U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Report 2009–5267

Prepared in cooperation with the Oklahoma Water Resources Board

Methods for Estimating Flow-Duration and Annual MeanFlow Statistics for Ungaged Streams in Oklahoma
On the cover: Photograph shows Spring Creek near Quapaw, Oklahoma. The photograph was taken by U.S. Geological Survey staff.
Methods for Estimating Flow-Duration and 

Annual Mean-Flow Statistics for Ungaged 

Streams in Oklahoma

By Rachel A. Esralew and S. Jerrod Smith

Prepared in cooperation with the Oklahoma Water Resources Board

Scientific Investigations Report 2009–5267

U.S. Department of the Interior

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

KEN SALAZAR, Secretary

U.S. Geological Survey

Marcia K. McNutt, Director

U.S. Geological Survey, Reston, Virginia: 2010

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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:

Esralew, R.A., Smith, S.J., 2010, Methods for estimating flow-duration and annual mean-flow statistics for ungaged 

streams in Oklahoma: U.S. Geological Survey Scientific Investigations Report 2009-5267, 131 p.
iii

Contents

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

Introduction.....................................................................................................................................................2

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

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

Acknowledgments ................................................................................................................................5

Description of Study Area and Factors that Affect Streamflow in the Study Area ...........................5

Definition of Study Area Boundary ....................................................................................................5

Landscape and Climate Characteristics ..........................................................................................5

Anthropogenic Activities ..................................................................................................................23

Calculation of Flow-Duration and Annual Mean-flow Statistics at Gaging Stations .......................28

Streamflow Data Used for Calculation of Statistics .....................................................................28

Calculation of Statistics .....................................................................................................................29

Methods of Estimating Flow-Duration and Annual Mean-Flow Statistics at Ungaged 

Stream Locations............................................................................................................................30

Drainage-Area Ratio Method ...........................................................................................................30

Regression Equation Method ...........................................................................................................31

Development of Regression Equations to Estimate Flow-Duration and Annual MeanFlow Statistics at Unregulated Ungaged Stream Locations in Oklahoma ............................31

Selection of Data for Use in Regression Analysis .........................................................................31

Selection of Sites and Periods of Record .............................................................................32

Selection and Computation of Drainage-Basin Characteristics ........................................32

Determination of Regression Regions .............................................................................................35

Methods Used to Develop Regression Equations .........................................................................38

Independent Variable Selection .............................................................................................38

Selection of Regression Procedures to Handle Datasets with Zero Flow .......................40

Bias Correction Factors ............................................................................................................41

Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow 

Statistics for Unregulated Ungaged Stream Locations in Oklahoma ....................................42

Independent Variables in Regression Equations ...........................................................................42

Regression Accuracy .........................................................................................................................43

Limitations ............................................................................................................................................46

Example Computations ......................................................................................................................48

Summary .......................................................................................................................................................48

References Cited..........................................................................................................................................50

Tables ...........................................................................................................................................................53

2. Annual, summer-autumn, and winter-spring flow-duration statistics an annual 

mean-flow statistics for selected streamflow gaging stations and periods 

of record..................................................................................................................................55

3. October, November, and December flow-duration statistics for selected streamflowgaging stations and periods of record. ..............................................................................67

4. January, February, and March flow-duration statistics for selected streamflowgaging stations and periods of record. ..............................................................................79
iv

5. April, May, and June flow-duration statistics for selected streamflow-gaging 

stations and periods of record. ...........................................................................................90

6. July, August, and September flow duration statistics for selected streamflowgaging stations and periods of record. ............................................................................101

8. Selected drainage-basin characteristics for streamflow-gaging stations used 

in regression analysis. .......................................................................................................112

9. Regression equations developed to estimate flow-duration statistics and 

annual mean-flow at 32 streamflow gaging stations in Region 1. ..............................120

10. Regression equations developed to estimate flow-duration statistics and 

annual mean-flow at 30 streamflow gaging stations in Region 2. ..............................124

11. Regression equations developed to estimate flow-duration statistics and 

annual mean-flow at 51 streamflow gaging stations in Region 3. ..............................128

Figures

 1–5. Maps showing:

 1. Streamflow-gaging stations with 10 or more years of data where flow-

 duration and annual mean-flow statistics were computed, including stations 

 that were used initially in regression analysis. ................................................................3

 2. Land-surface elevation in Oklahoma and parts of adjacent states. ...........................24

 3. Areas of equal average soil permeability in Oklahoma and parts of adjacent 

 states relative to three regions used in regression analysis, and three 

 regions used for developing regression equations. ......................................................25

 4. Percent forest canopy in Oklahoma and parts of adjacent states relative to 

 three regions used in regression analysis, and three regions used for 

 developing regression equations. ....................................................................................26

 5. Mean-annual precipitation in Oklahoma and parts of adjacent states. ....................27

 6. Graph showing example of a flow-duration curve for Baron Fork at Eldon, Oklahoma 

(U.S. Geological Survey station identifier 07197000, map number 99 on figure 1), 

by using daily streamflow data for the entire period of record, 1949–2007. .....................30

 7–8. Map showing:

 7. Three regions used for developing regression equations relative to boundaries 

 of level III ecoregions of Oklahoma and parts of adjacent states. .............................36

 8. Three regions used for developing regression equations and selected streamflow- 

 gaging stations used to develop final regression equations after outliers 

 were removed. .....................................................................................................................37

 9. Schematic showing process used to develop regressions to estimate flow-duration 

and annual mean-flow statistics at ungaged stream locations in Oklahoma. .................39

 10–12. Graphs showing:

 10. Comparison of the regression estimated and observed (A) annual mean flow 

 and annual (B) 20th, (C) 50th, (D) 80th, (E) 90th, and (F) 95th percentile flow 

 exceedances for streamflow-gaging stations in Region 2. .....................................44

 11. For each regression region in Oklahoma, (A) plots of median flow exceed- 

 ances for datasets used to develop regression equations to estimate annual, 

 seasonal, and monthly flow-duration statistics at ungaged streams and (B) 

 plots of the adjusted coefficient of determination in relation to the log of 

 median flow exceedances for regression datasets.. .................................................45

 12. Example of a flow-duration curve with manual correction for an illogical 

 progression of flow-duration statistics estimated from regression equations. ....49
v

Tables

1. Description of streamflow-gaging stations in and near Oklahoma and 

periods of record where flow-duration and annual mean-flow statistics 

were calculated, and if selected periods of record were used in 

regression equations for estimating flow-duration and annual mean 

flow statistics at ungaged stream locations in Oklahoma.....................................................6

7. Description of drainage-basin characteristics used in regression analysis 

in order to estimate flow-duration and annual mean-flow statistics in Oklahoma. ........33

12. Ranges of validity for basin characteristics used as independent variables 

in development of regressions to estimate flow-duration and annual meanflow statistics for three regions in Oklahoma. .......................................................................47

Conversion Factors and Datums

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

mile (mi) 1.609 kilometer (km)

yard (yd) 0.9144 meter (m)

Area

square mile (mi2

) 2.590 square kilometer (km2) 

Flow rate

cubic foot per second (ft3

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

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).
vi
Abstract

Flow statistics can be used to provide decision makers 

with surface-water information needed for activities such as 

water-supply permitting, flow regulation, and other water 

rights issues. Flow statistics could be needed at any location 

along a stream. Most often, streamflow statistics are needed 

at ungaged sites, where no flow data are available to compute 

the statistics. Methods are presented in this report for estimating flow-duration and annual mean-flow statistics for ungaged 

streams in Oklahoma. 

Flow statistics included the (1) annual (period of record), 

(2) seasonal (summer-autumn and winter-spring), and (3) 12 

monthly duration statistics, including the 20th, 50th, 80th, 

90th, and 95th percentile flow exceedances, and the annual 

mean-flow (mean of daily flows for the period of record). 

Flow statistics were calculated from daily streamflow information collected from 235 streamflow-gaging stations throughout 

Oklahoma and areas in adjacent states.

 A drainage-area ratio method is the preferred method for 

estimating flow statistics at an ungaged location that is on a 

stream near a gage. The method generally is reliable only if 

the drainage-area ratio of the two sites is between 0.5 and 1.5. 

 Regression equations that relate flow statistics to 

drainage-basin characteristics were developed for the purpose 

of estimating selected flow-duration and annual mean-flow 

statistics for ungaged streams that are not near gaging stations 

on the same stream. Regression equations were developed 

from flow statistics and drainage-basin characteristics for 113 

unregulated gaging stations. 

Separate regression equations were developed by using 

U.S. Geological Survey streamflow-gaging stations in regions 

with similar drainage-basin characteristics. These equations 

can increase the accuracy of regression equations used for 

estimating flow-duration and annual mean-flow statistics at 

ungaged stream locations in Oklahoma. Streamflow-gaging 

stations were grouped by selected drainage-basin characteristics by using a k-means cluster analysis. Three regions 

were identified for Oklahoma on the basis of the clustering of 

gaging stations and a manual delineation of distinguishable 

hydrologic and geologic boundaries: Region 1 (western Oklahoma excluding the Oklahoma and Texas Panhandles), Region 

2 (north- and south-central Oklahoma), and Region 3 (eastern 

and central Oklahoma). 

A total of 228 regression equations (225 flow-duration 

regressions and three annual mean-flow regressions) were 

developed using ordinary least-squares and left-censored 

(Tobit) multiple-regression techniques. These equations can 

be used to estimate 75 flow-duration statistics and annual 

mean-flow for ungaged streams in the three regions. Drainage-basin characteristics that were statistically significant 

independent variables in the regression analyses were (1) 

contributing drainage area; (2) station elevation; (3) mean 

drainage-basin elevation; (4) channel slope; (5) percentage of 

forested canopy; (6) mean drainage-basin hillslope; (7) soil 

permeability; and (8) mean annual, seasonal, and monthly 

precipitation. 

The accuracy of flow-duration regression equations 

generally decreased from high-flow exceedance (low-exceedance probability) to low-flow exceedance (high-exceedance 

probability) . This decrease may have happened because a 

greater uncertainty exists for low-flow estimates and low-flow 

is largely affected by localized geology that was not quantified 

by the drainage-basin characteristics selected. 

The standard errors of estimate of regression equations 

for Region 1 (western Oklahoma) were substantially larger 

than those standard errors for other regions, especially for 

low-flow exceedances. These errors may be a result of greater 

variability in low flow because of increased irrigation activities in this region.

Regression equations may not be reliable for sites where 

the drainage-basin characteristics are outside the range of 

values of independent variables used to develop the equations. 

The equations are not accurate for streams that are regulated 

by water-supply reservoirs, streams that are affected by 

local irrigation activity, or streams that are affected by urban 

change. 

Methods for Estimating Flow-Duration and Annual MeanFlow Statistics for Ungaged Streams in Oklahoma

By Rachel A. Esralew and S. Jerrod Smith
2 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Introduction

Successful management of reservoir operations, permitting for stream withdrawals, and maintenance of water-quality 

standards are supported by knowledge of the magnitude 

of flow that can be expected in a stream at any given time. 

Flow-duration statistics that describe the percentage of time a 

stream discharge is equaled or exceeded, and annual meanflow statistics (mean of annual daily flow), commonly are used 

by State agencies and other water-resources managers to help 

effectively manage Oklahoma surface-water resources (R.S. 

Fabian, Oklahoma Water Resources Board, oral and written 

communication, June 2007). 

The historic continuous daily streamflow information collected at U.S. Geological Survey (USGS) streamflow-gaging 

stations provides a valuable resource for estimating flow 

statistics during a range of temporal circumstances, including 

annual, monthly, and seasonal time periods. This information can be calculated at streamflow-gaging stations where 

long-term daily streamflow record is available, generally 10 

or more years of record, and is the criteria used in previous 

studies in Oklahoma (Heimann and Tortorelli, 1987; Tortorelli, 

2002; Lewis and Esralew, 2009). The Interagency Advisory 

Committee on Water Data also recommends at least 10 years 

of data for computation of long-term streamflow statistics 

(Interagency Advisory Committee on Water Data, 1982). The 

USGS has collected daily streamflow at 235 gaging stations in 

the study area for 10 or more years (fig. 1).

The number and location of long-term gaging stations 

is limited in any given drainage-basin by user priorities and 

geographical constraints. The operation of a long-term gaging 

station at every location where streamflow is needed is not 

feasible. Because of the need for estimating flow-duration 

and annual mean-flow statistics for ungaged stream locations 

in Oklahoma, the USGS, in cooperation with the Oklahoma 

Water Resources Board (OWRB), investigated methods for 

estimating long-term streamflow statistics at ungaged stream 

locations. 

Streamflow information can be extrapolated for an 

ungaged stream location near a gaging station on the same 

stream reach, from the gaging-station record, to estimate the 

flow statistics. The drainage-area ratio method is the preferred 

method for estimating flow statistics (Ries and Friezs, 2000). 

However, alternative methods are needed in Oklahoma to 

estimate flow statistics at ungaged stream locations that are not 

near gaging stations. Statistics calculated at gaging stations 

with long-term daily mean-streamflow record are highly variable at in any given drainage basin. Streamflow statistics are 

strongly related to physical drainage-basin characteristics such 

as size, topography, geology, land-cover, and climate (Ries and 

others, 2008). Regression equations that describe the relation 

of physical drainage-basin characteristics to streamflow can be 

developed to estimate streamflow statistics at ungaged stream 

locations for flow-duration and annual mean-flow statistics.

One of the challenges involved with developing regression equations that accurately describe flow is selection of the 

appropriate independent variables. Drainage-basin characteristics that influence streamflow variability such as contributing drainage area, drainage-basin hillslope and main-channel 

slope, soil permeability, forested area, and mean annual, 

seasonal, and monthly precipitation, vary across Oklahoma. 

The influence that these variables have on streamflow 

also may vary across Oklahoma. For example, streamflow 

may be affected by the amount of forested area in some drainage basins in eastern Oklahoma that are heavily forested, but 

forested area may not have a strong influence on streamflow 

in most drainage basins in less forested western Oklahoma. 

Selection of independent variables for regression equations 

that account for the variation in streamflow statistics for the 

entire state may be difficult and may result in regression estimates that have high error.

 Regression equations can be developed for smaller, more 

homogeneous regions to minimize the error of streamflow estimates (Haan, 1977). Statistical methods can be used to group 

gaging stations with similar physical drainage-basin characteristics, as has been done for other studies (Hortness and 

Berenbrock, 2001; Risley and others, 2008). Statistical stream 

groupings can be defined by grouping streams with similar 

drainage-basin characteristics through statistical analysis and 

visual inspection to define regression regions for Oklahoma. 

Comparison of regional regression equations, in terms of 

differences in independent variable selection and regression 

accuracy, can be used to evaluate and provide context for differences in streamflow variability in Oklahoma as a function 

of these drainage-basin characteristics. 

Purpose and Scope

The purpose of this report is to document the methods 

and results of a study designed to estimate flow-duration statistics (annual, seasonal, and monthly) and annual mean flow 

for ungaged streams in Oklahoma. This report includes (1) a 

description of the study area and how variability of physical 

characteristics and anthropogenic activities may affect streamflow, (2) a summary of calculated flow-duration and annual 

mean-flow statistics at gaging stations with long-term (10 or 

more years) daily streamflow data, (3) a summary of available 

methods for estimating flow statistics at ungaged sites, (4) a 

description of the data and methods used to develop regression 

equations for estimating flow-duration and annual mean-flow 

statistics, and (5) a discussion of the results of the regression 

analysis, including the selection of independent variables, 

accuracy and limitations, and an example computation.

The regression equations presented in this report are only 

applicable to streams in Oklahoma and near the Oklahoma 

state line. However, the methods documented in this report 

can be applied elsewhere by using USGS streamflow data 

that are available from gaging stations throughout the United 

States.
COLORADO KANSAS

100°

103°

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15 17 #

18 !# 21 3 # 44

111 # # 116 #4 113 ! # 10

!# ! !# 22 6 7 # # Salt

#117 Fork 2 112 # # # 115 # 118 ##

Cimarron

8

121 23

122 #

NEW 1# ! 1 120 # # 25 #

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!# 29 ! 13 12 #

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!# !# 133 # # #181 # 160 ! # # # 126 !# # !# 180 !# !184 131 161 183 # 102 127 ! # # 130 # 128 129 159 W

# 186 !

ashita

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106 13 !# 187 189 !# # !# # 164 !# ! ! # 195 107

!# 185 165 188 103 # 156 196 104 !# # 108

!# 190 193 #!# !# # 105 166 !# # #! !# ! # # ! # !# !191 ! ! # 198 10

197

TEXAS

0 25 50 MILES

EXPLANATION

0 50 KILOMETERS

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# 192 194 201 199

!# !# 151 168 153 167 !# # 172 # 200 152 # 202 158 # 174 # 203 !# # 169 !# 154

!# 171 !# 155 173 204

175

# 205 ! !# !#

170 # 206

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176

#

178 #

8-digit Hydrologic Unit (HU) boundary

State boundary

Arkansas-Red River basin divide

Stream

# Streamflow-gaging station and map number

! Streamflow-gaging station used in regression analysis to

produce regional regression equations and map number

Red

Riv #

!#

!#

Upper Cimarron Basin !#

Upper Beaver/North Canadian Basin !#

14

22

MISSOURI

ARKANSAS

Albers Equal-Area Conic Projection

North American Datum 1983

8-digit HU boundaries from Natural

Resources Conservation Service

Watershed Boundary Dataset

33°

94°

31°

64 70 # !# ! !# # 41 69

!# 68 !# 40 !# 67

73 71

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48 47 75 # !# 49 76 # !# 81 #77 55 53 !# 50 !# # 51 !#!# # 78 # 79

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60 43 93 82 94

56 !#57 52 84 !# # !# 62 !# 92 58 # !# # ## #83 ## !# # # 89 ! ! # #63 95 59 91!## !# # 61 !

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# !# ! !# !# 213 !# 222 208 214 221 !# 226 233 234 227 !# 231 !# !# 209 #215 230 !# !# #!

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er

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Figure 1. Streamflow-gaging stations with 10 or more years of data where flow-duration and annual mean-flow statistics were computed, including stations that were used initially in regression analysis.
4 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma
Description of Study Area and Factors that Affect Streamflow in the Study Area 5

Regression equations and computed flow-duration and 

annual mean-flow statistics at gaging stations are integrated 

into the USGS StreamStats Web-based tool available at 

http://water.usgs.gov/osw/streamstats/index.html. StreamStats allows users to obtain flow statistics, drainage-basin 

characteristics, and other information for user-selected stream 

sites. The user can ‘point and click’ on a stream location or 

a GIS-based interactive map of Oklahoma and StreamStats 

will delineate the drainage-basin upstream from the selected 

location, compute drainage-basin characteristics, and compute 

flow statistics at the ungaged stream locations by using regression estimates. The user also can ‘point and click’ on USGS 

gaging stations and receive flow statistics and information 

about those stations. 

Previous Investigations

A study by Lewis and Esralew (2009) determined annual 

flow-duration statistics for the 1-, 2-, 5-, 10-, 15-, 20-, 30-, 

40-, 50- (median), 60-, 70-, 80-, 90-, 95-, 98- and 99-percent 

exceedance probabilities, and annual mean-flow (the mean of 

all daily flows for the period of record), for gaging stations in 

and near Oklahoma that had long-term streamflow record (10 

or more years) through 2007. The methods used in this study 

for determining flow-duration and annual mean-flow statistics 

are the same as that described in Lewis and Esralew (2009).

Regression equations that relate streamflow statistics to 

drainage-basin characteristics have been developed in previous investigations. Studies were completed, in Oklahoma, 

to estimate peak-flow frequency statistics at ungaged stream 

locations with a drainage area less than 2,510 square miles 

(Tortorelli and Bergman, 1985; Tortorelli, 1997). Methods 

for developing regression equations to estimate flow-duration 

and annual mean-flow statistics at ungaged stream locations 

by using drainage-basin characteristics were similar to those 

methods used by Risley and others (2008) for Oregon, Perry 

and others (2004) for Kansas, Hortness and Berenbrock (2001) 

for Idaho, and Ries and Friesz (2000) for Massachusetts. 

Acknowledgments

The authors would like to thank Jery Stedinger (Cornell 

University), Stacey Archfield, Julie Kiang, Charles Perry, John 

Risley, and Adam Stonewall (U.S. Geological Survey) for providing knowledge and expertise regarding the methods used 

in the regression analysis. The authors would like to thank 

Robert Tortorelli, U.S. Geological Survey, for working with 

the OWRB to obtain support for the study, and for providing 

his knowledge and expertise regarding flow statistics, regression methods, and gaging history. The authors would like to 

thank Robert Blazs, Tony Coffey, David Adams, and Dale 

Boyle for helping with questions about historic gage records, 

and all U.S. Geological Survey staff, who have collected and 

processed historic streamflow data. The authors also appreciate the efforts of Seth Tribbey and Jason R. Masoner (U.S. 

Geological Survey), who assisted with spatial data preprocessing. The authors also greatly appreciate the help of Alan H. 

Rea, Kenneth D. Skinner, and Kernell G. Ries (U.S. Geological Survey) who provided technical support and solutions to 

many problems with computing drainage-basin characteristics 

and creation of the StreamStats web application.

Description of Study Area and Factors 

that Affect Streamflow in the Study 

Area 

Flow statistics and drainage-basin characteristics were 

computed at selected gaging stations in Oklahoma and adjacent areas of Arkansas, Kansas, Missouri, and Texas. The 

study area includes a wide range of physiographic and climatic 

characteristics that contribute to streamflow variability 

throughout Oklahoma. 

Definition of Study Area Boundary

Streams selected for this study included those streams 

that are in 8-digit hydrologic unit (HU) boundaries in Oklahoma or are in HU boundaries adjacent to the Oklahoma 

state border (fig. 1, table 1). Streams selected for regression 

analysis have drainage-basin areas completely in these 8-digit 

HU boundaries. These boundaries were used because the 

digitally preprocessed drainage-basin characteristic variables 

in the regression equations were only available for this area 

(S.J. Smith and R.A. Esralew, U.S. Geological Survey, written 

commun., 2009). Drainage-basin characteristics could not be 

computed for gaging stations that were along main stems of 

the largest river systems in the state (the Arkansas, Canadian, 

Cimarron, Neosho, Red, and Verdigris Rivers), because the 

drainage areas extend outside of the study area (S.J. Smith 

and R.A. Esralew, U.S. Geological Survey, written commun., 

2009). 

Landscape and Climate Characteristics 

Oklahoma has diverse physical and climatic characteristics that can affect streamflow. Statistics calculated from data 

collected from gaging stations in the study area are related 

to physical and climatic characteristics of the drainage basin 

such as drainage-basin size, topography, land cover, and 

climate. Drainage-basin characteristics that describe drainage 

area, drainage-basin hillslope, channel slope, soil permeability, drainage-basin and station elevation, mean precipitation, 

and forested area were considered as independent variables 

in regression equations to estimate flow-duration and annual 

mean-flow statistics at ungaged sites. 

Contributing drainage area is considered the drainagebasin area that can contribute runoff to the stream location of 
6 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees)

1 07146500 Arkansas River at Arkansas City, Kans. 37.06 -97.06 11030013 36,100 No

U 1922-1942 No

R 1943-2007 No

2 07148140 Arkansas River near Ponca City, Okla. 36.69 -96.93 11060001 38,900 No

R 1977-1993 No

3 07148350 Salt Fork Arkansas River near Winchester, 

Okla.

36.96 -98.78 11060002 827 Yes

U 1960-1993 Yes

4 07148400 Salt Fork Arkansas River near Alva, Okla. 36.82 -98.65 11060002 982 Yes

U 1938-1951, 1980-

2007

Yes

5 07149000 Medicine Lodge River near Kiowa, Kans. 37.04 -98.47 11060003 885 Yes

U 1938-1950, 1955, 

1960-2007

Yes

6 07149500 Salt Fork Arkansas River near Cherokee, 

Okla.

36.82 -98.32 11060004 2,360 Yes

U 1941-1950 Yes

7 07150500 Salt Fork Arkansas River near Jet, Okla. 36.75 -98.13 11060004 3,190 Yes

R 1942-1993 No

8 07151000 Salt Fork Arkansas River at Tonkawa, Okla. 36.67 -97.31 11060004 4,520 Yes

R 1942-2007 No

9 07151500 Chikaskia River near Corbin, Kans. 37.13 -97.60 11060005 813 Yes

U 1950-1965, 1976-

2007

Yes

10 07152000 Chikaskia River near Blackwell, Okla. 36.81 -97.28 11060005 1,870 Yes

U 1936-2007 Yes

11 07152500 Arkansas River at Ralston, Okla. 36.50 -96.73 11060006 46,900 No

U 1926-1975 No

R 1977-2007 No

12 07153000 Black Bear Creek at Pawnee, Okla. 36.34 -96.80 11060006 538 Yes

U 1945-2007 Yes

13 07153100 Ranch Creek at Cleveland Dam near Cleveland, Okla. 36.28 -96.58 11060006 21.9 Yes

R 1945-1963 No

14 07154500 Cimarron River near Kenton, Okla. 36.93 -102.96 11040001 1,110 Yes

U 1951-1966 No4

UI 1971-2007 No
Description of Study Area and Factors that Affect Streamflow in the Study Area 7

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

15 07155000 Cimarron River above Ute Creek near Boise 

City, Okla.

36.91 -102.62 11040002 1,970 Yes

U 1943-1954 No4

16 07155590 Cimarron River near Elkhart, Kans. 37.12 -101.90 11040002 2,800 Yes

U 1971-1981 No4

UI 1983-2007 No

17 07156900 Cimarron River near Forgan, Okla. 37.01 -100.49 11040006 4,220 Yes

U 1966-1977 No4

UI 1983-1986, 1988-

2007

No

18 07157000 Cimarron River near Mocane, Okla. 36.98 -100.31 11040006 4,310 No

U 1943-1965 No

19 07157500 Crooked Creek near Englewood, Kans. 37.03 -100.21 11040007 822 Yes

U 1943-1963 No4

UI 1983-2007 No4

20 07157900 Cavalry Creek near Coldwater, Kans. 37.27 -99.35 11040008 41.5 Yes

U 1967-1981 No4

21 07157950 Cimarron River near Buffalo, Okla. 36.85 -99.32 11050001 7,190 No

U 1960-1994, 2002-

2007

No

22 07157960 Buffalo Creek near Lovedale, Okla. 36.77 -99.37 11050001 401 Yes

U 1967-1993 No5

23 07158000 Cimarron River near Waynoka, Okla. 36.52 -98.88 11050001 8,500 No

U 1938-2007 No

24 07158400 Salt Creek near Okeene, Okla. 36.10 -98.19 11050002 181 Yes

U 1961-1967, 1975-

1979

Yes

25 07159000 Turkey Creek near Drummond, Okla. 36.32 -98.00 11050002 255 Yes

U 1948-1970 No5

26 07159100 Cimarron River near Dover, Okla. 35.95 -97.91 11050002 10,800 No

U 1974-2007 No

27 07159750 Cottonwood Creek near Seward, Okla. 35.81 -97.48 11050002 320 Yes

U 1973-1982, 1990-

2002

Yes
8 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 28 07160000 Cimarron River near Guthrie, Okla. 35.92 -97.43 11050002 12,000 No

U 1938-1976, 1984-

2007

No

29 07160350 Skeleton Creek at Enid, Okla. 36.38 -97.80 11050002 70 Yes UUrb 1996-2007 No

30 07160500 Skeleton Creek near Lovell, Okla. 36.06 -97.59 11050002 412 Yes

U 1950-2007 Yes

31 07163000 Council Creek near Stillwater, Okla. 36.12 -96.87 11050003 30 Yes

U 1934-1993 No5

32 07163500 Cimarron River at Oilton, Okla. 36.09 -96.58 11050003 13,700 No

U 1935-1945 No

33 07164000 Cimarron River at Mannford, Okla. 36.16 -96.40 11050003 13,900 No

U 1939-1950, 1960-

1963

No

34 07164500 Arkansas River at Tulsa, Okla. 36.14 -96.01 11110101 62,100 No

U 1926-1964 No

R 1965-2007 No

35 07164600 Joe Creek at 61st Street at Tulsa, Okla. 36.08 -95.96 11110101 11.6 Yes UUrb 1989-2007 No

36 07165500 Polecat Creek below Heyburn Reservoir near 

Heyburn, Okla.

35.95 -96.29 11110101 123 Yes

R 1951-1979 No

37 07165562 Haikey Creek at 101st Street South at Tulsa, 

Okla.

36.02 -95.85 11110101 17.9 Yes UUrb 1988-2007 No

38 07165565 Little Haikey Creek at 101st Street South at 

Tulsa, Okla.

36.02 -95.86 11110101 5.48 Yes UUrb 1988-2007 No

39 07165570 Arkansas River near Haskell, Okla. 35.82 -95.64 11110101 62,900 No

R 1973-2007 No

40 07170500 Verdigris River at Independence, Kans. 37.22 -95.68 11070103 2,890 No

U 1895-1903, 1922-

1959

No

R 1967-2007 No

41 07170700 Big Creek near Cherryvale, Kans. 37.27 -95.47 11070103 36.8 Yes

U 1958-1980 Yes

R 1982-2007 No
Description of Study Area and Factors that Affect Streamflow in the Study Area 9

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

42 07171000 Verdigris River near Lenapah, Okla. 36.85 -95.59 11070103 3,640 No

U 1939-1959 No

R 1967-2007 No

43 07171400 Verdigris River near Oologah, Okla. 35.50 -97.19 11070105 4,340 No

R 1964-1992 No

44 07172000 Caney River near Elgin, Kans. 37.00 -96.32 11070106 429 Yes

U 1940-2007 Yes

45 07173000 Caney River near Hulah, Okla. 36.93 -96.09 11070106 711 Yes

U 1938-1993 Yes

46 07174200 Little Caney River below Cotton Creek near 

Copan, Okla.

36.90 -95.97 11070106 503 Yes

U 1944-1981 Yes

47 07174400 Caney River above Coon Creek at Bartlesville, Okla. 36.76 -95.97 11070106 1,390 Yes

R 1986-2007 No

48 07174600 Sand Creek at Okesa, Okla. 36.72 -96.13 11070106 138 Yes

U 1960-1993 Yes

49 07174700 Caney River near Ochelata, Okla. 36.64 -95.93 11070106 1,750 Yes

R 1957-1976 No

50 07175000 Double Creek near Ramona, Okla. 36.51 -95.94 11070106 2.45 Yes

U 1954-1969 No5

51 07175500 Caney River near Ramona, Okla. 36.51 -95.84 11070106 1,960 Yes

R 1984-2007 No

52 07176000 Verdigris River near Claremore, Okla. 36.31 -95.70 11070105 6,530 No

U 1936-1962 No

R 1964-2007 No

53 07176465 Birch Creek below Birch Lake near Barnsdall, Okla. 36.53 -96.16 11070107 66 Yes

R 1978-1992 No

54 07176500 Bird Creek at Avant, Okla. 36.49 -96.06 11070107 369 Yes

U 1945-1976 Yes

R 1978-2007 No

55 07176800 Candy Creek near Wolco, Okla. 36.54 -96.05 11070107 31.4 Yes

U 1970-1981 Yes

56 07177000 Hominy Creek near Skiatook, Okla. 36.35 -96.11 11070107 340 Yes

U 1944-1981 Yes
10 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 57 07177500 Bird Creek near Sperry, Okla. 36.28 -95.95 11070107 907 Yes

U 1939-1984 Yes

R 1985-2007 No

58 07177650 Flat Rock Creek at Cincinnati Avenue at 

Tulsa, Okla.

36.22 -96.00 11070107 8.11 Yes UUrb 1988-2007 No

59 07177800 Coal Creek at Tulsa, Okla. 36.19 -95.91 11070107 8.23 Yes UUrb 1988-2007 No

60 07178000 Bird Creek near Owasso, Okla. 36.25 -95.87 11070107 1,020 Yes

R 1987-2007 No

61 07178040 Mingo Creek at 46th Street North at Tulsa, 

Okla.

36.22 -95.86 11070107 58.8 Yes UUrb 1987-1997 No

62 07178200 Bird Creek at State Highway 266 near Catoosa, Okla. 36.22 -95.82 11070107 1,100 Yes

R 1989-2007 No

63 07178600 Verdigris River near Inola, Okla. 36.16 -95.62 11070105 7,910 No

U 1944-1962 No

64 07184000 Lightning Creek near McCune, Kans. 37.28 -95.03 11070205 196 Yes

U 1939-1946, 1960-

2007

Yes

65 07185000 Neosho River near Commerce, Okla. 36.93 -94.96 11070206 5,880 No

U 1939-1962 No

R 1964-2007 No

66 07185095 Tar Creek at 22nd Street Bridge at Miami, 

Okla.

36.90 -94.87 11070206 44.7 Yes UUrb 1984-1993, 2005-

2007

No

67 07185500 Stahl Creek near Miller, Mo. 37.19 -93.84 11070207 4.02 Yes

U 1950-1976 Yes

68 07185700 Spring River at LaRussell, Mo. 37.15 -94.06 11070207 306 Yes

U 1958-1973, 1976-

1980

Yes

69 07185765 Spring River at Carthage, Mo. 37.19 -94.33 11070207 448 Yes

U 1967-1980, 2002-

2007

Yes

70 07186000 Spring River near Waco, Mo. 37.25 -94.57 11070207 1,160 Yes

U 1924-2007 Yes
Description of Study Area and Factors that Affect Streamflow in the Study Area 11

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

71 07186400 Center Creek near Carterville, Mo. 37.14 -94.38 11070207 229 Yes

U 1962-1991 No5

72 07187000 Shoal Creek above Joplin, Mo. 37.02 -94.52 11070207 427 Yes

U 1942-2007 Yes

73 07187500 Shoal Creek near Joplin, Mo. 37.03 -94.54 11070207 442 Yes

U 1925-1941 No5

74 07188000 Spring River near Quapaw, Okla. 36.93 -94.75 11070207 2,520 Yes

U 1939-2007 Yes

75 07188500 Lost Creek at Seneca, Mo. 36.84 -94.61 11070206 40.8 Yes

U 1949-1959 No5

76 07189000 Elk River near Tiff City, Mo. 36.63 -94.59 11070208 851 Yes

U 1940-2007 Yes

77 07189500 Neosho River near Grove, Okla. 36.61 -94.82 11070206 9,970 No

U 1925-1939 No

78 07189540 Cave Springs Branch near South West City, 

Mo.

36.55 -94.62 11070206 8 Yes

U 1998-2007 Yes

79 07189542 Honey Creek near South West City, Mo. 36.55 -94.68 11070206 48.6 Yes

U 1998-2007 Yes

80 07190500 Neosho River near Langley, Okla. 36.44 -95.05 11070209 10,300 No

R 1940-2007 No

81 07191000 Big Cabin Creek near Big Cabin, Okla. 36.57 -95.15 11070209 450 Yes

U 1948-2007 Yes

82 07191220 Spavinaw Creek near Sycamore, Okla. 36.33 -94.64 11070209 132 Yes

U 1962-2007 Yes

83 07191500 Neosho River near Chouteau, Okla. 36.23 -95.18 11070209 11,500 No

R 1965-2007 No

84 07192000 Pryor Creek near Pryor, Okla. 36.28 -95.33 11070209 227 Yes

U 1948-1963 Yes

85 07192500 Neosho River near Wagoner, Okla. 35.93 -95.27 11070209 12,300 No

R 1940-1949 No

86 07193500 Neosho River below Fort Gibson Lake near 

Fort Gibson, Okla.

35.85 -95.23 11070209 12,500 No

R 1954-1989 No

87 07194500 Arkansas River near Muskogee, Okla. 35.77 -95.30 11110102 84,100 No

U 1926-1952 No

R 1965-1970, 2004-

2007

No
12 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 88 07194800 Illinois River at Savoy, Ark. 36.10 -94.34 11110103 167 Yes

U 1979-1980, 1986, 

1996-2007

Yes

89 07195000 Osage Creek near Elm Springs, Ark. 36.22 -94.29 11110103 130 Yes

U 1951-1975, 1976-

2007

Yes

90 07195430 Illinois River South of Siloam Springs, Ark. 36.11 -94.53 11110103 568 Yes

U 1995-2006 Yes

91 07195500 Illinois River near Watts, Okla. 36.13 -94.57 11110103 630 Yes

U 1955-2007 Yes

92 07195800 Flint Creek at Springtown, Ark. 36.26 -94.43 11110103 14.7 Yes

U 1961-2007 Yes

93 07195855 Flint Creek near West Siloam Springs, Okla. 36.22 -94.60 11110103 59.8 Yes

R 1980-2007 No

94 07195865 Sager Creek near West Siloam Springs, Okla. 36.20 -94.61 11110103 19.1 Yes

U 1996-2007 Yes

95 07196000 Flint Creek near Kansas, Okla. 36.19 -94.71 11110103 116 Yes

U 1956-1990, 1993-

2007

Yes

96 07196500 Illinois River near Tahlequah, Okla. 35.92 -94.92 11110103 950 Yes

U 1936-2007 Yes

97 07196900 Baron Fork at Dutch Mills, Ark. 35.88 -94.49 11110103 41.1 Yes

U 1958-2007 Yes

98 07196973 Peacheater Creek at Christie, Okla. 35.95 -94.70 11110103 24.9 Yes

U 1992-2003 Yes

99 07197000 Baron Fork at Eldon, Okla. 35.92 -94.84 11110103 312 Yes

U 1949-2007 Yes

100 07197360 Caney Creek near Barber, Okla. 35.78 -94.86 11110103 90.2 Yes

U 1998-2007 Yes

101 07198000 Illinois River near Gore, Okla. 11110103 1,610 Yes

U 1939-1951 Yes

35.57 -95.07

R 1953-2007 No

102 07228500 Canadian River at Bridgeport, Okla. 35.54 -98.32 11090202 20,500 No

U 1945-1964 No

R 1970-2007 No

103 07229100 Canadian River near Noble, Okla. 35.08 -97.38 11090202 21,100 No

R 1965-1975 No
Description of Study Area and Factors that Affect Streamflow in the Study Area 13

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

104 07229200 Canadian River at Purcell, Okla. 35.01 -97.35 11090202 21,100 No

R 1980-2007 No

105 07229300 Walnut Creek at Purcell, Okla. 35.00 -97.37 11090202 202 Yes

U 1966-1993 Yes

106 07230000 Little River below Lake Thunderbird near 

Norman, Okla.

35.22 -97.21 11090203 257 Yes

U 1953-1964 No5

R 1966-2007 No

107 07230500 Little River near Tecumseh, Okla. 35.17 -96.93 11090203 463 Yes

U 1944-1964 Yes

R 1966-2007 No

108 07231000 Little River near Sasakwa, Okla. 34.97 -96.51 11090203 888 Yes

U 1943-1961 Yes

R 1966-2007 No

109 07231500 Canadian River at Calvin, Okla. 34.98 -96.24 11090202 23,200 No

U 1906-1964 No

R 1965-2007 No

110 07232000 Gaines Creek near Krebs, Okla. 34.98 -95.62 11090204 585 Yes

U 1943-1963 No6

111 07232500 Beaver River near Guymon, Okla. 36.72 -101.49 11100101 1,610 Yes

U 1938-1971 No4

UI 1978-1993 No

112 07232900 Coldwater Creek near Guymon, Okla. 36.57 -101.38 11100103 960 Yes UI 1981-2007 No113 07233000 Coldwater Creek near Hardesty, Okla. 36.64 -101.21 11100103 1,030 Yes

U 1940-1964 No4

114 07233500 Palo Duro Creek near Spearman, Texas 36.20 -101.31 11100104 625 Yes

U 1944-1971 No4

115 07233650 Palo Duro Creek at Range, Okla. 36.54 -101.08 11100104 826 Yes

R 1992-2007 No

116 07234000 Beaver River at Beaver, Okla. 36.82 -100.52 11100201 4,990 Yes

U 1938-1971 No4

RI 1979-2007 No
14 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 117 07234100 Clear Creek near Elmwood, Okla. 36.65 -100.50 11100201 162 Yes

U 1966-1993 No4

118 07234500 Beaver River near Fort Supply, Okla. 36.59 -99.59 11100201 6,540 Yes

U 1938-1950 No4

119 07235000 Wolf Creek at Lipscomb, Texas 36.24 -100.28 11100203 475 Yes

R 1962-1971 No

RI 1978-2007 No

120 07236000 Wolf Creek near Fargo, Okla. 36.40 -99.62 11100203 1,470 Yes

U 1943-1958 No4

121 07237000 Wolf Creek near Fort Supply, Okla. 36.57 -99.55 11100203 1,500 Yes

R 1943-1971 No

RI 1978-1993 No

122 07237500 North Canadian River at Woodward, Okla. 36.44 -99.28 11100301 8,380 Yes

U 1939-1971 Yes

RI 1979-2007 No

123 07238000 North Canadian River near Seiling, Okla. 36.18 -98.92 11100301 9,060 Yes

U 1947-1971 Yes

RI 1979-2007 No

124 07239000 North Canadian River at Canton, Okla. 36.08 -98.60 11100301 9,290 Yes

U 1938-1947 No5

R 1949-1993, 2001-

2002

No

125 07239300 North Canadian below Weavers Creek near 

Watonga, Okla.

