Analysis of Environmental Setting, Surface-Water and 

Groundwater Data, and Data Gaps for the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, Through 2011

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2013–5010

Prepared in cooperation with the Citizen Potawatomi Nation

Analysis of Environmental Setting, Surface-Water and 

Groundwater Data, and Data Gaps for the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, Through 2011
Cover:

Left, Water tower located in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Shawnee, 

Oklahoma (photograph by Michael Dotson, Citizen Potawatomi Nation).

Right, Pond at the Grand Casino, Citizen Potawatomi Nation Tribal Jurisdictional Area, Shawnee, 

Oklahoma (photograph by Richard Kunze, Director of Public Works, Citizen Potawatomi Nation).
Analysis of Environmental Setting, SurfaceWater and Groundwater Data, and Data 

Gaps for the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, 

Through 2011

By William J. Andrews, Christopher R. Harich, S. Jerrod Smith, Jason M. Lewis, 

Molly J. Shivers, Christian H. Seger, and Carol J. Becker

Prepared in cooperation with the Citizen Potawatomi Nation

Scientific Investigations Report 2013–5010

U.S. Department of the Interior

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

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

This and other USGS information products are available at http://store.usgs.gov/

U.S. Geological Survey

Box 25286, Denver Federal Center

Denver, CO 80225

To learn about the USGS and its information products visit http://www.usgs.gov/

1-888-ASK-USGS

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Andrews, W.J., Harich, C.R., Smith, S.J., Lewis, J.M., Shivers, M.J., Seger, C.H., and Becker, C.J., 2013, Analysis of 

environmental setting, surface-water and groundwater data, and data gaps for the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, through 2011: U.S. Geological Survey Scientific Investigations Report 2013–5010, 

102 p., http://pubs.usgs.gov/sir/2013/5010/. 
Acknowledgments

The authors thank staff of the Citizen Potawatomi Nation for providing data and support 

for this report. The authors also thank staff of the U.S. Geological Survey, Oklahoma Water 

Resources Board, Oklahoma Department of Environmental Quality, Oklahoma Conservation 

Commission, the Kickapoo Tribe of Oklahoma, the Association of Central Oklahoma 

Governments, the Oklahoma State Health Department, and the U.S. Department of Energy 

for data derived from sampling of water resources in and near the Citizen Potawatomi Nation 

Tribal Jurisdictional Area.

v

Contents

Acknowledgments .......................................................................................................................................iii

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

Introduction ....................................................................................................................................................1

Purpose and Scope ......................................................................................................................................2

Location of the Study Area ..........................................................................................................................2

Methods of Analysis .....................................................................................................................................2

Selection of Climatic and Geographic Data ....................................................................................2

Selection of Streamflow Data ............................................................................................................2

Selection of Groundwater Data .........................................................................................................2

Selection of Water-Quality Data ........................................................................................................4

Estimation of Water Use .....................................................................................................................4

Analysis of Climatic and Geographic Data ......................................................................................5

Analysis of Hydrologic Data ...............................................................................................................5

Surface Water .............................................................................................................................5

Groundwater ................................................................................................................................6

Analysis of Water-Quality Data .........................................................................................................6

Surface Water .............................................................................................................................6

Groundwater ................................................................................................................................6

Quality Assurance .......................................................................................................................7

Evaluation of Water Use ..............................................................................................................................7

Summary of Climatic and Geographic Data .............................................................................................9

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

Physiography ........................................................................................................................................9

Soils ........................................................................................................................................................9

Geology ................................................................................................................................................10

Land Cover ..........................................................................................................................................13

Evaluation of Hydrologic Data ..................................................................................................................13

Surface Water ....................................................................................................................................13

Seasonality of Streamflow ......................................................................................................13

Magnitudes and Frequencies of Floods ................................................................................15

Low-Flow Characteristics .......................................................................................................16

Long-Term Trends .....................................................................................................................21

Groundwater .......................................................................................................................................23

Evaluation of Water-Quality Data .............................................................................................................25

Surface-Water Quality ......................................................................................................................25

Water Properties .......................................................................................................................25

Major Ions ..................................................................................................................................34

Nutrients .....................................................................................................................................34

Metals .........................................................................................................................................39

Fecal-Indicator Bacteria .........................................................................................................39

Quality Assurance .....................................................................................................................42

Groundwater Quality .........................................................................................................................42

Water Properties .......................................................................................................................42
vi

Major Ions ..................................................................................................................................44

Nutrients .....................................................................................................................................49

Metals .........................................................................................................................................49

Quality Assurance .....................................................................................................................52

Data Gaps .....................................................................................................................................................55

Summary .......................................................................................................................................................56

References Cited .........................................................................................................................................57

Glossary ........................................................................................................................................................62

Appendixes

1. Summary statistics of selected surface-water-quality data collected by the 

U.S. Geological Survey in or near the Citizen Potawatomi Tribal Jurisdictional 

Area, Oklahoma, 1985 through 2011 ........................................................................................65

2. Summary statistics of selected surface-water-quality data collected by the 

Citizen Potawatomi Nation, Oklahoma, 2009 through 2011 .................................................69

3. Summary statistics of surface-water-quality data collected by the Oklahoma 

Department of Environmental Quality in or near the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, 2003 ...........................................................................72

4. Summary statistics of surface-water-quality data collected by the Kickapoo Tribe 

of Oklahoma in or near the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, 2009 through 2011 ..................................................................................................73

5. Summary statistics of surface-water-quality data collected by the Oklahoma 

Water Resources Board in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1998 through 2005 ..............................................................75

6. Summary statistics of surface-water-quality data collected by the Oklahoma 

Corporation Commission in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1999 through 2002 ..............................................................93

7. Summary statistics of blank samples associated with surface-water-quality 

samples, by agency, collected in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1999 through 2011 ..............................................................96

8. Summary statistics of replicate surface-water-quality samples, by agency, 

collected in or near the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, 1988 through 2011 ..................................................................................................98

9. Summary statistics of groundwater-quality data collected in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, 1943–2005 .................................................99

Figures

1. Map showing location of the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, and locations of selected long-term streamflow-gaging stations 

and weather stations in and near that area ............................................................................3

2. Pie diagram showing estimated percentages and amounts of groundwater and 

surface water used in the Citizen Potawatomi Nation Tribal Jurisdictional Area 

by use type in Oklahoma, 2005 ...................................................................................................9

3. Graph showing annual precipitation and mean annual temperature at selected 

weather stations in or near the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, 1965 through 2010 ........................................................................................10

4. Shaded relief map of the land surface of the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma ................................................................................................11
vii

5. Map showing soil associations in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma ................................................................................................12

6. Map showing land cover in the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, 2006 ................................................................................................................14

7. Pie diagram showing percentages of land cover in the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, 2006 ..............................................................15

8. Graph showing monthly mean streamflow at four long-term streamflow-gaging 

stations in or near the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, October 1985 through September 2011 ..............................................................16

9. Graph showing monthly maximum, mean, and minimum streamflow at four 

long-term streamflow-gaging stations in or near the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, October 1985 through September 2011 ...............17

10. Boxplots showing distributions of streamflow by season at four long-term 

streamflow-gaging stations in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, October 1985 through September 2011 ..........................18

11. Graphs showing recurrence intervals and exceedance probabilities of selected 

streamflows at four long-term streamflow-gaging stations in and near the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 through 2010 ................19

12. Graphs showing recurrence intervals of low-flow streamflows by duration 

for four long-term streamflow-gaging stations in or near the Citizen Potawatomi 

Tribal Jurisdictional Area, Oklahoma .....................................................................................20

13. Graph showing mean annual streamflow at four long-term streamflow-gaging 

stations in and near the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, October 1985 through September 2011 ..............................................................21

14. Graphs showing annual peak flows and LOESS trend lines for selected periods 

at four long-term streamflow-gaging stations in or near the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, 1985 through 2010 ......................................22

15. Map showing principal aquifers and locations of 460 wells having depth-to-water 

measurements collected by the U.S. Geological Survey in the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, as of 2011 ....................................................24

16. Map showing locations of selected surface-water-quality sampling sites in and 

near the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma .....................26

17. Boxplots showing distribution of dissolved oxygen concentration in surfacewater samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, 1985 through 2011 ........................................................................................29

18. Map showing locations of National Pollutant Discharge Elimination System 

permit locations in and near the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, 2012 ................................................................................................................30

19. Graphs showing water-quality data from continuous monitor at the North 

Canadian River near Harrah, Oklahoma, streamflow-gaging station, October 2007 

through September 2011 ...........................................................................................................31

20. Boxplots showing distribution of pH in surface-water samples collected in or 

near the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 

through 2011 ...............................................................................................................................32

21. Boxplots showing distribution of total dissolved solids concentration in surfacewater samples collected in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1985 through 2011 ..............................................................33

22. Boxplots showing distribution of hardness in surface-water samples collected 

in or near the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 

1985 through 2011 ......................................................................................................................35
viii

23. Boxplots showing distribution of chloride concentration in surface-water 

samples collected in or near the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, 1985 through 2011 ........................................................................................36

24. Boxplots showing distribution of phosphorus concentration in surface-water 

samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, 1985 through 2011 ..................................................................................................37

25. Graphs showing relations between total nitrogen concentration, total 

phosphorus concentration, and streamflow in surface-water samples collected 

at the North Canadian River near Harrah, Oklahoma, streamflow-gaging station, 

1985 through 2011 ......................................................................................................................38

26. Boxplots showing distribution of selected metals concentrations in surfacewater samples collected in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1985 through 2011 ..............................................................40

27. Boxplots showing distribution of fecal coliform bacteria in surface-water 

samples collected from the North Canadian River in or near the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 through 2011 ................41

28. Map showing principal aquifers and locations of sampled wells in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma ..................................................43

29. Boxplots showing distribution of depths of wells sampled from 1943 through 

2005 by aquifer in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma ....................................................................................................................................44

30. Boxplots showing distribution of values of selected water-quality constituents 

and properties by aquifer in groundwater samples collected in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1943 through 2011 ................45

31. Boxplots showing distribution of concentrations of major ions in groundwater 

samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, 1943 through 2005 ..................................................................................................46

32. Piper diagram showing proportions of major ions by aquifer in groundwater 

samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, 1943 through 2005 ..................................................................................................47

33. Graphs showing concentrations of selected water-quality constituents and 

properties with depth below land surface in groundwater samples collected 

in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1943 

through 2005 ...............................................................................................................................48

34. Boxplots showing distribution of concentrations of nitrite plus nitrate-nitrogen and 

dissolved phosphorus by aquifer in groundwater samples collected in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1943 through 2005 ................50

35. Boxplots showing distribution of concentrations of selected metals by aquifer 

in groundwater samples collected in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1947 through 2005 ..............................................................51

36. Map showing locations of sampled wells with uranium concentrations 

exceeding the primary drinking-water standard in the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma .....................................................................................53

Tables

1. Geographic and population data used to estimate water use in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma ....................................................5

2. Estimated water use, by type and source type in the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, 2005 .............................................................................8
ix

3. Statistics of seasonal Kendall tau tests of trends in mean annual streamflow with 

time at selected streamflow-gaging stations in the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, October 1984 to October 2011 ...............................23

4. Properties of aquifers underlying the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma ................................................................................................25

5. Names and locations of selected surface-water quality sites and weather 

stations sampled or measured in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1985 through 2011 ..............................................................27

6. Relative percent differences of constituents measured in replicate groundwater 

samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, 2003 through 2004 ..................................................................................................54

7. Constituent concentrations measured in blank samples associated with 

groundwater samples collected in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 2003 through 2004 ..............................................................55

Conversion Factors

Inch/Pound to SI

Multiply By 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

square mile (mi2) 2.590 square kilometer (km2) 

Volume

gallon (gal) 3.785 liter (L) 

million gallons (Mgal) 3,785 cubic meter (m3)

Flow rate

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

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

million gallons per day (Mgal/d) 0.04381 cubic meter per second (m3/s)

inch per year (in/yr) 25.4 millimeter per year (mm/yr)

Mass

pound, avoirdupois (lb) 0.4536 kilogram (kg) 

Specific capacity

gallon per minute per foot 

[(gal/min)/ft)]

 0.2070 liter per second per meter 

[(L/s)/m]

Hydraulic conductivity

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

SI to Inch/Pound

Multiply By To obtain

Length

centimeter (cm) 0.3937 inch (in.)

millimeter (mm) 0.03937 inch (in.)

meter (m) 3.281 foot (ft) 

kilometer (km) 0.6214 mile (mi)

Area

square kilometer (km2) 0.3861 square mile (mi2)

Volume

liter (L) 0.2642 gallon (gal)

cubic meter (m3) 0.0002642 million gallons (Mgal) 

Flow rate

cubic meter per second (m3/s) 35.31 cubic foot per second (ft3/s)

liter per second (L/s) 15.85 gallon per minute (gal/min) 

cubic meter per second (m3/s) 22.83 million gallons per day (Mgal/d) 

millimeter per year (mm/yr) 0.03937 inch per year (in/yr) 

Mass

kilogram (kg) 2.205 pound avoirdupois (lb)

Specific capacity

liter per second per meter 

[(L/s)/m]

4.831 gallon per minute per foot 

[(gal/min)/ft]

Hydraulic conductivity

meter per day (m/d) 3.281 foot per day (ft/d) 

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

°F=(1.8×°C)+32

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

°C=(°F-32)/1.8

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.

Specific conductance is given in microsiemens per centimeter at 25 degrees Celsius (μS/cm at 

25°C).

Concentrations of chemical constituents in water are given either in milligrams per liter (mg/L) 

or micrograms per liter (μg/L).
Analysis of Environmental Setting, Surface-Water 

and Groundwater Data, and Data Gaps for the 

Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma, Through 2011

By William J. Andrews, Christopher R. Harich, S. Jerrod Smith, Jason M. Lewis, Molly J. Shivers, 

Christian H. Seger, and Carol J. Becker

Abstract

The Citizen Potawatomi Nation Tribal Jurisdictional 

Area, consisting of approximately 960 square miles in parts of 

three counties in central Oklahoma, has an abundance of water 

resources, being underlain by three principal aquifers (alluvial/

terrace, Central Oklahoma, and Vamoosa-Ada), bordered by 

two major rivers (North Canadian and Canadian), and has 

several smaller drainages. The Central Oklahoma aquifer 

(also referred to as the Garber-Wellington aquifer) underlies 

approximately 3,000 square miles in central Oklahoma in parts 

of Cleveland, Logan, Lincoln, Oklahoma, and Pottawatomie 

Counties and much of the tribal jurisdictional area. Water from 

these aquifers is used for municipal, industrial, commercial, 

agricultural, and domestic supplies. 

The approximately 115,000 people living in this area 

used an estimated 4.41 million gallons of fresh groundwater, 

12.12 million gallons of fresh surface water, and 8.15 million 

gallons of saline groundwater per day in 2005. Approximately 

8.48, 2.65, 2.24, 1.55, 0.83, and 0.81 million gallons per day 

of that water were used for domestic, livestock, commercial, 

industrial, crop irrigation, and thermoelectric purposes, 

respectively. Approximately one-third of the water used in 

2005 was saline water produced during petroleum production. 

Future changes in use of freshwater in this area will be 

affected primarily by changes in population and agricultural 

practices. Future changes in saline water use will be affected 

substantially by changes in petroleum production. Parts 

of the area periodically are subject to flooding and severe 

droughts that can limit available water resources, particularly 

during summers, when water use increases and streamflows 

substantially decrease.

Most of the area is characterized by rural types of land 

cover such as grassland, pasture/hay fields, and deciduous 

forest, which may limit negative effects on water quality by 

human activities because of lesser emissions of man-made 

chemicals on such areas than in more urbanized areas. Much 

of the water in the area is of good quality, though some 

parts of this area have water quality impaired by very hard 

surface water and groundwater; large chloride concentrations 

in some smaller streams; relatively large concentrations of 

nutrients and counts of fecal-indicator bacteria in the North 

Canadian River; and chloride, iron, manganese, and uranium 

concentrations that exceed primary or secondary drinkingwater standards in water samples collected from small 

numbers of wells.

Substantial amounts of hydrologic and water-quality 

data have been collected in much of this area, but there are 

gaps in those data caused by relatively few streamflow-gaging 

stations, uneven distribution of surface-water quality sampling 

sites, lack of surface-water quality sampling at high-flow 

and low-flow conditions, and lack of a regularly measured 

and sampled groundwater network. This report summarizes 

existing water-use, climatic, geographic, hydrologic, and 

water-quality data and describes several means of filling gaps 

in hydrologic data for this area.

Introduction

Water-resources information is needed by the Citizen 

Potawatomi Nation and other interested parties to better 

understand those resources in their tribal jurisdictional area 

in central Oklahoma. Data analysis by the U.S. Geological 

Survey, in cooperation with the Citizen Potawatomi 

Nation, was done to provide information about geographic, 

hydrologic, and environmental features of the area and 

identifies gaps in data that, if filled, would provide better 

information about the water resources of this area. Information 

about previously collected data and gaps in data can be used 

for designing hydrologic sampling networks and for planning 

future uses of water in this tribal jurisdictional area. Additional 

details about characteristics of this area are presented later in 

this report.
2 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Purpose and Scope

The purposes of this report are to inventory and evaluate 

existing data and reports from Native-American Tribes 

(the Citizen Potawatomi Nation and the Kickapoo Tribe of 

Oklahoma), the U.S. Geological Survey (USGS), and other 

government agencies to summarize what types of wateruse, climatic, land-cover, hydrologic, and water-quality data 

have been collected; and the locations and dates of those 

data being collected in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area of central Oklahoma. This report includes 

information from previous studies, well logs, climatological 

descriptions, and data collected from long-term monitoring of 

streamflow, groundwater, and water quality in this area. This 

report also identifies “gaps” or deficiencies in those data in 

regards to geographic and temporal distribution and physical 

properties and constituents measured.

Location of the Study Area

The Citizen Potawatomi Nation Tribal Jurisdictional Area 

is a 960-square-mile area in central Oklahoma in parts of three 

counties: Cleveland, Oklahoma, and Pottawatomie (fig. 1). 

The North Canadian and Canadian Rivers form the northern 

and southern boundaries of the area (fig. 1).

Methods of Analysis

For this report, previously compiled geographic, climatic, 

geologic, hydrologic, and water-use data collected by a variety 

of agencies were summarized with maps and graphs and 

computation of summary and comparative statistics. Gaps in 

time, place, and types of those previously collected data also 

are summarized in this report.

Selection of Climatic and Geographic Data

Climatic data, including annual precipitation and mean 

annual temperature from January 1964 through December 

2010, were obtained for weather stations operated by the 

National Weather Service at Shawnee, Okla. (north of the 

tribal jurisdictional area), and Seminole, Okla. (east of this 

area), from the National Weather Service (written communs., 

1964–2010) and summaries in Oklahoma Climatological 

Survey (2011a) (fig. 1). Although there are other weather 

stations in this area, these two stations had the longest 

continuous records of precipitation amounts or temperature. 

Geographic data, including topographic, land-cover, soils, 

and other locational data, were obtained from Gesch and 

others (2002), Gesch (2007), Fry and others (2011), Natural 

Resources Conservation Service (2006), and U.S. Geological 

Survey (2012a).

Selection of Streamflow Data

For this report, streamflow data from four long-term 

USGS streamflow-gaging stations (station numbers in 

parentheses) in or on the boundaries of the jurisdictional 

area were analyzed: North Canadian River near Harrah, 

Okla. (07241550), North Canadian River at Shawnee, Okla. 

(07241800), Little River near Tecumseh, Okla. (07230500), 

and Canadian River at Purcell, Okla. (07229200). These 

stations were associated with a decade or more of continuous 

streamflow measurements through 2011. Periodic waterquality sampling by the USGS and other agencies was 

conducted at all of these stations except the North Canadian 

River at Shawnee, Okla., station.

To represent recent data, streamflow and water-quality 

data from these stations were summarized for the period 

October 1985 through September 2011 (North Canadian 

River near Harrah, Okla., Little River near Tecumseh, Okla.), 

October 1985 through September 2010 (Canadian River at 

Purcell, Okla.), and October 2001–September 2011 (North 

Canadian River at Shawnee, Okla.). Streamflow data for 

these stations were obtained from the USGS National Water 

Information System (NWIS) database (U.S. Geological 

Survey, 2012b). Streamflow data were summarized by 

monthly minimum, mean, and maximum streamflows, 

seasonal streamflow distributions, recurrence intervals and 

exceedance probabilities, and mean annual streamflows. 

LOESS trend lines (Cleveland, 1979) were used to 

indicate changes with time in annual peak flows at selected 

streamflow-gaging stations using the graphing function of 

the TIBCO Spotfire S+ 8.1 for Windows program (TIBCO 

Software, Inc., 2008). Recurrence intervals were calculated 

using the PeakFQ program (Flynn and others, 2006), which 

incorporates methods described in Interagency Advisory 

Committee on Water Data (1982).

Selection of Groundwater Data

For this report, groundwater data including well depths, 

water levels, and aquifer information from three sources 

were analyzed: the USGS NWIS database (U.S. Geological 

Survey, 2012c), the Oklahoma Department of Environmental 

Quality (in 2012 from the STORET database maintained by 

the U.S. Environmental Protection Agency [USEPA]) (U.S. 

Environmental Protection Agency, 2012), and from online 

records of the Oklahoma Water Resources Board (OWRB) 

(Oklahoma Water Resources Board, 2012). Dates of collection 

of data summarized in this report ranged from October 1943 

through September 2011. Analyses of these data included 

mapping locations of measured/documented wells by aquifer 

and comparing depths of wells completed in different aquifers.
Methods of Analysis 3

Figure 1. Location of the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, and locations of selected long-term 

streamflow-gaging stations and weather stations in and near that area.

Salt Creek

Harrah

CREEK COUNTY

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

MCCLAIN

COUNTY

GARVIN

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

LOGAN COUNTY

OKFUSKEE

COUNTY

§ ̈¦44

§ ̈¦35

§ ̈¦35

§ ̈¦240 § ̈¦40 § ̈¦40

Wes Watkins Reservoir

Lake

 Thunderbird

Stanley

Draper

Lake

Horseshoe

Lake

Little River

Canadian River

North Canadian River

Purcell

Shawnee

Tecumseh

Seminole

Base modified from U.S. Geological Survey

National Hydrography Dataset, 2012

Albers Equal-Area Conic projection

North American Datum of 1983

Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

97°20' 97°10' 97°00' 96°50' 96°40'

35°40'

35°30'

35°20'

35°10'

35°00'

34°50'

Citizen Potawatomi Nation

Tribal Jurisdictional Area

OKLAHOMA Oklahoma City

Shawnee,

Okla.

Tribal Jurisdictional Area

U.S. Geological Survey (USGS)

 streamflow-gaging station—

 USGS station name (USGS

 station number)

National Weather Service

 weather station and identifier

EXPLANATION

O

a

North Canadian

River near Harrah,

Okla. (07241550)

Shawnee

Reservoir

a

a

O

O

O

O

Little River

near Tecumseh,

Okla. (07230500)

Canadian River

at Purcell, Okla.

(07229200)

North Canadian

River near Harrah,

Okla. (07241550)

Shawnee,

Okla.

Seminole,

Okla.

North Canadian

River at Shawnee,

Okla. (07241800)
4 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Selection of Water-Quality Data

Surface-water-quality data were retrieved from the 

USGS NWIS database and the STORET database of the 

USEPA in January 2012 (U.S. Geological Survey, 2012d; U.S. 

Environmental Protection Agency, 2012). Additional surfacewater-quality data collected in the jurisdictional area were 

obtained from staff of the Citizen Potawatomi Nation and 

the Oklahoma Corporation Commission (S. Howard, Citizen 

Potawatomi Nation, written commun., 2012; P. Billingsley, 

Oklahoma Corporation Commission, written commun., 2012). 

Surface-water-quality data only were summarized from 

sites having three or more samples collected. The Citizen 

Potawatomi Nation and the Kickapoo Tribe of Oklahoma 

collected surface-water-quality data (physical properties and 

some nutrients) from 2009–11 at the time that this report was 

written. Nutrient data collected by the Citizen Potawatomi 

Nation were not included in this report, as only two samples 

collected in late 2011 at each of nine sites were available 

when this report was written. Surface-water-quality data from 

the Oklahoma Department of Environmental Quality were 

composed of analyses of counts of fecal-indicator bacteria in 

water-quality samples collected during 2003. 

The OWRB analyzed numerous water-quality properties 

and constituents in surface-water samples collected at 

11 stations on the North Canadian River and in the Salt 

Creek watershed for varying periods from 1998–2005. The 

Oklahoma Corporation Commission collected surface-waterquality samples from 1996–2001, primarily from small 

streams, for analyses of values of physical properties and 

concentrations of major ions associated with oilfield spills and 

leaks and natural seepage of brines.

Groundwater-quality data were obtained from the USGS 

NWIS database (U.S. Geological Survey, 2012d), which 

contained data from more than 700 groundwater samples 

collected in the area from the 1940s through the early 2000s. 

Agencies collecting those samples included the Association 

of Central Oklahoma Governments (ACOG), the OWRB, 

the Oklahoma State Health Department, private laboratories 

associated with the National Uranium Resource Evaluation 

project of the U.S. Department of Energy in the late 1970s 

and early 1980s, and the USGS. The STORET system of the 

USEPA (U.S. Environmental Protection Agency, 2012) was 

queried for groundwater-quality data collected in the study 

area, but missing data for (1) aquifers in which 68 wells 

were completed in the jurisdictional area and (2) depths of 

those wells precluded inclusion of those data for analysis in 

this report. Only groundwater-quality data collected from 

wells with known depths completed in known aquifers were 

included in this report for comparing groundwater quality 

between major aquifers (alluvial/terrace, Central Oklahoma, 

and Vamoosa-Ada) in the jurisdictional area and investigating 

relations of groundwater quality to well depth. To evenly 

weight water-quality data from each well in summary statistics 

(and not overweight data from more frequently sampled wells) 

and to portray the most recent groundwater quality, data from 

the last water sample collected from each well are summarized 

in this report.

All of the surface-water-quality data in this report 

are limited by the range of discharges at which they 

were collected. Surface-water quality at high flows can 

be substantially different than at low flow (Esralew and 

others, 2011a, b), with much of the annual loads of some 

constituents, such as suspended sediments and phosphorus, 

being transported at high flows. Because high streamflows 

occur for a very small percentage of the time, regularly-spaced 

(such as the second Tuesday of every month) sampling done 

by many agencies rarely coincides with peak streamflows. 

Some agencies also may avoid sampling at peak streamflows 

because of access and safety issues. The USGS has been 

collecting approximately six base-flow and six high-flow 

samples since 2005 at the North Canadian River near Harrah, 

Okla., streamflow-gaging station to better characterize 

surface-water quality at high-flow conditions. But even 

such “targeted” sampling for high flows may not represent 

surface-water quality across the entire range of streamflows 

at a particular location, as peaks in streamflow tend to be 

very short in duration. Water-quality data are summarized in 

this report primarily through tables of summary statistics and 

boxplots showing distribution of data; the Wilcoxon rank-sum 

test (Wilcoxon, 1945) was used to determine significant (at a 

p-value of 0.05 or less) differences in locations of distribution 

of data.

Estimation of Water Use

Water-use data have not been compiled specifically 

for this jurisdictional area but were compiled by county for 

2005 (Tortorelli, 2009). Estimates of water-use data for each 

of the three counties with land in the Citizen Potawatomi 

Nation Tribal Jurisdictional Area were obtained from data 

compiled for the USGS National Water-use Information 

Program in 2005 (R. Tortorelli, U.S. Geological Survey, 

written commun., 2012). Because much of this jurisdictional 

area is rural (table 1), water-use amounts are likely to be 

affected by different factors. Domestic water use is likely to 

be proportional to the number of people residing in the parts 

of the counties in this area. Commercial and industrial water 

use in this relatively rural area would be overrepresented by 

simply multiplying the percentage of county area or county 

population by the total water use in each of these three 

counties, given the much more urbanized areas outside of this 

jurisdictional area. Conversely, agricultural water use is likely 

to be disproportionately larger in this rural area compared to 

these counties in general.

To account for these geographic differences in water 

use, the following methods were used to adjust 2005 wateruse data for these three counties to estimate water use in this 

jurisdictional area:

1. Industrial and commercial water use was multiplied 

by the percentages of county populations in the tribal 

jurisdictional area (U.S. Census Bureau, 2012; table 1) 
Methods of Analysis 5

and by the ratio of percentage of impervious area in the 

jurisdictional area to percentage of impervious area in 

the counties (to correct for the more rural nature of the 

jurisdictional area);

2. Domestic water use was multiplied by the percentages of 

county populations in the tribal jurisdictional area;

3. Livestock and irrigation water use was multiplied by the 

percentage of county areas in the jurisdictional area and 

the ratio of percentage of tree-canopy cover (an indicator 

of rural land use) in the jurisdictional area to percentage 

of tree canopy cover in the counties;

4. Mining water use, which is primarily associated with 

petroleum production, was assumed to be uniform in the 

three counties and was multiplied by the percentage of 

county areas in the jurisdictional area; and

5. Thermoelectric water use was multiplied by the 

percentage of county populations in the jurisdictional 

area, which assumes that thermoelectric water use is 

proportional to the ratios of population in the three 

counties.

Analysis of Climatic and Geographic Data

Monthly precipitation data measured at the National 

Weather Service stations at Shawnee, Okla., and Seminole, 

Okla. (fig. 1), were summed to determine annual precipitation 

amounts in inches at each station. Some months, usually those 

with little rainfall, had missing data. Monthly precipitation 

data were summed for years with no more than one missing 

monthly precipitation value. Mean annual temperatures were 

not computed for years with one or more months of missing 

data. Mean monthly and annual temperatures were not 

recorded at the weather station at Shawnee, Okla.

Land-cover data were obtained from the National Land 

Cover database for 2006 (U.S. Geological Survey, 2012a). 

Among many different types of land-cover data, raster data 

describe the percentages of land cover for 30- by 30-meter 

cells. For computation of land-use percentages, the rasters 

were averaged over the counties and parts of the counties in 

the jurisdictional area using the ArcGIS “Zonal Statistics as 

Table” tool (Environmental Systems Research Institute, 2012). 

Analysis of Hydrologic Data

Surface Water

Streamflow is measured continuously (typically at 

15-minute intervals) at streamflow-gaging stations, of which 

there were nearly 200 in Oklahoma as of 2011. The USGS 

has periodically gaged streamflow at 36 streamflow-gaging 

stations in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area. Because streamflow data for many of 

these stations were discontinuous or discontinued before 2011, 

streamflow data from only four stations with recent and longterm streamflow-gaging records (North Canadian River near 

Harrah, Okla. (07241550), North Canadian River at Shawnee, 

Okla. (07241800), Little River near Tecumseh, Okla. 

(07230500), and Canadian River at Purcell, Okla. (07229200) 

are summarized in this report. The North Canadian River 

near Harrah, Okla., streamflow-gaging station (fig. 1) was 

in operation from 1968 through 2011. Data collected at that 

streamflow-gaging station represent streamflow and water 

Table 1. Geographic and population data used to estimate water use in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

Oklahoma.

