Combined recreation, fish, and wildlife; agriculture; and other

Figure 1. Map of study area showing the eastern part of the Arbuckle-Simpson aquifer, U.S. Geological Survey streamgages where streamflow data were collected for the Phase 1 (2003–08) and Phase 2 (2018–23) studies, climate stations where precipitation data were collected, and surface-water diversions and permitted wells, south-central Oklahoma, 2003–23.

Introduction 5 97°00'

96°50' nadian S Ca an

Vanoss RC Longmire Lake

96°45'

96°40'

96°35'

96°30'

Ahloso ek Cre

OKLAHOMA

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Little

34°40'

reek yC

B l ue

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Uplif t Law rence

River

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Syn

cl i n

Connerville 342618096380101 342619096411001

342633096494401 Be l t on An t icl ine 342527096493301

342556096535601

reek yC

Keel Cre

Cedar C ree k

C re ek

ek y Cr e Sand Wapanucka

ran

Coleman

Base from U.S. Geological Survey (USGS) digital data, various scales Albers Equal-Area Conic projection, standard parallels 0 2.5 29°30' and 45°30' N., central meridian 96°00' W. North American Datum of 1983 0 2.5 5

5 7.5

Clarita ne t icli ta An

Bromide

342510096363901

342336096381201 07332389 ek 342155096412001

nB ga

re Oil C

Re a

Wa shi

k ree ll C Mi

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Diamond Spring Branch

Mill Creek

C lar i

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34°25' Lake of the Arbuckles

342921096381601

ee k ware C r D ela

hur

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Creek ing

342837096560801

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r S andy Creek

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07329849

Chickasaw National Recreation Area

H A n un t o t ic n lin 343058096484101 e

B g og

343240096523201 343017096561501

Sulphur

Centrahoma

Tupelo

Travertine Creek

34°20'

A is d' rc Creek Bo

e ek oc hra

34°35'

Area enlarged

Fitzhugh

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34°30'

96°25'

Ada

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34°45'

96°55'

Geology modified from Heran and others (2003) Surficial extent of the Arbuckle-Simpson 7.5 10 MILES aquifer from Oklahoma Water Resources Board (2024a) 10 KILOMETERS

EXPLANATION Individual geologic unit or geologic units grouped by age

Unnamed upper confining unit deposited after the Simpson Group

Cretaceous-age formation

Chickasaw National Recreation Area

Permian-Pennsylvanian-age formations Mississippian-Ordovician-age formations Ordovician-age Simpson Group Ordovician-Cambrian-age Arbuckle Group Cambrian-age Timbered Hills Group Proterozoic-age igneous and metamorphic rocks

Anticline Syncline

Fault Surficial extent of the Arbuckle and USGS spring gage** and USGS Simpson Group rocks that contain 07332389 station number (USGS, 2024a) the eastern part of Arbuckle-Simpson USGS groundwater monitoring aquifer 342510096363901 station (table 8) and USGS station number (USGS, 2024a) USGS station USGS station number

07329849 07332389 07334238 07334200*

name

Antelope Spring at Sulphur, Okla. Unnamed spring at Blue River near Connerville, Okla. Sheep Creek Spring near Fittstown, Okla. Byrds Mill Spring near Fittstown, Okla.

*Data from this spring gage were only used during Phase 1 analyses; gage was discontinued prior to Phase 2. **Discharge was continuously monitored at USGS streamgages at four major springs in the study area.

Figure 2. Geologic units exposed at the surface in the study area for the eastern part of the Arbuckle-Simpson aquifer, with locations of U.S. Geological Survey (USGS) groundwater monitoring stations where data were collected for the Phase 2 (2018–23) study and USGS spring gages where spring discharges were measured, south-central Oklahoma.

6 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma The Late Cambrian Epoch through the Mississippian Subperiod is marked by the second main phase of geologic history in the region. During this time, shallow seas covered much of the midcontinent of what is now North America, which caused deposition of carbonate sediments that would later become the Arbuckle Group that was deposited during the Late Cambrian Epoch through the Early Ordovician Epoch. Some of these sediments were deposited in the sedimentary trough, which is commonly referred to today as the Southern Oklahoma Aulacogen (Johnson and others, 1989; Chase and others, 2022). Sedimentary rocks that formed in the Southern Oklahoma Aulacogen are much thicker than the surrounding rock, with more than 17,000 feet (ft) of rock accumulation, relative to the surrounding continental shelf, which accumulated about 6,500 ft of rock during the same time period (Ham, 1973). At the end of the Early Ordovician Epoch the sea level decreased enough to expose these carbonate sediments to meteoric waters, resulting in the dolotomization of some rocks in the Arbuckle Group (Lynch and Al-Shaieb, 1991; Denison, 1997). Dolomitization is a process where the carbonate mineral dolomite is formed when magnesium ions replace calcium ions in calcite. This second phase of geologic history also saw the deposition of the Simpson Group of Middle to Late Ordovician age on top of the rocks of the Arbuckle Group. The Simpson Group is composed of marine-shelf carbonates, shales, and quartz sandstones, indicating a shallow-sea depositional environment (Johnson, 1991). The third phase of geologic history in the Arbuckle Mountains began in the Early Pennsylvanian Epoch and was marked by uplift and deformation, including the formation of the Hunton Anticline in the study area. The Late Pennsylvanian Epoch brought intense mountain building along the margins of the Southern Oklahoma Aulacogen, which resulted in tight folding and high angle thrust faulting of these rocks (Christenson and others, 2011). This mountain building event is thought to have been caused by a major plate collision between the North American plate and Gondwana or another smaller plate during the Late Pennsylvanian Epoch (Perry, 1989). Finally, the fourth phase of geologic history in the study area is characterized by additional deposition and erosion. After the Late Pennsylvanian Epoch mountain-building event, sediment deposits of Late Pennsylvanian age covered the Arbuckle Mountains. Red beds and evaporites of Permian age were deposited in basins, followed by shallow-sea sand and carbonate deposits of Cretaceous age (Johnson and others, 1989). These shallow seas also caused erosion of the Arbuckle Mountains, which were further flattened by fluvial erosion during the Cretaceous Period (Donovan, 1991). Further erosion and tilting in the study area was due to the uplift of the Rocky Mountains hundreds of miles west of the Arbuckle Mountains during the Laramide orogeny (English and Johnston, 2004). Alluvial and terrace sedimentation of Quaternary age deposited along streams and rivers round out this period of deposition and erosion in the study area

(Johnson and others, 1989). A more complete geologic history of the Arbuckle Mountains was detailed by Christenson and others (2011).

Structural Geology The geologic units that contain the eastern part of the Arbuckle-Simpson aquifer, which is the focus of this study, are shaped primarily by the Hunton Anticline, but include other structural features, including the Belton and Clarita Anticlines, the Sulphur Syncline, and the Lawrence Uplift (fig. 2). The Hunton Anticline is a broad anticlinal fold that exposed the Early Ordovician-age West Spring Creek and Kindblade Formations of the Arbuckle Group to the surface in the central part of the eastern part of the Arbuckle-Simpson aquifer (Johnson, 1990). The northwestern arm of the Hunton Anticline dips gently (less than 20 degrees; Christenson and others, 2011) westward, while the southeastern arm dips gently to the east. The Hunton Anticline is bounded by the Lawrence Uplift to the north, the Franks Fault Zone and the Clarita Fault to the northeast/east, and the Sulphur Fault Zone to the south (Christenson and others, 2011). The Sulphur Fault Zone consists of major northwest-southeast-trending faults, which were first displaced during the formation of basement rocks and were reactivated multiple times during Paleozoic Era rifting and orogeny (Harlton, 1966; Denison, 1995). The Sulphur Fault Zone roughly coincides with the northern edge of the Sulphur Syncline, which is bounded to the south by the South Sulphur Fault. Rocks from the Simpson Group were folded to form the Sulphur Syncline, which terminates to the southeast of the study area in the east and at approximately the Chickasaw National Recreation Area to the west (fig. 2). Results from a geophysical gravity study suggest that the Sulphur Syncline might be a graben rather than a syncline, but the name remains the same (Cates, 1989; Scheirer and Hosford Scheirer, 2006). South of the Sulphur Syncline lies the Belton Anticline, which makes up the southern portion of the eastern part of the Arbuckle-Simpson aquifer study area. The Belton Anticline is a northwest-plunging folded fault block that is structurally higher than the Hunton Anticline (Christenson and others, 2011). These structurally high areas have been eroded, which has exposed the Early Ordovician-age Cool Creek and McKenzie Hill Formations of the Arbuckle Group to the surface. The Mill Creek Fault marks the southern boundary of the eastern part of the Arbuckle-Simpson aquifer study area. This fault runs nearly parallel to the Sulphur Fault Zone, with a northwest-southeast trend, and is nearly vertical, based on gravity data collected near the Chickasaw National Recreation Area (Christenson and others, 2011). Several other small faults in a range of orientations mark the subsurface of the study area, further enhancing disjointed and preferential groundwater-flow paths (Fairchild and others, 1990; Riley, 2004; Scheirer and Hosford Scheirer, 2006; Sample, 2008; Kennedy and others, 2009; Halihan and others, 2009a; Smith and others, 2009; Young and others, 2009; Ramachandran and

Introduction 7 others, 2012). Detailed visualizations of the structural geology of the eastern part of the Arbuckle-Simpson aquifer area, including geologic unit outcroppings, major faults, structural features, and cross sections, can be found in figures 4, 6, and 7 of Christenson and others (2011).

Hydrogeologic Units The geologic units of the Arbuckle Mountains, which include the units that contain the Arbuckle-Simpson aquifer, are basement rocks (Cambrian rhyolites and Proterozoic granites and gneisses), the Timbered Hills Group of Late Cambrian age, the Arbuckle Group, and the Simpson Group. The basement rocks of the Arbuckle Mountains were formed in the Ectasian Period of the Mesoproterozoic Era and are the oldest rocks in the study area at 1.35 to 1.4 billion years old (Ham and others, 1964). They consist of igneous and metamorphic rocks and include the Tishomingo Granite, Troy Granite, and unnamed granodiorite and granitic gneiss. In the eastern part of the Arbuckle-Simpson aquifer study area, these basement rocks are only exposed at the surface as the core of the Belton Anticline in the southern part of the study area (Ham and others, 1964; Denison, 1973). These igneous and metamorphic rocks are cut by several Proterozoic- and Cambrian-age dikes and extrusive pyroclastic rocks. No high-yield water wells are completed in these igneous and metamorphic rocks because they are believed to have very low hydraulic conductivity due to their crystalline structure (Christenson and others, 2011). As a result, these basement rocks form a lower confining unit to the eastern part of the Arbuckle-Simpson aquifer with depths ranging from 3,100 to 4,600 ft below land surface (bls) (Campbell and Weber, 2006). The Arbuckle Group overlies the Timbered Hills Group and consists of Late Cambrian- to Early Ordovician-age carbonate rocks. The Arbuckle Group is approximately 3,000 ft thick in most of the eastern part of the Arbuckle-Simpson aquifer study area but has been eroded away over parts of the Belton Anticline (Christenson and others, 2011). The Arbuckle Group is divided into eight formations, which include the Fort Sill Limestone and Royer Dolomite of Late Cambrian age, the Signal Mountain Formation of Early Ordovocian age, and the Butterly Dolomite, McKenzie Hill Formation, Cool Creek Formation, Kindblade Formation, and West Spring Creek Formation of Early Ordovocian age, from oldest to youngest (fig. 3). Dolostones are the most common type of carbonate rock in the Arbuckle Group in the eastern part of the Arbuckle-Simpson aquifer (Ham, 1945). Numerous unconformities throughout the Arbuckle Group are evidence that the carbonate rocks were exposed to weathering, encouraging the development of karst features. Surface exposures of the Arbuckle Group, as well as cores of the subsurface, show examples of paleokarst features including dissolution in fractures and cavities, vuggy porosity, and collapse breccias. These paleokarst features increase the porosity of rocks in the Arbuckle Group, also increasing their permeability (Lynch and Al-Shaieb, 1991). The Arbuckle

Group is the larger (by both area and thickness) of the two lithostratigraphic groups that contain the Arbuckle-Simpson aquifer. The portion of the Arbuckle-Simpson aquifer contained in the Arbuckle Group is also more productive than the portion contained in the Simpson Group (Christenson and others, 2011) because of its intercrystalline porosity and because of the numerous fractures, solution channels, and cavities it contains (Fairchild and others, 1990). Wells completed in the portion of the Arbuckle-Simpson aquifer contained in the Arbuckle Group typically yield 200 to 500 gallons per minute (gal/min), with some deeper wells reported to yield up to 2,500 gal/min (Fairchild and others, 1990; Christenson and others, 2011). The Simpson Group is the younger of the lithostratigraphic groups contained in the Arbuckle-Simpson aquifer. The Simpson Group is generally less than 1,000 ft thick in the eastern part of the Arbuckle-Simpson aquifer and is exposed at the surface in about one-third of the total aquifer area (145 mi2; Christenson and others, 2011), typically along the edges of major anticlines and other structurally low areas. Erosion over the structurally higher locations in the aquifer has removed the Simpson Group from those areas (Ham, 1973). The largest outcrop of the Simpson Group in the eastern part of the Arbuckle-Simpson aquifer is on the eastern flank of the Hunton Anticline, with another exposure on the Sulphur Syncline. The Simpson Group was deposited during a time of sea level fluctuations, which resulted in the formation of porous quartzose sandstones interbedded with limestones, dolostones, and greenish-gray shales. The Simpson Group consists of five formations: the Joins, Oil Creek, and McLish Formations of Middle Ordovician age, and the Tulip Creek and Bromide Formations of Late Ordovician age (fig. 3). Because the Joins and Tulip Creek Formations are either very thin or absent in the eastern part of the Arbuckle-Simpson aquifer (Christenson and others, 2011), they will not be discussed further. The most well-developed formations in the eastern part of the Arbuckle-Simpson aquifer are the basal Oil Creek and McLish Formations, which have sandstones with thicknesses of up to 400 and 165 ft, respectively (Ham, 1945; Denison, 1997). These thick beds of uncemented quartz sandstones are mined locally to produce glass, and they store the majority of the water in the part of the eastern part of the Arbuckle-Simpson aquifer contained in the Simpson Group. Wells completed in the eastern part of the Arbuckle-Simpson aquifer contained in the Simpson Group typically yield 100 to 200 gal/min (Fairchild and others, 1990). Where the top of the eastern part of the Arbuckle-Simpson aquifer is not exposed at the surface, it is confined above by younger rocks of various ages deposited after the Simpson Group (fig. 3). This unnamed upper confining unit confines the eastern part of the Arbuckle-Simpson aquifer on the western edge of the Hunton Anticline, near Sulphur, Okla., and Chickasaw National Recreation Area. This unnamed upper confining unit consists

8 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Era Cenozoic

Period

Subperiod Quaternary

Epoch

Geologic unit

Hydrogeologic unit

Geologic units deposited after the Simpson Group1

Unnamed upper confining unit

Holocene

Late Mesozoic

Cretaceous Early Permian Pennsylvanian Carboniferous Mississippian

-Late Early --

Devonian

Silurian

-Tulip Creek Formation Bromide Formation

Late Middle

Simpson Group

McLish Formation Oil Creek Formation Joins Formation West Spring Creek Formation

Paleozoic

Kindblade Formation

Ordovician

Cool Creek Formation

Early

McKenzie Hill Formation

Arbuckle Group

Arbuckle-Simpson aquifer

Butterly Dolomite Signal Mountain Formation Royer Dolomite Fort Sill Limestone

Late Cambrian

Timbered Hills Group

Honey Creek Limestone Reagan Sandstone

Middle Early Neoproterozoic

Unnamed lower confining unit

Stenian --

Mesoproterozoic

Ectasian

Colbert Rhyolite

Tishomingo Granite, Troy Granite, granodiorite, and granitic gneiss

Includes Quaternary alluvial deposits

[--, Epoch not specified in National Geologic Map Database (U.S. Geological Survey, 2024b)]

Figure 3. Notable geologic and hydrogeologic units in the eastern part of the Arbuckle-Simpson aquifer. Modified from Christenson and others (2011).

Hydrologic Data Comparison: Phase 1 to Phase 2 9 primarily of conglomerate with some sandstone, shale, and minor nodular limestone and lies unconformably over the Arbuckle and Simpson Groups. Quaternary alluvial deposits are the youngest sediment deposits in the study area. These deposits, consisting of unconsolidated gravel, sand, silt, and clay, are primarily found along larger streams in the study area and are typically very thin and poorly defined. The nature of the Quaternary alluvial deposits is such that they likely would not have the properties of a confining unit; however, these deposits are also not expected to have appreciable hydrologic interaction with the eastern part of the Arbuckle-Simpson aquifer and were, therefore, included in the unnamed upper confining unit for simplicity.

Previous Hydrologic Studies and Phase 1 Study of the Arbuckle-Simpson Aquifer Hydrologic studies of the Arbuckle-Simpson aquifer were conducted between 2003 and 2011 documenting information that, in addition to characterizing the resources of the study area, helped the OWRB determine how much water could be withdrawn from the aquifer while maintaining flow to springs and streams. These previous hydrologic studies were completed by the USGS in cooperation with OWRB and by other entities working in collaboration with the USGS and OWRB, including the Bureau of Reclamation, Oklahoma State University, and University of Oklahoma (Vieux and Moreno, 2008; Christenson and others, 2009, 2011; Halihan and others, 2009a, b; Puckette, 2009; Puckette and others, 2009; Rahi and Halihan, 2009, 2012; Smith and others, 2009; Tarhule, 2009; Faith and others, 2010). In this report, Phase 1 refers to the study and data published in Christenson and others (2011); as mentioned in the Introduction section, Phase 1 data were primarily collected during 2003–08. The Christenson and others (2011) report includes an aquifer-wide Arbuckle-Simpson study, but the groundwater-flow model was developed for only the eastern part of the Arbuckle-Simpson aquifer (fig. 1). This series of studies is collectively known as the “Arbuckle-Simpson hydrology study.” The following are objectives of the Arbuckle-Simpson hydrology study. 1. Characterize the Arbuckle-Simpson aquifer in terms of geologic setting, aquifer boundaries, hydraulic properties, water levels, groundwater flow, recharge, discharge, and water budget. 2. Characterize the area’s surface hydrology, including stream and spring discharge, runoff, base flow, and the relation of surface water to groundwater. 3. Construct a digital groundwater/surface-water-flow model of the Arbuckle-Simpson aquifer system for use in evaluating the allocation of water rights and simulating management options.

4. Determine the chemical quality of the aquifer and principal streams, identify potential sources of natural contamination, and delineate areas of the aquifer that are most vulnerable to contamination. 5. Construct network stream models of the principal stream systems for use in the allocation of water rights. 6. Propose water management options, consistent with State water laws, that address water rights issues, the potential impacts of pumping on springs and stream base flows, water quality, and water-supply development.

Hydrologic Data Comparison: Phase 1 to Phase 2 Comparing hydrologic data from Phase 1 to data from Phase 2 will help resource managers better understand changes in streamflow, groundwater levels, and recharge to the aquifer. Different water uses in the aquifer area affect available groundwater storage and base flows in streams overlying the eastern part of the Arbuckle-Simpson aquifer. Although most of the data used in the Phase 1 were from 2003–08, additional data from years prior to 2003 were included in some of the analyses to inform the numerical model. Similarly, most of the data used in Phase 2 were from 2018–23, but additional data from prior years were included in some of the analyses to inform the conceptual water budget. In all instances where data from prior years were included, the nature of the data and the years when the data were collected are explained. The data used in this report are available in the companion USGS data release (Mashburn and others, 2025).

Climate The bulk of the eastern part of the Arbuckle-Simpson aquifer extends across four counties in southern Oklahoma: Coal, Johnston, Pontotoc, and Murray. These counties are in Oklahoma's south-central climate division, Climate Division 8. Climate Division 8 is characterized by the highest annual mean temperatures and the fourth highest annual mean precipitation values of the nine climate divisions in Oklahoma (Oklahoma Climatological Survey, 2023). Precipitation and temperature data for south-central Oklahoma were analyzed for the years 1895–2022 (fig. 4). Within this period, the minimum temperature recorded was 16.4 degrees Fahrenheit (°F) in February 1899, and the maximum recorded temperature was 104.7 °F in August 2011, with an overall increase in temperature of 0.04 °F per decade during the 1895–2022 period (National Centers for Environmental Information [NCEI], 2023). Annual cumulative precipitation values in south-central Oklahoma increased 0.41 inch per decade during the 1895–2022 period, with a maximum of 70.50 inches reported in 2015 and a minimum of 20.20 inches

10 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma reported in 1963 (NCEI, 2023). At the time when many of the analyses in this report were completed, precipitation data were only available through 2022. The mean annual precipitation for the 1895–2022 period was 37.97 inches per year (in/yr). Climate division data were also used to compare monthly variation in temperature and precipitation (fig. 5), including comparing mean monthly precipitation and temperature from the entire period of record to the periods of Phase 1 and Phase 2. All three periods of analysis follow similar monthly patterns, with temperature peaking in July–August and precipitation peaking in May–June. Mean monthly precipitation was greater in Phase 2 than in Phase 1

Annual precipitation, in inches

for the months of January, February, March, April, May, August, September, October, and December. Mean monthly temperatures were warmer in Phase 2 than in Phase 1 for the months of May, June, July, August, September, and December. In addition to information for Climate Division 8, data from several individual climate stations in and near the eastern part of the Arbuckle-Simpson aquifer were compiled to further categorize the climate of the region and relate to other data provided within the report. Annual precipitation values were summarized for the Mesonet stations in Ada, Fittstown, Sulphur, and Tishomingo, Okla. (fig. 1; table 1; Oklahoma Mesonet, 2023). Monthly precipitation data at Phase 1

Phase 2

20 Data from National Centers for Environmental Information (2023)

1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

Annual temperature, in degrees Fahrenheit (°F)

Phase 1

Phase 2

60 Data from National Centers for Environmental Information (2023)

1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

Year Note: Although Phase 2 extends from 2018 through 2023, precipitation and temperature data were only available through 2022 at the time this report was written.