35.81 -98.42 11100301 7,840 Yes

R 1984-2007 No

126 07239450 North Canadian River near Calumet, Okla. 35.62 -98.07 11100301 8,060 Yes

R 1989-2007 No

127 07239500 North Canadian River near El Reno, Okla. 35.56 -97.96 11100301 9,820 Yes

U 1903-1907, 1939-

1947

No5

R 1949-2007 No

128 07241000 North Canadian River below Lake Overholser 

near OKC, Okla.

35.48 -97.66 11100301 8,320 Yes

R 1953-1987, 1989-

2007

No
Description of Study Area and Factors that Affect Streamflow in the Study Area 15

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

129 07241500 North Canadian River near Oklahoma City, 

Okla.

35.49 -97.43 11100302 8,460 Yes

R 1939-1960 No

130 07241520 North Canadian River at Britton Road at 

OKC, Okla.

35.57 -97.37 11100302 8,510 Yes

R 1989-2007 No

131 07241550 North Canadian River near Harrah, Okla. 35.50 -97.19 11100302 8,600 Yes

R 1969-2007 No

132 07242000 North Canadian River near Wetumka, Okla. 35.27 -96.21 11100302 9,390 Yes

R 1938-2007 No

133 07242350 Deep Fork near Arcadia, Okla. 35.65 -97.36 11100303 101 No UUrb 1970-1986 No

134 07242380 Deep Fork at Warwick, Okla. 35.68 -97.01 11100303 532 No

R 1988-2007 No

135 07243000 Dry Creek near Kendrick, Okla. 35.78 -96.85 11100303 68.4 Yes

U 1956-1994 Yes

136 07243500 Deep Fork near Beggs, Okla. 35.67 -96.07 11100303 2,000 Yes

U 1939-2007 Yes

137 07244000 Deep Fork near Dewar, Okla. 35.48 -95.88 11100303 2,300 Yes

U 1938-1950 Yes

138 07245000 Canadian River near Whitefield, Okla. 35.26 -95.24 11090204 37,900 No

U 1939-1963 No

R 1965-2007 No

139 07245500 Sallisaw Creek near Sallisaw, Okla. 35.46 -94.86 11110104 181 Yes

U 1943-1976 Yes

140 07247000 Poteau River at Cauthron, Ark. 34.92 -94.30 11110105 204 Yes

U 1939-2007 Yes

141 07247015 Poteau River at Loving, Okla. 34.88 -94.48 11110105 268 Yes

U 1992-2007 Yes

142 07247250 Black Fork below Big Creek near Page, Okla. 34.77 -94.51 11110105 94.3 Yes

U 1992-2007 Yes

143 07247500 Fourche Maline near Red Oak, Okla. 34.91 -95.16 11110105 120 Yes

U 1939-1991, 1992-

2007

Yes

144 07248500 Poteau River near Wister, Okla. 34.94 -94.72 11110105 994 Yes

U 1938-1948 Yes

R 1950-1984 No
16 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 145 07249400 James Fork near Hackett, Ark. 35.16 -94.41 11110105 147 Yes

U 1958-2007 Yes

146 07249413 Poteau River near Panama, Okla. 35.17 -94.65 11110105 1,770 Yes

R 1990, 1993-2007 No

147 07249500 Cove Creek near Lee Creek, Ark. 35.72 -94.41 11110104 34.8 Yes

U 1950-1970 Yes

148 07249985 Lee Creek near Short, Okla. 35.52 -94.46 11110104 434 Yes

U 1931-1936, 1950-

1991, 1993-2007

Yes

149 07250000 Lee Creek near Van Buren, Ark. 35.49 -94.45 11110104 438 Yes

U 1931-1936, 1951-

1993

Yes

150 07250550 Arkansas River at James W. Trimble L&D 

near Van Buren, Ark.

35.35 -94.30 11110104 128,800 No

U 1928-1963 No

R 1970-2007 No

151 07299200 Prairie Dog Town Fork Red River near 

Lakeview, Texas

34.57 -100.75 11120105 2,020 No

U 1963-1980 No

152 07299300 Little Red River near Turkey, Texas 34.54 -100.77 11120105 148 Yes

U 1968-1981 No5

153 07299540 Prairie Dog Town Fork Red River near Childress, Texas 34.57 -100.19 11120105 2,960 No

U 1965-2007 No

154 07299570 Red River near Quanah, Texas 34.41 -99.74 11130101 3,550 No

U 1960-1982 No

155 07299670 Groesbeck Creek at State Highway 6 near 

Quanah, Texas

34.35 -99.74 11130101 320 Yes

U 1962-2007 Yes

156 07299890 Lelia Lake Creek below Bell Creek near 

Hedley, Texas

34.94 -100.70 11120201 71.5 Yes

U 1998-2007 No5

157 07300500 Salt Fork Red River at Mangum, Okla. 34.86 -99.51 11120202 1,350 Yes

U 1938-2007 No5

158 07301110 Salt Fork Red River near Elmer, Okla. 34.48 -99.38 11120202 1,870 Yes

U 1980-2007 No5
Description of Study Area and Factors that Affect Streamflow in the Study Area 17

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

159 07301300 North Fork Red River near Shamrock, Texas 35.26 -100.24 11120302 817 Yes

U 1965-1991, 2000-

2007

No5

160 07301410 Sweetwater Creek near Kelton, Texas 35.47 -100.12 11120302 297 Yes

U 1962-2007 No5

161 07301420 Sweetwater Creek near Sweetwater, Okla. 35.42 -99.97 11120302 437 Yes

U 1986-2007 No5

162 07301500 North Fork Red River near Carter, Okla. 35.17 -99.51 11120302 2,100 Yes

U 1938-1962, 1964-

2007

Yes

163 07303000 North Fork Red River below Altus Dam near 

Lugert, Okla.

34.89 -99.31 11120302 2,120 Yes

R 1978-2007 No

164 07303400 Elm Fork of North Fork Red River near Carl, 

Okla.

35.01 -99.90 11120304 438 Yes

U 1960-1979, 1995-

2007

Yes

165 07303500 Elm Fork of North Fork Red River near 

Mangum, Okla.

34.93 -99.50 11120304 846 Yes

U 1905-1908, 1938-

1976

Yes

166 07304500 Elk Creek near Hobart, Okla. 34.91 -99.11 11120303 549 Yes

U 1905-1907, 1950-

1966

Yes

R 1967-1987 No

167 07305000 North Fork Red River near Headrick, Okla. 34.63 -99.10 11120303 3,850 Yes

R 1945-2007 No

168 07305500 West Otter Creek at Snyder Lake near Mountain Park, Okla. 34.73 -98.99 11120303 132 Yes

R 1976-2007 No

169 07307028 North Fork Red River near Tipton, Okla. 34.51 -99.21 11120303 4,290 Yes

R 1985-2007 No

170 07308500 Red River near Burkburnett, Texas 34.11 -98.53 11130102 14,600 No

U 1960-2007 No
18 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 171 07311000 East Cache Creek near Walters, Okla. 34.36 -98.28 11130202 694 Yes

U 1938-1960 No5

R 1962-1963, 1970-

2007

No

172 07311200 Blue Beaver Creek near Cache, Okla. 34.62 -98.56 11130203 24.7 Yes

R 1964-2003 No

173 07311500 Deep Red Creek near Randlett, Okla. 34.22 -98.45 11130203 604 Yes

U 1950-2007 Yes

174 07313000 Little Beaver Creek near Duncan, Okla. 34.49 -98.11 11130208 157 Yes

U 1949-1963 Yes

175 07313500 Beaver Creek near Waurika, Okla. 34.22 -98.05 11130208 564 Yes

U 1954-1976 No5

R 1978-1993 No

176 07315500 Red River near Terral, Okla. 33.88 -97.93 11130201 22,800 No

R 1945-1999, 2001-

2007

No

177 07315700 Mud Creek near Courtney, Okla. 34.00 -97.57 11130201 574 Yes

U 1961-2007 Yes

178 07316000 Red River near Gainesville, Texas 33.73 -97.16 11130210 24,800 No

R 1945-2007 No

179 07316500 Washita River near Cheyenne, Okla. 35.63 -99.67 11130301 763 Yes

U 1938-2007 No5

180 07319500 Sandstone Creek near Berlin, Okla. 35.51 -99.56 11130301 45.2 Yes

U 1953-1972 Yes

181 07323000 Sandstone Creek near Cheyenne, Okla. 35.55 -99.53 11130301 86.1 Yes

U 1952-1974 Yes

182 07324200 Washita River near Hammon, Okla. 35.66 -99.31 11130301 1,350 Yes

U 1970-1987, 1990-

2007

Yes

183 07324400 Washita River near Foss, Okla. 35.54 -99.17 11130302 1,550 Yes

R 1962-1987, 1990-

2007

No

184 07325000 Washita River near Clinton, Okla. 35.53 -98.97 11130302 1,950 Yes

U 1936-1960 Yes

R 1962-2007 No

185 07325500 Washita River at Carnegie, Okla. 35.12 -98.56 11130302 3,100 Yes

U 1938-2006 Yes
Description of Study Area and Factors that Affect Streamflow in the Study Area 19

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

186 07325800 Cobb Creek near Eakly, Okla. 35.29 -98.59 11130302 132 Yes

U 1969-2007 Yes

187 07326000 Cobb Creek near Fort Cobb, Okla. 35.14 -98.44 11130302 311 Yes

U 1940-1958 Yes

R 1960-2007 No

188 07326500 Washita River at Anadarko, Okla. 35.08 -98.24 11130302 3,660 Yes

R 1964-2007 No

189 07327000 Sugar Creek near Gracemont, Okla. 35.18 -98.26 11130302 206 Yes

U 1956-1974 Yes

190 073274406 Little Washita River above SCS Pond no. 26 

near Cyril, Okla.

34.91 -98.25 11130302 3.65 Yes

U 1996-2007 Yes

191 07327442 Little Washita River near Cyril, Okla. 34.89 -98.23 11130302 13.3 Yes

U 1993-2007 Yes

192 07327447 Little Washita River near Cement, Okla. 34.84 -98.12 11130302 62.3 Yes

U 1992-2007 Yes

193 07327490 Little Washita River near Ninnekah, Okla. 34.94 -97.95 11130302 208 Yes

U 1952-1986 Yes

194 07327550 Little Washita River east of Ninnekah, Okla. 34.96 -97.90 11130302 232 Yes

U 1992-2007 Yes

195 07328000 Washita River near Tabler, Okla. 34.97 -97.87 11130303 4,670 Yes

U 1940-1952 Yes

196 07328070 Winter Creek near Alex, Okla. 34.99 -97.76 11130303 33.1 Yes

U 1967-1986 Yes

197 07328100 Washita River at Alex, Okla. 34.93 -97.77 11130303 4,790 Yes

R 1965-2007 No

198 07328180 North Criner Creek near Criner, Okla. 34.97 -97.58 11130303 7.19 Yes

U 1989-2007 No5

199 07328500 Washita River near Pauls Valley, Okla. 34.75 -97.25 11130303 5,290 Yes

U 1938-1960 Yes

R 1962-2007 No

200 07329000 Rush Creek at Purdy, Okla. 34.70 -97.60 11130303 140 Yes

U 1940-1953, 1982-

1994

Yes

201 07329500 Rush Creek near Maysville, Okla. 34.74 -97.41 11130303 202 Yes

U 1955-1976 Yes
20 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 202 07329700 Wildhorse Creek near Hoover, Okla. 34.54 -97.25 11130303 604 Yes

R 1970-1995, 2001-

2007

No

203 07329852 Rock Creek at Sulphur, Okla. 34.50 -96.99 11130303 44.1 Yes

U 1990-2007 Yes

204 07329900 Rock Creek at Dougherty, Okla. 34.40 -97.04 11130303 137 Yes

U 1957-1966 Yes

205 07330500 Caddo Creek near Ardmore, Okla. 34.24 -97.11 11130303 296 Yes

U 1937-1950 Yes

206 07331000 Washita River near Dickson, Okla. 34.23 -96.98 11130303 7,160 Yes

U 1929-1960 Yes

R 1962-2007 No

207 07331600 Red River at Denison Dam near Denison, 

Texas

33.82 -96.56 11140101 33,800 No

U 1924-1943 No

R 1945-1989, 1998-

2007

No

208 07332400 Blue River at Milburn, Okla. 34.25 -96.55 11140102 203 Yes

U 1966-1987 Yes

209 07332500 Blue River near Blue, Okla. 34.00 -96.24 11140102 477 Yes

U 1937-2007 Yes

210 07332600 Bois D’Arc Creek near Randolph, Texas 33.48 -96.21 11140101 72.1 Yes

U 1963-1985 No5

211 07333500 Chickasaw Creek near Stringtown, Okla. 34.46 -96.03 11140103 32.6 Yes

U 1956-1968 Yes

212 07333800 McGee Creek near Stringtown, Okla. 34.44 -95.87 11140103 88.8 Yes

U 1956-1968 Yes

213 07334000 Muddy Boggy Creek near Farris, Okla. 34.27 -95.91 11140103 1,090 Yes

U 1938-1986 Yes

R 1988-2007 No

214 07335000 Clear Boggy Creek near Caney, Okla. 34.25 -96.21 11140104 713 Yes

U 1943-1989 Yes

215 07335300 Muddy Boggy Creek near Unger, Okla. 34.03 -95.75 11140103 2,260 Yes

R 1989-2007 No

216 07335400 Sanders Creek near Chicota, Texas 33.85 -95.54 11140101 175 Yes

R 1968-1986 No
Description of Study Area and Factors that Affect Streamflow in the Study Area 21

Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. —Continued[no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile]

Map

no.

USGS

station ID Station name

Location

HU 8

Drainage

area 

(square 

miles)1

Is Drainage

completely 

within

preprocessed 

area?2

Type of

record 

(U/R/I/Urb)

Period of record

Was 

period

used in

regression

analysis?3

Latitude 

(decimal 

degrees)

Longitude 

(decimal 

degrees)

217 07335500 Red River at Arthur City, Texas 33.88 -95.50 11140101 38,600 No

R 1945-2007 No

218 07335700 Kiamichi River near Big Cedar, Okla. 34.64 -94.61 11140105 39.6 Yes

U 1966-2007 Yes

219 07335790 Kiamichi River near Clayton, Okla. 34.57 -95.34 11140105 708 Yes

R 1984-2007 No

220 07336000 Tenmile Creek near Miller, Okla. 34.30 -95.74 11140105 68.3 Yes

U 1956-1970 Yes

221 07336200 Kiamichi River near Antlers, Okla. 34.25 -95.61 11140105 1,130 Yes

U 1973-1982 Yes

R 1984-2007 No

222 07336500 Kiamichi River near Belzoni, Okla. 34.20 -95.48 11140105 1,420 Yes

U 1926-1972 Yes

223 07336750 Little Pine Creek near Kanawha, Texas 33.84 -95.27 11140106 75.3 Yes

U 1969-1980 No5

224 07336800 Pecan Bayou near Clarksville, Texas 33.69 -94.99 11140106 98.9 Yes

U 1962-1978 No5

225 07336820 Red River near De Kalb, Texas 33.68 -94.69 11140106 41,400 No

R 1969-1999, 2003-

2007

No

226 07337500 Little River near Wright City, Okla. 34.07 -95.05 11140107 648 Yes

U 1930-1931, 1945-

1968

Yes

R 1970-1989 No

227 07337900 Glover River near Glover, Okla. 34.10 -94.90 11140107 320 Yes

U 1962-2007 Yes

228 07338500 Little River below Lukfata Creek near Idabel, 

Okla.

33.94 -94.76 11140107 1,230 Yes

U 1930-1968 Yes

R 1970-2007 No

229 07338750 Mountain Fork at Smithville, Okla. 34.46 -94.64 11140108 322 Yes

U 1992-2007 Yes

230 07339000 Mountain Fork near Eagletown, Okla. 34.04 -94.62 11140108 800 Yes

U 1924-1968 Yes

R 1969-2007 No
22 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 1. Description of streamflow-gaging stations in and near Oklahoma and periods of record where flow-duration and annual mean-flow statistics were calculated, and if selected periods of record were used in regression equations for estimating flow-duration and annual mean flow statistics at ungaged stream locations in Oklahoma. — Continued [no., number; Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Period of record, water years used to compute flow duration and annual mean flow statistics; HU 8, 8-digit hydrologic unit; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; L&D, lock and dam; SCS, soil conservation service; 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile] Map no. USGS station ID Station name Location HU 8 Drainage area (square miles)1 Is Drainage completely within preprocessed area?2 Type of record (U/R/I/Urb) Period of record Was period used in regression analysis?3 Latitude (decimal degrees) Longitude (decimal degrees) 231 07339500 Rolling Fork near DeQueen, Ark. 34.05 -94.41 11140109 183 Yes

U 1949-1973 Yes

232 07340300 Cossatot River near Vandervoort, Ark. 34.38 -94.24 11140109 89.1 Yes

U 1967-2007 Yes

233 07340500 Cossatot River near DeQueen, Ark. 34.05 -94.21 11140109 361 Yes

U 1938-1974 Yes

234 07341000 Saline River near Dierks, Ark. 34.10 -94.08 11140109 120 Yes

U 1939-1974 Yes

235 07341200 Saline River near Lockesburg, Ark. 33.96 -94.06 11140109 253 Yes

U 1963-1974 Yes

1Drainage area determined from ArcGIS software version 9.2 with National Hydrography Dataset 10-meter resolution elevation data. 2Basin characteristics could not be computed for gages where the drainage areas extend outside of the preprocessed hydrologic unit (S.J. Smith and R.A. Esralew, U.S. Geological Survey, written commun., 

2009). Streamflow statistics computed from gages in which basin characteristics could not be computed were not included in the regression analysis.

3 If a period of record for a streamflow-gaging station was used in the regression analysis, drainage-basin characteristics were computed and are presented in this report.4Flow duration and annual mean-flow statistics from gages in the Upper Beaver/North Canadian Basin and Upper Cimarron Basin (fig. 1) were not included in the final regression analysis because streams 

in these basins are substantially affected by irrigation withdrawals and diversions. Estimation of flow duration and annual mean flow statistics in this region using an unregulated period of record would not reflect current conditions and not be useful for application of these regressions for effective water-resources management. 

5This station was a significant outlier in the regression analysis and was not used to produce the regression equations listed in table 3, 4, or 5.6Gaines Creek near Krebs could not be used in regression analysis because the 10-85 channel slope, soil permeability, and percent forest canopy could not be accurately computed for the period of record of 

available streamflow data. The streamflow-gaging station was discontinued and is now located at the same site as Lake Eufaula.
Description of Study Area and Factors that Affect Streamflow in the Study Area 23

interest. The larger the contributing drainage area the greater 

the amount of water from precipitation is available as runoff 

to a stream. The entire drainage area upstream from a stream 

location can be considered “contributing” in most drainage 

basins in eastern, central, and most of western Oklahoma. Not 

all of the drainage area in a watershed in far western parts of 

the study area (including the Oklahoma and Texas Panhandles), contributes to streamflow because of playa lakes. Playa 

lakes are the largest noncontributing area in the study area. 

Playa lakes are dry lake beds that are formed as runoff collects 

in depressions and almost entirely infiltrates to groundwater or 

the water evaporates. Water that enters these lake beds does 

not directly reach the stream as runoff, therefore, areas that 

drain to playas can be considered noncontributing (Briere, 

2002). Areas upstream from playa lakes were not included in 

computation of contributing drainage area in this report.

Topography in the most northwestern part of the state is 

a flat upland surface originated on alluvial sands that evolves 

eastward to sandstone hills consisting of soft, flat-lying red 

Permian sandstones and shales. Areas in the northwest part of 

the state tend to be less topographically variable (smaller channel slope and lower drainage-basin hillslopes) than observed in 

the eastern part of the state, where the Ouachita Mountains in 

the southeast consist of high hills and ridges formed by tightly 

folded and faulted sandstones and shales, and the Ozark Plateau in the northeast, which form a deeply dissected plateau of 

limestones and cherts (Johnson and others, 1979). Elevation is 

variable across the state with the Great Plains in the Oklahoma 

Panhandle at more than 5,000 feet above the North American 

Vertical Datum of 1988 (NAVD 88). Elevations decrease 

eastward with the Arkansas and Red Rivers exiting the state of 

Oklahoma at less than 500 feet above NAVD 88 (fig. 2). 

Slope of the land surface or stream channel can affect the 

rate and amount of precipitation that is carried as runoff to a 

stream. Drainage basins that have lower average hillslopes 

and streams with lower slopes may result in a decreased 

magnitude of surface runoff from precipitation, potentially 

facilitating infiltration of runoff to groundwater through 

increased residence time of runoff on the land surface. Drainage basins that have greater hillslopes and channels that have 

steeper slopes also have the possibility to cause an increase in 

the magnitude of surface runoff during precipitation (Vieux, 

2001). Although soil permeability is highly variable throughout the state, generally soils in the western two-thirds of the 

state have greater permeability than soils in the north- and 

south-central parts of the state (fig. 3). The eastern and central 

parts of the state generally have soils of intermediate permeability as compared to soils in western and north- and southcentral Oklahoma. Soils with lower permeability may yield 

more runoff and less base flow compared to soils with higher 

permeability. Higher permeability in soils can result in more 

infiltration and a greater potential for contribution of groundwater during base flow (Thomas, 1966).

Forested landcover is highly variable across Oklahoma, 

with eastern Oklahoma having the greatest density of forested 

canopy (fig. 4). Because of increased evapotranspiration 

demands from vegetation during the growing season, forested areas can result in lower peak flow and a lower rate and 

smaller volume of surface runoff during precipitation events, 

especially during that time of year. Forested areas also typically have lower base flow per unit drainage area compared to 

unforested areas (Chang, 2006, p. 203-204). 

The magnitude and frequency of precipitation in a drainage basin during the course of a year can heavily affect the 

magnitude, duration, and frequency of elevated streamflow 

and base flow. Oklahoma has a diverse climate that is largely 

influenced by the geographic location of the state on the 

leeward side of the Rocky Mountains. Annual precipitation 

increases from 16 inches in the far west to 56 inches in the 

southeast. Average annual precipitation follows an east-west 

gradient in Oklahoma (fig. 5). Precipitation falls in the form 

of widespread rains and locally intense thunderstorms and 

generally is greatest in late spring and early autumn (Eddy, 

1982). Convective spring and summer storms also can cause 

substantial runoff. Precipitation can be highly variable during 

summer and early autumn because of the influence of periodic 

tropical disturbances from the Gulf of Mexico (Arndt, 2003). 

Absence of autumn-season rains may cause a prolonged period 

of less than average streamflow (Tortorelli, 1991).

Anthropogenic Activities 

Many streams throughout the study area are affected by 

anthropogenic activities that can alter the flow regime and 

affect streamflow statistics. Anthropogenic activities that may 

affect flow-duration and annual mean-flow statistics include, 

but are not limited to, regulation, irrigation withdrawals, and 

urban change.

The effect of regulation on flow downstream from 

dams is variable and depends on water uses for the reservoir. 

Managed releases of water downstream from reservoirs may 

influence the shape of the hydrograph and can affect the flow 

regime. Surface-water withdrawals, especially from large 

water-supply reservoirs, may reduce streamflow magnitude 

downstream depending on how much is withdrawn (Collier 

and others, 2000). 

Oklahoma has more than 2,250 floodwater retarding 

(FWR) structures, mostly built by the Soil Conservation 

Service, currently the Natural Resources Conservation Service 

(NRCS), from the period of 1957 to present (S.J. Smith and 

R.A. Esralew, U.S. Geological Survey, written commun., 

2009). Construction of FWR structures can reduce the magnitude of peaks and prolong the return to base flow during 

runoff. However, these structures may not have a strong effect 

on flow exceedance probabilities even though the structures 

hold flow during runoff, because the total amount of discharge 

downstream from the structure is unchanged during the course 

of streamflow events (Tortorelli and Bergman, 1985). This 

change in streamflow timing during runoff is not likely to have 
24 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Figure 2. Land-surface elevation in Oklahoma and parts of adjacent states.

Albers Equal-Area Conic ProjectionNorth American Datum 1983

KANSAS

TEXAS

ARKANSAS

MISSOURI COLORADO

NEW

MEXICO

100°

36°

97°

94° 103°

34°

0 5025 MILES

0 50 KILOMETERS

EXPLANATION

8,710230

Elevation, in feet above North American Vertical Datum of 1988

Study area boundary

State boundary

Stream

Ouachita

Ozark Plateau

MountainsPhysiographic Province Boundary
Description of Study Area and Factors that Affect Streamflow in the Study Area 25 Figure 3. Areas of equal average soil permeability in Oklahoma and parts of adjacent states relative to three regions used in regression analysis, and three regions used for developing regression equations. Albers Equal-Area Conic Projection North American Datum 1983 Soil permeability from Natural Resources Conservation Service, 2006

KANSAS

TEXAS

A R K A NS A S

MISSOURI COLORADO

NEW

MEXICO

100° 

36° 

97° 

94° 103° 

34° 

0 5025 MILES0 50 KILOMETERS

1

2b

3

2a Data Not Used

State boundaryStream

Soil permeability, in inches per hour

Regression region boundary

13.000.05

EXPLANATION
26 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Figure 4. Percent forest canopy in Oklahoma and parts of adjacent states relative to three regions used in regression analysis, and three regions used for developing regression equations.

Albers Equal-Area Conic ProjectionNorth American Datum 1983Data from U.S. Geological Survey 2001  National Landcover Database

KANSAS

TEXAS

A R K A NS A S

MISSOURI COLORADO

NEW

MEXICO

100° 

36° 

97° 

94° 103° 

34° 

0 5025 MILES0 50 KILOMETERS

1

2b

3

2a Data Not Used

EXPLANATION

State boundaryStream1000

Forest canopy, in percent

Regression region boundary
Description of Study Area and Factors that Affect Streamflow in the Study Area 27 Figure 5. Mean-annual precipitation in Oklahoma and parts of adjacent states.

KANSAS

TEXAS

ARKANSAS

MISSOURI COLORADO

NEW

MEXICO

100°

36°

97°

94° 103°

34°

Albers Equal-Area Conic Projection

North American Datum 1983

Data from Parameter-elevation

Regressions on IndependentSlopes Model (PRISM) Dataset (PRISM

Climate Group, 2008)

0 5025 MILES

0 50 KILOMETERS

EXPLANATION

State boundary

Stream

71.6914.35

Mean-annual precipitation (1971-2000), in inches

Study area boundary
28 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

a strong effect on annual mean-flow or median flow-duration 

statistics. These structures may, however, have an effect on 

low flow because of an increased potential for infiltration 

because runoff is held behind the retention dam (R.L. Tortorelli, oral and written commun., August 2008). 

Irrigation water uses vary across Oklahoma and are more 

pronounced in the western part of the state (Tortorelli, 2009). 

Irrigation water use, whether water is derived from groundwater or surface-water sources, can have a substantial effect 

on the variability of low flow because of nearby withdrawals and irrigation returns. Streamflow in the Upper Beaver/

North Canadian Basin and Upper Cimarron Basin (fig. 1), are 

substantially affected by irrigation withdrawals (Wahl and Tortorelli, 1997 and R.L. Tortorelli and D. Boyle, oral and written 

commun., June 2008). 

Drainage basins affected by urban change can have a 

substantial effect on the flow regime. Construction of roads 

and buildings involves removing vegetation, soil, and depressions from the land surface. The permeable soil is replaced by 

impermeable surfaces such as roads, roofs, parking lots, and 

sidewalks that store little water, reduce infiltration of water 

into the ground, and accelerate runoff to ditches and streams 

(Konrad, 2003). 

Calculation of Flow-Duration and 

Annual Mean-flow Statistics at Gaging 

Stations

Streamflow Data Used for Calculation of 

Statistics

Daily mean discharge data collected from 235 continuous 

streamflow-gaging stations were used to calculate flow-duration and annual mean-streamflow statistics. Daily mean flows 

for USGS gaging stations in Oklahoma and adjacent states are 

available on the World Wide Web (URL http://waterdata.usgs.

gov/ok/nwis/ and http://waterdata.usgs.gov/us/nwis ). Daily 

mean flow is the mean of instantaneous discharges for a day 

(Buchanan and Somers, 1976). Instantaneous discharge data 

from gaging stations are collected as stage data, and instantaneous discharge is estimated from the rating curve, which is a 

relation between stage and discharge at a stream cross section 

(Rantz and others, 1982). Each gaging station selected for 

computation of flow-duration and annual mean-flow statistics had at least 10 complete water years of daily streamflow 

record as of water year 20071

. Gaps in the continuous record 

were accepted as long as the total record equaled or exceeded 

10 complete water years of record.

1

 A water year is the 12-month period October 1 through September 30 and 

is designated by the calendar year in which it ends.

Data from gaging stations were not used in the regression analysis if the (1) streamflow is regulated by water-supply 

reservoirs, (2) withdrawals for irrigation and other water 

use substantially affect discharge, or (3) streamflow is likely 

affected by urban change. However, flow-duration and annual 

mean-streamflow statistics for periods of record affected by 

these circumstances were still calculated and are presented 

in this report. These statistics also can be used to estimate 

flow statistics at ungaged locations by using the drainage-area 

ratio method if the ungaged location is near a gaging station 

affected by these circumstances (see section titled “Methods of 

Estimating Flow-Duration and Annual Mean-Flow Statistics 

at Ungaged Stream Locations”). Separate periods of record 

for these sites were defined as the period when the effects of 

regulation, regional irrigation, or urban change were suspected 

to substantially affect streamflow at the gaging station. 

A gaging station was considered substantially affected 

by regulation if 20 percent or more of the drainage basin 

upstream from the gage was regulated by major water-supply 

reservoirs (Tortorelli, 2002; Lewis and Esralew, 2009). For 

larger water-supply reservoirs, the year of construction marked 

the end of the unregulated period of record and beginning of 

the regulated period of record for a gaging station. However, 

streamflow in drainage-basins affected by FWR structures was 

not considered regulated for this study. Observations in this 

study indicated that most gaging stations affected by FWR 

structures had no substantial difference in either flow-duration 

or annual mean-flow statistics between the period before construction and the period after construction. In addition, had 

periods affected by FWR structures been included as regulated 

periods, a large percentage of data from many gaging stations 

would have been eliminated. 

Periods of record for gaging stations that were substantially affected by withdrawals for irrigation and other 

water use were determined by hydrographer remarks (R.L. 

Tortorelli, D. Boyle, oral and written commun., June–July 

2008) and analysis notes from previous publications (Wahl 

and Tortorelli, 1997; Smith and Wahl, 2003; Tortorelli, 2002; 

Tortorelli and others, 2005; Lewis and Esralew, 2009). Visual 

inspection of the annual hydrographs determined the irrigated 

period of record for sites with downward trends for peak 

flow and annual mean flow as a result of irrigation activities 

(Tortorelli and others, 2005). The year that annual peak flows 

substantially dropped was the starting year of the irrigation 

period (table 1). 

Hydrographer and analysis notes from previous publications revealed that many gaging stations may be affected by 

minor anthropogenic activities such as localized irrigation, 

sewage effluent, or other minor diversions. For this study, 

mention of these activities in historical notes did not result in a 

split period of record because the period when these activities 

started could not be quantified by hydrograph inspection. 

Periods of record affected by urbanization also were identified. Gaging stations with drainage-basins that had an impervious surface of 10 percent or greater from the USGS 2001 
Calculation of Flow-Duration and Annual Mean-flow Statistics at Gaging Stations 29

National Land Cover Dataset (NLCD) (http:// landcover.usgs.

gov/ natllandcover.php, accessed July 2008) were considered 

to be affected by urban change (Tortorelli, 2002; Lewis and 

Esralew, 2009). Analysis of historic impervious surface prior 

to 2001 was not performed for this study; therefore, if this 

threshold was met by using the 2001 NLCD, the entire period 

of record was assumed to be affected by urban change. 

Each separate period of record at a gaging station 

(unregulated, irrigated, regulated, or urban) required a 

minimum of 10 complete water years in order for statistics 

to be calculated for that period. For this report, if a period of 

record was not substantially affected by regulation, irrigation, 

or urban change, the site was referred to as “unregulated”. 

Periods of record that may be affected by minor anthropogenic 

activities are still referred to as “unregulated” in this report. If 

a period was substantially affected by irrigation activity but 

was not affected by regulation, that period is referred to as 

“unregulated irrigated” . If a period was affected by regulation and irrigation, or regulation and urban change, that period 

is referred to as “regulated irrigated” or “regulated urban,” 

respectively. Table 1 includes a list of gaging stations where 

flow-duration and annual mean-flow statistics were calculated, 

the period of record for which these statistics were calculated, 

and the kind of period of record (unregulated, regulated, irrigated, or urban). Table 1 also indicates whether the streamflow data from that period of record was included in regression analysis (described in the section titled “Selection of Data 

for Use in Regression Analysis”). Flow-duration and annual 

mean-flow statistics were computed for 235 gaging stations. 

Flow statistics for gaging stations with more than one kind of 

period of record were computed for 45 gaging stations. One 

hundred and seventy-seven gaging stations had flow statistics calculated for an unregulated period, 89 gaging stations 

had flow statistics computed for a regulated period of record 

(including 5 gaging stations that also were affected by irrigation for the same period), 6 gaging stations had flow statistics 

computed for an unregulated irrigated period, and 8 gaging 

stations had flow statistics computed for an unregulated urban 

period. 

Calculation of Statistics

The USGS has established standard methods for estimating flow-duration and annual mean-flow statistics for gaging 

stations (Searcy, 1959). The computer software programs 

IOWDM, ANNIE, and SWSTAT were used to format input 

data and calculate flow-duration and annual mean-flow 

statistics (Lumb and others, 1990; Flynn and others, 1995). 

These programs are available on the World Wide Web (URL 

http://water.usgs.gov/software/surface_water.html). Daily 

mean flows for all complete water years of record for periods 

identified in table 1 were used to determine flow-duration 

curves that were used to derive flow-duration statistics. Flowduration curves (fig. 6) are graphical representations of the 

percentage of the time that streamflow for a given time step 

(for example, a daily time step) is equaled or exceeded during 

a specified period. 

Flow-duration statistics are points along a flow-duration 

curve and represent the discharge that is exceeded for a given 

percentage of time. For this report, flow-duration statistics 

are referred to as “D” followed by the exceedance probability. 

For example, the 95-percent flow-duration statistic or D95 represents the streamflow that is equaled or exceeded 95 percent 

of the time; whereas, the 50-percent flow-duration statistic 

(median, or D50) is the streamflow that is equaled or exceeded 

50 percent of the time. 

Flow-duration statistics reflect only the period for which 

these statistics are calculated and flow-duration statistics that 

are calculated or estimated by using past record should not be 

considered a forecast of future streamflow (Leopold, 1959). 

The period of record used for flow-duration curve calculation 

can be for the complete period of record, or daily flows during 

a specified period in the period of record, such as a month or 

group of months. For example, flow-duration statistics can be 

calculated by using only those daily flows during the month 

of October, when at least 10 complete water years of data of 

daily flow data are available. 

Flow-duration curves were constructed for daily flow 

data in SWSTAT for annual (all daily flow during the period 

of record), seasonal (daily flow from June 1st through October 31st, which is referred to as the summer-autumn period, 

and daily flow from November 1st through May 31st, which 

is referred to as the winter-spring period), and monthly time 

periods (daily flow data during each of 12 months). Summerautumn and winter-spring periods correspond to the regulatory 

seasons used by OWRB for water-supply permits. The procedure in SWSTAT used to compute flow-duration statistics is 

similar to that in Lewis and Esralew (2009). 

Flow-duration curves for D20, D50, D80, D90, and D95 were 

used to compute the one annual, two seasonal, and twelve 

monthly time periods (a total of 75 flow-duration statistics). 

Flow-duration statistics for individual gaging stations were 

computed separately for each kind of period of record (table 

1). Flow-duration and annual mean-flow statistics for each 

station are presented in tables 2 through 6 (back of report). 

Abbreviations of flow statistics for tables in this report 

follow the naming conventions used by USGS StreamStats 

(http://water.usgs.gov/osw/streamstats/StatisticsDefinitions.

html accessed November 2009). Summer-autumn and winterspring flow-duration statistics are referred to as the flow-duration statistic followed by SUM and WSP, respectively. For 

example, the D20 for the summer-autumn period is referred to 

as D20SUM and the D95 for the winter-spring period is referred 

to as D95WSP. Monthly flow-duration statistics are referred to 

by the first three letters of the month followed by the flowduration statistic. For example, OCTD20 refers to the D20 for 

daily flows during October, and SEPD95 refers to the D95 for 

daily flows during September.
30 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Methods of Estimating Flow-Duration 

and Annual Mean-Flow Statistics at 

Ungaged Stream Locations

Flow-duration and annual mean-flow statistics can 

be estimated at ungaged stream sites by using a drainagearea ratio relation and a regional regression equation. If an 

ungaged stream location is near a gaging station on the same 

stream reach, the drainage-area ratio method is the preferred 

method for estimating flow statistics. As an alternative, to 

estimate streamflow statistics at ungaged streams not near a 

gaging station on the same reach, a regression equation relating the streamflow statistic for gaging stations in a defined 

region to one or more drainage-basin characteristics can be 

created.

Drainage-Area Ratio Method

The drainage-area ratio method is based on the assumption that the unit area runoff of the ungaged drainage-basin is 

the same as that for the gaged site (and that no substantially 

large tributaries are between the location of the gaged and 

ungaged site). Streamflow statistics are computed for the 

gaged location, then the statistics are divided by the drainage 

area to determine streamflow per unit area at the gaged location. The equation used in this method (Ries and Friesz, 2000; 

Perry and others, 2004; Risley and others, 2008) follows:

Qs

 = [DAs / DAg] * Qg (1)

where

Qs is the low-flow statistic of the ungaged 

 site, in cubic feet per second;

DAs is the drainage area of the ungaged site, 

 in square miles;

DAg is the drainage area of the gaging station

 (upstream or downstream) in square

 miles; and 

Qg is the low-flow statistic of the gaging

 station (upstream or downstream) in

 cubic feet per second.

The drainage-area ratio method can be used by weighting the average ratios of drainage areas at the gaging stations 

to the ungaged site drainage area if the ungaged location is 

between two gaging stations by the following equation:

Qs = [Qgu (DAgd – DAs

) + Qdu (DAs – DAgu)] / (DAgd – DAgu) (2)

where

Qgu is the flow statistic at the upstream gaging

 station, in cubic feet per second;

Qdu is the flow statistic at the downstream gaging

 station, in cubic feet per second;

Figure 6. Example of a flow-duration curve for Baron Fork at Eldon, Oklahoma (U.S. 

Geological Survey station identifier 07197000, map number 99 on figure 1), by using 

daily streamflow data for the entire period of record, 1949–2007.

Exceedance probability (in percent)

)dnocesrepteefcibucni(wolfmaertsnaemyliaD

Used to develop regression equations to

estimate flow-duration statistics at ungaged

stream locations

1

10

100

1,000

10,000

0 20 50 80 90 95
Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics at Unregulated Ungaged Stream Locations in Oklahoma 31

DAgu is the drainage area of the upstream gaging

 station, in square miles;

DAgd is the drainage area of the downstream

 gaging station, in square miles.

The method generally is reliable if the drainage-area 

ratio of the two sites is between 0.5 and 1.5 (Risley and others, 2008). Where an ungaged location meets this criteria for 

gaged streams with known effects from regulation, irrigation, 

and urban change, this method can be used to estimate flow 

statistics as long as the record from the gaging station used to 

compute the statistic also is affected by the same condition.

Regression Equation Method

Multiple-linear regression analysis (referred to as regression analysis in this report) is used to develop equations 

for estimating a variety of streamflow statistics at ungaged 

stream locations. An equation relating the streamflow statistic 

(dependent variable) to one or more drainage-basin characteristics (the independent variables) can be used to estimate the 

streamflow statistic for ungaged stream locations.

The multiple-linear regression equation takes the general 

form:

Yi = bo + b1

 X1 + b2X2 + ... + bnXn + ei (3)

where

Yi is the value of the dependent variable, or 

streamflow statistic, for station 1; 

bo to bn are the n+1 regression-model 

coefficients;

X1 to Xn are the n independent variables, or 

series of drainage-basin characteristics 

used in the regression equation; and 

ei is the residual error (difference between the 

observed and estimated values of the 

dependent variables). 

A least-squares method can be used in regression analysis 

to estimate the regression equation coefficients. This method 

in this report is referred to as Ordinary Least-Squares (OLS) 

regression analysis. The coefficients are determined after 

minimizing the sum of the squared differences, or errors, of 

the measured and estimated data points. In OLS regression, 

each data observation used in the analysis is assumed to provide equal information to the equation. All data observations 

are then given an equal weight in determining the equation 

coefficients through minimizing the sum of the squared errors.

For an optimal regression developed by using OLS procedures, four basic assumptions are needed: (1) the regression 

equation adequately describes the relation between the dependent and independent variables, (2) the variance of the residual 

error, ei

, is constant and independent of the values of X1 to Xn, 

(3) the residual errors, ei

, are normally distributed, and (4) the 

ei

 are independent of each other (Helsel and Hirsch, 1992).