[Land-cover data from U.S. Geological Survey (2012), county populations from U.S. Census Bureau (2012)]

Data type County

Cleveland Oklahoma Pottawatomie

County land area in jurisdictional area, in percent 62.9 19.2 81.2

Impervious area in the jurisdictional area, in percent 0.644 4.38 0.625

Impervious area in county, in percent 4.35 14.5 1.16

Tree canopy cover in the jurisdictional area, in percent 35.4 22.5 27.0

Tree canopy cover in county, in percent 25.8 17.0 24.4

County population 255,760 718,630 69,440

Population in the jurisdictional area 34,016 48,148 33,123

County population in the jurisdictional area, in percent 13.3 6.70 47.7

Population density in the jurisdictional area, in people per square mile 97 349 51
6 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

quality along the northern boundary of the area. The North 

Canadian River at Shawnee, Okla., streamflow-gaging station 

was in operation from 2001 through 2011, with streamflow 

at that station representing conditions downstream from 

the station near Harrah, plus contributions occurring as the 

river flowed along much of the northern boundary of this 

area. The Little River near Tecumseh, Okla., streamflowgaging station (fig. 1), in operation from 1943 through 2011, 

recorded streamflow data from the primary stream flowing 

through the center of the jurisdictional area. The Canadian 

River at Purcell, Okla., streamflow-gaging station (fig. 1), in 

operation from September 1959 through June 1961, October 

1979 through September 1983, and October 1985 to the 

present (2012), records streamflow entering this area on that 

river. The non-parametric seasonal Kendall tau test (Kendall, 

1938), which is based on changes in parameter values between 

sequential pairs of data values, was used to estimate trends in 

streamflow with time at selected streamflow-gaging stations.

Groundwater

The USGS has periodically collected groundwater 

data from the Central Oklahoma aquifer in the jurisdictional 

area since the 1940s. As of 2012, 460 groundwater-level 

measurements were recorded in the NWIS database for this 

area. The OWRB database had 25 wells with water-level 

measurements (Oklahoma Water Resources Board, 2012). 

The Oklahoma Climatological Survey had groundwater-level 

data from three wells associated with the Oklahoma Mesonet 

(Oklahoma Climatological Survey, 2012). The NWIS database 

had 799 groundwater-quality sites and the STORET database 

had 47 groundwater-quality sites.

Analysis of Water-Quality Data

Analysis of water-quality data in this report includes 

statistical summaries and regression computations, which 

were graphed on x:y graphs, boxplots, and maps showing 

geographic locations of sampling sites. For both surface-water 

quality and groundwater-quality data, left-censored data (data 

having values less than a reporting limit) were estimated 

using an adjusted maximum likelihood estimator (AMLE), 

which is a generalization of the widely accepted minimum 

variance unbiased estimator (Cohn, 2005), for computation 

of summary statistics and data distributions in boxplots. For 

graphs of water-quality constituent values compared with 

streamflow or well depth, left-censored water-quality data 

values were assumed to be equal to the method reporting 

level. For groups of data collected sequentially from surfacewater sites, serial correlation, which can affect the value of 

comparative statistical tests such as the Wilcoxon rank-sum 

test (used to compare locations of distribution of selected data 

sets [Wilcoxon, 1945]), was tested using the Durbin-Watson 

test (Durbin and Watson, 1950). Serial correlation of monthly 

streamflows did not occur at significance levels less than 

an alpha value of 0.05 for mean monthly streamflow data 

collected at the four streamflow-gaging stations described in 

this report.

Surface Water

Because different field sampling, processing, and 

laboratory analytical procedures used by Tribes and agencies 

can cause variations in accuracy and precision of waterquality data, data in this report are summarized by the 

collecting agency rather than being combined for each site. 

The USGS has periodically collected water-quality samples 

at 36 streamflow-gaging stations in or near the Citizen 

Potawatomi Nation Tribal Jurisdictional Area. For many 

of those streamflow-gaging stations, however, only a few 

water-quality samples were collected by the USGS, most of 

them having been collected in the 1960s or 1970s. Surfacewater-quality data collected at three USGS streamflow-gaging 

stations with the most numerous and recent water-quality 

data (North Canadian River near Harrah, Okla., 07241550, 

1985–2011; Little River near Tecumseh, Okla., 07230500, 

1985–2011; and Canadian River at Purcell, Okla., 07229200, 

1986–2011) are summarized in this report. Of these three 

streamflow-gaging stations, long-term comprehensive waterquality data have been collected only at the North Canadian 

River near Harrah, Okla., station, with water-quality data 

from the other stations being limited to measurement of a 

few physical properties (appendix 1). Staff of the Citizen 

Potawatomi Nation have measured physical properties 

periodically at nine sites in this jurisdictional area from 2010 

through 2011. Nutrient data were collected by the Citizen 

Potawatomi Nation staff in October and November 2011, but 

those data were too limited to be summarized in this report. 

Search of the STORET database of the U.S. Environmental 

Protection Agency provided additional surface-waterquality data collected by the Citizen Potawatomi Nation, 

the Oklahoma Department of Environmental Quality, the 

Kickapoo Tribe of Oklahoma, the OWRB, and the Oklahoma 

Corporation Commission in this area from the mid-1990s 

through 2011.

Groundwater

Groundwater-quality data in the NWIS database 

were collected in the area by the ACOG, the OWRB, 

private contractors of the U.S. Department of Energy, and the 

USGS from 1943–2005. Those data were analyzed only 

from wells completed in the three principal aquifers in this 

area to known depths. To avoid overweighting the data set 

with frequently sampled wells and to better represent more 

recent groundwater quality, only the last sample collected 

from each well was included in the analyzed groundwaterquality data set. Some older censored data in the USGS 
Evaluation of Water Use 7

NWIS database had values of zero (such as fluoride). For 

computational purposes, such data were transformed to 

values less than the smallest reported concentrations during 

that period or the values of left-censored data from later 

periods.

Quality Assurance

Quality assurance is the analysis of quality-control data 

to determine the quality of a process, such as manufacturing 

or sampling procedures. Quality-control data for waterquality samples commonly include analyses of blank and 

replicate samples. Blank samples typically consist of purified 

water processed through field-cleaned sampling equipment 

to determine whether equipment materials, field-cleaning, 

or environmental factors are contributing analytes to water 

samples. The USGS, the Kickapoo Tribe of Oklahoma, and 

the OWRB recorded some quality-contol-sample data in the 

NWIS and STORET databases. Some samples, such as those 

entered into the STORET database by the Kickapoo Tribe, 

included detailed descriptions of the types of quality-control 

samples for each sample, including field rinsate and laboratory 

blanks and splits and replicates for replicate samples. Because 

such information generally was not available for other 

agencies, data from quality-control samples are described 

only as “blanks” and “replicates” in this report. Data from 

blank samples are summarized in this report for minimum and 

maximum values and are compared to data values from field 

samples. For example, if the maximum concentration of a 

constituent in blank samples was 2 milligrams per liter (mg/L), 

with field-sample values ranging from 50–500 mg/L (a ratio 

of 25–250:1), sampling artifacts were assumed to be unlikely 

to affect constituent values in field samples. Blank samples 

were not always clearly denoted in the STORET database, 

though they typically could be separated from the field-sample 

data by having different time codes or substantially lesser 

constituent values than field samples (most data values being 

less than reporting limits).

After a lapse of a few minutes, replicate samples are 

collected after field samples to evaluate the variability of 

quality of a water source with time, water-quality changes 

caused by field procedures, and laboratory precision. Replicate 

groundwater-quality data generally were obtained by selecting 

groundwater-quality samples from the NWIS and STORET 

databases coded with sequential sample-collection times of a 

few minutes on the same day (for example 12:00 and 12:05). 

Some samples had multiple samples collected within a few 

minutes on the same day, representing more than one replicate 

per field sample.

Relative-percent differences (RPDs) indicate the degree 

of similarity between constituent values in field and replicate 

samples, with smaller relative-percent differences indicating 

greater similarity of data between pairs of field and replicate 

samples. RPDs of data from field samples and associated 

replicate samples were computed using the following 

equation:

RPD = (|a-b|/((a+b)/2))* 100 percent

where

a is the constituent value of the field 

sample, and

b is the constituent value of the replicate 

sample.

RPDs can be quite large for small differences in data 

values, for instance, the RPD between data values of 0.2 and 

0.3 is 40 percent, whereas, the RPD between data values of 3.2 

and 3.3 is only 3.1 percent, though the numerical difference 

between both pairs of numbers is 0.1.

Evaluation of Water Use

As described in the “Methods of Analysis” section of 

this report, water-use data compiled for the year 2005 and 

several scaling factors were used to estimate water use in the 

Citizen Potawatomi Nation Tribal Jurisdictional Area. Scaling 

factors were based on the percentages of county land areas in 

the jurisdictional areas and measures of urban development 

of those areas compared to all of Cleveland, Oklahoma, and 

Pottawatomie Counties.

Industrial and commercial uses generally are concentrated 

in urbanized rather than rural areas. As the jurisdictional area 

generally is in less urbanized parts of Cleveland, Oklahoma, 

and Pottawatomie Counties, there should be smaller 

proportions of water use than indicated by percentages of 

county areas in the jurisdictional area. Generally, industries 

and commercial facilities located near cities use public-water 

supplies rather than being self-supplied with water from wells 

or surface-water intakes. As is typical for these counties and 

the jurisdictional area, industrial and commercial water users 

primarily used public-water supplies withdrawn from surface 

water (table 2). Because most of the industrial water use from 

public-water supplies was in Oklahoma County (table 2), but 

a relatively small part of that county is in the jurisdictional 

area, only 6.9 percent of total industrial water use in these 

three counties was estimated to occur in the jurisdictional area. 

More than 90 percent of water used by commercial facilities 

such as stores, offices, and schools was obtained from publicwater supplies (table 2).

Domestic (household) water use normally dominates 

water use in urban areas and in rural areas with limited 

agriculture, such as the moderately forested jurisdictional 

area. The sum of self-supplied and public-supplied domestic 

water use was among the largest water-use categories in the 

jurisdictional area (table 2). The rural nature and relative lack 

of public-water supplies in much of the jurisdictional area 

contributed to estimates of nearly 30 percent of self-supplied 

domestic water use (assumed to be groundwater from wells) in 

these three counties being in the jurisdictional area (table 2). 

Future population growth in the jurisdictional area might 

increase the use of self-supplied and public-water supplies for 

domestic water use in towns and rural water districts.
8 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

With less urban development in the jurisdictional area 

than in the whole of these three counties, a greater proportion 

of water is likely to be used for livestock (primarily beef 

cattle) and crop irrigation than in the more urbanized parts 

of the three counties. Approximately 75 percent of water 

use by livestock in the three counties was estimated to have 

been used in this jurisdictional area, with almost 90 percent 

of that water coming from surface water (ponds and streams) 

(table 2). Irrigation water use in the jurisdictional area was 

estimated to range from only approximately 30 to 40 percent 

of the water used for irrigation in the three counties, primarily 

because of the relatively large amount of water used for 

irrigation in Oklahoma County and the relatively small part of 

Oklahoma County (19.2 percent) located in the jurisdictional 

area (table 2).

Mining in these three counties withdrew only saline 

groundwater, associated with drilling and pumping for oil 

and gas, and reinjected into deep strata to recover additional 

petroleum or disposed in deep wells completed in salinewater zones below freshwater aquifers (U.S. Geological 

Survey, 2013). Although the use of saline water typically is 

not associated with freshwater resources, saline waters are of 

interest as potential secondary water sources (U.S. Geological 

Survey, 2013). The relatively large amount of oil production in 

these counties makes mining/oil production a substantial user 

of water in this area, with an estimated 8.15 million gallons 

per day (Mgal/d) (fig. 2, table 2).

Water is used during power generation (thermoelectric 

water use) to drive turbines and for cooling purposes. The 

Horseshoe Lake gas-fired powerplant near the City of Harrah 

in Oklahoma County is the only large electrical generating 

plant in the jurisdictional area (U.S. Energy Information 

Administration, 2012), relying mostly on fresh surface water 

(table 2). 

Knowledge of the amounts of water use by type and by 

water source (surface water or fresh or saline groundwater) 

can be used for management and planning purposes. The 

approximately 115,000 people estimated to live in the 

jurisdictional area (U.S. Census Bureau, 2012), used an 

estimated 4.41 Mgal/d of fresh groundwater, 12.12 Mgal/d of 

fresh surface water, and 8.15 Mgal/d of saline groundwater 

in 2005. Approximately 8.48, 2.65, 2.24, 1.55, 0.83, and 

0.81 Mgal/d were used for domestic, livestock, commercial, 

industrial, crop irrigation, and thermoelectric purposes, 

respectively (fig. 2, table 2).

Future increases in use of freshwater in the tribal 

jurisdictional area most likely will be caused by increases 

in population (such as eastward expansion of development 

from the Oklahoma City metropolitan area and expansion 

around the City of Shawnee) and changes in agricultural 

practices (such as decreases or increases in livestock and 

irrigated cropland). Changes in saline water use largely will 

be affected by new petroleum production in the coming 

decades, particularly to extract remaining oil and gas from the 

Woodford shale that underlies much of the area (Menchaca, 

2012).

Table 2. Estimated water use, by type and source type in the 

Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 

2005.

[Mgal/d, million gallons per day; CPN TJSA, Citizen Potawatomi Nation 

Tribal Jurisdictional Area total]

Water-use type County/area

Estimated water use (Mgal/d) 

(total county water use 

in parentheses)

Groundwater Surface 

water

Industrial, 

self-supplied

Cleveland 0.00 (0.03) 0.00 (0.00)

Oklahoma 0.003 (0.06) 0.00 (0.00)

Pottawatomie 0.03 (0.07) 0.00 (0.00)

CPN TJSA 0.03 0.00 (0.00)

Industrial, public 

water supply

Cleveland 0.02 (0.17) 0.06 (0.69)

Oklahoma 0.10 (1.76) 1.09 (18.8)

Pottawatomie 0.00 (0.00) 0.25 (0.56)

CPN TJSA 0.12 1.40

Commercial, 

self-supplied

Cleveland 0.04 (0.40) 0.00 (0.00)

Oklahoma 0.05 (0.87) 0.00 (0.00)

Pottawatomie 0.00 (0.00) 0.00 (0.00)

CPN TJSA 0.09 0.00

Commercial, 

public water 

supply

Cleveland 0.22 (2.40) 0.73 (7.80)

Oklahoma 0.24 (4.06) 3.07 (52.90)

Pottawatomie 0.05 (0.11) 0.18 (0.40)

CPN TJSA 0.51 1.64

Domestic, 

self-supplied

Cleveland 0.14 (1.08) 0.00 (0.00)

Oklahoma 0.08 (1.19) 0.00 (0.00)

Pottawatomie 0.84 (1.77) 0.00 (0.00)

CPN TJSA 1.07 0.00

Domestic, public 

water supply

Cleveland 0.70 (5.30) 1.69 (12.70)

Oklahoma 0.70 (10.40) 3.12 (46.60)

Pottawatomie 0.25 (0.53) 0.95 (1.99)

CPN TJSA 1.65 5.76

Livestock, 

self-supplied

Cleveland 0.08 (0.09) 0.70 (0.81)

Oklahoma 0.06 (0.24) 0.16 (0.62)

Pottawatomie 0.19 (0.21) 1.46 (1.63)

CPN TJSA 0.33 2.32

Irrigation, 

self-supplied

Cleveland 0.07 (0.08) 0.02 (0.02)

Oklahoma 0.52 (2.06) 0.09 (0.35)

Pottawatomie 0.04 (0.05) 0.09 (0.10)

CPN TJSA 0.63 0.20

Mining/petroleum 

production, 

self-supplied 

(saline)

Cleveland 0.26 (0.41) 0.00 (0.00)

Oklahoma 0.60 (3.14) 0.00 (0.00)

Pottawatomie 7.29 (8.98) 0.00 (0.00)

CPN TJSA 8.15 0.00

Thermoelectric, 

self-supplied

Cleveland 0.00 (0.00) 0.00 (0.00)

Oklahoma 0.01 (0.13) 0.80 (7.30)

Pottawatomie 0.00 (0.00) 0.00 (0.00)

CPN TJSA 0.01 0.80
Summary of Climatic and Geographic Data 9

Figure 2. Estimated percentages and amounts of groundwater 

and surface water used in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area by use type in Oklahoma, 2005.

Fresh surface water

12.12 Mgal/d

Fresh groundwater

4.14 Mgal/d

Saline groundwater

8.15 Mgal/d

Thermoelectric

0.80 Mgal/d 

Domestic

 public

water supply

5.76 Mgal/d 

Commercial

public

water supply

1.64 Mgal/d 

Industrial

public

 water supply

1.40 Mgal/d 

Livestock

self-supplied

2.32 Mgal/d 

Irrigation

self-supplied

0.20 Mgal/d

Domestic

self-supplied

1.07 Mgal/d 

Domestic

public

water supply

1.65 Mgal/d 

Thermoelectric

self-supplied

0.01 Mgal/d 

Irrigation

self-supplied

0.63 Mgal/d 

Livestock

self-supplied

0.33 Mgal/d

Industrial public water supply 0.12 Mgal/d

Commercial

public

water supply

0.51 Mgal/d 

Commercial self-supplied 0.09 Mgal/d

Industrial self-supplied 0.03 Mgal/d

Fresh groundwater

4.44 million gallons per day (Mgal/d)

Fresh surface water

12.12 Mgal/d

Total water

24.41 Mgal/d

Summary of Climatic and Geographic 

Data

Climatic data described in this report include 

precipitation and air temperature data collected at weather 

stations. Geographic data selected for and described in this 

report include the following data types: physiographic, soils, 

geologic, and land cover. All of these data can be used to 

evaluate factors affecting water availability and quality in 

this area.

Climate

This area has a temperate continental climate, receiving 

an average of approximately 40 inches per year (in/yr) of 

precipitation and having approximately 50 inches of freesurface evaporation (Oklahoma Climatological Survey, 

2011b, c). Precipitation typically occurs from March through 

June and from September through November (Oklahoma 

Climatological Survey, 2011b). Monthly average air 

temperatures ranged from 35.9 degrees Fahrenheit (°F) 

in January to 81.5°F in July for 1965–2010 (Oklahoma 

Climatological Survey, 2011b). At weather stations in 

Shawnee, Okla., and Seminole, Okla., annual rainfall varied 

considerably from 1965–2010 (fig. 3). Most of the 1980s 

period was relatively wet, with annual precipitation exceeding 

40 in/yr (fig. 3). The 1990s through the early 2000s period was 

relatively dry, with annual precipitation typically ranging from 

30–40 in/yr (fig. 3). The mid- to late-2000s period had highly 

variable annual precipitation, exceeding 50 inches in some 

years and being less than 30 inches in others (fig. 3). Mean 

annual temperatures generally were less than 65°F during the 

relatively wet period of most of the 1980s, but increased to 

greater than 66°F at the weather station at Seminole, Okla., 

from the 1990s through 2010.

Physiography

The Citizen Potawatomi Nation Tribal Jurisdictional 

Area is in the Central Lowland Province of the Interior 

Plains Division described by Fenneman (1917). The area 

consists of gently rolling topography incised by deciduous 

stream drainage networks (fig. 4). The largest alluvial plains 

incised by streams are along the North Canadian River on the 

northern boundary of the area, the Little River draining from 

west to east in the central part of the area, Salt Creek in the 

southeastern part of the area, and the Canadian River along the 

southern border of the area (fig. 4).

Soils

The Citizen Potawatomi Nation Tribal Jurisdictional 

Area is underlain by soils that range in texture from fine 

silts to sandy loams. The Stephenville-Darnell Association, 
10 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

which underlies most of the area (fig. 5), consists of gently 

to strongly sloping loamy soil on uplands (Mayhugh, 1977). 

Soil series of this association are deep and well-drained with 

high natural fertility and organic matter in the surface of this 

red-brown silty clay loam (Mayhugh, 1977). Soils of the 

Gracemore-Dale-Canadian, Yahola-Gracemore-Gaddy, and 

the Yahola-Keokuk-Gaddy-Asher Associations underlie 

alluvial plain areas adjacent to the North Canadian and 

Canadian Rivers (fig. 5). Soil series of those associations 

tend to be deep, well-drained, and nearly level to gently 

sloping sandy loams (Mayhugh, 1977). The relatively highpermeability, well-drained soils of much of this area are 

likely to provide rapid recharge to underlying alluvial/terrace 

and bedrock aquifers and may become excessively dry for 

nonirrigated crops during the hot, dry summers typical of this 

area (Johnson, 1983).

Geology

The Garber Sandstone and Wellington Formation of Early 

Permian age and the Oscar Group of Late Pennsylvanian age 

(between 307 and 299 million years old), which underlie 

the western two-thirds of this area and neighboring areas 

to the north and west, consist of interbedded fine-grained 

sandstones, shales, and conglomerates (Hart, 1974; Bingham 

and Moore, 1975; Johnson, 1983; Press and Siever, 1978). 

The Vanoss Formation, Ada Group, and Vamoosa Formation 

of Late Pennsylvanian age, which underlie the eastern 

one-third of the area, consist of fine- to very fine-grained 

sandstone interbedded with conglomerates, shale, siltstone, 

and very thin limestone layers (Hart, 1974; Bingham and 

Moore, 1975; Johnson, 1983; Morton, 1986). Bedrock 

strata in this area dip gently toward the west at less than one 

degree (Bingham and Moore, 1975). Alluvial and terrace 

materials along stream channels consist of complexly bedded 

unconsolidated (uncemented) gravel, sand, silt, clay, and 

organic detritus ranging in age from Tertiary to Holocene 

(less than 2.6 million years old) (Hart, 1974; Bingham 

and Moore, 1975; Johnson, 1983; Morton, 1986). Variable 

lithologies, cementation, permeabilities, and fracturing of 

these units indicate variable availability of groundwater for 

wells and base flow of streams across this area.

Figure 3. Annual precipitation and mean annual temperature at selected weather stations in or near the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, 1965 through 2010.

Year

1964 1970 1980 1990 2000 2010

Mean annual temperature,

in degrees Fahrenheit

70

68

66

64

62

60

Precipitation, in inches per year

60

50

40

30

20

Annual precipitation at

 Shawnee, Okla.

Annual precipitation at

 Seminole, Okla.

Mean annual temperature

 at Seminole, Okla.

EXPLANATION
Summary of Climatic and Geographic Data 11

Figure 4. Land surface of the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma.

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

Citizen Potawatomi Nation Tribal

 Jurisdictional Area boundary

EXPLANATION

Base modified from U.S. Geological Survey digital data, 1983, 1:100,000

Universal Transverse Mercator, zone 14

North American Datum of 1983

Shaded relief from Gesch, 2007; Gesch and others, 2002

Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

97°00' 96°40' 97°20'

35°20'

35°00'

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

OKFUSKEE COUNTY

MCCLAIN

COUNTY

Horseshoe

Lake

Stanley

Draper

Lake

Lake

 Thunderbird

Shawnee

Reservoir

Wes Watkins

Reservoir

LITTLE RIVER VALLEY

NORTH CANADIAN RIVER VALLEY

SALT CREEK VALLEY

CANADIAN RIVER VALLEY
12 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 5. Soil associations in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma.

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

EXPLANATION

Soil associations

 Gracemore-Dale-Canadian Association

 Yahola-Gracemore-Gaddy Association

 Reinach-Dale-Brewer Association

 Port Association

 Zaneis-Renfrow-Grainola-Coyle Association

 Seminole-Gowton-Chickasha Association

 Vanoss-Teller-Norge-Konawa Association

 Yahola-Keokuk-Gaddy-Asher Association

 Konawa-Eufaula-Dougherty Association

 Stephenville-Darnell Association

 Water

Citizen Potawatomi Nation Tribal

 Jurisdictional Area boundary

Base modified from U.S. Geological Survey digital data, 1983, 1:100,000

Universal Transverse Mercator, zone 14

North American Datum of 1983

Soil unit data from U.S. Department of Agriculture

Natural Resources Conservation Service, 2006

97°00' 96°40' 97°20'

35°20'

35°00'

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

OKFUSKEE COUNTY

MCCLAIN

COUNTY

Horseshoe

Lake

Stanley

Draper

Lake

Lake

 Thunderbird

Shawnee

Reservoir

Wes Watkins

Reservoir
Evaluation of Hydrologic Data 13

Land Cover

The predominant types of land cover in this area are 

deciduous forest and herbaceous vegetation (shrubs and 

natural grassland), which dominate the central part of the area 

(figs. 6 and 7). Cropland and pasture/hay are predominant 

land-cover types on flatter land along major streams and in 

the southwestern part of the area (fig. 6). The relatively rural 

nature of the land cover, small population densities, and 

limited urbanized character of this area combine to produce 

a relatively small demand for water compared to surrounding 

urban areas and limited potential sources of water-quality 

degradation in this area.

Evaluation of Hydrologic Data

To evaluate water resources of the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, streamflow, groundwaterlevel, and well-yield data are summarized in this report. 

Streamflow characterization included evaluation of amounts 

and frequencies of high flows and low flows and general 

trends in streamflow with time. Groundwater characterization 

included showing locations of wells completed in the three 

principal aquifers in the area and a summary table of aquifer 

properties in the jurisdictional area.

Surface Water

To summarize streamflow characteristics in or near 

the Citizen Potawatomi Nation Tribal Jurisdictional Area, 

seasonality, magnitudes and frequencies of floods, low-flow 

characteristics, and long-term trends were summarized for 

four streamflow-gaging stations in or near this area using data 

collected by the USGS from October 1984 through September 

2011 (also known as water years 1985–2011) (fig. 1). Those 

four long-term stations produced data used for evaluation of 

streamflow characteristics of three of the major streams in or 

bordering this area, including:

1. Along the northern boundary of the area (North Canadian 

River approximately 10 miles downstream from the 

northwestern corner of the area, North Canadian River 

near Harrah, Okla., streamflow-gaging station and North 

Canadian River approximately 8 miles upstream from the 

northeastern corner of the area, North Canadian River at 

Shawnee, Okla., streamflow-gaging station);

2. In the central part of the area (Little River approximately 

10 miles before flowing out of the area, Little River near 

Tecumseh, Okla., streamflow-gaging station); and

3. Along the southern boundary of the area (Canadian River 

approximately 5 miles downstream from the southwestern 

corner of the area, Canadian River at Purcell, Okla., 

streamflow-gaging station).

Seasonality of Streamflow

Peaks in streamflow typically occur during the periods 

of greatest precipitation in the spring and the fall, with the 

largest peaks in streamflow generally being associated with 

intense convective storms during the spring; long periods 

of low flow typically occur during the summer and winter 

(figs. 8 and 9). Streamflow at the four long-term streamflowgaging stations described in this report indicates different 

seasonal patterns in maximum, mean, and minimum monthly 

streamflows (fig. 9). Regulation of streamflow by upstream 

dams probably has modified seasonal streamflow patterns 

of those streams. Regulation and discharge of treated 

municipal and industrial wastewater upstream from the North 

Canadian River near Harrah, Okla., and North Canadian 

River at Shawnee, Okla., streamflow-gaging stations probably 

contribute to larger minimum streamflows during the summer 

than at the other two stations (Esralew and others, 2011a), 

and more consistent annual peaks of maximum, mean, and 

minimum streamflow in May through June each year (fig. 9). 

The Little River near Tecumseh, Okla., and Canadian River 

at Purcell, Okla., streamflow-gaging stations tended to have 

larger minimum streamflows from January through early 

summer, with the greatest mean and maximum streamflows 

occurring in May (fig. 9). Grouping mean monthly streamflow 

at these streamflow-gaging stations into four seasonal periods 

indicated that significantly greater streamflow occurred during 

the spring season (March through May) at the three stations 

on the North Canadian and Canadian Rivers (fig. 10) from 

October 1985 through September 2011. Except for spring, 

the locations of distribution of seasonal streamflow at each 

of those streamflow-gaging stations were not significantly 

different (fig. 10). 
14 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 6. Land cover in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 2006.

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

EXPLANATION

Land cover

 Open water

 Lawn grasses

 Developed, low intensity

 Developed, medium intensity

 Developed, high intensity

 Barren land

 Deciduous forest

 Evergreen forest

 Grammanoid or herbaceous vegetation

 Pasture or hay

 Cultivated crops

 Emergent herbaceous wetlands

Citizen Potawatomi Nation Tribal

 Jurisdictional Area boundary

Base modified from U.S. Geological Survey digital data, 1983, 1:100,000

Universal Transverse Mercator, zone 14

North American Datum of 1983

Land-cover data from Multi-Resolution Land Characteristics Consortium

National Land Cover Database (U.S. Geological Survey, 2012a)

97°00' 96°40' 97°20'

35°20'

35°00'

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

OKFUSKEE COUNTY

MCCLAIN

COUNTY

Horseshoe

Lake

Stanley

Draper

Lake

Lake

 Thunderbird

Shawnee

Reservoir

Wes Watkins

Reservoir
Evaluation of Hydrologic Data 15

Magnitudes and Frequencies of Floods

Knowledge of magnitudes and frequencies of floods 

is useful for minimizing risk to flood-plain properties and 

managing water utilities that use surface water to produce 

treated water for human consumption and other purposes. 

Recurrence intervals of streamflow at the four selected USGS 

streamflow-gaging stations (fig. 11) indicate the probability 

of specific streamflows in a given year. For instance, a 

streamflow with a 100-year recurrence interval (commonly 

known as a 100-year flood) has an exceedance probability or 

chance of being measured in any given year of 1.00 percent or 

1 in 100. However, a streamflow with a 100-year recurrence 

interval may happen more frequently than a given recurrence 

interval, with several such streamflows possibly happening in 

one year. Streamflow associated with recurrence intervals was 

substantially different between these four streamflow-gaging 

stations, with 100-year recurrence interval streamflow ranging 

from approximately 15,000 cubic feet per second (ft3/s) at the 

Little River near Tecumseh, Okla., streamflow-gaging station 

to nearly 150,000 ft3/s at the Canadian River at Purcell, Okla., 

streamflow-gaging station (fig. 11).

Flood stages set by the National Weather Service for the 

four streamflow-gaging stations (National Weather Service, 

2012) and recurrence intervals of selected streamflows 

indicate different frequencies of occurrence of water 

levels above flood stages, ranging from floods occurring 

more frequently than every 2 years at the Little River near 

Tecumseh, Okla., streamflow-gaging station to approximately 

once every 2.5 years at the Canadian River at Purcell, Okla., 

streamflow-gaging station, with flood stages being related to 

the morphology of banks along stream channels and flow of 

water outside of normal stream channels.

Figure 7. Percentages of land cover in the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, 2006. 

Herbaceous vegetation

(37.7 percent)

Deciduous forest

(39.4 percent)

Evergreen forest

(0.07 percent)

Developed (1.57 percent)

Barren (0.20 percent)

Water (1.79 percent)

Wetlands (0.02 percent)

Cultivated crops (3.72 percent)

Pasture/hay (8.75 percent) Lawns (6.82 percent)

Land-cover type, in percent of land-surface area

(Fry and others, 2011)
16 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Low-Flow Characteristics

Low flow is a term used to describe minimal flows in 

streams during extended dry periods. Low-flow characteristics 

of streams primarily are used to manage permitted discharges 

of treated wastewater from municipal and industrial treatment 

plants and to maintain minimum streamflows needed for 

aquatic wildlife (known as in-stream flows or ecological 

flows), and for agricultural, recreational, and aesthetic 

purposes. As with high flows, recurrence intervals of low 

flows can be used for planning and management of surfacewater resources. As shown on figures 8, 9, and 10, at the Little 

River near Tecumseh, Okla., streamflow-gaging station, there 

can be periods of less than 1 ft3/s streamflow during summers. 

Recurrence intervals of low-flow periods for streamflow at 

both that station and the Canadian River at Purcell, Okla., 

streamflow-gaging station reach zero for one or more days 

every 10–20 years (fig. 12). For recurrence intervals of 5 

years, which have a one-in-five chance of occurring in a given 

year, low flows ranged from approximately 2 ft3/s for 1-day 

durations at the Little River near Tecumseh, Okla., station to 

about 75 ft3/s for 30-day durations at the North Canadian River 

at Shawnee, Okla., station (fig. 12). Because of upstream 

regulation and large, relatively continuous discharges of 

treated wastewater upstream from the North Canadian River 

station, low flows at those stations maintain 50 ft3/s or greater 

for all consecutive days of flow periods (fig. 12). The 7-day, 

2-year discharge (7Q2) shown on figure 12, commonly is used 

to manage permit applications for water allocation, watersupply planning, aquatic/ecological maintenance (in-stream 

flow), and waste-load allocations (East, 1999).