EXPLANATION Period above or below 1895–2022 mean annual precipitation—Lighter shade indicates Phase 1 (2003–08) and Phase 2 (2018–23) study periods

Period above or below 1895–2022 mean annual temperature—Lighter shade indicates Phase 1 (2003–08) and Phase 2 (2018–23) study periods

Wet period

Warm period

Dry period

Cool period

Period when precipitation was above the mean annual precipitation

Period when temperature was above the mean annual temperature

Period when precipitation was below the mean annual precipitation

Period when temperature was below the mean annual temperature

Locally weighted scatterplot smoothing line (Cleveland, 1979) Annual mean precipitation Mean annual precipitation (37.97 inches per year) during 1895–2022 Annual mean temperature Mean annual temperature (62.0 °F) during 1895–2022

Figure 4. A, Annual mean precipitation with periods of above or below mean annual precipitation and B, annual mean temperature data with periods of above or below the mean annual temperature, south-central Oklahoma, 1895–2022.

Hydrologic Data Comparison: Phase 1 to Phase 2 11

A EXPLANATION Period of record (1895–2022)

Mean monthly precipitation, in inches per month

Phase 1 (2003–08) Phase 2 (2018–23)

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

Notes: Data from National Centers for Environmental Information (2023). Although Phase 2 extends from 2018 through 2023, precipitation data were only available through 2022 at the time this report was written.

Figure 5. A, Mean monthly precipitation and B, mean monthly temperature for south-central Oklahoma Climate Division 8 during 1895–2022, 2003–08, and 2018–22.

12 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Mean monthly temperature, in degrees Fahrenheit

80 70 60 50 40 30 20 10 0

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sept.

Oct.

Nov.

Dec.

EXPLANATION Period of record (1895–2022) Phase 1 (2003–08) Phase 2 (2018–23)

Figure 5.—Continued

the Blue River site, maintained by the National Science Foundation’s National Ecological Observatory Network (National Ecological Observatory Network [NEON], 2023), were summarized for September 2018–June 2022 (table 2).

Streamflow Monitoring Streamflow data were collected by using a collection of standardized USGS methods described in Sauer and Turnipseed (2010), Turnipseed and Sauer (2010), and Levesque and Oberg (2012). Sauer and Turnipseed (2010) describe the instrumentation and methods used for the acquisition of gage-height data. Turnipseed and Sauer (2010) describe the equipment and procedures used by the USGS for making streamflow measurements. Levesque and Oberg (2012) describe techniques for computing discharge records by using the index velocity method. Seven new USGS streamgages that monitor discharge were installed on streams flowing across the eastern part of the Arbuckle-Simpson aquifer as a part of Phase 2; in addition, five streamgages in the study area were used to monitor streamflow during Phase 1 and were still operational at the start of Phase 2 (table 3; fig. 1). Discharge readings

were recorded at the streamgages in either 15- or 30-minute intervals and transmitted to the USGS National Water Information System (NWIS) database (USGS, 2024a). The time-interval data were averaged at the end of each day and used to report daily mean discharge in cubic feet per second, and the data are all publicly available in NWIS. In streams that cross the surficial exposure of the rocks containing the eastern part of the Arbuckle-Simpson aquifer, streamflow tends to follow seasonal precipitation patterns. Streamflow is generally highest across all streams in the study area during the spring (March–May) when precipitation rates are higher and evapotranspiration rates are lower compared to the other seasons. Streamflow is lowest in the summer (June–August) and winter (December–February), likely because of lower precipitation rates compared to the spring (April–May) and fall (September–November), as well as higher evapotranspiration rates in the summer. These seasonal differences indicate that higher streamflows are dominated by runoff sources, whereas lower streamflows are dominated by base flow from groundwater sources (groundwater inflows to streams from the eastern part of the Arbuckle-Simpson aquifer).

Hydrologic Data Comparison: Phase 1 to Phase 2 13 Table 1. Annual precipitation at Mesonet climate stations and the mean precipitation recorded by those Mesonet stations each year (Oklahoma Mesonet, 2023), 1995–2022, south-central Oklahoma. [N/A, data not available]

Annual precipitation, in inches

Water year ADAX1

FITT2, 3

TISH4

SULP5

Mean, in inches

1995

38.60

N/A

48.64

46.68

44.64

1996

42.89

N/A

24.54

34.17

33.87

1997

35.79

N/A

29.20

36.08

33.69

1998

38.09

N/A

34.34

33.07

35.17

1999

46.31

N/A

37.62

45.61

43.18

2000

27.61

N/A

25.22

22.93

25.25

2001

43.55

N/A

52.79

48.01

48.12

2002

35.79

N/A

43.26

36.81

38.62

2003

29.77

N/A

30.41

33.74

31.31

2004

33.07

N/A

32.79

26.72

30.86

2005

44.40

21.05

36.89

45.78

37.03

2006

19.28

22.43

23.31

19.41

21.11

2007

53.32

51.18

44.32

51.36

50.05

2008

37.53

32.22

35.66

32.65

34.52

2009

38.24

42.53

38.77

37.53

39.27

2010

50.15

40.60

45.92

42.72

44.85

2011

17.38

18.88

20.37

20.47

19.28

2012

34.80

38.58

37.22

37.8

37.10

2013

33.40

32.93

30.76

27.33

31.11

2014

30.15

33.34

35.80

28.93

32.06

2015

65.74

61.62

66.95

62.40

64.18

2016

51.89

55.29

59.09

50.99

54.32

2017

39.49

47.39

43.42

47.65

44.49

2018

48.48

52.01

48.08

45.52

48.52

2019

43.14

48.12

58.92

48.67

49.71

2020

53.29

52.39

50.47

44.32

50.12

2021

38.95

38.22

35.38

35.92

37.12

2022

30.85

29.71

24.94

25.88

27.85

1Ada station (ADAX; fig. 1), Pontotoc County, Okla., latitude 34.798510 decimal degrees (dd), longitude −96.669090 dd. 2Fittstown station (FITT; fig. 1), Pontotoc County, Okla., latitude 34.552050 dd, longitude −96.717790 dd. 3Record incomplete for Fittstown station (FITT) in 2005. 4Tishomingo station (TISH; fig. 1), Johnston County, Okla., latitude 34.332620 dd, longitude −96.678950 dd. 5Sulphur station (SULP; fig. 1), Murray County, Okla., latitude 34.566100 dd, longitude −96.950480 dd.

14 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 2. Monthly precipitation recorded by the Blue River NEON station (National Ecological Observatory Network [NEON], 2023), September 2018–June 2022, Johnston County, Oklahoma. [N/A, data not available; dd, decimal degrees]

Month and year

Precipitation recorded by NEON Blue River1 station, in inches

Month and year

Precipitation recorded by NEON Blue River1 station, in inches

September 2018

1.19

August 2020

N/A

October 2018

2.92

September 2020

N/A

November 2018

0.16

October 2020

N/A

December 2018

2.54

November 2020

N/A

January 2019

1.49

December 2020

N/A

February 2019

0.73

January 2021

N/A

March 2019

0.72

February 2021

N/A

April 2019

0.94

March 2021

1.03

May 2019

3.33

April 2021

3.33

June 2019

1.66

May 2021

3.53

July 2019

0.99

June 2021

1.05

August 2019

2.60

July 2021

1.29

September 2019

1.32

August 2021

2.08

October 2019

2.29

September 2021

0.95

November 2019

1.54

October 2021

1.89

December 2019

0.64

November 2021

0.82

January 2020

1.15

December 2021

0.70

February 2020

0.80

January 2022

0.30

March 2020

0.97

February 2022

0.88

April 2020

0.24

March 2022

1.19

May 2020

0.62

April 2022

1.45

June 2020

N/A

May 2022

2.45

July 2020

N/A

June 2022

1.65

1NEON Blue River station (fig. 1), Johnston County, Okla., 34.444218 decimal degrees (dd), −96.624201 dd.

Hydrologic Data Comparison: Phase 1 to Phase 2 15 Table 3. Periods of record for U.S. Geological Survey streamgages in and near the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma. [USGS, U.S. Geological Survey; OK, Oklahoma; Cr, Creek; 3Mile, Threemile; Blw, below; Del, Delaware; RSVR, reservoir; nr, near. Data are from USGS (2024a). Dates are in year-month-day format. Phase 1 refers to the 2003–08 data collection period; Phase 2 refers to the 2018–23 data collection period]

USGS station number

Latitude, in decimal degrees

USGS station name

Longitude, in decimal degrees

Period of record

Streamgages used for monitoring during Phases 1 and 2 07329852

Rock Creek at Sulphur, OK

34.49536695

−96.9886281

1989-10-01 to currently operating (2024)1

07331200

Mill Creek near Mill Creek, OK

34.40509165

−96.8633439

2006-09-07 to currently operating (2024)1

07331295

Pennington Creek East of Mill Creek, OK

34.42036998

−96.7588959

2006-09-09 to currently operating (2024)1

07331300

Pennington Creek near Reagan, OK

34.3513333

−96.7103889

2003-10-01 to currently operating (2024)1

07332390

Blue River near Connerville, OK

34.45441944

−96.6356389

1976-10-01 to currently operating (2024)1

07331185

Mill Creek near Sulphur, OK

34.4773361

−96.9057806

2019-10-17 to currently operating (2024)1

07331205

Mill Cr at Mouth of 3Mile Cr near Mill Cr, OK2

34.3888361

−96.8457611

2019-09-05 to currently operating (2024)1

07331293

Pennington Creek North of Mill Creek, OK

34.47745278

−96.8113167

2018-10-24 to currently operating (2024)1

07332305

Blue River West of Fittstown, OK

34.5931452

−96.7061198

2019-12-21 to 2023-12-10

07332307

Blue River near Franks, OK

34.5781455

−96.6988971

2019-07-26 to currently operating (2024)1

07332348

Blue River North of Connerville, OK

34.383426

−96.6005579

2019-08-08 to currently operating (2024)1

07334428

Delaware Cr Blw Del Cr Site 9 RSVR nr Bromide, OK

34.40701667

−96.5399306

2019-09-05 to currently operating (2024)1

Streamgages used for monitoring during Phase 2

1Operating as of the time of publication of this report in 2024. 2Threemile Creek is the official name for 3Mile Creek (U.S. Board on Geographic Names, 2024).

Other streamgages in the study area include USGS streamgage 07329849 for groundwater sites using township, range, and section information: 01S, Township 01 South; 03E, Range 03 East; 01, Section 01; ABB, Northeast quarter of the Northwest quarter of the Northwest quarter of the section; 1, number designating that this is the first site in the NWIS database with this location information Antelope Spring at Sulphur, Okla. (hereinafter referred to as the “Antelope Spring gage”), USGS streamgage 07332389 unnamed spring at Blue River near Connerville, Okla. (hereinafter referred to as the “unnamed Blue River spring gage”), and USGS streamgage 07334238 Sheep Creek Spring near Fittstown, Okla. (hereinafter referred to as the “Sheep Creek Spring gage”) (fig. 2). The median daily flow at the Antelope Spring gage, USGS streamgage 07329852 Rock Creek at Sulphur, Okla., USGS streamgage 07331200 Mill Creek near Mill Creek, Okla., and USGS streamgage 07331300 Pennington Creek near Reagan, Okla. (hereinafter referred to as “Pennington Creek near Reagan gage”) decreased by 21.9 to 37 percent between Phases 1 and 2. Median daily streamflow at the USGS streamgage 07332390 Blue River near Connerville,

Okla. (hereinafter referred to as the “Blue River streamgage”) increased between Phases 1 and 2. The Byrds Mill Spring gage was discontinued prior to Phase 2. Maximum daily streamflow values increased at most sites that were monitored as a part of the Phase 1 studies, whereas minimum daily streamflow values decreased at every site that was monitored in both Phase 1 (table 4) and Phase 2 (table 5) studies. Compared to smaller precipitation events, the largest (maximum) precipitation events generated more runoff and less recharge to the aquifer during both phases. The reduced minimums in streamflow during Phase 2 are indicative of less recharge and longer dry periods between large precipitation events. Overall, a larger range of streamflow values was observed in Phase 2 than in Phase 1. Water levels in the aquifer were affected by drought conditions, which lasted from 2011 to 2015, followed by a period of heavy precipitation and flooding in 2015 (2015 was the wettest year during the 1895–2011 period; fig. 4A). These climate conditions affected the maximum and minimum discharge values observed in Phase 2 as compared to those of Phase 1.

[USGS, U.S. Geological Survey; ft3/s, cubic foot per second. Data are from USGS (2024a). Dates are in year-month-day format]

USGS station number

USGS station name

Phase 1 period analyzed

Mean daily flow (ft3/s)

Minimum daily flow (ft3/s)

25th percentile daily flow (ft3/s)

Median daily flow (ft3/s)

75th percentile daily flow (ft3/s)

Maximum daily flow (ft3/s)

07329849

Antelope Spring at Sulphur, Okla.

1985-11-20 to 1989-09-30; 2002-10-01 to 2008-09-30

2.74

1.1

2.7

4.0

07329852

Rock Creek at Sulphur

1989-10-01 to 2008-09-30

54.0

1.4

9.0

3,450

07331200

Mill Creek near Mill Creek

2006-09-07 to 2008-09-30

28.3

0.14

3.8

7.5

1,490

07331295

Pennington Creek east of Mill Creek

2006-09-09 to 2008-09-30

23.8

3.8

6.2

930

07331300

Pennington Creek near Reagan

2003-10-01 to 2008-09-30

43.0

9.9

2,560

07332390

Blue River near Connerville

1976-10-01 to 1979-09-30; 2003-10-01 to 2008-09-30

82.7

6,330

07334200

Byrds Mill Spring near Fittstown (combined flow)

1989-12-20 to 2008-09-30

18.5

4.6

16 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Table 4. Summary statistics for streamgages used during Phase 1 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.

Table 5. Changes in daily streamflow between Phase 1 and Phase 2 for the eastern part of the Arbuckle-Simpson aquifer, Oklahoma. [USGS, U.S. Geological Survey; ft3/s, cubic foot per second. Data are from USGS (2024a). Dates are in year-month-day format; N/A, not applicable]

Percent change in mean flow between Phases 1 and 2

Percent change in minimum flow between Phases 1 and 2

Percent change in 25th percentile flow between Phases 1 and 2

Percent change in median flow between Phases 1 and 2

Percent change in 75th percentile flow between Phases 1 and 2

Percent change in maximum flow between Phases 1 and 2

1985-11-20 to 1989-09-30; 2002-10-01 to 2008-09-30

−20.7

N/A

−34.5

−28.0

−24.6

−33.2

Rock Creek at Sulphur

1989-10-01 to 2008-09-30

−43.0

+9.6

−33.5

−37.0

−16.4

−52.2

07331200

Mill Creek near Mill Creek

2006-09-07 to 2008-09-30

−38.9

−100.0

−49.0

−31.2

−5.5

−56.9

07331295

Pennington Creek east of Mill Creek

2006-09-09 to 2008-09-30

−12.8

−92.4

−54.2

−32.0

+62.5

−57.3

07331300

Pennington Creek near Reagan

2003-09-09 to 2008-09-30

+0.3

−84.5

−55.0

−21.9

+45.5

−53.8

07332390

Blue River near Connerville

1976-10-01 to 1979-09-30; 2003-10-01 to 2008-09-30

+62.3

−18.3

+5.8

+33.0

+137.8

−35.0

USGS station number

USGS station name

Phase 2 period analyzed

07329849

Antelope Spring at Sulphur

07329852

Hydrologic Data Comparison: Phase 1 to Phase 2 17

18 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Base Flow Base-flow separation is the method of separating the base-flow or groundwater component from the runoff component to determine the percentage of each that compose the total streamflow. Base-flow separation methods are based on the assumptions that water discharging an aquifer to a stream is continuous. Over time, changes in the ratio of base flow to total streamflow may indicate changes in groundwater storage or availability. Base-flow separation was completed by using the PART program of the USGS Groundwater Toolbox (Barlow and others, 2015). The PART method uses streamflow partitioning to estimate daily base flow from the streamflow record and is based on the antecedent streamflow recession (Rutledge, 1998; fig. 6). The PART method is used for the analysis of the groundwater-flow system of a basin for which a streamflow-gaging station at the downstream end can be considered the only point of outflow. One assumption of the PART method is that the area of the contributing groundwater-flow system is equal to the drainage area of the streamflow-gaging station for the purpose of expressing flow in units of specific discharge (length per time). To use the PART method, regulation and diversion of flow should be negligible and the drainage-basin area should be less than 500 mi2 (Rutledge, 1998). For this report, negligible regulation for a streamflow-gaging station is defined as having less than 20 percent of the drainage area upstream from a streamflow-gaging station controlled by dams, floodwater-retarding structures, or other human modifications of streamflow. Analysis of hydrographs using PART results in periods of time (annual, monthly, seasonal) with base-flow and runoff portions of streamflow for which base-flow percentages can be calculated. Base-flow separation during Phase 1 and Phase 2 was done by using the PART hydrograph-separation method included in the USGS Groundwater Toolbox (Barlow and others, 2015). For the PART hydrograph-separation computations, the subsurface watershed areas used were from table 8, page 39, in Christenson and others (2011). Base-flow separation was completed for the Phase 1 studies for calendar years 2004–08 for the streamflow records collected at the Blue River streamgage and Pennington Creek near Reagan gage, and for calendar years 2007–08 for the streamflow records collected at USGS streamgage 07331200 Mill Creek near Mill Creek, Okla. (hereinafter referred to as

the "Mill Creek near Mill Creek gage"). Mean annual base flow was 74.2 percent of the total streamflow measured at the Blue River streamgage (fig. 6). Mean annual base flow computed at the Pennington Creek near Reagan gage was 82.8 percent of the total streamflow measured in Pennington Creek. Mean annual base flow computed at the Mill Creek near Mill Creek gage was 52.5 percent of the total streamflow measured in Mill Creek. The streamflow measured at the Byrds Mill Spring gage was 100 percent base flow because it consisted entirely of groundwater issuing from Byrds Mill Spring with no surface-water component. During 1990–2005, streamflow at the Byrds Mill Spring gage averaged 18.5 cubic feet per second (ft3/s). Base-flow separation was completed for Phase 2 for calendar years 2018–22 at the Blue River streamgage, the Pennington Creek near Reagan gage, and the Mill Creek near Mill Creek gage. Mean annual base flow at the Blue River streamgage was 70.3 percent of the total streamflow (fig. 6). Mean annual base flow at the Pennington Creek near Reagan gage was 79.7 percent of the total streamflow. Mean annual base flow at the Mill Creek near Mill Creek gage was 61.1 percent of the total streamflow. Base flow increased from Phase 1 to Phase 2 at all three streamgages. However, the base-flow portion of streamflow decreased from Phase 1 to Phase 2 at two of the three streamgages analyzed (fig. 6). One issue with attempting to compute the base-flow portion of streamflow is the influence of anthropogenic discharges upstream, such as stream augmentation from producing mines (described in the “Consumptive Water Use at Producing Mines” section of this report). These discharges affect streamflows measured and analyses of streamflows for interpretation of groundwater and surface-water interactions and base-flow analyses (fig. 7). The increases in the base-flow portion of streamflow and total streamflow during Phase 2 (fig. 6C) could be related to these upstream discharges.

Net Streamflow Gains and Losses Net gains and losses in streamflow along stream segments can be quantified by using discrete discharge measurements made during base-flow conditions, commonly referred to as synoptic base-flow (seepage-run) measurements. Locations of these measurements can be mapped to illustrate interactions with the underlying aquifer during base-flow conditions.

Hydrologic Data Comparison: Phase 1 to Phase 2 19

200 180 160 140 120

A. USGS streamgage 07331300 Pennington Creek near Reagan, OK (table 3) Phase 1

Phase 2

(During Phase 1, the percentage of total flow represented by base flow was 82.3%.)

(During Phase 2, the percentage of total flow represented by base flow was 79.7%.)

100 80 60 40 20 0

Flow, in cubic feet per second

450 400 350 300 250 200

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

B. USGS streamgage 07332390 Blue River near Connerville, OK (table 3) Phase 1 (During Phase 1, the percentage of total flow represented by base flow was 74.2%.)

Phase 2 (During Phase 2, the percentage of total flow represented by base flow was 70.3%.)

150 100 50 0

200 180

2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022

C. USGS streamgage 07331200 Mill Creek near Mill Creek, OK (table 3) Phase 1

Phase 2 (During Phase 1, the percentage of total flow represented by base flow was 52.5%.)