Streamflow statistics and drainage-basin characteristics 

used in regression equations that estimate hydrologic conditions are typically log-normally distributed. Transformation of 

the variables to logarithms is usually necessary to satisfy the 

third assumption. All streamflow and drainage-basin characteristic data for use in the multiple-regression analysis can be 

transformed to base-10 logarithms to obtain a linear regression 

equation and to avoid inconsistent variance about the regression line. Transformation of variables results in the following 

equation:

log Yi = bo + b1

1og X1 + b2log X2 + ... + bn log Xn + ei (4)

that can be retransformed to the original units by using an 

anti-logarithm:

Yi

 = 10 bo *( X1

b1)*( X2

b2)...( Xnbn)*10 ei (5)

The application of methods used to develop regression 

equations to estimate flow-duration and annual mean-flow 

statistics for ungaged stream locations are discussed in more 

detail in section, “Methods Used to Develop Regression 

Equations”

Development of Regression Equations 

to Estimate Flow-Duration and Annual 

Mean-Flow Statistics at Unregulated 

Ungaged Stream Locations in 

Oklahoma

The methods used to develop regression equations to estimate flow-duration and annual mean-flow statistics throughout 

Oklahoma involved (1) selection of gaging stations and drainage-basin characteristics for use in the regression analysis, (2) 

delineation of regression regions in the study area to increase 

regression accuracy, and (3) regression analysis including 

alternative techniques to handle flow-duration datasets where 

zero flow exceedances were observed. 

Selection of Data for Use in Regression Analysis

Data selected for regression analysis included flowduration and annual mean-flow statistics, and drainage-basin 

characteristics, from selected gaging stations in the study 

area. Gaging stations selected for regression analysis needed 

to have streamflow data from a period of record not affected 

Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics
32 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

by anthropogenic activities and drainage-basin characteristic 

data. Drainage-basin characteristic data selected for regression analysis included those characteristics that had a hydrologic and physical basis for use as independent variables for 

estimating flow statistics and could be easily applied to the 

StreamStats web application.

Selection of Sites and Periods of Record 

Streams selected for regression analysis included only 

those streams where the drainage area was completely in 

8-digit hydrologic unit (HU) boundaries that are in Oklahoma 

or adjacent to the Oklahoma state border (fig. 1). These criteria were required because drainage-basin characteristic data 

were not available for gaging stations that extended outside of 

this area (table 1). Of 235 gaging stations where flow statistics were calculated, 41 gaging stations had drainage areas that 

extended outside of the study area boundaries.

Flow statistics from gaging stations with drainage areas 

not completely in the study area, and flow statistics from 

periods of record that were affected by regulation, irrigation, 

or urban change, were not used in regression analysis. The 

effects of these circumstances on the hydrology of the area are 

highly variable and cannot be appropriately characterized by a 

regional regression approach. The earlier unregulated period 

was used in the regression for some gaging stations where 

statistics were calculated for more than one period because 

effects from regulation, irrigation, or urban change happened 

at a later point in the full period of record. The later period 

was not included in the analysis (table 1). 

For this study, periods of record that may be affected by 

minor anthropogenic activities such as localized irrigation, 

sewage effluent, and small diversions were still included in 

the regression analysis. Removal of streamflow data from the 

regression analysis from periods of record that may be affected 

by minor anthropogenic activities would have resulted in a 

large amount of data being removed from the analysis. 

Streamflow in the Upper Beaver/North Canadian Basin 

and Upper Cimarron Basin (fig. 1) are substantially affected 

by irrigation withdrawals (Wahl and Tortorelli, 1997 and 

R.L. Tortorelli and D. Boyle, oral and written commun., June 

2008). Neither flow-duration or annual mean-flow statistics 

calculated for gaging stations in the Upper Beaver/North 

Canadian and Upper Cimarron Basins were included in the 

final regression analysis even if statistics from an unregulated 

period of record prior to known effects from irrigation were 

available (table 1). Estimated statistics in this region by using 

an unregulated period of record for these gaging stations 

would not reflect current circumstances and would not be 

useful for application of these regressions for effective waterresources management. 

Of 194 gaging stations with drainage-basins completely 

in the study area, 137 gaging stations were initially used in 

the regression analysis (fig. 1). Twelve gaging stations in the 

Upper Cimarron and Upper Beaver/North Canadian Basins 

were not used in the regression analysis (table 1). 

Selection and Computation of Drainage-Basin 

Characteristics

Physical and climatic characteristics of the drainagebasins upstream from the gaging stations were used as 

independent variables in the regression equations to predict 

streamflow statistics at ungaged sites. Using Geographic 

Information System (GIS) techniques, 23 drainage-basin characteristics were computed for the 137 gaging stations initially 

used in the regression analysis. Drainage-basin characteristics 

were selected only for the regression analysis if a feasible way 

was available to automatically compute them in the StreamStats web application (Alan H. Rhea, Peter A. Steeves, and 

Kernell G. Ries, U.S. Geological Survey, oral and written 

communication, January 2007).

Drainage-basin characteristics considered for use in 

the regression equations include contributing drainage area; 

10-85 channel slope; mean drainage-basin hillslope; mean 

drainage-basin elevation and stream outlet elevation (at the 

gage); percentage of drainage-basin covered by forest canopy; 

mean drainage-basin soil permeability; mean-annual precipitation over the drainage basin; and mean annual, seasonal, and 

monthly precipitation at the gaging station. Definitions of 

drainage-basin characteristics are listed in table 7. Abbreviations for this report for drainage-basin characteristics follow 

the naming conventions used by USGS StreamStats (http://

water.usgs.gov/osw/streamstats/bcdefinitions1.html accessed 

November 2009).

The final selection of 13 drainage-basin characteristics 

that were used in the regression equations are listed in table 

8 (back of report). The computations of drainage-basin 

characteristics were made by using ArcGIS software version 

9.2 (Environmental Systems Research Institute, 2007). Data 

sources for the digital datasets used to compute drainage-basin 

characteristics included the National Hydrography Dataset 

(NHD) (http://nhd.usgs.gov, accessed July 2008), Parameterelevation Regressions on Independent Slopes Model (PRISM) 

(PRISM Climate Group, 2008), NRCS State Soil Geographic 

(STATSGO) dataset (Natural Resources Conservation Service, 2006), NRCS Watershed Boundary Dataset (WBD) 

(http://www.ncgc.nrcs.usda.gov/products/datasets/watershed/, 

accessed June 2006), and USGS 2001 National Land Cover 

Dataset (NLCD) (U.S. Geological Survey, 2009).

Attempts were made to ensure that the selected drainagebasin characteristics had a physical and hydrologic basis to 

be used as independent variables to estimate flow statistics. 

However, no direct hydrologic explanation is indicated for 

inclusion of mean drainage-basin elevation or stream outlet 

elevation in the regression equations aside from the possibility 

that streams that are closer to one another may be similar in 

elevation. These parameters were included only as independent variables in the final regression equations if the standard 

error of the estimate was reduced by 20 percent or more 

compared to regression equations that did not include either of 

these parameters.
Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics at Unregulated Ungaged Stream Locations in Oklahoma Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics 33

Table 7. Description of drainage-basin characteristics used in regression analysis in order to estimate flow-duration and annual 

mean-flow statistics in Oklahoma. —Continued

[NED, National Elevation Dataset; NHD, National Hydrography Dataset; WBD, Watershed Boundary Dataset; NAVD 1988, North American Vertical Datum 

of 1988; NLCD, National Land Cover Dataset; STATSGO, State Soil Geographic Database; PRISM, Parameter-Elevation Regressions on Independent Slopes 

Model

Basin characteristic 

(identifier)

Description Data source

Contributing drainage area 

(CONTDA)

Contributing drainage basin 

area, in square miles

NED 10-meter resolution elevation data (http://seamless.usgs.gov/

index.php), NHD (http://nhdgeo.usgs.gov/viewer.htm, accessed July 

2006) and WBD (source: http://www.ncgc.nrcs.usda.gov/products/

datasets/watershed/, accessed July 2006)

10-85 Channel Slope 

(CSL10_85fm)

Channel slope between 

points 10 and 85 percent 

of the stream length starting from the gage location 

and along the longest flow 

path, in feet per mile

NED 10-meter resolution elevation data (http://seamless.usgs.gov/

index.php), and NHD (http://nhdgeo.usgs.gov/viewer.htm, accessed 

July 2006) 

Mean Hillslope 

(BSLDEM10M)

Mean drainage-basin hillslope, in percent

NED 10-meter resolution elevation data (http://seamless.usgs.gov/

index.php)

Mean elevation 

(ELEV)

Mean drainage-basin elevation, in feet above NAVD 

1988

NED 10-meter resolution elevation data (http://seamless.usgs.gov/

index.php), and NHD (http://nhdgeo.usgs.gov/viewer.htm, accessed 

July 2006) 

Stream Outlet Elevation 

(OUTLETELEV)

Elevation at the gage, in feet 

above datum

NED 10-meter resolution elevation data (http://seamless.usgs.gov/

index.php), and NHD (http://nhdgeo. usgs.gov/viewer.htm, accessed 

July 2006) 

Percent Forest Canopy 

(CANOPY_PCT)

Percent drainage-basin 

surface area containing 

forest cover

30-meter resolution data layers from the NLCD (2001); forest categories included: deciduous, evergreen, and mixed. Source: http:// 

landcover.usgs.gov/natllandcover.php, accessed July 2008.

Soil permeability 

(SOILPERM)

Mean drainge-basin soil 

permeability in inches per 

hour

1:250,000 STATSGO map. Source: http://www.soils.usda.gov/survey/

geography/statsgo/, accessed July 2008.

Mean annual precipitation 

(PRECIPOUT)

Mean annual precipitation 

(1971-2000) at the gage, 

in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean annual precipitation 

(PRECIP)

Mean annual precipitation 

(1971-2000) over the 

drainage-basin area, in 

inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean summer-autumn precipitation

(PREG_06_10)

Mean summer-autumn precipitation (June through 

October, 1971-2000) at 

the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean winter-spring precipitation

(PREG_11_05)

Mean winter-spring precipitation (November through 

May, 1971-2000) at the 

gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean January precipitation 

(JANAVPRE)

Mean February precipitation 

at the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean February precipitation 

(FEBAVPRE)

Mean February precipitation 

at the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean March precipitation 

(MARAVPRE)

Mean March precipitation at 

the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008
34 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Table 7. Description of drainage-basin characteristics used in regression analysis in order to estimate flow-duration and annual 

mean-flow statistics in Oklahoma. —Continued

[NED, National Elevation Dataset; NHD, National Hydrography Dataset; WBD, Watershed Boundary Dataset; NAVD 1988, North American Vertical Datum 

of 1988; NLCD, National Land Cover Dataset; STATSGO, State Soil Geographic Database; PRISM, Parameter-Elevation Regressions on Independent Slopes 

Model

Basin characteristic 

(identifier)

Description Data source

Mean April precipitation 

(APRAVPRE)

Mean April precipitation at 

the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean May precipitation 

(MAYAVPRE)

Mean May precipitation at 

the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean June precipitation 

(JUNAVPRE)

Mean June precipitation at 

the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean July precipitation 

(JULAVPRE)

Mean July precipitation at 

the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean August precipitation 

(AUGAVPRE)

Mean August precipitation 

at the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean September precipitation 

(SEPAVPRE)

Mean September precipitation at the gage, in inches800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean October precipitation 

(OCTAVPRE)

Mean October precipitation 

at the gage, in inches

800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean November precipitation 

(NOVAVPRE)

Mean November precipitation at the gage, in inches800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008

Mean December precipitation 

(DECAVPRE)

Mean December precipitation at the gage, in inches800-meter resolution data layer created from PRISM dataset. Source: 

http://www.prism.oregonstate.edu/, accessed July 2008
Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics at Unregulated Ungaged Stream Locations in Oklahoma 35

Determination of Regression Regions

Attempts are made to define regions in regional streamflow analyses that are hydrologically similar in terms of physical characteristics being studied (Haan, 1977). The study area 

includes all gaging stations in which the drainage-basin area 

is completely in 8-digit HU boundaries that are in Oklahoma 

or adjacent to the Oklahoma state border. However, Oklahoma has diverse physical and climatic characteristics that 

can affect streamflow, and this regional variability can pose 

challenges to selecting independent variables for use in regression equations. Preliminary analysis indicated that grouping 

gaging stations in the study area into regions with similar 

physical drainage-basin characteristics increased the accuracy 

of regression estimates as opposed to originating one set of 

regression equations for the entire study area (Esralew, 2009). 

Use of regression regions in this preliminary analysis helped 

to substantially increase regression estimates of flow-duration 

statistics for median flow and lower flow exceedances (D50, 

D80, D90, and D95).

A k-means cluster analysis was performed to group gaging stations with similar physical drainage-basin characteristics. The cluster analysis was performed in S-Plus (Insightful 

Corporation, 2007) by using selected drainage-basin characteristics obtained for 137 gaging stations initially used in the 

regression analysis. Variables used in the cluster analysis were 

derived from continuous spatial drainage-basin characteristics, 

and included forested canopy, soil permeability, and annual 

mean precipitation to facilitate grouping of gaging stations 

into regions with similar physical drainage-basin characteristics. Drainage-basin characteristics that were related to 

drainage size or were specific to gage location (such as channel slope, mean drainage-basin hillslope, or mean and outlet 

elevation) were not included in the cluster analysis.

The results of the cluster analysis indicated that gaging stations could be divided into three groups that could be 

separated into distinct spatial regions. On the basis of the 

cluster analysis, spatial regions were defined by using manual 

delineation. Delineated boundaries were determined on the 

basis of five factors: (1) grouping gaging stations with similar 

drainage-basin characteristics as a result of the cluster analysis; (2) major watershed boundaries; (3) geographic features, 

such as mountains, geologically heterogeneous areas, or other 

distinct geologic divides; (4) U.S. Environmental Protection 

Agency (USEPA) ecoregion boundaries (Woods and others, 

2005); and (5) general knowledge of the area. Ecoregions, 

which summarize areas with similar climatic and geologic 

characteristics, were used to guide manual delineation of 

region boundaries (fig. 7). Where ecoregion boundaries do 

not line up with region boundaries, other hydrologic, climatic, or geologic characteristics were used to guide manual 

delineation. Hydrologic boundaries, such as the 8-digit HU 

and smaller sub-catchments, were used, where possible, to 

delineate regions. This procedure was done to avoid arbitrary 

boundaries that cut across natural drainages. 

Gaging stations in the Upper Beaver/North Canadian 

and Upper Cimarron Basins were not included in the cluster 

analysis. These drainage basins were not included in the final 

region delineation because flow-duration and annual meanflow statistics computed for all periods of record for the gaging stations in this region were not used in regression analysis 

(see section titled “Selection of Data for Use in Regression 

Analysis”).

Drainage basins for the gaging stations in Region 1, 

the western region, had little to no forested area and areas of 

higher average soil permeability than Regions 2 and 3 (figs. 

3 and 4). Region 1, which is in western Oklahoma excluding 

the Upper Beaver/North Canadian Basin and Upper Cimarron 

Basin, contains most of the Central Great Plains ecoregion, the 

western slopes of the Wichita Mountains, and eastern edges of 

the Southwestern Tablelands ecoregion (fig. 7). 

Region 2, consisted of two parts (Region 2a and Region 

2b, fig. 8). Region 2a, is in north central and northeast Oklahoma and is mostly in the Arkansas River Basin. Region 2a 

is separated on the eastern border by the Neosho River (fig. 

7) and contains the Central Irregular Plains and the Flint Hills 

ecoregions, and a part of the Cross Timbers ecoregion (fig. 7). 

Region 2b is in south-central Oklahoma and is mostly in the 

Red River Basin. Region 2b contains the Arbuckle Mountains 

and the eastern slopes of the Wichita Mountains (fig. 7). The 

drainage basins for the gaging stations in Region 2 had lower 

average soil permeability than drainage basins in Region 1 

or Region 3 (fig. 3), and the drainage basins for the gaging 

stations in Region 2 also had greater forested area (fig. 4) and 

greater annual precipitation than gaging stations in Region 1. 

Region 3 is in eastern and central Oklahoma. Region 3 

includes the Ozark Highlands ecoregion east of the Neosho 

River and the Ouachita Mountains to the south (fig. 7). The 

drainage basins for the gaging stations in Region 3 contained 

greater forested canopy (fig. 4) than other regions. Drainage 

basins in Region 3 commonly have greater annual precipitation, and greater spatial variability of annual precipitation, 

particularly in the southeastern mountains (figs. 5).

Separate regressions were developed by using gaging stations in each region. Estimates of annual mean and 

flow-duration statistics at ungaged sites are made by using 

the regression equation for the region where the ungaged 

stream site is located. An area-weighted average between 

the estimates from regression equations for each region can 

be used to estimate flow statistics at ungaged drainage-basins 

where the stream location is in one region but the contributing drainage-basin area crosses into another region (Risley 

and others, 2008; Hortness and Berenbrock, 2001). Even 

though hydrologic boundaries were used as part of the delineation process, four gaging stations that were used to develop 

regional regression equations had drainage areas that crossed 

a region boundary. Preliminary observations indicated that 

use of the area-weighted average typically helped to reduce 

the error of annual mean and flow-duration estimates at these 

gaging stations especially at lower exceedance probabilities 

(higher flows). Use of an area-weighted average also helps 

Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics
36 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Figure 7. Three regions used for developing regression equations relative to boundaries of level III ecoregions of Oklahoma and parts of adjacent states.

Albers Equal-Area Conic ProjectionNorth American Datum 1983

KANSAS

TEXAS

ARKANSAS

MISSOURI COLORADO

NEW

MEXICO

100°

33°

97°

94° 103°

31°

1

2b

3

2a Data Not Used

0 5025 MILES0 50 KILOMETERS

Wichita Ouachita

Arbuckle

MountainsRegression region boundaryState boundary

Stream

Neosho River

Red

River

U.S. Environmental Protection AgencyEcoregions (Level III) (Woods and others, 2005)

Arkansas Valley

Boston Mountains

Central Great Plains

Central Irregular Plains

Cross Timbers

Flint Hills

High Plains

Ouachita Mountains

Ozark Highlands

South Central Plains

Southern RockiesSouthwestern TablelandsTexas Blackland Prairies

EXPLANATION

Arkansas

River

Eastern Central Texas Plains
Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics at Unregulated Ungaged Stream Locations in Oklahoma Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics 37 Figure 8. Three regions used for developing regression equations and selected streamflow-gaging stations used to develop final regression equations after outliers were removed. Albers Equal-Area Conic Projection North American Datum 1983 KANSAS TEXAS

ARKANSAS

MISSOURI COLORADO

NEW

MEXICO

100°

33°

97°

94° 103°

31°

1

2b

3

2a Data Not Used

0 5025 MILES

0 50 KILOMETERS

EXPLANATION !

!

!

!

!

!

!

!

!

!

!

!

!

! !

!

!

!

! !

! ! ! ! !

!

!

!

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! !

!

!

!!

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!

!

!

!

!

!

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!

!

!

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!

!

!

!

!

!

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!

! ! !

!! !

!!! !

! ! !

!

!

! !

!

! ! !

! !

!

!

! !

!

! !

!

!

!

!

!

! !

! ! Regression region boundary

State boundary

Stream

Streamflow-gaging station and map number !

206

9

5

6

4

3

96

95

94

92

91 90

89

88

84

82

81

79

78

76

74 72

70

68

67

64

57

56

55

48

54

46 45

44

41

30

27

24

12

10

214 213

212 211

209

208

108

107

235

234 233

232

231 230

229

228

227

226

222

221

220

218

205

203

201

200

199

196

195

194

193

192

191

190

189 187

186

185

184

182

181

180

177

174

173

166

165

164

162

155

148

149

147

145

144

143

142

141

140

139

137

136

135

123

122

105

101

100

99

98

97

69

204

Red

River

Red

River

Arkansas

River !
38 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

to avoid an unnatural jump in estimates for ungaged locations 

along streams that cross region boundaries, and may help 

avoid an illogical progression of flow estimates downstream 

(for example, an estimate of the annual mean that is lower for 

a downstream site than an upstream site in another region). 

More information on the application of regression equations 

to estimate statistics at ungaged stream locations where the 

drainage area extends into another region is documented in the 

section titled “Example Computations”.

Methods Used to Develop Regression Equations

S-PLUS (Insightful Corporation, 2007) was used to 

derive equations that were used to estimate flow-duration 

and annual mean-flow statistics by using one or more drainage-basin characteristics. Separate regression equations 

were developed for each region by using gaging stations in 

those regions and for each of the five flow-duration statistics 

on the annual, summer-autumn, and winter-spring flow-duration curves, and for annual mean flow. This step resulted 

in 76 regression equations for each region, a total of 228 

regression equations. An overview of the methods used 

to develop the final regression equations for each region is 

detailed in figure 9.

Independent Variable Selection 

The parameters bn and bo (equation 4) for each regression equation were estimated from each dataset by using 

OLS procedures (Helsel and Hirsch, 1992). To select optimal 

independent variables for the regression equations, a forward 

and backward step-wise procedure (Ott, 1993, p. 656) and 

an overall method (Helsel and Hirsch, 1992, p. 312–314) 

were used. Twenty-three drainage-basin characteristics were 

considered as possible independent variables. Drainage-basin 

characteristics selected as final independent variables are listed 

in tables 7 and 8. Regression equations developed with flow 

statistics and drainage-basin characteristics in the original 

units occasionally resulted in extremely large intercepts that 

were larger than the coefficients of the independent variables. 

An equation with these inconsistencies can be cumbersome 

to compute manually and may result in a loss of accuracy if 

a large exponent on the intercept is rounded. The magnitude 

of the independent variable data was adjusted to make the 

intercept more balanced in magnitude with the regression 

coefficients. Drainage-basin characteristics were divided by a 

constant before being transformed into log space and used to 

develop the regression equations in each region (tables 9–11, 

back of report). The constant selected for each equation was 

the median for each drainage-basin characteristic used in the 

regression, based on drainage-basin characteristics for stations 

in the region used for regression analysis. This adjustment 

only changes the magnitude of the intercept and does not 

change the regression coefficients or the estimates of flow 

statistics.

During the creation of the regression equations, the two 

main regression diagnostics that were used to select a regression equation that produced the lowest error included the 

mean standard error of the estimate and adjusted coefficient 

of determination. The mean standard error of the estimate 

(referred to in this report as “standard error”) measures the 

deviation between the measured and predicted data points. A 

low standard error and high coefficient of determination (R2

)

are generally desirable in a regression analysis. The adjusted 

coefficient of determination (referred to in this report as 

adjusted R2

) is a measure of the percentage of the variation 

explained by the independent variables of the regression. The 

adjusted R2

 is adjusted on the basis of the degrees of freedom 

in the regression that is reduced by decreasing the number of 

independent variables in the regression equation (Helsel and 

Hirsch, 2002, p. 312–314). 

In addition to selecting regression equations with a low 

standard error and high adjusted R2

, common diagnostic statistics were used to evaluate and select independent variables 

for the final regression equations. These diagnostic statistics 

include the Predicted Residual Sum of Squares (PRESS), Mallow’s Cp, variance inflation factor (VIF), probability plot correlation coefficient (PPCC) test, and results of partial t-tests. 

Further documentation on use and definitions of these diagnostics can be found in Helsel and Hirsch (1992, p. 312–314). 

A p-value was calculated from the partial t-test, which presents 

the probably that the independent variable describes a statistically significant amount of variation of the dependent variable 

in the presence of other independent variables, with the critical 

p-value set at 0.05 (Helsel and Hirsch, p. 298–299).

Results from forward and backward step-wise procedures 

and the overall method produced possible regression equations 

by using drainage-basin characteristics to estimate each flow 

statistic. Regressions with the lowest standard errors and the 

highest adjusted R2

 values were selected for further evaluation. If several acceptable equations were available, the one 

with the lowest PRESS statistic (Helsel and Hirsch, 1992, p. 

248) and a low Mallow’s Cp value was selected (close to the 

number of parameters in the regression, Draper and Smith, 

1998, p. 332). In addition to these procedures, assurance was 

made that the error terms, ei

, from the model were normally 

distributed (by using a PPCC test) and monotonic (from visual 

examination of a plot of fitted values compared to the square 

of residuals) (Helsel and Hirsch, 1992, p. 228–234). 

Attempts were made to use the least number of variables 

possible to explain the most variation of the dependent variables. Occasionally, the regression equation with the lowest 

PRESS statistic and Mallow’s Cp contained a large number of 

independent variables. The use of too many independent variables with a small number of stations can create an equation 

that “over-fits” the data (Julie Kiang, U.S. Geological Survey, 

oral commun., October 2008; Risley and others, 2008) and 

can result in large equations that are impractical to compute. 

For this study, no more than four independent variables were 

selected for a final regression equation. If the preliminary 

regression equation contained more than four independent 
Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics at Unregulated Ungaged Stream Locations in Oklahoma Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics 39 Figure 9. Process used to develop regressions to estimate flow-duration and annual mean-flow statistics at ungaged stream locations in Oklahoma. (1) Selection of independent variables (using Ordinary Least Squares (OLS) regression procedures) Dataset for each flow statistic in each Region Do selected variables match for other flow- duration statistics for the same period and region? Combine optimal explanatory variables for other flow duration statistics on FDC Preliminary Regression (from OLS) Is the VIF for combined variables less than or equal to 6? Remove variable that is least statistically significant Are the total number of variables greater than 4? No Yes No Yes Yes No No Yes No Yes Select independent variables for each statistic (2) Modify regressions to handle zero flows in dataset Final Regression Use OLS regression from previous step Test delta constants to maximize R-squared minimize standard error Does dataset contain zero flow values? Run Tobit regression Is the intercept from OLS regression more than 5 percent of the intercept from the Tobit regression? Use Tobit Preliminary Regression Yes No No Yes No Yes Use OLS No EXPLANATION VIF, Variance Inflation Factor FDC, Flow Duration Curve OLS, Ordinary Least Sqaures Regression Flow Duration Statistics Annual Mean- Flow Statistics Select independent variables for each statistic Action Question Object Decision
40 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

variables, the variables that were the least statistically significant (had the highest p-value as a result of a partial t-test) were 

removed from the final regression.

The VIF, which is a measure of correlation between 

independent variables (Marquardt, 1970; Helsel and Hirsch, 

1992, p. 305–306), was minimized for any possible combination of independent variables to avoid multi-collinearity in the 

regression. Multi-collinearity can result in unreasonable slope 

coefficients. Helsel and Hirsch (1992) describe a rule that a 

VIF greater than 10 indicates a strong dependence between 

variables. A more conservative approach was taken for the 

regression analysis for this study, and combinations of independent variables were not accepted if the VIF was greater 

than 6.

An effort was made to use the same independent variables in the regression equations for estimating flow-duration 

statistics for the same period (annual, seasonal, or monthly) 

in each region. If the statistically significant independent 

variables were different between flow-duration regression 

equations for the same period, the independent variables were 

combined in the final equation as long as the VIF did not 

exceed 6. For example, for regression estimates of annual 

flow-duration statistics in Region 1, contributing drainage 

area, mean-annual precipitation at the gaging station, and outlet elevation, were the most significant independent variables 

(partial t-test resulted with the lowest p-value) to estimate 

the D20, D50, and D80, but mean June precipitation and channel slope were the most significant independent variables to 

estimate the D90 and D95. The total variables were greater than 

4, so one of the variables needed to be removed from the final 

regression. As a result of a partial t-test, outlet elevation was 

the least statistically significant independent variable to estimate the D20, D50, and D80, so this variable was removed from 

the regression. The VIF for the combined remaining variables 

did not exceed 6, and so the variables were combined for the 

final regression equation. This procedure generally resulted in 

streamflow estimates that consistently decreased with increasing exceedance probability along the same flow-duration curve 

(see section titled “Limitations”). However, some variables in 

the final regression equations may not account for a statistically significant amount of variation of the dependent variable 

(with p-values greater than 0.05 as a result of the partial t-test) 

because optimal regression coefficients were combined for 

flow-duration statistics along the same flow-duration curve. 

Flow statistics from gaging stations that were outliers 

were observed in the dataset during the regression equation 

creation process. These outliers had high influence on the 

slope coefficients of the independent variables. An outlier 

with high influence can occasionally produce a coefficient of 

determination that is substantially lower and a standard error 

that is substantially higher than would result from a dataset 

that did not contain an outlier (Helsel and Hirsch, 1992, p. 

245–246). As a rule, if any one outlier with high influence 

was observed for any given dataset that lowered the coefficient 

of determination by 15 percent, the outlier was removed from 

the dataset. Gaging stations that were removed from datasets 

are noted in the footnotes of table 1. Occasionally more than 

one outlier was removed from a dataset. Most outlier gaging 

stations had documentation of minor effects from anthropogenic activities. 

Selection of Regression Procedures to Handle 

Datasets with Zero Flow

Daily flows of zero cubic foot per second are frequently 

observed in Oklahoma. Intermittent flow also can be observed 

in small headwater drainage basins throughout the state. For 

flow-duration statistics, higher frequency of days with zero 

flow increase the probability that the D80, D90, or D95 flow 

exceedance will be equal to zero. Logarithmic transformation 

of zero is not possible; whereas, logarithmic transformation of 

flow-duration statistics is needed in order to create a best-fit 

linear regression equation. Alternative methods to simple OLS 

regression procedures were considered to account for flow 

exceedances equal to zero in a logarithmic transformation.

Many approaches can be used to treat the zero values 

in a regression analysis depending on the number of gaging 

stations with dependent variables equal to zero. One approach 

involves treating zero flow exceedances as “censored” at or 

less than zero flow. At times the streamflow may actually be 

zero, although at other times, flows may be non-zero but too 

small to be estimated by a rating curve and, therefore, reported 

as zero (Kroll and Stedinger, 1999).

If a sufficient number of dependent variables are censored (for example, a sufficient number of flow exceedances 

equal to zero), a Tobit regression (Ludwig and Tasker, 1993) 

can be used instead of an OLS regression. A Tobit regression 

is a model in which the dependent variable is censored, and 

a latent (that is unobservable) variable less than the censor 

is assumed. The Tobit procedure uses maximum likelihood 

estimation (MLE) to assume a distribution of data observations less than the lowest censored dependent variable (Tobin, 

1958). Kroll and Stedinger (1999) found that use of an OLS 

regression with left-censored data (data where observations 

are less than a minimum threshold and are considered latent 

variables), were not as accurate as a Tobit regression. The 

error residuals for an OLS regression derived by using leftcensored data will be biased higher than error residuals for 

a Tobit regression, especially at the lower end of the range 

of the dependent variable. However, OLS is an acceptable 

regression approach for small amounts of censoring (Kroll and 

Stedinger, 1999). 

 Tobit regression procedures will result in the same coefficients as an OLS if the dataset contains no censored values. 

As more observations are censored, or equal to zero, the 

resulting regression coefficients and intercept will start to differ between OLS and Tobit procedures. A Tobit regression is 

more computationally intensive than an OLS regression. For 

ease of reporting and data processing, a Tobit regression was 

applied only if the dataset contained flow exceedances equal to 

zero and the regression determination procedure resulted in an 
Development of Regression Equations to Estimate Flow-Duration and Annual Mean-Flow Statistics at Unregulated Ungaged Stream Locations in Oklahoma Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics 41

intercept that was 5 percent different from the regression that 

was developed by using OLS procedures.

In addition to the use of a Tobit regression, a delta constant also can be added prior to log transformation to avoid 

undefined logarithms (Perry and others, 2004). In preliminary 

observations, addition of a delta constant to regression datasets 

that had flow exceedances equal to zero increased the adjusted 

R2

 and decreased the standard error compared to estimates 

without a delta constant. To apply this method, the delta 

constant is subtracted from the final regression equation. The 

following modification was made to equation (2):

log (Yi

 – D)= bo + b11og X1 + b2log X2 + ... + bn log Xn + ei (6)

where 

D is a delta constant added to the dependent 

variable prior to log transformation.

The anti-log of the above is:

Yi = [10 bo *( X1

b1)*( X2

b2)...( Xnbn)*10 ei] - D (7)

Delta constants were used for OLS and Tobit regressions, 

but only for regression datasets that contained flow exceedances equal to zero (tables 2–6). For the Tobit regressions, 

the censor was set at the delta constant determined for each 

regression. Delta constants ranging from 0.01 to 10 were 

evaluated separately in the regression equations to determine 

an optimal delta constant for a regression. The value that produced a regression with the highest adjusted R2

 and the lowest 

standard error was selected. This approach was similar to that 

used by Perry and others (2004) and Risley and others (2008). 

Standard errors used to compare estimates to determine an 

optimal delta for each regression equation were computed by 

using error residuals from equation (6) for observations greater 

than zero only because error residuals may be excessively high 

for the log of observations less than 0.01 cubic foot per second 

after delta-subtraction. The use of a modified standard error 

to test regressions with censoring was similar to the approach 

used by Kroll and Stedinger (1999).

Bias Correction Factors

A linear regression equation provides an estimate of the 

mean response of the dependent variable. Estimates provided 

by equation 4 are in log units, and equations in tables 9–11 

(back of report) are presented in the original units. Linear 

regressions that use log-transformed variables predict the 

median, instead of the mean, response of the dependent variable. An estimated streamflow statistic based on a median 

response is biased because the estimated statistic tends to be 

lower than the mean (Ries and Friesz, 2000). Bias correction 

factors (BCFs) were used to correct the bias in retransformed 

logarithmic regression equations. Duan’s (1983) smearing 

estimate technique was selected as the appropriate BCF to 

use for the regression equations. This BCF is determined by 

computing the mean of the error residuals from a logarithmic 

regression equation after the error residuals have been converted to the original units, and multiplying the final estimate, 

once converted back to the original units, by the BCF. The 

BCF using Duan’s smearing estimate technique is computed 

from the following equation:

Duan

i=1

n

BCF =

10

n

ei

Σ

(8)

where,

BCFDuan is the bias correction factor,

ei is the regression residual and

n is the number of gaging stations in

 the regression.

The following equations show how the BCF is applied to 

regressions without and with a delta constant. For regressions 

without a delta constant, equation (9) was used to incorporate 

the BCF into the final regression equation. For equations 

where a delta constant was applied, BCFs were applied to 

regressions prior to the subtraction of the delta constant, and 

equation (10) was used.

Yi

 = BCFDuan *10 bo *( X1

b1)*( X2

b2)...( Xnbn)*10 ei (9)

Yi = [BCFDuan *10 bo *( X1

b1)*( X2

b2)...( Xnbn)*10 ei] - D (10)

An assumption for proper use of a BCF is that residuals 

are normally distributed. Non-normally distributed residuals 

may pose an issue for Tobit regressions. No constraints on 

the MLE were used to determine the lowest possible estimate 

less than the censor for Tobit regressions. For the final Tobit 

regression in log-space, this use of no constraints may result 

in non-normal error residuals for observations less than the 

censor that can be large and substantially skew the BCF. Only 

the error residuals (ei

) for observations of flow exceedances 

greater than the censor value were considered in equation 

(8), and the number of observations (n) was reduced accordingly to apply the BCF to Tobit regressions. For example, 

for the regression estimate for D95WSP in Region 2, out of 30 

observations 3 observations were equal to the censor (equal 

to zero cubic foot per second prior to addition of the delta 

constant and equal to 0.1 cubic foot per second after addition 

of the delta constant). The large error residuals from these 3 

observations would have substantially skewed the BCF. If 

error residuals from all 30 observations were used in equation 

(8) the BCF would have been equal to 2.35. Only the error 

residuals for 27 observations greater than the censor were used 

in equation (8) (n was changed from 30 to 27) that resulted in 

a BCF of 1.73. 
42 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Results of Regression Analysis to 

Estimate Flow-Duration and Annual 

Mean-Flow Statistics for Unregulated 

Ungaged Stream Locations in 

Oklahoma

Final regression equations for Regions 1–3 are listed in 

tables 9–11 (back of report) along with the adjusted R2

, standard error, and the median flow statistic (median of the dependent variable) for each dataset used to develop each regression 

equation. The regression equations include delta constants 

that ranged from 0.01 to 1.0 cubic foot per second. All final 

regression equations in tables 9–11 also incorporate the BCF.

Out of 137 gaging stations where flow-duration and 

annual mean-flow statistics were initially used in the regression analysis, statistics from only 113 gaging stations were 

used to develop the final regression equations (fig. 8). Region 

1 included 32 gaging stations, Region 2 included 30 gaging 

stations, and Region 3 included 51 gaging stations. Flow 

statistics from 24 gaging stations were statistical outliers in 

all regressions and were omitted from use in the regression 

analysis. 

Independent Variables in Regression Equations

From 23 drainage-basin characteristics used in the 

regression analyses (table 7), 13 drainage-basin characteristics 

were selected as independent variables for the final regression 

equations. Drainage-basin characteristics that were significant independent variables in the regression analyses were 

contributing drainage area (CONTDA); 10-85 channel slope 

(CSL10_85fm); mean hillslope (BSLDEM10M), mean elevation and stream outlet elevation (ELEV and OUTLETELEV, 

respectively); percent forest canopy (CANOPY_PCT); soil 

permeability (SOILPERM); mean annual, summer-autumn, 

winter-spring, April, June, and December precipitation 

(PRECIPOUT, PREG_06_10, PREG_11_05, APRAVPRE, 

JUNAVPRE, and DECAVPRE, respectively). The final 

independent variables selected for each regression differed 

between flow statistics and regions. 

The only independent variable that was included in every 

regression equation was drainage area. Contributing drainage 

area almost always had a positive relation with flow, especially 

annual mean flow and higher flow exceedances. Occasionally, 

drainage area was not related to some flow-duration statistics. Because optimal independent variables may have been 

different for estimating high-flow and low-flow exceedances 

for the same period, and those variables were combined in the 

final regressions, drainage area may not account for a statistically significant amount of variation of low-flow exceedances 

for these regressions that resulted in coefficients that are close 

or equal to zero. Non-significance of drainage area occurred 

for several equations in Region 1 for estimated low-flows 

(exceedance probability of 80 percent or greater) for the July 

through November monthly regressions. Drainage area was 

still included for several final equations where drainage area 

was not a statistically significant independent variable, but had 

a coefficient equal to zero (table 9). 

For many regression equations in Regions 1 and 2, 10-85 

channel slope was included as an independent variable. In 

Region 3, 10-85 channel slope was also a statistically significant variable for many regressions but had a significant 

negative correlation with drainage area and produced a VIF of 

greater than 6; therefore, channel slope could not be included 

in the final regression equations (fig. 9). In Region 1, 10-85 

channel slope typically had a negative relation to flow exceedance; whereas, in Region 2, 10-85 channel slope typically had 

a positive relation to flow exceedance. A possible explanation 

for the negative relation of slope to flow in Region 1 may be 

higher soil permeability in this region. Region 1 generally had 

higher soil permeability than Region 2 (fig. 3). Where soil 

permeability is greater, lower slopes can increase infiltration of 

runoff to groundwater, especially in high-permeability alluvial 

sediments that are more commonly near streams in Region 1. 

Drainage-basin hillslope was only included as an independent variable for the winter-spring, January, February, 

and July flow-duration regression equations in Region 1, and 

was not selected as an independent variable for regression 

equations in Regions 2 and 3. This variable was positively 

correlated to flow exceedance in most cases. A possible 

explanation may be because of increased runoff as a result of 

facilitated drainage from greater hillside slopes.

Soil permeability was selected only as an independent 

variable in the final regression equations to estimate October 

flow-duration statistics in Region 1, and was not statistically 

significant in any regression equations in Regions 2 or 3. 

Regional separation of regressions may have reduced the statistical significance of this variable by reducing the variability 

of soil permeability in each regional regression dataset.

Percent forest canopy was not included in most regression equations for Regions 1 or 2, where gaging stations in 

both regions contained less forested canopy than Region 3 

(fig. 4). Percent forest canopy was included in all regression 

equations in Region 3 except those used to estimate annual 

mean-flow and the April flow-duration statistics. Percent forest 

canopy almost always had a negative correlation to flow-duration statistics for Region 3 except for those used to estimate 

20th percentile flow-duration statistics for winter-spring, 

December, February, March, and May (D20WSP, DECD20, 

FEBD20, MARD20, and MAYD20, respectively). The negative 

correlation found in most flow-duration regressions may be the 

result of increased evapotranspiration from vegetation that can 

lower base flow during the growing season and may reduce 

recharge which can lower base flow during the non-growing 

season. All annual mean-flow regression equations, and flowduration regression equations in Regions 2 and 3, incorporated 

a precipitation parameter (which included annual, seasonal, 

or monthly mean precipitation at the gage). Precipitation 

parameters for Region 1 were not selected as independent 
Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics for Unregulated Ungaged Stream Locations in Oklahoma 43

variables for any of the December, January, February, March, 

or September flow-duration regressions. The type of precipitation parameter (annual, seasonal, or monthly) that were most 

significant for Region 1 regressions varied between regression 

equations. Either annual or winter-spring precipitation for 

Region 2 was the most significant precipitation variable. Typically annual or summer-autumn precipitation for flow-duration 

regressions for Region 3 was found to be the most significant 

precipitation variable. However, December precipitation was 

the most significant precipitation variable for the December 

and January flow-duration regressions, which are some of 

the driest months of the year. Precipitation coefficients were 

positive for most regressions that included a precipitation variable, indicating that flow increases with precipitation. For the 

June D95 (JUND95) estimate for Region 1, precipitation had a 

negative coefficient. The negative relation is not explainable, 

but could indicate that precipitation is a surrogate for another 

variable that had an effect on the JUND95 but was not included 

in the regression analysis.