Figure 8. Monthly mean streamflow at four long-term streamflow-gaging stations in or near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, October 1985 through September 2011.

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

Year

0.1

1

10

100

1,000

10,000

100,000

Monthly mean streamflow, in cubic feet per second

07241550 North Canadian River

 near Harrah, Oklahoma

07241800 North Canadian River

 at Shawnee, Oklahoma

07230500 Little River near

 Tecumseh, Oklahoma

07229200 Canadian River at

 Purcell, Oklahoma

EXPLANATION
Evaluation of Hydrologic Data 17

Figure 9. Monthly maximum, mean, and minimum streamflow at four long-term streamflow-gaging stations in or near the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, October 1985 through September 2011.

Oct. Nov. Dec. Jan. Feb. Mar. Apr. May June July Aug. Sept.

Month

Streamflow, in cubic feet per second

9,000

1,000

100

10

1

0.1

9,000

1,000

100

10

1

0.1

9,000

1,000

100

10

1

0.1

9,000

1,000

100

10

1

0.1

07229200 Canadian River at Purcell, Okla.

07230500 Little River near Tecumseh, Okla.

07241550 North Canadian River near Harrah, Okla.

07241800 North Canadian River at Shawnee, Okla. (Mar. 2001–Sept. 2011)

EXPLANATION

Maximum

Mean

Minimum
18 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 10. Distributions of streamflow by season at four long-term streamflow-gaging stations in or near the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, October 1985 through September 2011.

Season

(Months)

Winter 

(Dec.–Feb.)

Spring

(Mar.–May)

Summer 

(June–Aug.)

Fall

(Sept.–Nov.)

10,000

1,000

100

10

1

0.1

10,000

1,000

100

10

1

0.1

10,000

1,000

100

10

1

0.1

10,000

1,000

100

30

Mean monthly streamflow, in cubic feet per second

x

x

78 78 78 78

30 33 33 31

78 78 78 78

78 78 77 77

07229200 Canadian River at Purcell, Okla.

07230500 Little River near Tecumseh, Okla.

07241550 North Canadian River near Harrah, Okla.

07241800 North Canadian River at Shawnee, Okla.

B A A A

A, B

A, B

B

A

A

A A A

B A A

A

x

A

78

EXPLANATION

Constituent distributions with the 

 same letter are not significantly 

 different (p-value of the Wilcoxon

 rank-sum test less than or equal to

 0.05)

Number of values

Upper outside

Upper adjacent

75th percentile

Median

25th percentile

Lower adjacent
Evaluation of Hydrologic Data 19

Figure 11. Recurrence intervals and exceedance probabilities of selected streamflows at four long-term streamflow-gaging stations in 

and near the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 through 2010.

2 5 10 20 25 30 40 50 60 70 80 90

Recurrence interval, in years

0 100

Exceedance probability, in percent per year

50 20 10 4 2 1

10,000

200,000

100,000

1,000

10,000

200,000

100,000

1,000

10,000

200,000

100,000

1,000

10,000

200,000

100,000

1,000

Streamflow, in cubic feet per second

07241550 North Canadian River near

Harrah, Okla. (water years 1984–2010)

07229200 Canadian River at Purcell,

Okla. (water years 1985–2010)

07230500 Little River near Tecumseh,

Okla. (water years 1984–2011)

07241800 North Canadian River at

Shawnee, Okla. (water years 2001–2011)

Flood stage (12 feet)

Flood stage (14 feet)

Flood stage (18 feet)

Flood stage (11 feet)

Recurrence intervals computed from data obtained from U.S. Geological Survey, 2012b.

Flood stages obtained from National Weather Service, 2012.
20 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 12. Recurrence intervals of low-flow streamflows by duration for four long-term streamflow-gaging stations in or near the 

Citizen Potawatomi Tribal Jurisdictional Area, Oklahoma.

0 5 10 15 20 25

Recurrence interval, in years

0

0

Streamflow, in cubic feet per second

7

6

4

2

0

0

300

250

200

150

100

50

300

250

200

150

100

50

300

250

200

150

100

50

07241550 North Canadian River near Harrah, Okla.

07229200 Canadian River at Purcell, Okla.

07230500 Little River near Tecumseh, Okla.

07241800 North Canadian River at Shawnee, Okla.

Oct. 1984–Sept. 2011

Oct. 2001–Sept. 2011

Oct. 1984–Sept. 2011

Oct. 1985–Sept. 2010

Consecutive days of low flow

EXPLANATION

30 days

7 days

1 day
Evaluation of Hydrologic Data 21

Long-Term Trends

Mean annual streamflows in or near this area decreased 

from the 1940s through the 1970s, increased during the 1980s, 

and decreased again in the early 1990s (Esralew and Lewis, 

2010). At four selected streamflow-gaging stations, mean 

annual streamflow has decreased since the mid-1980s, with 

notable short-term increases being measured in the mid1990s and 2007, and the most substantial decreases being 

measured in the drought year of 2006 (Tortorelli, 2008) and 

2011 (fig. 13). Those streamflow patterns generally coincided 

with patterns of annual precipitation recorded at the National 

Weather Service stations at Shawnee, and Seminole, Okla. 

(figs. 3 and 13). There were not enough complete mean annual 

temperature records at the National Weather Service station at 

Seminole, Okla., to make conclusions about relations between 

long-term temperature trends and streamflows (fig. 3).

Annual peak flow is the maximum streamflow recorded 

in a given year at a streamflow-gaging station. As with 

high-flow and low-flow characteristics, long-term changes 

in annual peak flow had different patterns with time at these 

four streamflow-gaging stations (fig. 14). Annual peak flows 

at the North Canadian River near Harrah, Okla., streamflowgaging station increased from 1985 to a peak in the mid1990s and generally have decreased since that peak (fig. 14). 

Relatively small decreases in peak flows, with numerous 

high outlier values from the mid-1990s through 2010, may 

have been caused by increased urbanization and impervious 

surface area in the upstream Oklahoma City area, causing 

“flashier” or more rapid runoff of water during storms. Annual 

peak streamflows at the North Canadian River at Shawnee 

station increased in the latter half of the first decade of the 

2000s, coinciding with several relatively wet years (figs. 3 

and 14). Similar to the monthly mean streamflows (fig. 9), 

annual peak streamflow at the Little River near Tecumseh, 

Okla., streamflow-gaging station generally decreased with 

time (fig. 14). After an increase in annual peak flow from 

1980 through 1990, annual peak flows at the Canadian River 

at Purcell, Okla., streamflow-gaging stations decreased to 

less than 20,000 ft3/s for most years in the 2000s, similar to 

the pattern of annual precipitation at local National Weather 

Service stations (figs. 3 and 14).

Mean annual streamflow from October 1984 through 

September 2011 (water years 1985–2011) at the three longterm streamflow-gaging stations on the larger rivers (North 

Canadian and Canadian) did not change significantly (p-value 

less than 0.05 for the seasonal Kendall tau test [Kendall, 

1938]; table 3). Trend analysis was not done for data with 

the relatively short period of record at the North Canadian 

at Shawnee, Okla., station. Mean annual streamflow did 

decrease significantly at the Little River near Tecumseh, Okla., 

streamflow-gaging station, indicating more consistent decrease 

in mean annual streamflow at the station than at the other two 

streamflow-gaging stations (table 3). 

Figure 13. Mean annual streamflow at four long-term streamflow-gaging stations in and near the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, October 1985 through September 2011.

Water year

1985 1990 1995 2000 2005 2010

Mean annual streamflow, in cubic feet per second

2,500

2,000

1,500

1,000

500

0

EXPLANATION

07241550 North Canadian River near Harrah, Okla.

07241800 North Canadian River at Shawnee, Okla.

07230500 Little River near Tecumseh, Okla.

07229200 Canadian River at Purcell, Okla.
22 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 14. Annual peak flows and LOESS trend lines for selected periods at four long-term streamflow-gaging stations in or near the 

Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 through 2010.

1985 1990 1995 2000 2005 2010

Water year (October 1 of preceding year through September 30)

110,000

100,000

80,000

60,000

40,000

20,000

0

110,000

100,000

80,000

60,000

40,000

20,000

0

Annual peak flow, in cubic feet per second

110,000

100,000

80,000

60,000

40,000

20,000

0

110,000

100,000

80,000

60,000

40,000

20,000

0

Annual peak flow

Locally-weighted scatterplot

 smoothing (LOESS) trend line

 (Cleveland, 1979)

EXPLANATION

07241550 North Canadian River near Harrah, Okla.

07230500 Little River near Tecumseh, Okla.

07229200 Canadian River at Purcell, Okla.

07241800 North Canadian River at Shawnee, Okla.
Evaluation of Hydrologic Data 23

Groundwater

The principal aquifers in this jurisdictional area are 

alluvial and terrace aquifers along the North Canadian and 

Canadian Rivers, referred to herein as “alluvial aquifers,” 

the Central Oklahoma aquifer in the western two-thirds of 

the area, and the Vamoosa-Ada aquifer in the eastern onethird of the area (fig. 15). Different textures and degrees 

of cementation of these aquifer materials produce varying 

hydrologic properties.

Alluvial aquifers are the thinnest aquifers in the area, 

generally being less than 100 feet (ft) thick, compared to 

several hundred to more than 1,000 ft of bedrock aquifers 

underlying the area. Despite being relatively thin, alluvial 

aquifers in the area produce some of the highest well yields, 

in some cases exceeding 1,000 gallons per minute (gal/min; 

table 4). Wells completed in the Central Oklahoma aquifer 

in the western part of the area generally produce 25–50 gal/

min, whereas wells completed in the Vamoosa-Ada aquifer in 

the eastern part of the area generally produce less than 25 gal/

min (Bingham and Moore, 1975). Specific capacity, the well 

yield per unit of drawdown, ranged from 0.29 gallons per 

minute per foot [(gal/min)/ft] for the North Canadian alluvial 

aquifer in northwestern Oklahoma to 0.36–1.3 (gal/min)/

ft for the Central Oklahoma aquifer to 0.48–1.3 (gal/min)/ft 

for the Vamoosa-Ada aquifer in Osage County, Okla. (Davis 

and Christenson, 1981; Parkhurst and others, 1996; Abbott 

and DeHay, 2008). Johnson (1983) described the part of 

the areas underlain by the alluvial and Central Oklahoma 

aquifers as being likely recharge areas, whereas the area 

underlain by the Vamoosa-Ada aquifer was a “potential 

recharge area.”

The Central Oklahoma aquifer underlies much of this 

jurisdictional area (fig. 15). Groundwater flow in the Central 

Oklahoma aquifer probably is confined by the Hennessey 

Group, which is composed mostly of shales and mudstones 

with relatively small transmissivities. The Central Oklahoma 

aquifer also is considered to be confined at the contact with 

the Late Pennsylvanian-age Vanoss Formation. Groundwater 

flow also is likely to be limited at the base of the aquifer as 

indicated by the presence of saline groundwater (Parkhurst and 

others, 1996; Christenson and others, 1998).

Regional groundwater flow can be inferred from 

potentiometric-surface maps of the Central Oklahoma aquifer. 

A potentiometric surface is defined as the level to which 

water will rise in tightly cased wells. Multiple potentiometric 

surfaces can occur in an aquifer with substantial vertical 

groundwater flow. Most of the deep wells completed in 

this aquifer are constructed with long gravel packs and 

multiple open intervals (screens, slots, or perforations) 

that are completed in more than one sandstone layer, with 

each containing water at different head elevations. The 

potentiometric surfaces described in this report approximate 

only the upper zone of saturation in the Central Oklahoma 

aquifer, referred to as the “water table.” Two synoptic 

water-level measurement efforts have been performed in 

the Central Oklahoma aquifer. The first potentiometric 

measurements in this area were made in 1986–87 as part of 

studies about the geochemistry in the aquifer. Those studies 

of the Central Oklahoma aquifer produced maps of the 

1986–87 potentiometric surface in the aquifer (Christenson 

and others, 1992, fig. 2; Parkhurst and others, 1996, fig. 24). 

An additional series of measurements of groundwater levels 

in this aquifer were made in 2009 for compilation of a 

groundwater flow model of the Central Oklahoma aquifer. For 

that study, groundwater levels were measured in 280 wells 

between February 17, 2009, and March 13, 2009 (Mashburn 

and Magers, 2011). Well depths and completion information 

for wells used in the 1986–87 and 2009 potentiometric-surface 

maps can be found at the USGS National Water Information 

System website http://nwis.waterdata.usgs.gov/ok/nwis/

gwlevels. The potentiometric surfaces from 1986–87 and 

2009 measurements of the Central Oklahoma aquifer can 

be compared to generally characterize long-term changes in 

groundwater levels for those time periods. The water levels 

compared in this section are only from those wells measured 

in the 1986–87 and 2009 time periods (169 wells, fig. 15). 

This comparison does not take into account the variability 

of water levels between 1986–87 and 2009. Various factors 

also play a role in water-level changes and some factors may 

affect water levels on a diurnal, seasonal, or annual timescale. 

These factors include earth and moon tides, barometricpressure changes, groundwater gains from precipitation and 

streamflows, and groundwater losses to withdrawals and 

streamflows.

Table 3. Statistics of seasonal Kendall tau tests of trends in mean annual streamflow with time at selected streamflow-gaging stations 

in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, October 1984 to October 2011.

[bold font, significant trend at alpha level less than or equal to 0.05]

Streamflow-gaging station Tau correlation 

coefficient S-value Z-value P-value Estimated trend equation

07241550 North Canadian River near Harrah, Oklahoma -0.254 -89 -1.84 0.067 Q = -12.75(Year)+683.0

07230500 Little River near Tecumseh, Oklahoma -0.339 -119 -2.46 0.014 Q = -7.606(Year)+257.4

07229200 Canadian River at Purcell, Oklahoma1 -0.227 -68 -1.56 0.118 Q = -19.36(Year)+950.6

1

Data only available for water years 1986–2010. 
24 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 15. Principal aquifers and locations of 460 wells having depth-to-water measurements collected by the U.S. Geological Survey 

in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, as of 2011.

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

Wes Watkins Reservoir

Lake

 Thunderbird

Stanley

Draper

Lake

Horseshoe

Lake

Shawnee

Reservoir

Salt Creek

Little River

Canadian River

North Canadian River

Base modified from U.S. Geological Survey digital data, 1983, 1:100,000

Albers Equal-Area Conic projection

North American Datum of 1983

Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

Aquifer boundaries from Oklahoma Water Resources Board, 2011

97°20' 97°10' 97°00' 96°50' 96°40'

35°30'

35°20'

35°10'

35°00'

Aquifer

 Alluvial

 Central Oklahoma

 Vamoosa-Ada

Citizen Potawatomi Nation Tribal

 Jurisdictional Area boundary

Well—Site with depth-to-water

 measurement

EXPLANATION
Evaluation of Water-Quality Data 25

The 2009 potentiometric-surface map (Mashburn and 

Magers, 2011) showed similar features as the 1986–87 

potentiometric-surface map (Christenson and others, 1992, 

fig. 2). Regional slope was west to east and, based on no 

deviation of potentiometric lines near the North Canadian 

River, there appeared to be little or no exchange between 

the Central Oklahoma aquifer and the North Canadian River 

(Mashburn and Magers, 2011). Greater exchange between 

groundwater and the North Canadian River probably occurs 

in overlying alluvial aquifers. The 1986–87 water levels, or 

depths to water, in feet below land surface, ranged from 1.5 

to 177 with a median value of 32 ft (Christenson and others, 

1992, fig. 2). The 2009 water levels, in feet below land 

surface, ranged from 3.1 to 233.7 with a median value of 35.8 

ft (Mashburn and Magers, 2011). 

Evaluation of Water-Quality Data

The quality of surface water and groundwater in the 

Citizen Potawatomi Nation Tribal Jurisdictional Area is 

described in this report through summaries and analyses of 

values and concentrations of selected physical properties, 

major ions, nutrients, and metals in surface water and 

groundwater during the past several decades. Boxplots are 

used to graphically display distributions of those data values 

from different surface-water sites and aquifers.

Surface-Water Quality

Surface-water quality typically ranges from being 

similar to local groundwater during low-flow conditions 

to being similar to stormwater runoff during high-flow 

conditions. Water quality in streams generally is correlated 

with streamflow, with some constituents occurring in 

greater or lesser values or concentrations at high-flow or 

low-flow conditions, respectively, depending on the source 

of a constituent and interactions with other water-quality 

constituents. With the exception of the data from the USGS 

and the Citizen Potawatomi Nation, most surface-waterquality samples did not have accompanying streamflow 

data, limiting comparison between streamflow and surfacewater quality in this report. Comparisons made between 

water-quality data collected at different stations by different 

agencies are limited by a number of possible factors, including 

differences in: sample-collection methods, measurement 

instrumentation and calibration procedures, collection periods, 

and streamflows during sample measurement and collection. 

Another limitation of the surface-water-quality data available 

for analysis was the dominance of sampling sites along the 

North Canadian River (fig. 16, table 5). Water quality in 

the North Canadian River is of interest to several tribes and 

agencies because it is one of the larger rivers flowing through 

their areas of interest or jurisdiction. The river is downstream 

from many municipal- and industrial-treatment outfalls 

(Esralew and others, 2011a, fig. 1) and is a source of water 

supply for several cities in Oklahoma County (Tortorelli, 

2009). Relatively few sites were sampled on other streams in 

this area, limiting surface-water-quality interpretation in other 

streams in this area.

Tribes and agencies have sampled surface-water quality 

in this area for a variety of reasons, including monitoring 

of general water quality (USGS, the Citizen Potawatomi 

Nation, the Kickapoo Tribe of Oklahoma, and the OWRB); 

monitoring for effects of specific activities, such as petroleum 

production and municipal wastewater discharges (USGS and 

the Oklahoma Corporation Commission); and conducting 

short-term surveys of limited numbers of constituents, such 

as monitoring for fecal-indicator bacteria for several months 

at five sites by the Oklahoma Department of Environmental 

Quality (appendixes 1–6). Such variation in sampling 

programs provides useful data about surface-water quality, but 

interpretation of those data is limited by not being consistent 

in: (1) sampling methods, (2) measurement methods and 

equipment, (3) spatial coverage, (4) temporal coverage, and 

(5) constituents measured.

Water Properties

Water properties include thermal and electrical properties 

of water and measurements of acidity (pH), dissolved gas, and 

total dissolved solids. Water properties summarized in this 

report include dissolved oxygen concentration, pH, specific 

conductance, water temperature, turbidity, biochemical oxygen 

demand, chemical oxygen demand, total dissolved solids, 

hardness, and suspended solids.

Table 4. Properties of aquifers underlying the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma.

[ft, feet; gal/min, gallons per minute; >, greater than] 

Aquifer

Thickness 

range 

(ft)

Well yield 

range 

(gal/min)

Specific 

capacity 

range 

(gal/min/ft)

Alluvial 1,210–100 1,210–>1,000 30.29

Central Oklahoma 1,2450–1,100 1,225–400 40.36–1.3

Vamoosa-Ada 1,2200–800 1,225–300 50.48–1.3

1

Bingham and Moore (1983).

2

Johnson (1983).

3

Davis and Christensen (1981).

4

Parkhurst and others (1996).

5

Abbott and DeHay (2008).
26 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 16. Locations of selected surface-water-quality sampling sites in and near the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma.

Harrah

Base modified from U.S. Geological Survey

National Hydrography Dataset, 2012

Albers Equal-Area Conic projection

North American Datum 1983

Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

97°20' 97°10' 97°00' 96°50' 96°40'

35°40'

35°30'

35°20'

35°10'

35°00'

34°50'

#

#

#

# #

#

##

#

#

#

#

#

#

#

#

#

#

#

#

#

##

#

#

#

#

#

#

#

# #

#

#

#

# #

#

#

#

34

33

32

31

30

29

28

27

26

25 24

23

22

21

19

18

17

13

12

11

10

9

38

16

8

7 6

5

4

37

36

3

2

1

41

42

40

39

Citizen Potawatomi Nation Tribal Jurisdictional Area 

Surface-water quality site and identifier, by agency

 Citizen Potawatomi Nation

 Kickapoo Tribe of Oklahoma

 Oklahoma Corporation Commission

 Oklahoma Department of Environmental Quality

 Oklahoma Water Resources Board

 U.S. Geological Survey

EXPLANATION

O

O

O

O

O

O

28

10

2

1

12

21

Shawnee

Reservoir

§ ̈¦44

§ ̈¦35

§ ̈¦35

§ ̈¦240 § ̈¦40 § ̈¦40

Wes Watkins Reservoir

Lake

 Thunderbird

Stanley

Draper

Lake

Horseshoe

Lake

Little River

Canadian River

North Canadian River

Salt Creek

CREEK COUNTY

SEMINOLE

COUNTY

PONTOTOC

COUNTY

MCCLAIN

COUNTY

GARVIN

COUNTY

CLEVELAND

COUNTY

OKLAHOMA

COUNTY

LOGAN COUNTY

OKFUSKEE

COUNTY

POTTAWATOMIE

COUNTY

LINCOLN

COUNTY
Evaluation of Water-Quality Data 27

Table 5. Names and locations of selected surface-water quality sites and weather stations sampled or measured in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 through 2011.

[Map numbers from figure 17 of this report, sites sharing the same map numbers are colocated, horizontal base for latitudes and longitudes is the North 

American Datum of 1983]

Map 

number Sampling agency Site name

North 

decimal 

latitude

Decimal 

longitude

1 Citizen Potawatomi Nation North Canadian River at Luther Road 35.500 -97.195

1 U.S. Geological Survey North Canadian River near Harrah, Okla. (07241550) 35.500 -97.194

1 Oklahoma Water Resources Board 520510000110-01 35.500 -97.194

2 Citizen Potawatomi Nation North Canadian River at Giverney 14SE 35.426 -97.046

3 Citizen Potawatomi Nation North Canadian River at Knight 21 35.315 -96.893

4 Citizen Potawatomi Nation North Canadian River at Knight 29 35.314 -96.915

5 Citizen Potawatomi Nation North Deer Creek at Firelake Grand Casino 35.382 -97.0561

6 Citizen Potawatomi Nation Squirrel Creek at Tribal Administration Building 35.301 -96.926

7 Citizen Potawatomi Nation Squirrel Creek at Tribal Environmental Office 35.301 -96.919

8 Citizen Potawatomi Nation Un-named tributary to Squirrel Creek 35.294 -96.918

9 Kickapoo Tribe of Oklahoma NCR01 35.572 -97.273

10 Kickapoo Tribe of Oklahoma NCR02 35.544 -97.246

11 Kickapoo Tribe of Oklahoma NCR04 35.432 -97.060

12 Kickapoo Tribe of Oklahoma NCR05 35.391 -97.039

12 Oklahoma Water Resources Board 520510000110-07 35.391 -97.040

12 Oklahoma Department of Environmental Quality NC08 35.391 -97.040

13 Kickapoo Tribe of Oklahoma NCR07 35.321 -96.953

14 National Weather Service Seminole, Okla. 35.233 -96.667

15 National Weather Service Shawnee, Okla. 35.350 -96.900

16 Oklahoma Corporation Commission Blacksmith Creek 35.073 -96.887

17 Oklahoma Corporation Commission Blacksmith Creek tributary 35.044 -96.894

18 Oklahoma Corporation Commission Bruno Creek 35.058 -96.779

19 Oklahoma Corporation Commission Canadian River at U.S. Highway 177 34.965 -96.929

21 Oklahoma Corporation Commission Helsel Creek 35.047 -97.159

22 Oklahoma Corporation Commission Pond Creek 35.030 -97.150

23 Oklahoma Corporation Commission Pond Creek tributary 34.945 -97.116

24 Oklahoma Corporation Commission Popshego Creek 35.080 -96.810

25 Oklahoma Corporation Commission Salt Creek 35.086 -96.813

26 Oklahoma Corporation Commission Wewoka Creek headwater tributary 35.271 -96.789

27 Oklahoma Department of Environmental Quality CW01 35.502 -97.230

28 Oklahoma Department of Environmental Quality NC06 35.595 -97.318

29 Oklahoma Department of Environmental Quality NC07 35.518 -97.230

30 Oklahoma Department of Environmental Quality OC01 35.596 -97.312

31 Oklahoma Water Resources Board 520510000110-02 35.411 -96.789

32 Oklahoma Water Resources Board 520510000110-03 35.411 -96.789

33 Oklahoma Water Resources Board 520510000110-04 35.405 -96.876

34 Oklahoma Water Resources Board 520510000110-05 35.333 -96.869

35 Oklahoma Water Resources Board 520510000110-06 35.400 -96.670

36 Oklahoma Water Resources Board 520510000110-1S 35.405 -96.876

37 Oklahoma Water Resources Board 520800030070-01 35.058 -96.778

38 Oklahoma Water Resources Board 520800030080-01 35.080 -96.810

39 Oklahoma Water Resources Board 520800030120-01 35.073 -96.887

40 U.S. Geological Survey Canadian River at Purcell, Okla. (07229200) 35.014 -97.347

41 U.S. Geological Survey Little River near Tecumseh, Okla. (07230500) 35.173 -96.932

42 Citizen Potawatomi Nation Little River at U.S. Highway 177 35.173 -96.932
28 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Flowing surface water typically has greater than 7 mg/L 

dissolved oxygen concentration because of direct contact with 

oxygen in the atmosphere, photosynthetic emission of oxygen 

by aquatic plants during daylight hours, and turbulent flow 

entraining atmospheric oxygen (Vaccari and others, 2006; 

Drever, 1988). Dissolved oxygen, like other gases, generally 

occurs in lesser concentrations as water temperature increases 

(Hem, 1985). Dissolved oxygen concentration in water is used 

to evaluate whether there is sufficient oxygen available for 

respiration of fish, amphibians, and other aquatic biota; and 

whether organic loading by treated wastewater discharges 

or through eutrophic growth of aquatic plants, which 

compose part of chemical and biological oxygen demand, are 

substantial in a stream (Drever, 1988).

Most surface-water samples collected in this area from 

1985–2011 had dissolved oxygen concentrations greater 

than the lower limits of criteria for coldwater (6.5 mg/L) and 

warmwater (5.5 mg/L) aquatic organisms in ambient waterquality criteria defined by the USEPA (fig. 17; Chapman, 

1986). In two small streams, Squirrel Creek and North 

Deer Creek, 25 to 50 percent of water samples collected 

by the Citizen Potawatomi Nation had dissolved oxygen 

concentrations less than both criteria (fig. 17), indicating 

potential limitation of those streams for aquatic biota caused 

by diminished oxygen concentration. Although there are no 

known discharges of treated wastewater upstream from those 

sampling sites (figs. 17 and 18, table 5), the North Deer Creek 

sampling site is downstream from the Wes Watkins Reservoir 

and water in reservoirs periodically has low dissolved oxygen 

concentrations, particularly in deep water (Vaccari and others, 

2006). Both streams are relatively small and such streams can 

have nearly no flow during parts of the year, which can lead to 

stagnation and lesser dissolved oxygen concentrations.

Most of the surface-water-quality samples described in 

this report were collected during daylight hours. Continuous 

monitoring of dissolved oxygen concentration at the North 

Canadian River near Harrah, Okla., streamflow-gaging station 

and elsewhere indicates periodic lesser concentrations of 

dissolved oxygen (fig. 19) probably caused by cessation of 

photosynthetic oxygen emission at night, and ongoing plant 

and microbial respiration, which consumes dissolved oxygen 

in water. Periodic anoxic conditions can kill aquatic organisms 

and change assemblages of aquatic species and aquatic 

ecosystem function (Ecological Society of America, 2012; 

Egan, 2008). 

The acid or alkaline characteristic of water is denoted by 

pH, with a pH value of 7 being neutral, lesser values being 

increasingly acidic, and greater values being increasingly 

alkaline. Natural waters typically have near neutral pH 

(Hem, 1985), similar to values measured in most surfacewater samples collected in this area (fig. 20). The USEPA 

has set minimum and maximum limits for pH of 6.5 and 

9.0, respectively, both for continuous criteria concentration 

of surface water and secondary drinking-water standards to 

protect the health of aquatic organisms from water that is 

strongly acidic or alkaline, both of which can be corrosive to 

animal tissues, and for aesthetic reasons and minimization of 

metal concentrations in drinking water (U.S. Environmental 

Protection Agency, 2002, 2011b). Only two surface-water 

samples collected from 1985–2011 in the area had pH values 

exceeding (below) the acidic limit of 6.5 (fig. 20). A few 

surface-water samples, primarily collected at sites on the 

North Canadian and Canadian Rivers, had pH values greater 

than the top continuous criteria concentration and secondary 

drinking-water standard of 9.0 (figs. 16 and 20, table 5). 

Values of pH can change substantially and seasonally (fig. 20), 

caused by inputs of groundwater and runoff to the river and 

processes in the river, such as respiration and photosynthesis 

of plants. Differences in pH measured by the three agencies 

sampling at the North Canadian River near Harrah, Okla., 

streamflow-gaging station may have been caused by different 

sampling periods and streamflow conditions when those 

samples were collected (fig. 20).

Specific conductance is an indirect indicator of the total 

amount of soluble substances dissolved in water samples 

denoted by “total dissolved solids.” As with dissolved oxygen 

and pH, specific conductance can substantially change 

diurnally and seasonally (fig. 19), caused by the processes 

previously described for pH. Large concentrations of total 

dissolved solids can cause precipitation of minerals in irrigated 

soils and in water pipelines and appliances and cause a salty 

taste in drinking water. For these reasons, the USEPA set 

a secondary drinking-water standard of 500 mg/L for total 

dissolved solids (U.S. Environmental Protection Agency, 

2011b). At the 22 surface-water sites sampled by the USGS, 

OWRB, Kickapoo Tribe of Oklahoma, and the Oklahoma 

Corporation Commission from 1985–2011, more than 50 

percent of samples had total dissolved solids concentrations 

exceeding the secondary drinking-water standard at all but one 

site (Pond Creek tributary) (fig. 21, table 5). The surface-water 

samples having the largest total dissolved solids concentration 

were collected at sites in the Salt Creek watershed from Bruno, 

Blacksmith, and Popshego Creek in the southeastern part of 

this area (figs. 16 and 21, table 5), with most samples collected 

at those sites having total dissolved solids concentrations 

greater than 1,000 mg/L.
Figure 17. Distribution of dissolved oxygen concentration in surface-water samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Athrough 2011.

CPN North Canadian River at Luther Road (1)

USGS North Canadian River near Harrah, Okla. (1)

OWRB 520510000110–01 (1)

KT NCR05 (12)

OWRB 520510000110–07 (12)

CPN Little River at Highway 177 (42)

CPN unnamed tributary to Squirrel Creek (8)

CPN Squirrel Creek at Tribal Administration Building (6)

CPN Squirrel Creek at Tribal Environmental Office (7)

CPN North Canadian River at Knight 29 (4)

CPN North Canadian River at Knight 21 (3)

OWRB 520510000110–05 (34)

CPN North Deer Creek at FireLake Grand Casino (5)

OWRB 520510000110–06 (35)

OWRB 520510000110–04 (33)

OWRB 520510000110–02 (31)

OWRB 520510000110–03 (32)

CPN North Canadian River at Giverney 14SE (2)

KT NCR02 (10)

KT NCR04 (11)

KT NCR01 (9)

KT NCR07 (13)

Surface-water-quality sampling site

302520

15

10

50

Dissolved oxygen concentration, in milligrams per liter (mg/L)

6.5 mg/L, 30-day mean criteria

for warmwater fish (Chapman, 1986)

5.5 mg/L, 30-day mean criteria for

coldwater fish (Chapman, 1986)

26 342 60 22 8 26 32 30 30 26 31 35 32 9 10 10 8 32 22 14 22 18

x

xxxxx

xx

x

x

x

xx

xx

x

x x x

10

EXPLANA

Schemat Numbe Upper  Upper  Upper  75th pe Media 25th pe Lower  Lower 

Citizen PU.S. GeoOklahomKickapoo North CaSite num

Site names in sicolocated sites.