160 140 120 100 80 60

(During Phase 2, the percentage of total flow represented by base flow was 61.1%.)

40 20 0

2007

2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021

2022

Calendar year EXPLANATION Base flow Runoff

Figure 6. Annual mean base-flow estimates and mean annual base-flow for selected streams crossing the eastern part of the Arbuckle-Simpson aquifer Phase 1 (2003–08) to Phase 2 (2018–23), south-central Oklahoma.

Log10 streamflow, in cubic feet per second (ft3/s)

USGS streamgage 07331200 Mill Creek near Mill Creek, OK

100.00

10.00

1.00

0.10

Possible period of streamflow augmentation

0.01 3/31/2023

5/1/2023

5/31/2023

7/1/2023

7/31/2023

8/31/2023

9/30/2023

10/31/2023

11/30/2023

12/31/2023

1/30/2024

3/1/2024

3/31/2024

EXPLANATION 07331200 Mill Creek near Mill Creek, OK 50-percent exceedance for calendar year 2023 (4.51 ft3/s) 50-percent exceedance for calendar year 2024 (4.3 ft3/s)

Figure 7. Streamflow before, during, and after augmentation from producing-mine discharges upstream from U.S. Geological Survey streamgage 07331200 Mill Creek near Mill Creek, Oklahoma, March 2023–April 2024.

20 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

1,000.00

Hydrologic Data Comparison: Phase 1 to Phase 2 21 Discharge was measured at 40 stream locations at USGS stations, including several USGS streamgages, across the land surface overlying the aquifer in each stream main stem and selected tributaries (table 6; figs. 8–9). The relative net gain or loss of groundwater from or to the aquifer for each stream segment between two measurements was calculated (figs. 8–9). To ensure base-flow conditions were being captured, with as little runoff as possible, streamflow discharge was measured during January 24–31, 2022 (fig. 8), and February 28–March 1, 2023 (fig. 9), when evapotranspiration and groundwater withdrawals were considered minimal and after runoff from any precipitation events had dissipated (streamflow hydrographs in and near the study area were analyzed to ensure runoff had dissipated). Fewer sites were measured in 2023 due to lack of access to sites. Discrete discharge measurements, referred to as synoptic base-flow measurements (seepage runs), were made at several sites along streams during a period of relatively low precipitation in a short period of time to determine base flow. Synoptic base-flow measurements were collected by using the methods of Rantz and others (1982) and Turnipseed and Sauer (2010). Each streamflow measurement was assigned a quality rating by the field technician. The following ratings were assigned to measurements based on USGS guidelines (Turnipseed and Sauer, 2010): excellent, measured discharge was within 2 percent of actual discharge; good, measured discharge was within 5 percent of the actual discharge; fair, measured discharge was within 10 percent of the actual discharge; poor and unspecified, measured discharge was assumed to be within 8 percent of actual discharge (table 6). Gaining and losing segments were determined by calculating the difference in seepage (streamflow discharge) measurements at each end of a segment. To calculate a rate of gain or loss per mile along the segment, the difference in discharge was divided by the stream length between the upstream and downstream measurement. Base flow increases in the downstream direction in a gaining stream as water seeps into the stream from the aquifer, whereas base flow decreases in the downstream direction in a losing stream as water seeps out of the stream to the aquifer (Winter and others, 1998). Tributary inflow was accounted for in these measurements by subtracting tributary discharge from the upstream measurement. The 2022 seepage measurements indicated net gaining stream reaches along portions of Rock Creek, Mill Creek, Pennington Creek, and the Blue River (fig. 8). Net gaining stream reaches indicate that groundwater from the Arbuckle-Simpson aquifer is flowing into streambeds and maintaining streamflows. Upstream reaches of the Blue River to the north of site AM-18 were net losing; streamflows ranged from 0.00 to 4.28 ft3/s in these reaches, indicating net seepage losses from the stream into the Arbuckle-Simpson aquifer. Streamflows measured between sites AM-18 and AM-19 indicated a gain of 2.33 ft3/s per mile. Streamflow measured at the Blue River streamgage (site AG-12) and the

measurement upstream at site AM-25 indicated a gain of 7.63 ft3/s per mile. There was no flow in the upper reach of Pennington Creek upstream from site AG-06 or between the next two downstream seepage measurement sites AM-11 and AM-12. There was no flow in Mill Creek upstream from sites AM-07 and AG-03, but there was streamflow between sites AG-03 and AG-04, and in this reach streamflow increased by 0.27–0.28 ft3/s per mile. Delaware Creek lost streamflow between sites AM-26 and AG-13. Little Blue Creek, a tributary to the Blue River, gained streamflow of 0.26 ft3/s per mile between sites AM-21 and AM-20. The 2023 seepage measurements indicated that more stream segments were gaining than during the 2022 seepage measurements on Mill Creek, Pennington Creek, Blue River, Little Blue Creek, and Delaware Creek (fig. 9). In addition, streamflows computed at USGS streamgages in the study area were generally greater during February 28–March 1, 2023, than during January 24–31, 2022. For example, streamflow values at sites AG-09 and AG-10 during 2022 were both 0.0 ft3/s, but streamflow values during 2023 at those streamgages were 12.7 and 11.5 ft3/s, respectively.

Springflow Monitoring Springs are a common feature of karst aquifers, and numerous springs issue from the eastern part of the Arbuckle-Simpson aquifer (OWRB, 2003). Spring discharge measurements were collected by using the same methods as described for the streamflows in the “Streamflow Monitoring” section of this report. Springs are points or areas of natural outflow of groundwater to the land surface. Where this groundwater discharges from the Arbuckle-Simpson aquifer, groundwater can discharge downstream to join a stream, can re-enter the aquifer if karstification continues downgradient, or can be naturally dammed to create a pond, such as the pond that was formed in the 1870s by damming Byrds Mill Spring, which was later enclosed in 1927 in a cement and metal structure (OWRB, 2007). In addition, when groundwater discharges to the land surface, especially if it flows into a pond that is not enclosed, some of that water will be lost to evaporation.

Continuous Springflow Monitoring Discharge was continuously monitored at USGS streamgages at four major springs in the study area: Antelope Spring, unnamed Blue River spring, Byrds Mill Spring, and Sheep Creek Spring (fig. 2). Byrds Mill Spring near Fittstown, Okla. (07334200; table 1–1 in appendix 1) was monitored during 1959–2017 at the Byrds Mill Spring gage; data were used in the Phase 1 analyses, but this gage was discontinued prior to the initiation of the Phase 2. Seasonal patterns were observed in spring discharge. Spring discharge was generally lower in summer and winter when there is typically less precipitation compared to fall

22 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 6. Discrete discharge measurements made as part of the 2022 and 2023 seepage runs in and near the study area for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma. [USGS, U.S. Geological Survey; ft3/s, cubic foot per second; blw, below; OK, Oklahoma; nr, near; N, north; E, east; W, west; Rd, road; 3Mile, Threemile; abv, above; Cr, Creek; Rvr, River; CCDC, southwest quarter of the southeast quarter of the southwest quarter of the southwest quarter; Br, branch; RSVR, reservoir; Br, branch; RSVR, reservoir. Dates are in month/day/year format. Times are in hour:minute:second format. Data are from USGS (2024a). Measurement ratings: excellent, within 2 percent of the actual flow; good, within 5 percent; fair, within 8 percent; and poor, differs from the actual flow by more than 8 percent (Turnipseed and Sauer, 2010)]

Map identifier (figs. 8, 9)

USGS station number

USGS station name

Measurement date

Measurement time

Discharge, in ft3/s

Measurement rating

Type of streamgage1

2022 AM-01

073294514

Rock Creek blw Travertine Creek at Sulphur, OK

1/25/2022

12:52:00

5.76

Good

Synoptic

AM-02

073298393

Rock Creek nr Sulphur, OK

1/25/2022

10:36:30

0.04

Poor

Synoptic

AM-03

073298394

Hogskin Creek nr Sulphur, OK

1/25/2022

10:10:42

0.01

Poor

Synoptic

AM-04

073298395

Rock Creek at W. Palmer Rd nr Sulphur, OK

1/24/2022

16:30:36

0.26

Poor

Synoptic

AM-05

073298396

Cochran Creek nr Sulphur, OK

1/24/2022

15:51:12

0.02

Poor

Synoptic

AM-06

07329840

Rock Creek below Cunningham Well, 01N-03E-23 CCDC

1/24/2022

09:52:22

0.71

Poor

Synoptic

AG-01

073298507

Travertine Creek above U.S. 177 at Sulphur

1/24/2022

11:37:25

3.17

Poor

Continuous

AG-02

07329852

Rock Creek at Sulphur, OK

1/24/2022

14:35:50

5.91

Fair

Continuous

AM-07

7331183

Mill Creek at Hwy 7 nr Sulphur, OK

1/24/2022

09:35:12

Excellent

Synoptic

AG-03

07331185

Mill Creek near Sulphur, OK

1/24/2022

10:10:30

Excellent

Continuous

AM-08

07331188

Mill Creek NW of Mill Creek, OK

1/25/2022

12:52:59

1.41

Poor

Synoptic

AG-04

07331200

Mill Creek near Mill Creek, OK

1/24/2022

12:04:14

2.42

Fair

Continuous

AG-05

07331205

Mill Cr at Mouth of 3Mile Cr near Mill Cr, OK

1/24/2022

15:59:33

1.78

Poor

Continuous

AM-09

07331212

Threemile Creek near Mill Creek, OK

1/24/2022

13:15:03

0.12

Poor

Synoptic

AM-10

07331214

Threemile Ck at Jewel 1/24/2022 Sikes Rd nr Mill Creek, OK

14:52:59

0.11

Poor

Synoptic

AG-06

07331293

Pennington Creek North of Mill Creek, OK

1/24/2022

09:58:30

Unspecified

Continuous

AM-11

073312935

Pennington Creek at Stinson Rd nr Mill Creek, OK

1/24/2022

10:59:30

Unspecified

Synoptic

Hydrologic Data Comparison: Phase 1 to Phase 2 23 Table 6. Discrete discharge measurements made as part of the 2022 and 2023 seepage runs in and near the study area for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.—Continued [USGS, U.S. Geological Survey; ft3/s, cubic foot per second; blw, below; OK, Oklahoma; nr, near; N, north; E, east; W, west; Rd, road; 3Mile, Threemile; abv, above; Cr, Creek; Rvr, River; CCDC, southwest quarter of the southeast quarter of the southwest quarter of the southwest quarter; Br, branch; RSVR, reservoir; Br, branch; RSVR, reservoir. Dates are in month/day/year format. Times are in hour:minute:second format. Data are from USGS (2024a). Measurement ratings: excellent, within 2 percent of the actual flow; good, within 5 percent; fair, within 8 percent; and poor, differs from the actual flow by more than 8 percent (Turnipseed and Sauer, 2010)]

Map identifier (figs. 8, 9)

USGS station number

USGS station name

Measurement date

Measurement time

Discharge, in ft3/s

Measurement rating

Type of streamgage1

2022—Continued AM-12

07331294

Pennington Creek nr Mill Creek, OK

1/24/2022

11:30:30

Unspecified

Synoptic

AG-07

07331295

Pennington Creek East of Mill Creek, OK

1/24/2022

13:04:50

1.38

Poor

Continuous

AM-13

073312975

Spring Creek near Mill Creek, OK

1/24/2022

16:47:26

Unspecified

Synoptic

AG-08

07331300

Pennington Creek near Reagan, OK

1/24/2022

15:38:10

3.77

Poor

Continuous

AM-14

07331310

Keel Creek near Reagan, Ok

1/24/2022

16:05:48

Unspecified

Synoptic

AM-15

07332295

Blue River abv Limestone Creek nr Roff, OK

1/24/2022

10:30:57

4.28

Fair

Synoptic

AM-16

07332297

Limestone Creek near Roff, OK

1/24/2022

11:09:30

Excellent

Synoptic

AM-17

07332302

Blue River near Roff, OK

1/24/2022

12:14:06

3.04

Fair

Synoptic

AG-09

07332305

Blue River West of Fittstown, OK

1/24/2022

13:38:00

Excellent

Continuous

AG-10

07332307

Blue River near Franks, OK

1/24/2022

13:59:00

Excellent

Continuous

AM-18

07332310

Blue River near Fittstown, OK

1/24/2022

14:16:30

Excellent

Synoptic

AM-27

07332315

Little West Blue Creek nr Sulpher,2 OK

1/25/2022

10:13:30

Excellent

Synoptic

AM-19

07332346

Blue Rvr blw little W. Blue Ck nr Connerville, OK

1/25/2022

14:09:08

22.0

Unspecified

Synoptic

AG-11

07332348

Blue River North of Connerville, OK

1/25/2022

13:15:15

20.6

Fair

Continuous

AM-20

07332350

Blue River at Connerville, OK

1/25/2022

12:44:11

29.9

Fair

Synoptic

AM-21

07332355

Little Blue Creek nr Fittstown, OK

1/24/2022

14:39:00

Excellent

Synoptic

AM-22

07332358

Little Blue Creek at Hwy 377 at Pontoc, OK

1/24/2022

15:26:50

0.75

Fair

Synoptic

AM-23

07332360

Little Blue Creek nr Connerville, OK

1/25/2022

13:54:20

1.76

Poor

Synoptic

24 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 6. Discrete discharge measurements made as part of the 2022 and 2023 seepage runs in and near the study area for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.—Continued [USGS, U.S. Geological Survey; ft3/s, cubic foot per second; blw, below; OK, Oklahoma; nr, near; N, north; E, east; W, west; Rd, road; 3Mile, Threemile; abv, above; Cr, Creek; Rvr, River; CCDC, southwest quarter of the southeast quarter of the southwest quarter of the southwest quarter; Br, branch; RSVR, reservoir; Br, branch; RSVR, reservoir. Dates are in month/day/year format. Times are in hour:minute:second format. Data are from USGS (2024a). Measurement ratings: excellent, within 2 percent of the actual flow; good, within 5 percent; fair, within 8 percent; and poor, differs from the actual flow by more than 8 percent (Turnipseed and Sauer, 2010)]

Map identifier (figs. 8, 9)

USGS station number

USGS station name

Measurement date

Measurement time

Discharge, in ft3/s

Measurement rating

Type of streamgage1

2022—Continued AM-24

07332370

Blue River near Bromide, OK

1/25/2022

11:00:49

30.2

Good

Synoptic

AM-25

07332380

Blue River ab 1/24/2022 Diamond Spring Br nr Connerville, OK3

15:09:43

30.7

Fair

Synoptic

AG-12

07332390

Blue River near Connerville, OK

1/24/2022

12:55:48

43.6

Poor

Continuous

AM-26

07334426

Delaware Creek nr Connerville, OK

1/25/2022

11:00:49

30.2

Good

Synoptic

AG-13

07334428

Delaware Cr Blw Del Cr Site 9 RSVR nr Bromide, OK

1/31/2022

15:51:32

0.86

Poor

Continuous

AM-01

073294514

Rock Creek blw Travertine Creek at Sulphur, OK

3/1/2023

11:09:18

24.1

Fair

Synoptic

AM-02

073298393

Rock Creek nr Sulphur, OK

2/28/2023

11:25:21

4.02

Fair

Synoptic

AM-03

073298394

Hogskin Creek nr Sulphur, OK

2/28/2023

10:51:06

0.34

Poor

Synoptic

AM-04

073298395

Rock Creek at W. Palmer Rd nr Sulphur, OK

2/28/2023

13:02:18

8.44

Fair

Synoptic

AM-05

073298396

Cochran Creek nr Sulphur, OK

2/28/2023

13:59:45

2.78

Fair

Synoptic

AM-06

07329840

Rock Creek below Cunningham Well, 01N-03E-23 CCDC

2/28/2023

15:04:34

20.8

Fair

Synoptic

AG-01

073298507

Travertine Creek above U.S. 177 at Sulphur

3/1/2023

12:22:27

5.55

Fair

Continuous

AG-02

07329852

Rock Creek at Sulphur, OK

3/1/2023

9:29:46

23.1

Fair

Continuous

AM-07

07331183

Mill Creek at Hwy 7 nr Sulphur, OK

3/1/2023

15:48:38

0.19

Fair

Synoptic

AG-03

07331185

Mill Creek near Sulphur, OK

3/1/2023

14:20:07

0.20

Poor

Continuous

AM-08

07331188

Mill Creek NW of Mill Creek, OK

3/1/2023

17:02:15

3.23

Fair

Synoptic

AG-04

07331200

Mill Creek near Mill Creek, OK

2/28/2023

15:21:19

8.74

Fair

Continuous

2023

Hydrologic Data Comparison: Phase 1 to Phase 2 25 Table 6. Discrete discharge measurements made as part of the 2022 and 2023 seepage runs in and near the study area for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.—Continued [USGS, U.S. Geological Survey; ft3/s, cubic foot per second; blw, below; OK, Oklahoma; nr, near; N, north; E, east; W, west; Rd, road; 3Mile, Threemile; abv, above; Cr, Creek; Rvr, River; CCDC, southwest quarter of the southeast quarter of the southwest quarter of the southwest quarter; Br, branch; RSVR, reservoir; Br, branch; RSVR, reservoir. Dates are in month/day/year format. Times are in hour:minute:second format. Data are from USGS (2024a). Measurement ratings: excellent, within 2 percent of the actual flow; good, within 5 percent; fair, within 8 percent; and poor, differs from the actual flow by more than 8 percent (Turnipseed and Sauer, 2010)]

Map identifier (figs. 8, 9)

USGS station number

USGS station name

Measurement date

Measurement time

Discharge, in ft3/s

Measurement rating

Type of streamgage1

2023—Continued AG-05

07331205

Mill Cr at Mouth of 3Mile Cr near Mill Cr, OK

3/1/2023

11:27:49

6.90

Fair

Continuous

AM-09

07331212

Threemile Creek near Mill Creek, OK

2/28/2023

13:38:05

0.23

Fair

Synoptic

AM-10

07331214

Threemile Ck at Jewel 3/1/2023 Sikes Rd nr Mill Creek, OK

9:45:28

0.55

Poor

Synoptic

AG-06

07331293

Pennington Creek North of Mill Creek, OK

2/28/2023

10:22:00

Excellent

Synoptic

AM-12

07331294

Pennington Creek nr Mill Creek, OK

2/28/2023

10:39:00

Excellent

Synoptic

AG-07

07331295

Pennington Creek East of Mill Creek, OK

2/28/2023

11:42:00

8.38

Fair

Continuous

AM-13

073312975

Spring Creek near Mill Creek, OK

2/28/2023

13:29:46

0.13

Fair

Synoptic

AG-08

07331300

Pennington Creek near Reagan, OK

2/28/2023

15:37:20

23.6

Poor

Continuous

AM-14

07331310

Keel Creek near Reagan, Ok

2/28/2023

16:35:08

0.41

Fair

Synoptic

AM-17

07332302

Blue River near Roff, OK

3/1/2023

11:57:08

16.3

Fair

Synoptic

AG-09

07332305

Blue River West of Fittstown, OK

3/1/2023

10:45:21

12.7

Fair

Continuous

AG-10

07332307

Blue River near Franks, OK

3/1/2023

14:13:24

11.5

Fair

Continuous

AM-27

07332315

Little West Blue Creek nr Sulpher,2 OK

2/28/2023

12:44:00

Excellent

Synoptic

AG-11

07332348

Blue River North of Connerville, OK

3/1/2023

10:16:25

49.1

Fair

Continuous

AM-20

07332350

Blue River at Connerville, OK

3/1/2023

9:08:08

58.3

Fair

Synoptic

AM-21

07332355

Little Blue Creek nr Fittstown, OK

2/23/2023

11:02:04

Excellent

Synoptic

AM-22

07332358

Little Blue Creek at Hwy 377 at Pontoc, OK

2/23/2023

10:19:31

0.8

Poor

Synoptic

AM-23

07332360

Little Blue Creek nr Connerville, OK

2/28/2023

15:47:59

3.22

Good

Synoptic

Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Table 6. Discrete discharge measurements made as part of the 2022 and 2023 seepage runs in and near the study area for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.—Continued [USGS, U.S. Geological Survey; ft3/s, cubic foot per second; blw, below; OK, Oklahoma; nr, near; N, north; E, east; W, west; Rd, road; 3Mile, Threemile; abv, above; Cr, Creek; Rvr, River; CCDC, southwest quarter of the southeast quarter of the southwest quarter of the southwest quarter; Br, branch; RSVR, reservoir; Br, branch; RSVR, reservoir. Dates are in month/day/year format. Times are in hour:minute:second format. Data are from USGS (2024a). Measurement ratings: excellent, within 2 percent of the actual flow; good, within 5 percent; fair, within 8 percent; and poor, differs from the actual flow by more than 8 percent (Turnipseed and Sauer, 2010)]

Map identifier (figs. 8, 9)

USGS station number

USGS station name

Measurement date

Measurement time

Discharge, in ft3/s

Measurement rating

Type of streamgage1

2023—Continued AM-24

07332370

Blue River near Bromide, OK

2/28/2023

14:34:01

72.0

Fair

Synoptic

AM-25

07332380

Blue River ab3 Diamond Spring Br nr Connerville, OK

2/28/2023

13:32:09

85.6

Fair

Synoptic

AG-12

07332390

Blue River near Connerville, OK

3/1/2023

10:02:24

67.4

Poor

Continuous

AM-27

07334426

Delaware Creek nr Connerville, OK

2/28/2023

10:17:02

6.32

Fair

Synoptic

AG-13

07334428

Delaware Cr Blw Del Cr Site 9 RSVR nr Bromide, OK

2/28/2023

11:41:19

6.75

Good

Continuous

1“Synoptic” refers to sites that are sampled during a short-term investigation. “Continuous” refers to sites where data are collected on a regularly scheduled basis. 2This streamgage is near Sulphur, Okla., but the station name was entered incorrectly in the U.S. Geological Survey National Water Information System (NWIS) as “Sulpher” when the site was established. 3This streamgage is upstream from (above) Diamond Spring Branch. The abbreviation for “above” was entered incorrectly in NWIS as "ab" instead of "abv" when this station was established.

and spring, and evaporation losses reach their annual peak in the summer, which also causes spring discharge to decrease relatively more than during other seasons. For all seasons, spring discharges were generally highest during the spring because seasonal precipitation amounts are highest and because evapotranspiration rates in the spring are relatively low compared to those in the summer. Continuous spring discharge hydrographs from the Antelope Spring gage, Byrds Mill Spring gage (USGS streamgage 07334200), and Sheep Creek Spring gage were analyzed for the highest discharge periods during 2015–16 to identify flow regimes of this karst aquifer. Linear regression equations (regression curves) for spring discharge and time were examined for breaks (inflection points) in the recession slope, which are indicative of a change from one flow regime to another within the karst continuum (Otero, 2007). Diffuse flow is the amount of water that flows through the rock matrix (Kresic, 2013). Conduit flow is the amount of water that flows through rock fractures or conduits, which are interconnected solution cavities where the length is disproportionally larger than the height or width (Kresic, 2013). Recession curves were classified as different flow regimes based on their decay coefficient (α) in Milanović’s (1976) equation:

Q t  = Q 0 e α(t−t0  ), where

(1)

is discharge at time t, in cubic feet per second;

is initial discharge, in cubic feet per second;

is a mathematical constant equal to approximately 2.71828; it is the base of the natural logarithm and of its related inverse, the exponential function;

is time, in seconds; and

is time at the beginning of each recession slope, in seconds.