Regression Accuracy

Regression accuracy can be assessed by looking at the 

adjusted R2

 and standard error (tables 9–11, back of report). 

Regressions with higher adjusted R2

 and lower standard errors 

are likely to produce more accurate estimates than regressions 

with lower adjusted R2

 and higher standard errors. The flowduration regression with the highest accuracy was the annual 

D20 in Region 3 with a standard error of 26.9 percent and an 

adjusted R2

 of 97.3 percent. The flow-duration regression with 

the lowest accuracy was the August D95 (AUGD95) in Region 1 

with a standard error of 293 percent and an adjusted R2

 of 29.3 

percent. The regression estimating annual mean-flow (AVE_

DV) with the highest accuracy was in Region 3 with a standard 

error of 18 percent and an adjusted R2

 of 98.8 percent. The 

regression estimating annual mean-flow with the lowest accuracy was in Region 1 with a standard error of 33.8 percent and 

an adjusted R2

 of 95.0 percent.

The accuracy of flow-duration regressions was generally 

observed to decrease from high-flow (low exceedance probability) to low-flow (high exceedance probability). A comparison of observed and regression estimated annual-flow statistics 

in Region 2 shows how regression uncertainty varies depending on the flow statistic (fig. 10). Uncertainty of a regression estimate can be seen graphically as a greater scatter of 

observed in relation to estimated points along a 1:1 line. For 

this example, a greater uncertainty exists for low-flow exceedances (D80, D90 and D95) than for annual mean flow and highflow exceedances (AVE_DV, D20, and D50). Accuracy generally decreased with a decrease in the median-flow exceedance 

(median of the dependent variable) used in regression datasets 

(fig. 11b). 

This decrease indicates a greater uncertainty is likely 

associated with low-flow estimates. Flow-duration statistics 

for high exceedance probabilities (low-flow exceedances) may 

be more uncertain than for lower exceedance probabilities 

because of an increased uncertainty in low-flow discharge 

computations from the rating curve (Dymond and Christian, 

1982; Rantz and others, 1983, p. 544–592). In addition, lowflow estimates from regression equations may be less accurate 

than high-flow estimates because base flow and low flow are 

largely affected by localized geological factors that cannot be 

easily quantified by using a regression approach (Riggs, 1972).

For the 225 flow-duration regression equations used to 

estimate flow-duration statistics in all regions and for all periods (annual, seasonal, and monthly), the D20 regression equations had a median standard error of 44.7 percent and a median 

adjusted R2

 of 91.6 percent, the D50 regression equations had a 

median standard error of 59.5 percent and a median adjusted 

R2

 of 87.6 percent, the D80 regression equations had a median 

standard error of 79.9 percent and a median adjusted R2

 of 102 

percent, the D90 regression equations had a median standard 

error of 150 percent and a median adjusted R2

 of 76.9 percent, 

and the D95 regression equations had a median standard error 

of 183 percent and a median adjusted R2

 of 71.9 percent. 

Monthly flow-duration regressions for February through 

June were generally more accurate than regressions for July 

through January (lower adjusted R2

 and higher standard error), 

especially for regressions that estimated low-flow exceedances (D80, D90, and D95). A possible explanation for the less 

accurate flow-duration regression equations for July through 

January could be low flows and an increase in water-use and 

evapotranspiration demands during summer months. November, December, and January have low precipitation, and the 

median values of most flow exceedances for gaging stations in 

each regional dataset were typically lower during these months 

as compared to regression datasets for February through June 

(fig. 11). Irrigation and other water use demands may be 

highest during July through September because of increased 

temperatures that may affect the variability of streamflow, 

especially low-flows, depending on antecedent soil-moisture 

and the extent of agricultural activities in the drainage basin. 

Evapotranspiration losses also are higher during this time of 

year because of increased temperatures, which can affect low 

flow. 

Similar to the results from the monthly flow-duration 

regression analysis, summer-autumn flow-duration regressions tended to have a lower accuracy (lower adjusted R2

 and 

higher standard error) than annual or winter-spring flowduration regressions. For flow-duration regression equations, 

winter-spring regressions tended to perform better than annual 

flow-duration regressions. The winter-spring period contained 

the wettest and driest periods of the year, but was less subject 

to high evapotranspiration demands and summer irrigation 

activities. 

Little difference was found in the adjusted R2

 for highflow estimates but large differences were found in the lowflow estimates when comparing accuracy of flow-duration 

regressions in each region. Low-flow estimates (D80, D90, and 

D95) for annual, summer-autumn, and winter-spring flow-duration regressions were substantially less accurate in Region 1 

Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics
44 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Figure 10. Comparison of the regression estimated and observed (A) annual mean flow and annual (B) 20th, (C) 50th, (D) 80th, (E) 

90th, and (F) 95th percentile flow exceedances for streamflow-gaging stations in Region 2. (OLS, Ordinary Least Squares)

-2

-1

0

1

2

3

4

-2

-1

0

1

2

3

4

-2 -1 0 1 2 3 4 -2 -1 0 1 2 3 4

-2

-1

0

1

2

3

4

)tnatsnocatled+citsitatswolf(dnocesrepteefcibucnistinu01golnicitsitatswolfdevresbO

Annual Mean-Flow

Regression estimated flow statistic in log 10 units in cubic feet per

second (flow statistic + delta constant)

R = 81.0 percent

Tobit Regression

delta = 0.2

2

R = 87.5 percent

OLS Regression

delta = 0.1

2

R = 91.6 percent

OLS Regression

delta = 0.0

2

R = 81.3 percent

Tobit Regression

delta = 0.1

2

R = 91.2 percent

OLS Regression

delta = 0.0

2

R = 95.1 percent

OLS Regression

delta = 0.0

2

A B

C D

E F

1:1 line

20th percentile flow

exceedance

50th percentile flow

exceedance

80th percentile flow

exceedance

90th percentile flow

exceedance

95th percentile flow

exceedance
Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics for Unregulated Ungaged Stream Locations in Oklahoma Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics 45

Figure 11. For each regression region in Oklahoma, (A) plots of median flow exceedances for datasets used to develop 

regression equations to estimate annual, seasonal, and monthly flow-duration statistics at ungaged streams and (B) plots of the 

adjusted coefficient of determination in relation to the log of median flow exceedances for regression datasets. The median of 

flow exceedances for regression datasets is the median observation (dependent variable) used in each regional regression.

20

30

40

50

60

70

80

90

100

20

30

40

50

60

70

80

90

100

20

30

40

50

60

70

80

90

100

-2 -1 0 1 2 3

0

50

100

150

200

250

300

350

400

450

500

0

50

100

150

200

250

300

350

400

450

500

0

50

100

150

200

250

300

350

400

450

500

dnocesrepteefcibucnistesatadnoissergerrofsecnadeecxewolffonaideM

feocdetsujdA tnecrepninoissergerfonoitanimretedfotneicif

Regression Period

Median of flow exceedances

for regression datasets in log of

cubic feet per second

20th Percentile Flow Exceedance

50th Percentile Flow Exceedance

80th Percentile Flow Exceedance

90th Percentile Flow Exceedance

95th Percentile Flow Exceedance

EXPLANATION

Region 1

Region 2

Region 3

Region 1

Region 2

Region 3

A B

Annual

Summer-Autumn

Winter-Spring

October

NovemberDecember

January

February

March

April

May

June

July

August

September
46 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

than estimates for the same flow exceedances in Regions 2 and 

3, where the adjusted R2

 typically was 60 percent or less for 

Region 1. Based on equations for Region 1 for all flow-duration curves, the median of the standard error of the estimate 

of the D20 and D95 was 46.2 and 208 percent, respectively. All 

flow-duration curves in Region 2 had a median of the standard error of the estimates of the D20 and D95 of 51.3 and 152 

percent, respectively. All flow-duration curves in Region 3, 

had a median of the standard error for the D20 and D95 of 36.5 

percent and 119 percent, respectively. The adjusted R2

 of 

the D20 and D95 for all regions had a median of 91.6 percent 

and 71.9 percent, respectively; whereas, the D95 for Region 

1 had a median adjusted R2

 of 45.9 percent, Region 2 had a 

median adjusted R2

 of 80.4 percent and Region 3 had a median 

adjusted R2

 of 76.5 percent. 

The accuracy of Region 1 low-flow estimates generally 

were less than the accuracy of low-flow estimates for Regions 

2 and 3. The reduced accuracy indicated a greater uncertainty 

associated with low-flow estimates in Region 1 and indicated 

the drainage-basin characteristics selected for regression 

analysis do not adequately describe the variability in low-flow 

estimates in Region 1. A possible source of variability in 

low-flow estimates in this region could be regional alteration 

from agricultural water-use activities, such as irrigation or 

withdrawals for livestock. Irrigation water uses vary across 

Oklahoma (Tortorelli, 2009) and are greater in the western 

part of the state. Although an attempt was made to eliminate 

gaging stations that were affected by local or regional irrigation and other water-use activities, these activities may not 

be sufficiently documented or may be difficult to detect from 

hydrograph inspection if these activities happened during the 

entire period of record used for analysis.

The large study area was divided into smaller more 

homogeneous regions that increased the accuracy of many 

regression equations. The differences in the accuracy of the 

regressions between Region 1 compared to Regions 2 and 

3 indicated that use of the regression regions substantially 

increased the accuracy of estimates for the latter regions, 

especially for low-flow estimates, compared to development 

of one set of regressions for the entire study area. Previous 

analysis indicated that development of flow-duration regressions by using gaging stations from the entire study area 

produced many median and low-flow regressions (D50, D80, 

D90, and D95) with similar if not higher uncertainty to the flowduration regressions in Region 1 (Esralew, 2009). Regionalization done by using a cluster analysis of gaging stations with 

similar drainage-basin characteristics most likely increased the 

accuracy of the estimates because of the physical diversity of 

the study area and because the influence that each independent 

variable has on streamflow likely varies across Oklahoma. 

Limitations

Use of the resultant regression equations should be 

limited to ungaged drainage basins in Oklahoma when the 

independent variables fall in the range of those sites used to 

develop the regression equations. The minimum and maximum values of all independent variables considered for each 

equation are shown in table 12. Accuracy of regression estimates can be improved when GIS datasets identical to those 

datasets used in the study are used to compute independent 

variables at ungaged sites. StreamStats is populated with the 

same GIS datasets used to develop the regression equations in 

this report. 

Data precision is decreased with regression equations 

that contain drainage-basin characteristics created from GIS 

datasets. Computer-generated GIS data typically are presented 

with arbitrary fixed decimal points. The precision of these 

data cannot always be assumed. Final flow statistics estimated 

from regression equations that were created from measured 

flow data and GIS data cannot be presented with a level of 

precision greater than 3 significant figures.

Users are cautioned about using the regression equations to estimate flow at ungaged sites. If these equations are 

used at ungaged stream sites that are substantially regulated 

for water supply, if the stream or drainage basin is affected 

by substantial diversions or withdrawals from either surface 

water or groundwater, or if the drainage basin is affected by 

urban change, the regression equations will produce estimates 

that are more likely to be characteristic of unregulated flow as 

opposed to actual flow at those sites.

The regression equations reported in tables 9–11 (back 

of report) can be used to estimate flow-duration and annual 

mean-flow statistics. However, the true value of the estimated 

flow statistic is unknown. Prediction intervals are a measure 

of uncertainty associated with the prediction made by the 

regression equation. The interval is the predicted value plus 

or minus a margin of error. A prediction interval is defined 

as the probability that the true value of the estimated statistic 

will fall in this margin of error (Hirsch and others, 1993). For 

example, a prediction interval at the 90-percent confidence 

level means a 90-percent chance that the true value of the 

characteristic will be in the margin of error. The margin of 

error includes the uncertainty in the independent variable 

estimate and the unexplained variability of the dependent variables. Prediction intervals are automatically calculated at the 

90-percent confidence level in the StreamStats program for all 

228 regression equations that were developed from this study. 

Equations used to compute prediction intervals and correct for 

bias in StreamStats can be found in Tasker and Driver (1988). 

Regressions that were developed to estimate flow-duration statistics for the same period (annually, seasonally, and 

monthly) can be used to construct an estimated flow-duration 

curve from the 20 percent to 95 percent exceedance probability by connecting a line from estimated flow-duration statistics. However, a possibility exists that for some combinations 

of drainage-basin characteristics used to estimate flow-duration statistics, an illogical progression of flow exceedances can 

happen. For example, an illogical progression of flow values 

for estimated summer-autumn flow-duration curve would be a 

higher estimated flow exceedance at the D95 than the D90. 
Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics for Unregulated Ungaged Stream Locations in Oklahoma 47 Table 12. Ranges of validity for basin characteristics used as independent variables in development of regressions to estimate flow-duration and annual mean-flow statistics for three regions in Oklahoma. [CONTDA, contributing drainage area, in square miles; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; BSLDEM10M, mean drainage-basin slope, in feet per foot; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; CANOPY_PCT, percentage of drainage-basin that is forested; SOILPERM, mean drainage-basin soil permeability in inches per year; PRECIPOUT, mean annual precipita- tion at the gage; PREG_06_10, summer-autumn precipitation, defined as the mean monthly precipitation for June through October at the gage, in inches; PREG_11_05, winter-spring precipitation, defined as the mean monthly precipitation for November through May at the gage, in inches; APRAVPRE, mean April precipitation at the gage, in inches; JUNAVPRE, mean June precipitation at the gage, in inches; DECAVPRE, mean December precipitation at the gage, in inches] Region Basin characteristic (abbreviation) CONTDA CSL 10_85fm BSLDEM10M ELEV OUTLE- TELEV CANOPY_ PCT SOIL- PERM PRECIPOUT PREG_ 06_10 PREG_ 11_05 APRAVPRE JUNAVPRE DECAVPRE Region 1 Minimum 3.65 3.73 1.76 1,121 923 0.28 0.26 26.1 13.0 12.5 2.16 3.36 1.00 Maximum 9,056 39.3 8.26 3,188 1,866 15.5 3.44 35.8 17.9 19.2 3.64 4.44 1.96 Region 2 Minimum 4.02 2.07 1.79 729 518 4.02 0.46 33.7 15.7 18.0 2.77 3.67 1.65 Maximum 7,159 27.0 7.95 1,640 1,190 23.3 1.66 45.6 21.7 24.8 4.35 5.36 3.03 Region 3 Minimum 8.00 1.98 2.85 625 305 8.41 0.96 38.0 17.1 20.7 3.49 4.35 1.96 Maximum 2,296 54.9 28.1 1,527 1,181 83.5 1.99 58.0 22.8 35.2 5.15 5.33 5.32

Results of Regression Analysis to Estimate Flow-Duration and Annual Mean-Flow Statistics
48 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Although an attempt was made to reduce the probability 

of an illogical progression of flow values along the same flowduration curve by using the same drainage-basin characteristics in each of the regressions for that flow-duration curve, a 

possibility exists that an illogical progression of flow values 

can occur. This illogical progression of flow estimates may 

occur because each regression equation used to estimate each 

flow-duration statistic along the same flow-duration curve 

was developed separately, and has variable prediction intervals depending on the size and variability of the dataset used 

to construct the regression. An illogical progression is more 

likely to occur for an estimated flow-duration curve where the 

regressions have a high uncertainty (low adjusted R2

 and high 

standard error). 

Illogical progressions can be corrected by using graphical 

methods. The exceedances for lower exceedance probabilities 

(D20, D50, and D80) can be plotted and a flow-duration curve 

can be manually extrapolated to recompute the D90 and D95

flow exceedances as long as the recomputed values are in the 

prediction interval (fig. 12).

Example Computations

The following example computation is the estimate of 

the 20-percent flow exceedance in March (MARD20) for an 

ungaged stream location in Region 3, but 20 percent of the 

contributing drainage area is in Region 2. The method for 

handling sites with parts of the drainage area in two regions 

has the following steps: (1) Calculate flow statistics for the 

entire drainage basin by using equations from the region 

where the stream site is located, (2) calculate flow statistics 

for the entire drainage basin by using equations from the 

upstream region, and (3) average the two values on the basis 

of the proportion of drainage area in each region (Hortness and 

Berenbrock, 2001). 

Assume that an ungaged stream location has a contributing drainage-basin area (CONTDA) of 850 mi2

, a forested 

canopy (CANOPY_PCT) of 40 percent, a channel slope 

(CSL10_85fm) of 10.0 ft/ft, an outlet elevation (OUTLETELEV) of 800 feet above NAVD 88, a mean-annual precipitation (PRECIPOUT) of 45.0 inches per year, and a mean 

winter-spring precipitation (PREG_11_05) of 23.5 inches per 

year.

From table 11:

MARD20 = 377*( CONTDA/203)1.02* (CANOPY_PCT/40.8)0.14* 

(PRECIPOUT/47.8)5.80 (12)

Applying drainage-basin characteristics to equation variables:

MARD20 = 377*(850 /203)1.02(40/40.8)0.14(45/47.8)5.80 (13)

Therefore,

MARD20 = 1,142 ft3

/s

From table 10:

MARD20=253*(CONTDA/323)1.05 * (CSL10_85fm/6.04)0.10 * 

(OUTLETELEV /783)0.27 * (PREG_11_05/22.0)5.82 (14)

Applying drainage-basin characteristics to equation variables:

MARD20 = 253*(850/323)1.05(10/6.04)0.10(800/783)0.27

(23.5/22.0)5.82 (15)

Therefore,

MARD20 = 1,085 ft3

/s

The computed MARD20 is then averaged between the two 

regions on the basis of drainage area:

MARD20 = 1,142 ft3

/s*(0.80) + 1,085 ft3/s(0.20) (16)

Therefore,

MARD20 = 1,130 ft3

/s

Summary 

Methods are presented for estimating flow-duration and 

annual mean-flow statistics for ungaged streams in Oklahoma 

in a cooperative study between the USGS and the Oklahoma 

Water Resources Board in order to provide flow statistics 

at sites of interest where measured flow data may not be 

available. Major components of the study included calculation of flow statistics at 235 gaging stations, calculation of 

physical and climatic drainage-basin characteristics at these 

stations, and development of regression equations to predict 

flow-duration and annual mean-flow statistics at ungaged 

stream locations based on drainage-basin characteristics. The 

statistics analyzed in this report are flow-duration statistics 

that included the (1) annual (period of record), (2) seasonal 

(summer-autumn and winter-spring), and (3) 12 monthly duration statistics, including the 20th, 50th, 80th, 90th, and 95th 

percentile flow exceedances, and the annual mean-flow (mean 

of daily flows for the period of record).

Daily mean discharge data from 235 continuous gaging 

stations were used to calculate flow-duration and annual meanflow statistics. Flow statistics were calculated for unregulated 

and anthropogenically affected periods of record of 10 or more 

years. Anthropogenic activities in this study included watersupply regulation, irrigation activity, and urban change.
Summary 49

A drainage-area ratio method is the preferred method for 

estimating flow statistics at an ungaged location that is on a 

stream near a gage. Streamflow statistics are computed for 

the index station, and the statistics are divided by the drainage area to determine streamflow per unit area at the gaging 

station. The method generally is reliable if the drainagearea ratio of the two sites is between 0.5 and 1.5. Where an 

ungaged location meets this criteria for gaging stations with 

known effects from regulation, irrigation activity, and urban 

change, this method can be used to estimate flow statistics 

during these circumstances as long as the statistics from 

the record at the gaging station used in the method also are 

affected by the same condition.

Regression equations that relate flow statistics to drainage-basin characteristics were developed for the purpose 

of estimating selected flow-duration and annual mean-flow 

statistics for ungaged streams that are not near gaging stations 

on the same stream. Regression equations were developed 

from flow statistics and drainage-basin characteristics for 113 

unregulated gaging stations. 

Separate regression equations were developed by using 

U.S. Geological Survey streamflow-gaging stations in regions 

with similar drainage-basin characteristics. These equations 

can increase the accuracy of regression equations used for 

estimating flow-duration and annual mean-flow statistics at 

ungaged stream locations in Oklahoma. Streamflow-gaging 

stations were grouped by selected drainage-basin characteristics by using a k-means cluster analysis. Three regions were 

identified for Oklahoma on basis of the clustering of gaging 

stations and a manual delineation of distinguishable hydrologic and geologic boundaries: Region 1 (western Oklahoma 

excluding the Oklahoma and Texas Panhandles), Region 2 

(north- and south-central Oklahoma), and Region 3 (eastern 

and central Oklahoma). 

A total of 228 regression equations (225 flow-duration 

regressions and three annual mean-flow regressions) were 

developed using ordinary least-squares and left-censored 

(Tobit) multiple-regression techniques. Equations were 

developed using logarithmic dependent variables. Because the 

log of zero cannot be taken, a small delta constant was added 

to all flow exceedances prior to log transformation for only 

those datasets that contained flow exceedances equal to zero. 

Tobit equations were used to estimate flow-duration statistics 

for datasets that had a substantial number of flow exceedances 

equal to zero. The Tobit procedure uses maximum likelihood 

estimation to assume a distribution of values less than the lowest censored value. For Tobit equations, the censor was set to 

the delta constant.

Figure 12. Example of a flow-duration curve with manual correction for an illogical progression of flow-duration statistics estimated 

from regression equations. An illogical progression occurs when a flow exceedance estimated at a higher exceedance probability is 

higher than an estimated flow exceedance at a lower exceedance probability.

1

10

100

0 50 100

Exceedance probability (percent)

illogical

progression

EXPLANATION

logical

estimate

Daily mean streamflow, in cubic feet per second

Estimated flow exceedance

from regression

Upper and lower

90-percent

confidence interval

Estimated 95-percent flow

exceedance from best-fit

line drawn through flow

exceedance estimates for

the 20-,50-,80-, and 90-percent

exceedance probabilities
50 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Drainage-basin characteristics that were statistically significant independent variables in the regression analyses were 

(1) contributing drainage area; (2) elevation at the gage; (3) 

mean drainage-basin elevation; (4) channel slope; (5) percentage of drainage-basin covered by forest canopy; (6) mean 

drainage-basin hillslope; (7) mean drainage-basin soil permeability; and (8) mean annual, seasonal, and monthly precipitation at the gage. 

Flow-duration equations were more accurate for estimating flow at lower exceedance probabilities (D20 and D50) than 

for estimating flow at higher exceedance probabilities (D80, 

D90, and D95. This decrease in accuracy may have occurred 

because there was a greater uncertainty for low-flow estimates. 

Low-flow is largely affected by localized geology that was not 

quantified by the drainage-basin characteristics selected for 

use in the regression analysis.

Regression estimates of flow-duration statistics for February through June were generally more accurate than regression 

estimates of flow-duration statistics for July through January (lower adjusted coefficient of determination and higher 

standard error), especially for regressions estimating lower 

flow exceedances (D80, D90, and D95). A possible explanation 

for the less accurate flow-duration regression estimates for 

July through January could be lower flows and an increase 

in water-use and evapotranspiration demands during summer 

months. 

The standard errors of estimate of regression equations 

for Region 1 (western Oklahoma) were generally larger than 

those standard errors for other regions, especially for low-flow 

exceedances. These errors may be a result of greater variability in low flow because of increased irrigation activities in this 

region.

Regression equations may not be reliable for sites where 

the drainage-basin characteristics are outside the range of 

values of independent variables that were used to develop 

the regression equations. The equations are not accurate for 

streams regulated by water-supply reservoirs, streams that are 

substantially affected by local irrigation withdrawals from 

groundwater or surface water, or streams that are affected by 

urban change.

Regressions that were developed to estimate flow-duration statistics for the same period (annually, seasonally, and 

monthly) can be used to construct an estimated flow-duration 

curve from the 20 percent to 95 percent exceedance probability by connecting a line from estimated flow-duration statistics. However, a possibility exists that for some combinations 

of drainage-basin characteristics used to estimate flow-duration statistics, an illogical progression of flow exceedances 

along a flow-duration curve can happen. Illogical progressions can be corrected by using graphical methods. The 

exceedances for lower exceedance probabilities (D20, D50, and 

D80) can be plotted and a flow-duration curve can be manually 

extrapolated to recompute the D90 and D95 flow exceedances as 

long as the recomputed values are in the prediction interval.

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52 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

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Tables 53

Tables
54 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma
Tables 55

Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued[Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Annual 

mean 

Flow-duration statistics

D20 D50 D80 D90 D95 D20SUM D50SUM D80SUM D90SUM D95SUM D20WSP D50WSP D80WSP D90WSP D95WSP

1 07146500 U 1,350 1,490 587 279 180 113 2,180 667 238 155 107 1,230 558 304 208 130

R 2,160 2,550 1,050 484 351 265 3,070 1,070 422 285 206 2,260 1,040 521 405 324

2 07148140 R 3,180 5,020 1,420 333 181 141 5,380 1,340 177 140 122 4,720 1,470 257 166 134

3 07148350 U 96.0 95.7 34.7 3.00 0.35 0.09 88.2 11.3 0.35 0.07 0.00 98.6 44.2 18.5 7.78 1.14

4 07148400 U 142 151 51.2 11.9 2.58 0.70 145 30.6 3.36 1.08 0.05 154 61.9 27.5 13.0 2.84

5 07149000 U 153 172 88.1 35.7 14.1 1.66 150 51.1 11.9 1.23 0.00 180 104 64.9 51.4 36.66 07149500 U 393 322 126 31.7 2.37 0.03 333 65.8 1.10 0.03 0.01 316 147 74.6 48.2 29.0

7 07150500 R 407 486 146 15.7 5.27 2.62 523 83.0 12.5 6.06 3.90 468 174 29.6 4.04 1.67

8 07151000 R 937 987 273 69.1 36.7 19.8 1,050 224 58.8 34.0 19.5 963 305 87.2 39.3 20.19 07151500 U 262 243 103 42.4 21.2 9.63 234 71.2 21.2 8.83 2.31 247 118 63.1 44.1 30.6

10 07152000 U 604 438 154 55.5 26.0 8.31 408 117 29.7 8.91 3.77 451 173 81.1 49.8 30.3

11 07152500 U 4,830 5,450 1,930 741 463 302 6,570 2,130 704 403 239 4,700 1,840 765 506 358

R 6,410 9,910 3,060 868 490 347 10,200 2,980 726 433 296 9,690 3,110 997 551 390

12 07153000 U 215 119 17.3 3.38 1.13 0.27 98.6 13.1 2.02 0.49 0.03 139 20.2 4.51 1.99 0.75

13 07153100 R 10.3 0.87 0.04 0.01 0.01 0.00 0.22 0.03 0.01 0.01 0.00 1.46 0.04 0.02 0.01 0.00

14 07154500 U 28.5 4.37 1.59 0.20 0.03 0.02 11.2 1.76 0.05 0.02 0.01 3.01 1.55 0.36 0.04 0.02

UI 9.84 2.26 0.27 0.00 0.00 0.00 2.48 0.02 0.00 0.00 0.00 2.20 0.54 0.03 0.00 0.00

15 07155000 U 40.8 21.2 2.02 0.03 0.01 0.01 46.9 0.86 0.02 0.01 0.01 13.8 2.61 0.03 0.01 0.01

16 07155590 U 19.9 0.17 0.00 0.00 0.00 0.00 0.50 0.00 0.00 0.00 0.00 0.12 0.00 0.00 0.00 0.00

UI 3.46 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00

17 07156900 U 86.0 88.0 65.8 48.5 40.4 34.0 80.0 55.6 40.6 34.2 29.5 90.3 71.4 56.7 49.8 44.0

UI 36.8 44.9 35.5 27.1 22.7 19.9 35.1 28.6 22.1 19.5 17.7 48.1 40.6 33.4 30.5 28.3

18 07157000 U 101 98.9 60.4 37.6 27.3 19.7 97.9 50.0 28.0 19.4 14.0 99.3 66.7 46.3 37.3 30.2

19 07157500 U 51.7 26.9 14.5 6.00 0.21 0.03 39.1 9.53 0.05 0.02 0.01 25.5 16.3 10.0 7.25 5.51

UI 10.7 14.0 8.35 4.57 2.95 1.62 11.6 5.30 2.59 1.39 0.72 14.7 9.81 6.90 5.62 4.84
56 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued [Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Annual mean Flow-duration statistics

D20

D50

D80

D90

D95 D20SUM

D50SUM

D80SUM

D90SUM

D95SUM

D20WSP

D50WSP

D80WSP

D90WSP

D95WSP

20 07157900

U 3.45 2.40 1.53 0.89 0.63 0.49 1.98 1.15 0.64 0.48 0.32 2.57 1.72 1.18 0.97 0.71

21 07157950

U 118 143 51.4 3.83 0.08 0.00 107 11.4 0.02 0.00 0.00 156 74.1 27.1 13.2 4.82

22 07157960

U 13.3 12.6 2.18 0.10 0.00 0.00 9.76 0.52 0.00 0.00 0.00 14.0 3.60 0.95 0.25 0.00

23 07158000

U 291 271 90.1 11.7 0.77 0.00 267 42.6 0.44 0.00 0.00 273 114 38.1 15.5 4.43

24 07158400

U 41.1 20.8 8.29 4.46 2.83 1.93 16.7 6.92 3.13 1.90 1.30 24.6 9.51 5.40 3.97 2.90

25 07159000

U 48.9 12.1 2.08 0.22 0.00 0.00 13.7 1.23 0.00 0.00 0.00 11.3 2.55 0.44 0.20 0.08

26 07159100

U 889 908 286 102 59.0 40.8 852 211 61.7 40.0 27.8 939 333 148 95.5 67.2

27 07159750

U 183 153 59.6 28.6 20.1 16.5 130 47.0 23.6 17.2 13.7 171 68.0 36.7 23.0 18.7

28 07160000

U 1,170 1,620 579 246 153 98.7 1,460 428 154 99.4 73.0 1,720 667 328 241 186

29 07160350

U 38.0 24.5 12.7 6.73 5.14 4.04 21.7 10.2 5.45 4.10 3.33 25.7 14.2 7.87 6.19 5.35

30 07160500

U 142 70.7 17.2 6.49 4.02 2.83 65.4 14.8 5.10 3.13 1.63 73.9 18.6 7.68 4.98 3.57

31 07163000

U 12.8 3.56 0.50 0.00 0.00 0.00 1.68 0.01 0.00 0.00 0.00 4.94 1.08 0.12 0.00 0.00

32 07163500

U 1,240 1,240 325 103 58.5 29.5 1,700 448 120 58.2 21.0 872 265 96.5 58.7 35.6

33 07164000

U 1,740 1,840 534 206 109 63.8 2,310 670 172 89.1 62.6 1,450 493 224 135 65.4

34 07164500

U 6,550 7,490 2,560 981 610 380 10,000 3,140 988 535 320 5,940 2,350 978 656 455

R 8,750 13,200 4,310 1,270 638 313 13,000 4,540 1,450 738 348 13,400 4,140 1,140 585 295

35 07164600 UUrb 21.4 10.3 2.88 1.40 1.03 0.83 8.21 2.22 1.17 0.89 0.76 11.6 3.39 1.65 1.20 0.95

36 07165500

R 48.4 31.0 1.92 0.00 0.00 0.00 22.7 0.77 0.00 0.00 0.00 37.8 4.03 0.00 0.00 0.00

37 07165562 UUrb 22.1 10.3 2.24 0.37 0.00 0.00 6.63 0.81 0.00 0.00 0.00 12.5 3.17 0.95 0.49 0.23

38 07165565 UUrb 7.29 4.61 0.88 0.13 0.01 0.00 3.25 0.41 0.02 0.00 0.00 5.34 1.20 0.31 0.14 0.02

39 07165570

R 10,700 16,900 5,670 1,640 891 615 15,600 5,560 1,610 934 648 17,700 5,770 1,660 858 594

40 07170500

U 1,530 1,130 238 28.3 10.4 3.80 998 131 19.2 7.41 2.32 1,190 318 44.0 13.0 6.05

R 2,150 3,490 421 57.4 33.1 23.5 2,520 182 45.2 29.2 21.0 3,960 650 79.3 37.2 25.8
Tables 57

Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued[Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Annual 

mean 

Flow-duration statistics

D20 D50 D80 D90 D95 D20SUM D50SUM D80SUM D90SUM D95SUM D20WSP D50WSP D80WSP D90WSP D95WSP

41 07170700 U 26.5 11.6 1.64 0.02 0.00 0.00 4.34 0.31 0.00 0.00 0.00 16.3 3.48 0.39 0.08 0.00

R 26.9 24.0 0.52 0.00 0.00 0.00 11.3 0.09 0.00 0.00 0.00 33.0 2.35 0.01 0.00 0.00

42 07171000 U 2,080 1,620 249 22.5 8.11 3.59 1,560 171 17.9 6.07 2.29 1,650 318 27.5 9.49 5.34

R 2,770 4,230 601 74.2 38.9 24.4 3,020 259 53.7 31.5 20.0 4,850 903 123 48.8 29.6

43 07171400 R 2,840 4,910 511 28.9 9.71 2.71 3,840 146 26.5 9.15 3.70 5,840 811 31.0 10.3 2.17

44 07172000 U 283 248 41.6 2.64 0.08 0.00 116 16.3 1.01 0.00 0.00 321 73.9 5.71 0.54 0.00

45 07173000 U 406 397 29.8 10.1 5.07 2.01 175 20.0 9.45 4.32 1.83 540 57.4 10.7 5.66 2.26

46 07174200 U 254 152 17.6 1.06 0.11 0.00 78.4 7.83 0.38 0.00 0.00 199 27.9 2.70 0.30 0.09

47 07174400 R 1,190 2,220 105 28.1 18.3 10.4 1,560 48.0 26.7 19.4 14.5 2,560 291 30.1 16.2 7.12

48 07174600 U 86.1 50.9 9.07 0.44 0.00 0.00 19.3 2.27 0.00 0.00 0.00 78.0 18.9 3.25 0.57 0.00

49 07174700 R 985 1,150 103 24.7 16.0 11.3 554 54.4 20.3 14.1 10.4 1,550 179 31.3 18.5 12.6

50 07175000 U 1.42 1.05 0.00 0.00 0.00 0.00 0.14 0.00 0.00 0.00 0.00 1.35 0.14 0.00 0.00 0.00

51 07175500 R 1,660 3,060 266 52.2 36.5 26.0 2,030 96.5 42.7 34.0 26.3 3,650 506 71.7 42.7 25.4

52 07176000 U 3,720 3,850 577 56.3 18.6 6.23 3,750 379 43.0 11.8 2.26 3,890 764 75.8 25.2 11.0

R 4,500 8,650 919 91.6 55.5 37.8 6,290 330 81.6 54.5 37.3 10,100 1,530 117 56.5 38.1

53 07176465 R 45.5 21.1 5.63 2.27 1.37 0.84 15.3 6.24 3.31 1.68 1.18 43.2 5.30 1.97 1.18 0.23

54 07176500 U 200 110 12.1 0.41 0.00 0.00 72.8 5.27 0.00 0.00 0.00 140 18.7 1.45 0.00 0.00

R 304 265 43.3 14.0 7.39 5.14 123 26.8 11.1 6.19 4.62 400 67.9 16.0 8.59 5.83

55 07176800 U 25.5 9.69 1.00 0.00 0.00 0.00 2.96 0.14 0.00 0.00 0.00 15.1 2.42 0.23 0.00 0.00

56 07177000 U 181 72.7 10.9 1.20 0.14 0.00 46.0 5.81 0.37 0.00 0.00 93.3 15.7 2.36 0.54 0.08

57 07177500 U 483 248 40.1 7.09 2.55 0.70 159 24.8 4.50 1.48 0.14 325 55.6 10.6 3.91 1.20

R 748 831 178 80.9 61.3 50.4 407 180 127 65.8 31.3 1,100 172 73.7 60.4 52.7

58 07177650 UUrb 6.59 3.33 0.59 0.08 0.02 0.00 0.92 0.21 0.02 0.00 0.00 5.04 1.19 0.23 0.07 0.02

59 07177800 UUrb 8.77 6.33 2.33 0.79 0.39 0.22 4.84 1.34 0.41 0.22 0.14 7.35 2.88 1.32 0.88 0.53

60 07178000 R 812 880 201 115 84.8 73.2 492 202 160 130 79.1 1,190 199 95.5 79.8 71.8
58 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued [Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Annual mean Flow-duration statistics

D20

D50

D80

D90

D95 D20SUM

D50SUM

D80SUM

D90SUM

D95SUM

D20WSP

D50WSP

D80WSP

D90WSP

D95WSP

61 07178040 UUrb 87.1 55.4 14.4 3.90 2.52 1.90 36.6 6.64 2.58 1.94 1.51 70.0 20.6 7.13 4.13 2.99

62 07178200

R 991 1,160 291 177 137 113 795 276 197 172 155 1,400 312 154 123 106

63 07178600

U 4,480 5,240 687 98.4 50.8 33.8 5,240 508 73.7 39.5 20.5 5,240 873 133 61.0 41.7

64 07184000

U 166 75.4 11.5 0.56 0.00 0.00 43.1 3.31 0.09 0.00 0.00 98.8 19.4 2.84 0.11 0.00

65 07185000

U 3,650 3,860 788 135 21.9 6.90 4,360 718 123 20.0 0.96 3,550 845 144 22.7 10.4

R 3,880 5,950 1,030 144 69.1 43.1 5,930 710 119 60.9 38.7 5,970 1,260 192 74.8 48.1

66 07185095 UUrb 58.7 36.8 10.2 2.83 1.54 0.82 16.6 4.19 1.83 1.16 0.56 57.8 16.7 5.93 3.40 1.17

67 07185500

U 2.88 2.42 0.42 0.00 0.00 0.00 0.90 0.13 0.00 0.00 0.00 3.24 1.05 0.12 0.00 0.00

68 07185700

U 238 314 130 63.5 46.6 37.6 232 113 61.6 44.6 35.9 362 153 65.0 47.9 39.2

69 07185765

U 381 490 200 86.6 56.9 44.7 294 141 68.6 50.1 40.8 599 292 106 66.0 49.7

70 07186000

U 939 941 301 99.9 63.1 45.6 624 191 84.0 56.3 39.7 1,100 422 125 70.5 49.9

71 07186400

U 205 250 97.4 42.3 32.7 26.5 138 65.3 37.6 29.5 22.9 324 145 50.1 36.2 29.7

72 07187000

U 417 524 235 114 86.0 68.5 373 183 104 81.3 64.2 628 291 125 91.5 71.9

73 07187500

U 400 483 236 115 82.8 65.0 484 204 101 71.3 54.2 482 259 129 92.9 74.3

74 07188000

U 2,170 2,430 848 310 207 151 1,610 572 264 181 133 2,890 1,150 366 232 171

75 07188500

U 28.1 35.9 12.7 5.14 3.63 2.57 31.1 12.2 4.76 2.28 1.34 39.1 13.2 5.31 3.99 3.41

76 07189000

U 808 1,000 339 127 86.0 66.4 499 193 95.0 69.9 53.5 1,310 523 190 117 83.1

77 07189500

U 6,070 6,380 2,250 848 544 370 5,640 1,530 644 376 239 6,880 2,850 1,080 741 514

78 07189540

U 5.28 5.06 3.16 2.25 1.95 1.71 3.89 2.62 1.99 1.75 1.61 5.92 3.63 2.57 2.23 1.98

79 07189542

U 31.2 37.4 17.7 9.45 7.46 6.26 20.2 12.1 7.36 5.90 4.81 46.8 24.9 13.7 10.2 8.60

80 07190500

R 7,510 11,900 3,930 588 90.7 31.6 11,200 3,650 649 84.2 30.2 12,300 4,220 552 96.6 35.3

81 07191000

U 343 187 32.1 3.07 1.65 1.09 72.3 8.19 1.86 1.11 0.76 267 65.0 9.19 2.70 1.68

82 07191220

U 117 135 54.1 22.5 14.6 10.9 69.2 33.1 16.3 11.7 7.75 180 79.7 33.0 21.1 13.9

83 07191500

R 8,830 14,000 4,890 403 212 162 12,200 3,790 369 208 164 15,900 6,220 449 216 160
Tables 59

Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued[Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Annual 

mean 

Flow-duration statistics

D20 D50 D80 D90 D95 D20SUM D50SUM D80SUM D90SUM D95SUM D20WSP D50WSP D80WSP D90WSP D95WSP

84 07192000 U 131 61.0 4.71 0.11 0.03 0.01 30.0 1.91 0.04 0.02 0.01 78.4 8.62 0.21 0.04 0.02

85 07192500 R 10,400 12,100 4,430 1,860 596 301 12,300 4,020 1,820 454 186 12,000 4,790 1,870 632 379

86 07193500 R 8,450 13,200 4,270 724 153 27.4 11,600 3,850 782 129 19.3 14,100 4,870 691 174 39.7

87 07194500 U 21,600 26,300 8,690 3,490 2,230 1,340 29,600 8,160 3,040 2,010 1,150 25,000 9,060 3,950 2,440 1,450

R 20,300 33,400 10,800 3,520 1,990 1,340 33,400 11,300 4,140 2,660 1,650 33,500 10,400 2,950 1,750 1,190

88 07194800 U 145 158 36.9 12.6 9.18 7.37 49.8 16.7 9.54 7.39 5.74 226 78.3 23.2 13.5 10.1

89 07195000 U 124 150 79.2 41.4 28.7 23.4 112 68.3 37.6 26.4 20.4 177 93.2 45.1 31.0 25.1

90 07195430 U 531 584 281 160 126 109 332 188 135 114 100 742 380 217 161 118

91 07195500 U 621 739 293 139 103 76.6 394 190 113 85.5 66.3 976 427 183 129 96.3

92 07195800 U 14.9 18.1 8.32 4.54 3.29 2.55 11.6 6.04 3.56 2.59 1.95 22.5 11.0 6.03 4.31 3.31

93 07195855 R 46.0 61.1 25.3 11.1 6.77 4.72 32.7 14.8 7.44 5.30 3.54 77.6 36.1 17.3 11.3 6.48

94 07195865 U 21.5 22.2 11.7 6.91 5.63 4.78 15.5 8.33 5.84 4.84 4.13 26.4 14.3 8.55 6.82 5.75

95 07196000 U 115 134 55.5 25.5 18.6 14.4 77.2 34.6 20.6 15.3 12.1 175 77.1 35.0 23.8 17.7

96 07196500 U 929 1,150 422 180 123 90.2 609 264 137 94.7 65.2 1,520 635 248 168 121

97 07196900 U 44.9 47.9 12.8 2.10 0.92 0.43 14.7 3.24 0.89 0.40 0.24 67.7 25.6 7.18 3.42 1.80

98 07196973 U 24.8 35.2 11.3 2.45 0.25 0.00 13.1 3.68 0.07 0.00 0.00 49.2 19.3 7.73 3.81 2.50

99 07197000 U 325 390 125 40.0 24.2 16.0 168 60.5 26.8 16.5 9.64 538 210 67.5 38.6 25.3

100 07197360 U 83.1 93.6 37.2 14.9 11.0 8.37 44.6 19.3 12.0 8.83 6.91 127 56.4 25.5 14.7 10.2

101 07198000 U 1,960 2,310 749 297 211 172 1,400 474 233 176 143 2,970 1,110 368 259 208

R 1,500 2,320 868 125 72.9 52.4 1,550 621 118 79.3 54.8 3,030 1,150 139 68.0 51.5

102 07228500 U 469 268 47.0 15.1 7.50 2.45 497 44.8 5.93 1.00 0.03 205 47.9 19.5 14.8 11.9

R 317 359 130 26.7 13.4 6.80 237 41.1 11.9 5.79 2.72 410 189 73.8 40.5 24.4

103 07229100 R 359 331 90.7 14.8 6.25 4.78 213 40.3 6.06 4.54 3.10 406 135 39.2 18.3 10.3

104 07229200 R 765 850 341 105 40.0 17.0 654 184 42.1 16.6 5.97 967 420 203 125 62.6
60 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued [Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Annual mean Flow-duration statistics

D20

D50

D80

D90

D95 D20SUM

D50SUM

D80SUM

D90SUM

D95SUM

D20WSP

D50WSP

D80WSP

D90WSP

D95WSP

105 07229300

U 84.8 68.1 24.0 5.94 2.24 0.58 48.7 16.1 1.97 0.51 0.28 81.0 30.2 11.6 6.16 4.12

106 07230000

U 58.9 32.8 7.61 1.81 0.55 0.18 23.2 5.18 0.54 0.16 0.05 37.3 8.84 2.79 1.76 1.07

R 55.7 1.19 0.65 0.41 0.24 0.18 1.12 0.67 0.41 0.25 0.19 1.31 0.64 0.41 0.24 0.18

107 07230500

U 149 82.0 23.1 5.41 2.00 0.05 66.3 13.9 2.33 0.04 0.02 97.4 29.7 9.36 4.57 2.86

R 146 151 19.1 4.78 2.13 0.54 67.7 9.93 1.96 0.28 0.00 207 27.3 8.39 4.49 2.96

108 07231000

U 453 277 59.9 16.0 7.40 3.26 223 41.1 7.93 2.85 0.23 313 74.0 25.1 13.6 9.38

R 357 421 55.6 8.80 1.92 0.26 228 24.6 2.68 0.29 0.00 550 87.5 21.9 7.49 2.29

109 07231500

U 1,840 1,680 319 61.2 21.8 6.81 2,270 316 31.7 6.84 0.66 1,330 320 90.3 39.1 20.3

R 1,740 2,100 505 105 33.4 12.1 1,510 245 37.1 12.3 3.80 2,440 705 222 101 43.1

110 07232000

U 564 342 43.0 2.89 0.47 0.04 97.4 9.55 0.58 0.04 0.02 615 98.7 17.5 5.05 0.93

111 07232500

U 27.9 11.3 5.88 1.35 0.53 0.00 10.4 2.10 0.40 0.00 0.00 11.4 7.12 4.38 2.78 1.91

UI 2.61 0.91 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 2.10 0.00 0.00 0.00 0.00

112 07232900 UI 1.27 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

113 07233000

U 15.5 7.09 2.87 0.03 0.02 0.01 5.45 0.04 0.02 0.01 0.00 7.42 4.25 1.62 0.04 0.02

114 07233500

U 21.2 3.21 0.74 0.01 0.00 0.00 8.09 1.09 0.00 0.00 0.00 1.98 0.63 0.14 0.00 0.00

115 07233650

R 0.90 1.45 0.79 0.11 0.00 0.00 0.64 0.13 0.00 0.00 0.00 1.77 1.14 0.71 0.49 0.40

116 07234000 RI 13.2 13.6 0.57 0.01 0.00 0.00 7.73 0.15 0.00 0.00 0.00 15.7 3.27 0.11 0.01 0.00

U 115 54.0 14.1 0.00 0.00 0.00 92.3 3.12 0.00 0.00 0.00 46.4 18.5 1.16 0.00 0.00

117 07234100

U 6.54 3.04 2.17 1.46 1.13 0.87 2.56 1.65 1.08 0.84 0.64 3.21 2.42 1.85 1.61 1.48

118 07234500

U 186 135 29.1 0.05 0.02 0.01 202 16.6 0.03 0.02 0.01 115 34.6 3.72 0.03 0.02

119 07235000

R 13.9 8.79 4.82 1.43 0.49 0.19 10.1 2.66 0.45 0.14 0.00 8.36 5.56 3.26 2.07 1.17

RI 8.36 5.29 2.13 0.79 0.54 0.41 4.33 1.30 0.55 0.40 0.30 5.87 2.59 1.24 0.82 0.62

120 07236000

U 95.0 68.3 33.3 5.61 0.05 0.02 73.3 13.0 0.04 0.02 0.01 66.9 41.0 21.3 13.4 4.70

121 07237000

R 64.5 52.0 4.97 0.95 0.50 0.16 28.4 1.74 0.59 0.27 0.04 54.8 22.8 1.43 0.83 0.41

RI 41.6 58.7 18.9 1.51 1.05 0.81 33.2 2.83 1.05 0.80 0.68 68.2 31.7 2.09 1.43 1.23
Tables 61

Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued[Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Annual 

mean 

Flow-duration statistics

D20 D50 D80 D90 D95 D20SUM D50SUM D80SUM D90SUM D95SUM D20WSP D50WSP D80WSP D90WSP D95WSP

122 07237500 U 216 170 44.3 1.30 0.00 0.00 246 20.4 0.00 0.00 0.00 152 56.6 5.05 0.77 0.00

RI 107 160 59.1 14.0 7.14 4.34 120 31.8 7.52 3.99 2.58 176 79.7 27.6 13.2 8.59

123 07238000 U 237 205 58.8 0.49 0.00 0.00 287 30.2 0.00 0.00 0.00 182 76.4 5.78 0.00 0.00

RI 164 241 93.7 31.4 13.2 5.73 186 50.7 11.6 4.27 0.94 262 121 54.9 36.9 25.2

124 07239000 U 273 277 60.1 0.05 0.02 0.01 336 27.7 0.03 0.01 0.01 248 77.0 9.66 0.04 0.02

R 154 160 13.5 4.00 2.81 2.08 159 14.9 4.70 2.93 1.90 160 12.5 3.73 2.76 2.15

125 07239300 R 197 350 53.4 20.4 13.4 9.21 327 43.7 17.9 10.9 7.37 359 65.7 22.2 16.3 10.8

126 07239450 R 269 448 91.7 31.8 21.6 13.6 478 67.6 26.8 15.3 9.54 432 106 35.6 27.1 19.8

127 07239500 U 273 349 107 10.9 0.04 0.02 385 82.0 2.77 0.03 0.02 335 117 24.3 1.17 0.03

R 234 306 59.6 13.5 3.53 0.00 376 48.5 7.98 0.57 0.00 284 70.0 17.2 8.61 1.91

128 07241000 R 187 226 22.8 2.23 0.98 0.09 209 14.1 2.04 0.82 0.00 234 32.5 2.37 1.08 0.10

129 07241500 R 383 398 70.6 34.5 27.8 23.5 523 64.6 34.7 29.4 25.4 344 77.1 34.3 26.3 22.5

130 07241520 R 472 616 197 71.1 44.4 29.6 644 171 59.5 42.3 29.1 600 214 83.2 48.1 29.9131 07241550 R 491 639 222 106 75.7 63.8 614 199 99.7 71.4 59.9 651 239 112 78.9 67.2132 07242000 R 825 1,020 324 113 73.4 52.0 974 285 102 61.3 39.7 1,060 350 120 82.3 61.7133 07242350 UUrb 66.3 51.7 29.0 20.2 14.1 9.40 51.4 28.3 16.5 9.24 6.96 51.9 29.6 21.1 17.1 14.1134 07242380 R 260 294 72.5 29.8 22.3 17.2 267 49.3 22.8 16.8 13.1 310 84.7 41.3 29.0 23.7135 07243000 U 26.2 12.3 2.79 0.12 0.00 0.00 6.25 1.16 0.00 0.00 0.00 16.9 4.53 0.71 0.11 0.00

136 07243500 U 935 1,020 174 43.2 21.1 11.1 695 117 27.4 13.2 5.92 1,290 229 62.1 31.8 19.0137 07244000 U 1,340 1,570 181 42.5 21.4 13.0 1,280 145 32.4 17.6 11.5 1,860 207 56.9 26.0 14.5

138 07245000 U 6,000 7,100 1,620 397 196 106 6,650 1,460 304 138 59.5 7,440 1,720 477 239 149

R 6,130 9,580 3,080 427 120 73.2 6,440 2,750 423 128 82.3 12,100 3,490 431 116 67.1

139 07245500 U 202 215 48.4 6.46 1.67 0.40 70.4 14.8 2.23 0.61 0.20 317 101 21.6 6.32 1.84

140 07247000 U 227 225 36.5 3.13 0.89 0.11 38.7 4.86 0.85 0.18 0.00 372 95.8 21.5 7.83 3.05

141 07247015 U 277 298 49.2 5.91 2.86 1.67 51.6 8.38 2.58 1.50 0.87 524 128 33.5 17.3 8.03
62 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued [Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Annual mean Flow-duration statistics

D20

D50

D80

D90

D95 D20SUM

D50SUM

D80SUM

D90SUM

D95SUM

D20WSP

D50WSP

D80WSP

D90WSP

D95WSP

142 07247250

U 149 166 38.1 1.39 0.05 0.00 30.1 3.35 0.00 0.00 0.00 245 84.7 29.2 12.8 1.31

143 07247500

U 135 116 18.4 1.75 0.26 0.00 28.4 3.78 0.29 0.00 0.00 187 43.5 8.49 2.74 0.72

144 07248500

U 1,310 1,130 215 27.5 4.62 0.65 256 46.2 3.41 0.44 0.04 1,990 512 137 51.3 27.2

R 1,050 1,750 163 11.6 6.36 1.73 316 19.8 7.81 4.18 1.35 3,020 515 71.7 11.8 3.70

145 07249400

U 144 139 29.4 3.78 1.48 0.56 29.5 6.51 1.69 0.68 0.20 218 69.1 18.7 6.09 2.07

146 07249413

R 2,150 4,050 485 49.0 23.8 15.8 1,040 86.8 28.5 18.7 13.8 6,110 1,640 157 57.4 20.9

147 07249500

U 38.4 39.4 6.73 0.78 0.12 0.10 8.05 1.53 0.19 0.10 0.03 59.2 18.9 3.65 1.20 0.30

148 07249985

U 540 654 135 9.96 2.15 0.36 123 19.8 2.16 0.35 0.00 987 331 80.6 27.7 5.38

149 07250000

U 541 635 133 9.68 2.12 0.29 131 19.3 1.99 0.28 0.00 944 316 76.0 26.3 6.33

150 07250550

U 31,600 43,900 13,600 4,980 3,010 1,910 42,100 11,700 4,320 2,560 1,400 0.00 14,900 5,610 3,470 2,320

R 38,800 64,200 22,900 7,130 3,310 1,480 44,300 16,600 5,790 2,540 1,150 77,300 30,400 8,630 4,000 1,860

151 07299200

U 77.4 11.7 1.22 0.25 0.07 0.00 41.9 1.57 0.12 0.03 0.00 3.28 1.14 0.38 0.14 0.05

152 07299300

U 11.3 1.20 0.20 0.08 0.05 0.01 2.86 0.26 0.07 0.01 0.00 0.57 0.18 0.09 0.06 0.04

153 07299540

U 121 68.3 10.2 2.45 1.14 0.52 105 7.95 1.48 0.62 0.25 51.1 11.4 3.47 1.88 1.08

154 07299570

U 149 59.0 8.76 1.66 0.37 0.05 102 6.72 0.38 0.03 0.00 44.2 9.59 2.93 1.51 0.68

155 07299670

U 24.1 19.5 8.26 3.19 1.88 1.07 20.8 8.35 2.76 1.04 0.37 18.7 8.21 3.54 2.26 1.66

156 07299890

U 2.80 3.91 1.86 0.67 0.33 0.03 1.71 0.77 0.25 0.01 0.00 4.55 2.92 1.67 1.28 0.99

157 07300500

U 84.4 68.9 19.2 0.00 0.00 0.00 49.6 3.51 0.00 0.00 0.00 75.1 28.1 6.53 0.07 0.00

158 07301110

U 225 198 74.4 26.8 13.9 8.10 198 71.9 20.3 9.21 6.05 198 75.7 32.9 17.9 11.6

159 07301300

U 36.3 32.3 2.54 0.00 0.00 0.00 5.40 0.00 0.00 0.00 0.00 44.4 11.5 0.16 0.00 0.00

160 07301410

U 13.5 18.0 10.1 2.39 0.80 0.36 10.7 3.00 0.64 0.30 0.14 21.0 13.6 8.49 5.97 4.18

161 07301420

U 24.0 34.3 19.5 5.42 1.74 0.70 22.3 7.38 1.23 0.61 0.30 39.7 24.9 16.4 12.2 8.27

162 07301500

U 130 140 39.3 0.09 0.00 0.00 99.5 8.16 0.00 0.00 0.00 158 60.5 13.2 0.32 0.00

163 07303000

R 57.4 2.57 0.53 0.04 0.00 0.00 1.88 0.36 0.00 0.00 0.00 4.17 0.69 0.11 0.00 0.00
Tables 63

Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued[Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Annual 

mean 

Flow-duration statistics

D20 D50 D80 D90 D95 D20SUM D50SUM D80SUM D90SUM D95SUM D20WSP D50WSP D80WSP D90WSP D95WSP

164 07303400 U 42.0 35.8 17.0 8.84 5.04 2.30 33.7 13.1 4.69 1.96 0.61 37.7 19.8 12.3 9.11 7.00

165 07303500 U 105 71.9 23.7 7.60 3.70 1.38 79.5 20.3 3.91 1.24 0.17 67.5 25.4 11.3 6.53 4.55

166 07304500 U 69.5 42.2 9.84 1.21 0.08 0.00 43.8 8.83 0.22 0.00 0.00 41.4 10.6 2.76 0.56 0.10

R 97.0 48.7 16.4 4.54 1.72 0.62 53.4 13.1 2.18 0.80 0.29 46.7 17.9 7.21 3.87 1.58

167 07305000 R 324 244 64.9 21.3 7.68 2.07 272 64.6 13.1 3.47 0.19 221 65.0 26.1 13.8 5.33

168 07305500 R 11.8 0.12 0.00 0.00 0.00 0.00 0.38 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00

169 07307028 R 540 479 141 63.1 42.0 29.5 553 148 52.1 31.1 18.5 433 138 70.6 51.9 39.2170 07308500 U 1,190 1,110 317 105 53.5 23.4 1,440 321 81.4 32.0 12.2 950 316 120 71.0 42.4

171 07311000 U 183 103 26.2 10.5 6.17 2.43 97.6 23.2 8.17 3.65 0.88 107 29.2 12.5 7.83 4.88

R 246 183 42.3 22.7 17.3 13.7 135 33.0 18.0 13.6 10.6 222 47.5 27.4 21.7 18.0

172 07311200 R 13.4 10.8 1.11 0.00 0.00 0.00 2.95 0.09 0.00 0.00 0.00 15.7 2.77 0.34 0.02 0.00

173 07311500 U 169 42.1 4.91 0.55 0.00 0.00 37.4 3.56 0.07 0.00 0.00 45.1 5.55 1.04 0.25 0.00174 07313000 U 52.3 21.9 7.22 0.20 0.03 0.01 16.2 2.35 0.03 0.02 0.01 24.4 10.9 2.88 0.78 0.03

175 07313500 U 107 55.4 12.9 0.47 0.00 0.00 39.3 4.49 0.00 0.00 0.00 65.3 20.6 2.88 0.11 0.00

R 199 116 1.19 0.00 0.00 0.00 13.7 1.93 0.00 0.00 0.00 213 0.71 0.00 0.00 0.00

176 07315500 R 2,510 2,530 620 276 186 140 2,840 686 264 185 143 2,290 584 285 188 138177 07315700 U 197 76.4 8.70 0.47 0.02 0.00 44.1 4.35 0.14 0.00 0.00 106 13.9 1.24 0.18 0.00

178 07316000 R 3,170 3,260 842 337 219 168 3,490 898 314 207 154 3,060 811 356 229 176179 07316500 U 27.9 30.8 8.32 0.00 0.00 0.00 18.8 1.15 0.00 0.00 0.00 35.1 15.1 2.70 0.00 0.00

180 07319500 U 3.67 3.37 1.28 0.36 0.00 0.00 2.54 0.80 0.14 0.00 0.00 3.83 1.50 0.66 0.20 0.00

181 07323000 U 6.31 6.19 1.94 0.27 0.00 0.00 5.33 1.02 0.07 0.00 0.00 6.67 2.45 0.68 0.20 0.00

182 07324200 U 64.4 79.0 24.5 2.83 0.19 0.00 62.9 13.4 0.76 0.04 0.00 88.2 32.4 8.06 0.56 0.00

183 07324400 R 58.4 23.9 7.61 4.21 2.53 1.06 27.3 7.58 4.26 2.27 0.61 22.3 7.63 4.17 2.68 1.25

184 07325000 U 146 111 25.0 5.88 2.27 0.68 140 27.2 4.58 0.95 0.10 94.9 24.1 7.01 2.92 1.55

R 123 128 33.0 14.6 8.90 5.63 133 28.4 11.4 6.91 4.01 125 35.1 17.4 11.3 7.18
64 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued [Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Annual mean Flow-duration statistics

D20

D50

D80

D90

D95 D20SUM

D50SUM

D80SUM

D90SUM

D95SUM

D20WSP

D50WSP

D80WSP

D90WSP

D95WSP

185 07325500

U 361 377 118 47.3 29.4 19.2 426 110 39.5 24.0 14.2 341 122 53.5 34.7 23.1

186 07325800

U 30.1 27.7 15.7 8.36 5.31 3.68 23.6 10.6 4.94 3.44 2.44 29.7 18.8 12.2 9.74 7.76

187 07326000

U 50.2 43.2 26.2 13.1 8.52 5.68 32.8 15.1 7.76 5.15 2.74 45.6 31.8 21.8 17.4 14.2

R 35.6 5.86 3.18 2.29 1.89 1.65 5.39 2.92 2.10 1.71 1.43 6.18 3.34 2.42 2.09 1.79

188 07326500

R 493 609 185 82.1 56.2 41.1 742 157 64.2 42.6 28.8 552 201 98.6 69.8 54.4

189 07327000

U 14.7 16.3 5.32 0.21 0.03 0.02 10.3 1.19 0.03 0.02 0.01 18.3 7.86 2.85 1.01 0.09

190 073274406

U 1.89 1.69 0.60 0.19 0.08 0.03 1.49 0.36 0.08 0.03 0.00 1.79 0.75 0.28 0.18 0.12

191 07327442

U 4.97 6.23 2.51 0.62 0.37 0.13 5.23 1.18 0.35 0.08 0.02 6.97 3.15 1.18 0.59 0.48

192 07327447

U 23.3 27.4 12.7 4.82 2.89 1.38 23.6 7.67 2.73 1.20 0.69 31.5 14.9 7.71 5.42 4.29

193 07327490

U 38.3 36.0 16.4 5.93 2.50 0.12 27.8 8.45 1.65 0.05 0.02 40.2 21.1 11.3 8.08 5.93

194 07327550

U 60.7 71.0 32.4 10.9 6.28 3.37 58.6 19.6 5.71 2.81 1.58 78.3 40.3 17.7 11.4 9.11

195 07328000

U 670 642 252 126 76.2 51.0 855 255 100 60.1 39.5 552 251 149 96.6 60.2

196 07328070

U 10.8 11.0 4.23 1.61 0.80 0.35 8.12 2.30 0.62 0.29 0.06 11.8 5.56 2.57 1.98 1.48

197 07328100

R 683 894 302 123 79.8 55.7 1,030 249 90.2 56.1 35.1 813 323 147 105 81.8

198 07328180

U 2.70 3.34 0.98 0.16 0.01 0.00 2.41 0.55 0.03 0.00 0.00 3.88 1.31 0.38 0.10 0.02

199 07328500

U 828 874 306 130 76.7 45.6 1,020 325 111 54.1 22.9 763 298 140 91.7 63.6

R 954 1,210 414 154 94.4 60.7 1,270 350 112 61.1 29.3 1,180 445 190 128 94.8

200 07329000

U 80.0 59.3 20.2 7.30 3.51 0.78 42.4 12.8 4.08 1.82 0.34 69.4 25.7 12.4 7.23 4.02

201 07329500

U 51.6 36.9 13.6 2.68 0.09 0.00 31.2 7.73 0.00 0.00 0.00 40.3 17.9 6.08 2.74 1.19

202 07329700

R 265 245 47.6 10.7 4.00 1.74 139 26.5 4.41 1.49 0.53 300 71.8 19.1 9.39 5.06

203 07329852

U 55.4 47.4 18.2 8.13 5.80 4.18 26.7 12.9 6.94 5.03 2.72 60.0 25.3 10.0 6.85 4.87

204 07329900

U 63.6 52.4 18.3 7.40 5.16 3.89 25.6 11.4 5.15 3.68 2.33 66.8 27.8 9.86 7.35 6.00

205 07330500

U 154 83.3 15.9 1.20 0.04 0.02 47.6 4.48 0.13 0.03 0.01 110 25.8 4.68 0.91 0.04
Tables 65

Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued[Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Annual 

mean 

Flow-duration statistics

D20 D50 D80 D90 D95 D20SUM D50SUM D80SUM D90SUM D95SUM D20WSP D50WSP D80WSP D90WSP D95WSP

206 07331000 U 1,540 1,530 509 218 138 84.6 1,640 486 180 104 51.7 1,480 519 247 165 115

R 1,900 2,360 705 237 142 84.9 2,090 535 162 83.6 41.7 2,550 815 304 209 148

207 07331600 U 5,680 6,380 2,100 816 553 393 7,090 2,120 739 504 359 5,920 2,090 859 595 434

R 4,880 5,790 2,770 756 188 96.1 5,740 2,990 1,080 220 108 5,840 2,600 642 162 91.0

208 07332400 U 142 145 66.4 38.4 31.4 28.2 102 50.8 35.3 30.4 28.0 171 85.3 44.4 32.6 28.4

209 07332500 U 322 258 89.4 38.2 28.0 20.6 153 57.7 29.9 20.9 12.8 339 120 50.8 35.3 28.5

210 07332600 U 54.8 28.4 4.78 0.03 0.00 0.00 7.07 0.31 0.00 0.00 0.00 40.9 11.5 1.72 0.12 0.01

211 07333500 U 30.4 11.7 1.23 0.00 0.00 0.00 2.50 0.24 0.00 0.00 0.00 20.3 3.63 0.24 0.00 0.00

212 07333800 U 86.7 41.3 4.75 0.09 0.00 0.00 10.3 1.13 0.00 0.00 0.00 71.5 11.8 1.50 0.18 0.00

213 07334000 U 880 594 73.0 9.04 2.16 0.49 198 23.9 2.58 0.54 0.00 964 152 27.6 10.6 3.57

R 947 1,250 109 26.6 18.7 15.1 356 39.2 18.4 14.7 12.7 1,840 275 45.5 29.3 23.3

214 07335000 U 488 401 80.9 18.8 10.3 5.47 180 36.1 11.8 5.57 1.40 571 132 37.2 17.1 11.0

215 07335300 R 2,130 2,930 433 106 59.3 35.0 1,020 176 62.4 34.9 22.1 4,510 845 200 112 73.9216 07335400 R 134 220 25.2 0.00 0.00 0.00 103 0.00 0.00 0.00 0.00 283 74.4 0.00 0.00 0.00

217 07335500 R 9,190 13,000 4,230 2,040 1,320 894 9,500 3,790 2,010 1,320 848 14,800 4,800 2,060 1,330 924218 07335700 U 82.9 101 26.0 1.23 0.01 0.00 20.8 1.98 0.00 0.00 0.00 140 52.7 19.1 9.36 3.46

219 07335790 R 1,030 1,720 218 11.5 2.82 0.44 346 21.1 2.77 0.62 0.00 2,460 584 117 44.5 10.6

220 07336000 U 76.4 44.8 5.67 0.08 0.00 0.00 9.25 0.68 0.00 0.00 0.00 74.3 15.5 2.01 0.35 0.00

221 07336200 U 1,480 1,610 332 45.8 13.7 1.97 447 65.8 10.8 1.21 0.00 2,360 677 200 110 69.8

R 1,610 2,510 345 26.4 6.44 1.88 538 51.2 6.76 2.18 0.00 3,690 877 191 72.6 12.2

222 07336500 U 1,700 1,670 343 39.3 9.38 1.40 436 70.3 8.48 0.93 0.04 2,580 727 206 86.3 32.7

223 07336750 U 77.3 29.6 1.58 0.00 0.00 0.00 1.39 0.00 0.00 0.00 0.00 64.0 8.12 0.37 0.00 0.00

224 07336800 U 82.1 31.8 1.31 0.00 0.00 0.00 1.76 0.00 0.00 0.00 0.00 81.1 8.81 0.29 0.00 0.00

225 07336820 R 14,400 23,600 6,740 2,930 2,000 1,470 14,500 4,720 2,480 1,750 1,280 27,800 9,260 3,510 2,330 1,650
66 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 2. Annual, summer-autumn, and winter-spring flow-duration statistics and annual mean-flow statistics for selected streamflow-gaging stations and periods of record. —Continued [Map no.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; Annual Mean, mean of daily flows; Dxx, annual flow exceedance which is the daily mean discharge that is equaled or exceeded xx percent of the time during the specified time period, in cubic feet per second; DxxSUM, daily mean discharge for the summer-autumn period (June 1 to October 31) exceeded xx percent of the time, in cubic feet per second; DxxWSP, daily mean discharge for the winter-spring period (November 1 to May 31) exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Annual mean Flow-duration statistics

D20

D50

D80

D90

D95 D20SUM

D50SUM

D80SUM

D90SUM

D95SUM

D20WSP

D50WSP

D80WSP

D90WSP

D95WSP

226 07337500

U 907 947 203 21.5 3.52 0.90 211 37.7 3.03 0.78 0.05 1,500 448 131 55.1 18.0

R 902 1,320 182 26.6 16.9 11.8 274 41.5 17.3 12.1 8.49 2,090 430 61.3 30.5 20.0

227 07337900

U 492 526 122 11.6 3.29 1.11 144 18.6 3.15 0.99 0.19 752 253 76.4 35.6 15.0

228 07338500

U 1,630 1,860 398 52.2 18.0 7.65 388 81.1 16.5 6.92 3.12 3,120 894 271 126 51.5

R 1,810 3,530 530 81.6 44.0 31.7 873 123 43.1 31.2 23.3 4,860 1,290 269 129 75.2

229 07338750

U 556 650 186 19.8 7.43 3.86 184 30.1 6.53 3.13 1.89 907 355 139 81.4 39.7

230 07339000

U 1,290 1,490 343 43.8 11.7 1.94 325 67.5 9.97 1.53 0.04 2,360 732 236 115 55.1

R 1,400 2,290 615 209 150 121 1,240 480 217 169 141 3,140 863 201 136 113

231 07339500

U 288 286 60.0 6.70 2.48 0.87 58.1 9.75 2.45 0.88 0.33 475 139 39.4 17.3 7.19

232 07340300

U 185 193 62.5 20.1 14.3 11.9 59.7 22.5 13.8 11.4 9.84 281 109 51.1 33.7 24.2

233 07340500

U 619 674 153 28.7 15.8 9.62 150 37.1 14.4 8.84 5.81 1,040 330 109 59.4 35.7

234 07341000

U 194 215 44.1 4.16 0.89 0.19 40.0 6.50 0.65 0.18 0.08 342 106 29.2 12.6 6.01

235 07341200

U 374 322 61.6 5.43 2.03 1.03 70.3 9.93 1.91 1.00 0.72 514 151 35.6 13.3 4.75
Tables 67

Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Monthly flow-duration statistics

OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95

1 07146500 U 976 343 189 140 93.3 1,050 491 231 169 134 856 443 260 196 82.2

R 2,080 877 330 240 184 1,670 890 438 340 262 1,460 848 449 345 278

2 07148140 R 1,820 346 148 125 48.4 4,270 682 154 133 122 2,450 752 292 159 138

3 07148350 U 51.1 7.29 0.22 0.04 0.00 68.3 30.8 0.84 0.29 0.13 66.5 37.4 11.6 2.88 0.39

4 07148400 U 95.3 17.4 2.24 0.71 0.03 105 36.5 8.53 0.95 0.03 95.7 44.5 19.8 3.96 1.22

5 07149000 U 132 60.1 19.4 6.33 0.00 141 89.0 56.7 40.9 23.5 134 96.0 61.7 44.0 30.8

6 07149500 U 320 53.4 4.26 0.03 0.01 218 107 33.0 14.6 0.04 211 123 51.1 42.8 37.0

7 07150500 R 360 28.6 7.74 4.08 3.11 373 102 4.66 2.14 1.30 298 120 11.3 1.65 1.11

8 07151000 R 717 119 43.9 24.4 17.3 773 214 45.1 26.4 17.6 580 223 62.4 31.9 17.4

9 07151500 U 161 66.1 27.8 10.9 0.92 209 96.3 49.2 35.3 17.9 163 99.9 53.2 37.7 19.1

10 07152000 U 273 95.9 27.0 7.66 4.12 327 142 56.8 30.5 9.37 297 143 69.6 44.6 22.9

11 07152500 U 4,330 1,440 489 317 213 4,030 1,680 521 339 232 3,140 1,510 667 415 247

R 5,140 1,090 409 261 177 7,000 1,720 532 392 218 5,380 1,630 584 404 325

12 07153000 U 46.4 7.31 0.98 0.14 0.00 61.9 12.1 1.95 0.62 0.00 47.7 12.6 3.08 1.12 0.00

13 07153100 R 0.05 0.03 0.01 0.01 0.00 0.05 0.03 0.01 0.01 0.00 0.10 0.03 0.01 0.01 0.00

14 07154500 U 3.28 1.13 0.11 0.03 0.01 3.33 1.73 0.88 0.33 0.03 3.37 1.80 0.88 0.61 0.04

UI 1.04 0.00 0.00 0.00 0.00 1.99 0.28 0.00 0.00 0.00 2.54 0.75 0.00 0.00 0.00

15 07155000 U 1.64 0.03 0.01 0.01 0.00 13.1 0.05 0.02 0.01 0.00 10.9 5.30 0.03 0.01 0.01

16 07155590 U 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00

17 07156900 U 88.8 65.9 50.0 43.6 39.2 89.9 71.7 58.2 53.7 49.6 90.8 70.4 59.3 53.5 48.9

UI 36.3 31.7 28.1 26.3 25.1 42.9 37.1 31.7 29.7 28.6 45.5 39.0 32.9 29.8 27.2

18 07157000 U 78.9 55.0 40.9 36.3 32.1 96.7 66.4 48.6 41.6 37.3 98.6 65.6 44.1 36.2 25.6

19 07157500 U 19.9 9.69 3.73 0.31 0.03 19.8 13.4 8.95 6.91 4.79 23.3 15.8 10.1 7.64 6.32

UI 9.61 5.81 4.01 3.13 2.26 12.1 7.99 5.59 4.73 4.15 12.2 8.69 6.56 5.54 5.04
68 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Monthly flow-duration statistics OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95 20 07157900

U 1.94 1.22 0.67 0.49 0.36 2.28 1.60 1.07 0.74 0.58 2.58 1.70 1.11 0.79 0.59

21 07157950

U 75.5 5.56 0.01 0.00 0.00 110 51.0 6.10 0.63 0.30 122 63.8 25.3 12.3 5.98

22 07157960

U 8.47 0.15 0.00 0.00 0.00 11.2 1.27 0.04 0.00 0.00 8.93 1.82 0.74 0.13 0.00

23 07158000

U 156 17.4 0.18 0.00 0.00 180 70.0 7.33 1.06 0.00 189 94.6 31.0 12.2 3.10

24 07158400

U 12.7 6.73 3.11 1.80 1.51 33.2 7.40 5.05 3.47 2.07 19.5 8.15 5.14 3.65 2.90

25 07159000

U 5.47 0.79 0.00 0.00 0.00 7.87 1.31 0.24 0.00 0.00 7.28 2.03 0.41 0.23 0.09

26 07159100

U 574 130 51.9 39.8 30.6 636 195 79.1 55.6 43.0 552 259 115 78.7 60.4

27 07159750

U 81.4 42.6 23.7 15.2 12.8 118 57.4 29.1 18.4 15.2 109 61.5 27.0 20.0 17.9

28 07160000

U 1,100 368 151 102 75.0 1,270 508 218 151 85.3 1,010 571 297 199 141

29 07160350

U 18.3 10.0 5.08 3.99 3.18 19.6 13.2 7.10 5.71 4.84 18.6 13.2 7.21 5.49 4.30

30 07160500

U 37.9 11.2 4.50 2.90 1.07 44.3 14.2 6.33 3.66 2.26 43.2 14.3 7.06 4.93 3.64

31 07163000

U 1.44 0.00 0.00 0.00 0.00 2.62 0.25 0.00 0.00 0.00 2.43 0.39 0.00 0.00 0.00

32 07163500

U 1,250 253 91.3 54.5 15.6 744 190 61.0 30.5 14.2 564 215 76.1 48.2 15.4

33 07164000

U 1,860 478 96.4 59.5 32.5 1,170 405 124 48.0 21.3 872 391 195 79.2 25.6

34 07164500

U 5,950 2,160 692 391 287 4,460 2,130 654 430 283 3,670 1,930 808 557 293

R 7,880 2,370 623 292 178 9,780 2,660 920 408 206 7,950 2,650 847 354 183

35 07164600 UUrb 4.23 1.82 1.05 0.83 0.71 7.07 2.63 1.47 1.14 0.92 8.52 3.13 1.43 1.11 0.91

36 07165500

R 8.83 0.29 0.00 0.00 0.00 11.6 0.37 0.00 0.00 0.00 12.0 0.39 0.00 0.00 0.00

37 07165562 UUrb 3.55 0.29 0.00 0.00 0.00 9.68 1.74 0.51 0.16 0.00 9.04 2.44 0.96 0.47 0.22

38 07165565 UUrb 2.14 0.22 0.01 0.00 0.00 4.49 0.76 0.20 0.07 0.02 3.90 0.95 0.31 0.17 0.09

39 07165570

R 10,100 2,420 801 574 435 12,700 3,290 1,010 635 449 10,400 3,150 1,130 708 505

40 07170500

U 474 47.5 12.8 6.28 2.88 589 77.5 9.61 2.34 0.31 634 125 20.2 10.3 6.03

R 1,150 107 31.3 22.3 17.5 3,160 168 40.6 29.4 23.8 2,170 446 54.3 35.4 26.6

41 07170700

U 3.72 0.27 0.00 0.00 0.00 12.0 1.42 0.00 0.00 0.00 9.36 1.72 0.10 0.00 0.00

R 6.09 0.03 0.00 0.00 0.00 16.2 0.12 0.00 0.00 0.00 21.4 0.51 0.01 0.00 0.00
Tables 69

Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Monthly flow-duration statistics

OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95

42 07171000 U 886 60.7 9.18 4.79 0.05 609 79.8 11.4 6.30 1.81 543 115 15.7 7.43 2.40

R 1,470 147 37.0 21.1 13.5 3,730 273 50.1 30.1 21.1 2,760 603 67.5 40.8 29.9

43 07171400 R 1,900 72.8 8.43 4.43 2.18 4,380 94.1 9.03 4.57 2.77 3,880 510 14.8 6.81 1.66

44 07172000 U 110 6.74 0.00 0.00 0.00 174 26.5 0.24 0.00 0.00 186 32.9 2.67 0.20 0.00

45 07173000 U 145 17.3 7.35 2.24 0.61 220 18.3 8.52 3.49 1.52 304 25.4 9.53 4.88 2.18

46 07174200 U 56.6 3.54 0.08 0.00 0.00 96.6 6.51 0.34 0.07 0.00 80.0 12.3 0.56 0.11 0.07

47 07174400 R 386 37.9 22.7 15.1 11.0 1,510 49.6 26.8 15.8 10.2 1,570 112 22.7 8.38 4.74

48 07174600 U 18.8 1.78 0.00 0.00 0.00 47.9 7.28 0.18 0.00 0.00 47.1 10.3 2.31 0.00 0.00

49 07174700 R 480 46.6 14.5 10.8 6.96 1,330 65.0 20.3 13.9 11.4 1,180 114 22.0 14.9 11.1

50 07175000 U 0.24 0.00 0.00 0.00 0.00 0.64 0.00 0.00 0.00 0.00 0.92 0.00 0.00 0.00 0.00

51 07175500 R 1,000 71.6 36.6 26.8 20.9 2,060 131 44.0 29.2 18.2 2,020 282 52.2 26.5 15.8

52 07176000 U 2,520 209 15.7 5.49 0.03 2,240 244 20.9 6.60 0.04 1,460 236 35.7 15.1 8.80

R 2,460 148 54.6 34.2 20.7 8,300 289 60.4 36.2 20.6 6,970 782 69.7 45.2 36.0

53 07176465 R 13.5 5.08 2.46 1.53 0.99 7.74 3.92 1.67 1.04 0.06 17.9 3.65 1.46 0.99 0.11

54 07176500 U 54.1 2.87 0.00 0.00 0.00 72.1 5.30 0.00 0.00 0.00 83.1 6.93 0.18 0.00 0.00

R 62.5 23.2 7.90 5.11 3.87 194 25.3 10.3 6.30 4.46 139 33.6 9.61 6.00 4.48

55 07176800 U 5.27 0.49 0.00 0.00 0.00 10.5 0.73 0.00 0.00 0.00 8.72 0.74 0.10 0.00 0.00

56 07177000 U 26.8 2.38 0.24 0.00 0.00 40.6 4.92 0.40 0.09 0.00 31.8 5.08 1.06 0.11 0.00

57 07177500 U 112 11.6 2.13 0.65 0.04 155 23.2 3.67 1.10 0.48 140 26.3 5.66 2.22 0.47

R 249 157 64.9 50.9 26.3 669 84.7 57.7 50.9 42.0 417 103 67.7 57.2 51.7

58 07177650 UUrb 0.88 0.20 0.04 0.01 0.00 2.51 0.57 0.07 0.02 0.00 3.47 1.01 0.13 0.06 0.03

59 07177800 UUrb 3.74 1.23 0.42 0.29 0.19 6.02 2.25 0.70 0.36 0.22 6.79 2.82 1.28 0.75 0.47

60 07178000 R 269 174 87.5 72.8 67.4 576 119 78.8 71.0 67.2 459 130 84.0 73.9 69.3

61 07178040 UUrb 21.8 4.49 2.32 1.74 1.40 65.2 14.6 4.05 3.05 2.38 55.3 19.9 6.57 3.44 2.60

62 07178200 R 430 236 139 109 96.6 828 192 113 99.5 91.9 589 220 137 114 101
70 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Monthly flow-duration statistics OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95 63 07178600