CPN

USGS

OWRB

KT

NCR

(1)

xx
30 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 18. Locations of National Pollutant Discharge Elimination System permit locations in and near the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, 2012.

Salt Creek

Harrah

Base modified from U.S. Geological Survey Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

National Hydrography Dataset, 2012

Albers Equal-Area Conic projection

North American Datum 1983

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

97°20' 97°10' 97°00' 96°50' 96°40'

35°40'

35°30'

35°20'

35°10'

35°00'

34°50'

Citizen Potawatomi Nation Tribal

 Jurisdictional Area 

National Pollutant Discharge

 Elimination System Permit

 (Oklahoma Department of 

 Environmental Quality, 2012)

EXPLANATION

§ ̈¦44

§ ̈¦35

§ ̈¦35

§ ̈¦240 § ̈¦40 § ̈¦40

Wes Watkins Reservoir

Lake

 Thunderbird

Stanley

Draper

Lake

Horseshoe

Lake

Shawnee

Reservoir

Little River

Canadian River

North Canadian River

CREEK COUNTY

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

MCCLAIN

COUNTY

GARVIN

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

LOGAN COUNTY

OKFUSKEE

COUNTY

POTTAWATOMIE

COUNTY

LINCOLN

COUNTY
Evaluation of Water-Quality Data 31

Figure 19. Water-quality data from continuous monitor at the North Canadian River near Harrah, Oklahoma, streamflow-gaging station, 

October 2007 through September 2011.

2008 2009 2010 2011

Jan. July Jan. July Jan. July Jan. July

Date

Water temperature, in degrees Celsius

0

5

-5

10

15

20

25

30

35

37.5

0

500

1,000

1,500

2,000

pH, in standard units

7.5

8.0

8.5

9.0

10

15

20

22.5

0

5

7.0

Specific conductance, in microsiemens

per centimeter at 25 degrees Celsius

Dissolved oxygen concentration,

in milligrams per liter

EXPLANATION

Continuous data

Period of approved data

Median daily value
Figure 20. Distribution of pH in surface-water samples collected in or near the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1985 

CPN North Canadian River at Luther Road (1) USGS North Canadian River near Harrah, Okla. (1) OWRB 520510000110–01 (1) OWRB 520510000110–07 (12) CPN unnamed tributary to Squirrel Creek (8) CPN Squirrel Creek at Tribal Administration Bldg. (6) CPN Squirrel Creek at Tribal Environmental Office (7) CPN North Canadian River at Knight 29 (4) CPN North Canadian River at Knight 21 (3) OWRB 520510000110–05 (34) CPN North Deer Creek at FireLake Grand Casino (5) OWRB 520510000110–06 (35) OWRB 520510000110–04 (33) OWRB 520510000110–02 (31) OWRB 520510000110–03 (32) CPN North Canadian River at Giverney 14SE (2) KT NCR02 (10) KT NCR01 (9) USGS Little River near Tecumseh, Okla. (41) CPN Little River at Highway 177 (42) USGS Canadadian River at Purcell, Okla. (40)

Surface-water-quality sampling site

pH, in standard units

11

10

98765

Maximum criterion continuous concentration(U.S. Environmental Protection Agency, 2002)

Minimum criterion continuous concentration(U.S. Environmental Protection Agency, 2002)

26 450 60 8 34 26 18 32 30 30 26 31 34 32 9 10 10 8 32 22 18

x

xxxx

x

x

x

xx

xx

x

xx

xx

10

EXPLANA

Schemat Numbe Upper  Upper  Upper  75th pe Median 25th pe Lower  Lower 

Lower 

Citizen PU.S. GeoOklahomKickapoo North CaSite num

Site names in sicolocated sites.

CPN

USGS

OWRB

KT

NCR

(1)

xx
Figure 21. Distribution of total dissolved solids concentration in surface-water samples collected in or near the Citizen Potawatomi Nation Tribal Jur1985 through 2011.

Secondary drinking-water standard = 500 mg/L

(U.S. Environmental Protection Agency, 2011b)

Surface-water-quality sampling site USGS North Canadian River near Harrah, Okla. (1) OWRB 520510000110–01 (1) OWRB 520510000110–07 (12) KT NCR05 (12) OCC Canadian River at Highway 177 (19) OCC Pond Creek Tributary (23) OCC Bruno Creek (18) OWRB 520800030120–01 (39) OCC Blacksmith Creek (16) OWRB 520800030080–01 (38) OCC Popshego Creek (24) KT NCR07 (13) OWRB 520510000110–05 (34) OWRB 520510000110–06 (35) OWRB 520510000110–04 (33) OWRB 520510000110–1S (36) OWRB 520510000110–02 (31) OWRB 520510000110–03 (32) KT NCR04 (11) KT NCR02 (10) KT NCR01 (9) OWRB 520800030070–01 (37)

Total dissolved solids, in milligrams per liter (mg/L)

5,000

10,000

1,000

500100

50

284 60 21 7 9 9 3 3 7 8 5 7 19 35 9 10 3 10 8 22 22 18

xxxxxxxxxx

xx

x

xx

x

x

xxx

x

10

EXPLANAT

Schemati Number  Upper o Upper a 75th per Median 25th per Lower a Lower o Lower dData poin

U.S. GeoloOklahoma Kickapoo North CanOklahoma Site numb

Site names in sim colocated site

USGS

OWRB

KT

NCR

OCC

(1)

xx
34 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Water hardness, expressed as milligrams per liter of 

calcium carbonate, is the sum of milliequivalents per liter 

concentrations of calcium, magnesium, iron, and manganese 

multiplied by 50 (Hem, 1985). Hardness was measured 

primarily in surface-water samples collected from the North 

Canadian River and its tributaries, primarily in the north or 

central part of this area (figs. 16 and 22, table 5). Hardness 

can limit the use of water for some purposes. Hard water 

requires more soap and synthetic detergents for cleaning and 

contributes to buildup of mineral “scale” in boilers and other 

industrial equipment (U.S. Geological Survey, 2011). Water 

can be categorized as being soft (61 to 120 mg/L of hardness), 

moderately hard (121–180 mg/L of hardness), or very hard 

(greater than 180 mg/L of hardness) (U.S. Geological Survey, 

2011). Using these hardness categories, more than 75 percent 

of surface-water samples collected in this area were very hard 

and none were soft (fig. 22). 

Major Ions

Major ions are electrically charged atoms or molecules, 

including calcium, magnesium, sodium, potassium, chloride, 

bicarbonate, and sulfate, that are the principal dissolved 

substances in most natural waters (Hem, 1985). Chloride is 

one of the major ions substantially affecting water quality 

in this area. Much of this area is underlain by groundwater 

having dissolved solids concentrations exceeding 1,000 mg/L, 

with sodium being the predominant cation (positively charged 

ion) and chloride being the predominant anion (negatively 

charged ion) (Bingham and Moore, 1975; Morton, 1986). 

Substances common in brines, particularly sodium and 

chloride, may be derived from solution of salt in the VamoosaAda aquifer, solution of saltbeds in Permian-age units to 

the west of the study area, upwelling of brines caused by 

groundwater pumpage, and drawing up and disposal of brines 

from oil and gas production (Morton, 1986).

Large concentrations of chloride can harm plants, 

including many types of plants used to feed livestock and 

humans (Maas, 1987). Water containing relatively large 

concentrations of sodium and chloride can be problematic 

when used for drinking water or aquatic habitat by humans, 

livestock, and wildlife, contributing salty taste, causing 

elevation in blood pressure (at sodium chloride concentrations 

greater than 2,500 mg/L), and causing other metabolic effects 

(Wesson, 1969; Fadeeva, 1971). Chloride also increases 

corrosivity of water to metal pipes, which can increase 

concentrations of iron, manganese, lead, and copper in 

drinking water (World Health Organization, 1996). For these 

reasons, the USEPA has set a secondary drinking-water 

standard of 250 mg/L and a continuous criterion concentration 

of 230 mg/L for chloride in surface water (U.S. Environmental 

Protection Agency, 2002, 2011b). As with total dissolved 

solids, the greatest concentrations of chloride were measured 

at sites in the Salt Creek watershed in the southeastern part 

of this area (figs. 16 and 23, table 5). Most surface-water 

samples collected from sites in that watershed exceeded the 

secondary drinking-water standard and the criterion continuous 

concentration for chloride (fig. 23).

Nutrients

Compounds of nitrogen and phosphorus are known as 

nutrients in water because they are vital substances for the 

growth of plants, including those that form the base of aquatic 

food chains. Increases of nutrient concentrations in surface 

water lead to increased plant growth (known as eutrophication), 

which can affect ecological and aesthetic qualities of lakes and 

streams. Most freshwater systems are “phosphorus-limited,” 

meaning that they have a lesser proportion of phosphorus to 

nitrogen than typically occurs in plant tissues (Vaccari and 

others, 2006). Additions of phosphorus to such systems through 

disposal of treated wastewater, erosion of sediments from 

streambanks, dredging of streambed sediments, runoff from 

agricultural and urban areas, or contribution from other sources 

can substantially increase growth of aquatic plants. Because of 

the risk of eutrophication, many States have established waterquality standards for total phosphorus concentrations in streams. 

In Oklahoma, a standard of 0.037 mg/L of total phosphorus 

concentration was established to protect water quality and 

aquatic habitat in Scenic Rivers (State of Oklahoma, 2006). 

In Wisconsin, a standard of 0.075 mg/L of total phosphorus 

concentration was established for most streams, with some 

streams having higher standards of 0.200 mg/L (State of 

Wisconsin, 2010).

Most surface-water-quality samples collected in this 

area from 1985–2011 had considerably greater total phosphorus 

concentrations than those standards (fig. 24). All of the surfacewater sites sampled for phosphorus in this area were on the 

North Canadian River, generally to monitor effects on water 

quality and attenuation of upstream urban runoff and discharge 

of treated wastewater (Esralew and others, 2011a). Additional 

monitoring for phosphorus concentration in other streams in 

this area would provide more complete information about the 

occurrence and distribution of phosphorus concentrations in 

surface water. Water-quality data from the North Canadian 

River near Harrah, Okla., streamflow-gaging station, the site 

with the greatest number of paired streamflow measurements 

and nutrient analyses in this area, indicate decreases in 

concentrations of total nitrogen and phosphorus with increasing 

streamflow, up to approximately 1,000 ft3/s, above which a 

few samples indicate that concentrations of these nutrients 

may level off (fig. 25). Total nitrogen and phosphorus 

concentrations generally followed a linear relation (fig. 25). 

Such relations of these nutrient concentrations with streamflow 

and with each other indicate that point sources are substantial 

contributors of these nutrients, with greater streamflows 

diluting nutrient concentrations and similar ratios of these 

nutrients being measured across the recorded range of 

streamflow. Such point sources can include dischargers 

of treated industrial and municipal wastewater, which are 

numerous upstream from this streamflow-gaging station 

(fig. 18).
Figure 22. Distribution of hardness in surface-water samples collected in or near the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahom

Hardness, in milligrams per liter as calcium carbonate

5,0001,000

100

50

USGS North Canadian River near Harrah, Okla. (1)

CPN North Canadian River at Luther Road (1)

OWRB 520510000110–01 (1)

OWRB 520510000110–07 (12)

CPN Little River at Highway 177 (42)

CPN unnamed tributary to Squirrel Creek (8)

CPN Squirrel Creek at Tribal Administration Building (6)

CPN Squirrel Creek at Tribal Environmental Office (7)

CPN North Canadian River at Knight 29 (4)

CPN North Canadian River at Knight 21 (3)

OWRB 520510000110–05 (34)

CPN North Dear Creek at Firelake Grand Casino (5)

OWRB 520510000110–06 (35)

OWRB 520510000110–04 (33)

OWRB 520510000110–02 (31)

OWRB 520510000110–03 (32)

CPN North Canadian River at Giverney 14SE (2)

Surface-water-quality sampling site

21 190 59 8 21 19 19 19 8 21 21 19 10 10 8 21

HardSoft

Very hard

Moderately hard

59

EXPLA

Schem

Num

 Upp Upp Upp 75th  Med 25th  Low

Low

 Low

Site names  colocate

CPN

USGS

OWRB

(5)

CitizU.S. OklaSite 
Figure 23. Distribution of chloride concentration in surface-water samples collected in or near the Citizen Potawatomi Nation Tribal Jurisdictional Athrough 2011.

USGS North Canadian River near Harrah, Okla. (1) OWRB 520510000110–01 (1) OCC Canadian River at Highway 177 (19) OCC Pond Creek (22) OCC Blacksmith Creek Tributary (17) OCC Helsel Creek (21) OWRB 520800030070–01 (37) OCC Bruno Creek (18) OWRB 520800030120–01 (39) OCC Blacksmith Creek (16) OWRB 520800030080–01 (38) OCC Popshego Creek (24) OCC Salt Creek (25) OCC Wewoka Headwaters Tributary (26) OWRB 52050000110–05 (34) OWRB 52050000110–02 (31) Surface-water-quality sampling site

Chlorideconcentration,inmilligramsperliter (mg/L)

10

100

1,000

10,000

100,000

1,000,000

Secondary drinking-water standard = 250 mg/L

(U.S. Environmental Protection Agency, 2011b)

Criterion continuous concentration = 230 mg/L(U.S. Environmental Protection Agency, 2002)

xxxxxxx

x x

224 62 4 4 7 4 3 2 7 7 5 5 4 2 33 10

Injures sensitive plants

Injures most plants (Maas, 1987)

Injures moderately tolerant plants

Safe for all plants

10

EXPLANATI

Schematic 

Number o

 Upper adj 75th perc Median 25th perc Lower ad

Lower out

 Lower detData point—

Site names in sim colocated site

CPN

USGS

OWRB

KT

OCC

(39)

Citizen PoU.S. GeolOklahoma Kickapoo Oklahoma Site numb

x
Figure 24. Distribution of phosphorus concentration in surface-water samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 2011. USGS North Canadian River near Harrah, Okla. (1) USGS North Canadian River near Harrah, Okla. (Dissolved) (1) OWRB 520510000110–01 (1) KT NCR05 (12) OWRB 520510000110–07 (12) KT NCR07 (13) OWRB 520510000110–05 (34) OWRB 520510000110–06 (35) OWRB 520510000110–04 (33) OWRB 520510000110–02 (31) OWRB 520510000110–03 (32) KT NCR04 (11) KT NCR02 (10) KT NCR01 (9) Surface-water-quality sampling site 0

1234

Phosphorus concentration, in milligrams per liter

Oklahoma phosphorus standard for scenicrivers (0.037) (State of Oklahoma, 2006)

Wisconsin phosphorus standard for riversand streams (0.075) (State of Wisconsin, 2010)

123 294 61 24 7 20 35 9 8 10 7 24 23 24

x

xx

x

x

xxxxxx 10

EXPLAN

Schem Num Uppe Uppe Uppe 75th  Med 25th  LoweU.S. GOklahoKickapNorth Site nu

Site names in scolocated site

USGS

OWRB

KT

NCR

(1)
38 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 25. Relations between total nitrogen concentration, total phosphorus concentration, and streamflow in surface-water samples 

collected at the North Canadian River near Harrah, Oklahoma, streamflow-gaging station, 1985 through 2011.

100

Streamflow, in cubic feet per second

50 1,000 10,000 20,000

10

Total nitrogen concentration, in milligrams per liter

0 2 4 6 8 12

Total nitrogen or phosphorus concentration, in milligrams per liter Total phosphorus concentration, in milligrams per liter

20

10

0.1

0

1

2

3

3.5

1

EXPLANATION

Total nitrogen

Total phosphorus
Evaluation of Water-Quality Data 39

Metals

Metals naturally occur in streams and lakes and can be 

increased in concentrations through human activities, such as 

transportation, electric power generation, mining, and waste 

disposal. In sufficient concentrations, metals can be toxic 

to aquatic organisms in streams and lakes and to terrestrial 

organisms such as humans and livestock.

Arsenic is a metal long known to be toxic, having been 

used as a pesticide and poison for hundreds of years (Agency 

for Toxic Substances and Disease Registry, 2007). Because 

of the toxicity of arsenic, the USEPA set a criterion chronic 

concentration of 150 μg/L for this metal for surface water 

(U.S. Environmental Protection Agency, 2002). Arsenic 

concentrations in groundwater exceed the primary drinkingwater standard of 10 μg/L (also known as “parts per billion”) 

in parts of the Central Oklahoma aquifer west of this area 

(U.S. Environmental Protection Agency, 2011a; Smith, 2005; 

Christenson and others, 1998). Arsenic concentration in 1 of 

127 water samples collected at the North Canadian River near 

Harrah, Okla., exceeded the primary drinking-water standard, 

and none of the detected concentrations exceeded the criterion 

chronic concentration for this metal (fig. 26; appendixes 1 and 

5), indicating that arsenic concentrations are unlikely to cause 

notable health problems for humans or aquatic wildlife in the 

upstream part of the North Canadian River in this area, but 

that additional sampling would be needed at other sites in this 

area to extend that conclusion.

Chromium is a metal that naturally occurs in water 

and can come from polluted sites and metal components of 

plumbing systems. Chromium in water typically occurs as 

trivalent or hexavalent ions (Cr+3 or Cr+6). The trivalent form 

of chromium, in small amounts, is a nutrient in the human 

diet (Agency for Toxic Substances and Disease Registry, 

2011a). The hexavalent form of chromium (chromium [VI]) 

is considerably more toxic than the trivalent form, being 

associated with digestive system damage, reproductive 

problems, birth defects, and cancer (Agency for Toxic 

Substances and Disease Registry, 2011a). As of 2011, 

the primary drinking-water standard of 100 μg/L did not 

differentiate between the ionic forms of chromium, but 

toxicologic and epidemiologic data led the State of California 

to establish a public health goal of 0.02 μg/L for chromium 

(VI) in drinking water to minimize long-term risk to public 

health from ingestion of that substance in drinking water 

(California Environmental Protection Agency, 2011). To 

protect aquatic biota from toxic effects of chromium, criterion 

continuous concentrations of 75 and 11 μg/L have been set 

for chromium (III) and chromium (VI), respectively (U.S. 

Environmental Protection Agency, 2002). Chromium has been 

detected in groundwater in parts of the Central Oklahoma 

aquifer, which supplies part of the base flow of most streams 

in this area (Christenson and others, 1998; Reiger, 2010). Only 

a few surface-water samples had chromium concentrations 

exceeding the previously mentioned standards in samples 

collected at the four surface-water sites sampled for chromium 

in this area (fig. 26).

Lead in water can be naturally occurring or associated 

with disposal of lead-acid batteries, combustion of fossil fuels, 

and transportation (Connor and others, 1972; Agency for Toxic 

Substances and Disease Registry, 2011b). Lead has no known 

nutritive values for plants or animals, and ingestion of lead has 

been associated with damage to the brain and central nervous 

system, kidneys, the male reproductive system, the immune 

system, and premature births, with some lead compounds 

being carcinogenic (Kabata-Pendias and Pendias, 1984; 

Canfield and others, 2003; Lin and others, 2003; Lanphear 

and others, 2005; Coon and others, 2006; Agency for Toxic 

Substances and Disease Registry, 2011b). The primary 

drinking-water standards for lead are concentrations of zero 

or nondetect, with a treatment-technique or action level of 

15 μg/L (U.S. Environmental Protection Agency, 2011a). Most 

of the surface-water samples collected in this area had lead 

concentrations less than reporting limits, which ranged from 

0.5 to 100 μg/L (fig. 26). From 5 to 7 percent of the surfacewater samples collected in this area had lead concentrations 

exceeding criterion continuous concentrations set to protect 

aquatic organisms (appendixes 1 and 5). The limited number 

of analyses for lead and large proportions of censored data 

for those samples preclude evaluation of the occurrence and 

distribution of lead in surface water in this area.

Fecal-Indicator Bacteria

Fecal-indicator bacteria are types or species of bacteria 

typically associated with animal feces. Although only a small 

portion of these bacteria may be pathogenic (disease causing), 

they may be associated with a large variety of other pathogenic 

micro-organisms related to animal feces, such as other 

types of pathogenic bacteria (Salmonella sp., Clostridium

sp., and Listeria sp.), protozoans (Giardia sp., Amoeba sp., 

and Cryptosporidium sp.), viruses (Norovirus), and fungi 

(Apsergillus sp., and Histoplasma sp.) (Haack, 2007). Publicwater supplies typically are filtered and disinfected sufficiently 

to prevent transmission of such micro-organisms. Owners 

of private wells and people having recreational contact with 

microbially contaminated water may be more likely to be 

infected by such pathogens. Because of such health risks, a 

primary drinking-water standard of zero total coliform bacteria 

per 100 milliliters (mL) has been set for public-water supplies 

(U.S. Environmental Protection Agency, 2011a) and the State 

of Oklahoma has established primary contact standards to 

protect people in recreational contact with water of monthly 

geometric mean values from at least five samples of 200, 126, 

and 33 colonies per 100 mL for fecal coliform, Escherichia

coli., and enterococci (similar to streptococci) bacteria, 

respectively (State of Oklahoma, 2006). From 10 to 70 percent 

of surface-water samples from nine sites sampled in this area 

from 1985 to 2011 individually exceeded the primary contact 

standard for fecal coliform bacteria (fig. 27) with lesser 

rates of exceedance for Escherichia coli. and greater rates of 

exceedance for enterococci bacteria (appendixes 3 and 5). The 

sites sampled for bacteria were only on the North Canadian 

River, limiting knowledge of the occurrence and distribution 

of these bacteria in other streams in this area.
40 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 26. Distribution of selected metals concentrations in surface-water samples collected in or near the Citizen Potawatomi Nation 

Tribal Jurisdictional Area, Oklahoma, 1985 through 2011.

Surface-water-quality sampling site

USGS North Canadian River 

near Harrah, Okla. (1)

OWRB 520510000110–01 (1)

OWRB 520510000110–02 (31)

USGS North Canadian River 

near Harrah, Okla. (1)

OWRB 520510000110–01 (1)

OWRB 520510000110–02 (31)OWRB 520510000110–05 (34)

USGS North Canadian River 

near Harrah, Okla. (1)

OWRB 520510000110–01 (1)

OWRB 520510000110–02 (31)

OWRB 520510000110–05 (34)

Arsenic concentration, in

micrograms per liter (μg/L)

Chromium concentration, in

micrograms per liter (μg/L) Lead concentration, in micrograms per liter

35

30

25

20

15

10

5

0

0

20

40

60

80

100

120

140

0

20

40

60

80

100

Primary drinking-water standard = 10 μg/L

(U.S. Environmental Protection Agency, 2011a)

Primary drinking-water standard = 100 μg/L

(U.S. Environmental Protection Agency, 2011a)

119 (11) 15 (3) 5 (4) 4 (2)

124 (58) 14 (4) 5 (5) 5 (3)

127 (127) 14 (1) 5 (2)

x

x

xxx

x

x

14 (4)

EXPLANATION

Schematic boxplot

 Number of values—Number of

 censored values in parenthesis

 Lower detached

 Upper outside

 Upper adjacent

 75th percentile

 Median

 25th percentile

 Lower adjacent

Data point—Less than 6 values in data set

 U.S. Geological Survey

 Oklahoma Water Resources Board

Site number on figure 16 and table 5

Site names in similar, nonblack colors are

 colocated sites.

USGS

OWRB

(1)

x
Figure 27. Distribution of fecal coliform bacteria in surface-water samples collected from the North Canadian River in or near the Citizen PotawatomJurisdictional Area, Oklahoma, 1985 through 2011. USGS North Canadian River near Harrah, Okla. OWRB 520510000110–01 OWRB 520510000110–06 DEQ NC08 DEQ CW01DEQ NC07DEQ NC06DEQ OC01 OWRB 520510000110–04 OWRB 520510000110–1S OWRB 520510000110–02 OWRB 520510000110–03 Surface-water-quality sampling site

Fecal coliform bacteria, in colonies per 100 milliliters 10,000 1,000 100

10

1

1,000,000

100,000

Oklahoma Primary Contact Recreation Standard (Geometric mean of

200 colonies per 100 milliliters in five samples collected over 30 days,

State of Oklahoma, 2006)

245 (243) 21 (20) 20 (18) 8 (8) 7 (6) 4 (3) 4 (3) 7 (7) 19 (18) 20 (20) 20 (19) 19 (15)

20 (18)

EXPLANATION

Schematic boxp

Number of val

 censored va Upper outside Upper adjacen 75th percentile Median 25th percentile Lower adjacen

Lower outside

Data point—Les

U.S. Geological SOklahoma Water Oklahoma DeparNorth Canadian 

Site names in similar, no colocated sites.

USGS

OWRB

DEQ

NC
42 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Quality Assurance

The USGS, Kickapoo Tribe of Oklahoma, and OWRB 

compiled data for quality-control samples related to surfacewater-quality samples in the NWIS and STORET databases 

(appendixes 7 and 8). Blank samples collected in the 

jurisdictional area in association with surface-water samples 

did not have detectable concentrations of the major ions 

and nutrients analyzed or had much smaller concentrations 

(typically 10 percent or less) than were measured in field 

water-quality samples (figs. 24–25, 27; appendixes 1 and 7). 

Such differences in data from analyses of field blanks 

compared to field water-quality samples indicated small 

likelihood of contamination of field samples from sampling 

equipment and other environmental factors when the blanks 

were collected. Median relative-percent differences of 

water-quality constituents measured in the field and replicate 

samples generally were less than 25 percent (appendix 8), 

indicating relatively good reproducibility of water-quality 

data. Larger relative-percent differences primarily were 

associated with small numbers near reporting limits, for 

example, a field sample and a replicate sample having 

measured concentrations of a constituent of 0.1 and 0.2, 

respectively, which produce a relative-percent difference of 

66.7 percent but is a relatively small difference in units of 

measurement.

Collection of about 120 replicates and about 95 blanks 

for approximately 1,100 surface-water samples represents 

moderate frequency of quality-control sample collection. 

Generally, each type of quality-control sample is collected 

at frequencies ranging from 5 to 10 percent of the number of 

field water-quality samples, with some of these sample groups 

having larger frequencies of quality-control sample collection 

(appendixes 1, 2, 3, 6, 7, 8, and 9).

Groundwater Quality

Measurement of water properties and concentrations 

of major ions, nutrients, and metals in groundwater can 

provide indications of groundwater recharge rates and flow 

paths, interactions between groundwater and surface water, 

health threats that may be posed by natural or manmade 

compounds in drinking water, and suitability of water for use 

in commercial and industrial processes. Previously published 

reports indicate that groundwater quality in most of this tribal 

jurisdictional area is good (contains less than 500 mg/L of 

dissolved solids), but that an area of approximately 30 square 

miles in the southeastern corner of Pottawatomie County has 

fair to poor water quality (containing greater than 500 mg/L 

or greater than 1,000 mg/L of dissolved solids, respectively) 

(Hart, 1974; Bingham and Moore, 1975).

Water-quality data obtained by sampling 294 wells 

completed in three principal aquifers (alluvial, Central 

Oklahoma, and Vamoosa-Ada) in this area are described in 

this report. Those wells, from which the last samples were 

collected from 1943 to 2005, are distributed relatively evenly 

across the area (fig. 28), with the majority of the sampled 

wells (186) completed in the Central Oklahoma aquifer, 

which underlies the western two-thirds of the area. Depths 

of the wells sampled in the three principal aquifers in the 

area ranged from less than 10 ft to nearly 1,000 ft below 

land surface (fig. 29). Wells completed in alluvial aquifers 

generally were significantly shallower than those completed 

in the Central Oklahoma and Vamoosa-Ada aquifers (fig. 

29). Wells completed in the Vamoosa-Ada aquifer tended 

to be deeper than those completed in the Central Oklahoma 

aquifer but were not deeper at a significance level of 0.05 

of the Wilcoxon rank-sum test (fig. 29). Depending on the 

permeability of soils and aquifer materials, the quality of water 

from shallower wells are more likely to be affected sooner by 

land-surface activities than groundwater that is deep below the 

land surface.

Water Properties

Water properties can indicate chemical reactions 

occurring in aquifers and residence time of groundwater in 

aquifers. For instance, increasing residence time in aquifers 

generally is associated with greater salinity (increased 

concentrations of sodium, potassium, and chloride) (Zouari 

and others, 2011; Cartwright and others, 2012). Lesser 

concentrations of dissolved oxygen also may be associated 

with greater residence time or contact with organic substances 

in soils and aquifer materials. Greater acidity (lesser pH) 

can be associated with increased concentrations of many 

metals in groundwater and greater corrosivity of water. Some 

metals, such as arsenic, chromium, selenium, and uranium, 

can occur in greater concentrations in groundwater having 

alkaline pH in the Central Oklahoma aquifer (Parkhurst and 

others, 1994).

Groundwater in the area generally is well oxygenated 

(fig. 30, appendix 9), though pumps and pressure tanks in 

sampled wells may have introduced some of the dissolved 

oxygen measured in those water samples. Water in the 

Central Oklahoma aquifer had significantly greater dissolved 

oxygen concentration than water in alluvial aquifers (fig. 30). 

Greater dissolved oxygen concentration in water in the 

Central Oklahoma aquifer may be attributable to greater 

organic carbon concentrations in alluvial aquifer materials 

that cause oxygen consumption through aerobic metabolism 

of microbiota or greater oxygenation caused during pumping 

from the generally deeper wells completed in the Central 

Oklahoma aquifer (figs. 29 and 30). Dissolved oxygen 

concentration in water from wells completed in the VamoosaAda aquifer spanned the range of both the alluvial and Central 

Oklahoma aquifers (fig. 30).

The pH measured in groundwater samples generally was 

near neutral. However, 20–25 percent of the samples collected 

from alluvial aquifers and the Central Oklahoma aquifer 

were more acidic than the secondary drinking-water standard 

of 6.5 set by the USEPA to minimize corrosion of pipes in 

water distribution systems and indirectly to reduce metals 

concentrations in drinking water (fig. 30, appendix 9, U.S. 

Environmental Protection Agency, 2011a, 2011b).
Evaluation of Water-Quality Data 43

Figure 28. Principal aquifers and locations of sampled wells in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma.

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

Wes Watkins Reservoir

Lake

 Thunderbird

Stanley

Draper

Lake

Horseshoe

Lake

Shawnee

Reservoir

Salt Creek

Little River

Canadian River

North Canadian River

Base modified from U.S. Geological Survey digital data, 1983, 1:100,000

Albers Equal-Area Conic projection

North American Datum of 1983

Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

Aquifer boundaries from Oklahoma Water Resources Board, 2011

97°20' 97°10' 97°00' 96°50' 96°40'

35°30'

35°20'

35°10'

35°00'

Aquifer

 Alluvial

 Central Oklahoma

 Vamoosa-Ada

Citizen Potawatomi Nation Tribal

 Jurisdictional Area boundary

EXPLANATION

Sampled well, by aquifer

 Alluvial

 Central Oklahoma

 Vamoosa-Ada

#

#
44 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Specific conductance, an indirect measurement 

of dissolved ionic constituents in water (Hem, 1985), 

generally ranged from approximately 100 to as much as 

5,000 microsiemens per centimeter at 25 degrees Celsius 

in water samples collected from the three principal aquifers 

in this jurisdictional area from 1947 through 2004 (fig. 30, 

appendix 9). Specific conductance was significantly greater 

in the 22 water samples collected from the Vamoosa-Ada 

aquifer than in water samples collected from alluvial and 

Central Oklahoma aquifers in the area (fig. 30), which may be 

related to differing mineralogies and greater depths below land 

surface being associated with greater residence time of water 

in the Vamoosa-Ada aquifer (fig. 30).

Dissimilar from specific conductance, total dissolved 

solids concentrations were smallest in 32 water samples 

collected from the Central Oklahoma aquifer compared to 

those measured in samples collected from the alluvial and the 

Vamoosa-Ada aquifers in the area (fig. 30). The much smaller 

number of samples analyzed for total dissolved solids than 

for specific conductance may have skewed the total dissolved 

substances data for these aquifers.