If the decay coefficient is 0.18, then conduit flow is the predominant flow type. If the decay coefficient is 0.09, then flow type consists of fracture flow or a mixture of conduit flow and diffuse flow (with conduit dominant). If the decay coefficient is 0.02, then flow type consists of fracture flow or a mixture of conduit flow and diffuse flow (with diffuse dominant). If the decay coefficient is 0.008, the diffuse flow is the predominant flow type (Milanović, 1976). As indicated by

Hydrologic Data Comparison: Phase 1 to Phase 2 27 97°00'

96°55'

96°50'

96°45'

96°40'

96°35'

96°30'

96°25'

34°45'

OKLAHOMA

34°40'

AG-09

AM-03

AG-10

AM-05

AM-27

AM-18

AM-22

AG-06

AG-05

AM-25

–0.01 AM-10

AG-07

AM-24

0.28

AG-13

AG-12

Keel Cree

AG-08 AM-14

34°20'

AM-26

7.63

–0.37

AM-23 AM-20

AM-13

.77

AM-09

AG-04

AM-12

–0.58

AG-11 8.79

0.3

0.27

AM-08

AM-19

0.3

0.28

AM-11

Threemile Creek

eek –9 ware C r D ela

AG-03

AM-21

0.26

ree k AM-07

Travertine Creek

34°25'

AM-04

Mill C

AM-01

–1.1

AM-17

k ree 9 e C 0.0 tle B l u .28 Lit 0

AG-02

AM-02

–0.51

ek Cre 0 ton ing nn Pe

34°30'

AM-16

AM-06 AG-01

AM-15

ek River .33 Cre 2 lue Bl st B We ttle Li

2.57

0.17

34°35'

Arbuckle-Simpson aquifer confined by post-Simpson groups

0.10 R o

ck C

re ek

Map area

0 Base modified from U.S. Geological Survey (USGS) 1:350,000-scale digital data Albers Equal-Area Conic projection North American Datum of 1983

5 5

10 MILES 10 KILOMETERS

Surficial extent of the Arbuckle-Simpson aquifer from Oklahoma Water Resources Board (2024a) Shaded relief derived from USGS, The National Map, 2024

EXPLANATION Unnamed upper confining unit deposited after the Simpson Group Surficial extent of the rocks that contain the eastern Arbuckle-Simpson aquifer

8.79 2.57 0.17 –0.58 –9.77

Measurement site and map identifier (table 6; USGS, 2024a)

Base-flow gain or loss, January 24–31, 2022, in cubic feet per second per mile 2.61 to 8.79

AM-01

2.01 to 2.60 0.01 to 2.00

AG-02

Synoptic base-flow measurement site (2022) Continuous discharge measurement site

−0.99 to 0 −10.00 to −1.00

Figure 8. Synoptic base-flow measurement sites and gaining and losing stream reaches crossing the surficial extent of the rocks that contain the eastern part of Arbuckle-Simpson aquifer, south-central Oklahoma, January 24–31, 2022.

28 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma 97°00'

96°55'

96°50'

96°45'

96°40'

96°35'

96°30'

96°25'

34°45'

OKLAHOMA

34°40'

Map area

34°35'

–1.3 6

AM-17

AM-02 AM-03

AM-05

ree k

Diamond Spring Branch

AG-13

AG-12

Keel Cree

0.6

AG-08 AM-14

34°20'

AM-24 AM-25

.7.711 ––1100

AM-10

AM-20

AM-13

eek 0.13 ware C r D ela

AM-23

AG-07

AM-26

3.45

eek Cr

AM-09

AG-04 AG-05

88.72 .72

AG-11 AM-12

9 2.3

AM-08

1.48

34°25'

AM-22

AG-06

Threemile Creek

AM-21

le B l u e Litt 0.67

AG-03

1.9 1

AM-01

Travertine Creek

0.27

AG-02

AM-07

ek Cre ton 0 ing nn Pe

34°30'

Mill C

AM-06

6 –0 . AG-01

AM-27

AG-10

ek 2.53 ue Cre River l st B We ttle Li

2.77 5 .45

AM-04

AG-09

–0 .688

1.92 R ock C

re ek

Arbuckle-Simpson aquifer confined by post-Simpson groups

0 Base modified from U.S. Geological Survey (USGS) 1:350,000-scale digital data Albers Equal-Area Conic projection North American Datum of 1983

5 5

10 MILES 10 KILOMETERS

Surficial extent of the Arbuckle-Simpson aquifer from Oklahoma Water Resources Board (2024a) Shaded relief derived from USGS, The National Map, 2024

EXPLANATION Unnamed upper confining unit deposited after the Simpson Group

Base-flow gain or loss, February 28–March 1, 2023, in cubic feet per second per mile 8.72 2 to 9

Surficial extent of the rocks that contain the eastern Arbuckle-Simpson aquifer

1.48 –0.67 –10.71

0.01 to 2.00 −0.99 to 0

Measurement site and map identifier (table 6; USGS, 2024a) AM-01

AG-02

Synoptic base-flow measurement site (2023) Continuous discharge measurement site

−10.72 to −1.00

Figure 9. Synoptic base-flow measurement sites and gaining and losing stream reaches crossing the surficial extent of the rocks that contain the eastern part of Arbuckle-Simpson aquifer, south-central Oklahoma, February 28–March 1, 2023.

Hydrologic Data Comparison: Phase 1 to Phase 2 29 the recession curves at the highest discharge periods, Antelope Spring yielded a higher decay coefficient than during the other periods of recession and exhibited more conduit flow than diffuse flow, followed by greater portions of mixed and diffuse flow (fig. 10A). This higher decay coefficient indicates that during periods of high-discharge recession, the groundwater system supplying Antelope Spring might include upper layers of the aquifer dominated by fractures and conduits, with a middle and lower section of the aquifer dominated by fractures, primary porosity, or both. As indicated by recession curves for the highest discharge periods for the Byrds Mill Spring and Sheep Creek Spring gages, decay coefficients are relatively lower and flow is mostly diffuse compared to Antelope Spring (fig. 10B, C). These lower decay coefficients indicate that the groundwater system near Byrds Mill and Sheep Creek Springs, near the upper levels of the formation, is likely dominated by diffuse drainage through primary porosity.

Discrete Springflow Measurements Discrete springflow measurements were made during 2022–23 at springs in the study area (table 1–2 in appendix 1) to document current springflows (at the time when the measurements were made) across the eastern part of the Arbuckle-Simpson aquifer for the Phase 2 study and to better understand changes in springflow over time (table 7). As explained in the “Introduction” section of this report, changes in the springflow over time across the aquifer could be an indicator of change in aquifer water storage amounts. Spring discharges were not measured and documented specifically for the Phase 1 studies, but historical spring discharges from the USGS NWIS database (1954–2017) (USGS, 2024a) were analyzed by the OWRB to identify which springs to include for the well-spacing rules for sensitive sole-source groundwater basins. Spring discharges for Phase 2 were measured during 2018–23, with some multiple measurements for the Phase 2 period of record specified in table 8 to indicate the period for which the Phase 2 mean discharge was calculated. The OWRB well-spacing rules are dependent on springs flowing greater than 50 gal/min (0.11 ft3/s) and 500 gal/min (1.11 ft3/s). Springflows as determined from historical discharge measurements were compared to Phase 2 discharge measurements (table 7). Eleven of the 17 spring sites had a decrease in discharge from the historical period to Phase 2 (table 7). Additional spring locations were documented, and discharge was measured for Phase 2 (table 1–2, appendix 1).

Groundwater Monitoring Groundwater-level data were collected in accordance with methods described in Cunningham and Schalk (2011). The Cunningham and Schalk report documents field methods for the establishment of a permanent measuring point and of other reference marks for a well site, how to measure water

levels using steel tapes and electric tapes, how to monitor continuous water levels with a pressure transducer, and how to test if a well is in connection with the aquifer. These methods described by Cunningham and Schalk are standard operating procedures used by the USGS for accuracy and verification of groundwater-level data collected. The continuous groundwater monitoring network that was established for Phase 2 consisted of 23 wells, with 18 wells completed in the Arbuckle Group and 5 wells completed in the Simpson Group (table 8). Six of the wells for Phase 2 were also used in Phase 1 for continuous groundwater levels monitoring. Groundwater-level data from Phase 1 were compared to those collected during Phase 2 at five wells, with the results indicating relatively unchanged mean groundwater levels (fig. 11). The periods of lowest groundwater levels (the “troughs” on the groundwater-level hydrographs) typically occurred during the summer and winter months, and the troughs were generally shallower during Phase 2 than during Phase 1. The peaks on the groundwater-level hydrographs (typically during the spring and fall months) during Phase 1 were sometimes slightly shallower or deeper or relatively unchanged compared to those of Phase 2. The mean depth of the wells being monitored in conjunction with this study that are completed in the portion of the eastern part of the Arbuckle-Simpson aquifer contained in the Arbuckle Group is 190 ft bls, excluding one well where the depth is approximately 920 ft bls (table 8). The mean depth of the wells being monitored in conjunction with this study that are completed in the portion of the eastern part of the Arbuckle-Simpson aquifer contained in the Simpson Group is 120 ft bls. The Arbuckle Group is exposed at the surface through most of the study area, and the part of the Arbuckle-Simpson aquifer contained in these rocks is primarily recharged through precipitation. The karstic nature of the aquifer allows for a somewhat flashy response in groundwater levels because recharge can flow quickly through conduits through fractures and along faults (Fairchild and others, 1990). Wells completed in the Arbuckle Group typically yield 200 to 500 gal/min (Fairchild and others, 1990). Water levels measured in wells completed in the Arbuckle Group are more variable compared to the water levels measured in wells completed in the Simpson Group; the variability in water levels is caused by seasonal changes in water use, precipitation, and evaporation, along with other seasonal changes. The Simpson Group is exposed at the surface in the western part of the study area, as well as a small section in the southeastern part of the study area (fig. 2). The Simpson Group is less karstic than the Arbuckle Group and primarily stores and transports water through diffuse flow via pore spaces in the sandstones that are part of the Simpson Group (Fairchild and others, 1990; Christenson and others, 2011). Flow through pore spaces is slower than flow through conduits and karst features, and as a result, groundwater levels in the Simpson Group respond to precipitation in a more subdued, less flashy way. The less karstic nature of the Simpson Group

30 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma A. Antelope Spring at Sulphur, Okla. (U.S. Geological Survey [USGS] station 07329849) 2.0

10 8

1.5

6 1.0 4 0.5

2 0

EXPLANATION

Precipitation at the Sulphur Mesonet climate station (fig. 1; Oklahoma Mesonet, 2023) Discharge (USGS, 2024a)

B. Byrds Mill Spring near Fittstown, Okla. (USGS station 07334200)

Precipitation, in inches

25 20

1.5

1.0

10 0.5

5 0

Spring discharge, in cubic feet per second

30 2.0

EXPLANATION

Precipitation at the Fittstown Mesonet climate station (fig. 1; Oklahoma Mesonet, 2023) Discharge (USGS, 2024a)

C. Sheep Creek Spring near Fittstown, Okla. (USGS station 343422096385101) 2.0

1.5

4 3

1.0

2 0.5 1 0 Jan. 1

2014

Apr. 1

July 1

2015

Oct. 1

Jan. 1

EXPLANATION

Apr. 1

July 1

Oct. 1

Jan. 1

2016

2017

Precipitation at the Fittstown Mesonet climate station (fig. 1; Oklahoma Mesonet, 2023) Discharge (USGS, 2024a) 0.008 Diffuse flow

0.02 - Fracture flow or mixture of conduit flow and diffuse flow (with diffuse dominant)

Recession coefficient

0.09 - Fracture flow or 0.18 - Conduit mixture of conduit flow flow and diffuse flow (with conduit dominant)

Figure 10. Discharge and spring recession curves classified by flow regime and precipitation for A, Antelope Spring, B, Byrds Mill Spring, and C, Sheep Creek Spring, south-central Oklahoma, 2014–17.

Hydrologic Data Comparison: Phase 1 to Phase 2 31 Table 7. Differences in mean discharge at spring sites between historical period of record and 2018–23 (Phase 2), eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma. [USGS, U.S. Geological Survey; ft3/s; cubic feet per second. Data are from USGS (2024a)]

Mean discharge for Phase 2 study, in ft3/s

Discharge difference and increase (↑) or decrease (↓) from historical to Phase 2

USGS station number

Latitude, in decimal degrees

Longitude, in decimal degrees

Historical period of record

Mean discharge for historical period of record, in ft3/s

07329849

34.504444

−96.941111

1985–2017

2.86

2018–23

2.19

0.67 ↓

07332389

34.386675

−96.603775

1977

0.10

2020–23

0.27

0.17 ↑

07334238

34.573056

−96.647500

2014–17

2.96

2018–23

2.85

0.11 ↓

342216096314001

34.379694

−96.526972

1977

0.78

2018

0.24

0.54 ↓

342233096444501

34.375333

−96.746972

1977

0.15

2018

0.10

0.05 ↓

342254096425501

34.382389

−96.715389

2004

1.30

2018

0.92

0.38 ↓

342335096462501

34.392861

−96.774000

1977

1.00

2018

0.69

0.31 ↓

342342096464801

34.394889

−96.781056

2007

0.15

2018

0.30

0.15 ↑

342414096364701

34.404056

−96.613278

1977

0.35

2018

0.48

0.12 ↑

342511097064501

34.419667

−97.111917

1992

3.01

2018

1.28

1.73 ↓

342718096380401

34.454972

−96.634444

1997

0.98

2018

0.93

0.04 ↓

342911096373701

34.486481

−96.627227

1985

1.05

2023

1.70

0.64 ↑

343007096581601

34.502000

−96.971200

2002

0.02

2018

0.15

0.13 ↑

343012096581301

34.502800

−96.970200

1988

0.07

2018

0.03

0.04 ↓

343114096353101

34.520500

−96.607806

1977

0.45

2018

0.01

0.44 ↓

343241096360201

34.544750

−96.600833

1977

0.60

2018

0.55

0.05 ↓

343422096385101

34.572778

−96.647500

2004

2.41

2018

3.49

1.08 ↑

also lends itself to lower well yields than the Arbuckle Group, typically 100 to 200 gal/min (Fairchild and others, 1990; Christenson and others, 2011). Wells completed in the part of the aquifer contained in either the Arbuckle or Simpson Group exhibit seasonal changes and patterns in water levels. During the spring and fall, when precipitation is seasonally at its highest, the water levels in both aquifers tend to be higher compared to water levels during the winter and summer months. During the summer, water levels tend to be lower than in any of the other seasons because of less precipitation and increased water use and evapotranspiration; summer is when most groundwater is withdrawn for crop irrigation, lawn watering, and other activities such as filling swimming pools, washing cars, and watering gardens. Water levels in the study area during the summer and winter, particularly in the Arbuckle Group of the Arbuckle-Simpson aquifer, appeared to be generally decreasing during Phase 2. These declining water levels were most likely caused by decreasing precipitation (fig. 11) but could also have been caused by increased water use or evapotranspiration.

Phase 2 period of record

Potentiometric Surfaces A potentiometric surface is a surface of equal hydraulic head or potential, typically depicted by a map of equipotential lines such as water-table elevations (Sharp, 2024) and thus represents a snapshot of groundwater levels (commonly referred to as the water table) across the aquifer for a specific point in time. Specific points on potentiometric-surface maps are roughly equivalent to the level to which water will naturally rise in a tightly cased well. Potentiometric-surface maps can be used to help identify groundwater-flow directions, delineate subsurface groundwater basins, and estimate changes in groundwater storage by comparing potentiometric surfaces from different time periods (Driscoll, 1986). The altitudes of potentiometric surfaces of the Arbuckle-Simpson aquifer were calculated by collecting groundwater-level measurements at 57 groundwater wells across the study area in 2022 (fig. 12) and 56 wells in 2023 (fig. 13). These measurements were collected during base-flow conditions in mid-February 2022 and 2023, when evapotranspiration rates and groundwater use are less compared to other months. A potentiometric surface is a theoretical topographical surface which represents the fluid potential of groundwater within an aquifer. Potentiometric surfaces were constructed in ArcGIS Pro by combining synoptic water-level data with a

32 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 8. Periods of record for continuous groundwater monitoring wells completed in the Arbuckle or Simpson Group across the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma. [USGS, U.S. Geological Survey; bls, below land surface. Phase 1 refers to data collected primarily during 2003–02, and Phase 2 refers to data collected primarily during 2018–23. Data are from USGS (2024a). Dates are in year-month-day format. --, no data]

USGS station number

USGS station name

Well depth, in feet bls

Period of record

Phase 1, continuous groundwater monitoring wells completed in the Arbuckle Group 343457096404501

01N-06E-04 CAD 1 Fittstown GW well1

396

1980-10-05 to currently operating (2024)

343017096561501

01S-03E-01 ABA 1 CNRA GW WELL 22

238

1986-03-24 to 1989-06-20 and 2015-05-04 to currently operating (2024)

342633096494401

01S-04E-25 ADD Johnston 25

2006-09-21 to currently operating (2024)

342527096493301

01S-05E-31 CBD JOHNSTON 313

122

2006-09-21 to currently operating (2024)

Phase 2, continuous groundwater monitoring wells completed in the Arbuckle Group 342155096412001

02S-06E-20 DAD 1 ARB12

2019-12-18 to currently operating (2024)

342336096381201

02S-06E-11 DDA 1 ARB08

160

2019-10-07 to currently operating (2024)

342556096535601

01S-04E-32 AAA 1 ARB17

2019-11-26 to currently operating (2024)

342618096380101

01S-06E-25 CBD 1 ARB03

302

2019-08-13 to currently operating (2024)

342619096411001

01S-06E-28 CBD 1 ARB064

220

2019-08-27 to currently operating (2024)

342921096381601

01S-06E-11 AAD 1 ARB075

2019-09-10 to currently operating (2024)

343058096484101

01N-05E-31 ADA 1 ARB15

2020-01-09 to 2023-02-13

343248096455101

01N-05E-22 ABC 1 ARB11

215

2019-12-18 to currently operating (2024)

343445096494301

01N-04E-01 DDD 2 ARB01

2019-07-16 to currently operating (2024)

343513096505301

01N-04E-02 ADC 1 ARB09

920

2019-11-22 to currently operating (2024)

343531096403801

01N-06E-04 ABB 2 ARB04

135

2019-08-14 to currently operating (2024)

343534096453701

01N-05E-03 ABB 2 ARB10

157

2019-11-23 to currently operating (2024)

343623096421801

02N-06E-31 AAA 1 ARB05

115

2019-08-17 to currently operating (2024)

Phase 2, continuous groundwater monitoring wells completed in the Simpson Group 342510096363901

02S-07E-06 BAA 2 SIMP02

101

2019-09-10 to currently operating (2024)

342837096560801

01S-03E-13 AAB 1 SIMP04

112

2019-12-13 to currently operating (2024)

343240096523201

01N-04E-22 BCA 1 SIMP05

104

2020-01-08 to currently operating (2024)

343349096523101

01N-04E-15 BAB 1 SIMP06

170

2020-01-08 to currently operating (2024)

343352096462801

01N-05E-10 CCC 2 SIMP07

104

2019-07-18 to currently operating (2024)

1OWRB ID 89386 during Phase 1 study (Christenson and others, 2011). 2OWRB ID 89387 during Phase 1 study (Christenson and others, 2011). 3OWRB ID 92477 during Phase 1 study (Christenson and others, 2011). 4OWRB ID 93617 during Phase 1 study (Christenson and others, 2011). 5OWRB ID 86266 during Phase 1 study (Christenson and others, 2011).

digital elevation model (DEM) and generating contours around the derived static head measurements (depth to water, in feet below land surface datum). Contours were adjusted to remedy irregularities resulting from automated contour generation and known inconsistencies in the study area. The resultant map displays a surface that can be used to interpret the direction groundwater will flow throughout a given aquifer.