U 2,720 245 54.6 30.4 18.1 1,500 322 62.5 40.8 34.0 1,400 264 83.0 44.0 33.0

64 07184000

U 32.3 2.65 0.00 0.00 0.00 72.6 7.75 0.00 0.00 0.00 62.1 13.8 1.25 0.00 0.00

65 07185000

U 2,840 420 37.5 2.13 0.22 1,850 306 15.4 3.91 1.61 1,440 318 29.4 10.4 6.37

R 2,500 207 50.5 27.5 18.2 4,880 453 64.2 38.2 27.4 3,500 776 86.6 58.0 42.1

66 07185095 UUrb 14.6 4.27 1.70 1.02 0.48 64.2 12.8 3.46 1.47 0.83 44.8 14.6 4.45 2.42 0.97

67 07185500

U 1.85 0.22 0.00 0.00 0.00 2.57 0.28 0.00 0.00 0.00 2.94 0.43 0.00 0.00 0.00

68 07185700

U 190 89.2 54.0 35.6 31.6 305 81.3 53.9 43.9 37.4 285 109 51.5 44.5 34.8

69 07185765

U 230 112 60.2 40.4 29.9 512 128 64.0 55.1 45.8 528 213 81.6 56.7 47.4

70 07186000

U 490 144 64.4 44.8 34.5 811 172 74.9 55.5 46.0 824 257 80.9 58.0 47.8

71 07186400

U 141 53.2 34.0 27.5 20.3 268 71.8 36.9 30.9 27.6 303 112 37.5 30.3 25.9

72 07187000

U 316 141 86.5 68.4 54.5 455 151 94.7 76.0 64.9 454 203 102 76.9 67.9

73 07187500

U 348 161 82.5 65.1 57.6 342 176 93.6 74.1 62.6 404 183 98.1 80.1 69.7

74 07188000

U 1,310 420 208 143 107 2,270 496 248 184 138 2,090 720 266 196 150

75 07188500

U 18.8 9.69 4.86 3.18 1.46 15.2 8.15 5.44 3.30 2.77 12.7 6.99 4.79 4.01 3.55

76 07189000

U 396 137 77.4 59.8 48.4 829 227 100 78.3 67.2 878 362 133 88.5 68.7

77 07189500

U 3,660 1,300 684 450 348 4,220 1,580 650 463 411 4,690 2,030 699 474 381

78 07189540

U 3.62 2.82 2.18 1.95 1.73 4.09 3.07 2.39 2.03 1.70 4.29 3.24 2.55 2.33 2.12

79 07189542

U 16.3 11.7 7.35 6.04 5.37 25.6 14.1 10.2 8.10 7.30 36.8 19.7 12.8 9.86 8.81

80 07190500

R 8,020 1,890 89.0 30.9 26.1 11,400 2,400 154 50.2 27.5 9,680 2,750 331 73.6 28.9

81 07191000

U 64.4 5.34 1.50 0.95 0.61 184 15.6 2.43 1.61 1.07 175 34.4 2.90 1.83 1.51

82 07191220

U 62.0 26.2 14.3 10.1 6.78 120 41.7 20.0 13.8 10.8 141 66.1 24.4 15.5 11.7

83 07191500

R 8,700 1,100 211 163 134 14,600 2,430 287 187 152 12,800 4,330 360 212 170

84 07192000

U 24.6 0.30 0.03 0.01 0.01 17.8 0.74 0.03 0.02 0.01 20.7 0.98 0.03 0.02 0.01

85 07192500

R 7,930 3,230 380 188 116 6,520 3,040 1,250 338 258 5,710 2,420 1,100 468 354
Tables 71

Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Monthly flow-duration statistics

OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95

86 07193500 R 11,500 1,800 181 30.7 15.6 14,100 3,050 362 56.6 16.6 12,600 3,580 479 89.2 32.0

87 07194500 U 17,900 5,670 2,440 1,450 896 16,000 5,930 2,280 1,260 892 13,200 5,850 2,730 1,460 1,040

R 14,400 4,900 2,030 1,030 643 19,800 5,900 1,870 1,020 301 17,000 6,910 2,280 1,640 820

88 07194800 U 48.7 16.3 9.54 6.96 5.75 178 36.8 14.5 11.3 9.98 196 68.3 18.3 10.4 8.70

89 07195000 U 89.7 60.9 31.0 24.3 19.7 135 69.4 33.5 25.9 22.8 137 74.0 34.9 26.0 22.8

90 07195430 U 240 172 134 115 107 497 226 155 125 112 632 342 216 136 112

91 07195500 U 338 167 106 73.7 54.5 725 238 125 92.0 68.1 773 334 140 103 75.9

92 07195800 U 12.2 6.37 3.74 2.76 2.26 21.0 9.13 5.47 3.67 3.06 20.7 10.0 5.30 3.85 3.23

93 07195855 R 25.0 13.2 7.60 5.83 3.83 61.9 23.8 12.6 8.59 6.07 65.6 32.7 14.2 11.3 8.01

94 07195865 U 9.20 6.66 5.33 4.66 4.32 19.8 9.48 6.03 5.12 4.62 22.4 14.0 8.47 6.51 5.69

95 07196000 U 73.2 30.4 19.9 14.5 11.4 135 49.8 23.0 17.2 13.3 133 63.0 29.2 21.2 15.8

96 07196500 U 541 216 117 85.5 64.1 1,080 304 161 109 87.6 1,080 424 179 127 101

97 07196900 U 17.5 2.90 0.80 0.41 0.28 53.7 13.2 2.54 1.08 0.73 61.9 20.8 4.14 2.43 1.14

98 07196973 U 9.43 2.98 0.18 0.00 0.00 43.7 8.46 2.59 1.20 0.81 41.1 19.3 7.16 3.33 2.51

99 07197000 U 124 48.9 21.1 12.1 6.68 355 82.5 33.9 19.9 14.8 405 140 38.8 26.3 18.9

100 07197360 U 32.6 15.5 10.5 8.23 7.41 75.0 34.6 15.7 11.4 9.85 107 57.5 26.0 11.0 8.23

101 07198000 U 760 332 185 137 87.3 1,940 386 235 193 169 1,480 467 256 215 185

R 1,050 239 79.9 52.2 38.0 1,920 416 77.5 55.6 46.4 2,610 813 123 63.1 50.8

102 07228500 U 205 32.8 7.66 3.55 2.29 118 32.6 14.0 9.95 8.04 114 34.7 19.7 14.4 11.1

R 178 32.9 15.9 10.4 7.04 251 88.5 29.6 19.4 16.1 326 122 61.8 32.2 22.9

103 07229100 R 142 41.8 6.50 5.33 4.74 332 65.0 27.8 15.3 5.82 270 105 36.4 20.5 13.8

104 07229200 R 447 137 36.1 12.5 3.18 654 239 101 43.0 21.4 778 334 152 94.2 62.7

105 07229300 U 44.4 14.8 3.78 0.61 0.34 54.5 22.7 7.15 3.52 1.89 57.0 20.7 7.58 4.75 4.00

106 07230000 U 20.0 5.32 0.68 0.15 0.03 27.4 5.67 1.11 0.44 0.34 27.4 7.38 2.05 1.07 0.64

R 0.93 0.61 0.40 0.20 0.15 0.94 0.59 0.35 0.20 0.16 0.93 0.60 0.39 0.23 0.16
72 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Monthly flow-duration statistics OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95 107 07230500

U 36.7 8.32 2.41 0.05 0.02 48.8 16.0 4.52 1.36 0.42 52.1 21.3 7.42 3.18 1.80

R 33.5 8.62 1.98 0.45 0.00 72.0 16.1 4.28 2.53 1.84 55.1 19.8 6.13 3.44 2.64

108 07231000

U 112 20.2 5.11 1.62 0.13 112 37.0 10.7 5.29 3.49 108 44.8 17.4 10.9 5.90

R 111 18.7 0.62 0.09 0.00 286 36.0 5.58 0.67 0.02 196 47.3 11.5 2.58 0.33

109 07231500

U 831 141 14.4 1.19 0.25 644 184 37.3 11.4 4.65 867 206 53.0 23.2 12.8

R 845 209 27.0 9.88 4.38 1,540 414 76.8 36.9 15.1 1,370 486 138 56.0 32.5

110 07232000

U 56.8 6.97 0.13 0.03 0.01 115 9.04 0.89 0.04 0.02 160 30.1 7.37 1.31 0.13

111 07232500

U 6.81 2.50 1.07 0.69 0.23 9.46 5.84 2.68 1.44 1.07 10.3 6.92 4.58 3.40 2.35

UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.32 0.00 0.00 0.00 0.00

112 07232900 UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

113 07233000

U 2.24 0.04 0.01 0.01 0.00 5.16 2.34 0.03 0.01 0.01 5.72 3.62 0.52 0.03 0.01

114 07233500

U 3.29 0.44 0.00 0.00 0.00 2.70 1.03 0.21 0.00 0.00 2.23 0.89 0.33 0.20 0.00

115 07233650

R 0.76 0.28 0.04 0.00 0.00 1.12 0.77 0.46 0.35 0.21 1.26 0.99 0.69 0.52 0.45

116 07234000 RI 2.72 0.05 0.00 0.00 0.00 5.65 0.19 0.00 0.00 0.00 5.51 0.24 0.02 0.00 0.00

U 19.7 0.01 0.00 0.00 0.00 25.6 2.16 0.00 0.00 0.00 32.2 13.4 0.00 0.00 0.00

117 07234100

U 2.52 1.79 1.25 1.02 0.88 3.20 2.34 1.80 1.60 1.49 3.20 2.47 1.94 1.70 1.58

118 07234500

U 120 4.12 0.03 0.01 0.01 71.4 4.83 0.02 0.01 0.01 87.0 10.5 0.04 0.02 0.01

119 07235000

R 5.11 2.71 0.66 0.31 0.10 12.2 4.34 2.38 1.01 0.00 9.12 5.55 3.55 2.88 2.33

RI 1.99 0.96 0.52 0.41 0.35 2.62 1.34 0.71 0.57 0.48 3.51 2.19 0.90 0.69 0.56

120 07236000

U 63.9 15.3 0.04 0.02 0.01 49.1 29.7 3.55 0.64 0.03 55.3 33.4 16.7 7.27 2.68

121 07237000

R 18.4 1.34 0.56 0.14 0.03 32.4 2.35 1.03 0.72 0.18 48.7 21.8 1.02 0.54 0.35

RI 29.8 1.70 0.80 0.68 0.60 46.8 2.67 1.27 0.99 0.85 51.5 15.5 1.41 1.22 0.99

122 07237500

U 105 5.62 0.00 0.00 0.00 76.7 14.4 0.00 0.00 0.00 101 30.8 1.09 0.00 0.00

RI 69.6 13.2 4.77 3.33 2.52 108 30.9 8.27 5.81 4.84 105 41.7 12.3 8.27 6.34

123 07238000

U 86.3 10.2 0.00 0.00 0.00 97.0 26.5 0.00 0.00 0.00 113 48.1 0.00 0.00 0.00

RI 134 35.4 7.56 2.69 0.89 172 57.6 23.0 15.6 11.0 171 74.8 37.5 27.6 21.9
Tables 73

Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Monthly flow-duration statistics

OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95

124 07239000 U 549 39.0 0.03 0.02 0.01 256 16.2 0.04 0.02 0.01 213 22.2 0.04 0.02 0.01

R 29.9 9.39 3.58 2.14 1.16 75.2 9.27 3.80 2.60 1.93 92.8 9.48 3.72 2.74 2.15

125 07239300 R 85.3 28.8 15.1 10.5 6.94 161 35.3 18.2 9.49 7.74 222 40.7 18.4 11.5 9.42

126 07239450 R 162 40.9 23.7 15.1 5.05 211 54.3 28.4 19.3 6.56 243 79.6 31.1 18.4 13.1

127 07239500 U 376 47.5 0.50 0.03 0.01 276 41.9 1.64 0.04 0.02 254 73.3 2.12 0.04 0.02

R 150 36.0 4.14 0.00 0.00 160 42.3 12.8 3.40 0.33 160 41.4 13.7 7.01 1.35

128 07241000 R 107 13.9 2.17 1.10 0.00 119 23.4 2.38 1.17 0.00 156 24.8 2.24 1.18 0.07

129 07241500 R 619 52.8 30.0 25.0 21.4 182 51.9 29.3 24.9 22.5 271 48.1 30.2 22.7 19.3

130 07241520 R 389 98.0 60.4 42.5 36.0 354 132 74.7 45.2 31.1 420 178 74.4 54.1 33.8

131 07241550 R 430 178 86.9 65.0 55.3 481 192 99.1 72.4 61.1 433 197 98.7 75.6 67.3

132 07242000 R 691 220 78.6 48.4 23.6 722 245 96.4 64.4 43.9 671 236 95.7 70.7 56.2

133 07242350 UUrb 40.1 25.3 18.1 11.4 8.56 43.4 25.7 20.4 15.4 9.63 37.5 25.6 20.2 16.0 11.3

134 07242380 R 140 44.2 23.2 18.1 15.1 254 69.0 31.0 25.0 22.2 184 72.7 37.3 24.5 20.0

135 07243000 U 4.81 0.41 0.00 0.00 0.00 7.57 1.95 0.11 0.00 0.00 11.7 2.53 0.38 0.00 0.00

136 07243500 U 401 78.1 16.5 7.12 1.20 665 107 25.5 15.3 4.52 520 120 39.5 23.6 12.3

137 07244000 U 555 65.6 14.7 9.32 5.88 372 80.6 22.4 14.9 11.1 324 89.1 35.9 12.0 7.49

138 07245000 U 4,040 789 188 71.9 22.6 3,010 734 226 110 52.2 3,040 808 262 160 101

R 3,890 931 107 66.9 48.7 8,760 2,070 214 86.0 53.2 9,620 1,970 282 90.4 64.2

139 07245500 U 54.7 10.1 1.08 0.28 0.11 159 22.5 1.91 0.46 0.04 164 41.4 6.78 1.98 1.17

140 07247000 U 31.2 3.37 0.34 0.00 0.00 154 20.6 3.33 0.77 0.00 343 68.9 10.3 3.12 1.60

141 07247015 U 50.5 9.52 2.34 1.35 0.64 397 50.1 11.0 4.58 3.15 646 170 34.4 7.62 4.51

142 07247250 U 24.8 1.95 0.00 0.00 0.00 198 34.1 1.08 0.27 0.00 276 101 23.8 1.07 0.51

143 07247500 U 26.6 2.55 0.09 0.00 0.00 96.0 10.7 0.89 0.11 0.00 127 23.9 3.19 0.67 0.19

144 07248500 U 210 8.15 0.05 0.03 0.01 641 154 20.1 8.53 1.70 905 248 53.0 29.8 21.6

R 235 13.5 5.74 1.92 0.52 845 50.9 5.82 1.93 0.56 2,350 412 26.0 1.35 0.31
74 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Monthly flow-duration statistics OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95 145 07249400

U 26.4 4.72 1.20 0.61 0.09 116 23.2 3.51 1.79 0.50 199 54.1 11.9 3.17 0.58

146 07249413

R 485 53.5 20.8 13.7 10.7 2,520 154 41.3 20.0 13.7 6,630 1,860 63.7 14.1 9.33

147 07249500

U 6.05 1.68 0.10 0.04 0.02 19.2 2.63 0.11 0.09 0.03 23.5 6.17 1.28 0.35 0.12

148 07249985

U 135 21.6 0.89 0.08 0.00 576 85.6 5.64 0.63 0.04 664 203 34.6 9.12 3.01

149 07250000

U 175 20.6 0.83 0.02 0.00 502 76.9 5.50 0.44 0.05 610 173 32.5 9.92 3.74

150 07250550

U 44,900 13,800 4,940 2,960 1,870 26,300 7,800 3,100 1,810 1,410 22,600 8,570 3,610 2,370 1,560

R 31,700 9,650 2,550 1,130 283 59,300 16,700 4,080 1,620 330 57,800 18,800 5,660 2,760 1,440

151 07299200

U 3.60 0.88 0.19 0.05 0.01 3.70 1.13 0.27 0.09 0.04 2.39 1.18 0.51 0.29 0.19

152 07299300

U 1.19 0.18 0.07 0.04 0.03 0.56 0.18 0.10 0.07 0.06 0.47 0.20 0.12 0.09 0.06

153 07299540

U 50.3 7.03 2.23 1.33 0.83 40.9 10.2 3.30 1.75 0.82 38.7 9.19 4.05 2.40 1.52

154 07299570

U 36.8 4.49 1.01 0.38 0.13 42.4 9.30 2.33 1.18 0.61 33.5 9.53 4.97 3.20 1.47

155 07299670

U 21.0 9.31 3.21 1.93 0.95 19.3 9.08 3.67 2.65 1.72 16.7 8.23 3.41 2.35 1.79

156 07299890

U 1.96 1.09 0.75 0.62 0.49 3.53 1.82 1.30 1.17 1.08 4.20 2.86 1.79 1.58 1.40

157 07300500

U 32.6 4.27 0.00 0.00 0.00 46.3 16.2 0.26 0.00 0.00 56.6 24.0 8.02 0.56 0.00

158 07301110

U 138 29.8 8.84 6.65 4.41 139 52.2 14.8 8.32 6.75 140 60.1 24.0 16.4 13.3

159 07301300

U 5.95 0.00 0.00 0.00 0.00 20.6 3.37 0.00 0.00 0.00 32.7 12.0 1.26 0.00 0.00

160 07301410

U 10.5 3.45 0.99 0.56 0.34 14.7 9.15 3.87 2.20 1.43 16.6 11.7 6.88 4.80 3.88

161 07301420

U 23.2 7.62 2.50 0.69 0.32 31.1 17.7 7.95 5.30 3.96 33.0 21.9 14.3 9.13 6.87

162 07301500

U 55.1 5.01 0.00 0.00 0.00 96.2 23.4 0.22 0.00 0.00 116 42.9 3.62 0.00 0.00

163 07303000

R 1.18 0.25 0.00 0.00 0.00 1.95 0.56 0.12 0.00 0.00 2.74 0.74 0.14 0.05 0.00

164 07303400

U 29.3 14.2 7.02 4.60 3.41 38.9 18.5 10.9 8.23 6.50 30.7 18.5 12.2 9.48 8.00

165 07303500

U 79.2 20.2 6.08 1.94 0.28 68.6 23.3 8.60 4.64 3.75 50.4 23.6 11.1 7.21 5.97

166 07304500

U 42.6 7.11 0.29 0.00 0.00 40.2 6.59 1.02 0.18 0.00 38.3 9.91 2.01 0.46 0.00

R 41.2 10.6 2.02 0.91 0.45 44.7 16.0 4.11 1.50 0.40 30.5 15.4 6.62 2.41 1.38

167 07305000

R 166 52.9 12.6 2.62 0.08 150 50.9 21.3 8.36 1.21 115 54.3 22.9 11.4 3.53
Tables 75

Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Monthly flow-duration statistics

OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95

168 07305500 R 0.17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

169 07307028 R 352 99.5 35.0 20.0 13.9 333 128 56.0 38.5 28.4 318 125 72.8 46.8 31.8

170 07308500 U 842 221 53.9 22.4 12.1 842 295 97.6 49.5 21.5 601 271 103 61.2 39.7

171 07311000 U 101 16.3 6.67 2.35 0.04 69.0 17.8 8.81 4.35 0.29 56.9 21.4 10.2 7.08 4.62

R 73.1 29.1 17.6 13.7 11.0 88.6 36.7 21.3 17.0 14.4 90.2 38.7 24.9 21.0 18.3

172 07311200 R 3.49 0.08 0.00 0.00 0.00 8.07 1.14 0.00 0.00 0.00 7.70 1.54 0.04 0.00 0.00

173 07311500 U 24.0 3.22 0.00 0.00 0.00 26.8 3.65 0.32 0.00 0.00 17.3 4.01 0.40 0.12 0.00

174 07313000 U 11.4 0.57 0.02 0.01 0.01 19.0 5.03 0.04 0.02 0.01 18.1 7.58 1.36 0.04 0.02

175 07313500 U 27.3 3.66 0.00 0.00 0.00 60.3 9.49 0.09 0.00 0.00 44.8 15.6 0.25 0.00 0.00

R 6.90 0.23 0.00 0.00 0.00 27.8 0.65 0.00 0.00 0.00 28.7 0.74 0.00 0.00 0.00

176 07315500 R 2,050 598 219 140 106 1,630 558 243 142 114 1,030 458 239 161 123

177 07315700 U 25.3 3.00 0.15 0.00 0.00 36.5 4.85 0.20 0.00 0.00 53.1 7.13 0.51 0.07 0.00

178 07316000 R 2,570 703 257 167 123 2,330 740 280 193 148 1,580 613 290 193 156

179 07316500 U 10.2 0.48 0.00 0.00 0.00 16.8 4.93 0.00 0.00 0.00 23.2 9.41 0.00 0.00 0.00

180 07319500 U 2.20 0.77 0.19 0.00 0.00 3.30 1.26 0.51 0.00 0.00 3.50 1.36 0.58 0.01 0.00181 07323000 U 5.49 0.99 0.03 0.00 0.00 5.90 1.64 0.27 0.00 0.00 6.35 2.30 0.41 0.18 0.00182 07324200 U 33.5 8.18 0.50 0.02 0.00 51.2 14.6 0.93 0.21 0.00 58.9 21.4 2.48 0.25 0.03183 07324400 R 11.6 6.35 3.61 0.58 0.25 14.2 7.27 4.16 2.39 0.82 12.1 7.23 4.26 2.86 1.20

184 07325000 U 59.3 12.1 2.32 0.31 0.12 37.3 14.1 4.90 1.87 0.84 38.1 14.8 5.43 2.77 1.59

R 63.7 23.6 11.6 5.69 3.02 72.5 31.4 13.1 8.11 5.35 62.5 31.3 15.7 8.90 6.29

185 07325500 U 277 85.3 31.3 20.2 12.6 260 99.7 41.9 28.7 19.2 210 98.4 45.2 31.2 21.4

186 07325800 U 22.0 11.9 6.35 4.35 3.48 28.5 16.7 11.0 7.89 6.26 27.9 17.6 12.1 9.06 7.24

187 07326000 U 31.4 14.3 8.78 6.74 4.82 36.3 23.1 15.1 11.9 9.06 40.1 28.3 20.7 15.0 12.9

R 3.72 2.71 2.13 1.76 1.55 4.78 3.12 2.35 1.99 1.68 4.88 3.13 2.26 1.87 1.66
76 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Monthly flow-duration statistics OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95 188 07326500

R 387 125 58.3 43.8 34.3 421 165 76.4 54.9 44.6 336 175 81.1 61.3 50.4

189 07327000

U 13.2 2.36 0.04 0.02 0.01 12.0 4.89 0.81 0.04 0.02 16.9 6.83 2.27 0.87 0.05

190 073274406

U 1.30 0.26 0.13 0.07 0.04 1.56 0.70 0.21 0.15 0.05 1.40 0.73 0.24 0.18 0.08

191 07327442

U 4.95 0.82 0.49 0.31 0.22 5.64 2.99 0.77 0.54 0.46 5.53 3.27 1.19 0.56 0.47

192 07327447

U 18.7 7.38 3.37 2.60 1.70 21.4 12.3 6.26 4.84 4.03 22.5 14.3 8.20 5.87 4.86

193 07327490

U 28.2 8.83 3.31 1.20 0.04 35.4 16.6 7.15 4.42 3.42 34.3 18.3 9.57 7.20 5.71

194 07327550

U 45.7 16.9 6.33 4.82 4.18 60.5 37.0 13.4 8.56 6.96 64.9 37.5 16.6 10.3 9.20

195 07328000

U 455 142 54.2 38.5 33.7 396 174 94.8 47.3 29.9 352 197 114 83.7 55.4

196 07328070

U 9.06 2.65 0.90 0.53 0.37 12.8 4.18 2.05 1.38 1.09 10.1 4.80 2.38 1.89 1.48

197 07328100

R 590 209 83.4 59.5 45.8 664 290 117 76.8 60.8 514 271 124 92.5 75.1

198 07328180

U 1.43 0.58 0.08 0.00 0.00 2.57 1.00 0.34 0.04 0.00 2.80 1.07 0.24 0.08 0.05

199 07328500

U 680 161 61.8 31.0 11.0 464 210 90.8 42.7 31.4 430 211 120 70.7 54.1

R 855 302 105 66.1 48.1 1,030 395 147 96.3 69.4 730 368 155 113 91.1

200 07329000

U 32.9 11.5 3.23 0.62 0.00 45.4 19.7 7.60 4.61 0.33 46.1 20.3 10.8 6.53 3.66

201 07329500

U 25.8 9.91 0.90 0.00 0.00 35.7 11.9 2.62 0.96 0.50 30.2 12.7 4.12 1.97 1.18

202 07329700

R 171 26.7 3.85 1.53 1.07 176 50.7 7.47 3.34 2.51 190 47.2 13.6 5.13 2.21

203 07329852

U 23.1 12.8 6.71 4.81 2.60 38.2 15.1 8.01 5.92 3.97 47.1 17.3 8.63 5.61 4.36

204 07329900

U 28.5 11.6 5.39 3.22 1.95 39.6 18.1 8.16 5.93 4.89 56.7 25.4 8.48 6.77 5.35

205 07330500

U 47.2 2.22 0.03 0.02 0.01 34.6 5.06 0.05 0.02 0.01 47.6 9.26 1.81 0.03 0.02

206 07331000

U 982 300 121 77.5 15.9 845 352 170 80.9 51.2 785 379 191 133 86.5

R 1,590 493 161 91.9 69.8 1,980 658 223 150 93.0 1,700 684 235 185 126

207 07331600

U 8,360 1,900 578 397 273 3,940 1,410 713 552 414 4,460 1,480 649 466 318

R 4,770 2,170 217 90.9 70.9 4,730 2,140 348 98.1 64.5 5,070 2,470 644 148 84.1

208 07332400

U 97.7 44.2 32.8 30.2 28.8 131 55.6 36.8 31.9 29.5 133 64.1 34.8 30.3 28.1
Tables 77

Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station

ID

Type 

of 

record

Monthly flow-duration statistics

OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95

209 07332500 U 117 49.3 29.1 21.9 13.9 197 63.2 36.1 28.9 21.8 248 87.9 37.4 30.0 25.3

210 07332600 U 13.3 0.26 0.00 0.00 0.00 25.0 4.62 0.04 0.00 0.00 37.4 8.17 0.12 0.02 0.00

211 07333500 U 3.69 0.43 0.00 0.00 0.00 5.20 0.25 0.02 0.01 0.00 11.6 0.99 0.00 0.00 0.00

212 07333800 U 7.26 1.35 0.00 0.00 0.00 19.1 2.34 0.00 0.00 0.00 44.9 4.96 0.00 0.00 0.00

213 07334000 U 208 16.8 1.22 0.10 0.00 335 40.8 4.14 0.85 0.00 412 61.6 11.8 3.93 1.66

R 89.4 30.9 16.5 13.6 12.2 1,410 44.9 24.5 19.7 17.2 1,730 208 32.3 24.7 19.8

214 07335000 U 176 30.4 10.3 4.98 2.11 288 50.2 15.6 9.22 5.22 288 75.7 18.3 12.0 9.04

215 07335300 R 398 139 54.5 30.1 21.6 3,100 188 91.8 56.3 35.7 3,830 637 112 77.1 44.2

216 07335400 R 69.3 0.00 0.00 0.00 0.00 153 3.11 0.00 0.00 0.00 273 38.3 0.00 0.00 0.00

217 07335500 R 6,960 2,890 1,320 723 392 9,850 3,030 1,480 934 573 11,000 3,830 1,590 1,000 730

218 07335700 U 28.0 2.28 0.00 0.00 0.00 104 26.7 4.06 0.29 0.00 150 51.3 19.2 5.98 0.73

219 07335790 R 205 12.2 0.85 0.00 0.00 2,180 223 6.78 1.60 0.11 2,690 544 109 28.0 5.77

220 07336000 U 14.7 1.49 0.00 0.00 0.00 23.1 2.83 0.00 0.00 0.00 55.3 7.19 0.44 0.00 0.00

221 07336200 U 471 33.5 6.92 2.45 0.00 1,760 295 73.4 43.3 6.30 1,190 367 150 87.1 60.0

R 306 34.2 4.40 1.38 0.03 3,190 332 18.5 4.94 1.75 3,860 805 166 10.6 5.74

222 07336500 U 658 83.6 7.59 0.35 0.03 1,030 221 23.2 7.88 1.43 1,640 385 84.1 36.8 22.7

223 07336750 U 1.93 0.00 0.00 0.00 0.00 31.2 0.29 0.00 0.00 0.00 44.9 3.17 0.00 0.00 0.00

224 07336800 U 2.56 0.08 0.00 0.00 0.00 21.9 0.72 0.00 0.00 0.00 46.2 4.89 0.00 0.00 0.00

225 07336820 R 10,700 3,830 2,080 1,360 937 26,500 5,130 2,530 1,730 1,310 23,000 7,310 3,070 1,790 1,300

226 07337500 U 259 44.4 1.22 0.31 0.05 602 137 15.4 3.68 2.18 925 257 69.3 29.7 5.69

R 460 40.5 18.5 14.0 11.9 1,570 106 26.6 19.1 12.9 2,000 371 47.9 34.9 22.0

227 07337900 U 190 20.4 2.48 0.68 0.25 606 140 17.8 4.08 0.94 819 243 60.4 13.3 4.64

228 07338500 U 393 80.9 10.5 5.00 2.69 1,130 257 34.5 15.5 7.37 2,100 537 151 76.6 34.6

R 1,220 98.4 39.1 28.5 24.2 4,590 508 85.1 51.4 35.9 5,180 1,320 197 93.8 45.3

229 07338750 U 243 45.9 5.91 3.41 1.72 973 245 43.7 16.9 8.58 1,130 456 143 39.1 9.71

230 07339000 U 390 76.2 5.23 0.31 0.03 1,080 225 42.9 13.1 0.25 1,710 499 138 72.5 44.3

R 673 275 156 126 111 1,450 310 143 120 102 3,500 801 182 129 111
78 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 3. October, November, and December flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1. Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; OCTDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of rec- ord Monthly flow-duration statistics OCTD20 OCTD50 OCTD80 OCTD90 OCTD95 NOVD20 NOVD50 NOVD80 NOVD90 NOVD95 DECD20 DECD50 DECD80 DECD90 DECD95 231 07339500

U 80.8 11.5 0.94 0.31 0.04 162 37.7 6.47 0.93 0.54 353 94.1 20.6 10.3 4.00

232 07340300

U 62.8 21.6 13.8 12.1 10.2 230 67.3 25.3 19.1 15.8 330 114 50.9 32.1 21.1

233 07340500

U 162 34.2 12.1 8.08 5.76 489 111 33.7 22.5 17.0 848 233 61.9 40.1 29.0

234 07341000

U 44.8 5.83 0.21 0.09 0.07 150 27.1 5.83 1.04 0.10 268 73.3 13.4 6.56 3.40

235 07341200

U 51.2 6.58 1.05 0.69 0.51 228 25.8 3.95 2.22 1.22 463 106 15.2 7.39 2.74
Tables 79

Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS

station ID

Type of 

record

Monthly flow-duration statistics

JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95

1 07146500 U 719 420 231 142 58.8 906 503 293 170 50.2 1,170 614 382 306 249

R 1,400 818 471 375 293 1,800 923 523 408 331 3,030 1,270 568 440 384

2 07148140 R 3,240 1,250 482 341 277 2,620 1,350 504 366 299 6,640 1,860 414 192 157

3 07148350 U 74.1 39.5 17.8 5.04 1.82 81.1 47.0 25.1 16.5 10.7 133 50.2 26.1 17.8 13.5

4 07148400 U 103 52.4 26.4 13.2 4.52 127 61.3 30.2 17.2 7.59 192 72.1 36.1 28.3 20.1

5 07149000 U 147 97.4 61.3 43.7 30.9 166 103 67.8 56.0 47.3 220 114 74.5 60.0 52.7

6 07149500 U 230 120 65.5 34.3 24.9 253 125 75.9 58.0 43.7 380 173 114 92.0 78.5

7 07150500 R 289 141 20.9 2.37 1.24 343 155 42.7 3.72 1.70 618 208 65.7 16.1 4.11

8 07151000 R 570 228 76.0 28.9 14.9 690 278 90.3 35.3 18.7 1,300 350 128 58.7 21.6

9 07151500 U 163 99.2 57.0 38.4 25.9 204 110 65.2 51.4 40.9 347 139 74.3 55.0 42.1

10 07152000 U 286 146 69.5 42.8 22.7 362 164 87.9 62.8 40.9 591 201 96.5 60.6 43.6

11 07152500 U 2,890 1,470 671 475 293 3,110 1,600 704 510 388 4,760 1,860 786 566 455

R 5,850 2,200 922 529 357 6,950 2,870 1,170 814 567 14,700 4,900 1,030 595 468

12 07153000 U 48.5 12.6 3.85 2.08 1.12 76.8 15.3 4.58 2.42 1.17 237 27.5 6.13 2.59 0.63

13 07153100 R 0.35 0.03 0.01 0.01 0.00 1.50 0.03 0.01 0.01 0.00 4.51 0.05 0.02 0.01 0.00

14 07154500 U 2.89 1.57 0.63 0.34 0.04 3.07 1.74 0.68 0.20 0.10 2.61 1.57 0.32 0.10 0.03

UI 2.42 1.00 0.08 0.02 0.00 2.28 1.00 0.09 0.02 0.01 1.86 0.55 0.07 0.01 0.00

15 07155000 U 18.0 3.63 0.04 0.02 0.01 16.1 4.5 0.04 0.02 0.01 12.9 3.20 0.10 0.03 0.01

16 07155590 U 0.00 0.00 0.00 0.00 0.00 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

UI 0.01 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00

17 07156900 U 91.1 71.6 54.3 45.0 33.4 86.7 71.9 55.1 46.5 39.4 85.5 70.2 55.8 48.5 42.4

UI 46.2 40.9 33.9 31.1 29.1 49.0 42.7 34.9 32.4 30.3 52.7 44.5 38.0 34.5 32.7

18 07157000 U 104 65.7 42.2 30.3 23.0 103 70.3 48.3 38.8 32.7 95.6 68.8 50.1 41.2 33.7

19 07157500 U 24.8 16.8 9.48 6.55 5.06 25.4 17.6 12.0 9.59 8.15 27.9 19.2 13.1 10.5 8.48

UI 13.6 9.66 7.14 5.98 5.18 14.1 10.4 7.46 6.20 5.23 15.2 10.7 7.78 6.86 5.40

20 07157900 U 2.71 1.72 1.18 1.01 0.79 2.52 1.69 1.19 1.00 0.85 2.56 1.80 1.39 1.11 0.97

21 07157950 U 134 74.2 36.4 23.1 16.0 164 97.9 58.4 41.9 29.8 174 94.6 52.4 33.6 24.4

22 07157960 U 10.1 2.53 1.03 0.66 0.10 11.4 3.4 1.23 0.92 0.62 15.5 5.52 1.67 1.08 0.84
80 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95 23 07158000

U 219 108 45.5 26.7 10.3 266 131 68.4 49.4 35.3 308 136 63.5 44.0 33.1

24 07158400

U 16.3 8.00 5.07 4.03 3.53 21.3 9.6 6.37 4.76 3.08 20.4 9.75 5.47 4.00 2.54

25 07159000

U 7.43 2.09 0.41 0.20 0.10 8.65 2.61 0.55 0.30 0.22 11.1 3.16 0.53 0.25 0.09

26 07159100

U 558 283 144 98.0 68.8 684 299 182 129 97.6 1,420 411 183 142 97.2

27 07159750

U 115 55.6 26.2 20.5 17.8 142 62.0 35.7 24.6 19.7 190 77.4 39.0 29.8 23.3

28 07160000

U 1,070 578 353 280 236 1,370 526 332 275 242 2,580 874 328 250 202

29 07160350

U 18.6 12.8 7.25 5.64 4.75 23.6 14.3 8.37 6.51 5.67 28.6 16.6 8.36 6.27 5.49

30 07160500

U 45.0 14.6 7.17 4.39 3.39 50.8 17.9 7.99 5.11 3.81 94.3 19.0 8.08 5.49 3.95

31 07163000

U 2.45 0.59 0.12 0.00 0.00 3.72 1.14 0.21 0.09 0.00 7.43 1.66 0.27 0.09 0.00

32 07163500

U 360 189 80.6 34.3 16.0 426 227 99.2 61.7 44.7 682 222 103 66.2 49.9

33 07164000

U 681 360 177 111 24.1 952 436 215 155 128 1,360 563 247 152 106

34 07164500

U 3,490 1,680 848 581 316 3,740 2,010 858 620 495 5,680 2,240 1,030 750 613

R 8,050 3,120 957 402 223 9,370 3,420 1,010 481 287 20,800 5,350 1,210 707 438

35 07164600 UUrb 8.49 2.94 1.42 1.09 0.87 8.69 3.05 1.46 1.00 0.81 13.3 4.00 1.83 1.38 0.93

36 07165500

R 15.6 0.79 0.00 0.00 0.00 21.8 2.8 0.00 0.00 0.00 52.3 7.01 0.00 0.00 0.00

37 07165562 UUrb 7.16 2.47 0.61 0.31 0.08 9.39 2.76 1.11 0.53 0.37 18.7 4.87 1.87 0.80 0.50

38 07165565 UUrb 3.33 0.92 0.20 0.11 0.03 3.69 1.13 0.30 0.12 0.03 7.86 2.17 0.61 0.20 0.01

39 07165570

R 10,800 3,790 1,350 741 558 13,000 4,360 1,760 843 557 26,100 9,210 2,130 964 672

40 07170500

U 672 208 23.0 11.4 6.92 757 259 40.4 10.5 5.53 1,470 387 78.8 29.6 9.11

R 1,890 386 61.4 31.0 20.4 2,740 623 106 40.5 26.3 6,350 1,070 93.3 35.5 25.7

41 07170700

U 9.02 2.09 0.27 0.06 0.00 14.3 3.2 0.52 0.24 0.07 29.2 6.13 1.60 0.49 0.13

R 21.3 0.82 0.01 0.00 0.00 23.0 0.7 0.01 0.00 0.00 57.7 2.23 0.02 0.00 0.00

42 07171000

U 759 164 20.1 8.20 4.34 1,020 250 20.1 10.2 6.81 2,420 557 32.5 8.97 4.29

R 2,260 517 99.6 40.5 21.0 3,150 804 152 58.7 35.7 8,150 1,420 154 50.7 29.4

43 07171400

R 4,240 526 26.8 8.48 1.25 3,820 607 38.0 1.87 0.88 7,500 1,460 95.6 18.1 1.61

44 07172000

U 165 44.1 4.64 0.51 0.00 235 58.0 4.44 0.73 0.00 473 114 6.78 0.37 0.00

45 07173000

U 280 34.1 9.35 4.99 1.40 271 47.9 10.8 6.05 2.64 686 100 11.9 6.34 1.38
Tables 81

Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS

station ID

Type of 

record

Monthly flow-duration statistics

JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95

46 07174200 U 94.1 14.8 1.30 0.22 0.07 130 20.0 2.76 0.41 0.19 330 61.8 7.83 0.54 0.11

47 07174400 R 1,110 99.4 27.7 8.51 4.37 1,440 199 24.6 7.46 4.74 4,330 630 28.9 16.8 8.47

48 07174600 U 43.3 13.1 2.85 0.50 0.00 68.8 18.5 3.58 1.44 0.00 135 29.4 5.26 1.79 0.25

49 07174700 R 802 109 27.9 18.0 10.0 590 119 31.9 19.0 12.1 2,250 300 47.7 22.6 16.4

50 07175000 U 1.29 0.00 0.00 0.00 0.00 0.80 0.14 0.00 0.00 0.00 1.92 0.41 0.00 0.00 0.00

51 07175500 R 1,740 220 68.6 29.7 17.2 1,840 331 74.0 47.0 30.4 5,680 1,460 94.0 43.0 32.5

52 07176000 U 1,660 417 43.6 23.0 10.7 2,390 647 62.4 28.2 18.8 4,560 1,110 118 31.9 9.17

R 5,990 676 100 43.6 34.5 6,600 1,040 112 51.3 36.7 13,100 3,140 210 67.2 42.5

53 07176465 R 16.2 3.48 1.57 1.09 0.17 28.0 4.8 1.71 0.86 0.19 114 8.17 2.44 0.51 0.21

54 07176500 U 71.0 10.1 1.46 0.17 0.00 101 14.2 1.86 0.33 0.00 196 29.7 3.29 0.47 0.00

R 126 33.9 10.8 6.93 4.53 273 51.8 17.2 10.6 6.03 704 133 23.3 14.1 8.52

55 07176800 U 7.13 1.03 0.10 0.00 0.00 13.0 2.3 0.39 0.06 0.00 37.6 5.30 0.59 0.24 0.00

56 07177000 U 44.0 7.76 1.57 0.25 0.00 55.8 12.4 2.54 1.27 0.00 166 29.7 5.24 1.73 0.08

57 07177500 U 125 32.1 7.33 2.86 0.78 214 47.4 11.3 5.22 1.49 512 87.1 18.8 5.96 2.16

R 401 92.1 66.6 57.5 52.8 683 106 70.3 58.8 49.3 2,410 309 79.5 65.8 56.1

58 07177650 UUrb 4.36 0.92 0.20 0.08 0.02 5.06 1.19 0.25 0.04 0.02 7.77 2.93 0.55 0.15 0.02