Similar to specific conductance, alkalinity was similar 

in water samples collected from the alluvial and Central 

Oklahoma aquifers, with water samples collected from the 

Vamoosa-Ada aquifer having significantly greater alkalinity 

(fig. 30). If bicarbonate is a major component of both 

alkalinity and dissolved solids in these aquifers, which is not 

uncommon, then alkalinity concentrations would have similar 

relations between sampled aquifers as specific conductance, 

which is an indirect measurement of dissolved ionic substance 

concentration.

Hardness of water samples collected from these three 

aquifers generally was “very hard,” similar to hardness 

measured in surface water in this area (figs. 23 and 30). 

Water samples from wells completed in alluvial aquifers 

and the Central Oklahoma aquifer typically were very hard 

(fig. 30), though some samples from both aquifers were soft. 

Approximately 30 percent of the water samples collected from 

the Vamoosa-Ada aquifer, however, were soft (hardness less 

than or equal to 60 mg/L as calcium carbonate).

Major Ions

Concentrations and proportions of major ions can 

indicate different: (1) sources of groundwater, (2) chemical 

properties of aquifer materials, and (3) residence times of 

water along groundwater flow paths and chemical properties 

of aquifer materials along flow paths. Major ions are readily 

and inexpensively analyzed and provide similar answers 

to contaminant sources that can be provided by much 

more expensive isotopic and organic-chemical analyses 

(Schlottmann and others, 2000).

Calcium is an abundant element in carbonate and silicate 

rocks that typically occurs as a divalent cation (Ca+2) in water 

(Hem, 1985). Although calcium concentrations tended to 

decrease, in order, from the alluvial to the Central Oklahoma 

to the Vamoosa-Ada aquifer (figs. 31 and 32), calcium 

concentrations were not significantly different between the 

aquifers. 

Figure 29. Distribution of depths of wells sampled from 1943 through 2005 by aquifer in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma. 

A

B

B

85 186 23

x

x

x x

x

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

3

10

100

1,000

Well depth, in feet below land surface

B

186

EXPLANATION

Constituent distributions with the 

 same letter are not significantly 

 different (p-value of the Wilcoxon

 rank-sum test less than or equal to

 0.05)

Number of values

Upper outside

Upper adjacent

75th percentile

Median

25th percentile

Lower adjacent

Lower outside

x

x
Evaluation of Water-Quality Data 45

Figure 30. Distribution of values of selected water-quality constituents and properties by aquifer in groundwater samples collected in 

the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1943 through 2011.

Hard

Soft

Very hard

Moderately hard

A

B

B

A

A

A A

A

A

B

B

A, B

B

A A

85 154 22

34 136 11

8 32 11 40 170 (3) 23

80 162 22

40 173 23

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

8

6

10

2

0

4

12

100

50

1,000

10,000

100

10

1

1,000

10,000

100

30

1,000

10,000

100

20

1,000

Specific conductance, in microsiemens

per centimeter at 25 degrees Celsius Dissolved oxygen, in milligrams per liter

Total dissolved solids, evaporated at

180 degrees Celsius, in milligrams per liter

pH, in standard units

Hardness, in milligrams per liter

as calcium carbonate

Alkalinity, in milligrams per liter

as calcium carbonate

11

10

9

8

7

6

5

A

170 (3)

EXPLANATION

Constituent distributions with the 

 same letter are not significantly 

 different (p-value of the Wilcoxon

 rank-sum test less than or equal to

 0.05)

Number of values—Number of censored

 values in parenthesis

Upper outside

Upper adjacent

75th percentile

Median

25th percentile

Lower adjacent

Lower outside

x

x

Secondary drinking water standards = 6.5 and 8.5

(U.S. Environmental Protection Agency, 2011b)
46 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 31. Distribution of concentrations of major ions in groundwater samples collected in the Citizen Potawatomi Nation Tribal 

Jurisdictional Area, Oklahoma, 1943 through 2005.

Secondary drinkingwater standard =

250 mg/L

Secondary drinkingwater standard =

250 mg/L

Reporting limit =

2 mg/L

Reporting limit =

0.1 mg/L

Secondary drinking-water standard 

(U.S. Environmental Protection Agency, 2011b)

A

B

A A A

A A

B

A A

B

A A

A A

A

A A

B

A A

A

A B

18 85 (8) 10

36 153 20

24 57 5

20 (1) 63 (9) 5

24 83 (7) 12

36 134 20

32 153 21

40 (1) 175 (42) 22 (1)

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

1

10

100

1,000

0.1

1

10

20

Calcium concentration,

in milligrams per liter

0.1

1

10

100

300

Magnesium concentration,

in milligrams per liter

3

10

100

1,000

3,000

Sodium concentration,

in milligrams per liter

20

100

1,000

2,000

Bicarbonate concentration,

in milligrams per liter

1

10

100

1,000

Chloride concentration,

in milligrams per liter (mg/L)

Potassium concentration,

in milligrams per liter (mg/L)

0.1

0.03

1

10

Fluoride concentration,

in milligrams per liter (mg/L)

0.1

1

10

100

1,000

10,000

Sulfate concentration,

in milligrams per liter (mg/L)

A

63 (9)

EXPLANATION

Constituent distributions with the 

 same letter are not significantly 

 different (p-value of the Wilcoxon

 rank-sum test less than or equal to

 0.05)

Number of values—Number of censored

 values in parenthesis

Upper detached

Upper outside

Upper adjacent

75th percentile

Median

25th percentile

Lower adjacent

Lower outside

Lower detached

Data point—Less than 6 values in data set 

x

x
Evaluation of Water-Quality Data 47

Magnesium also is dissolved in water as a divalent 

cation (Mg+2) and like calcium is associated with dissolution 

of carbonate and silicate rocks (Hem, 1985). Similar to 

calcium, the distributions of magnesium concentrations were 

not significantly different between water samples collected 

from the three aquifers, but slightly lesser magnesium 

concentrations were measured in water samples collected from 

the Vamoosa-Ada aquifer (fig. 31).

Potassium and sodium occur as monovalent cations (K+

and Na+) in water and are derived from dissolution of igneous 

rocks and from connate (fossil) water that may be in rocks 

deposited in marine environments (Hem, 1985). At several 

hundred feet below the land surface, the area is underlain by 

water that has increasing dissolved-solids content (salinity) 

with depth (Bingham and Moore, 1975). Consistent with 

greater depth of sampled wells completed in the VamoosaAda aquifer, potassium and sodium concentrations were 

significantly greater in water samples collected from that 

aquifer than in the samples collected from the alluvial and 

Central Oklahoma aquifers (figs. 29 and 31). In this area, the 

base of freshwater (defined as containing less than 5,000 mg/L 

dissolved solids) ranges from as shallow as 300 ft to greater 

than 900 ft below land surface (Hart, 1966). Progression from 

waters relatively enriched in calcium and magnesium to waters 

enriched in potassium and sodium may be associated with 

longer residence times in deeper groundwater (figs. 32 and 33; 

Zouari and others, 2011; Cartwright and others 2012), but also 

may have been caused by local upward seepage of brines and 

brine spills associated with petroleum production (Morton, 

1986). Relations between groundwater quality and well depth 

were not definitive (figs. 29, 31, and 33). Some water-quality 

constituents and physical properties, such as sodium in the 

Vamoosa-Ada aquifer and dissolved solids in alluvial aquifers, 

generally increased with well depths, indicating possible 

increases in sodium and dissolved solids concentrations along 

flow paths in those aquifers.

Figure 32. Proportions of major ions by aquifer in groundwater samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional 

Area, Oklahoma, 1943 through 2005.

Calcium plus magnesium

PERCENT

Sulfate

PERCENT

Calcium Chloride

100

80

60

40

20

0 0

20

40

60

80

100

Magnesium

100

80

60

40

20

0

100

100

80

60

0

20

40

0

20

40

60

80

100

80

40

20

60

100

100

80

60

40

20

0

0

20

40

60

80

100

80

60

40

20

100

20

40

60

80

0

Carbonate plus bicarbonate

Sodium plus potassium

Sulfate plus chloride

PERCENT

EXPLANATION

Alluvial aquifer

Central Oklahoma aquifer

Vamoosa-Ada aquifer
48 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Figure 33. Concentrations of selected water-quality constituents and properties with depth below land surface in groundwater 

samples collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1943 through 2005. 

Specific conductance in water samples from the Vamoosa-Ada

aquifer, in microsiemens per centimeter at 25 degrees Celsius

Sodium concentration in water samples from the Vamoosa-Ada

aquifer, in milligrams per liter

Total dissolved solids dried at 180 degrees Celsius

in water samples from alluvial aquifers, in milligrams per liter

1 10 100 1,000 10,000

100 1,000 10,000

0 200 400 600 800

Well depth, in feet below land surface

10

100

1,000

10

100

1,000

0

40

80

120

160
Evaluation of Water-Quality Data 49

Bicarbonate (HCO3

-

) is an anion derived from dissolution 

of carbonate rocks and oxidation of organic matter in aquifers 

(Hem, 1985). Similar to potassium and sodium, bicarbonate 

concentration and proportion were significantly greater in 

water samples from the Vamoosa-Ada aquifer than in samples 

from the alluvial and Central Oklahoma aquifers (figs. 31 

and 32, appendix 9). Water in all three aquifers ranges from 

calcium-magnesium-bicarbonate dominated water to water 

with greater proportions of sulfate and chloride, perhaps 

associated with greater depths and residence times (fig. 32).

Chloride (Cl-) and fluoride (F-) are anions derived from 

dissolution of igneous rocks and connate seawater in rocks 

deposited in marine environments (Hem, 1985). Although 

chloride concentration tended to be slightly greater in 

water samples from the Vamoosa-Ada aquifer than in water 

samples from the alluvial and Central Oklahoma aquifers, 

those differences were not significant at an alpha level less 

than 0.05 (fig. 31). Similar to bicarbonate, potassium, and 

sodium, fluoride concentrations were significantly greater 

in water samples from the Vamoosa-Ada aquifer than the 

alluvial and Central Oklahoma aquifers in this area (fig. 31). 

Approximately 10 percent of samples from the alluvial and 

Central Oklahoma aquifers and approximately 20 percent 

of samples from the Vamoosa-Ada aquifer exceeded the 

secondary drinking-water standard of 250 mg/L for chloride 

(U.S. Environmental Protection Agency, 2011b).

Sulfate (SO4

-2) is a divalent anion associated with 

dissolution of igneous rocks, gypsum, and oxidation of 

metallic sulfide minerals and organic matter in aquifers 

(Hem, 1985). Similar to chloride, sulfate concentrations 

were generally greater in water samples from the VamoosaAda aquifer and less in water samples from the alluvial and 

Central Oklahoma aquifers (fig. 31). Unlike chloride, the 

concentration of sulfate was significantly less in water samples 

collected from the Central Oklahoma aquifer than in the other 

two principal aquifers in the area, perhaps because of lesser 

amounts of sulfate minerals in the aquifer or binding of sulfate 

in barite deposits common in the Central Oklahoma aquifer 

(fig. 31; Christenson and others, 1998). Similar to chloride, 

approximately 10 percent of samples from the alluvial and 

Central Oklahoma aquifers and approximately 20 percent 

of samples from the Vamoosa-Ada aquifer exceeded the 

secondary drinking-water standard of 250 mg/L for sulfate 

(U.S. Environmental Protection Agency, 2011b).

Nutrients

Nutrients in groundwater are not directly associated 

with increased plant growth, which occurs in surface water, 

but because groundwater provides base-flow seepage of 

water to streams and lakes, increased concentrations of 

nutrients in groundwater can affect the quality of adjoining 

surface water and the suitability of surface-water bodies for 

recreational purposes. Although small concentrations of nitrate 

support the growth of plants and animals, concentrations 

of nitrate-nitrogen (NO3

-

-N) exceeding the primary 

drinking-water standard of 10 mg/L have been associated 

with health problems in humans and livestock, including 

methemoglobinemia (also known as “blue-baby” syndrome) 

(Kross and others, 1993; Bruning-Fann and Kaneene, 1993), 

and increased rates of stillbirth, low birth weight, slow weight 

gain, and death in cattle (National Research Council, 1972). 

Of the 59 water samples from the Central Oklahoma aquifer 

analyzed for nitrate, only 2 exceeded the primary drinkingwater standard. Nitrate concentrations were similar in water 

samples collected from the three aquifers in this area (fig. 34). 

Phosphorus also is a nutrient for plants and animals that 

is associated with eutrophication of surface water. In many 

freshwater bodies, phosphorus is the limiting nutrient for plant 

growth, meaning that small additions of phosphorus can cause 

large increases in plant growth. Because of concerns related to 

eutrophication of Scenic Rivers in Oklahoma, a water-quality 

standard of 0.037 mg/L was set for phosphorus concentration 

in those streams (State of Oklahoma, 2006). Because of a 

relatively high reporting limit of 0.04 mg/L for many of the 

samples, only a few samples (approximately 12 percent of the 

samples collected from the Central Oklahoma aquifer) were 

known to have exceeded that standard (fig. 34). Exceedance 

of that standard in only a few groundwater samples indicates 

that much of the phosphorus in streams in the area is not 

from groundwater seepage, with elevated concentrations 

and loads of phosphorus in surface water more commonly 

being associated with erosion of soils, livestock wastes, and 

resuspension of streambed sediments (Andrews and others, 

2009a).

Metals

Metals occur naturally in aquifer materials and 

groundwater, with some human activities increasing metals 

concentrations in groundwater. Because many metals form 

low-solubility oxide and hydroxide minerals in the presence of 

oxygen, many metals are more likely to be dissolved in water 

with no dissolved oxygen (anoxic conditions) (Elder, 1988).

Arsenic is a semi-metallic element commonly associated 

with iron that occurs in water in the forms of arsenate (As+5

in H2AsO4

-

 or HAsO4

-2) and arsenite (As+3 in HAsO2

) (Hem, 

1985). Arsenic can be dissolved from soils and rocks and 

also is associated with pressure-treated wood and pesticides 

(Agency for Toxic Substances and Disease Registry, 2007). 

In groundwater, arsenic typically is adsorbed to iron oxide 

particles, but pH greater than 8.0 and anoxic conditions 

facilitate desorption of arsenic compounds from those 

solids, increasing arsenic concentrations in water (Hinkle 

and Polette, 1999). Because of the numerous toxic effects 

and carcinogenicity of arsenic, particularly the arsenite form 

of arsenic (Grund and others, 2008), a primary drinkingwater standard of 10 μg/L has been set for arsenic (U.S. 

Environmental Protection Agency, 2011a). Groundwater 

containing arsenic at concentrations greater than that standard 

commonly occur in the western part of the Central Oklahoma 

aquifer, at least 10 miles west of the western boundary of 
50 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

the tribal jurisdictional area (Smith, 2005). None of the 

groundwater samples collected in this area had arsenic 

concentrations exceeding that standard, with the distribution 

of arsenic concentrations being similar between the principal 

aquifers and typically ranging from less than 0.5 to 5 μg/L 

(fig. 35).

Chromium can occur naturally in groundwater and 

also can be found at polluted industrial or commercial sites 

(Hem, 1985; U.S. Environmental Protection Agency, 2011a). 

No groundwater samples collected in the area contained a 

chromium concentration exceeding the primary drinking-water 

standard of 100 μg/L (U.S. Environmental Protection Agency, 

2011a). Most of the samples did not contain detectable 

chromium (fig. 35). As of 2011, the primary drinking-water 

standard did not differentiate between the ionic forms of 

chromium, but the toxicologic and epidemiologic data led 

the State of California to establish a public health goal of 

0.02 μg/L for chromium (VI) in drinking water to minimize 

long-term risk to public health from ingestion of the substance 

in drinking water (California Environmental Protection 

Agency, 2011). To determine if drinking-water supplies in this 

area and elsewhere exceed such small concentrations, smaller 

reporting limits than the 1 μg/L associated with groundwater 

samples collected in this area would be necessary (fig. 35, 

appendix 9).

Iron in groundwater is associated with dissolution 

of minerals in igneous rocks, oxidation of organic matter, 

and contamination at industrial and mining sites. The most 

common type of iron dissolved in groundwater is the divalent 

form known as ferrous iron (Fe+2), with ferric (Fe+3) iron 

occurring in acidic waters (Hem, 1985). In oxic alkaline 

waters, iron generally precipitates in a series of oxide, 

oxyhydroxide, hydroxide, and carbonate minerals. In anoxic 

water containing sulfide, the minerals pyrite and marcasite 

(two forms of FeS) commonly precipitate. Approximately 

10 percent of water samples from the alluvial and Central 

Oklahoma aquifers in this area contained iron concentrations 

exceeding the secondary drinking-water standard of 

250 μg/L, established by the USEPA to minimize metallic 

taste and staining of plumbing fixtures (fig. 35). Although 

water samples collected from the Central Oklahoma aquifer 

appeared to have lesser concentrations of iron than water from 

the other two aquifers, there were no significant differences 

in iron concentrations between the aquifer groups, with most 

of the sample concentrations being censored (nondetects) 

(fig. 35).

Figure 34. Distribution of concentrations of nitrite plus nitrate-nitrogen and dissolved phosphorus by aquifer in groundwater samples 

collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 1943 through 2005.

Primary drinking-water standard

for nitrate as nitrogen = 10 mg/L

(U.S. Environmental

Protection Agency, 2011a)

Reporting limit =

0.04 mg/L

Reporting limit =

0.1 mg/L

A A

A

A B A

15 (3) 59 (9) 1

16 (16)* 98(87) 11 (11)*

x

x

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

0.01

0.1

1

0.01

0.1

1

0.00001

0.0001

0.001

10

100

1,000

Dissolved phosphorus, in milligrams

per liter (mg/L) as phosphorus

Nitrite plus nitrate, in milligrams 

per liter (mg/L) as nitrogen

A

59 (9)

EXPLANATION

Constituent distributions with the same 

 letter are not significantly different 

 (p-value of the Wilcoxon rank-sum 

 test less than or equal to 0.05)

Number of values—Number of censored

 values in parenthesis

Upper outside

Upper adjacent

75th percentile

Median

25th percentile

Lower adjacent

* All samples below the reporting limit

x
Evaluation of Water-Quality Data 51

Figure 35. Distribution of concentrations of selected metals by aquifer in groundwater samples collected in the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, 1947 through 2005.

Reporting limit =

1 μg/L

Reporting limits = 

1, 2, 5, 10,

and 20 μg/L Secondary

drinking-water

standard = 

300 μg/L

Secondary drinkingwater standard = 

50 μg/L

Primary drinking-water standard = 30 μg/L

Reporting limits = 

0.20 and 0.019 μg/L

Reporting limits = 

3, 10, and 100 μg/L

Reporting limits = 

4, 5, and 10 μg/L

Reporting limits = 

0.5, 1, 2,

and 10 μg/L

Reporting limit = 10 μg/L

Reporting limits = 

3, 4, and 10 μg/L

Reporting limits = 4 and 10 μg/L

Secondary drinking-water standard

(U.S. Environmental Protection Agency, 2011b)

Primary drinking-water standard

(U.S. Environmental Protection Agency, 2011a)

A

A

A

A

A A A

A

A A

A

A A

A A

A

A

A

A

A

A

A A

26 99 (1) 18 (1)

31 (6) 124 (22) 11

31 (16) 145 (109) 12 (10)

31 (2) 131 (14) 10

27 (11) 96 (67) 8 (5)

15 (12) 27 (26) 0

31 (21) 136 (88) 11 (7) 0 21 (4) 0

29 (28) 133 (114) 11 (10)

x

x

x

x

x

x

x

x

x

x

x

x

x

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

Vamoosa-Ada

Alluvial

Central 

Oklahoma

Aquifer

Dissolved chromium (VI), in

micrograms per liter (μg/L)

Dissolved lead, in

micrograms per liter (μg/L)

Dissolved manganese, in

micrograms per liter (μg/L)

Dissolved zinc, in

micrograms per liter (μg/L)

50

10

1

0.1

25

20

15

10

5

0

10,000

1,000

100

10

1

0.1

0.01

0.001

0.0001

0.00001

0.000001

10,000

1,000

100

10

1

0.1

Dissolved uranium, in

micrograms per liter (μg/L)

Dissolved lithium, in

micrograms per liter (μg/L)

Dissolved iron, in

micrograms per liter (μg/L)

Dissolved chromium, in

micrograms per liter (μg/L)

Dissolved arsenic, in

micrograms per liter (μg/L)

1,000

100

10

1

0.1

0.01

0.001

200

100

10

3

10,000

1,000

100

10

1

0.1

0.01

0.001

0.0001

100

10

1

0.1

0.01

0.001

0.0001

10

1

0.1

0.01

A

11 (7)

EXPLANATION

Constituent distributions with the same 

 letter are not significantly different 

 (p-value of the Wilcoxon rank-sum 

 test less than or equal to 0.05)

Number of values—Number of censored

 values in parenthesis

Upper detached

Upper outside

Upper adjacent

75th percentile

Median

25th percentile

Lower adjacent

Lower outside

x

x
52 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

The primary drinking-water standards for lead are zero 

(nondetect) with a treatment technique or action level of 15 

μg/L (U.S. Environmental Protection Agency, 2011a). Most 

of the groundwater samples collected in the area from 1987 

through 1989 had lead concentrations less than the reporting 

limit of 10 μg/L, though 1 of the 15 samples collected from 

alluvial aquifers in this area had a lead concentration of 

20 μg/L (fig. 35). The limited number of analyses for lead 

and large number of nondetects preclude evaluation of the 

occurrence and distribution of lead in groundwater in this area.

Lithium concentrations were approximately an order of 

magnitude greater than lead concentrations, with few censored 

values of lithium concentrations in water samples from the 

three aquifers (fig. 35). Lithium is dissolved from lithiumcontaining minerals in igneous rocks and occurs in evaporite 

rocks, such as gypsum, and in natural brines (Hem, 1985). 

Concentrations of lithium greater than 60 μg/L can damage 

some species of trees (Hem, 1985). Symptoms of lithium 

toxicity in humans include gastric distress, dehydration, 

dizziness, weakness, tremors, seizures, and slurred speech 

(National Institutes of Health, 2011). Lithium has been 

prescribed as a mood stabilizer for several decades, with 

therapeutic dosages of 15–20 milligrams per kilogram per 

day (mg/kg/d) of body weight (up to approximately 1,400 

mg/150 pound adult) producing in vivo concentrations slightly 

less than those producing toxic symptoms (Semple, 2005). 

Distributions of lithium concentrations in water samples from 

the three principal aquifers in this area were similar, ranging 

from less than 4 to 140 μg/L (fig. 35, appendix 9). Ingestion 

of 3 liters of water per day at the maximum measured 

concentration of 140 μg/L would provide considerably less 

than therapeutic or toxic doses of this metal.

Manganese commonly is associated with iron in water. 

Like iron, the most common form of manganese is the divalent 

ion (Mg+2) (Hem, 1985). Manganese concentrations were 

similar in water samples collected from the three aquifers in 

the area (fig. 35, appendix 9). The secondary drinking-water 

standard for manganese of 50 μg/L, established primarily 

to minimize metallic taste and black staining of plumbing 

fixtures (U.S. Environmental Protection Agency, 2011b), was 

exceeded in approximately one-third of the water samples 

collected from alluvial aquifers and less than one-fourth of 

the water samples collected from the Central Oklahoma and 

Vamoosa-Ada aquifers in this area (fig. 35, appendix 9). The 

U.S. Environmental Protection Agency (2004) indicates that 

although small amounts of manganese in the human diet 

are nutritive, a secondary drinking-water standard less than 

50 μg/L may be needed to minimize neurologic effects from 

ingestion of the metal in drinking water.

Uranium, a naturally occurring radioactive element 

dissolved from many types of rocks and soils and used 

in some commercial products, is the primary source of 

radioactivity in natural water (Hem, 1985; Agency for 

Toxic Substances and Disease Registry, 2011c). There is 

no known nutritive role for uranium for plants and animals, 

with ingestion of uranium being associated with decreases in 

fertility, kidney damage, and skin damage (Agency for Toxic 

Substances and Disease Registry, 2011c). Although there has 

been no association of cancer with ingestion of water with 

uranium, radiation associated with drinking water containing 

uranium and other radioactive elements has been associated 

with increased incidence of cancer (U.S. Environmental 

Protection Agency, 2011c). Because of negative health effects 

from ingestion of radionuclides such as uranium, the USEPA 

set a primary drinking-water standard of 30 μg/L for uranium 

(U.S. Environmental Protection Agency, 2011b). Of the 124 

water samples analyzed for uranium concentration from the 

Central Oklahoma aquifer and the 11 water samples collected 

from the Vamoosa-Ada aquifer, 5 samples and 1 sample, 

respectively, exceeded the primary drinking-water standard for 

uranium. Those samples were collected in the eastern half of 

the area (fig. 36).

Similar to iron and manganese, zinc is a nutrient for 

plants and animals that typically occurs in water as a divalent 

cation (Zn+2). Zinc can be dissolved from soils and many types 

of rocks and is commonly used in pipe coatings, batteries, and 

alloys (Hem, 1985; Agency for Toxic Substances and Disease 

Registry, 2005). Zinc commonly is associated with lead in 

deposits of metallic sulfides, such as those of the abandoned 

Picher mining district of northeastern Oklahoma (Andrews and 

others, 2009b). Excessive ingestion of zinc can cause digestive 

system distress, anemia, and increased concentrations of 

LDL cholesterol in blood (Agency for Toxic Substances and 

Disease Registry, 2005). A secondary drinking-water standard 

of 5 μg/L (5,000 mg/L) of zinc has been set to minimize 

metallic taste of water (U.S. Environmental Protection 

Agency, 2011b). None of the groundwater samples collected 

in the area had a zinc concentration exceeding that secondary 

drinking-water standard, and the locations of distribution of 

zinc concentration were similar for the three sampled aquifers 

(fig. 35, appendix 9).

Quality Assurance

Collection of quality-control samples, such as replicates 

and blanks, was not common prior to the late 1980s. The 

NWIS database had data for 12 groundwater replicates and 5 

field blanks collected in this area from 1986 through 2004 and 

from 2003 through 2004, respectively. Mean relative-percent 

differences of water-quality constituents measured in the field 

and replicate samples generally were less than 25 percent 

(table 6), indicating relatively good reproducibility of data. 

Larger relative-percent differences primarily were associated 

with small numbers near reporting limits; for example, a field 

sample and a replicate sample having measured concentrations 

of a constituent of 0.1 and 0.2, respectively, that produce 

a relative-percent difference of 66.7 percent, which is a 

relatively small difference in units of measurement.

Blank samples collected in this area in association with 

groundwater samples did not have detectable concentrations 

of the major ions and metals summarized in this report 

(table 7), indicating small likelihood of contamination of field 

samples from sampling equipment and other environmental 

factors when the blanks were collected. Physical properties 

and some metals typically are not measured in field blanks 

(table 7).
Evaluation of Water-Quality Data 53

Figure 36. Locations of sampled wells with uranium concentrations exceeding the primary drinking-water standard in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma.

0 2 4 8 MILES

0 2 4 6 8 KILOMETERS

6

SEMINOLE

COUNTY

POTTAWATOMIE

COUNTY

PONTOTOC

COUNTY

MCCLAIN

COUNTY

CLEVELAND

COUNTY

LINCOLN

COUNTY

OKLAHOMA

COUNTY

Wes Watkins Reservoir

Lake

 Thunderbird

Stanley

Draper

Lake

Horseshoe

Lake

Shawnee

Reservoir

Salt Creek

Little River

Canadian River

North Canadian River

Base modified from U.S. Geological Survey digital data, 1983, 1:100,000

Albers Equal-Area Conic projection

North American Datum of 1983

Tribal jurisdictional area boundary from U.S. Census Bureau, 2000

Aquifer boundaries from Oklahoma Water Resources Board, 2011

97°20' 97°10' 97°00' 96°50' 96°40'

35°30'

35°20'

35°10'

35°00'

Aquifer

 Alluvial

 Central Oklahoma

 Vamoosa-Ada

Citizen Potawatomi Nation Tribal

 Jurisdictional Area boundary

EXPLANATION

Sampled well, by aquifer—Green

 circle indicates uranium

 concentration greater than

 30 micrograms per liter

 Alluvial

 Central Oklahoma

 Vamoosa-Ada

#

#

(

(

(

( (

(

(
54 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Table 6. Relative percent differences of constituents measured in replicate groundwater samples collected in the Citizen Potawatomi 

Nation Tribal Jurisdictional Area, Oklahoma, 2003 through 2004.

[Censored data values computed as being equal to the censoring level, data from U.S. Geological Survey National Water Information System database; mg/L, 

milligrams per liter; μg/L, micrograms per liter; relative percent differences in percent; Dissolved, concentration of a constituent after filtration through a 

0.45 micron pore-size filter]

Water-quality constituent Number of 

samples

Range of 

relative percent 

difference values

Mean relative 

percent 

difference

Physical properties

Dissolved oxygen concentration, in mg/L 3 0 0

pH, in standard units 12 0–9.40 2.30

Specific conductance, in microsiemens per centimeter at 25 degrees Celsius 12 0–120 18.9

Water temperature, in degrees Celsius 3 0 0

Dissolved solids, dried at 180 degrees Celsius, in mg/L 2 0 0

Hardness, in mg/L as calcium carbonate 9 1.59–68.7 25.7

Major ions

Dissolved calcium, in mg/L 11 0–179 19.7

Dissolved magnesium, in mg/L 12 0–75.0 20.0

Dissolved potassium, in mg/L 12 0–40.0 9.03

Dissolved bicarbonate, in mg/L 9 1.75–38.4 14.8

Dissolved sodium, in mg/L 12 0–94.3 18.3

Dissolved chloride, in mg/L 11 0–83.3 18.0

Dissolved fluoride, in mg/L 12 0–58.8 12.1

Dissolved sulfate, in mg/L 12 0–194 36.6

Nutrient

Nitrate plus nitrite, in mg/L as nitrogen 12 0–185 78.3

Metals

Dissolved arsenic, in mg/L 3 0 0

Dissolved, chromium, in μg/L 12 0–18.2 1.5

Dissolved chromium VI, in μg/L 1 66.7 66.7

Dissolved iron, in μg/L 12 0–182 74.9

Dissolved lithium, in μg/L 1 106 106

Dissolved lead, in μg/L 1 0 0

Dissolved manganese, in μg/L 10 0–165 65.9

Dissolved uranium, in μg/L 1 0 0

Dissolved zinc, in μg/L 3 0 0
Data Gaps 55

Collection of only 12 replicates and 5 blanks for 294 

wells sampled is a small frequency of quality-control sample 

collection, with collection of the quality-control samples 

having been done toward the end of the sampling period 

described in this report. Since 1990, each type of qualitycontrol sample typically has been collected at frequencies 

ranging from 5 to 10 percent of the number of field waterquality samples, an issue to be considered for future sampling 

programs.

Data Gaps

Gaps in data coverage temporally, spatially, and in 

measured physical properties and constituents produce an 

incomplete, and in some areas, insufficient measure of the 

quantity and quality of available water resources in the tribal 

jurisdictional area. Some of the major gaps in hydrologic data 

for the area are apparent after review of existing data, and 

means of filling the gaps include:

1. There is a lack of information about streamflow and 

groundwater levels caused by having only four longterm streamflow-gaging stations and no long-term 

groundwater-level measurement network. If the Citizen 

Potawatomi Nation is interested in improving monitoring 

of streamflow, installation of at least one additional 

streamflow-gaging station on the Canadian River in 

the southeastern part of the jurisdictional area would 

be useful. A groundwater-level monitoring network of 

20 wells per principal aquifer, measured at least once 

per year during low water pumpage in the winter, would 

provide information about groundwater flow direction 

and depth to groundwater that currently is not being 

collected. Having continuous water-level monitoring by 

pressure transducers installed in wells in areas of special 

interest would provide information about response of 

local groundwater levels to climatic patterns and seasonal 

pumpage and long-term trends in groundwater levels in 

selected areas of the jurisdictional area.