Groundwater-level data were used to create two potentiometric-surface maps over the main area of the eastern part of the Arbuckle-Simpson aquifer (figs. 12–13). Both maps show a decrease in water-level altitude from the northwest to the southeast indicating the general direction of groundwater flow through the aquifer while also displaying some variation from year to year. Despite some fluctuations, potentiometric surfaces for the Arbuckle-Simpson aquifer indicate that

Hydrologic Data Comparison: Phase 1 to Phase 2 33 A. Water levels for USGS groundwater monitoring well 343457096404501, completed in the Arbuckle Group

Phase 1

Phase 2

12 10

100

110

120

130

B. Water levels for USGS groundwater monitoring well 342527096493301, completed in the Arbuckle Group

Phase 1

Phase 2

16 14 12

2 0

40 24

Depth to water, in feet below land surface

C. Water levels for USGS groundwater monitoring well 343017096561501, completed in the Arbuckle Group Phase 2

Phase 1

16 14 12 10

D. Water levels for USGS groundwater monitoring well 342619096411001, completed in the Arbuckle Group Phase 2

16 14

Phase 1

12 10

6 4

100 35

E. Water levels for USGS groundwater monitoring well 342837096560801, completed in the Simpson Group

Phase 1

10 Phase 2

6 4

1/1/2003

16 14

Daily precipitation, in inches

1/1/2005

1/1/2007

1/1/2009

1/1/2011

1/1/2013

1/1/2015

1/1/2017

1/1/2019

1/1/2021

1/1/2023

Figure 11. Depth to water and daily precipitation for U.S. Geological Survey (USGS) monitoring wells completed in the A–D, Arbuckle Group and E, the Simpson Group, south-central Oklahoma, 2003–23.

34 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma 96°55'

96°45'

96°40'

Map area

0 1,04

1,055.6

1,0 60

1,0

920 880 860.8 885.6

973.5

922.1 942.4 919.8

in on

ee Cr k

Creek are law e D

0 90

940

MURRAY COUNTY

COAL COUNTY

931.5

922.1

ree

ll C

998.1

1,0

ckh

980

1,000.5

1,028.3

1,06

1,078.8

1,024.3

1,120.3

1,015.4

923.9

899.7

CARTER COUNTY

Base from U.S. Geological Survey (USGS) digital data, various scales 0 Albers Equal-Area Conic projection, standard parallels 29°30' and 45°30' N., central meridian 96°00' W. North American Datum of 1983 0

5 5

10 MILES

Surficial extent of the Arbuckle-Simpson aquifer from Oklahoma Water Resources Board (2024a)

10 KILOMETERS

EXPLANATION Surficial extent of the Arbuckle and Simpson Group rocks that contain the eastern part of the Arbuckle-Simpson aquifer 980

1,055.6

ATOKA COUNTY

1,041.1

1,043.4

JOHNSTON COUNTY

1,040

1,008

900

1,090

974.5 960

1,013.5

1,046.2

1,076.1

1,0

1,026.2

940

1,1

Creek

1,081.9

1,092.3

1,078.8

1,082.2

r ive

1,092.5

1,080

orn

1,084.2

1,035.4 1,040.3 1,028.4 1,076.6

eR Blu

,100

1,086.8

34°30'

1,036.5 1,0 40 1,033.6

1,036.2

1,129.9 1,130.2

1,120

1 ,0 8

1,102.2

Roc kC ree k

1,094.4

1,101.6

1,14

1,146.3 1,155.5

ek l Cre Mil reek ep C 1,034.7 1,037.5 She 1,036.8 1,032.9 1,091.8

1,102.9

34°35'

1,095.9

96°25'

OKLAHOMA

Unnamed upper confining unit deposited after the Simpson Group

34°20'

96°30'

HUGHES COUNTY

34°40'

34°25'

96°35'

1,0

GARVIN COUNTY

34°45'

96°50'

PONTOTOC COUNTY

97°00'

Potentiometric contour—Shows altitude at which water level would have stood in tightly cased wells, February 2022. Dashed where approximately located. Contour interval 20 feet. Datum is North American Vertical Datum of 1988 (NAVD 88) Well completed in the Arbuckle-Simpson aquifer and water-level altitude, in feet above NAVD 88 (USGS, 2024a)—One symbol could represent more than one well

Figure 12. Potentiometric surface of the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma, February 2022.

Hydrologic Data Comparison: Phase 1 to Phase 2 35 96°55'

1,094.2 1,086.8

1,077.2

1,160

1,047.8

1,0

900

1,019.4

1,003.5

934.6

980

928.9

ree

940

Creek are law e D

924.4

930.1

MURRAY COUNTY CARTER COUNTY

Base from U.S. Geological Survey (USGS) digital data, various scales Albers Equal-Area Conic projection, standard parallels 29°30' and 45°30' N., central meridian 96°00' W. North American Datum of 1983

0 0

10 MILES Surficial extent of the Arbuckle-Simpson aquifer from Oklahoma Water Resources Board (2024a)

5 5

COAL COUNTY

1,019.4 976.2

939.5 926.0 926

960

ee Cr

ll C

1,0

841.1 884.8

880

1,0

1,060.1 1,060.1

1,017.6

1,038.3

1,071.6

1,083.2

1,120

1,031.0

1,060 1,028.2 1,009.7 1,040 1,018.5

1,169.4

1,026.5

1,133.5

r ive

1,079.9

eR Blu

1,1

Creek

060

1,121.7

1,080.4 1,200 1,160

1,077.6 1,080 1,078.5 1,072.2 1,060 1,041.6 1,040 1,052.2

1,090.2 1,090.2

orn

1,10

1,219.7

1,160 1,140 0 1,12

34°30'

1,122.3

1,040

1,14

1,094.6

10 KILOMETERS

EXPLANATION Surficial extent of the Arbuckle and Simpson Group rocks that contain the eastern part of the Arbuckle-Simpson aquifer 980

976.2

ATOKA COUNTY

1,120 1,060

600

1,149.7

Mi 1,101.8 1,041.3 reek 1,061.8 ep C 1,033.9 She 1,032.6 1,037.2 1,036.0 1,035.7 1,01 400 1,039.8 1,033.7 1,040.8 1,028.5 1,075.9 1,080

JOHNSTON COUNTY

1,166.4

eek ll Cr

1,1

920 900

1,090.3

1,0 80

1,1

Roc kC ree k

96°25'

Map area

1,137.6

ckh

96°30'

OKLAHOMA

34°35'

96°35'

HUGHES COUNTY

Unnamed upper confining unit deposited after the Simpson Group

34°20'

96°40'

1,06 0

34°40'

34°25'

96°45'

1,1 ,0260

GARVIN COUNTY

34°45'

96°50'

PONTOTOC COUNTY

97°00'

Potentiometric contour—Shows altitude at which water level would have stood in tightly cased wells, February 2023. Dashed where approximately located. Contour interval 20 feet. Datum is North American Vertical Datum of 1988 (NAVD 88) Well completed in the Arbuckle-Simpson aquifer and water-level altitude, in feet above NAVD 88 (USGS, 2024a)—One symbol could represent more than one well

Figure 13. Potentiometric surface of the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma, February 2023.

36 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma regional groundwater flow is toward the southeast, where streams and springs discharge at the aquifer boundary, which is consistent with the findings of Christenson and others (2011). Water-level altitude measurements used for the 2022 potentiometric surface ranged from 861 to 1,163 ft above the North American Vertical Datum 1988 (NAVD 88), with a mean of 1,039 ft above NAVD 88 (USGS, 2024a). Water-level altitudes used for the 2023 potentiometric surface ranged from 885 to 1,220 ft above NAVD 88, with a mean of 1,050 ft above NAVD 88. Although the variance and difference in mean values from 2022 to 2023 are not substantial, the mapped potentiometric contours have differences. The largest differences in water-level altitudes between 2022 compared 2023 are in an area containing four wells east of Pennington Creek. The water-level altitudes were higher in 2023 than in 2022: 1,086.8, 1,081.9, 1,092.3, and 1,092.5 ft above NAVD 88 for 2022 and 1,079.9, 1,077.2, 1,169.4, and 1,219.7 ft above NAVD 88 for 2023, respectively. Even with other examples of localized differences between the two maps, general patterns remained similar in 2022 and 2023. In Phase 1, three potentiometric-surface maps were prepared and analyzed. The measurements used to generate these maps were collected during August 7–16, 1995; June 2006; and September 2006 (Christenson and others, 2011). As expected, these maps feature a slope from a topographic high between Blue River and Pennington Creek just east of the confined part of the eastern Arbuckle-Simpson aquifer to the southeast. This slope to the southeast from a topographic high is common to all Arbuckle-Simpson potentiometric-surface maps. Although this overarching pattern holds true as illustrated for Phase 1 and Phase 2 maps (figs. 12–13), localized variations for different time periods were observed. The three potentiometric-surface maps produced for Phase 1 exhibit contours that “V” upstream near Delaware Creek in the southeast part of the main aquifer area (figs. 18–20 in Christenson and others, 2011). This “V” of contours is still slightly indicated but is harder to detect in the Phase 2 potentiometric-surface maps (figs. 12, 13) compared to those from Phase 1. This difference in prominence of contours could be due to the higher density of measurements in this area in Phase 1 that allowed detection of smaller scale features. This interpretation of the effects of measurement density on the ability to detect smaller scale features can be extended to other differences between the potentiometric surface; approximately 90 groundwater-level measurements were used to create the 2006 map compared to 57 and 56 groundwater-level measurements used for the 2022 and 2023 maps, respectively. Across the eastern part of the Arbuckle-Simpson aquifer, groundwater levels were slightly higher in altitude (nearer the ground surface) during Phase 2 compared to Phase 1. The variation in the potentiometric surfaces between Phase 1 and Phase 2 could be attributed to the time at which

measurements were collected. For Phase 2, water levels were measured February 14–17, 2022, and February 13–16, 2023, during base-flow conditions. Collecting groundwater-level measurements during base-flow conditions reduces effects from evapotranspiration, peak water use, and precipitation. In contrast to the Phase 2 groundwater levels, Phase 1 groundwater levels were not measured during base-flow conditions.

Recharge Even though aquifer recharge can be a result of many different processes or a combination of processes, the dominant recharge mechanism for the eastern part of the Arbuckle-Simpson aquifer is infiltration of precipitation through the soil. This precipitation recharge takes place when precipitation falls on the land surface and subsequently percolates into the unsaturated zone. Evapotranspiration is the combination of evaporation and transpiration, with evaporation being water that transpires from a surface to the atmosphere and transpiration being water taken up by plants and released as vapor into the atmosphere (Sharp, 2024). The amount of precipitation that successfully infiltrates into soil and passes through an unsaturated zone for recharge to the water table is dependent on many factors such as the amount of water stored in the unsaturated zone, the slope of the land surface, the composition of the rocks and soils that form the aquifer, the type of vegetation and general land use overlying the aquifer, and the intensity, season, and duration of precipitation. Owing to the substantial number of variables that affect recharge via infiltration from precipitation, estimates are difficult to quantify. Two methods were used in this study to estimate recharge: (1) a recession-curve displacement method, referred to as the RORA method (Rorabaugh, 1964; Rutledge, 1998) and implemented as the RORA program, was used to estimate recharge in a watershed upstream from a selected streamgage, and (2) the Soil-Water-Balance (SWB) code (Westenbroek and others, 2010) was used to model spatially distributed recharge rates across the aquifer.

RORA Recession-Curve Displacement Method For Phase 1 and Phase 2, the basin-scale recession-curve displacement method developed by Rorabaugh (1964) that was implemented in the USGS Groundwater Toolbox as the “RORA program” (Barlow and others, 2015) was used to estimate recharge within watersheds upstream from selected streamgages in the eastern part of the Arbuckle-Simpson aquifer (Rorabaugh, 1964; Rutledge, 1998). The RORA program is used to estimate the change in the total potential groundwater discharge (base flow) at a critical time after the peak (peak in streamflow caused by higher rates of precipitation and runoff) by extrapolation from the pre-peak and the post-peak recession periods (Rutledge, 1998).

Hydrologic Data Comparison: Phase 1 to Phase 2 37 Table 9. Quarterly recharge calculated for U.S. Geological Survey streamgage 07332390 at Blue River near Connerville, Oklahoma, for Phase 1 (1977–2008) and Phase 2 (2018–22) periods. [Subsurface watershed area (from fig. 21 and table 8 in Christenson and others, 2011) using the basin-scale recession-curve displacement method (Rorabaugh, 1964; Rutledge, 1998); Phase 1 mean values include only the water years during 1977–2008 that are listed in this table; Phase 2 mean values are for water years 2018–22]

Subsurface Median watershed recession index area (days per log (square miles) cycle) 88.4

150.86

67.10

Recharge (inches) Water year

Season October– December

January–March

April–June

July– September

Annual total

1977

1.42

4.04

2.09

1.38

8.93

1978

1.26

2.36

3.24

1.31

8.17

1979

1.28

2.29

2.94

1.16

7.67

2004

2.13

2.32

1.31

1.54

7.30

2005

5.13

6.13

1.19

1.39

13.84

2006

1.48

2.19

2.11

0.76

6.54

20071

1.96

3.32

16.04

0.01

21.33

2008

1.77

2.9

2.21

1.09

7.97

Phase 1 mean1

2.05

3.19

3.89

1.08

10.22

2009

1.03

1.5

4.21

1.84

8.58

2010

8.7

6.38

4.8

2.98

22.86

2011

2.14

1.93

1.47

1.55

7.09

2012

1.35

2.78

1.62

1.32

7.07

2013

1.14

1.56

1.74

1.46

5.9

2014

1.34

2.05

1.77

1.43

6.59

20151

1.31

1.88

11.6

5.71

20.54

2016

9.68

5.91

8.96

1.81

26.36

2017

1.69

2.45

3.47

4.53

12.14

2018

1.83

4.3

4.84

4.97

15.94

2019

10.95

9.34

7.96

3.16

31.41

2020

7.13

16.25

6.01

2.87

32.26

2021

1.74

3.15

7.99

2.11

14.99

2022

1.41

1.32

2.94

1.04

6.71

Phase 2 mean

4.61

6.87

5.95

2.83

20.3

1Computation was ambiguous because of large-scale flooding in 2007 or 2015, respectively.

Recharge from each precipitation event is assumed to be the difference between the groundwater discharge to the stream and the groundwater discharge that would have happened at the same time in the absence of the recharge event, based on extrapolation of the streamflow hydrograph prior to the recharge event. Recharge commonly is divided by the area of the drainage basin and expressed as a rate in inches per year. The areas of the subsurface watersheds (Christenson and others, 2011, fig. 21 and table 8) were used as the watershed areas for this study. Owing to assumptions and stipulations inherent to this method of recharge estimation, three USGS streamgages were selected by Christenson and others (2011) for analysis in a Phase 1: the Blue River streamgage

(table 9), the Pennington Creek near Reagan gage (table 10), and Honey Creek below Turner Falls near Davis (USGS streamgage 07329780). The Honey Creek below Turner Falls near Davis streamgage is not located in the eastern part of the Arbuckle-Simpson aquifer and therefore is not listed in table 9 or 10. The period of record analyzed for recharge for the Blue River streamgage (table 9) for phase 1 included the years 1977–79 and 2004–08. The period of record analyzed for recharge for the Pennington Creek near Reagan streamgage (table 10) for phase 1 included the years 2004–2008. These sites were used in Phase 2 to allow for direct comparison and discussion of temporal variations. The USGS Groundwater Toolbox programs RECESS (Rutledge, 1998) and RORA

38 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 10. Quarterly recharge calculated for U.S. Geological Survey streamgage 07331300 at Pennington Creek near Reagan, Oklahoma, for Phase 1 (2004–08) and Phase 2 (2018–22). [Subsurface watershed area (from fig. 21 and table 8 in Christenson and others, 2011) using the basin-scale recession-curve displacement method (Rorabaugh, 1964; Rutledge, 1998); Phase 1 mean values include only the water years during 2004–08 that are listed in this table; Phase 2 mean values are for water years 2018–22]

Median Watershed recession index area (days per log (square miles) cycle) 61.9

94.06

61.42

Recharge (inches) Water year

2004

Quarters October– December

January–March

April–June

July– September

Yearly total

0.78

2.03

0.9

1.35

5.06

2005

3.51

5.12

1.22

1.01

10.9

2006

1.03

1.18

1.98

0.64

4.83

2007

1.76

2.87

11.3

0.51

16.4

2008

0.92

1.91

1.35

0.67

4.85

Phase 1 mean1

1.6

2.62

3.34

0.84

8.4

2009

0.69

0.32

3.76

0.96

5.73

2010

4.55

3.81

3.72

1.7

13.78

2011

0.95

0.79

0.8

0.34

2.88

2012

0.63

2.29

1.45

0.38

4.75

2013

0.39

0.49

1.53

0.82

3.23

2014

0.74

0.92

1.06

0.85

3.57

20151

0.87

2.12

14.53

3.15

20.67

2016

8.3

4.43

5.59

0.85

19.17

2017

0.54

1.01

2.88

1.42

5.85

2018

0.61

2.25

3.15

3.48

9.49

2019

7.04

5.92

4.95

1.03

18.94

2020

3.64

9.44

3.77

1.06

17.91

2021

0.6

1.66

4.65

0.98

7.89

2022

0.42

0.21

0.91

0.23

1.77

Phase 2 mean

2.46

3.9

3.49

1.36

11.2

1Computation was ambiguous because of large-scale flooding in 2007 or 2015, respectively.

(Barlow and others, 2015) were used in conjunction with streamgage data to compute the recharge values shown in tables 9 and 10. The use of these tools is elaborated upon in Christenson and others (2011). The mean annual estimated recharge determined by using the RORA program for the eastern part of the Arbuckle-Simpson aquifer was 16.5 inches per year (in/yr; 43 percent of the 37.97 inches of mean annual precipitation) during 2018–22. Phase 2 mean annual recharge determined by using the RORA program was greater than Phase 1 mean annual recharge at the same two sites measured and analyzed for Phase 1 and Phase 2. For the Blue River streamgage, the mean annual recharge increased by 98 percent from Phase 1 to Phase 2. For the Pennington Creek near Reagan gage, the mean annual recharge increased by 33 percent from Phase 1 to Phase 2.

Upstream anthropogenic streamflow augmentation from producing mines affects recharge estimates obtained from the RORA program by increasing the part of the hydrograph that is interpreted by the RORA program as recharge to the aquifer (fig. 7). Because these augmentations to streamflow were not measured and are difficult to estimate and separate from the streamflow hydrograph, the estimates of recharge derived by the RORA program are likely overestimated for basins where these releases occurred.

Soil-Water-Balance Code The SWB (Westenbroek and others, 2010) code was run to estimate the amount and spatial distribution of daily groundwater recharge to the eastern part of the Arbuckle-Simpson aquifer only for the years from 2019 through 2022 of the Phase 2 period because most of the

Hydrologic Data Comparison: Phase 1 to Phase 2 39 groundwater well data collection in Phase 2 started in 2019 (table 8). At the time the SWB code was run for this report, the climate data for 2023 were not available yet. SWB is a modified Thornthwaite and Mather (1957) SWB method that uses gridded climate data and landscape characteristics to calculate recharge by using the following equation: R = (P + S + Ri) – (Int + Ro + Pet) – ΔSm,(2) where

is recharge, in inches per day;

is precipitation, in inches per day;

is snowmelt, in inches per day;

is surface runoff inflow, in inches per day;

Int

is plant interception, in inches per day;

is surface runoff outflow, in inches per day;

Pet

is potential evapotranspiration, in inches per day; and

ΔSm

is the change in soil moisture, in inches per day.