59 07177800 UUrb 5.47 2.45 1.27 0.88 0.52 5.54 2.86 1.28 0.92 0.64 9.26 3.79 1.94 1.28 0.89

60 07178000 R 454 119 81.6 72.9 68.5 686 149 88.7 80.3 72.1 2,410 314 110 90.1 82.5

61 07178040 UUrb 50.8 20.8 8.17 5.12 3.93 43.3 16.7 7.82 5.17 2.62 99.4 29.7 11.1 6.81 4.52

62 07178200 R 662 213 138 119 106 957 247 140 121 106 2,810 440 175 133 11263 07178600 U 1,750 384 89.7 52.1 34.5 3,020 542 106 64.3 51.0 8,490 1,720 203 72.2 42.7

64 07184000 U 64.4 16.1 2.49 0.04 0.00 94.1 20.0 3.21 0.66 0.00 132 29.2 5.01 0.89 0.04

65 07185000 U 1,650 508 91.6 18.5 10.4 2,290 737 108 38.0 23.3 5,130 1,310 196 31.9 15.9

R 2,800 664 131 70.1 48.3 4,270 947 248 99.1 70.6 7,710 1,950 276 89.9 63.1

66 07185095 UUrb 41.2 14.9 7.40 3.87 1.47 59.1 17.6 9.45 5.62 0.75 75.6 20.8 7.74 4.21 1.33

67 07185500 U 2.28 0.73 0.10 0.00 0.00 3.18 1.08 0.13 0.00 0.00 4.76 2.04 0.45 0.11 0.00

68 07185700 U 255 97.0 51.4 39.1 30.7 339 104 58.9 42.5 31.2 371 214 80.4 65.5 46.5
82 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95 69 07185765

U 512 209 85.8 53.1 46.6 580 275 111 86.3 42.3 780 373 140 100 66.0

70 07186000

U 893 332 103 55.4 40.6 1,040 424 127 71.9 46.0 1,370 549 222 106 53.5

71 07186400

U 248 118 41.9 31.4 22.5 295 152 47.9 36.4 25.2 470 179 88.4 45.0 37.0

72 07187000

U 466 221 109 81.6 64.1 528 274 120 92.1 71.7 795 367 201 107 81.4

73 07187500

U 451 264 126 79.8 65.6 435 281 143 109 68.5 404 270 155 110 83.3

74 07188000

U 2,090 818 298 198 151 2,630 1,090 355 226 167 3,650 1,540 636 285 187

75 07188500

U 24.0 8.12 4.31 3.49 3.00 35.8 10.4 5.13 4.19 3.74 55.7 26.4 9.64 3.82 3.26

76 07189000

U 941 355 159 106 70.8 1,080 506 187 130 86.5 1,780 760 316 180 126

77 07189500

U 6,350 2,970 1,020 640 377 5,650 3,070 1,270 942 779 5,430 2,400 1,410 1,030 872

78 07189540

U 6.54 3.34 2.49 2.21 1.94 5.95 4.29 2.67 2.15 1.95 6.65 4.45 3.14 2.56 2.14

79 07189542

U 57.1 21.9 12.5 10.1 8.94 41.7 30.1 13.9 9.60 8.11 56.8 30.8 20.0 12.0 8.91

80 07190500

R 8,210 2,820 408 85.8 37.2 10,900 3,900 581 124 36.9 13,100 5,870 1,110 265 65.5

81 07191000

U 169 47.8 5.48 2.16 1.51 228 70.9 14.2 3.12 1.72 441 114 31.4 10.7 2.55

82 07191220

U 144 62.7 30.0 18.1 11.5 146 81.1 33.4 23.0 14.1 255 104 47.2 28.4 16.0

83 07191500

R 12,100 3,470 377 217 169 12,800 5,600 454 196 137 19,800 9,030 1,400 255 155

84 07192000

U 42.4 3.31 0.13 0.03 0.02 57.8 6.8 0.65 0.16 0.10 149 43.7 2.54 0.10 0.03

85 07192500

R 6,680 3,430 1,830 500 335 11,300 5,030 2,130 723 492 12,300 5,490 2,490 695 538

86 07193500

R 11,600 3,040 627 61.6 18.0 12,700 3,490 566 155 41.4 17,300 6,710 1,250 361 147

87 07194500

U 14,400 7,560 3,950 2,120 1,390 18,500 8,850 3,710 2,700 2,140 23,800 9,470 4,350 2,960 2,190

R 21,400 6,600 2,850 1,600 1,180 25,700 8,570 3,100 1,610 1,200 29,700 9,180 2,500 1,810 1,430

88 07194800

U 205 73.3 20.5 8.66 7.21 232 99.7 26.3 13.4 10.9 251 104 30.9 18.7 13.7

89 07195000

U 144 75.5 37.7 28.4 23.6 171 92.7 44.5 32.5 27.2 223 116 58.3 40.6 26.6

90 07195430

U 707 356 226 168 118 695 435 219 168 115 941 481 271 176 143

91 07195500

U 748 339 144 110 71.1 797 442 197 142 105 1,290 536 267 171 136

92 07195800

U 18.1 10.0 5.52 4.02 3.19 18.1 10.3 6.48 4.11 3.33 28.4 12.5 6.72 4.74 3.34

93 07195855

R 77.4 31.8 16.0 7.61 4.91 66.6 39.2 20.5 6.37 4.42 99.1 43.9 21.2 13.6 7.31
Tables 83

Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS

station ID

Type of 

record

Monthly flow-duration statistics

JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95

94 07195865 U 24.7 12.5 8.34 6.70 5.72 22.3 15.2 8.34 6.93 5.99 32.1 17.6 11.3 7.93 6.95

95 07196000 U 137 61.8 30.1 20.3 16.2 136 72.5 36.8 22.9 18.2 234 98.9 47.8 30.6 22.3

96 07196500 U 1,160 485 205 150 101 1,270 631 267 183 135 1,970 810 373 248 179

97 07196900 U 53.5 21.1 6.10 2.67 1.65 60.3 28.0 8.86 4.34 2.74 87.2 36.7 14.8 7.38 4.49

98 07196973 U 37.3 13.3 6.28 4.28 2.91 39.6 16.0 6.16 3.40 2.63 62.2 31.2 13.4 7.65 2.71

99 07197000 U 393 150 50.8 29.6 19.9 442 208 77.6 41.4 31.3 694 293 128 71.6 46.8

100 07197360 U 150 55.2 24.5 12.0 8.95 101 65.5 23.6 10.8 9.17 200 71.5 37.5 20.0 13.0

101 07198000 U 2,070 800 339 282 197 3,060 1,100 420 310 214 3,490 1,470 574 392 252

R 2,740 1,080 121 59.2 46.3 2,730 1,220 163 70.5 50.2 3,180 1,360 182 79.7 53.4

102 07228500 U 181 54.3 22.1 16.5 13.8 232 77.2 30.8 18.7 15.8 267 54.4 22.2 16.9 14.9

R 379 186 80.2 41.9 26.9 410 235 111 64.1 43.5 486 253 131 85.5 60.7

103 07229100 R 248 133 62.9 38.1 16.0 310 145 78.5 39.4 17.7 681 184 54.3 32.2 9.39

104 07229200 R 864 393 219 157 114 890 457 270 207 151 1,140 521 278 196 154

105 07229300 U 61.6 25.7 11.5 6.80 4.93 63.4 31.6 13.7 9.50 6.58 107 36.6 13.1 8.09 5.92

106 07230000 U 28.0 7.13 2.57 1.98 1.53 26.9 8.6 3.44 2.14 1.73 40.2 9.07 3.35 1.80 1.45

R 0.95 0.60 0.41 0.28 0.18 2.06 0.62 0.39 0.22 0.17 121 0.69 0.42 0.26 0.19

107 07230500 U 51.4 23.4 7.55 4.43 3.09 75.1 31.2 11.4 4.86 3.43 135 37.0 10.8 4.92 3.39

R 68.0 23.3 7.58 4.26 3.04 151 27.6 10.2 6.11 3.52 334 40.0 11.2 6.76 4.45

108 07231000 U 130 53.1 22.6 13.9 10.2 195 62.8 27.6 17.4 12.0 358 98.7 34.2 18.6 12.4

R 278 61.5 15.1 3.26 1.81 389 90.4 28.9 10.2 3.88 746 134 34.6 17.1 9.69

109 07231500 U 696 263 74.1 30.3 18.9 910 328 135 67.9 39.4 1,210 374 103 51.4 29.9

R 1,540 552 219 110 40.7 1,810 695 280 159 83.7 3,150 925 299 169 107

110 07232000 U 319 61.7 14.0 2.49 0.80 791 132 29.5 20.2 15.1 1,130 211 64.6 27.5 18.0

111 07232500 U 11.3 7.25 4.64 3.53 2.53 12.1 8.6 6.03 4.66 3.18 11.9 8.04 6.08 5.05 4.05

UI 1.54 0.00 0.00 0.00 0.00 3.38 0.00 0.00 0.00 0.00 4.10 1.02 0.00 0.00 0.00

112 07232900 UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

113 07233000 U 6.60 3.97 1.72 0.05 0.02 7.82 5.11 3.07 2.28 1.78 7.92 5.25 3.18 2.48 1.96
84 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95 114 07233500

U 1.75 0.55 0.14 0.00 0.00 1.34 0.55 0.22 0.10 0.00 1.26 0.62 0.25 0.00 0.00

115 07233650

R 1.72 1.17 0.74 0.55 0.46 1.83 1.27 0.75 0.61 0.52 2.10 1.39 1.04 0.73 0.47

116 07234000 RI 9.20 0.38 0.10 0.00 0.00 14.1 2.5 0.15 0.02 0.00 19.8 6.41 0.46 0.07 0.04

U 41.4 18.1 5.89 0.00 0.00 47.5 25.4 11.2 5.76 0.00 47.4 24.6 10.3 4.89 0.39

117 07234100

U 3.16 2.45 1.92 1.69 1.57 3.19 2.45 1.85 1.67 1.58 3.29 2.50 1.93 1.68 1.56

118 07234500

U 87.0 22.4 3.46 0.03 0.02 101 37.6 7.59 3.61 0.03 112 48.4 19.3 10.4 0.03

119 07235000

R 8.33 6.31 2.59 1.67 1.32 10.2 7.0 4.89 4.18 3.66 7.98 6.51 4.93 4.34 4.04

RI 4.28 2.49 1.30 0.94 0.67 5.70 3.00 1.59 1.18 0.72 7.97 3.44 1.85 1.39 1.15

120 07236000

U 53.9 41.3 22.1 13.8 9.69 62.2 42.6 27.2 19.0 14.4 71.6 47.4 29.6 23.2 19.7

121 07237000

R 53.8 28.2 1.40 0.84 0.36 60.0 37.2 4.68 0.68 0.13 63.3 29.2 2.52 0.82 0.34

RI 62.6 30.0 1.75 1.40 1.27 67.9 42.2 20.0 5.32 1.49 96.1 47.5 13.5 3.08 1.95

122 07237500

U 115 47.2 4.23 0.71 0.00 142 76.9 23.7 1.88 0.66 171 75.9 25.6 4.24 0.93

RI 136 67.1 19.7 13.8 11.3 161 82.5 39.4 21.6 15.7 203 106 54.2 40.9 29.5

123 07238000

U 135 58.3 1.98 0.00 0.00 180 96.4 22.6 0.00 0.00 242 102 32.5 3.40 0.00

RI 206 103 51.1 37.8 29.7 237 124 68.7 50.2 39.3 289 156 90.1 72.4 59.6

124 07239000

U 188 49.6 3.98 0.04 0.02 156 75.9 32.6 0.05 0.02 205 88.5 46.6 0.05 0.03

R 112 6.79 3.08 2.34 1.84 166 7.4 3.20 2.44 2.00 224 13.3 3.73 2.86 2.21

125 07239300

R 295 57.7 20.2 12.5 9.23 319 93.4 21.0 16.7 13.7 450 106 25.5 19.0 16.7

126 07239450

R 336 92.8 34.0 22.5 14.2 374 114 39.4 30.5 25.4 548 140 36.3 28.2 23.7

127 07239500

U 180 81.6 14.5 0.04 0.02 178 103 34.9 22.3 0.03 313 116 48.0 30.6 0.04

R 179 48.3 12.6 7.01 0.95 245 62.7 17.2 8.07 1.18 385 99.0 23.6 10.9 2.26

128 07241000

R 178 20.4 2.47 1.17 0.08 241 34.3 2.26 1.02 0.09 310 53.8 2.44 0.80 0.20

129 07241500

R 225 51.5 30.8 25.2 21.4 218 70.0 32.9 27.1 24.5 341 106 38.5 23.8 20.6

130 07241520

R 466 188 94.2 66.5 48.3 513 233 84.5 33.1 22.6 658 316 104 54.1 23.3

131 07241550

R 476 201 103 74.4 64.2 555 218 102 79.5 67.9 779 296 131 84.8 70.7

132 07242000

R 656 270 95.7 69.7 57.5 851 311 113 82.1 64.5 1,160 389 149 84.5 59.7

133 07242350 UUrb 40.7 26.9 19.2 15.9 13.4 45.7 27.0 20.0 16.6 14.7 54.2 31.8 22.1 18.5 15.4
Tables 85

Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS

station ID

Type of 

record

Monthly flow-duration statistics

JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95

134 07242380 R 197 68.1 40.8 27.9 24.0 208 64.7 40.1 28.9 23.2 376 107 50.0 38.0 26.3

135 07243000 U 11.9 3.78 0.45 0.03 0.00 14.4 4.6 0.98 0.32 0.00 24.8 6.30 1.14 0.56 0.00

136 07243500 U 481 150 46.0 28.5 17.9 781 191 63.7 41.5 26.9 1,680 295 89.8 46.5 22.0

137 07244000 U 322 123 39.1 23.5 14.0 1,280 195 75.7 36.9 25.9 1,460 241 89.8 30.4 16.7

138 07245000 U 2,840 1,190 356 173 132 4,840 1,470 576 379 247 8,110 2,240 665 300 208

R 9,040 2,870 429 127 69.3 9,730 3,520 512 129 68.4 15,200 3,530 330 110 66.3

139 07245500 U 175 74.0 24.0 5.00 2.04 269 99.0 29.3 15.1 7.81 487 162 51.5 23.9 13.8

140 07247000 U 307 99.6 26.2 10.0 2.85 402 126 42.6 20.3 11.3 494 163 51.4 28.1 17.5

141 07247015 U 647 165 44.3 24.3 7.51 545 160 48.6 26.4 13.2 578 183 60.3 34.2 22.2

142 07247250 U 280 99.1 33.3 22.7 4.95 254 103 42.8 24.2 11.2 261 112 43.5 27.9 21.7

143 07247500 U 129 32.2 6.45 2.03 0.75 188 54.9 15.4 7.77 4.24 271 76.5 21.0 10.7 6.78

144 07248500 U 1,060 438 153 48.3 33.2 3,600 837 154 114 97.4 2,880 775 210 110 82.3

R 1,910 390 87.0 12.9 1.09 2,190 552 164 62.1 10.2 3,290 939 238 89.8 32.4

145 07249400 U 184 68.4 20.5 2.80 0.63 241 88.4 32.7 15.0 4.22 295 115 44.1 23.7 12.3

146 07249413 R 6,660 2,070 277 73.5 15.1 6,030 2,180 277 109 32.3 6,440 2,010 458 165 101

147 07249500 U 38.4 14.0 1.72 0.66 0.37 47.7 20.3 5.99 3.92 2.87 83.9 34.4 13.5 5.85 3.23

148 07249985 U 716 242 64.3 21.2 5.03 866 350 127 63.3 29.7 1,410 572 228 122 55.1

149 07250000 U 631 225 56.7 17.3 5.52 750 322 125 65.5 38.3 1,400 560 236 127 57.4

150 07250550 U 28,900 10,900 5,300 2,930 1,920 32,400 14,200 5,810 4,440 3,790 44,500 18,200 7,620 4,750 3,200

R 53,500 19,600 7,230 3,560 1,200 55,900 25,100 8,500 4,350 2,340 108,500 39,400 12,200 6,540 3,290

151 07299200 U 2.11 1.25 0.53 0.28 0.19 2.21 1.05 0.50 0.22 0.12 2.13 0.91 0.32 0.09 0.03

152 07299300 U 0.26 0.15 0.10 0.07 0.05 0.27 0.15 0.07 0.06 0.04 0.66 0.17 0.08 0.06 0.05

153 07299540 U 41.9 11.8 4.25 2.75 1.83 50.7 12.8 4.08 2.68 1.79 48.8 10.1 3.14 1.77 1.01

154 07299570 U 32.1 10.4 4.32 2.85 2.06 41.2 12.5 3.95 2.75 2.11 32.7 9.34 3.33 1.94 1.06

155 07299670 U 17.1 7.95 3.37 2.19 1.62 16.8 7.9 3.70 2.24 1.73 18.1 7.95 3.70 2.40 1.83

156 07299890 U 4.10 2.87 1.73 1.40 0.84 4.31 2.96 2.09 1.64 1.27 5.50 3.80 2.21 1.63 0.66

157 07300500 U 69.4 31.8 12.9 5.21 0.00 74.9 34.9 16.5 9.56 3.07 81.1 31.4 8.83 1.60 0.00
86 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95 158 07301110

U 165 72.3 36.9 23.1 16.3 173 79.3 43.4 27.9 17.7 219 91.7 42.1 29.1 18.8

159 07301300

U 44.5 16.3 3.45 0.94 0.00 51.1 20.3 6.14 2.42 0.27 53.0 19.7 1.84 0.01 0.00

160 07301410

U 18.3 13.1 8.32 6.47 5.44 21.8 15.2 10.6 8.43 7.06 23.2 16.0 11.5 9.67 8.74

161 07301420

U 35.4 26.3 17.7 13.6 11.2 36.0 27.9 19.4 16.3 14.0 47.2 30.0 20.7 17.9 15.8

162 07301500

U 137 59.8 15.8 0.00 0.00 153 73.2 27.1 6.98 0.00 166 73.6 24.6 6.31 0.00

163 07303000

R 3.59 0.72 0.13 0.04 0.00 5.35 0.94 0.13 0.08 0.00 15.4 0.80 0.13 0.03 0.00

164 07303400

U 30.6 17.5 12.4 10.0 8.72 33.4 20.1 13.3 10.9 9.13 38.5 20.7 13.4 10.5 8.05

165 07303500

U 46.1 25.1 13.4 8.39 6.62 46.5 21.0 12.8 8.64 6.94 54.7 23.5 8.87 5.26 4.28

166 07304500

U 40.4 8.84 2.61 0.63 0.24 38.7 10.4 3.88 0.68 0.42 34.2 10.4 2.99 0.69 0.34

R 29.9 16.1 6.65 4.53 3.39 32.2 18.2 9.09 4.82 3.90 49.6 18.6 8.69 4.07 1.61

167 07305000

R 116 52.7 23.7 12.0 4.87 158 60.6 27.7 17.5 8.13 221 64.2 27.6 16.0 5.69

168 07305500

R 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.21 0.00 0.00 0.00 0.00

169 07307028

R 351 118 68.7 53.6 43.1 309 114 67.6 47.3 40.4 544 165 65.7 55.4 50.2

170 07308500

U 733 268 107 69.1 48.4 814 310 137 90.4 57.3 990 323 138 79.5 50.9

171 07311000

U 61.8 23.0 11.8 8.26 5.67 71.7 29.4 13.3 7.92 6.22 103 28.6 14.8 8.12 5.97

R 117 42.0 26.4 22.0 19.0 192 46.7 28.5 23.4 20.0 437 61.6 32.3 25.0 20.0

172 07311200

R 11.0 1.52 0.12 0.00 0.00 15.3 1.8 0.48 0.06 0.00 24.1 5.34 0.70 0.09 0.00

173 07311500

U 18.1 4.34 0.94 0.22 0.00 31.9 5.4 1.30 0.51 0.25 51.2 7.01 1.23 0.49 0.18

174 07313000

U 16.8 9.05 2.54 0.09 0.03 20.6 11.0 3.93 2.05 1.21 22.1 10.9 4.35 2.74 1.59

175 07313500

U 44.6 16.1 1.72 0.08 0.00 44.8 21.1 5.10 2.31 0.52 67.6 21.8 5.66 3.19 0.48

R 33.8 0.29 0.00 0.00 0.00 47.4 0.4 0.00 0.00 0.00 414 1.21 0.00 0.00 0.00

176 07315500

R 1,090 448 231 166 127 1,400 515 294 218 163 2,790 639 284 193 148

177 07315700

U 48.1 7.39 1.06 0.13 0.04 76.2 12.9 0.99 0.23 0.11 189 28.7 2.23 0.51 0.06

178 07316000

R 1,600 557 290 199 163 1,910 691 347 238 187 4,060 886 368 239 182

179 07316500

U 24.9 13.0 2.38 0.00 0.00 32.2 17.9 4.43 1.89 0.00 40.3 20.1 6.30 2.82 1.10

180 07319500

U 3.58 1.40 0.61 0.18 0.00 4.28 1.48 0.72 0.17 0.03 3.39 1.69 0.68 0.28 0.01
Tables 87

Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS

station ID

Type of 

record

Monthly flow-duration statistics

JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95

181 07323000 U 6.03 2.24 0.58 0.20 0.10 6.49 2.53 0.77 0.23 0.14 6.08 2.35 0.80 0.45 0.22

182 07324200 U 69.7 28.4 4.43 0.32 0.00 77.6 33.6 9.48 0.72 0.00 102 43.0 15.6 0.52 0.00

183 07324400 R 15.7 7.26 3.92 2.49 1.42 20.3 7.0 3.77 2.29 1.15 34.0 7.40 4.04 2.38 1.20

184 07325000 U 51.4 17.8 4.69 2.87 2.13 55.0 20.4 8.06 2.55 1.81 75.3 24.5 5.82 2.72 1.66

R 95.1 31.3 16.3 10.8 6.58 134 32.7 17.5 13.1 9.02 143 35.5 20.6 13.4 9.25

185 07325500 U 231 100 49.9 31.8 21.4 256 108 56.3 36.0 24.4 336 120 53.1 34.2 23.5

186 07325800 U 26.7 19.3 12.7 10.3 8.83 27.9 19.2 13.1 11.2 9.58 30.8 20.0 13.2 11.1 9.46

187 07326000 U 43.7 32.0 22.9 19.2 15.9 48.3 35.1 24.2 21.0 18.5 45.5 35.7 26.8 22.2 19.7

R 4.82 2.95 2.27 1.95 1.75 18.5 3.4 2.47 2.24 1.96 32.1 3.56 2.54 2.28 2.00

188 07326500 R 382 162 91.6 69.4 57.6 470 182 97.4 75.8 63.3 624 204 110 77.0 57.8

189 07327000 U 16.3 6.01 3.38 1.84 0.04 17.8 9.5 4.67 3.00 1.25 20.5 10.3 4.11 1.97 0.63

190 073274406 U 1.21 0.59 0.26 0.18 0.14 1.57 0.60 0.37 0.20 0.15 2.00 1.04 0.43 0.22 0.15

191 07327442 U 5.69 2.86 1.22 0.59 0.52 8.35 2.76 1.22 0.59 0.52 10.2 3.38 1.41 1.12 0.53

192 07327447 U 25.0 12.2 8.46 5.43 4.30 31.2 15.3 8.48 5.33 4.05 40.8 17.0 9.59 6.85 5.52

193 07327490 U 34.0 18.5 10.0 7.70 6.41 36.3 22.2 12.7 10.1 8.31 42.8 23.6 14.0 11.3 9.04

194 07327550 U 60.2 32.6 17.3 10.5 8.84 94.5 40.9 18.9 10.8 8.27 91.3 48.2 21.8 16.8 12.3

195 07328000 U 377 223 129 86.8 55.4 406 243 165 112 73.9 465 277 175 99.4 55.4

196 07328070 U 10.2 4.83 2.35 1.96 1.56 10.7 6.2 2.78 2.12 1.76 11.0 5.68 3.14 2.41 2.01

197 07328100 R 587 267 134 104 87.5 663 292 146 116 93.2 952 332 154 121 90.4

198 07328180 U 2.69 1.20 0.24 0.10 0.05 3.69 1.39 0.41 0.11 0.07 5.27 1.74 0.58 0.16 0.06

199 07328500 U 444 241 125 86.4 64.2 607 281 141 105 83.7 643 306 140 96.3 72.7

R 782 359 183 119 97.5 938 412 193 141 112 1,350 463 195 141 111

200 07329000 U 57.5 21.7 11.5 5.67 3.65 56.6 26.5 15.3 9.40 5.42 76.8 27.9 14.6 9.32 5.66

201 07329500 U 32.1 17.8 6.23 2.66 1.30 32.7 18.1 8.26 5.73 2.71 39.7 18.3 7.62 5.17 2.86

202 07329700 R 216 50.0 16.2 9.08 5.55 239 58.3 18.4 10.5 7.63 442 105 24.0 14.5 10.1

203 07329852 U 61.9 23.1 8.63 6.05 5.03 45.8 25.3 9.73 6.38 5.02 86.6 35.2 14.9 8.76 6.86

204 07329900 U 56.9 27.5 8.06 6.20 5.17 59.6 25.6 9.52 7.80 7.04 63.2 32.0 10.7 8.70 7.65
88 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95 205 07330500

U 54.8 19.4 2.88 0.29 0.04 115 26.1 12.3 2.45 1.51 137 42.3 11.0 2.04 1.36

206 07331000

U 858 427 221 147 100 1,140 467 253 189 149 1,350 604 269 171 135

R 1,670 632 278 190 128 1,970 694 314 228 188 3,130 920 356 245 177

207 07331600

U 3,250 1,490 815 574 280 3,730 1,470 774 603 521 4,470 1,940 812 432 302

R 5,470 2,680 645 156 96.2 5,220 2,450 694 217 117 5,800 2,160 470 119 81.9

208 07332400

U 128 79.3 35.9 30.6 28.2 159 82.1 42.7 30.2 25.9 228 99.3 54.2 37.9 25.7

209 07332500

U 247 108 43.9 31.3 25.1 332 136 57.1 39.1 31.4 413 152 67.3 43.7 31.8

210 07332600

U 29.9 8.68 1.17 0.09 0.00 47.5 16.8 2.54 0.68 0.01 53.2 18.2 5.55 1.83 0.40

211 07333500

U 12.1 1.75 0.00 0.00 0.00 15.0 3.5 0.42 0.13 0.00 32.2 8.26 1.33 0.63 0.19

212 07333800

U 42.8 5.61 0.87 0.28 0.00 42.1 8.4 1.40 0.19 0.00 112 29.0 8.05 2.81 0.58

213 07334000

U 407 89.2 15.0 6.43 2.10 1,030 184 42.4 23.2 13.8 1,400 253 58.4 28.8 15.0

R 1,740 259 51.5 33.0 27.4 1,300 260 72.6 41.2 28.3 2,220 530 79.8 48.6 35.5

214 07335000

U 277 93.8 24.6 13.5 9.85 518 138 44.6 22.1 15.3 879 202 68.5 36.5 19.6

215 07335300

R 3,860 703 213 113 77.8 3,330 881 315 194 108 6,060 1,310 325 217 166

216 07335400

R 147 30.8 0.00 0.00 0.00 289 108 0.00 0.00 0.00 504 128 15.1 0.00 0.00

217 07335500

R 10,600 4,430 1,900 1,210 804 13,300 5,070 2,160 1,430 1,080 17,800 5,140 2,150 1,440 1,000

218 07335700

U 116 50.1 20.2 11.3 4.93 136 61.7 29.0 18.5 9.57 172 71.3 33.1 21.1 13.3

219 07335790

R 2,390 561 107 61.5 29.2 2,220 633 188 98.1 49.7 2,640 913 226 117 74.6

220 07336000

U 47.2 9.60 1.22 0.24 0.00 82.3 19.4 4.17 1.35 0.57 84.9 27.7 9.36 4.20 2.12

221 07336200

U 1,420 461 118 87.7 47.3 2,500 860 326 228 113 4,070 1,280 458 236 149

R 3,400 796 194 104 19.9 3,150 936 296 155 84.1 4,050 1,300 359 200 121

222 07336500

U 2,390 680 200 87.9 49.6 2,700 880 349 200 125 2,900 1,080 447 265 175

223 07336750

U 47.3 9.82 0.40 0.00 0.00 89.1 15.6 3.77 0.00 0.00 129 11.9 2.88 1.72 0.32

224 07336800

U 48.3 6.63 0.09 0.00 0.00 113 19.3 0.48 0.00 0.00 156 25.7 2.60 1.42 0.63

225 07336820

R 21,400 8,270 3,200 1,900 1,370 22,300 9,520 3,990 2,590 1,890 33,500 12,500 3,930 2,480 1,760

226 07337500

U 1,220 414 126 43.1 21.8 1,790 624 218 127 94.0 1,790 649 318 211 120

R 1,310 375 66.5 27.8 21.1 1,660 637 197 79.4 20.7 2,770 616 110 51.8 32.8
Tables 89

Table 4. January, February, and March flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JANDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS

station ID

Type of 

record

Monthly flow-duration statistics

JAND20 JAND50 JAND80 JAND90 JAND95 FEBD20 FEBD50 FEBD80 FEBD90 FEBD95 MARD20 MARD50 MARD80 MARD90 MARD95

227 07337900 U 653 240 65.2 36.8 18.9 743 289 120 59.5 33.7 937 338 139 82.0 57.0

228 07338500 U 2,790 878 301 137 72.6 3,290 1,100 418 286 206 3,450 1,260 600 365 239

R 4,200 1,240 252 149 96.7 4,260 1,630 525 259 90.6 5,570 1,880 439 241 159

229 07338750 U 949 450 176 118 80.3 923 404 173 112 73.1 922 441 217 144 108

230 07339000 U 2,240 735 262 130 65.6 2,710 921 345 218 169 2,890 1,120 538 337 226

R 3,190 994 189 123 92.7 3,060 1,240 299 169 121 3,440 1,320 308 168 125

231 07339500 U 452 144 51.1 18.9 9.75 524 211 91.2 56.3 39.2 645 229 93.5 57.1 41.0

232 07340300 U 232 104 49.7 35.9 26.9 273 128 67.0 53.1 42.4 362 144 73.2 54.4 43.8

233 07340500 U 822 325 138 69.5 38.7 1,210 468 190 126 96.9 1,460 518 216 139 96.8

234 07341000 U 288 111 39.9 17.1 7.39 420 154 57.6 39.4 29.9 490 172 64.6 38.1 24.3

235 07341200 U 479 161 47.0 14.4 4.73 509 216 87.5 57.0 39.6 702 215 94.6 66.0 44.8
90 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95

1 07146500

U 1,620 707 358 272 211 3,610 1,190 509 365 282 5,500 1,790 574 314 232

R 3,330 1,380 656 472 415 4,130 1,720 748 548 400 5,490 1,900 930 637 448

2 07148140

R 8,730 2,760 637 510 154 6,120 2,770 959 386 175 8,750 4,290 1,580 856 660

3 07148350

U 146 55.1 22.9 14.9 10.5 179 67.0 15.6 5.33 1.57 196 65.0 13.0 3.23 0.45

4 07148400

U 269 89.2 34.7 23.8 15.6 324 114 35.2 17.5 8.59 307 107 29.4 10.2 3.46

5 07149000

U 272 117 71.4 58.9 52.6 293 129 61.6 42.1 30.6 289 114 46.0 26.7 16.0

6 07149500

U 831 175 103 80.0 65.0 925 242 87.9 59.4 39.7 581 137 37.9 11.0 4.83

7 07150500

R 750 246 62.0 22.0 6.10 1,100 354 88.9 16.6 7.51 1,240 346 69.7 17.5 7.50

8 07151000

R 1,790 461 119 58.4 36.6 2,060 632 177 90.5 45.8 2,500 642 185 74.1 29.1

9 07151500

U 355 159 83.0 56.4 37.1 417 186 80.4 50.8 31.8 505 158 62.3 37.9 19.0

10 07152000

U 685 237 99.3 59.7 42.6 874 303 106 62.5 33.4 1,080 290 100 52.3 30.8

11 07152500

U 7,360 2,640 1,050 604 454 11,200 3,760 1,330 913 577 13,300 4,370 1,680 950 601

R 15,400 5,390 1,510 804 495 13,300 6,370 2,730 1,690 1,120 18,600 7,810 3,200 2,100 1,450

12 07153000

U 229 45.1 8.43 3.43 1.65 586 65.3 14.3 6.16 2.57 362 44.4 9.15 3.24 1.44

13 07153100

R 3.05 0.05 0.02 0.01 0.00 11.4 0.22 0.02 0.01 0.01 1.80 0.04 0.02 0.01 0.00

14 07154500

U 2.07 0.75 0.03 0.02 0.01 4.39 1.07 0.04 0.02 0.01 13.2 1.16 0.03 0.02 0.01

UI 1.56 0.27 0.05 0.02 0.00 2.88 0.22 0.01 0.00 0.00 2.58 0.08 0.00 0.00 0.00

15 07155000

U 5.68 0.11 0.02 0.01 0.01 24.5 0.05 0.02 0.01 0.00 58.1 1.36 0.03 0.01 0.01

16 07155590

U 2.10 0.00 0.00 0.00 0.00 7.13 0.91 0.00 0.00 0.00 7.62 0.00 0.00 0.00 0.00

UI 0.10 0.00 0.00 0.00 0.00 0.09 0.00 0.00 0.00 0.00 0.04 0.00 0.00 0.00 0.00

17 07156900

U 97.4 75.3 61.7 55.2 50.3 95.7 68.6 53.5 46.6 41.6 85.0 57.6 43.9 40.2 35.3

UI 50.8 42.4 35.4 32.2 30.7 45.9 37.0 29.0 25.2 22.9 41.3 31.2 23.6 20.0 17.9

18 07157000

U 93.8 66.5 48.2 40.4 36.0 106 61.6 40.4 32.9 27.3 123 49.0 28.8 21.2 15.8

19 07157500

U 26.9 16.9 11.3 7.65 6.21 53.6 13.7 7.01 4.40 2.31 82.5 13.4 1.67 0.04 0.02

UI 16.8 11.7 7.86 6.76 5.60 16.7 10.3 6.31 5.23 4.44 18.2 8.60 4.67 3.15 2.32

20 07157900

U 2.48 1.73 1.18 0.86 0.62 2.75 1.78 1.18 0.98 0.78 2.66 1.60 0.82 0.62 0.53

21 07157950

U 176 59.2 22.3 14.9 9.89 236 68.3 13.0 4.05 0.97 248 64.5 8.28 1.26 0.07
Tables 91

Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type of 

record

Monthly flow-duration statistics

APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95

22 07157960 U 21.6 6.11 1.12 0.36 0.16 29.6 7.95 1.06 0.01 0.00 20.7 5.58 0.65 0.00 0.0023 07158000 U 382 123 35.4 18.8 9.42 579 168 27.2 9.02 3.26 614 155 26.9 5.70 0.7724 07158400 U 29.0 10.9 5.55 4.10 3.45 46.6 13.0 5.90 3.62 2.69 36.4 13.5 6.10 3.30 1.9825 07159000 U 14.6 4.24 0.51 0.23 0.08 45.3 5.20 0.53 0.20 0.09 65.0 5.03 0.29 0.00 0.0026 07159100 U 1,250 462 174 127 89.6 2,140 649 216 133 102 2,000 685 228 142 93.027 07159750 U 222 87.0 41.9 28.0 21.2 445 117 51.5 35.4 25.3 343 108 46.1 33.1 25.4

28 07160000 U 2,250 949 407 277 215 2,980 948 399 262 223 3,330 1,110 387 282 223

29 07160350 U 37.7 14.7 8.47 7.24 6.66 41.4 17.4 8.30 6.52 5.69 47.2 14.6 10.0 7.60 5.1930 07160500 U 112 26.9 9.01 5.65 4.29 192 36.3 11.1 5.96 3.99 187 34.9 11.2 5.36 3.4331 07163000 U 7.55 2.50 0.40 0.13 0.00 9.81 2.41 0.39 0.04 0.00 5.41 1.20 0.00 0.00 0.0032 07163500 U 2,520 479 154 62.7 44.5 3,690 1,070 206 127 85.2 4,120 1,530 523 342 28533 07164000 U 2,790 742 299 182 144 4,050 1,210 381 241 173 4,690 1,380 469 301 17534 07164500 U 10,300 3,530 1,360 791 582 17,500 5,680 1,840 1,290 1,060 19,800 6,460 2,500 1,300 811

R 21,000 7,330 1,490 785 521 23,600 8,850 2,710 1,310 735 24,100 10,500 3,860 2,260 1,250

35 07164600 UUrb 15.0 3.87 1.94 1.52 1.21 24.2 4.56 2.32 1.49 1.14 24.1 3.87 1.65 1.10 0.88

36 07165500 R 91.0 15.5 0.32 0.00 0.00 110 21.9 4.01 0.31 0.00 68.4 10.8 0.28 0.00 0.00

37 07165562 UUrb 15.1 3.74 1.38 0.74 0.45 25.5 4.62 1.43 0.74 0.33 20.3 3.28 0.70 0.32 0.05

38 07165565 UUrb 5.91 1.59 0.51 0.22 0.07 11.6 1.58 0.44 0.15 0.00 9.19 1.04 0.14 0.03 0.0039 07165570 R 26,000 10,500 2,650 1,380 773 27,800 12,100 4,650 2,510 1,460 28,000 11,900 5,300 3,320 2,330

40 07170500 U 2,890 726 149 49.8 26.8 3,240 823 286 158 92.7 3,930 634 128 49.5 19.7

R 5,490 1,220 165 50.7 29.5 6,050 1,650 297 148 76.7 7,840 2,010 206 89.9 49.5

41 07170700 U 23.1 6.81 1.32 0.69 0.32 22.1 4.94 1.11 0.39 0.25 20.7 2.73 0.42 0.13 0.05

R 37.0 7.39 0.06 0.00 0.00 77.8 11.8 0.48 0.03 0.00 55.6 11.2 0.13 0.02 0.00

42 07171000 U 4,850 786 146 35.8 10.7 4,430 1,010 333 136 50.9 4,930 655 138 57.0 25.5

R 6,910 1,640 240 83.2 41.6 7,820 2,160 471 234 141 9,460 2,500 285 131 67.5

43 07171400 R 10,400 3,110 82.6 30.0 18.2 6,530 1,670 130 35.4 23.5 9,770 3,150 168 31.6 20.1

44 07172000 U 521 177 27.2 3.76 0.26 582 166 48.6 23.2 11.9 446 91.6 24.2 10.9 4.88
92 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95 45 07173000

U 1,030 169 13.0 7.34 2.25 1,060 174 19.8 9.59 4.52 1,090 99.0 14.5 9.36 6.25

46 07174200

U 430 72.5 11.1 3.91 0.36 420 73.6 17.2 7.42 2.75 319 40.2 7.93 2.91 1.12

47 07174400

R 3,230 654 78.3 25.1 15.3 4,420 1,410 91.7 36.2 26.5 5,000 1,500 48.3 31.1 24.4

48 07174600

U 120 34.2 8.00 1.98 0.61 126 29.9 7.29 3.49 2.19 65.8 16.0 3.06 1.13 0.40

49 07174700

R 2,940 413 45.5 26.9 17.5 3,490 378 60.0 27.5 16.3 2,440 231 47.4 26.8 17.4

50 07175000

U 2.35 0.72 0.00 0.00 0.00 1.85 0.27 0.00 0.00 0.00 1.06 0.00 0.00 0.00 0.00

51 07175500

R 4,810 1,270 275 89.8 50.4 5,500 2,050 267 91.9 66.1 5,710 1,910 115 57.6 43.3

52 07176000

U 9,060 1,740 338 77.7 35.7 11,600 2,400 613 324 125 9,580 1,490 371 130 75.0

R 13,300 4,750 308 105 67.7 13,800 5,090 660 220 105 14,800 6,230 457 162 86.3

53 07176465

R 88.1 11.6 3.63 2.12 0.40 178 15.4 4.21 2.37 1.94 103 11.9 3.82 1.64 0.97

54 07176500

U 221 54.0 5.58 1.42 0.40 279 55.6 11.4 4.77 2.44 162 27.7 2.68 0.60 0.12

R 547 141 46.1 17.9 8.30 783 204 47.8 24.8 15.4 606 95.9 30.5 13.0 8.69

55 07176800

U 19.2 3.87 0.45 0.12 0.00 21.7 3.84 1.04 0.50 0.23 8.47 1.30 0.29 0.00 0.00

56 07177000

U 172 40.0 7.48 2.33 1.11 268 44.4 12.2 6.17 3.18 144 23.9 4.14 1.23 0.52

57 07177500

U 637 145 21.8 10.4 6.55 1,100 175 48.8 22.8 12.2 471 92.1 22.8 9.14 5.89

R 1,620 272 152 128 117 2,570 336 161 128 109 2,080 270 166 146 120

58 07177650 UUrb 5.98 1.67 0.42 0.18 0.09 5.13 1.14 0.28 0.11 0.00 3.27 0.57 0.10 0.02 0.00