2. The available data provide limited information about 

surface-water quality, as most surface-water-quality 

sampling has been done in the North Canadian River 

with relatively little sampling of other rivers and streams. 

Periodic water-quality sampling, such as 10–12 times 

per year, at additional sites for greater numbers of 

Table 7. Constituent concentrations measured in blank samples associated with groundwater samples collected in the Citizen 

Potawatomi Nation Tribal Jurisdictional Area, Oklahoma, 2003 through 2004.

[Data from U.S. Geological Survey National Water Information System database; mg/L, milligrams per liter; <, less than; μg/L, micrograms per liter; relative 

percent differences in percent; Dissolved, concentration of a constituent after filtration through a 0.45 micron pore-size filter]

Water-quality constituent Number of samples Range of values Mean value

Physical properties

Dissolved solids, dried at 180 degrees Celsius, in mg/L 5 <10 <10

Major ions

Dissolved calcium, in mg/L 5 <1 <1

Dissolved magnesium, in mg/L 5 <1 <1

Dissolved potassium, in mg/L 5 <1 <1

Dissolved sodium, in mg/L 5 <1 <1

Dissolved chloride, in mg/L 5 <10 <10

Dissolved fluoride, in mg/L 5 <1 <1

Dissolved sulfate, in mg/L 5 <10 <10

Nutrient

Nitrate plus nitrite, in mg/L as nitrogen 5 <0.05 <0.05

Metals

Dissolved arsenic, in mg/L 5 <2 <2

Dissolved, chromium, in μg/L 5 <10 <10

Dissolved iron, in μg/L 5 <10 <10

Dissolved manganese, in μg/L 5 <10 <10

Dissolved zinc, in μg/L 5 <10 <10
56 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

water-quality constituents across local ranges of 

streamflow would provide more comprehensive 

understanding of surface-water quality across the 

jurisdictional area; the effects of local land uses, geologic 

settings, and streamflow conditions on water quality; and 

would provide the ability to reliably determine loads and 

yields of selected constituents through regression relations 

and evaluate areas producing anomalous amounts of 

selected constituents.

3. There is a lack of knowledge in trends of groundwater 

quality and recent groundwater quality based on 

limited sampling periods and distribution of sampled 

wells. Consistent annual sampling for a relatively large 

number of water-quality constituents of a network of 

20 or more wells per major aquifer distributed across 

the jurisdictional area would provide the ability to 

consistently characterize the quality of groundwater and 

to eventually determine trends in groundwater quality 

across the area.

4. There has been a lack of consistent collection of water 

properties and constituents by different agencies across 

the jurisdictional area. With limited budgets and different 

priorities, lack of consistent data collection by different 

agencies probably will continue into the future. However, 

coordination of water-quality sampling among agencies 

would establish goals for properties and constituents to be 

measured in water resources in the area and would help 

to provide more robust data for characterization of local 

water quality. Collection of continuous streamflow data in 

conjunction with collection of surface-water-quality data 

would be useful for investigating relations between waterquality property values and constituent concentrations 

and streamflow as well as providing means to better 

investigate effects of seasons on surface-water quality. 

To the extent that budgets allow, collection for additional 

“nontraditional” water-quality constituents, such as 

emerging contaminants (pharmaceuticals, household 

chemicals, and some pesticides) would enable better 

determination of the effects of wastewater discharges 

from wastewater-treatment plants and onsite septic 

systems on the quality of surface water and groundwater 

in this area.

Summary

The Citizen Potawatomi Nation Tribal Jurisdictional 

Area, comprising approximately 960 square miles in parts 

of three counties in central Oklahoma, has an abundance of 

water resources, being bordered by two major rivers (North 

Canadian and Canadian), having several smaller streams, and 

being underlain by three principal aquifers (alluvial, Central 

Oklahoma, and Vamoosa-Ada). The area periodically is 

subject to flooding and drought, which may limit available 

water resources, particularly during the summer when water 

use increases and streamflows can decrease substantially. This 

report summarizes existing water-use, climatic, geographic, 

hydrologic, and water-quality data and describes several 

means of filling gaps in hydrologic data for this area.

Approximately 115,000 people estimated to live in this 

area used 4.41 million gallons of fresh groundwater, 12.12 

million gallons of fresh surface water, and 8.15 million 

gallons of saline groundwater per day in 2005. Approximately 

8.48, 2.65, 2.24, 1.55, 0.83, and 0.81 million gallons per 

day of water were used for domestic, livestock, commercial, 

industrial, crop irrigation, and thermoelectric purposes, 

respectively. Approximately one-third of the water withdrawn 

in this area in 2005 was saline water produced during 

petroleum production. Future increases in use of freshwater 

in this area will be affected by changes in population and 

changes in agricultural practices. Changes in saline water use 

largely will be affected by future petroleum production.

Land cover in this area is primarily grassland, pasture/

hay fields, and deciduous forest, in a dominantly rural setting. 

Such lack of urban development may limit water-quality 

effects from human activities. Much of the water in the area 

is of good quality, though water quality is impaired in some 

areas by very hard surface water and groundwater; large 

chloride concentrations in some of the smaller streams in the 

southeastern part of the area; relatively large concentrations 

of nutrients and counts of fecal-indicator bacteria in the North 

Canadian River; and chloride, iron, manganese, and uranium 

concentrations that exceed primary or secondary drinkingwater standards in samples from a small number of wells.

Substantial amounts of hydrologic and water-quality data 

have been collected in and near this area, but gaps in those 

data remain, including:

1. Lack of continuous information about streamflow and 

groundwater levels caused by having only four longterm streamflow-gaging stations and no long-term 

groundwater-level measurement network,

2. Limited knowledge of streamflow and surface-water 

quality because most surface-water quality sampling has 

been done in the North Canadian River,

3. Lack of knowledge of patterns and trends of 

concentrations of surface-water-quality constituents 

because of lack of sampling at high-flow and low-flow 

conditions over time,

4. Lack of groundwater quality and recent groundwaterquality data based on limited sampling periods, and

5. Lack of consistent collection of water-quality constituents 

by different Tribes and agencies in and near the area.

These data gaps largely would be filled by:

1. Establishing additional long-term streamflow-gaging 

stations to measure streamflow and as sites for waterquality measurements as streams enter and leave this 

jurisdictional area,
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2. Sampling streams at low-flow and high-flow conditions 

10–12 times per year at selected surface-water-quality 

sites to develop reliable regression relations of changes of 

water quality with streamflow, and

3. Establishing a network of at least 20 wells per principal 

aquifer in this area from which annual measurements of 

groundwater levels and water quality could be made.

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U.S. Geological Survey, 2012c, USGS groundwater data for 

Oklahoma: U.S. Geological Survey, accessed June 2012, at 

http://waterdata/usgs/gov/ok/nwis/gw.

U.S. Geological Survey, 2012d, USGS water-quality data for 

Oklahoma: U.S. Geological Survey, accessed January 2012, 

at http://waterdata.usgs.gov/ok/nwis/qw/.

U.S. Geological Survey, 2013, Environmental impacts 

associated with disposal of saline water produced during 

petroleum production—Osage-Skiatook Petroleum 

Environmental Research Project: U.S. Geological Survey, 

accessed January 15, 2013, at http://toxics.usgs.gov/sites/

ph20_page.html.

Vaccari, D.A., Strom, P.F., and Alleman, J.E., 2006, 

Environmental biology for engineers and scientists: 

Hoboken, New Jersey, John Wiley and Sons, Inc., 931 p.

Wesson, L.G., 1969, Physiology of the human kidney: New 

York, Grune and Stratton, 719 p.

Wilcoxon, Frank, 1945, Individual comparisons by ranking 

methods: Biometrics Bulletin, v. 1, no. 6, p. 80–83.

World Health Organization, 1996, Guidelines for drinkingwater quality (2d ed.), v. 2: World Health Organization 

WHO/SDE/WSH/03.04/03, 94 p.

Zouari, Kamel, Trabelsi, Rim, and Chkir, Najiba, 2011, Using 

geochemical indicators to investigate groundwater mixing 

and residence time in the aquifer system of Djeffara of 

Medenine (southeastern Tunisia): Hydrogeology Journal, 

v. 19, no. 1, p. 209–219. 
62 Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation

Glossary

aquatic Life forms or substances in water.

aquifer A geologic formation, group of formations, or part 

of a formation that contains sufficient saturated permeable 

material to yield large quantities of water to wells and springs 

(New Mexico Office of State Engineer, 1999).

base flow Streamflow derived from ground-water seepage, 

synonymous with “low flow”.

climate The sum total of the meteorological elements 

that characterize the average and extreme condition of the 

atmosphere during a long period of time at any one place or 

region of the earth’s surface (Langbein and Iseri, 1960).

concentration The mass of a substance dissolved per unit 

volume of liquid or contained in a unit mass of solid.

criterion A number or narrative statement assigned to protect 

a designated beneficial use. A water-quality standard set by the 

state.

cubic feet per second A unit expressing rates of discharge. 

One cubic foot per second is equal to the discharge of a stream 

of rectangular cross section, one foot wide and one foot deep, 

with water flowing at an average velocity of one foot per 

second (Langbein and Iseri, 1960). 

ecosystem A natural unit including all life forms and nonliving physical elements that function together.

eutrophication Nutrient enrichment (particularly of 

nitrogen and phosphorus) in aquatic ecosystems that leads 

to increased productivity, including excessive growth of 

algae and other aquatic plants (Graham and others, 2008). 

Excessive eutrophication changes aquatic habitat by changes 

in dissolved oxygen concentration, water temperature, 

availability of spawning beds, and visibility for predator fish. 

Aesthetic effects of hypereutrophication include degradation 

of water quality for swimming and other recreational activities 

and increases in concentrations of taste-and-odor-producing 

organic compounds in drinking water.

gage A device used to measure and record the elevation 

of water in a stream or lake in a semi-continuous manner. 

In a flowing stream, comparisons of measured streamflows 

to surface-water elevations are used to estimate streamflow, 

commonly at 15-minute intervals.

load The mass of a substance flowing past a given point in a 

stream per unit of time, derived from multiplying streamflow 

by the aqueous concentration of a substance by unit correction 

factors. Loads are typically expressed in pounds or kilograms 

per day.

milliequivalents per liter (meq/L) The amount of material 

that will release or react with a millimole of electrical charges 

on particles such as OH-, H+, or electrons. Milliequivalents 

per liter are computed by multiplying the concentration of an 

ionic substance by the atomic mass of the ionic substance and 

the charge of the ion.

milligrams per liter (mg/L) Milligrams of a substance 

dissolved in one liter of water, that is the same as a part per 

million in freshwater because one liter of distilled water 

weighs one million milligrams (one kilogram). 

nutrient An element such as nitrogen or phosphorus needed 

for growth of plants and animals.

point source The source of contaminant(s) discharged from 

any identifiable point, including wastewater discharges from 

ditches, channels, sewers, tunnels, and containers of various 

kinds (New Mexico State Office of Engineer, 2005).

precipitation Includes atmospheric hail, mist, rain, sleet 

and snow that descend upon the earth; the quantity of water 

accumulated from these events (New Mexico Office of State 

Engineer, 1999).

primary body contact recreation criteria Water-quality 

criteria set by the state to protect humans having direct body 

contact with the water where a possibility of ingestion exists, 

swimming being one example.

recharge Addition of water to an aquifer by infiltration, 

either directly into the aquifer or indirectly through 

another rock formation. Recharge may be natural, as when 

precipitation infiltrates to the water table, or artificial, as when 

water is injected through wells or spread over permeable 

surfaces for the purpose of recharging an aquifer (modified 

from New Mexico Office of State Engineer, 1999).

runoff That part of the precipitation that appears in surface 

streams (Langbein and Iseri, 1960).

sediment Fragmented rock and organic materials that are 

transported by, suspended in, or deposited by water or air. 

Sediments tend to accumulate in horizontal layers/beds in still 

or slow-flowing water.

streamflow Discharge in a natural channel of a surface 

stream course (New Mexico Office of State Engineer, 1999). 

total nitrogen The sum of concentrations of ammonium, 

nitrate, nitrite, and organic forms of nitrogen, expressed as the 

concentration of nitrogen, in a water sample.

total phosphorus The sum of concentrations of phosphorus 

in the forms of orthophosphate (PO4-3), polyphosphate 

(phosphate polymers linked by hydroxyl (OH-) groups and 

hydrogen atoms), organically bound phosphate (OP(OR)+3), 

and other forms of phosphorus, expressed as the concentration 

of phosphorus, in a water sample.

wastewater Water that contains dissolved or suspended 

solids as a result of human use (New Mexico Office of State 

Engineer, 1999).

wastewater treatment Processing of wastewater for the 

removal or reduction in the concentration of dissolved solids 

or other undesirable constituents (modified from New Mexico 

Office of State Engineer, 1999). 
Appendixes 1–9

Appendix 1. Summary statistics of selected surface-water-quality data collected by the U.S. Geological Survey in or near the Citizen Potawatomi TrOklahoma, 1985 through 2011.—Continued[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; L, liter; <, less than; >, greater than; --, not determined; e, natural exponent; ln, nathardness in mg/L; highest level of minimum reporting limits used for summary statistics, Adjusted maximum likelihood estimation used to estimate statistics for data sets with cContinuous Concentration (U.S. Environmental Protection Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”]

Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Date 

of first 

sample 

(month/ 

year)

Date 

of last 

sample 

(month/ 

year)

N

b

sa

North Canadian River near Harrah, Okla. (07241550)

Dissolved oxygen, in mg/L 2.50 8.10 9.70 11.4 21.0 -- -- 10/1985 9/2011 

pH (field), in standard units 6.70 7.80 8.10 8.30 9.20 -- -- 10/1985 9/2011 Specific conductance, in μS/

cm at 25 degrees Celsius

277 950 1,160 1,340 1,780 -- -- 10/1985 9/2011 

Water temperature, in 

degrees Celsius

0.0 10.4 18.0 25.1 34.3 -- -- 10/1985 9/2011 

Turbidity, in nephelometric 

turbidity units

<0.50 10.0 27.0 55.5 410 -- -- 5/1987 9/2004 

Five-day biochemical 

oxygen demand, in mg/L at 20 degrees Celsius

<2.00 2.30 4.10 7.15 33.0 -- -- 10/1985 9/2011 

Chemical oxygen demand, 

in mg/L

<10 30.0 40.0 50.0 80.0 -- -- 10/1985 9/1987 

Dissolved solids dried at 

180 degrees Celsius, in mg/L

159 573 730 854 1,000 -- -- 10/1985 9/2011 

Hardness, in mg/L calcium 

carbonate

95.6 250 310 383 441 -- -- 10/1985 9/2011 

Suspended solids, in mg/L 1.00 27.0 63.0 138 1,830 -- -- 10/1985 9/2011 Dissolved calcium, in mg/L 28.0 61.2 77.0 94.0 110 -- -- 10/1985 9/2011 Dissolved magnesium, in 

mg/L

6.16 23.0 29.0 36.0 42.0 -- -- 10/1985 9/2011 

Dissolved potassium, in 

mg/L

1.00 6.35 7.40 8.6 14.0 -- -- 10/1985 9/2011 

Dissolved sodium, in mg/L 12.9 95.8 120 140 180 -- -- 10/1985 9/2011 Total acid neutralizing 

capacity, in mg/L as calcium carbonate

86.0 162 199 224 306 -- -- 10/1985 9/2011 

Appendix 1. Summary statistics of selected surface-water-quality data collected by the U.S. Geological Survey in or near the Citizen Potawatomi TrOklahoma, 1985 through 2011.[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; L, liter; <, less than; >, greater than; --, not determined; e, natural exponent; ln, nathardness in mg/L; highest level of minimum reporting limits used for summary statistics, Adjusted maximum likelihood estimation used to estimate statistics for data sets with cContinuous Concentration (U.S. Environmental Protection Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”]
Appendix 1. Summary statistics of selected surface-water-quality data collected by the U.S. Geological Survey in or near the Citizen Potawatomi TrOklahoma, 1985 through 2011.—Continued [mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; L, liter; <, less than; >, greater than; --, not determined; e, natural exponent; ln, nathardness in mg/L; highest level of minimum reporting limits used for summary statistics, Adjusted maximum likelihood estimation used to estimate statistics for data sets with cContinuous Concentration (U.S. Environmental Protection Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”] Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Date of first sample (month/ year) Date of last sample (month/ year) N

b

sa

North Canadian River near Harrah, Okla. (07241550)—Continued Alkalinity, filtered, in mg/L as calcium carbonate 72.0 148 183 212 300 -- -- 7/1991 9/2011 

Dissolved bicarbonate, in mg/L 88.0 173 217 254 453 -- -- 7/1991 9/2011 Bicarbonate, in mg/L 105 219 240 268 312 -- -- 10/1985 7/1988 Carbon dioxide, in mg/L 0.20 2.00 3.10 6.05 72.0 -- -- 10/1985 9/2011 Dissolved carbonate, in mg/L <1 <1 <1 3.00 37.0 -- -- 7/1991 9/2011 Total carbonate, in mg/L <1 <1 <1 2.00 22.0 -- -- 10/1985 7/1988 Dissolved chloride, in mg/L 13.4 120 160 198 280 230 6.25 10/1985 9/2011 Dissolved fluoride, in mg/L 0.26 0.58 0.70 0.80 1.21 -- -- 8/1988 9/2011 Dissolved silica, in mg/L 1.10 7.81 9.86 12.0 16.0 -- -- 1/1988 9/2011 Dissolved sulfate, in mg/L 20.0 102 157 210 270 -- -- 10/1985 9/2011 Dissolved ammonia plus organic nitrogen, in mg/L as nitrogen 0.20 0.60 0.79 1.10 4.90 -- -- 10/1985 9/2011 Total ammonia plus organic nitrogen, in mg/L as nitrogen 0.60 1.10 1.40 1.50 3.80 -- -- 10/1987 9/2011 Dissolved nitrate plus nitrite, in mg/L as nitrogen <0.10 1.20 2.18 3.80 14.0 -- -- 10/1985 9/2011 Total nitrate plus nitrite, in mg/L as nitrogen 0.60 0.90 1.15 2.20 4.10 -- -- 11/1987 7/1988 Dissolved nitrate, in mg/L as nitrogen 0.06 1.16 2.14 3.72 14.0 -- -- 10/1985 9/2011 Nitrate, in mg/L as nitrogen 0.56 0.90 1.15 2.20 4.10 -- -- 11/1987 7/1988 Dissolved nitrite, in mg/L as 

nitrogen

<0.010 0.028 0.043 0.085 2.25 -- -- 10/1985 9/2011 

Nitrite, in mg/L as nitrogen 0.02 0.05 0.10 0.15 0.36 -- -- 11/1987 7/1988 
Appendix 1. Summary statistics of selected surface-water-quality data collected by the U.S. Geological Survey in or near the Citizen Potawatomi TrOklahoma, 1985 through 2011.—Continued[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; L, liter; <, less than; >, greater than; --, not determined; e, natural exponent; ln, nathardness in mg/L; highest level of minimum reporting limits used for summary statistics, Adjusted maximum likelihood estimation used to estimate statistics for data sets with cContinuous Concentration (U.S. Environmental Protection Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”]

Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Date 

of first 

sample 

(month/ 

year)

Date 

of last 

sample 

(month/ 

year)

N

b

sa

North Canadian River near Harrah, Okla. (07241550)—Continued

Dissolved organic nitrogen, 

in mg/L

<1.40 <1.40 <1.40 <1.40 3.80 -- -- 10/1985 9/2011 

Total organic nitrogen, in 

mg/L

<2.10 <2.10 <2.10 <2.10 2.70 -- -- 2/2003 9/2011 

Dissolved phosphorus, in 

mg/L

0.003 0.31 0.56 1.10 3.60 -- -- 10/1985 9/2011 

Phosphorus, in mg/L 0.24 0.67 0.90 1.46 3.40 -- -- 11/1985 9/2011 Dissolved nitrogen, in mg/L <0.3 2.10 3.20 4.90 15.0 -- -- 10/1985 9/2011 Total nitrogen, in mg/L 1.70 3.22 4.30 6.20 11.0 -- -- 10/1987 9/2011 Fecal coliform bacteria 

count, in colonies per 100 milliliters

<200 <200 500 1,200 110,000 -- -- 10/1985 9/2011 

Fecal streptococcal bacteria, 

in colonies per 100 milliliters

<10 107 240 767 80,000 -- -- 10/1985 9/2011 

Chlorophyll a in 

phytoplankton uncorrected for pheophytin, in μg/L

<1 11.0 27.0 60.0 181 -- -- 10/1989 6/1996 

Dissolved barium, in μg/L 44.1 120 134 160 230 -- -- 12/1987 9/2011 Dissolved copper, in μg/L <10 <10 <10 <10 13.0 -- -- 11/1985 9/2011 Dissolved iron, in μg/L <10 <10 10.2 16.0 730 1,000 0.0 11/1985 9/2011 Dissolved lead, in μg/L <100 <100 <100 <100 <100 e{1.273[ln(hardness)]-4.705} (1.46203-[(ln 

hardness(1.45712)]

4.8 11/1985 9/2011 

Dissolved lithium, in μg/L 6.0 20.2 26.5 33.0 46.0 -- -- 12/1987 9/2011 Dissolved manganese, in 

μg/L

<4.00 <4.00 8.40 16.0 190 -- -- 11/1985 9/2011 

Dissolved mercury, in μg/L <0.2 <0.2 <0.2 0.026 1.70 0.77 1.5 11/1985 9/2011 
Appendix 1. Summary statistics of selected surface-water-quality data collected by the U.S. Geological Survey in or near the Citizen Potawatomi TrOklahoma, 1985 through 2011.—Continued [mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; L, liter; <, less than; >, greater than; --, not determined; e, natural exponent; ln, nathardness in mg/L; highest level of minimum reporting limits used for summary statistics, Adjusted maximum likelihood estimation used to estimate statistics for data sets with cContinuous Concentration (U.S. Environmental Protection Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”] Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Date of first sample (month/ year) Date of last sample (month/ year) N

b

sa

North Canadian River near Harrah, Okla. (07241550)—Continued Dissolved molybdenum, in μg/L <60 <60 <60 <60 <60 -- -- 12/1987 9/2011 

Dissolved nickel, in μg/L <53 <53 <53 <53 <53 e(0.8460*(1n(hardness))-0.0584) (0.997) 0.0 12/1987 9/2011 Dissolved strontium, in μg/L 202 686 847 972 1,200 -- -- 12/1987 9/2011 Dissolved vanadium, in μg/L <10.0 <10.0 <10.0 <10.0 14.0 -- -- 12/1987 9/2011 Dissolved zinc, in μg/L <3 5.09 8.7 14.7 47.0 e(0.8473*(1n(hardness))-0.884) (0.986) 8.0 11/1985 9/2011 Dissolved arsenic, in μg/L 1.40 3.00 3.50 4.25 28.0 150 0.0 10/1985 9/2011 Dissolved selenium, in μg/L <2.00 <2.00 <2.00 <2.00 4.00 5 0.0 2/1986 9/2011 Suspended sediment, in mg/L 53.0 71.0 100 187 573 -- -- 10/1985 3/1986 

Little River near Tecumseh, Okla. (07230500) pH (field), in standard units 6.90 7.82 8.20 8.30 8.60 -- -- 1/1986 8/1990 

Specific conductance, in μS/ cm at 25 degrees Celsius 153 432 835 1,000 7,610 -- -- 1/1986 8/1990 Water temperature, in degrees Celsius 3.5 10.2 15.2 24.0 34.0 -- -- 1/1986 6/1990 

Canadian River at Purcell, Okla. (07229200) pH (field), in standard units 7.40 8.10 8.20 8.48 9.10 -- -- 12/1985 6/1990 

Specific conductance, in μS/cm at 25 degrees Celsius 615 1190 1,520 1,795 3,080 -- -- 1/1986 8/1990 Water temperature, in degrees Celsius 4.5 12.8 25.2 30.5 33.5 -- -- 12/1985 8/1990 
Appendix 2. Summary statistics of selected surface-water-quality data collected by the Citizen Potawatomi Nation, Oklahoma, 2009 through 2011.—[mg/L, milligrams per liter; L, μS/cm, microsiemens per centimeter; liter; all constituents analyzed in unfiltered samples, data from samples collected in October and Novembernitrogen and total phosphorus not summarized in this table]

Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value

o

sa

(m

y

Station “North Deer Creek at FireLake Grand Casino”

Dissolved oxygen concentration, in mg/L 1.94 4.08 6.88 9.74 16.5 10pH (field), in standard units 6.52 7.66 7.89 8.01 9.34 10Specific conductance, in μS/cm at 25 degrees Celsius 451 603 688 713 763 9/2Water temperature, in degrees Celsius 4.1 6.1 13.7 20.7 29.6 10Turbidity, in nephelometric turbidity units 5.44 14.1 24 44 185 10Hardness, in mg/L as calcium carbonate 122 207 241 260 296 9/2Alkalinity, in mg/L as calcium carbonate 160 194 240 256 275 10

Station “North Canadian River at Giverny 14 SE”

Dissolved oxygen concentration, in mg/L 5.52 9.74 10.6 11.8 15.9 10pH (field), in standard units 7.21 7.74 7.94 8.34 8.64 10Specific conductance, in μS/cm at 25 degrees Celsius 273 949 1,050 1,170 1,370 9/2Water temperature, in degrees Celsius 4.9 8.0 14.3 19.4 30.9 10Turbidity, in nephelometric turbidity units 4.1 16.5 24.1 45.4 822 11/Hardness, in mg/L as calcium carbonate 110 255 266 288 370 9/2Alkalinity, in mg/L as calcium carbonate 113 159 183 205 256 9/2

Station “Un-named Tributary to Squirrel Creek (outfall of city of Tecumseh wastewater treatment plant)”

Dissolved oxygen concentration, in mg/L 5.21 7.96 9.18 10.6 14.8 10pH (field), in standard units 7.69 7.99 8.19 8.31 8.81 10Specific conductance, in μS/cm at 25 degrees Celsius 354 545 600 678 1,000 9/2Water temperature, in degrees Celsius 4.7 10.8 15.1 23.2 32.2 10Turbidity, in nephelometric turbidity units 3.9 5.45 8.17 14.8 194 12Hardness, in mg/L as calcium carbonate 123 159 177 185 223 9/2Alkalinity, in mg/L as calcium carbonate 122 145 175 205 246 9/2

Station “Squirrel Creek at Tribal Administration Building”

Dissolved oxygen concentration, in mg/L 0.68 5.96 8.22 9.92 12.8 10pH (field), in standard units 7.23 7.84 8.04 8.22 8.48 10Specific conductance, in μS/cm at 25 degrees Celsius 268 477 531 646 1,100 9/2

Appendix 2. Summary statistics of selected surface-water-quality data collected by the Citizen Potawatomi Nation, Oklahoma, 2009 through 2011.[mg/L, milligrams per liter; L, μS/cm, microsiemens per centimeter; liter; all constituents analyzed in unfiltered samples, data from samples collected in October and November, nitrogen and total phosphorus not summarized in this table]
Appendix 2. Summary statistics of selected surface-water-quality data collected by the Citizen Potawatomi Nation, Oklahoma, 2009 through 2011.—[mg/L, milligrams per liter; L, μS/cm, microsiemens per centimeter; liter; all constituents analyzed in unfiltered samples, data from samples collected in October and Novembernitrogen and total phosphorus not summarized in this table] Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value 

o

sa

(m

y

Station “Squirrel Creek at Tribal Administration Building”—Continued Water temperature, in degrees Celsius 2.1 6 11.8 17.1 28.1 10

Turbidity, in nephelometric turbidity units 2.68 5.31 8.18 26.2 158 10Hardness, in mg/L as calcium carbonate 103 176 202 224 342 9/2Alkalinity, in mg/L as calcium carbonate 108 180 222 249 402 9/2

Station “North Canadian River at Knight 21” Dissolved oxygen concentration, in mg/L 7.47 11 12 13.1 18.8 11/

pH (field), in standard units 7.49 8.15 8.33 8.71 9.45 11/Specific conductance, in μS/cm at 25 degrees Celsius 566 863 1,000 1,080 1,280 9/2Water temperature, in degrees Celsius 6.8 9.3 16.5 24.2 34.2 11/Turbidity, in nephelometric turbidity units 9.16 17.4 30 62.6 476 11/Hardness, in mg/L as calcium carbonate 186 234 276 295 364 9/2Alkalinity, in mg/L as calcium carbonate 151 170 297 222 258 9/2

Station “Squirrel Creek at Tribal Environmental Office” Dissolved oxygen concentration, in mg/L 0.56 1.92 6.48 9.38 12.6 10

pH (field), in standard units 6.89 7.75 7.86 8.04 8.93 10Specific conductance, in μS/cm at 25 degrees Celsius 180 400 499 556 747 9/2Water temperature, in degrees Celsius 2.4 5.5 11.8 17.8 27.5 10Turbidity, in nephelometric turbidity units 2.96 6.34 13.5 46.8 101 12Hardness, in mg/L as calcium carbonate 82.0 136 184 203 242 9/2Alkalinity, in mg/L as calcium carbonate 89.0 144 180 213 276 9/2

Station “North Canadian River at Knight 29” Dissolved oxygen concentration, in mg/L 7.2 11.1 12.4 13.6 20.0 4/2

pH (field), in standard units 7.0 8.0 8.4 8.8 9.2 4/2Specific conductance, in μS/cm at 25 degrees Celsius 574 875 1,010 1,090 1,280 9/2Water temperature, in degrees Celsius 6.6 12.2 19.1 25.7 26.0 4/2Turbidity, in nephelometric turbidity units 8.7 19.5 28.5 62.6 555 4/2Hardness, in mg/L as calcium carbonate 179 230 285 293 353 9/2Alkalinity, in mg/L as calcium carbonate 150 177 197 217 249 9/2
Appendix 2. Summary statistics of selected surface-water-quality data collected by the Citizen Potawatomi Nation, Oklahoma, 2009 through 2011.—[mg/L, milligrams per liter; L, μS/cm, microsiemens per centimeter; liter; all constituents analyzed in unfiltered samples, data from samples collected in October and Novembernitrogen and total phosphorus not summarized in this table]

Constituent name Minimum value 25th per- centile 50th per- centile 75th per- centile Maximum value

o

sa

(m

y

Station “North Canadian River at Luther Road (USGS streamflow-gaging station 07241550)”

Dissolved oxygen concentration, in mg/L 5.5 8.7 10.1 11.2 15.9 4/2pH (field), in standard units 6.8 7.3 7.5 7.8 8.9 4/2Specific conductance, in μS/cm at 25 degrees Celsius 250 922 1,040 1,100 1,400 9/2Water temperature, in degrees Celsius 6.2 9.2 17.0 23.3 32.0 4/2Turbidity, in nephelometric turbidity units 5.9 13.7 24.1 37.3 1,000 4/2Hardness, in mg/L as calcium carbonate 130 238 262 278 367 9/2Alkalinity, in mg/L as calcium carbonate 124 151 182 206 241 9/2

Station “Little River at U.S. Highway 177”

Dissolved oxygen concentration, in mg/L 7 9 11 12 14 4/2pH (field), in standard units 7 8 8 8 9 4/2Specific conductance, in μS/cm at 25 degrees Celsius 712 917 1,000 1,350 2,200 9/2Water temperature, in degrees Celsius 7 10 21 25 37 4/2Turbidity, in nephelometric turbidity units 3 5 7 21 76 4/2Hardness, in mg/L as calcium carbonate 208 258 302 313 332 9/2Alkalinity, in mg/L as calcium carbonate 175 249 282 293 304 9/2
Appendix 3. Summary statistics of surface-water-quality data collected by the Oklahoma Department of Environmental Quality in or near the Citizen Jurisdictional Area, Oklahoma, 2003.[Adjusted maximum likelihood estimation used to estimate statistics for data sets with censored values; Primary contact standards from State of Oklahoma (2007), note that thosthe geometric mean of at least five samples collected within 30-day periods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 10analyzed in unfiltered samples, Oklahoma primary-contact standards from State of Oklahoma (2007]