Data inputs that are used in the SWB code include precipitation, air temperature, soil-water storage capacity, hydrologic soil group, land-surface flow direction, and land-cover type. The user-specified grid for the eastern part of the Arbuckle-Simpson aquifer SWB code consisted of 2,180 columns by 1,831 rows of cells that were each 328 by 328 ft. Climate data inputs included daily grids of precipitation data and minimum and maximum air temperature during 2019–22 from the Daymet climate database (Thornton and others, 2024). Soil properties (soil-water storage capacity and hydrologic soil group) were obtained from the gridded Soil Survey Geographic database (U.S. Department of Agriculture, 2024). Land-cover types were obtained from the National Land Cover Database (Multi-Resolution Land Characteristics Consortium, 2024) and resampled to the SWB model grid resolution by using the most common land-cover type within each cell. Surface runoff was derived by using the D8 method (Greenlee, 1987) to calculate the land-surface gradient from a 10-meter DEM (USGS, 2015). Depressions were filled by using the ArcGIS Fill tool (Esri, 2024) after the DEM was resampled to the SWB model grid size. Filling depressions in the DEM ensures correct routing of surface runoff and eliminates isolated sink features that would result in unrealistically high amounts of recharge. The Hargreaves and Samani (1985) method for calculating evapotranspiration was used for a reference latitude of 34.240000 to 34.740000 degrees. Land-cover types were used in conjunction with hydrologic soil groups to partition daily precipitation into plant interception (Int)

and surface runoff (Ri and Ro) components and assign plant root-zone depths. The root-zone depths for grassland/ herbaceous and pasture (the dominant land-cover types in the study area) varied with soil texture but ranged from about 0.8 to 1.5 ft. The maximum volume of water available in the root zone was calculated by multiplying the soil-water storage capacity by the root-zone depth. Changes in soil moisture (ΔSm) exceeding the soil-water storage capacity were assumed to be recharge (R) to the saturated zone. Smaller root-zone depths resulted in increased recharge and decreased evapotranspiration of water from the root zone whereas larger root-zone depths resulted in decreased recharge and increased evapotranspiration of water from the root zone. Recharge from irrigation was not simulated by SWB but was assumed to be negligible given the relatively small amount of irrigation groundwater use in the study area. Recharge from precipitation was assumed to occur where the eastern part of the Arbuckle-Simpson aquifer is unconfined. The portion confined by the post-Simpson Pennsylvanian units was analyzed by using the SWB code but was not included in the mean recharge calculation for the study area (fig. 14). The mean annual SWB-estimated recharge for the eastern part of the Arbuckle-Simpson aquifer was 4.85 in/yr (or 13 percent of the 37.97 inches of mean annual precipitation) for the 2019–22 period (fig. 4A). The annual SWB-estimated recharge for the eastern part of the Arbuckle-Simpson aquifer was 7.2 inches for 2019, 5.9 inches for 2020, 2.6 inches for 2021, and 3.6 inches for 2022. Mean annual recharge estimated by using the RORA program for Phase 2 (2018–22) was 16.5 in/yr, which is greater than the mean annual recharge of 4.85 in/yr estimated by using SWB for Phase 2 (2019–22). The SWB code cannot be used to simulate interactions between surface-water and groundwater features. In locations where the water table is beneath the bottom of the root zone, the SWB code can be used to produce reasonable annual or monthly values. The depth from the bottom of the root zone to the top of the water table is not considered in the estimation of recharge because there may be appreciable travel time through the unsaturated zone. Simulating the unsaturated zone was outside the scope of this project. Using the SWB code in areas with wetlands, springs, and lakes where the water table is close to the land surface produced unrealistic annual or monthly values because there is no provision for recharge rejection in the form of saturation excess (other than a maximum recharge rate that can be specified for a land use and soil type). Because the eastern part of the Arbuckle-Simpson aquifer is a karst aquifer, recharge estimates obtained by using the SWB code were compared with estimates obtained by using other recharge methods (such as the RORA program). SWB code can nonetheless be used to create reliable spatially gridded recharge estimates for the study area with spatial variations in recharge across different surficial features of the eastern part of the Arbuckle-Simpson aquifer. The alluvial sediments and soils near streams have higher recharge rates

40 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma 97°00'

96°55'

96°50'

96°45'

96°40'

96°35'

96°30'

96°25'

34°40'

34°35'

34°30'

34°25'

34°20'

Base from U.S. Geological Survey digital data, various scales Albers Equal-Area Conic projection Standard parallels 29°30' and 45°30' N Central meridian 96°00' W North American Datum of 1983

0 0

5 5

10 MILES 10 KILOMETERS

EXPLANATION Spatially distributed, mean annual soil-water-balance recharge during 2019–22, in inches per year 0.001 to 2.389 2.39 to 4.56

Boundary of the surficial extent of the rocks that contain the eastern part of the Arbuckle-Simpson aquifer (Oklahoma Water Resources Board, 2024a)

4.561 to 7.817 7.818 to 11.508 11.509 to 19.759 19.76 to 55.37

Figure 14. Spatially distributed mean annual recharge computed by using the Soil-Water-Balance code (Westenbroek and others, 2010) for the eastern Arbuckle-Simpson aquifer study area, south-central Oklahoma, 2019–22.

Hydrologic Data Comparison: Phase 1 to Phase 2 41 than the surrounding soil types overlying the Arbuckle and Simpson Groups that make up the eastern part of the Arbuckle-Simpson aquifer (fig. 14).

Groundwater Withdrawals and Water Use Permitted users of groundwater in Oklahoma are required by statute to report their water use annually to the OWRB (Oklahoma State Legislature, 2023d). The OWRB does not require permits for the following: use of water by a natural individual or by a family or household for household purposes, for farm and domestic animals up to the normal grazing capacity of the land whether or not the animals are actually owned by such natural individual or family, and for the irrigation of land not exceeding a total of three acres in area for the growing of gardens, orchards, and lawns. Domestic use also includes: (1) the use of water for agriculture purposes by natural individuals, (2) use of water for fire protection, and (3) the use of water by non-household entities for drinking water purposes, restroom use, and the watering of lawns, provided that the amount of groundwater used for any such purposes does not exceed five acre-feet per year. Pit dewatering is exempt from needing a permit unless the mine (pit) is overlying the Arbuckle-Simpson aquifer. Most groundwater wells currently (2024) completed in the eastern part of the Arbuckle-Simpson aquifer are primarily for domestic use, with agriculture as the second most common type of use. The depths of most wells completed in the eastern part of the Arbuckle-Simpson aquifer are less than 200 ft bls, and in general, wells completed in the part of the eastern part of the Arbuckle-Simpson aquifer contained in the Simpson Group tend to be shallower than those completed in the Arbuckle aquifer, where well depths can be as much as 800 ft bls.

Groundwater Withdrawals The amount of groundwater that can be appropriated in Oklahoma is tied to the amount of land the applicant either owns or leases and the equal proportionate share determined by the OWRB for the underlying aquifer (Oklahoma State Legislature, 2023b). These lands put toward the application are referred to as “dedicated lands” (fig. 1). Groundwater-use data are self-reported by the permitted groundwater user annually to the OWRB. Nine different beneficial groundwater-use types are regulated by the OWRB for groundwater permits: (1) irrigation, (2) public supply, (3) industrial, (4) power, (5) mining, (6) commercial, (7) recreation, fish, and wildlife, (8) agricultural, and (9) other (fig. 1). Power and commercial groundwater-use type was not included in this study’s results because of no reported use in that category. The amounts of groundwater used for recreation, fish, and wildlife, agriculture, and other have been combined into one category because of their relatively low combined use amount compared to the other uses. Public supply was the most reported beneficial

groundwater-use type during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, with the aquifer providing water for municipalities within the study area (fig. 15A; table 11; Mashburn and others, 2025). The mean annual reported groundwater use during 1967–2020 was 3,251 acre-feet. Permitted amounts per groundwater user were summed for each year (fig. 15B). Some permitted groundwater users did not report use each year, which could be because of not using their permitted allotment or they were not compliant with reporting requirements. For example, the City of Ada reported groundwater use of 4,179 and 5,094 acre-feet in 2011 and 2012, respectively, with little (less than 1,100 acre-feet) to no groundwater use reported during 2013–20. As described in Christenson and others (2011, p. 51), The large variation in reported groundwater use by the City of Ada is largely related to variation in discharge from Byrds Mill Spring, Ada’s primary water source. When discharge from Byrds Mill Spring is adequate to meet demand, the City of Ada meets that demand by diverting water from the spring and does not withdraw groundwater. Water diverted from Byrds Mill Spring is reported as surface-water use, and therefore, in years when the flow from Byrds Mill Spring is adequate to meet demand, Ada’s reported groundwater use is zero. When discharge from the spring is low, Ada supplements water from the spring by withdrawing groundwater from wells completed in the aquifer to preserve streamflow for downstream landowners.

Consumptive Water Use at Producing Mines Additional rules related to the withdrawal, use, and disposal of groundwater associated with producing mines provide a framework to protect groundwater in the Arbuckle-Simpson aquifer (Oklahoma State Legislature, 2023e). Based on these rules, the OWRB gathers data provided by the mining companies of monitoring and periodic reporting of groundwater disposition. Mines are required by the OWRB to submit either a management plan to monitor and quarterly and annual reports of water volumes. These management plans and reports include a water budget for the mine that describes anticipated water moving into and out of the mine site as stream and groundwater inflows and outflows (includes augmentation outflows to streams and the groundwater system), pit water, precipitation runoff, and evaporation. These water volumes are used by the OWRB to estimate the consumptive use of pit water. Water volume data from these management plans and reports were compiled for 2019–22 from the OWRB website (OWRB, 2024b) in February 2024. Each mine is required to report these data once every quarter, as well as a total annual water volume. Each mine is required to report the amount of precipitation that falls onto the land and flows

42 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

10,000

A Phase 1

EXPLANATION

9,000

Reported groundwater use, in acre-feet

Phase 2

Public supply Mining Industrial Irrigation Combined (recreation, fish, and wildlife; agriculture; and other)

8,000 7,000 6,000 5,000 4,000 3,000 2,000

1967 1968 1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 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 2012 2013 2014 2015 2016 2017 2018 2019 2020

1,000

Year

10,000

B Phase 1

Phase 2

Total permitted groundwater use, in acre-feet

9,000 8,000 7,000 6,000 5,000 4,000 3,000 2,000

1,000

Year Notes: Data from Mashburn and others (2025). Groundwater use data were only available through 2020 at the time this report was written.

Figure 15. A, Reported groundwater use by type and B, permitted groundwater use during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.

Hydrologic Data Comparison: Phase 1 to Phase 2 43 Table 11. Annual reported groundwater use during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma. [Values are shown in the reported precision and are in units of acre-feet; Power and commercial groundwater-use types not listed because of zero reported groundwater use; Data are from Mashburn and others (2025)]

Year

Combined (recreation, fish, and wildlife; agriculture; other)

Public supply

Mining

Industrial

Irrigation

Total

1967

921

287

894

2,142

1968

687

287

927

500

2,401

1969

650

287

1,009

533

2,479

1970

700

287

1,352

533

2,873

1971

760

287

1,028

667

2,742

1972

851

1,069

1,920

1973

817

287

1,304

2,408

1974

6,303

287

1,223

7,832

1975

882

459

1,165

2,573

1976

923

369

733

270

2,295

1977

6,920

369

180

7,469

1978

5,233

374

1,031

160

6,797

1979

5,850

383

1,646

123

8,003

1980

3,596

383

1,450

345

5,774

1981

1,166

661

1,433

107

3,367

1982

1,319

1,473

105

2,979

1983

1,493

828

1,473

293

4,087

1984

1,959

830

1,360

425

4,575

1985

1,666

878

1,277

308

4,129

1986

905

881

111

1,897

1987

789

881

241

1,912

1988

2,062

881

341

3,285

1989

1,900

881

180

2,962

1990

1,878

881

251

3,009

1991

1,905

881

2,793

1992

2,181

881

3,090

1993

2,093

881

242

3,274

1994

2,080

881

611

3,663

1995

1,991

881

506

3,471

1996

1,901

881

336

124

3,242

1997

1,988

842

599

184

3,614

1998

2,681

842

356

230

4,109

1999

2,411

842

348

127

3,729

2000

3,272

842

1,073

168

5,355

2001

2,682

842

1,077

231

4,832

2002

2,368

842

341

143

3,695

2003

5,921

842

551

7,398

2004

4,673

842

379

201

6,095

2005

2,259

842

3,170

2006

6,014

1,516

715

153

8,397

44 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 11. Annual reported groundwater use during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma.—Continued [Values are shown in the reported precision and are in units of acre-feet; Power and commercial groundwater-use types not listed because of zero reported groundwater use; Data are from Mashburn and others (2025)]

Year

Industrial

Irrigation

Combined (recreation, fish, and wildlife; agriculture; other)

Total

Public supply

Mining

2007

2,591

677

502

1,133

4,903

2008

3,951

939

691

464

6,044

2009

3,336

508

420

4,264

2010

2,390

296

2,743

2011

6,831

416

7,283

2012

7,733

7,873

2013

2,990

100

3,137

2014

3,495

134

3,672

2015

3,499

3,639

2016

2,688

156

2,955

2017

2,017

144

2,226

2018

2,111

200

2,374

2019

2,028

152

2,247

2020

1,910

118

2,082

over the land surface and subsequently drains into mine pits, as well as nonconsumptive water losses (including pit water returned to the land surface from which surface runoff flows into a mine pit). Some of the mines, are considered de minimis, that coincide with the location of the eastern part of the Arbuckle-Simpson aquifer have an exemption from having to report the measured quarterly or annual water volumes, but they are still required to submit a plan of anticipated volumes. De minimis is the taking, use or disposal of pit water in an amount less than five acre-feet per year (Oklahoma State Legislature, 2023b). For the purposes of this study, water volumes provided per mine in either a management plan or a quarterly or annual report were included in the estimated consumptive use. The consumptive use estimates do not distinguish between groundwater and surface water. Some reports appeared to be incomplete; however, it was beyond the scope of this report to resolve any apparent discrepancies in reported water volumes. Consumptive use water volumes were compiled from annual plans and reports for the 2019–22 period for eight mines (table 12). Of the 11 mines that submitted reports to the OWRB, 3 of them indicated that they had no water volume to report (OWRB, 2024b). Three of the remaining eight mines that submitted reports coincide with the surficial extent of the eastern part of the Arbuckle-Simpson aquifer (table 12). A negative consumptive water-use value indicates that there was no consumption of water by the mine and water was returned to the natural system through a variety of processes that exceeded the total volume of water withdrawn

from the producing mine pit (mine pit pumping), including natural evaporation from the pit, water evaporated during the drying of the mined material, water in the mined material transported from the mine, volume of water used for beneficial uses, pit water returned to a groundwater basin (groundwater augmentation), pit water returned to a definite stream during flow conditions that are less than or equal to 50-percent exceedance (stream augmentation) (fig. 7), and other losses such as pit groundwater returned to the land surface via runoff. The 50-percent exceedance is the median of mean daily flows for the period of record analyzed (Oklahoma State Legislature, 2023b). The USGS streamflow data are used by the OWRB to update the calculation of the 50-percent exceedance annually. Mines can offset the water pumped from the mine if stream augmentation occurs when the streamflow is less than or equal to the 50-percent exceedance. The sum of the water withdrawn from mine pits, sum of stream augmentation, and sum of groundwater augmentation are also reported for each year for the eight mines for which compiled water-use data were available (table 12). Water is discharged into streams from point sources by mines that have a National Pollutant Discharge Elimination System (NPDES) permit (EPA, 2024b). Eight mines located within the surficial extent of the eastern part of the Arbuckle-Simpson aquifer had an NPDES permit. Four of the eight mines reported discharge monitoring data for outflow discharges during 2019–23 (EPA, 2024b). The reported NPDES monthly mean of daily discharges ranged from 1.2 to

Water-Budget Comparison: Phase 1 to Phase 2 45 Table 12. Summary statistics of annual consumptive water-use estimates, and sum of water pumped from mine pits, water discharged to streams (stream augmentation), and water injected into the subsurface (groundwater augmentation) from producing mines in the Arbuckle-Simpson aquifer, south-central Oklahoma, 2019–22 (Oklahoma Water Resources Board, 2024b). [Consumptive water-use summary statistics are shown to the reported precision and are in units of acre-feet per year; shaded columns are those values reported as sums]

Number Period of summarized reporting mines1

Consumptive water-use estimates (in acre-feet per year) Minimum

Maximum

Mean

Median

Sum of consumptive water use Standard for period deviation

Sum of water Sum of pumped stream from augmentation mine pits for period

Sum of groundwater augmentation

2019

−2,714

165

−357

−7

965

−2,863

14,691

351

8,390

2020

−2,139

322

−274

642

−2,192

15,839

9,000

2021

−1,757

164

−260

798

−2,087

14,691

351

8,460

2022

−1,640

118

−235

589

−1,881

14,691

351

8,402

2019–22

−2,714

322

−281

748

−9,023

59,912

1,096

34,252

1Three of the eight mines are located in the eastern part of the Arbuckle-Simpson aquifer.

62 acre-feet per day during 2019–23. The reported NPDES monthly maximum of daily discharges ranged from 1.2 to 134 acre-feet per day during 2019–23.

Water-Budget Comparison: Phase 1 to Phase 2 As part of the Phase 1 studies, the USGS developed an aquifer water budget for the October 2003 to September 2008 period. The Phase 1 water budget was summarized from the calibrated numerical groundwater-flow model from Christenson and others (2011, table 20, page 75). The Phase 2 water budget was summarized by using the data from this study for a conceptual water budget for the 2018–22 calendar years because as of the writing of this report, a numerical model had not yet been developed for Phase 2 that could be used to assess the water budget more accurately. The 2023 calendar year was not included in the water budget because when the precipitation, air temperature, and reported groundwater withdrawals were compiled for this report, these data were only available through 2022. The Phase 1 and Phase 2 water budgets were compiled for the eastern part of the Arbuckle-Simpson aquifer. The components of the water budget for Phase 2 consisted of inflows of recharge and net change in groundwater storage and outflows of net streambed seepage and spring discharge, evapotranspiration and reported groundwater withdrawals (fig. 16B). Recharge used for the Phase 2 conceptual water budget was derived from the spatially distributed mean annual SWB-estimated recharge of 4.85 in/yr for the 2019–2022 period that was increased by 50 percent to better align with the recharge results from the Rorabaugh method. The SWB computations were done by

using data from 2019–22 because most of the wells used for the SWB analyses became operational in 2019. Net streambed seepage was estimated across the aquifer by using base flow calculated from the PART method for streamgages 07331300, 07331200, 07332390, and 07334428 for the 2019–21 period. These streamgages are the most downstream streamgages overlying and near the eastern part of the Arbuckle-Simpson aquifer for Pennington Creek, Mill Creek, Blue River, and Delaware Creek, respectively (fig. 1). An additional 10 percent of the calculated base flow from these streamgages was added to account for the remaining streams that emanate and flow across the aquifer without streamgages to monitor discharge. Ten percent was chosen because approximately 10 percent of the eastern part of the Arbuckle-Simpson aquifer area was ungaged. Saturated-zone evapotranspiration was estimated by using the area of wetlands (2,258 acres) from the National Wetlands Inventory (U.S. Fish and Wildlife Service, 2024) overlying the eastern part of the Arbuckle-Simpson aquifer extent and an estimate of 2 ft of evapotranspiration from the groundwater saturated zone likely occurring annually. White (1932), estimated annual saturated-zone evapotranspiration rates of 0.75–1.9 feet per year (ft/yr) for undisturbed salt grass cover in southwestern Utah, with a mean depth to water of 1–2 ft. Relative humidity and dewpoint temperature are comparatively low in southwestern Utah compared to southeastern Oklahoma (NCEI, 2023); however, precipitation is much higher in southeastern Oklahoma compared to southwestern Utah, which likely results in an overall higher annual rate of evapotranspiration for the study area compared to what White (1932) reported for the Utah study area. Smith and others (2021) and Rogers and others (2023) estimated saturated-zone evapotranspiration for the Salt Fork Red River aquifer and the reaches 3 and 4 of the Washita River aquifer to be 1.0 ft/yr and 1.33 ft/yr, respectively for the two aquifers. These two aquifers are in southwestern Oklahoma

46 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma where mean precipitation rates are lower than they are in southeastern Oklahoma. Because the Arbuckle-Simpson aquifer receives greater amounts of precipitation (NCEI, 2023) and has approximately similar temperatures when compared to areas overlying the Salt Fork Red River aquifer and reaches 3 and 4 of the Washita River aquifer, a saturated-zone evapotranspiration rate of 2.0 ft/yr was assumed for the study area. Reported groundwater use (groundwater withdrawals) was averaged annually for the 2018–20 period. The net change in groundwater storage was calculated by analyzing the groundwater levels in the study area for Phase 2 (2019–23) (fig. 11); the average decline in groundwater levels in the eastern part of the Arbuckle-Simpson aquifer was determined as approximately 3 ft/yr. A specific yield of 0.01 was reported by Christenson and others (2011) as the average specific yield of the eastern part of the Arbuckle-Simpson aquifer. To calculate the net change in groundwater storage, the 3-ft/yr change in groundwater levels was multiplied by the specific yield of 0.01 and then multiplied by the aquifer area. The two largest components of the water budget, recharge and net streambed seepage, were greater in Phase 2 than in Phase 1 by 74 percent and 74 percent, respectively. Evapotranspiration from the saturated zone was not

individually accounted for in the numerical water budget for Phase 1. Groundwater withdrawals in Phase 2 decreased by 60 percent from Phase 1 groundwater withdrawals. Groundwater storage in the water budget consists of flow that is sourced from the storage in the aquifer; therefore, a positive mean annual flow for groundwater storage indicates flow to the groundwater flow system came from storage, which results in a decrease in the aquifer storage. The net change in groundwater storage increased by approximately 837 percent (8,843 acre-feet per year) from Phase 1 to Phase 2, indicating a decrease in aquifer storage (decline in groundwater levels) in the Arbuckle-Simpson aquifer from Phase 1 to Phase 2 (fig. 16; table 13). Overall, the water budget for the eastern part of the Arbuckle-Simpson aquifer during Phase 2 appears to include more groundwater inflow, more groundwater outflow, and more groundwater flow from storage (decreased aquifer storage) than during Phase 1. This is apparent from the increase in precipitation, recharge, streamflow, and base flow and the decrease in groundwater levels. However, discharge from springs both increased and decreased at sites measured during the historical period and Phase 2. Outflows, such as groundwater withdrawals, were smaller in Phase 2 compared to Phase 1.