Constituent name Minmum value 25th percentile 50th percentile 75th percentile Maximum value

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

Number 

of 

samples

Station NC08

Fecal coliform bacteria <10 105 200 450 1,100 200 40.0 5/2003 9/2003 20 Escherichia coli. bacteria <10 17 74 140 400 126 30.0 5/2003 9/2003 20 Enterococcus bacteria 41.00 100 265 405 1,500 33 100 5/2003 9/2003 20 

Station CW01

Fecal coliform bacteria <10 60 200 800 9,000 200 47.4 5/2003 9/2003 19 Escherichia coli. bacteria <10 30 63 223 689 126 42.1 5/2003 9/2003 19 Enterococcus bacteria 90 200 300 700 4,000 33 100 5/2003 9/2003 19 

Station NC07

Fecal coliform bacteria 90 345 685 2,250 14,000 200 80.0 5/2003 9/2003 20 Escherichia coli. bacteria <10 31 201 268 3,076 126 55.0 5/2003 9/2003 20 Enterococcus bacteria <10 300 850 2,200 16,000 33 95.0 5/2003 9/2003 20 

Station NC06

Fecal coliform bacteria <10 120 355 1,500 6,000 200 55.0 5/2003 9/2003 20 Escherichia coli. bacteria <10 15 41 127 1,935 126 25.0 5/2003 9/2003 20 Enterococcus bacteria 60 350 2,900 41,500 312,000 33 100 5/2003 9/2003 20 

Station OC01

Fecal coliform bacteria <10 16 150 400 2,100 200 31.6 6/2003 9/2003 19 Escherichia coli. bacteria <10 52 96 216 4,611 126 26.3 6/2003 9/2003 19 Enterococcus bacteria <10 7 40 60 400 33 52.6 6/2003 9/2003 19 
Appendix 4. Summary statistics of surface-water-quality data collected by the Kickapoo Tribe of Oklahoma in or near the Citizen Potawatomi Nation Oklahoma, 2009 through 2011.—Continued [mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; L, liter; all constituents analyzed in unfiltered samples] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value Date of first sample (month/year) 

Station “NCR2”

Dissolved oxygen concentration, in mg/L 7.47 9.10 10.0 11.4 16.5 7/2009 pH (field), in standard units 7.60 7.94 8.09 8.24 8.57 7/2009 Specific conductance, in μS/cm at 25 degrees Celsius 395 920 1,040 1,160 1,390 7/2009 Water temperature, in degrees Celsius 9.0 13.0 21.7 25.6 30.4 7/2009 Turbidity, in nephelometric turbidity units 7.40 13.2 33 63.4 259 8/2009 Dissolved solids, in mg/L 253 592 652 738 888 7/2009 Ammonia, in mg/L as nitrogen <0.1 <0.1 <0.1 <0.1 0.75 10/2010 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.1 <0.1 <0.1 1 2.63 10/2010 Nitrite plus nitrate as nitrogen, in mg/L 1.04 3.52 5 6 8.38 7/2009 Phosphorus, in mg/L 0.38 0.56 1.00 2 3.15 7/2009 Escherichia coli. bacteria, in colonies per 100 milliliters <1 51 248 579 2,420 7/2009 

Station “NCR1”

Dissolved oxygen concentration, in mg/L 7.45 8.20 9.14 11.2 20.3 7/2009 pH (field), in standard units 7.51 7.74 7.88 8.16 8.40 7/2009 Specific conductance, in μS/cm at 25 degrees Celsius 425 933 1,020 1,140 1,270 7/2009 Water temperature, in degrees Celsius 10.1 17.8 22.4 26.4 28.2 7/2009 Turbidity, in nephelometric turbidity units 5.80 9.51 20.0 66.4 241 8/2009 Dissolved solids, in mg/L 272 597 654 718 768 7/2009 Ammonia, in mg/L as nitrogen <0.1 <0.1 <0.1 <0.1 0.95 10/2010 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.1 <0.1 <0.1 0.95 2.89 10/2010 Nitrite plus nitrate as nitrogen, in mg/L 1.21 3.44 5.00 6.40 8.78 7/2009 Phosphorus, in mg/L 0.40 0.69 1.22 1.55 3.15 7/2009 Escherichia coli. bacteria, in colonies per 100 milliliters <1 42 128 248 1,990 7/2009 

Station “NCR4”

Dissolved oxygen concentration, in mg/L 7.40 9.62 11.0 12.7 18.4 7/2009 Specific conductance, in μS/cm at 25 degrees Celsius 322 904 1,020 1,110 1,370 7/2009 Water temperature, in degrees Celsius 3.2 12.4 20.1 28.2 31 7/2009 Turbidity, in nephelometric turbidity units 19.4 25.5 58.4 120 901 8/2009 Dissolved solids, in mg/L 206 579 644 696 878 7/2009 

Appendix 4. Summary statistics of surface-water-quality data collected by the Kickapoo Tribe of Oklahoma in or near the Citizen Potawatomi Nation Oklahoma, 2009 through 2011.[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; L, liter; all constituents analyzed in unfiltered samples]
Appendix 4. Summary statistics of surface-water-quality data collected by the Kickapoo Tribe of Oklahoma in or near the Citizen Potawatomi Nation Oklahoma, 2009 through 2011.—Continued [mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; L, liter; all constituents analyzed in unfiltered samples] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value Date of first sample (month/year) 

Station “NCR4”—Continued Ammonia, in mg/L as nitrogen <0.1 <0.1 <0.1 <0.1 1 10/2010 

Ammonia plus organic nitrogen, in mg/L as nitrogen <0.1 <0.1 <0.1 2.42 3.05 10/2010 Nitrite plus nitrate as nitrogen, in mg/L 0.76 2.32 3.66 4.67 6.15 7/2009 Phosphorus, in mg/L 0.35 0.62 0.90 1.17 1.86 7/2009 Escherichia coli. bacteria, in colonies per 100 milliliters <1 21 115 260 921 7/2009 

Station “NCR5” Dissolved oxygen concentration, in mg/L 7.05 9.80 10.8 12.2 18.3 7/2009 

Specific conductance, in μS/cm at 25 degrees Celsius 305 888 1,010 1,140 1,340 7/2009 Water temperature, in degrees Celsius 4.2 10.6 19.3 25.7 32.1 7/2009 Turbidity, in nephelometric turbidity units 17.8 28.8 50.8 106 621 9/2009 Dissolved solids, in mg/L 81.2 542 632 702 785 9/2009 Ammonia, in mg/L as nitrogen <0.1 <0.1 <0.1 <0.1 <0.1 10/2010 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.1 <0.1 <0.1 2.54 4.03 10/2010 Nitrite plus nitrate as nitrogen, in mg/L 0.60 2.57 3.28 4.28 5.90 7/2009 Phosphorus, in mg/L 0.36 0.70 0.98 1.16 1.74 7/2009 Escherichia coli. bacteria, in colonies per 100 milliliters <1 13 45 131 579 7/2009 

Station “NCR7” Dissolved oxygen concentration, in mg/L 6.93 9.17 11.0 12.5 18.0 11/2009 

Specific conductance, in μS/cm at 25 degrees Celsius 274 826 1,040 1,110 1,260 11/2009 Water temperature, in degrees Celsius 5.3 9.3 15.4 25.4 32.5 11/2009 Turbidity, in nephelometric turbidity units 21.9 29.8 43.0 146 990 11/2009 Dissolved solids, in mg/L 176 526 645 708 810 11/2009 Ammonia, in mg/L as nitrogen <0.1 <0.1 <0.1 <0.1 <0.1 10/2010 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.1 <0.1 <0.1 2.58 2.77 10/2010 Nitrite plus nitrate as nitrogen, in mg/L <0.2 1.61 2.74 3.78 7.44 11/2009 Phosphorus, in mg/L 0.33 0.51 0.68 0.91 1.40 11/2009 Escherichia coli. bacteria, in colonies per 100 milliliters <1 7 25 117 613 11/2009 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless noprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

sa

Station 520510000110-01

Dissolved oxygen, 

in mg/L

5.22 7.81 9.36 11.4 20.3 NA NA NA NA 2/1999 9/2005 

pH, in standard 

units

6.82 7.82 8.10 8.46 9.60 NA NA NA NA 2/1999 9/2005 

Specific 

conductance, in μS/cm at 25 degrees Celsius

153 761 997 1,190 1,390 NA NA NA NA 11/1998 9/2005 

Water 

temperature, in degrees Celsius

1.3 12.9 19.7 28.0 34.3 NA NA NA NA 11/1998 9/2005 

Turbidity, in 

nephelometric turbidity units

6.0 21.2 46.0 89.0 1,000 NA NA NA NA 11/1998 9/2005 

Dissolved solids, 

in mg/L

98.0 472 583 680 892 NA NA NA NA 11/1998 9/2005 

Suspended solids, 

in mg/L

5.0 60.5 121 317 1,520 NA NA NA NA 11/1998 12/2000 

Hardness, in mg/L 

as calcium carbonate

1.92 221 275 343 3,950 NA NA NA NA 2/1999 9/2005 

Alkalinity, 

in mg/L as calcium carbonate

82.0 134 164 196 262 NA NA NA NA 11/1998 9/2005 

Chloride, in mg/L 21.5 106 140 162 290 230 1.61 NA NA 11/1998 9/2005 

Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

b

sa

Station 520510000110-01—Continued Sulfate, in mg/L 119 276 397 519 3,890 NA NA NA NA 11/1998 9/2005 

Ammonia, in mg/L as nitrogen <0.05 <0.05 0.10 0.18 1.71 NA NA NA NA 2/1999 9/2005 Ammonia plus organic nitrogen, in mg/L 0.50 1.19 1.43 1.82 3.10 NA NA NA NA 2/1999 9/2005 Nitrite, in mg/L as nitrogen <0.05 0.06 0.09 0.12 0.45 NA NA NA NA 11/1998 2/2005 Nitrate, in mg/L as nitrogen <0.05 0.80 1.67 3.03 6.66 NA NA NA NA 11/1998 2/2005 Phosphate, in mg/L as phosphorus 0.063 0.305 0.447 0.834 1.90 NA NA NA NA 11/1998 9/2005 Phosphorus, in mg/L 0.28 0.52 0.80 1.18 2.12 NA NA NA NA 11/1998 9/2005 Arsenic, in μg/L <10 <10 <10 <10 26 150 0.0 NA NA 5/1999 9/2004 Chromium, in μg/L <5 <5 <5 <5 124 11 13.3 NA NA 5/1999 9/2004 Copper, in μg/L <5 <5 <5 <10 54 9 7.14 NA NA 5/1999 9/2004 Lead, in μg/L <10 <10 <10 <10 80 e{1.273 [ln(hardness)]-4.705} (1.46203- [(ln hardness (1.45712)] 7.14 NA NA 5/1999 9/2004 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

b

sa

Station 520510000110-01—Continued

Mercury, in μg/L <0.5 <0.5 <0.5 <0.5 1 77 0.0 NA NA 5/1999 9/2004 Nickel, in μg/L <25 <25 <25 <25 73 e(0.8460*

(1n(hardness))-0.0584)

(0.997)

20.0 NA NA 5/1999 9/2004 

Selenium, in μg/L <5 <5 <5 <5 <5 5 0.0 NA NA 5/1999 9/2004 Silver, in μg/L <10 <10 <10 <10 <10 3.2 0.0 NA NA 5/1999 9/2004 Thallium, in μg/L <10 <10 <10 <10 <10 NA NA NA NA 5/1999 9/2004 Zinc, in μg/L <5 14 21 37 212 e(0.8473*

(1n(hardness))-0.884)

(0.986)

7.14 NA NA 5/1999 2/2005 

Fecal coliform 

bacteria

<10 100 200 600 5,000 NA NA 200 47.6 6/2001 6/2004 

Escherichia coli. 

bacteria

<10 <10 36 200 355 NA NA 126 30.0 6/2001 6/2004 

Enterococcus 

bacteria

40 100 300 850 12,000 NA NA 33 100 6/2001 6/2004 

Station 520510000110-02

Dissolved oxygen, 

in mg/L

5.99 9.50 11.8 12.2 16.0 NA NA NA NA 10/2000 2/2002 

pH, in standard 

units

7.82 7.96 8.16 8.46 8.83 NA NA NA NA 10/2000 2/2002 

Specific 

conductance, in μS/cm at 25 degrees Celsius

199 829 1,010 1,110 1,280 NA NA NA NA 10/2000 2/2002 

Water 

temperature, in degrees Celsius

3.5 9.9 19.0 27.1 34.0 NA NA NA NA 10/2000 2/2002 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

b

sa

Station 520510000110-02—Continued Turbidity, in nephelometric turbidity units 38.0 110 162 342 1,000 NA NA NA NA 10/2000 2/2002 

Dissolved solids, in mg/L 127 532 648 715 816 NA NA NA NA 10/2000 2/2002 Suspended solids, in mg/L 10 372 735 1,100 1,460 NA NA NA NA 10/2000 12/2000 Hardness, in mg/L as calcium carbonate 92.0 204 303 336 3,320 NA NA NA NA 10/2000 2/2002 Alkalinity, in mg/L as calcium carbonate 80.0 163 188 220 260 NA NA NA NA 10/2000 2/2002 Chloride, in mg/L 21.6 103 126 146 158 230 0.0 NA NA 10/2000 2/2002 Sulfate, in mg/L 213 303 406 471 518 NA NA NA NA 10/2000 2/2002 Ammonia, in mg/L as nitrogen <0.05 <0.05 0.10 0.19 0.27 NA NA NA NA 10/2000 2/2002 Ammonia plus organic nitrogen, in mg/L 1.03 1.14 1.42 1.87 2.70 NA NA NA NA 10/2000 2/2002 Nitrite, in mg/L as nitrogen <0.05 0.06 0.08 0.14 0.27 NA NA NA NA 10/2000 2/2002 Nitrate, in mg/L 

as nitrogen

<0.05 0.64 0.65 1.23 1.76 NA NA NA NA 10/2000 2/2002 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

b

sa

Station 520510000110-02—Continued

Phosphate, 

in mg/L as phosphorus

0.100 0.210 0.270 0.396 0.501 NA NA NA NA 10/2000 2/2002 

Phosphorus, in 

mg/L

0.426 0.452 0.472 0.580 1.30 NA NA NA NA 10/2000 2/2002 

Arsenic, in μg/L <10 <10 <10 13 22 150 0.0 NA NA 10/2000 8/2001 Chromium, in 

μg/L

<5 7.0 10 12 102 11 40.0 NA NA 10/2000 8/2001 

Copper, in μg/L <5 6.0 8.0 13 46 9 40.0 NA NA 10/2000 8/2001 Lead, in μg/L 10 10 10 15 43 e{1.273

[ln(hardness)]-4.705}

(1.46203-

[(ln hardness

(1.45712)]

80.0 NA NA 10/2000 8/2001 

Mercury, in μg/L <0.05 <0.05 <0.05 <0.05 1.0 77 0.0 NA NA 10/2000 8/2001 Nickel, in μg/L 10 10 13 15 66 e(0.8460*

(1n(hardness))-0.0584)

(0.997)

20.0 NA NA 10/2000 8/2001 

Selenium, in μg/L <10 <10 <10 <10 <10 5 0.0 NA NA 10/2000 8/2001 Silver, in μg/L <5 <5 <5 <5 <5 3.2 0.0 NA NA 10/2000 8/2001 Thallium, in μg/L <10 <10 <10 <10 <10 NA NA NA NA 10/2000 8/2001 Zinc, in μg/L 10 21 34 47 156 e(0.8473*

(1n(hardness))-0.884)

(0.986)

40.0 NA NA 10/2000 8/2001 

Fecal coliform 

bacteria

<10 58 200 300 300 200 47.4 6/2001 2/2002 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

b

sa

Station 520510000110-02—Continued Escherichia coli. bacteria <10 <10 <10 <10 183 126 42.1 6/2001 8/2001 

Enterococcus bacteria 100 100 100 1,050 2,000 33 100 6/2001 8/2001 

Station 520510000110-03 Dissolved oxygen, in mg/L 6.91 8.35 8.90 10.1 12.3 NA NA NA NA 3/2002 9/2003 

pH, in standard units 6.63 7.67 7.89 8.58 9.16 NA NA NA NA 3/2002 1/2003 Specific conductance, in μS/cm at 25 degrees Celsius 435 658 744 928 986 NA NA NA NA 3/2002 1/2003 Water temperature, in degrees Celsius 5.0 12.6 14.1 21.6 26 NA NA NA NA 3/2002 1/2003 Turbidity, in nephelometric turbidity units 33.0 54.0 58.0 87.0 1,000 NA NA NA NA 3/2002 1/2003 Dissolved solids, in mg/L 278 439 518 594 639 NA NA NA NA 3/2002 9/2003 Hardness, in mg/L as calcium carbonate 154 166 204 258 325 NA NA NA NA 3/2002 9/2003 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

b

sa

Station 520510000110-03—Continued

Alkalinity, 

in mg/L as calcium carbonate

103 110 132 147 154 NA NA NA NA 3/2002 9/2003 

Ammonia, 

in mg/L as nitrogen

<0.05 <0.05 <0.05 0.49 0.55 NA NA NA NA 3/2002 9/2003 

Ammonia 

plus organic nitrogen, in mg/L

0.42 0.95 2.26 2.94 3.73 NA NA NA NA 3/2002 9/2003 

Nitrite, in mg/L as 

nitrogen

<0.05 <0.05 0.08 0.08 0.32 NA NA NA NA 3/2002 9/2003 

Nitrate, in mg/L 

as nitrogen

<0.05 0.59 0.92 1.72 2.63 NA NA NA NA 3/2002 9/2003 

Phosphate, 

in mg/L as phosphorus

0.029 0.302 0.507 0.934 0.975 NA NA NA NA 3/2002 9/2003 

Phosphorus, in 

mg/L

0.437 0.692 0.910 1.18 1.47 NA NA NA NA 3/2002 9/2003 

Fecal coliform 

bacteria

30 75 200 350 1,000 NA NA 200 42.9 8/2002 9/2003 

Escherichia coli.

bacteria

<10 <10 20 85 98 NA NA 126 0 8/2002 9/2003 

Enterococcus 

bacteria

100 150 200 250 1,400 NA NA 33 100 8/2002 9/2003 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to ewith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 samperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless noprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

sa

Station 520510000110-04 Dissolved oxygen, in mg/L 5.82 7.98 9.05 10.7 11.7 NA NA NA NA 3/2002 9/2003 

pH, in standard units 6.80 7.65 8.16 8.47 9.10 NA NA NA NA 3/2002 9/2003 Specific conductance, in μS/cm at 25 degrees Celsius 350 600 780 939 983 NA NA NA NA 3/2002 9/2003 Water temperature, in degrees Celsius 5.0 12.6 17.2 24.3 27.3 NA NA NA NA 3/2002 9/2003 Turbidity, in nephelometric turbidity units 23.0 41.8 48.0 85.0 1,000 NA NA NA NA 3/2002 9/2003 Dissolved solids, in mg/L 224 384 506 593 621 NA NA NA NA 3/2002 9/2003 Hardness, in mg/L as calcium carbonate 140 153 167 214 300 NA NA NA NA 3/2002 9/2003 Alkalinity, in mg/L as calcium carbonate 104 116 130 152 149 NA NA NA NA 3/2002 9/2003 Ammonia, in mg/L as 

nitrogen

<0.05 <0.05 0.20 0.38 0.40 NA NA NA NA 3/2002 9/2003 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to ewith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 samperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless noprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

sa

Station 520510000110-04—Continued

Ammonia 

plus organic nitrogen, in mg/L

0.42 1.04 2.22 3.31 3.66 NA NA NA NA 3/2002 9/2003 

Nitrite, in mg/L as 

nitrogen

<0.05 0.06 0.08 0.26 0.28 NA NA NA NA 3/2002 9/2003 

Nitrate, in mg/L 

as nitrogen

0.29 0.68 1.32 2.18 2.62 NA NA NA NA 3/2002 9/2003 

Phosphate, 

in mg/L as phosphorus

0.065 0.416 0.774 0.939 1.27 NA NA NA NA 3/2002 9/2003 

Phosphorus, in 

mg/L

0.458 0.859 0.962 1.26 1.37 NA NA NA NA 3/2002 9/2003 

Mercury, in μg/L <0.5 <0.5 <0.5 <0.5 <0.5 NA NA NA NA 4/2002 4/2002 Fecal coliform 

bacteria

<10 90 300 400 500 NA NA 200 57.1 8/2002 9/2003 

Escherichia coli.

bacteria

<10 20 41 146 148 NA NA 126 28.6 8/2002 9/2003 

Enterococcus 

bacteria

70 105 170 3,100 8,000 NA NA 33 100 8/2002 9/2003 

Station 520510000110-05

Dissolved oxygen, 

in mg/L

2.64 7.68 9.67 12.4 25.0 NA NA NA NA 1/2002 9/2005 

pH, in standard 

units

5.87 7.88 8.10 8.50 9.98 NA NA NA NA 1/2002 9/2005 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

b

sa

Station 520510000110-05—Continued Specific conductance, in μS/cm at 25 degrees Celsius 314 667 809 968 1,309 NA NA NA NA 1/2002 9/2005 

Water temperature, in degrees Celsius 0.0 10.6 17.0 25.6 34.4 NA NA NA NA 1/2002 9/2005 Turbidity, in nephelometric turbidity units 15.0 32.3 54.0 116 1,000 NA NA NA NA 1/2002 9/2005 Dissolved solids, in mg/L 201 427 527 616 888 NA NA NA NA 1/2002 9/2005 Hardness, in mg/L as calcium carbonate 146 216 260 308 449 NA NA NA NA 1/2002 9/2005 Alkalinity, in mg/L as calcium carbonate 109 138 157 187 244 NA NA NA NA 1/2002 9/2005 Chloride, in mg/L 22.6 98.7 123 135 171 NA NA NA NA 2/2002 9/2005 Sulfate, in mg/L 166 232 341 482 4,610 NA NA NA NA 2/2002 9/2005 Ammonia, in mg/L as nitrogen <0.05 <0.05 0.09 0.20 0.81 NA NA NA NA 1/2002 9/2005 Ammonia 

plus organic nitrogen, in mg/L

0.59 1.39 1.82 2.50 4.86 NA NA NA NA 1/2002 9/2005 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

b

sa

Station 520510000110-05—Continued

Nitrite, in mg/L as 

nitrogen

<0.05 <0.05 0.07 0.11 0.22 NA NA NA NA 1/2002 2/2005 

Nitrate, in mg/L 

as nitrogen

0.28 0.75 1.67 3.29 6.25 NA NA NA NA 1/2002 2/2005 

Phosphate, 

in mg/L as phosphorus

0.103 0.245 0.360 0.602 1.36 NA NA NA NA 1/2002 9/2005 

Phosphorus, in 

mg/L

0.362 0.538 0.725 0.868 1.70 NA NA NA NA 1/2002 9/2005 

Arsenic, in μg/L <10 <10 <10 <10 <10 150 0.0 NA NA 4/2002 9/2004 Chromium, in 

μg/L

<5 <5 <5 13 24 11 50.0 NA NA 4/2002 9/2004 

Copper, in μg/L <5 <5 <5 14 18 9 50.0 NA NA 4/2002 9/2004 Lead, in μg/L <5 <5 <5 13 28 e{1.273

[ln(hardness)]-4.705}

(1.46203-

[(ln hardness

(1.45712)]

25.0 NA NA 4/2002 9/2004 

Mercury, in μg/L <0.5 <0.5 <0.5 <0.5 <0.5 77 0.0 NA NA 4/2002 9/2004 Nickel, in μg/L 7 7 10 15 21 e(0.8460*

(1n(hardness))-0.0584)

(0.997)

0.0 NA NA 4/2002 9/2004 

Selenium, in μg/L <5 <5 <5 <5 <5 5 0.0 NA NA 4/2002 9/2004 Silver, in μg/L <2 <2 <2 <2 <2 3.2 0.0 NA NA 4/2002 9/2004 Thallium, in μg/L <5 <5 <5 6 9 NA 0.0 NA NA 4/2002 9/2004 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

b

sa

Station 520510000110-05—Continued Zinc, in μg/L 10 14 30 52 70 e(0.8473* (1n(hardness))-0.884) (0.986) 25.0 NA NA 4/2002 9/2004 

Fecal coliform bacteria 20 110 370 700 6,000 NA NA 200 53.8 1/2002 6/2004 Escherichia coli. bacteria <10 20 52 175 298 NA NA 126 27.3 8/2002 6/2004 Enterococcus bacteria <10 20 200 900 5,000 NA NA 33 72.7 8/2002 6/2004 

Station 520510000110-06 Dissolved oxygen, in mg/L 6.36 6.86 8.65 9.41 11.2 NA NA NA NA 3/2002 9/2003 

pH, in standard units 6.71 7.61 7.86 8.79 9.15 NA NA NA NA 3/2002 9/2003 Specific conductance, in μS/cm at 25 degrees Celsius 477 722 847 900 1,010 NA NA NA NA 3/2002 9/2003 Water temperature, in degrees Celsius 5.1 12.0 16.5 22.2 25.0 NA NA NA NA 3/2002 9/2003 Turbidity, in nephelometric turbidity units 38.0 55.0 83.0 100 1,000 NA NA NA NA 3/2002 9/2003 Dissolved solids, 

in mg/L

305 462 543 598 647 NA NA NA NA 3/2002 9/2003 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

b

sa

Station 520510000110-06—Continued

Hardness, in mg/L 

as calcium carbonate

166 204 211 248 316 NA NA NA NA 3/2002 9/2003 

Alkalinity, in 

mg/L as calcium carbonate

104 115 133 146 240 NA NA NA NA 3/2002 9/2003 

Ammonia, 

in mg/L as nitrogen

<0.05 <0.05 <0.05 0.15 0.45 NA NA NA NA 3/2002 9/2003 

Ammonia 

plus organic nitrogen, in mg/L

0.43 0.89 1.15 2.70 4 NA NA NA NA 3/2002 9/2003 

Nitrite, in mg/L as 

nitrogen

<0.05 <0.05 <0.05 0.10 0.37 NA NA NA NA 3/2002 9/2003 

Nitrate, in mg/L as 

nitrogen

<0.05 0.36 0.93 1.57 3 NA NA NA NA 3/2002 9/2003 

Phosphate, 

in mg/L as phosphorus

0.025 0.213 0.378 0.547 0.931 NA NA NA NA 3/2002 9/2003 

Phosphorus, in 

mg/L

0.359 0.401 0.710 0.930 1.55 NA NA NA NA 3/2002 9/2003 

Fecal coliform 

bacteria

40 72 115 200 300 NA NA 200 12.5 8/2002 9/2003 

Escherichia coli.

bacteria

<10 <10 <10 20 63 NA NA 126 0 8/2002 9/2003 

Enterococcus 

bacteria

70 175 250 725 1,000 NA NA 33 100 8/2002 9/2003 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to ewith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 samperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless noprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

sa

Station 52050000110-07 Dissolved oxygen, in mg/L 5.84 7.61 8.76 9.52 13.9 NA NA NA NA 3/2002 9/2003 

pH, in standard units 6.69 7.65 7.77 8.24 8.97 NA NA NA NA 3/2002 9/2003 Specific conductance, in μS/cm at 25 degrees Celsius 477 722 847 900 1,010 NA NA NA NA 3/2002 9/2003 Water temperature, in degrees Celsius 5.1 12.0 16.5 22.2 25.0 NA NA NA NA 3/2002 9/2003 Turbidity, in nephelometric turbidity units 38.0 55.0 83.0 100 1,000 NA NA NA NA 3/2002 9/2003 Dissolved solids, in mg/L 305 462 543 598 647 NA NA NA NA 3/2002 9/2003 Hardness, in mg/L as calcium carbonate 166 204 211 248 316 NA NA NA NA 3/2002 9/2003 Alkalinity, in mg/L as calcium carbonate 104 115 133 146 240 NA NA NA NA 3/2002 9/2003 Ammonia, in mg/L as 

nitrogen

<0.05 <0.05 <0.05 0.15 0 NA NA NA NA 3/2002 9/2003 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to ewith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 samperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless noprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

sa

Station 52050000110-07—Continued

Ammonia 

plus organic nitrogen, in mg/L

0.43 0.89 1.15 2.70 3.97 NA NA NA NA 3/2002 9/2003 

Nitrite, in mg/L as 

nitrogen

<0.05 <0.05 <0.05 0.10 0.37 NA NA NA NA 3/2002 9/2003 

Nitrate, in mg/L 

as nitrogen

<0.05 0.36 0.93 1.57 2.72 NA NA NA NA 3/2002 9/2003 

Phosphate, 

in mg/L as phosphorus

0.025 0.213 0.378 0.547 0.93 NA NA NA NA 3/2002 9/2003 

Phosphorus, in 

mg/L

0.359 0.401 0.710 0.930 1.55 NA NA NA NA 3/2002 9/2003 

Fecal coliform 

bacteria

40 72 115 200 300 NA NA 200 12.5 8/2002 9/2003 

Escherichia coli.

bacteria

<10 <10 <10 20 63 NA NA 126 0 8/2002 9/2003 

Enterococcus 

bacteria

70 175 250 725 1,000 NA NA 33 100 8/2002 9/2003 

Station 520510000110-1S

Dissolved oxygen, 

in mg/L

4.28 5.54 6.81 6.87 6.93 NA NA NA NA 7/2001 2/2002 

pH, in standard 

units

8.68 8.71 8.74 8.76 8.79 NA NA NA NA 7/2001 8/2001 

Specific 

conductance, in μS/cm at 25 degrees Celsius

785 885 985 989 993 NA NA NA NA 7/2001 2/2002 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) 

b

sa

Station 520510000110-1S—Continued Water temperature, in degrees Celsius 3.30 17.2 31.2 31.5 31.8 NA NA NA NA 7/2001 2/2002 

Turbidity, in nephelometric turbidity units 23 35.8 51.5 80.0 131 NA NA NA NA 7/2001 2/2002 Dissolved solids, in mg/L 503 566 630 635 641 NA NA NA NA 7/2001 2/2002 Hardness, in mg/L as calcium carbonate 211 219 227 298 370 NA NA NA NA 7/2001 2/2002 Alkalinity, in mg/L as calcium carbonate 111 152 193 196 200 NA NA NA NA 7/2001 9/2001 Ammonia, in mg/L as nitrogen <0.05 <0.05 <0.05 <0.05 0.38 NA NA NA NA 7/2001 2/2002 Ammonia plus organic nitrogen, in mg/L 0.47 1.12 1.76 2.26 2.53 NA NA NA NA 7/2001 2/2002 Nitrite, in mg/L as nitrogen <0.05 <0.05 0.06 0.09 0.12 NA NA NA NA 7/2001 2/2002 Nitrate, in mg/L as nitrogen <0.05 <0.05 <0.05 <0.05 1.15 NA NA NA NA 7/2001 2/2002 Phosphate, 

in mg/L as phosphorus

0.068 0.090 0.127 0.224 0.427 NA NA NA NA 7/2001 2/2002 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued[mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC

Percent of 

samples 

in which 

measurement 

exceeded 

CCC

Primary 

Body 

Contact 

Recreation 

Standard

Percent of 

samples 

exceeding 

Primary 

Body 

Contact 

Recreation 

Standard

Date 

of first 

sample 

(month/

year)

Date 

of last 

sample 

(month/

year)

b

sa

Station 520510000110-1S—Continued

Phosphorus, in 

mg/L

0.101 0.298 0.450 0.548 0.58 NA NA NA NA 7/2001 2/2002 

Fecal coliform 

bacteria

<10 58 150 400 600 NA NA 200 25.0 7/2001 2/2002 

Escherichia coli.

bacteria

<10 <10 <10 <10 <10 NA NA 126 0 7/2001 9/2001 

Enterococcus 

bacteria

<10 <10 110 135 160 NA NA 33 66.6 7/2001 9/2001 

Station 520800030070-01

Dissolved solids, 

in mg/L

692 1,440 2,520 2,900 6,250 NA NA NA NA 8/2000 2/2001 

Barium, in mg/L 0.33 0.43 0.68 0.78 2.3 NA NA NA NA 8/2000 2/2001 Calcium, in mg/L 58 109 118 158 172 NA NA NA NA 8/2000 2/2001 Sodium, in mg/L 167 366 666 744 1,220 NA NA NA NA 8/2000 2/2001 Chloride, in mg/L 306 821 1,560 1,890 2,870 230 100 NA NA 8/2000 2/2001 Sulfate, in mg/L 30.2 48.0 53.1 66.5 78.1 NA NA NA NA 8/2000 2/2001 

Station 520800030080-01

Dissolved solids, 

in mg/L

1,800 2,020 2,620 2,820 3,990 NA NA NA NA 8/2000 2/2001 

Barium, in mg/L 0.56 0.72 0.78 1.20 2.39 NA NA NA NA 8/2000 2/2001 Calcium, in mg/L 109 111 113 123 165 NA NA NA NA 8/2000 2/2001 Sodium, in mg/L 488 565 691 718 1,220 NA NA NA NA 8/2000 2/2001 Chloride, in mg/L 941 1,120 1,630 2,290 2,430 230 100 NA NA 8/2000 2/2001 Sulfate, in mg/L 48.2 50.6 52.4 53.6 78.1 NA NA NA NA 8/2000 2/2001 
Appendix 5. Summary statistics of surface-water-quality data collected by the Oklahoma Water Resources Board in or near the Citizen Potawatomi NArea, Oklahoma, 1998 through 2005.—Continued [mg/L, milligrams per liter, μg/L, micrograms per liter, μS/cm, microsiemens per centimeter; <, less than; NA, not applicable; Adjusted maximum likelihood estimation used to eswith censored values; highest level of minimum reporting limits used for summary statistics, e, natural exponent; ln, natural logarithm; hardness, hardness in mg/L; CCC, Criteria Environmental Protection Agency, 2010a), Primary contact standards from State of Oklahoma (2007), note that those standards are based on the geometric mean of at least 5 sampperiods, a sampling frequency not obtained for these samples; bacteria counts in colony-forming units per 100 milliliters, all constituents analyzed in unfiltered samples unless notprimary-contact standards from State of Oklahoma (2007] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value CCC Percent of samples in which measure- ment exceeded CCC Primary Body Contact Recreation Standard Percent of samples exceeding Primary Body Contact Recreation Standard Date of first sample (month/ year) Date of last sample (month/ year) N

b

sa

Station 520800030120-01 Dissolved solids, in mg/L 1,260 1,440 2,430 2,960 6,250 NA NA NA NA 8/2000 2/2001 

Barium, in mg/L 0.37 0.40 0.64 0.71 0.90 NA NA NA NA 8/2000 2/2001 Calcium, in mg/L 101 110 148 159 172 NA NA NA NA 8/2000 2/2001 Sodium, in mg/L 345 362 719 765 814 NA NA NA NA 8/2000 2/2001 Chloride, in mg/L 571 798 1,520 1,680 2,870 230 100 NA NA 8/2000 2/2001 Sulfate, in mg/L 47.1 50.0 59.0 63.3 74.5 NA NA NA NA 8/2000 2/2001 
Appendix 6. Summary statistics of surface-water-quality data collected by the Oklahoma Corporation Commission in or near the Citizen PotawatomJurisdictional Area, Oklahoma, 1999 through 2002.—Continued [mg/L, milligrams per liter; L, liter; μS/cm, microsiemens per centimeter; <, less than; μg/L, micrograms per liter; all constituents analyzed in unfiltered samples] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value Date of first sample (month/year) 

Blacksmith Creek

Dissolved solids, in mg/L 1,740 1,810 2,790 3,230 3,840 8/2000 Calcium, in mg/L 101 110 148 159 172 8/2000 Sodium, in mg/L 345 362 719 765 814 8/2000 Chloride, in mg/L 571 798 1,524 1,680 2,870 8/2000 Sulfate, in mg/L 15.7 16.7 20 21 25 8/2000 Chromium, in mg/L 371 398 636 712 900 8/2000 

Blacksmith Creek tributary

Calcium, in mg/L 27.0 118 291 484 3,680 4/2000 Magnesium, in mg/L 13.0 39.0 94.0 124 809 4/2000 Potassium, in mg/L 5.00 13.5 53.0 71.5 588 4/2000 Sodium, in mg/L 88.0 623 2,190 2,740 19,000 4/2000 Bromide, in mg/L 495.0 4,200 13,300 17,300 98,600 4/2000 Chloride, in mg/L 144 1,200 2,970 5,160 39,800 4/2000 Sulfate, in mg/L 6.00 8.50 10.0 30.0 79.0 4/2000 Nitrate as nitrogen, in mg/L <1.0 <1.0 <1.0 <1.0 <1.0 4/2000 

Bruno Creek

Dissolved solids, in mg/L 1,400 1,620 1,850 1,850 1,850 2/1999 Calcium, in mg/L 107 118 130 142 153 2/1999 Magnesium, in mg/L 77.0 77.7 78.5 79.2 80 2/1999 Potassium, in mg/L 6.00 7.25 8.50 9.75 11.0 2/1999 Sodium, in mg/L 630 634 638 642 646 2/1999 Bromide, in mg/L 4,010 4,010 4,010 4,010 4,010 12/2001 Chloride, in mg/L 1,090 1,130 1,180 1,220 1,260 2/1999 Sulfate, in mg/L 28.0 29.5 31.0 32.5 34.0 2/1999 Nitrite plus nitrate as nitrogen, in mg/L <1.00 <1.00 <1.00 1.00 1.00 2/1999 

Canadian River at U.S. Highway 177

Dissolved solids, in mg/L 290 510 523 640 995 5/1999 Calcium, in mg/L 166 168 169 171 174 3/1999 Magnesium, in mg/L 61.0 61.5 62.0 65.0 68.0 3/1999 

Appendix 6. Summary statistics of surface-water-quality data collected by the Oklahoma Corporation Commission in or near the Citizen PotawatomArea, Oklahoma, 1999 through 2002.[mg/L, milligrams per liter; L, liter; μS/cm, microsiemens per centimeter; <, less than; μg/L, micrograms per liter; all constituents analyzed in unfiltered samples]
Appendix 6. Summary statistics of surface-water-quality data collected by the Oklahoma Corporation Commission in or near the Citizen PotawatomJurisdictional Area, Oklahoma, 1999 through 2002.—Continued [mg/L, milligrams per liter; L, liter; μS/cm, microsiemens per centimeter; <, less than; μg/L, micrograms per liter; all constituents analyzed in unfiltered samples] Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value Date of first sample (month/year) 

Canadian River at U.S. Highway 177—Continued Potassium, in mg/L 7.00 7.50 8.00 9.00 10.0 3/1999 

Sodium, in mg/L 116 122 129 130 132 3/1999 Chloride, in mg/L 120 148 172 192 209 3/1999 Sulfate, in mg/L 304 398 456 482 483 3/1999 Chromium, in μg/L 268 280 291.00 328 366 3/1999 

Helsel Creek pH, in standard units 8.1 8.25 8.40 8.50 8.50 2/2002 

Specific conductance, in μS/cm at 25 degrees Celsius 599 606 611 620 630 2/2002 Calcium, in mg/L 56.0 62.0 67.5 71.5 73.0 2/2002 Magnesium, in mg/L 32.0 32.0 34.5 108 321 2/2002 Potassium, in mg/L 1.00 1.00 1.00 1.00 1.00 2/2002 Sodium, in mg/L 12.0 12.8 13.5 14.2 15.0 2/2002 Chloride, in mg/L 10.0 10.8 11.5 12.2 13.0 2/2002 Sulfate, in mg/L 9.00 10.5 13.0 16.2 20.0 2/2002 Nitrite plus nitrate as nitrogen, in mg/L <1.00 <1.00 <1.00 1.00 1.00 2/2002 Boron, in mg/L 0.08 0.10 0.12 0.14 0.16 2/2002 

Pond Creek pH, in standard units 8.10 8.25 8.30 8.38 8.60 2/2002 

Specific conductance, in μS/cm at 25 degrees Celsius 594 599 606 624 666 2/2002 Calcium, in mg/L 49.0 59.5 67.5 74.2 81.0 2/2002 Magnesium, in mg/L 32.0 34.2 36.0 37.0 37.0 2/2002 Potassium, in mg/L 1.0 1.0 1.5 2.0 2.0 2/2002 Sodium, in mg/L 15.0 15.0 16.0 17.2 18.0 2/2002 Chloride, in mg/L 14.0 14.8 16.5 19.0 22.0 2/2002 Sulfate, in mg/L 11.0 11.8 13.5 22.5 45.0 2/2002 Nitrite plus nitrate as nitrogen, in mg/L <1.00 <1.00 1.00 1.00 1.00 2/2002 Boron, in mg/L 0.09 0.10 0.12 0.16 0.20 2/2002 

Pond Creek tributary

Dissolved solids, in mg/L 223 377 472 540 1,100 5/2000 
Appendix 6. Summary statistics of surface-water-quality data collected by the Oklahoma Corporation Commission in or near the Citizen PotawatomJurisdictional Area, Oklahoma, 1999 through 2002.—Continued[mg/L, milligrams per liter; L, liter; μS/cm, microsiemens per centimeter; <, less than; μg/L, micrograms per liter; all constituents analyzed in unfiltered samples]

Constituent name Minimum value 25th percentile 50th percentile 75th percentile Maximum value Date of first sample (month/year) 

Popshego Creek

Dissolved solids, in mg/L 617 2,390 2,860 3,360 3,970 6/2000 Calcium, in mg/L 109 111 113 123 165 8/2000 Sodium, in mg/L 488 565 691 718 1,220 8/2000 Chloride, in mg/L 941 1120 1,630 2,290 2,430 8/2000 Sulfate, in mg/L 16.1 16.9 17.5 17.9 26.1 8/2000 

Salt Creek

Calcium, in mg/L 82.0 92.5 109 124 129 2/1999 Magnesium, in mg/L 42.0 53.2 61.5 66.5 68.0 2/1999 Potassium, in mg/L 6.0 6.0 6.5 7.2 8.0 2/1999 Sodium, in mg/L 155 304 362 371 372 2/1999 Bromide, in mg/L 1,450 1,720 1,990 2,260 2,530 9/1999 Chloride, in mg/L 299 546 674 722 729 2/1999 Sulfate, in mg/L 40.0 55.8 62.5 68.5 82.0 2/1999 Nitrite plus nitrate as nitrogen, in mg/L <1.00 <1.00 <1.00 <1.00 <1.00 2/1999 

Wewoka Creek headwater tributary

Calcium, in mg/L 8,840 9,000 9,160 9,310 9,470 9/2000 Magnesium, in mg/L 2,120 2,160 2,200 2,250 2,290 9/2000 Potassium, in mg/L 812 860 888 926 964 9/2000 Sodium, in mg/L 51,500 53,000 54,500 56,000 57,500 9/2000 Bromide, in mg/L 189,000 192,000 194,000 196,000 199,000 9/2000 Chloride, in mg/L 114,000 118,000 121,000 124,000 128,000 9/2000 Sulfate, in mg/L 511 515 518 522 526 9/2000 Nitrite plus nitrate as nitrogen, in mg/L <1.00 <1.00 <1.00 <1.00 <1.00 9/2000 
Appendix 7. Summary statistics of blank samples associated with surface-water-quality samples, by agency, collected in or near the Citizen PotawaJurisdictional Area, Oklahoma, 1999 through 2011.—Continued [mS/cm, microsiemens per centimeter, mg/L, milligrams per liter; μg/L, micrograms per liter; L, liter; mL, milliliter; <, less than; >, greater than; --, not determined; e, natural exhardness, hardness in mg/L; adjusted maximum likelihood estimation used to estimate statistics for data sets with censored values, CCC, Criteria Continuous Concentration (U.Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”]

Constituent name Minimum value Maximum value Date of first sample (month/year) Date of last sample (month/year) Number of samples Numbe

samples 

detec

measure

U.S. Geological Survey

pH (laboratory), in standard units 8.60 8.70 12/2005 11/2008 2 2 Specific conductance, in μS/cm at 25 degrees Celsius 6.00 7.00 12/2005 11/2008 2 2 Dissolved calcium, in mg/L <0.02 0.17 12/2005 12/2008 3 2 Dissolved magnesium, in mg/L <0.008 <0.012 12/2005 12/2008 3 1 Dissolved potassium, in mg/L <0.06 <0.16 12/2005 12/2008 3 0 Dissolved sodium, in mg/L <0.12 0.59 12/2005 12/2008 3 2 Dissolved chloride, in mg/L <0.12 <0.20 12/2005 12/2008 3 0 Dissolved fluoride, in mg/L <0.08 <0.10 12/2005 12/2008 3 0 Dissolved silica, in mg/L 0.02 2.30 12/2005 12/2008 3 3 Dissolved sulfate, in mg/L <0.18 <0.18 12/2005 12/2008 3 0 Dissolved ammonia plus organic nitrogen, in mg/L as nitrogen <0.02 <0.02 12/2008 12/2009 2 0 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.10 <0.10 12/2009 12/2009 1 0 Dissolved nitrate plus nitrite, in mg/L as nitrogen <0.016 <0.016 12/2008 12/2009 2 0 Dissolved nitrite, in mg/L as nitrogen <0.002 <0.002 12/2009 12/2009 1 0 Dissolved phosphorus, in mg/L <0.006 <0.006 12/2009 12/2009 1 0 Phosphorus, in mg/L <0.008 <0.008 12/2009 12/2009 1 0 

Kickapoo Tribe of Oklahoma

Ammonia, in mg/L as nitrogen <0.1 <0.1 10/2010 7/2011 15 0 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.1 <0.1 10/2010 7/2011 15 0 Nitrate plus nitrite, in mg/L as nitrogen <0.10 0.089 7/2009 7/2011 32 5 Phosphorus, in mg/L <0.20 0.48 7/2009 7/2011 32 2 Escherichia coli. bacteria, in colonies per 100 mL <1 <1 7/2009 7/2011 32 0 

Oklahoma Water Resources Board

Dissolved solids, in mg/L <1 37 5/1999 3/2000 9 3 Hardness, in mg/L as calcium carbonate <5 10 5/1999 3/2000 9 2 Chloride, in mg/L <5 <10 5/1999 8/2005 31 0 Dissolved sulfate, in mg/L <15 30 5/1999 8/2005 32 4 

Appendix 7. Summary statistics of blank samples associated with surface-water-quality samples, by agency, collected in or near the Citizen PotawaJurisdictional Area, Oklahoma, 1999 through 2011.[mS/cm, microsiemens per centimeter, mg/L, milligrams per liter; μg/L, micrograms per liter; L, liter; mL, milliliter; <, less than; >, greater than; --, not determined; e, natural exhardness, hardness in mg/L; adjusted maximum likelihood estimation used to estimate statistics for data sets with censored values, CCC, Criteria Continuous Concentration (U.Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”]
Appendix 7. Summary statistics of blank samples associated with surface-water-quality samples, by agency, collected in or near the Citizen PotawaJurisdictional Area, Oklahoma, 1999 through 2011.—Continued[mS/cm, microsiemens per centimeter, mg/L, milligrams per liter; μg/L, micrograms per liter; L, liter; mL, milliliter; <, less than; >, greater than; --, not determined; e, natural exhardness, hardness in mg/L; adjusted maximum likelihood estimation used to estimate statistics for data sets with censored values, CCC, Criteria Continuous Concentration (U.Agency, 2010a); all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”]

Constituent name Minimum value Maximum value Date of first sample (month/year) Date of last sample (month/year) Number of samples Numbe

samples 

detec

measure

Oklahoma Water Resources Board—Continued

Ammonia, in mg/L as nitrogen <0.05 <0.05 5/1999 8/2005 38 0 Ammonia plus organic nitrogen, in mg/L as nitrogen <0.05 0.10 5/1999 9/2005 45 8 Nitrate, in mg/L as nitrogen <0.05 0.22 5/1999 8/2004 33 2 Nitrite, in mg/L as nitrogen <0.05 0.11 5/1999 8/2004 33 2 Phosphate, in mg/L as phosphorus <0.005 0.016 5/1999 8/2005 32 2 Phosphorus, in mg/L <0.005 0.023 5/1999 8/2005 46 4 Arsenic, in μg/L <10 <10 5/1999 9/2004 13 0 Cadmium, in μg/L <1 <5 5/1999 9/2004 13 0 Cadmium, in μg/L <5 <10 5/1999 9/2004 13 0 Copper, in μg/L <5 <10 5/1999 9/2004 13 0 Lead, in μg/L <3 <10 5/1999 9/2004 13 0 Mercury, in μg/L <0.05 <0.5 5/1999 9/2004 13 0 Nickel, in μg/L <5 <25 5/1999 8/2003 11 0 Selenium, in μg/L <5 <5 5/1999 9/2004 12 0 Silver, in μg/L <1 <10 5/1999 9/2004 13 0 Thallium, in μg/L <3 <10 5/1999 9/2004 13 0 Zinc, in μg/L <5 9.0 5/1999 9/2004 12 1 Enterococci bacteria, in colonies per 100 mL <10 <10 5/2003 6/2004 8 0 Esherichia coli. bacteria, in colonies per 100 mL <10 <10 5/2003 6/2004 8 0 Fecal coliform bacteria, in colonies per 100 mL <10 <10 5/2003 6/2004 8 0 
Appendix 8. Summary statistics of replicate surface-water-quality samples, by agency, collected in or near the Citizen Potawatomi Nation Tribal Jur1988 through 2011. [mg/L, milligrams per liter; L, liter; μS/cm, microsiemens per centimeter; all constituents analyzed in unfiltered samples unless identified as “dissolved” or “filtered”] Constituent name Number of duplicate samples Minimum relative percent difference Median relative percent difference Maximum relative percent difference Date of fi

duplicate s

(month/y

U.S. Geological Survey

pH (laboratory), in standard units 27 0 0 1.2 10/198Specific conductance, in μS/cm at 25 degrees celsius 23 0 0 0 10/198Dissolved ammonia, in mg/L as nitrogen 22 0 42.2 188 9/1988 Dissolved nitrate, in mg/L as nitrogen 16 0.70 15.5 87 8/1989 Dissolved nitrite, in mg/L as nitrogen 20 0 54.5 127 2/1989 Dissolved nitrate plus nitrite, in mg/L as nitrogen 19 0.50 12.6 106 8/1989 Dissolved phosphate, in mg/L as phosphorus 19 0 9.50 66 2/1989 

Kickapoo Tribe of Oklahoma

Ammonia, in mg/L as nitrogen 16 0 0 0 10/201Ammonia plus organic nitrogen, in mg/L as nitrogen 15 0 8.90 185 10/201Nitrate plus nitrite, in mg/L as nitrogen 33 0 1.8 14.7 8/2009 Phosphorus, in mg/L 32 0 3.1 51.2 8/2009 Escherichia coli. bacteria, in colonies per 100 mL 28 0 21.4 106 8/2009 

Oklahoma Water Resources Board

Dissolved solids, in mg/L 34 0 0 17.0 4/1999 Hardness, in mg/L as calcium carbonate 27 0 1.10 18 7/2001 Chloride, in mg/L 34 0 0.75 200 8/2000 Dissolved sulfate, in mg/L 34 0 0.90 186 8/2000 Ammonia, in mg/L as nitrogen 32 0 0 46.2 7/2001 Ammonia plus organic nitrogen, in mg/L as nitrogen 32 0.80 5.90 191 7/2001 Nitrate, in mg/L as nitrogen 24 0 0.90 18.2 7/2001 Nitrite, in mg/L as nitrogen 28 0 0 105 4/1999 Phosphate, in mg/L as phosphorus 34 0 0.90 180 4/1999 Phosphorus, in mg/L 34 0 4.10 195 4/1999 Enterococci bacteria, in colonies per 100 mL 12 0 61.9 181 7/2001 Esherichia coli. bacteria, in colonies per 100 mL 12 0 0 124 7/2001 Fecal coliform bacteria, in colonies per 100 mL 12 0 62.0 187 7/2001 
Appendix 9. Summary statistics of groundwater-quality data collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 1943–2005.—Con[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; <, less than; >, greater than; NA, not applicable, --, not determined; e, natural expohardness, hardness in mg/L; all constituents analyzed in unfiltered samples unless identified as “dissolved”, statistics for data with censored values compute through adjusted ma(AMLE) (Cohn, 2005)]

Constituent name Aquifer Minimum value 25th percentile 50th percentile 75th percentile Maximum value Month of first sample Month of last sample Num- ber of samples

Number of 

samples 

with 

detected 

measurements

sa

Water properties

Dissolved oxygen, 

in mg/L

Alluvial 0.10 2.82 5.20 6.80 10.7 11/1977 6/1990 34 34 Central Oklahoma 0.50 4.48 6.65 8.20 10.4 3/1978 6/2004 136 136 Vamoosa-Ada 1.90 2.95 5.35 4.00 10.3 11/1977 4/1978 11 11 

pH, in standard 

units

Alluvial 5.60 6.4 6.85 7.20 8.40 10/1954 6/1990 80 80 Central Oklahoma 5.10 6.62 7.10 7.40 8.60 12/1951 6/2004 162 162 Vamoosa-Ada 6.30 7.50 7.80 8.35 9.40 7/1951 11/1979 22 22 

Specific 

conductance, in mS/cm at 25 degrees Celsius

Alluvial 79 407 616 884 2,450 6/1947 6/1990 85 85 Central Oklahoma 100 408 595 830 3,660 6/1943 6/2004 168 168 Vamoosa-Ada 400 634 904 1,525 5,600 7/1951 11/1979 22 22 

Water temperature, 

in degrees Celsius

Alluvial 8.40 17.0 18.0 19.0 22.0 6/1947 6/1990 83 83 Central Oklahoma 6.80 13.9 16.0 17.0 21.0 6/1943 6/2004 156 156 Vamoosa-Ada 6.70 12.5 14.3 16.6 20.0 7/1966 11/1979 18 18 

Dissolved solids 

dried at 180 degrees Celsius, in mg/L

Alluvial 212 358 497 635 1,380 6/1947 10/1965 8 8 Central Oklahoma 60.0 170 278 358 1,030 6/1947 3/2005 32 32 Vamoosa-Ada 244 446 699 2,080 3,840 7/1951 11/1979 11 11 

Hardness, in mg/L 

as calcium carbonate

Alluvial 36.6 147 230 330 669 6/1947 6/1990 40 40 Central Oklahoma 6.55 122 197 280 1,530 6/1947 3/2005 173 172 Vamoosa-Ada 6.13 16.0 145 250 565 7/1951 11/1979 23 23 

Alkalinity, in 

mg/L as calcium carbonate

Alluvial 26.0 134 206 322 662 6/1947 7/1989 40 40 Central Oklahoma <15.0 118 205 300 780 6/1943 6/2004 170 167 Vamoosa-Ada 110 240 312 430 801 7/1951 11/1979 23 23 

Appendix 9. Summary statistics of groundwater-quality data collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 1943–2005.[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; <, less than; >, greater than; NA, not applicable, --, not determined; e, natural expohardness, hardness in mg/L; all constituents analyzed in unfiltered samples unless identified as “dissolved”, statistics for data with censored values compute through adjusted ma(AMLE) (Cohn, 2005)]
Appendix 9. Summary statistics of groundwater-quality data collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 1943–2005.—Con[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; <, less than; >, greater than; NA, not applicable, --, not determined; e, natural expohardness, hardness in mg/L; all constituents analyzed in unfiltered samples unless identified as “dissolved”, statistics for data with censored values compute through adjusted ma(AMLE) (Cohn, 2005)] Constituent name Aquifer Minimum value 25th percentile 50th percentile 75th percentile Maximum value Month of first sample Month of last sample Num- ber of samples Number of samples with detected measure- ments 

sa

Major ions Dissolved calcium, in mg/L Alluvial 8.50 28.0 49.2 75.5 180 6/1947 7/1989 36 36 

Central Oklahoma 1.90 28.6 42.0 58.0 575 6/1947 3/2005 153 153 Vamoosa-Ada 1.30 4.28 27.6 59.0 140 7/1951 11/1979 20 20 

Dissolved magnesium, in mg/L Alluvial 3.70 14.0 19.4 43.9 73.5 6/1947 7/1989 36 36 

Central Oklahoma 0.10 13.0 22.0 32.5 95.6 6/1947 3/2005 153 153 Vamoosa-Ada 0.70 2.08 14.5 29.9 52.3 7/1951 11/1979 20 20 

Dissolved potassium, in mg/L Alluvial 0.60 0.70 1.15 2.10 16.0 10/1954 7/1989 18 18 

Central Oklahoma 0.30 0.80 1.38 2.30 16.6 12/1951 3/2005 85 76 Vamoosa-Ada 1.80 1.90 2.40 3.00 7.80 7/1951 11/1979 10 10 

Dissolved sodium, in mg/L Alluvial 5.40 23.0 40.5 78.6 170 10/1954 7/1989 32 32 

Central Oklahoma 3.5 11.0 26.0 84.8 2,290 12/1951 3/2005 153 153 Vamoosa-Ada 6.40 82.0 211 520 1,290 7/2951 11/1979 21 21 

Dissolved bicarbonate, in mg/L Alluvial 32.0 148 238 288 732 6/1947 7/1989 24 24 

Central Oklahoma 44.0 110 218 306 562 6/1943 6/2004 57 57 Vamoosa-Ada 304 510 674 895 915 7/1951 11/1974 5 5 

Dissolved chloride, in mg/L Alluvial 2.40 15.0 26.0 35.5 655 6/1947 7/1989 24 24 

Central Oklahoma 4.50 9.18 15.0 36.0 708 6/1943 3/2005 83 76 Vamoosa-Ada 6.00 15.2 95.5 183 886 7/1951 11/1979 12 12 

Dissolved fluoride, 

in mg/L

Alluvial 0.10 0.10 0.20 0.35 0.90 6/1947 7/1989 20 19 Central Oklahoma 0.10 0.10 0.20 0.30 3.00 6/1947 3/2005 63 54 Vamoosa-Ada 0.40 0.50 1.00 1.00 1.80 9/1979 11/1979 5 5 
Appendix 9. Summary statistics of groundwater-quality data collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 1943–2005.—Con[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; <, less than; >, greater than; NA, not applicable, --, not determined; e, natural expohardness, hardness in mg/L; all constituents analyzed in unfiltered samples unless identified as “dissolved”, statistics for data with censored values compute through adjusted ma(AMLE) (Cohn, 2005)]

Constituent name Aquifer Minimum value 25th percentile 50th percentile 75th percentile Maximum value Month of first sample Month of last sample Num- ber of samples

Number of 

samples 

with 

detected 

measurements

sa

Major ions—Continued

Dissolved sulfate, 

in mg/L

Alluvial 5.00 16.5 30.0 49.5 431 6/1947 7/1989 40 39 Central Oklahoma 3.00 5.11 13.5 29.0 1,900 6/1943 3/2005 175 133 Vamoosa-Ada 5.00 18.0 46.0 260 2,300 7/1951 11/1979 22 21 

Nutrients

Dissolved or total 

nitrate plus nitrite, in mg/L as nitrogen

Alluvial <0.10 0.18 1.30 3.60 7.80 6/1989 7/1989 15 12 Central Oklahoma <0.05 0.20 0.53 2.10 93.5 7/1974 3/2005 59 50 Vamoosa-Ada 0.49 0.490 0.490 0.49 0.49 11/1974 11/1974 1 1 

Dissolved 

phosphorus, in mg/L

Alluvial <0.04 <0.04 <0.04 <0.04 <0.04 11/1977 12/1978 16 0 Central Oklahoma <0.04 0.001 0.005 0.02 0.324 1/1977 4/1978 98 11 Vamoosa-Ada <0.04 <0.04 <0.04 <0.04 <0.04 11/1977 4/1978 11 0 

Metals

Dissolved arsenic, 

in μg/L

Alluvial <0.50 0.163 0.380 1.00 4.70 11/1977 7/1989 31 10 Central Oklahoma <0.50 0.193 0.393 0.800 5.80 1/1977 3/2005 136 48 Vamoosa-Ada <0.50 0.210 0.377 1.00 1.60 11/1977 4/1978 11 4 

Dissolved 

chromium, in μg/L

Alluvial <4.00 <4.00 <4.00 <5.00 8.00 11/1977 7/1989 29 1 Central Oklahoma <4.00 0.054 0.300 1.66 80.0 1/1977 3/2005 133 19 Vamoosa-Ada <4.00 <4.00 <4.00 <4.00 20.0 11/1977 4/1978 11 1 

Dissolved 

chromium (VI) in μg/L

Alluvial NA NA NA NA NA NA NA NA NA Central Oklahoma <1.00 0.528 1.00 1.00 13 4/1988 7/1988 21 12 Vamoosa-Ada NA NA NA NA NA NA NA NA NA 

Dissolved iron, in 

μg/L

Alluvial <10.0 0.692 4.65 14.5 2,800 11/1977 7/1989 31 15 Central Oklahoma <3.00 0.097 0.812 6.79 3,180 9/1954 3/2005 145 36 Vamoosa-Ada <10.0 <10.0 <10.0 <10.0 70.0 7/1951 4/1978 12 2 
Appendix 9. Summary statistics of groundwater-quality data collected in the Citizen Potawatomi Nation Tribal Jurisdictional Area, 1943–2005.—Con[mg/L, milligrams per liter; μS/cm, microsiemens per centimeter; μg/L, micrograms per liter; <, less than; >, greater than; NA, not applicable, --, not determined; e, natural expohardness, hardness in mg/L; all constituents analyzed in unfiltered samples unless identified as “dissolved”, statistics for data with censored values compute through adjusted ma(AMLE) (Cohn, 2005)] Constituent name Aquifer Minimum value 25th percentile 50th percentile 75th percentile Maximum value Month of first sample Month of last sample Num- ber of samples Number of samples with detected measure- ments 

sa

Metals—Continued Dissolved lead, in μg/L Alluvial <10.0 4.48 6.35 8.98 20.0 6/1989 7/1989 15 3 

Central Oklahoma <10 <10 <10 <10 10.0 8/1987 7/1988 27 1 Vamoosa-Ada NA NA NA NA NA NA NA 0 NA 

Dissolved lithium, in μg/L Alluvial 6.00 10.0 12.5 21.0 73.0 11/1977 7/1989 26 26 

Central Oklahoma <4.00 10.0 20.0 20.0 140 11/1977 7/1988 99 98 Vamoosa-Ada <10.0 10.0 20.0 30.0 70.0 11/1977 11/1979 18 17 

Dissolved manganese, in μg/L Alluvial <1 0.355 7.00 210 1,280 11/1977 7/1989 27 16 

Central Oklahoma <1 0.035 0.415 20.0 500 12/1970 3/2005 96 29 Vamoosa-Ada <1 0.158 1.08 35.0 50.0 7/1951 4/1978 8 3 

Dissolved uranium, in μg/L Alluvial <0.200 0.300 1.30 4.60 24.1 6/1947 7/1989 31 25 

Central Oklahoma <0.019 0.300 0.900 4.90 97.6 1/1977 7/1988 124 102 Vamoosa-Ada 0.3 0.700 2.80 10.9 48.2 11/1977 4/1978 11 11 

Dissolved zinc, in μg/L Alluvial <3 10.0 24.0 90.0 1,680 11/1977 7/1989 31 29 

Central Oklahoma <3 10.0 40.0 110 3,400 12/1970 3/2005 131 117 Vamoosa-Ada 10 30.0 80.0 220 750 11/1977 4/1978 10 10 
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Andrews and others—Analysis of Environmental Setting, Surface-Water and Groundwater Data, and Data Gaps, Citizen Potawatomi Nation—SIR 2013–5010

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