Pennington Creek near Reagan, Oklahoma. Photograph by Grant Graves.

Water-Budget Comparison: Phase 1 to Phase 2 47

300,000

A EXPLANATION Phase 1 numerical model water budget, October 2003 to September 2008

Mean annual flow, in acre-feet per year

200,000

100,000

1,056

115,104 –110,604

–5,568

Net streambed seepage

Well withdrawals

−100,000

−200,000

−300,000

Net change in groundwater storage

Recharge

Figure 16. Water budgets for the eastern part of the Arbuckle-Simpson aquifer during A, Phase 1 numerical model period (October 2003 to September 2008) and B, Phase 2 conceptual model period (2018–22 calendar years), south-central Oklahoma.

48 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

300,000

B EXPLANATION Phase 2 conceptual water budget, 2018−22

Mean annual flow, in acre-feet per year

200,000

100,000

9,899

200,040 −192,431

−2,340

−2,233

Net streambed seepage and spring discharge

Evapotranspiration

Well withdrawals (reported groundwater withdrawals)

−100,000

−200,000

−300,000

Net change in groundwater storage

Figure 16.—Continued

Recharge

Water-Budget Comparison: Phase 1 to Phase 2 49 Table 13. Phase 2 conceptual water budget for the eastern part of the Arbuckle-Simpson aquifer, south-central Oklahoma (2018–22). [acre-ft/yr, acre-feet per year; --, not quantified; in/yr, inch per year; ft/yr, foot per year; OWRB, Oklahoma Water Resources Board; NWI, National Wetlands Inventory; PART, hydrograph-separation method for determining base flow; ET, evapotranspiration; SWB, Soil-Water-Balance (Westenbroek and others, 2010); GW, groundwater]

Water-budget category Aquifer area, in acres

Mean annual flow (acre-ft/yr)

Percentage of water budget

329,963

Recharge, evapotranspiration, and streambed seepage are assumed to only occur in the unconfined part of the aquifer.

200,040

95.28%

4.85 in/yr, or 12 percent, of mean annual precipitation estimated by using the SWB code for 2019–22 period; increased by 50 percent to 7.28 in/yr.

9,899

4.72%

Mean decline in GW levels (2019–24 period) of 15 feet, or 3 ft/yr, and a specific yield of 0.01 multiplied by aquifer area.

Notes

Inflows Recharge

Net change in groundwater storage

Total inflow

209,939

100% Outflows

Net streambed seepage and spring discharge

192,431

97.7%

Estimated from PART base-flow data for the 2019–22 period.

Evapotranspiration

2,340

1.2%

From NWI wetlands area of 1,170 acres and 2 feet of ET for the 2018–22 period.

Well withdrawals (groundwater withdrawals)

2,233

1.1%

From OWRB reported water-use data for 2018–20.

Total outflow

197,004

100%

Discrepancy in outflows-inflows

12,935

50 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Future Studies and Monitoring Data To quantify water resources for a natural system and thus provide information that will help to address water resource management questions, the first step is to collect accurately measured water-quantity-related data. The scales (temporal and spatial) for which a water resource manager attempts to answer water management questions is the scale for which these quantity data should be measured. The time interval is an important consideration for data collection and will vary depending on whether the goal is to try to capture subdaily, daily, monthly, or annual effects on the water resources. In addition, the scale and scope of the data collected across a study area should be dependent on the scale of the questions being asked. This report contains compiled daily or subdaily measured quantities of precipitation, streamflow, springflow, and groundwater levels across the study area. However, reported groundwater withdrawals and water pumped from mine pits and discharges from producing mines presented in this report are compiled from self-reported or estimated quantities on monthly or annual timescales. Human activities that release water into these natural systems complicate analyses for hydrologists and water-resource managers when they are not measured. For example, stream augmentation that occurs from mines affects streamflow hydrographs and analysis of streamflow for determination of base flow (fig. 7). Additional analysis on quantifying these anthropogenic stream augmentations from natural discharges on hydrographs, obtaining discharge rates of releases to streams from the mines, or deploying a device that measures these discharges would be beneficial to future studies to fully analyze the effects of streamflow augmentation on streamflow (and potentially recharge to the aquifer). Future plans and studies by hydrologists and water resource managers to answer application-specific questions about the Arbuckle-Simpson aquifer could benefit from additional data collection, such as the installation of data collection sites for monitoring daily volumetric outflow (pumping and discharging) rates. The collection of daily volumetric outflow monitoring data could help to reduce the uncertainty in those data that were estimated in this report.

Summary Based primarily on data collected between 2003 and 2008, a series of comprehensive hydrologic studies of the Arbuckle-Simpson aquifer in south-central Oklahoma was published between 2003 and 2011. For this report, “Phase 1” refers to an initial 2003–08 data collection period, although for some analyses, data collected prior to 2003 were used to inform model development. Results from Phase 1 provided information necessary to perform groundwater-flow model simulations that, in addition to characterizing groundwater resources in the study area, helped inform the Oklahoma

Water Resources Board (OWRB) in their decisions regarding how much water could be withdrawn from the aquifer while maintaining flow to springs and streams. As part of the Phase 1 studies, an aquifer water budget was developed from a numerical model for the period 2003–08. Allocation of water from this aquifer was then established by the OWRB in 2013. Additional well-spacing rules were also established by the OWRB for sensitive sole source groundwater basins. To determine how the water budget for the eastern part of the Arbuckle-Simpson aquifer has changed over time, recently collected hydrologic data (2018–23) were compared to data collected during 2003–08. The analysis of changes in the aquifer water budget from 2003–08 to 2018–23 could help resource managers better understand changes in the overall balance of water in storage and potential effects to streamflow, changes in groundwater levels, and the effects of different water uses in the aquifer area on available water in both the eastern part of the Arbuckle-Simpson aquifer and streams overlying the eastern part of the Arbuckle-Simpson aquifer. This report documents the results of a study done by the U.S. Geological Survey (USGS), in cooperation with the OWRB and the Oka’ Institute, to document recently collected (2018–23) hydrologic data and assess water-budget changes for the eastern part of the Arbuckle-Simpson aquifer. The Arbuckle Mountains are composed of Proterozoicand Cambrian-aged igneous and metamorphic rocks overlain by sedimentary rocks that are Cambrian to Late Pennsylvanian in age. The geology of the Arbuckle Mountains is characterized by both macro- and meso-scale deformations, consisting of folded structures, large fault displacements, uplifts, and karstic features developing in their carbonate sedimentary rocks. Sinkholes, caves, springs, and other characteristic karst features are present throughout the Arbuckle Mountains. Because all these features affect the flow and availability of groundwater in the study area, the geologic framework of the Arbuckle Mountains is considered when assessing groundwater in the Arbuckle-Simpson aquifer. The Arbuckle Group is approximately 3,000 feet thick in most of the eastern part of the Arbuckle-Simpson aquifer study area but has been eroded away over parts of the Belton Anticline. The portion of the Arbuckle-Simpson aquifer contained in the Arbuckle Group is more productive than the portion contained in the Simpson Group because of its intercrystalline porosity and the numerous fractures, solution channels, and cavities it contains. The Simpson Group was deposited in the Middle to Late Ordovician and is the younger of the lithostratigraphic groups contained in the Arbuckle-Simpson aquifer. The Simpson Group is generally less than 1,000 feet thick in the eastern part of the Arbuckle-Simpson aquifer and is exposed at the surface in about one-third of the total aquifer area, typically along the edges of major anticlines and other structurally low areas. The mean annual precipitation for the 1895–2022 period was 37.97 inches per year (in/yr) for the eastern part of the Arbuckle-Simpson aquifer that extends across four counties in Oklahoma's south-central climate division, Climate Division 8.

Summary 51 The minimum temperature recorded was 16.4 degrees Fahrenheit in February 1899, and the maximum recorded temperature was 104.7 degrees Fahrenheit in August 2011, with an overall increase in temperature of 0.04 degree Fahrenheit per decade during the 1895–2022 period. Seven new USGS streamgages that monitor discharge were installed on streams flowing across the eastern part of the Arbuckle-Simpson aquifer as a part of Phase 2; in addition, five streamgages in the study area were used to monitor streamflow during Phase 1 and were still operational at the start of Phase 2. Streamflow is lowest in the summer (June– August) and winter (December–February), likely because of lower precipitation rates compared to the spring (April– May) and fall (September–November), as well as higher evapotranspiration rates in the summer. Base-flow separation was completed for three streamgages where streamflow data were collected for both Phase 1 and Phase 2. Base flow increased from Phase 1 to Phase 2 at all three streamgages. However, the base-flow portion of streamflow decreased from Phase 1 to Phase 2 at two of the three streamgages analyzed. One issue with attempting to compute the base-flow portion of streamflow is the influence of anthropogenic discharges upstream, such as stream augmentation from producing mines. These discharges affect streamflows measured and analyses of streamflows for interpretation of groundwater and surface-water interactions and base-flow analyses. The increases in the base-flow portion of streamflow and total streamflow during Phase 2 could be related to these upstream discharges. Net gains and losses in streamflow along stream segments were quantified by using discrete discharge measurements made during base-flow conditions, commonly referred to as synoptic base-flow (seepage-run) measurements. To ensure base-flow conditions were being captured, with as little runoff as possible, streamflow discharge was measured during January 24–31, 2022, and February 28–March 1, 2023. The 2022 seepage measurements indicated net gaining stream reaches along portions of Rock Creek, Mill Creek, Pennington Creek, and the Blue River. Upstream reaches of the Blue River were net losing, indicating net seepage losses from the stream into the Arbuckle-Simpson aquifer. The upper reaches of Pennington Creek and Mill Creek had no flow. Delaware Creek and Little Blue Creek (tributary to the Blue River) had losing segments. The 2023 seepage measurements indicated that more stream segments were gaining than during the 2022 measurements on Mill Creek, Pennington Creek, Blue River, Little Blue Creek, and Delaware Creek. In addition, streamflows computed at USGS streamgages in the study area were generally greater during the period when the 2023 measurements were made than during the period when the 2022 measurements were made. Discharge was continuously monitored at USGS streamgages at four major springs in the study area: Antelope Spring, unnamed Blue River spring, Byrds Mill Spring, and

Sheep Creek Spring. Spring discharge was generally lower in summer and winter when there is typically less precipitation compared to fall and spring, and evaporation losses reach their annual peak in the summer, which also causes spring discharge to decrease relatively more than during other seasons. For all seasons, spring discharges were generally highest during the spring because seasonal precipitation amounts are highest and because evapotranspiration rates in the spring are relatively low compared to those in the summer. Continuous spring discharge hydrographs from the Antelope Spring gage, Byrds Mill Spring gage, and Sheep Creek Spring gage were analyzed for the highest discharge periods during 2015–16 to identify flow regimes of this karst aquifer. As indicated by the recession curves at the highest discharge periods, Antelope Spring exhibits more conduit flow than during the other periods of recession, followed by greater portions of mixed and diffuse flow. Discharge data from the Byrds Mill and Sheep Creek Spring gages indicate that these springs, near the upper levels of the formation, undergo relatively more diffuse flow periods than Antelope Spring. Spring discharges were not measured and documented specifically for the Phase 1 studies, but historical spring discharges from the USGS National Water Information System database (1954–2017) were analyzed by the OWRB to identify which springs to include for the well-spacing rules for sensitive sole-source groundwater basins. Spring discharges for Phase 2 were measured during 2018–23 for comparison to historical spring discharges. Eleven of the 17 spring sites had a decrease in discharge from the historical period to Phase 2. The continuous groundwater monitoring network that was established for Phase 2 consisted of 23 wells, with 18 wells completed in the Arbuckle Group and 5 wells completed in the Simpson Group. Groundwater-level data from Phase 1 were compared to those collected during Phase 2 at five wells, with the results indicating relatively unchanged mean groundwater levels. The periods of lowest groundwater levels typically occurred during the summer and winter months, and the troughs in the groundwater-level hydrographs were generally shallower during Phase 2 than during Phase 1. Water levels in the study area during the summer and winter, particularly in the Arbuckle Group, appear to be generally decreasing during the Phase 2 period. These declining water levels seem to have been caused by decreasing precipitation, but they could also have been caused by increased water use or evapotranspiration. Groundwater-level data from 57 groundwater wells in 2022 and 56 wells in 2023 were used to create two potentiometric-surface maps over the main area of the eastern part of the Arbuckle-Simpson aquifer. The largest differences in water-level altitudes between 2022 and 2023 were in an area of four wells east of Pennington Creek. Even with localized differences between the two maps, general patterns remained similar in 2022 and 2023. Potentiometric

52 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma surfaces indicate that regional groundwater flow is toward the southeast, where streams and springs discharge at the aquifer boundary. Two methods were used in this study to estimate recharge: a recession-curve displacement method, or RORA method, was used to estimate recharge in a watershed upstream from three selected streamgages, and the Soil-Water-Balance (SWB) code was used to model spatially distributed recharge rates across the aquifer. The mean annual estimated recharge determined by using the RORA program for the eastern part of the Arbuckle-Simpson aquifer was 16.5 in/yr (or 43 percent of the 37.97 inches of mean annual precipitation) during 2018–22. Phase 2 mean annual recharge determined by using the RORA program was greater than Phase 1 mean annual recharge. For the Blue River near Connerville gage, the mean annual recharge increased by 98 percent from Phase 1 to Phase 2. For the Pennington Creek near Reagan gage, the mean annual recharge increased by 33 percent from Phase 1 to Phase 2. The same issue mentioned for base-flow analysis of streamflow also affects recharge estimates obtained from the RORA program. Upstream anthropogenic streamflow augmentation from producing mines affects recharge estimates obtained from the RORA program by increasing the part of the hydrograph that is interpreted by the RORA program as recharge to the aquifer. The SWB code was run to estimate the amount and spatial distribution of daily groundwater recharge to the eastern part of the Arbuckle-Simpson aquifer only for 2019–22. The mean annual SWB-estimated recharge for the eastern part of the Arbuckle-Simpson aquifer was 4.85 in/yr (or 13 percent of the 7.97 inches of mean annual precipitation) for the 2019–22 period. The annual SWB-estimated recharge for the eastern part of the Arbuckle-Simpson aquifer was 7.2 inches for 2019, 5.9 inches for 2020, 2.6 inches for 2021, and 3.6 inches for 2022. Nine different beneficial groundwater-use types are regulated by the OWRB for groundwater permits: (1) irrigation, (2) public supply, (3) industrial, (4) power, (5) mining, (6) commercial, (7) recreation, fish, and wildlife, (8) agricultural, and (9) other. Public supply was the most reported beneficial groundwater-use type during 1967–2020 for the eastern part of the Arbuckle-Simpson aquifer, with the aquifer providing water for municipalities within the study area. The mean annual reported groundwater use during 1967–2020 was 3,251 acre-feet. Management plans and reports submitted to the OWRB by mines for monitoring and periodic reporting of groundwater disposition include a water budget for the mine that describes anticipated water moving into and out of the mine site as stream and groundwater inflows and outflows (includes augmentation outflows to streams and the groundwater system), pit water, precipitation runoff, and evaporation. These water volumes are used by the OWRB to estimate the consumptive use of pit water. Water volume data from these management plans and reports were compiled for 2019–22 and summarized in this report. The sum of the water

withdrawn from mine pits, sum of stream augmentation, and sum of groundwater augmentation are also reported for each year for the eight mines for which compiled water-use data were available. As part of the Phase 1 studies, the USGS developed an aquifer water budget from a numerical model for the October 2003 to September 2008 period. The Phase 2 water budget was summarized by using the data in this report for a conceptual water budget for the 2018–22 calendar years because as of the writing of this report, a numerical model had not yet been developed for Phase 2 that could be used to assess the water budget more accurately. Overall, the water budget for the eastern part of the Arbuckle-Simpson aquifer during Phase 2 appears to include more groundwater inflow, more groundwater outflow, and more groundwater flow from storage (decreased aquifer storage) than during Phase 1. This is apparent from the increase in precipitation, recharge, streamflow, and base flow and the decrease in groundwater levels. However, discharge from springs both increased and decreased at sites measured during the historical period and Phase 2. Outflows, such as groundwater withdrawals, were smaller in Phase 2 compared to Phase 1. This report contains compiled daily or subdaily measured quantities of precipitation, streamflow, springflow, and groundwater levels across the study area. However, reported groundwater withdrawals and water pumped from mine pits and discharges from producing mines presented in this report are compiled from self-reported or estimated quantities on monthly or annual timescales. Human activities that release water into these natural systems complicate analyses for hydrologists and water-resource managers when they are not measured. Future plans and studies by hydrologists and water resource managers to answer application-specific questions about the Arbuckle-Simpson aquifer could benefit from additional data collection, such as the installation of data collection sites for monitoring daily volumetric outflow (pumping and discharging) rates. The collection of daily volumetric outflow monitoring data could help to reduce the uncertainty in those data that were estimated in this report.

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56 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Rahi, K., and Halihan, T., 2009, Estimating selected hydraulic parameters of the Arbuckle-Simpson aquifer from the analysis of naturally-induced stresses—Final report submitted to the Oklahoma Water Resources Board: Stillwater, Okla., Oklahoma State University, School of Geology, 48 p., accessed June 25, 2024, at https://www. owrb.ok.gov/studies/groundwater/arbuckle_simpson/ pdf/2009_Reports/Hydraulic_RahiHalihan/Estimating HydraulicParametersAnalysisNaturallyInducedStresses Arbuckle_RahiHallihan.pdf.

Sample, M.S., 2008, Characterization of the epikarst over the Hunton Anticline, Arbuckle-Simpson aquifer, Oklahoma: Stillwater, Okla., Oklahoma State University, M.S. thesis, 220 p., accessed June 25, 2024, at http://hdl.handle.net/ 20.500.14446/8052.

Rahi, K., and Halihan, T., 2012, Identifying aquifer type in fractured rock aquifers using harmonic analysis: Groundwater, v. 51, no. 1, p. 76–82, accessed June 25, 2024, at https://doi.org/10.1111/j.1745-6584.2012.00925.x.

Scheirer, D.S., and Hosford Scheirer, A., 2006, Gravity investigations of the Chickasaw National Recreation Area, south-central Oklahoma: U.S. Geological Survey Open-File Report 2006–1083, 40 p., accessed December 12, 2023, at https://pubs.usgs.gov/of/2006/1083/.

Ramachandran, K., Tapp, B., Rigsby, T., and Lewallen, E., 2012, Imaging of fault and fracture controls in the Arbuckle-Simpson aquifer, southern Oklahoma, USA, through electrical resistivity sounding and tomography methods: International Journal of Geophysics, v. 2012, 10 p., accessed June 25, 2024, at https://doi.org/10.1155/ 2012/184836. Rantz, S.E., and others, 1982, Measurement and computation of streamflow—Volume 1. Measurement of stage and discharge: U.S. Geological Survey Water-Supply Paper 2175, 284 p., accessed December 23, 2024, at https://doi.org/10.3133/wsp2175. Riley, M.E., 2004, Investigation of fault properties using electrical resistivity imaging: Stillwater, Okla., Oklahoma State University, M.S. thesis, 104 p., accessed June 25, 2024, at http://hdl.handle.net/20.500.14446/8049. Rogers, I.M.J., Smith, S.J., Gammill, N.C., Gillard, N.J., Lockmiller, K.A., Fetkovich, E.J., Correll, J.S., and Hussey, S.P., 2023, Hydrogeology and simulated groundwater availability in reaches 3 and 4 of the Washita River aquifer, southern Oklahoma, 1980–2017: U.S. Geological Survey Scientific Investigations Report 2023–5072, 83 p., accessed January 1, 2024, at https://doi.org/10.3133/sir20235072. Rorabaugh, M.I., 1964, Estimating changes in bank storage and ground-water contribution to streamflow: International Association of Scientific Hydrology, publication 63, p. 432–441, accessed June 25, 2024, at https://iahs.info/ uploads/dms/063044.pdf. Rutledge, A.T., 1998, Computer programs for describing the recession of ground-water discharge and for estimating mean ground-water recharge and discharge from streamflow records—Update: U.S. Geological Survey Water-Resources Investigations Report 98–4148, 43 p., accessed June 25, 2024, at https://doi.org/10.3133/wri984148.

Sauer, V.B., and Turnipseed, D.P., 2010, Stage measurement at gaging stations: U.S. Geological Survey Techniques and Methods book 3, chap. A7, 45 p., accessed December 23, 2024, at https://doi.org/10.3133/tm3A7.

Seilheimer, T.S., and Fisher, W.L., 2008, Instream flow assessment of streams draining the Arbuckle-Simpson aquifer—Final report submitted to the Oklahoma Water Resources Board: Stillwater, Okla., Oklahoma State University, 49 p., accessed December 12, 2023, at https://www.owrb.ok.gov/studies/groundwater/arbuckle_ simpson/pdf/Arbuckle-SimpsonInstreamFlow.pdf. Sharp, J.M., Jr., 2024, A glossary of hydrogeology: Guelph, Ontario, Canada, The Groundwater Project, 211 p., accessed September 9, 2024, at https://doi.org/10.21083/978-1- 77470-079-2. Smith, D.V., Deszcz-Pan, M., and Smith, B.D., 2009, Depth section imaging for portions of an airborne geophysical survey of the Hunton Anticline, south-central Oklahoma: Final administrative report to the Oklahoma Water Resources Board in fulfillment of the cooperative agreement #08C7OK002032407, 38 p., accessed December 12, 2023, at https://www.owrb.ok.gov/studies/groundwater/arbuckle_ simpson/pdf/2009_Reports/DepthSectionImagingAirborne GeophysicalSurveyHuntonAnticline_SmithDeszczPan Smith.pdf. Smith, S.J., Ellis, J.H., Paizis, N.C., Becker, C.J., Wagner, D.L., Correll, J.S., and Hernandez, R.J., 2021, Hydrogeology and model-simulated groundwater availability in the Salt Fork Red River aquifer, southwestern Oklahoma, 1980–2015: U.S. Geological Survey Scientific Investigations Report 2021–5003, 85 p., accessed January 1, 2024, at https://doi.org/10.3133/sir20215003. Tarhule, A., 2009, Hydroclimatic reconstruction of the Arbuckle-Simpson aquifer using tree rings—Final report submitted to the Oklahoma Water Resources Board: University of Oklahoma, Department of Geography, 72 p., accessed December 12, 2023, at https://oklahoma.gov/ content/dam/ok/en/owrb/documents/science-and-research/ hydrologic-investigations/arbuckle-simpson-tree-ring- study.pdf.

References Cited 57 Thornthwaite, C.W., and Mather, J.R., 1957, Instructions and tables for computing potential evapotranspiration and the water balance: Centerton, N.J., Laboratory of Climatology, Publications in Climatology, v. 10, no. 3, p. 185–311.

U.S. Geological Survey [USGS], 2015, National Elevation Dataset (NED) 1/3 arc-second DEM: U.S. Geological Survey database, accessed September 21, 2015, at https:// apps.nationalmap.gov/downloader/#/.

Thornton, M.M., Shrestha, R., Wei, Y., Thornton, P.E., Kao, S-C., and Wilson, B.E., 2024, Daymet—Daily surface weather data on a 1-km grid for North America, version 4 R1: Oak Ridge National Laboratory Distributed Active Archive Center (ORNL DAAC) for Biogeochemical Dynamics digital data, accessed January 31, 2024, at https://doi.org/10.3334/ORNLDAAC/2129.

U.S. Geological Survey [USGS], 2023, USGS National Hydrography Dataset: U.S. Geological Survey database, accessed December 2024, at https://www.usgs.gov/national- hydrography/national-hydrography-dataset.

Turnipseed, D.P., and Sauer, V.B., 2010, Discharge measurements at gaging stations: U.S. Geological Survey Techniques and Methods, book 3, chap. A8, 87 p., accessed January 20, 2024, at https://doi.org/10.3133/tm3A8. U.S. Board on Geographic Names, 2024, Domestic names: U.S. Geological Survey web page, accessed June 18, 2024, at https://www.usgs.gov/us-board-on-geographic-names/ domestic-names. U.S. Department of Agriculture, 2024, Gridded Soil Survey Geographic (gSSURGO) database for the conterminous United States: U.S. Department of Agriculture, Natural Resources Conservation Service, accessed June 24, 2024, at https://gdg.sc.egov.usda.gov/GDGHome_ DirectDownLoad.aspx. U.S. Environmental Protection Agency [EPA], 1989, Arbuckle-Simpson aquifer of south central Oklahoma sole source aquifer—Final determination: Federal Register, v. 54, no. 184, p. 39230–39232, accessed December 5, 2024, at https://archive.org/details/sim_federal-register- find_1989-09-25_54_184/page/39230/mode/2up. U.S. Environmental Protection Agency [EPA], 2024a, Sole source aquifers for drinking water, accessed August 19, 2024, at https://www.epa.gov/dwssa/overview-drinking- water-sole-source-aquifer-program. U.S. Environmental Protection Agency [EPA], 2024b, Integrated Compliance Information System (ICIS)— National Pollutant Discharge Elimination System (NPDES) Permit Limit and Discharge Monitoring Report (DMR) datasets: U.S. Environmental Protection Agency database, accessed January 15, 2024, at https://echo.epa.gov/tools/ data-downloads/icis-npdes-dmr-and-limit-data-set. U.S. Fish and Wildlife Service, 2024, National Wetland Inventory, wetlands dataset: U.S. Fish and Wildlife Service web page, accessed June 24, 2024, at https://www.fws.gov/ program/national-wetlands-inventory/metadata.

U.S. Geological Survey [USGS], 2024a, USGS water data for the Nation: U.S. Geological Survey National Water Information System database, accessed January 2024, at https://doi.org/10.5066/F7P55KJN. [Oklahoma water data directly accessible at https://waterdata.usgs.gov/ok/nwis.] U.S. Geological Survey [USGS], 2024b, National geologic map database (Geolex): U.S. Geological Survey database, accessed April 15, 2024, at https://ngmdb.usgs.gov/ Geolex/search. Vieux, B.E., and Moreno, M.A., 2008, Arbuckle-Simpson hydrology study—Distributed water resources assessment— Final report submitted to the Oklahoma Water Resources Board: Norman, Okla., University of Oklahoma, School of Civil Engineering and Environmental Science, 44 p., 11 app., accessed June 24, 2024, at https://www.owrb.ok. gov/studies/groundwater/arbuckle_simpson/pdf/2009_ Reports/DistributedWaterResourcesAssessmentArbuckle_ VieuxMorenoOWRB.pdf. Westenbroek, S.M., Kelson, V.A., Dripps, W.R., Hunt, R.J., and Bradbury, K.R., 2010, SWB—A modified Thornthwaite-Mather Soil-Water-Balance code for estimating groundwater recharge: U.S. Geological Survey Techniques and Methods, book 6, chap. A31, 60 p., accessed January 15, 2024, at https://doi.org/ 10.3133/tm6A31. White, W.N., 1932, A method of estimating ground-water supplies based on discharge by plants and evaporation from soil—Results of investigations in Escalante Valley, Utah: U.S. Geological Survey Water Supply Paper 659–A, 105 p., accessed August 20, 2024, at https://doi.org/ 10.3133/wsp659A. Winter, T.C., Harvey, J.W., Franke, O.L., and Alley, W.M., 1998, Ground water and surface water—A single resource: U.S. Geological Survey Circular 1139, accessed May 31, 2024, at https://doi.org/10.3133/cir1139. Young, R.A., Kennedy, B., and Russian, C., 2009, Analysis of seismic reflection data from the Hunton Anticline—Final report to the Oklahoma Water Resources Board: Oklahoma Water Resources Board, 13 p., accessed June 24, 2024, at https://www.owrb.ok.gov/studies/groundwater/arbuckle_ simpson/pdf/2009_Reports/AnalysisSeismicReflection DataHuntonAnticline_Young.pdf.

58 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

Appendix 1. Spring Discharge Measured in the Arbuckle-Simpson Aquifer Table 1–1. Springs with discharge greater than 50 gallons per minute based on historical data available in USGS NWIS database (USGS, 2024a), with springs having discharge greater than 500 gallons per minute that emanate from the Arbuckle-Simpson aquifer designated, a sensitive sole source groundwater basin, that are included in the well-spacing provisions established by the OWRB (Oklahoma State Legislature, 2023c). [USGS, U.S. Geological Survey; NWIS, USGS National Water Information System database; >, greater than; gal/min, gallons per minute. Springs listed are for the entire Arbuckle-Simpson aquifer across the western, central, and eastern parts]

Latitude, in decimal degrees

Longitude, in decimal degrees

07329849

34.504444

−96.941111

Antelope Spring

Yes

07329880

34.458900

−96.941400

Lowrance Springs

Yes

07334200

34.594534

−96.665563

Byrds Mill Spring

Yes

342035096554101

34.343148

−96.928345

Buck Irving Spring

Yes

342147096393901

34.363148

−96.661115

Three Springs

Yes

342148096394001

34.363426

−96.661392

Three Springs

Yes

342150096284002

34.363981

−96.478055

Seven Springs 2

Yes

342342096464801

34.394889

−96.781056

Gray Spring

Yes

342342097134701

34.395088

−97.230019

Unnamed spring

Yes

342342097135501

34.395088

−97.232241

Unnamed spring

Yes

342353097045501

34.398145

−97.082239

Unnamed spring

Yes

342411096350101

34.403148

−96.583891

Deadmans Spring

Yes

342511097064501

34.419667

−97.111917

Devils Bathtub Spring

Yes

342517096453401

34.420322

−96.759006

Unnamed spring

Yes

342613096514701

34.437036

−96.863344

Colvert Spring

Yes

342634097160001

34.442865

−97.266965

Unnamed spring

Yes

342639097160001

34.444254

−97.266965

Unnamed spring

Yes

342712096373701

34.453425

−96.627226

Cummins Spring

Yes

342712096374101

34.453425

−96.628337

Unnamed spring

Yes

342726096400601

34.457389

−96.669417

Nelson Spring (Washington Spring)

Yes

342732096432201

34.458981

−96.723062

Gregor Spring

Yes

342738096401401

34.460647

−96.670839

Unnamed spring

Yes

342818097170501

34.471753

−97.285021

Unnamed spring

Yes

07329847

34.502700

−96.939300

Buffalo Spring

341540096485101

34.261205

−96.814451

Daube Spring

341638096502301

34.277316

−96.840008

Unnamed spring

341718096515802

34.288427

−96.866398

Webb Spring

341719096520801

34.288704

−96.869175

Unnamed spring

341927096541901

34.324259

−96.905566

Chapman Spring

341933096535201

34.325926

−96.898066

Tired Spring

341958096354301

34.332871

−96.595557

Desperado Spring

342054096514501

34.348426

−96.862787

South Spring

342108096553801

34.352314

−96.927512

Blue Hole Spring

342116096394601

34.354537

−96.663059

Wolf Spring

342216096314001

34.379694

−96.526972

Viola Spring

342218096411301

34.371760

−96.687227

Smith Spring

USGS station number

Spring short name

Discharge >500 gal/min?

Appendix 1. Spring Discharge Measured in the Arbuckle-Simpson Aquifer 59 Table 1–1. Springs with discharge greater than 50 gallons per minute based on historical data available in USGS NWIS database (USGS, 2024a), with springs having discharge greater than 500 gallons per minute that emanate from the Arbuckle-Simpson aquifer designated, a sensitive sole source groundwater basin, that are included in the well-spacing provisions established by the OWRB (Oklahoma State Legislature, 2023c).—Continued [USGS, U.S. Geological Survey; NWIS, USGS National Water Information System database; >, greater than; gal/min, gallons per minute. Springs listed are for the entire Arbuckle-Simpson aquifer across the western, central, and eastern parts]

Latitude, in decimal degrees

Longitude, in decimal degrees

342231096300901

34.375370

−96.502777

Unnamed spring

342232096561901

34.375647

−96.938902

Williams Spring

342233096444501

34.375333

−96.746972

Caldwell Spring

342246097143601

34.379533

−97.243630

Unnamed spring

342247097143301

34.379811

−97.242797

Unnamed spring

342253097165801

34.381477

−97.283075

Cold Spring

342254096425501

34.382389

−96.715389

Spring Creek Spring

342318096325401

34.388426

−96.548612

Rutherford Spring

342335096462501

34.392861

−96.774000

Trent Spring

342337097134801

34.393700

−97.230297

Unnamed spring

342414096364701

34.404056

−96.613278

Diamond Spring

342421097065401

34.405923

−97.115295

Unnamed spring

342428096444301

34.407870

−96.741951

Unnamed spring

342505097094401

34.418144

−97.162518

Unnamed spring

342517096453401

34.420322

−96.759006

Bridge Spring

342537096454701

34.426608

−96.763375

Pilot Spring

342613096521101

34.437036

−96.870011

Colvert Spring

342628097163001

34.441198

−97.275298

Unnamed spring

342634097104401

34.442866

−97.179186

Unnamed spring

342718096380401

34.454972

−96.634444

Anderson Spring

342724096400202

34.456759

−96.667505

Unnamed spring

342726096380001

34.457314

−96.633615

Inslee Spring

342727096401301

34.457592

−96.670561

Unnamed spring

342730096562701

34.458424

−96.941126

Lowrance Spring 2

342732096395801

34.458981

−96.666394

Shadowfax Spring

342732096400601

34.458981

−96.668616

Bilbo Spring

342732096402301

34.458981

−96.673339

Tisdell Spring

342757097195501

34.465919

−97.332244

Unnamed spring

342819097123301

34.472031

−97.209464

Boiling Spring

342837097193301

34.477030

−97.326133

Pole Spring

342908096373701

34.457333

−96.669472

Poe Spring

342911096373701

34.486481

−96.627227

Willis Spring

343114096332701

34.520647

−96.557781

Coffee Pot Spring

343114096353101

34.520500

−96.607806

Cave Spring

343241096360201

34.544750

−96.600833

Canyon Spring

343247097181901

34.481197

−97.308077

Five Mile Spring

343422096385101

34.572778

−96.647500

Sheep Creek Spring

343606096401301

34.601756

−96.670563

Unnamed spring

USGS station number

Spring short name

Discharge >500 gal/min?

60 Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma Table 1–2. Additional springs documented and discharge measured for Phase 2 (2018–23), south-central Oklahoma. [USGS, U.S. Geological Survey; ft3/s, cubic foot per second. Dates are in year-month-day format. Measurement ratings: excellent, discharge was within 2 percent of actual discharge; good, measured discharge within 5 percent of the actual discharge; fair, measured discharge within 10 percent of the actual discharge; poor and unspecified, measured discharge assumed to be within 8 percent of actual flow (Turnipseed and Sauer, 2010)]

USGS station number (USGS, 2024a)

Latitude, in decimal degrees

Longitude, in decimal degrees

Date measured

Discharge, in ft3/s

342216096314001

34.379694

−96.526972

2018-03-23

0.19

Poor

Viola Spring

342216096314001

34.379694

−96.526972

2018-06-14

0.28

Good

Viola Spring

342233096444501

34.375333

−96.746972

2018-04-20

0.17

Fair

Caldwell Spring

342233096444501

34.375333

−96.746972

2018-06-13

0.02

Poor

Caldwell Spring

342254096425501

34.382389

−96.715389

2018-03-26

0.35

Poor

Spring Creek Spring

342254096425501

34.382389

−96.715389

2018-06-14

1.49

Fair

Spring Creek Spring

342254096425501

34.382389

−96.715389

2022-09-12

7.98

Good

Spring Creek Spring

342335096462501

34.392861

−96.774

2018-04-20

1.03

Fair

Trent Spring

342335096462501

34.392861

−96.774

2018-06-13

0.35

Fair

Trent Spring

342342096464801

34.394889

−96.781056

2018-04-20

0.34

Fair

Gray Spring

342342096464801

34.394889

−96.781056

2018-06-28

0.26

Poor

Gray Spring

342414096364701

34.404056

−96.613278

2018-03-23

0.42

Fair

Diamond Spring

342414096364701

34.404056

−96.613278

2018-06-13

0.53

Fair

Diamond Spring

342511097064501

34.419667

−97.111917

2018-03-22

1.39

Poor

Devils Bathtub Spring

342511097064501

34.419667

−97.111917

2018-06-12

1.17

Fair

Devils Bathtub Spring

342518097064501

34.421917

−97.112778

2018-03-21

0.506

Fair

unnamed

342522097101201

34.422778

−97.170083

2018-03-21

0.0033

Fair

unnamed

342524097084701

34.423194

−97.1465

2018-06-12

0.05

Fair

unnamed

342524097084701

34.423194

−97.1465

2018-03-21

0.13

Fair

unnamed

342533097085401

34.425806

−97.14825

2018-03-21

0.0222

Fair

unnamed

342533097085401

34.425806

−97.14825

2018-06-12

0.019

Fair

unnamed

342614097114001

34.437333

−97.194528

2018-06-12

0.09

Fair

unnamed

342614097114001

34.437333

−97.194528

2018-03-21

0.21

Poor

unnamed

342718096380401

34.454972

−96.634444

2018-06-13

0.91

Fair

Anderson Spring

342718096380401

34.454972

−96.634444

2018-03-26

0.95

Fair

Anderson Spring

342718096380401

34.454972

−96.634444

2022-09-13

0.56

Fair

Anderson Spring

342718096380401

34.454972

−96.634444

2023-09-19

0.54

Fair

Anderson Spring

343007096581601

34.502

−96.9712

2018-04-03

0.19

Fair

unnamed

343007096581601

34.502

−96.9712

2018-06-12

0.11

Fair

unnamed

343012096581301

34.5028

−96.9702

2018-03-22

0.0294

Fair

unnamed

343012096581301

34.5028

−96.9702

2018-06-12

0.031

Fair

unnamed

343114096353101

34.5205

−96.607806

2018-03-26

0.01

Poor

Cave Spring

343241096360201

34.54475

−96.600833

2018-03-23

0.49

Fair

Canyon Spring

343241096360201

34.54475

−96.600833

2018-06-13

0.60

Fair

Canyon Spring

343418096384201

34.57175

−96.645083

2018-03-23

2.14

Fair

unnamed

343418096384201

34.57175

−96.645083

2018-06-14

1.89

Good

unnamed

343422096385101

34.572778

−96.6475

2018-03-23

3.43

Good

Sheep Creek Spring

343422096385101

34.572778

−96.6475

2018-06-07

3.55

Fair

Sheep Creek Spring

342722096395501

34.456314

−96.665522

2023-08-31

3.47

Good

unnamed

342722096395501

34.456314

−96.665522

2023-09-19

3.06

Fair

unnamed

Measurement rating

Spring short name

Appendix 1. Spring Discharge Measured in the Arbuckle-Simpson Aquifer 61 Table 1–2. Additional springs documented and discharge measured for Phase 2 (2018–23), south-central Oklahoma.—Continued [USGS, U.S. Geological Survey; ft3/s, cubic foot per second. Dates are in year-month-day format. Measurement ratings: excellent, discharge was within 2 percent of actual discharge; good, measured discharge within 5 percent of the actual discharge; fair, measured discharge within 10 percent of the actual discharge; poor and unspecified, measured discharge assumed to be within 8 percent of actual flow (Turnipseed and Sauer, 2010)]

USGS station number (USGS, 2024a)

Latitude, in decimal degrees

Longitude, in decimal degrees

Date measured

Discharge, in ft3/s

342723096395701

34.456464

−96.666072

2023-08-31

2.77

Fair

unnamed

342723096395801

34.456433

−96.666183

2023-08-31

1.52

Fair

unnamed

342247096425101

34.379861

−96.714253

2023-09-19

5.10

Good

unnamed

342725096400701

34.457069

−96.668692

2023-08-31

1.46

Fair

unnamed

342725096400701

34.457069

−96.668692

2023-09-19

2.06

Fair

unnamed

342725096400801

34.4571

−96.669119

2023-09-01

4.34

Fair

unnamed

342725096400801

34.4571

−96.669119

2023-09-19

3.26

Good

unnamed

342726096395501

34.457422

−96.665547

2023-09-01

0.95

Poor

unnamed

342726096395501

34.457422

−96.665547

2023-09-19

1.11

Poor

unnamed

342726096400602

34.457344

−96.668511

2023-08-31

0.06

Poor

unnamed

342726096400602

34.457344

−96.668511

2023-09-19

0.04

Poor

unnamed

342726096400902

34.457306

−96.669325

2019-09-19

3.13

Fair

unnamed

342726096400902

34.457306

−96.669325

2023-09-28

3.32

Fair

unnamed

342726096400903

34.457253

−96.669231

2019-09-19

3.13

Good

unnamed

342726096400903

34.457253

−96.669231

2023-09-01

2.86

Good

unnamed

342726096401001

34.457325

−96.669522

2023-09-01

0.07

Poor

unnamed

342726096401001

34.457325

−96.669522

2023-09-19

0.14

Poor

unnamed

342911096373701

34.486481

−96.627227

2022-09-12

1.48

Poor

Willis Spring

342911096373701

34.486481

−96.627227

2023-09-19

1.91

Poor

Willis Spring

Measurement rating

Spring short name

For more information about this publication, contact Director, Oklahoma-Texas Water Science Center U.S. Geological Survey 1505 Ferguson Lane Austin, TX 78754–4501 For additional information, visit https://www.usgs.gov/centers/ot-water Publishing support provided by Lafayette Publishing Service Center

Mashburn and others—Comparison of Hydrologic Data and Water Budgets, Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma—SIR 2025–5011

ISSN 2328-0328 (online) https://doi.org/10.3133/sir20255011

Comparison of Hydrologic Data and Water Budgets Between 2003–08 and 2018–23 for the Eastern Part of the Arbuckle-Simpson Aquifer, South-Central Oklahoma

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