59 07177800 UUrb 9.10 3.14 1.51 1.03 0.77 12.2 3.12 1.40 1.04 0.85 10.8 2.67 1.02 0.55 0.27

60 07178000

R 2,090 312 182 156 138 2,820 406 178 155 132 2,220 325 188 164 152

61 07178040 UUrb 106 23.7 8.85 5.99 4.53 96.4 18.5 5.56 3.70 2.96 77.3 13.3 3.96 2.85 2.00

62 07178200

R 1,970 457 253 211 184 3,250 720 278 214 187 2,820 573 265 226 195

63 07178600

U 10,000 2,400 441 168 59.0 16,700 3,050 805 314 172 9,430 1,470 374 146 90.3

64 07184000

U 123 25.8 6.51 1.71 0.21 176 28.0 6.75 3.28 1.70 196 24.9 3.65 1.49 0.51

65 07185000

U 7,100 1,820 453 206 63.5 9,180 2,210 609 327 170 10,300 2,110 547 274 176

R 8,630 2,490 376 126 75.5 10,500 2,830 802 458 284 12,700 4,650 971 427 262

66 07185095 UUrb 59.4 21.4 8.98 6.33 0.96 62.7 14.2 5.30 4.11 3.56 36.7 11.0 4.12 2.75 2.02

67 07185500

U 4.00 1.73 0.59 0.20 0.00 2.48 0.91 0.28 0.13 0.06 2.00 0.45 0.14 0.10 0.00
Tables 93

Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type of 

record

Monthly flow-duration statistics

APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95

68 07185700 U 503 229 126 71.6 55.3 457 248 121 95.0 79.5 463 203 111 72.7 55.2

69 07185765 U 642 394 195 106 70.3 637 325 217 158 128 583 260 140 89.1 59.570 07186000 U 1,450 596 259 136 74.1 1,490 530 263 180 129 1,580 498 204 134 92.271 07186400 U 411 216 93.2 64.1 43.2 311 150 93.1 63.0 47.7 259 128 68.2 53.0 37.0

72 07187000 U 797 404 222 154 91.9 852 398 242 178 134 755 333 188 147 10873 07187500 U 780 299 169 128 98.4 727 366 156 120 102 965 388 165 102 81.7

74 07188000 U 3,690 1,670 721 432 237 3,890 1,480 836 586 412 3,540 1,310 597 416 30375 07188500 U 52.0 30.1 12.6 4.05 3.51 59.3 27.5 10.7 6.25 4.38 47.6 18.7 10.6 6.66 4.4376 07189000 U 1,890 840 397 278 174 1,740 738 383 280 218 1,090 458 242 162 12477 07189500 U 12,300 4,490 1,760 1,060 811 15,100 4,330 1,910 1,310 982 28,700 4,890 1,720 997 60978 07189540 U 5.21 3.59 2.68 2.21 1.95 7.66 4.03 2.50 2.19 1.99 5.58 3.29 2.29 2.01 1.8379 07189542 U 43.0 27.1 17.2 12.6 8.67 79.5 31.1 19.3 16.8 15.5 34.1 19.0 14.0 10.9 8.8080 07190500 R 14,400 7,100 924 197 56.0 15,900 7,030 1,570 284 51.1 17,300 7,710 2,330 698 90.3

81 07191000 U 336 97.4 31.1 13.5 6.40 426 80.2 23.5 13.8 8.73 250 44.0 9.83 4.18 2.5682 07191220 U 242 116 54.3 40.1 23.4 193 95.4 52.4 36.7 25.5 148 65.9 38.0 24.0 15.983 07191500 R 20,200 10,400 1,420 241 152 20,600 9,620 1,470 327 186 21,500 10,300 2,370 570 232

84 07192000 U 110 31.8 4.92 1.25 0.05 215 30.8 4.86 2.92 1.16 87.1 7.06 1.45 0.40 0.11

85 07192500 R 38,400 7,420 3,960 870 448 26,800 9,290 3,380 2,350 580 26,700 11,400 3,670 870 313

86 07193500 R 20,200 10,200 1,050 330 105 16,500 7,240 1,140 317 86.4 17,600 8,500 2,120 715 147

87 07194500 U 55,100 14,200 6,010 3,740 2,310 57,500 21,800 8,220 5,380 4,200 67,000 23,200 7,830 5,080 3,110

R 51,100 27,600 4,800 2,060 1,270 62,900 20,300 8,620 5,480 3,520 63,100 31,900 8,180 4,620 3,580

88 07194800 U 257 94.4 34.2 22.9 15.8 240 86.7 32.1 23.1 18.6 133 40.2 19.7 14.0 10.789 07195000 U 207 124 62.5 45.0 27.7 215 116 71.4 45.2 36.3 176 96.8 53.4 37.1 29.0

90 07195430 U 810 417 258 204 158 780 407 269 224 193 564 300 202 156 110

91 07195500 U 1,260 600 271 202 153 1,140 520 285 202 156 746 348 197 138 110

92 07195800 U 26.7 13.8 6.97 4.98 3.91 23.7 11.5 6.65 5.29 3.89 19.2 8.30 4.77 3.49 2.76
94 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95 93 07195855

R 85.6 43.0 21.3 15.1 8.99 83.8 38.6 22.9 17.9 13.4 71.4 26.9 14.8 9.27 7.09

94 07195865

U 26.0 14.9 9.80 8.15 6.99 38.5 15.4 10.6 8.88 8.15 35.9 14.0 8.54 6.97 5.95

95 07196000

U 225 106 54.7 37.8 24.4 200 92.9 52.5 41.0 33.6 154 64.2 36.1 27.3 22.6

96 07196500

U 1,980 929 419 302 214 1,910 853 417 302 234 1,280 578 281 191 144

97 07196900

U 80.8 35.4 13.9 8.68 5.43 68.3 24.5 10.2 6.21 4.39 34.4 11.0 3.89 2.02 0.79

98 07196973

U 52.0 27.6 13.4 9.76 7.61 55.3 22.3 10.8 8.05 6.75 34.7 13.3 6.27 3.50 2.40

99 07197000

U 693 319 145 94.1 57.8 685 274 144 106 86.5 392 158 73.0 52.1 38.6

100 07197360

U 151 56.8 28.6 17.6 15.0 138 58.1 31.7 27.0 19.3 76.2 41.1 23.7 20.1 15.6

101 07198000

U 3,790 1,680 904 673 457 4,920 2,200 885 574 481 3,100 1,430 604 390 304

R 4,090 2,010 277 89.2 63.8 3,460 1,540 179 87.0 62.4 2,660 1,200 179 107 80.3

102 07228500

U 178 33.0 17.0 14.4 13.1 1,220 65.3 18.4 13.8 10.4 1,050 102 21.1 8.34 3.09

R 458 230 105 60.8 38.3 648 225 77.8 45.6 21.0 616 230 45.2 24.9 16.0

103 07229100

R 550 173 25.4 14.2 10.6 824 168 23.7 9.82 6.21 1,010 169 27.0 9.30 5.20

104 07229200

R 1,110 535 238 148 70.7 1,550 544 237 132 84.1 1,550 643 258 139 77.6

105 07229300

U 116 39.1 13.2 8.39 5.12 141 45.8 16.3 8.40 4.26 106 40.4 8.06 2.59 1.26

106 07230000

U 48.1 12.9 3.55 2.29 1.72 106 22.2 6.36 3.45 2.26 64.2 9.72 2.47 1.18 0.43

R 120 0.73 0.43 0.30 0.19 195 0.69 0.42 0.22 0.19 245 0.77 0.44 0.25 0.19

107 07230500

U 147 45.6 14.9 7.43 5.03 352 78.4 22.6 13.7 7.61 198 48.2 8.77 4.08 1.63

R 359 43.8 12.8 5.79 3.91 551 52.1 12.4 7.01 4.33 502 44.6 9.41 4.94 1.50

108 07231000

U 476 124 45.0 29.9 16.5 1,710 326 89.2 42.8 25.5 702 137 40.6 20.6 10.2

R 762 160 40.7 19.1 7.64 1,100 230 51.1 26.8 16.7 928 178 30.3 14.2 7.53

109 07231500

U 2,240 459 123 67.6 42.5 6,590 1,150 218 95.3 54.2 4,600 992 193 90.2 31.5

R 3,280 1,080 312 135 85.5 4,670 1,410 345 200 122 4,350 1,400 297 138 67.3

110 07232000

U 1,170 188 48.3 22.5 15.9 1,650 188 58.3 32.2 17.0 246 37.3 7.75 2.97 1.72

111 07232500

U 11.2 6.82 4.54 3.62 2.90 15.1 5.48 2.40 1.22 0.69 18.7 3.62 0.93 0.41 0.11

UI 3.30 0.48 0.00 0.00 0.00 2.99 0.00 0.00 0.00 0.00 1.86 0.03 0.01 0.00 0.00

112 07232900 UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
Tables 95

Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type of 

record

Monthly flow-duration statistics

APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95

113 07233000 U 7.84 4.90 2.49 1.68 1.21 12.8 3.87 0.90 0.04 0.02 13.3 2.39 0.03 0.01 0.01114 07233500 U 1.47 0.49 0.00 0.00 0.00 4.76 0.55 0.00 0.00 0.00 15.4 2.15 0.00 0.00 0.00115 07233650 R 1.93 1.30 0.98 0.79 0.40 1.82 1.15 0.61 0.38 0.27 1.31 0.55 0.05 0.00 0.00116 07234000 RI 23.5 7.79 2.35 0.11 0.05 31.7 11.4 0.56 0.06 0.01 31.3 5.86 0.06 0.00 0.00

U 52.2 20.4 4.38 0.45 0.00 127 19.5 0.49 0.00 0.00 248 39.7 0.37 0.00 0.00

117 07234100 U 3.05 2.36 1.82 1.51 1.27 3.38 2.38 1.66 1.34 1.17 3.31 2.18 1.39 1.11 0.85

118 07234500 U 164 51.0 16.7 9.13 0.03 347 67.8 11.7 3.33 0.83 402 96.4 8.90 2.45 0.14119 07235000 R 7.93 5.53 3.81 2.47 2.00 8.62 3.56 1.07 0.39 0.28 23.7 7.30 2.80 1.07 0.62

RI 11.2 3.46 1.94 1.54 1.25 15.0 3.42 1.31 0.78 0.56 14.2 4.01 0.99 0.48 0.33

120 07236000 U 78.1 43.7 25.2 18.5 14.5 187 52.3 22.7 15.8 11.8 170 33.2 5.09 2.06 0.52121 07237000 R 63.0 25.8 2.61 1.24 0.67 99.4 13.2 1.90 1.23 0.99 141 6.06 1.32 0.75 0.54

RI 88.5 43.2 20.2 2.97 1.89 119 39.4 17.5 2.40 1.54 122 32.1 3.67 2.01 1.27

122 07237500 U 191 76.5 21.9 4.27 1.59 437 79.7 12.0 3.39 1.23 727 125 15.3 3.53 0.00

RI 274 112 57.2 46.5 32.9 323 116 47.8 32.3 22.6 348 116 40.5 16.6 11.2

123 07238000 U 251 103 35.8 4.84 1.13 582 113 19.2 6.77 1.34 922 172 20.8 4.03 0.00

RI 373 170 86.8 66.4 56.3 517 181 81.6 54.8 39.9 492 184 64.4 35.5 16.3

124 07239000 U 520 148 41.7 0.05 0.03 861 211 46.1 10.5 2.23 738 254 43.9 14.7 1.18

R 285 21.9 4.64 3.17 2.38 324 23.1 6.12 4.15 3.10 744 35.1 6.53 4.64 3.69

125 07239300 R 586 145 32.1 24.1 20.3 600 129 26.5 18.0 11.4 762 202 40.4 20.3 12.0126 07239450 R 736 152 48.9 33.7 28.4 830 215 48.7 31.4 24.5 941 326 82.4 40.1 24.4127 07239500 U 499 213 65.3 28.9 1.70 930 302 122 26.6 5.62 726 278 106 44.4 23.5

R 494 118 27.9 12.2 5.32 699 132 34.7 13.4 5.09 879 212 32.5 9.67 2.72

128 07241000 R 272 38.3 2.55 1.18 0.43 468 50.7 2.36 1.10 0.22 698 109 2.30 0.83 0.10

129 07241500 R 621 131 48.8 36.6 26.2 1,190 288 56.7 41.7 30.4 1,560 236 52.3 40.8 31.3

130 07241520 R 862 268 89.2 43.0 21.0 1,080 331 80.1 41.1 31.4 1,300 480 107 49.9 32.8

131 07241550 R 871 314 124 79.8 68.1 1,180 379 145 98.2 76.6 1,200 503 175 113 84.6

132 07242000 R 1,430 530 173 123 91.3 2,280 745 250 152 114 2,230 777 221 127 88.2
96 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95 133 07242350 UUrb 54.7 31.8 23.6 20.9 18.3 126 46.8 26.0 19.8 15.1 95.1 46.5 25.4 17.9 12.4 134 07242380

R 493 114 47.0 36.4 30.4 722 144 48.4 34.3 25.8 705 159 43.9 29.2 23.6

135 07243000

U 24.1 7.48 1.57 0.79 0.09 30.8 8.96 2.39 0.83 0.22 24.8 5.92 1.31 0.28 0.00

136 07243500

U 2,080 445 120 65.5 41.0 3,340 761 200 107 64.2 2,800 491 117 71.6 44.2

137 07244000

U 3,610 517 137 85.5 47.4 5,390 1,990 302 117 56.2 4,300 752 174 73.7 30.5

138 07245000

U 11,900 3,310 1,090 520 263 23,400 7,400 1,640 829 529 15,700 4,180 1,060 549 311

R 13,800 4,880 671 142 70.0 18,600 6,260 1,060 258 98.5 16,600 5,680 1,560 567 181

139 07245500

U 485 172 72.9 27.4 18.3 480 166 68.3 42.3 30.4 211 56.5 19.9 10.1 6.32

140 07247000

U 410 119 39.6 24.5 15.9 427 94.0 21.6 11.9 8.03 173 25.4 5.50 2.26 1.15

141 07247015

U 409 115 42.3 28.4 22.7 404 79.0 27.0 18.0 12.5 237 46.9 14.1 8.36 6.23

142 07247250

U 208 91.2 44.5 33.2 21.0 184 56.1 26.0 17.2 11.6 139 30.8 8.37 3.70 1.50

143 07247500

U 286 71.6 22.1 11.3 6.91 287 49.0 14.0 7.41 4.83 98.5 16.9 3.97 1.54 0.50

144 07248500

U 3,900 1,020 385 250 182 3,250 834 217 157 123 812 244 107 73.1 53.7

R 3,350 682 150 73.8 31.5 4,910 980 89.0 34.5 21.4 3,230 85.5 11.8 7.90 5.00

145 07249400

U 243 83.2 34.9 20.5 11.1 223 56.4 19.0 12.5 8.75 84.4 23.3 7.11 3.45 1.97

146 07249413

R 6,140 1,930 375 167 102 6,290 1,960 298 121 80.6 4,260 894 135 75.3 57.0

147 07249500

U 96.8 44.2 17.8 8.20 4.83 88.8 28.0 8.78 5.24 3.84 18.1 4.83 1.53 1.00 0.63

148 07249985

U 1,370 578 228 141 98.0 1,090 375 123 69.3 45.9 395 109 34.0 17.6 8.95

149 07250000

U 1,350 580 239 149 104 1,100 396 135 74.6 46.9 395 109 30.1 14.7 6.79

150 07250550

U 67,600 25,000 9,100 4,410 3,280 110,900 39,300 12,400 7,480 5,550 90,800 29,900 9,400 6,150 4,350

R 94,100 47,500 14,300 6,830 3,100 110,200 48,400 21,000 11,600 6,720 103,300 46,000 19,600 9,760 5,300

151 07299200

U 8.41 0.83 0.11 0.00 0.00 76.0 2.27 0.46 0.25 0.07 151 7.82 0.37 0.09 0.03

152 07299300

U 1.67 0.19 0.08 0.04 0.01 4.54 0.35 0.09 0.03 0.01 5.14 0.50 0.11 0.05 0.02

153 07299540

U 55.6 12.0 2.80 1.49 1.00 165 17.7 2.29 1.11 0.55 281 32.2 2.63 0.97 0.31

154 07299570

U 48.5 5.48 1.70 0.99 0.25 142 11.7 1.14 0.46 0.21 324 46.9 2.66 0.39 0.05

155 07299670

U 20.2 7.85 3.12 1.95 1.38 23.4 9.24 3.97 2.24 1.68 25.8 10.8 3.81 1.71 1.13
Tables 97

Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type of 

record

Monthly flow-duration statistics

APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95

156 07299890 U 5.92 3.70 2.07 1.70 1.52 4.49 2.53 1.16 0.84 0.65 3.57 1.15 0.40 0.07 0.00157 07300500 U 93.0 26.5 2.99 0.00 0.00 174 34.0 2.48 0.00 0.00 161 35.9 2.59 0.00 0.00158 07301110 U 238 89.0 39.8 22.9 15.3 477 106 37.9 16.2 7.98 505 124 48.5 24.9 14.3159 07301300 U 45.8 5.18 0.00 0.00 0.00 67.6 3.78 0.00 0.00 0.00 56.2 1.11 0.00 0.00 0.00160 07301410 U 23.7 15.5 11.1 9.25 8.32 26.6 13.7 7.35 5.42 4.29 24.0 10.3 4.47 2.67 1.91161 07301420 U 47.0 27.0 19.1 16.5 13.5 50.6 24.5 14.4 11.0 8.36 45.3 22.0 11.8 4.99 2.75

162 07301500 U 189 69.0 20.0 5.03 0.00 333 92.6 19.7 5.37 0.00 340 84.7 12.5 0.98 0.00163 07303000 R 18.7 0.58 0.07 0.00 0.00 24.6 0.78 0.00 0.00 0.00 219 1.11 0.00 0.00 0.00164 07303400 U 47.1 21.4 12.0 8.67 6.15 72.9 23.4 10.0 6.32 3.91 72.1 24.3 9.24 4.57 2.03165 07303500 U 82.6 26.8 10.2 5.07 3.01 184 44.1 12.3 6.88 3.50 189 42.7 10.7 4.25 2.22166 07304500 U 36.5 10.5 2.72 0.61 0.23 116 18.7 4.42 2.43 0.08 140 23.5 2.68 0.63 0.09

R 58.7 18.8 8.21 6.04 1.88 178 34.8 7.50 3.97 1.66 166 41.3 11.4 4.95 1.84

167 07305000 R 289 78.0 29.1 13.8 6.33 689 142 41.1 22.3 8.72 944 204 52.4 23.9 8.52

168 07305500 R 0.00 0.00 0.00 0.00 0.00 0.58 0.00 0.00 0.00 0.00 2.46 0.00 0.00 0.00 0.00

169 07307028 R 604 177 88.1 58.0 45.7 1,010 225 82.8 61.4 49.1 1,580 437 123 75.8 51.5

170 07308500 U 983 337 129 73.9 40.9 2,420 542 146 83.7 51.7 3,790 1,050 304 162 78.9

171 07311000 U 181 45.4 15.5 10.6 7.68 575 89.5 25.7 11.7 5.59 339 80.1 28.6 15.6 6.84

R 297 62.9 31.5 24.2 19.9 426 80.6 34.8 24.3 18.3 603 69.7 28.1 21.2 16.5

172 07311200 R 19.5 5.44 1.29 0.49 0.12 24.5 5.37 1.19 0.57 0.26 18.6 2.87 0.32 0.03 0.00

173 07311500 U 58.1 6.43 1.70 0.33 0.03 250 19.0 2.98 0.99 0.11 251 18.7 2.60 0.81 0.00

174 07313000 U 23.1 11.8 4.50 2.58 1.60 106 24.1 8.08 2.70 0.37 63.1 14.1 4.07 1.20 0.36

175 07313500 U 84.6 27.1 5.10 1.87 0.38 233 41.5 6.13 1.66 0.45 138 24.9 3.03 0.23 0.00

R 253 1.17 0.00 0.00 0.00 435 3.60 0.00 0.00 0.00 1,250 23.3 0.00 0.00 0.00

176 07315500 R 2,580 675 294 211 159 7,680 1,630 481 342 256 7,780 2,240 638 392 292

177 07315700 U 147 27.2 3.63 0.85 0.09 281 36.0 4.18 1.37 0.39 269 38.2 4.48 1.17 0.00178 07316000 R 3,480 1,050 407 276 207 9,270 2,090 643 460 327 10,100 2,820 962 567 373

179 07316500 U 47.8 21.4 7.35 3.09 0.54 77.4 25.4 5.34 1.12 0.00 71.5 20.1 1.32 0.00 0.00
98 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95 180 07319500

U 3.73 1.72 0.83 0.25 0.11 6.02 2.01 0.92 0.25 0.00 6.83 2.16 0.63 0.14 0.04

181 07323000

U 6.55 2.98 0.95 0.28 0.11 11.2 3.59 1.11 0.12 0.00 10.6 3.48 0.63 0.25 0.00

182 07324200

U 114 43.2 17.6 6.73 0.19 214 49.5 18.5 5.43 0.34 201 64.9 8.53 1.95 0.01

183 07324400

R 115 8.92 4.34 2.91 1.99 193 10.3 4.97 3.13 1.68 295 12.4 5.70 4.06 1.76

184 07325000

U 146 35.8 11.6 2.63 1.10 520 107 25.9 16.6 9.77 417 132 18.5 5.10 1.39

R 196 42.8 20.6 12.9 8.89 372 50.9 20.7 13.3 7.98 432 74.2 21.0 12.9 8.20

185 07325500

U 472 146 66.6 42.4 24.1 990 224 90.1 57.1 38.4 1,190 327 93.4 49.3 33.0

186 07325800

U 27.9 18.9 12.1 9.72 7.74 43.9 19.6 11.5 8.79 6.78 42.5 18.3 9.11 6.46 4.62

187 07326000

U 57.5 34.2 25.1 21.8 20.1 79.0 33.8 21.0 16.4 13.4 63.7 29.5 15.3 9.80 6.55

R 5.45 3.50 2.64 2.31 2.02 13.2 3.67 2.59 2.08 1.77 159 3.98 2.59 2.00 1.68

188 07326500

R 678 244 121 82.3 56.0 1,190 305 143 98.5 68.2 1,780 474 148 87.6 57.8

189 07327000

U 23.8 11.3 4.50 1.57 0.33 24.2 7.48 2.44 0.94 0.12 24.8 7.08 1.29 0.05 0.03

190 073274406

U 2.00 0.90 0.44 0.21 0.15 2.25 0.87 0.28 0.16 0.04 2.60 0.79 0.19 0.00 0.00

191 07327442

U 9.04 3.91 1.40 0.96 0.45 7.88 4.16 0.92 0.50 0.31 8.83 2.75 0.65 0.35 0.05

192 07327447

U 40.7 16.6 8.38 5.86 4.25 43.0 19.1 6.39 4.44 3.14 43.3 18.4 5.11 2.96 0.51

193 07327490

U 43.4 24.0 13.2 10.5 8.41 74.9 26.7 13.4 8.44 5.55 60.8 21.0 7.88 4.00 2.20

194 07327550

U 101 45.4 26.0 15.9 11.5 114 45.4 17.3 12.0 8.91 124 47.2 15.6 6.34 3.00

195 07328000

U 1,070 337 185 146 107 2,660 633 269 192 160 2,730 967 243 154 113

196 07328070

U 14.6 6.14 2.90 2.15 1.73 23.0 8.10 3.22 2.00 1.17 21.8 6.88 1.89 0.95 0.56

197 07328100

R 1,020 411 180 123 84.9 1,790 541 221 150 103 2,230 790 275 123 90.3

198 07328180

U 5.60 1.42 0.43 0.21 0.05 5.46 1.84 0.46 0.00 0.00 5.14 1.51 0.22 0.00 0.00

199 07328500

U 1,050 423 189 130 93.3 4,050 988 340 178 127 3,110 987 355 194 123

R 1,490 567 224 135 80.5 2,240 722 295 188 134 2,990 1,000 358 190 118

200 07329000

U 76.7 28.8 13.4 9.52 6.17 157 40.8 16.0 9.20 5.68 117 36.2 12.9 6.48 3.29

201 07329500

U 51.0 22.5 7.52 4.82 2.94 98.8 26.7 7.34 2.47 1.11 84.0 19.9 5.01 1.25 0.00

202 07329700

R 386 102 23.2 9.04 6.24 661 143 48.0 24.4 14.5 657 116 37.5 19.9 8.07

203 07329852

U 79.0 34.8 17.7 9.85 6.28 70.0 29.4 12.6 8.38 5.36 58.9 21.8 9.85 6.89 5.07
Tables 99

Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx 

percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type of 

record

Monthly flow-duration statistics

APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95

204 07329900 U 82.5 42.2 10.0 7.12 5.66 121 34.1 16.1 11.9 9.01 55.2 20.5 6.49 4.40 3.84205 07330500 U 256 49.5 16.0 8.70 6.60 241 58.3 19.0 7.78 2.30 165 38.0 8.64 4.56 2.22206 07331000 U 2,040 773 363 241 173 6,540 1,770 598 355 221 4,760 1,460 537 355 224

R 2,980 1,160 410 253 163 5,040 1,480 505 314 232 5,280 1,780 548 296 185

207 07331600 U 8,500 2,970 1,300 863 648 21,000 5,730 2,420 1,680 1,290 15,200 5,140 2,050 1,330 1,040

R 7,350 2,900 888 283 105 9,810 3,390 1,130 294 132 16,500 4,610 1,950 985 217

208 07332400 U 216 103 56.4 43.9 29.8 250 108 60.4 49.0 42.5 208 107 50.5 39.5 34.2209 07332500 U 469 162 82.0 56.6 39.7 524 173 78.1 57.2 44.0 356 133 55.5 41.2 31.6210 07332600 U 38.2 12.7 4.01 2.01 0.88 49.3 12.5 4.32 2.33 0.91 20.3 4.76 0.71 0.07 0.00

211 07333500 U 46.0 10.7 2.84 1.10 0.56 31.7 4.48 1.15 0.45 0.31 5.60 1.11 0.13 0.00 0.00

212 07333800 U 136 26.5 6.14 2.75 1.26 96.9 16.4 3.91 1.99 0.99 25.9 4.51 0.40 0.00 0.00213 07334000 U 2,220 322 70.9 35.7 22.7 2,590 367 78.7 46.0 29.0 826 104 27.3 13.0 7.02

R 2,100 512 96.3 50.0 34.8 1,970 436 55.0 37.5 29.8 1,490 240 42.2 28.5 21.6

214 07335000 U 905 207 77.3 45.3 23.8 1,350 266 79.1 51.3 36.3 707 138 41.2 24.1 15.7215 07335300 R 5,200 1,330 383 228 159 5,570 1,350 259 180 142 3,700 815 198 121 93.5

216 07335400 R 291 122 1.50 0.00 0.00 361 138 5.64 0.00 0.00 454 122 1.24 0.00 0.00217 07335500 R 17,500 6,670 2,680 1,710 1,270 26,500 7,870 3,090 2,150 1,530 33,300 7,890 2,950 2,140 1,640

218 07335700 U 151 62.8 26.4 17.0 11.7 147 46.1 14.3 7.78 4.60 70.8 13.9 2.79 1.18 0.33219 07335790 R 2,470 764 200 133 89.3 2,520 473 97.8 56.7 38.5 1,640 233 41.3 19.6 11.2

220 07336000 U 149 29.3 7.15 3.88 2.03 98.7 19.3 4.10 1.64 0.91 21.0 3.29 0.45 0.01 0.00221 07336200 U 2,320 822 350 265 223 3,840 949 293 173 117 2,160 477 133 58.7 24.0

R 3,840 1,170 291 186 136 3,950 903 159 84.0 54.4 2,240 469 94.2 45.8 25.3

222 07336500 U 4,110 1,160 360 226 163 4,090 943 313 196 134 1,010 259 72.0 35.4 20.5223 07336750 U 49.6 11.4 1.70 0.52 0.31 65.2 5.86 0.68 0.10 0.01 13.7 1.06 0.10 0.00 0.00224 07336800 U 127 13.2 1.13 0.39 0.18 57.0 9.46 0.71 0.04 0.00 14.4 1.10 0.00 0.00 0.00225 07336820 R 28,500 12,400 4,670 2,870 2,080 38,100 13,300 4,880 3,600 2,960 47,700 16,000 3,950 2,580 2,090
100 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 5. April, May, and June flow-duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; APRDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics APRD20 APRD50 APRD80 APRD90 APRD95 MAYD20 MAYD50 MAYD80 MAYD90 MAYD95 JUND20 JUND50 JUND80 JUND90 JUND95 226 07337500

U 1,990 596 208 133 92.2 2,560 597 197 122 85.4 320 91.8 33.5 17.4 11.1

R 2,410 410 113 40.9 27.0 2,880 508 72.0 27.7 19.1 2,400 166 25.8 17.8 13.4

227 07337900

U 711 249 105 71.1 54.6 880 254 73.4 40.1 24.2 418 86.6 23.4 10.5 5.70

228 07338500

U 4,620 1,290 462 289 177 5,930 1,140 368 228 154 888 249 86.1 50.4 31.4

R 4,400 1,030 331 213 160 5,310 1,630 276 148 108 3,630 433 108 69.1 52.0

229 07338750

U 685 324 166 126 106 628 206 102 74.8 52.9 475 130 44.4 23.1 16.4

230 07339000

U 2,920 1,020 401 259 174 2,970 739 258 156 110 666 196 57.3 30.4 19.9

R 3,270 1,030 213 141 113 3,330 819 236 168 134 2,310 720 284 197 164

231 07339500

U 689 179 62.2 39.9 26.1 497 124 37.5 21.9 15.3 116 28.0 6.59 3.98 3.15

232 07340300

U 274 125 68.2 51.2 39.4 267 85.4 41.7 31.0 24.8 138 45.1 22.2 16.6 13.5

233 07340500

U 1,370 455 172 118 87.9 1,090 291 105 71.2 52.5 325 90.3 32.2 20.9 14.9

234 07341000

U 416 140 49.1 31.8 21.4 342 95.1 30.0 18.1 12.6 100 22.2 5.65 2.83 1.52

235 07341200

U 750 170 54.7 34.2 19.8 497 157 50.9 29.5 21.2 276 52.8 8.25 3.45 2.47
Tables 101

Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded 

xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type 

of 

record

Monthly flow-duration statistics

JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95

1 07146500 U 2,500 975 279 149 106 1,490 669 224 118 73.2 1,370 464 208 146 111

R 3,760 1,190 526 365 265 2,400 842 373 264 148 2,250 758 326 233 148

2 07148140 R 7,860 2,950 752 305 199 3,050 762 281 200 163 2,810 504 177 140 122

3 07148350 U 83.8 12.1 0.71 0.21 0.00 43.4 2.35 0.19 0.00 0.00 55.6 3.28 0.20 0.00 0.00

4 07148400 U 149 39.0 4.68 1.36 0.04 94.5 23.2 2.35 0.65 0.04 75.3 11.0 1.83 0.79 0.04

5 07149000 U 126 43.3 13.2 3.71 0.24 105 23.2 1.59 0.00 0.00 95.5 31.1 4.91 0.00 0.00

6 07149500 U 388 53.2 3.29 0.05 0.02 305 24.7 0.03 0.02 0.01 186 28.5 0.03 0.01 0.01

7 07150500 R 612 114 18.5 7.98 4.86 255 29.8 8.87 5.78 4.32 347 43.4 10.5 5.38 3.09

8 07151000 R 1,230 273 83.3 54.7 26.2 622 129 50.9 32.5 21.1 644 133 46.0 28.2 15.3

9 07151500 U 255 69.4 25.3 11.5 1.66 147 39.1 13.1 6.41 0.78 169 57.1 12.6 4.88 0.05

10 07152000 U 419 131 37.6 12.3 4.57 242 65.5 19.6 6.46 2.51 253 86.1 13.5 5.04 2.09

11 07152500 U 7,310 2,570 903 455 294 3,990 1,570 605 314 143 5,180 1,610 608 321 164

R 12,700 4,700 1,600 1,070 762 7,470 2,380 620 375 295 4,930 1,700 499 361 231

12 07153000 U 108 16.7 3.68 0.92 0.36 46.5 8.03 1.27 0.22 0.01 65.0 8.00 1.33 0.17 0.00

13 07153100 R 0.69 0.03 0.01 0.01 0.00 0.04 0.03 0.01 0.01 0.00 0.05 0.03 0.01 0.01 0.00

14 07154500 U 24.4 2.72 0.05 0.02 0.01 31.5 4.32 0.56 0.03 0.02 6.61 1.35 0.04 0.02 0.01

UI 2.98 0.00 0.00 0.00 0.00 5.52 0.17 0.00 0.00 0.00 2.41 0.00 0.00 0.00 0.00

15 07155000 U 66.3 5.38 0.04 0.02 0.01 111 14.1 0.05 0.02 0.01 13.2 0.04 0.02 0.01 0.00

16 07155590 U 0.02 0.00 0.00 0.00 0.00 6.77 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

17 07156900 U 72.2 44.5 35.7 31.3 28.2 75.2 54.0 38.0 31.6 27.9 73.0 54.4 40.2 30.2 26.3

UI 33.8 25.8 19.8 17.7 16.5 32.4 25.2 20.4 18.2 17.0 32.0 26.9 22.2 20.3 19.2

18 07157000 U 108 44.7 24.0 17.4 13.2 108 45.1 21.9 15.0 8.87 78.7 47.8 24.8 17.4 12.4

19 07157500 U 53.6 9.89 0.04 0.02 0.01 35.5 7.54 0.04 0.02 0.01 28.2 5.98 0.03 0.01 0.01

UI 11.5 4.92 2.16 1.05 0.46 11.9 4.13 1.45 0.64 0.22 8.27 4.07 1.80 0.96 0.56

20 07157900 U 1.84 0.96 0.51 0.37 0.27 1.70 0.98 0.54 0.29 0.16 1.89 1.05 0.74 0.60 0.42

21 07157950 U 93.1 8.72 0.00 0.00 0.00 54.6 4.57 0.00 0.00 0.00 84.3 2.47 0.00 0.00 0.00

22 07157960 U 4.99 0.79 0.00 0.00 0.00 5.79 0.22 0.00 0.00 0.00 5.34 0.18 0.00 0.00 0.00
102 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95 23 07158000

U 280 51.4 0.71 0.00 0.00 176 26.8 0.00 0.00 0.00 169 15.7 0.00 0.00 0.00

24 07158400

U 13.1 6.24 2.44 1.14 0.55 12.4 4.89 2.67 1.75 1.18 15.3 6.49 3.36 2.52 1.85

25 07159000

U 14.3 1.51 0.00 0.00 0.00 8.00 0.83 0.00 0.00 0.00 9.47 0.42 0.00 0.00 0.00

26 07159100

U 714 211 79.5 55.0 42.0 509 162 48.1 30.5 21.1 518 129 41.5 27.7 16.9

27 07159750

U 90.2 46.7 25.3 19.0 15.2 71.7 33.5 18.3 14.4 12.1 111 37.7 20.4 15.8 12.9

28 07160000

U 1,300 380 168 120 89.1 917 328 111 71.4 49.4 1,000 311 109 80.6 64.2

29 07160350

U 26.9 10.8 6.20 4.37 3.60 16.1 7.83 4.65 3.67 3.04 13.2 7.54 4.69 3.47 2.87

30 07160500

U 64.5 15.7 5.48 2.80 1.35 37.3 11.0 4.38 3.03 1.86 51.0 11.4 4.38 2.59 1.08

31 07163000

U 1.26 0.11 0.00 0.00 0.00 0.48 0.00 0.00 0.00 0.00 0.90 0.00 0.00 0.00 0.00

32 07163500

U 1,350 451 180 120 75.2 700 292 70.5 23.2 10.1 1,500 256 59.1 22.5 11.5

33 07164000

U 2,700 906 373 254 172 1,440 421 145 78.0 59.8 1,720 424 103 68.1 39.5

34 07164500

U 12,200 4,190 1,210 627 389 6,370 2,360 824 380 190 7,590 2,340 794 454 208

R 16,200 6,810 2,790 1,560 1030 8,980 3,400 1,400 876 444 7,990 2,940 1,060 475 239

35 07164600 UUrb 9.19 2.48 1.36 1.04 0.82 4.80 1.78 1.16 0.95 0.83 6.87 1.79 0.94 0.73 0.56

36 07165500

R 18.6 0.87 0.00 0.00 0.00 9.03 0.24 0.00 0.00 0.00 20.2 0.38 0.00 0.00 0.00

37 07165562 UUrb 6.07 0.96 0.02 0.00 0.00 2.82 0.41 0.00 0.00 0.00 5.08 0.65 0.00 0.00 0.00

38 07165565 UUrb 3.38 0.66 0.05 0.00 0.00 1.26 0.21 0.00 0.00 0.00 2.63 0.41 0.00 0.00 0.00

39 07165570

R 18,500 7,770 3,230 2,000 1390 11,500 4,270 1,430 958 685 9,150 3,190 1,180 774 574

40 07170500

U 1,240 266 26.9 7.88 2.14 398 69.5 15.0 3.95 0.90 617 67.2 15.5 4.25 0.77

R 3,320 335 75.0 41.5 26.1 624 99.2 39.1 26.8 20.2 897 86.9 37.2 26.1 17.5

41 07170700

U 3.26 0.35 0.00 0.00 0.00 0.60 0.00 0.00 0.00 0.00 3.23 0.01 0.00 0.00 0.00

R 9.82 0.20 0.00 0.00 0.00 0.42 0.02 0.00 0.00 0.00 0.59 0.02 0.00 0.00 0.00

42 07171000

U 2,950 312 34.1 15.5 7.95 545 91.4 8.26 3.30 2.06 968 78.4 10.1 1.10 0.10

R 3,880 444 91.1 51.8 26.3 838 120 42.4 28.3 19.2 1,240 115 38.3 25.8 17.1

43 07171400

R 4,420 723 59.6 32.4 12.1 888 92.0 31.2 10.5 3.15 1,420 77.9 13.2 5.17 1.59

44 07172000

U 105 23.4 3.87 0.51 0.00 33.0 6.37 0.26 0.00 0.00 49.7 5.82 0.12 0.00 0.00

45 07173000

U 172 22.9 10.9 5.57 2.84 38.0 16.9 7.92 3.90 1.37 52.7 14.8 8.06 3.34 1.90
Tables 103

Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded 

xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type 

of 

record

Monthly flow-duration statistics

JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95

46 07174200 U 81.8 10.7 1.42 0.10 0.00 18.7 2.57 0.09 0.00 0.00 50.6 2.97 0.17 0.00 0.00

47 07174400 R 2,580 96.6 32.7 25.6 21.7 81.8 38.2 26.0 19.5 14.6 78.3 32.6 19.0 14.3 11.5

48 07174600 U 10.7 2.44 0.09 0.00 0.00 3.89 0.28 0.00 0.00 0.00 15.3 0.64 0.00 0.00 0.00

49 07174700 R 609 54.6 24.7 17.0 12.5 84.5 31.7 18.2 14.6 10.8 343 49.5 18.6 12.8 7.88

50 07175000 U 0.21 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

51 07175500 R 2,870 231 48.9 36.6 29.1 196 64.5 41.3 34.8 28.5 223 58.2 36.9 29.3 23.3

52 07176000 U 4,990 474 83.1 29.7 16.1 1,170 147 19.9 6.39 0.04 2,360 150 25.6 3.54 0.03

R 8,270 1,540 127 78.0 60.0 1,440 164 76.5 56.3 40.9 1,750 157 63.7 46.4 34.3

53 07176465 R 18.1 8.02 4.52 3.71 1.32 9.36 5.48 3.12 1.59 1.24 8.54 5.15 3.27 1.63 1.27

54 07176500 U 73.7 6.39 0.12 0.00 0.00 24.6 1.20 0.00 0.00 0.00 62.3 3.34 0.00 0.00 0.00

R 148 32.7 15.7 10.2 5.79 49.4 21.2 8.37 5.65 4.44 50.4 21.0 7.76 5.10 4.00

55 07176800 U 0.68 0.00 0.00 0.00 0.00 0.25 0.00 0.00 0.00 0.00 3.90 0.02 0.00 0.00 0.00

56 07177000 U 49.9 8.15 1.06 0.00 0.00 17.1 2.76 0.10 0.00 0.00 33.5 3.38 0.18 0.00 0.00

57 07177500 U 148 31.5 8.17 2.57 0.75 61.0 13.5 3.34 1.12 0.04 115 15.0 2.97 0.55 0.04

R 513 189 154 118 60.6 222 172 129 34.6 17.4 214 170 128 66.0 19.0

58 07177650 UUrb 0.88 0.20 0.02 0.00 0.00 0.38 0.09 0.00 0.00 0.00 0.62 0.22 0.01 0.00 0.00

59 07177800 UUrb 4.72 1.27 0.41 0.23 0.14 3.33 1.12 0.26 0.12 0.00 3.71 0.82 0.33 0.19 0.13

60 07178000 R 785 216 171 159 153 257 184 159 151 124 276 194 162 151 125

61 07178040 UUrb 35.6 7.21 2.77 2.10 1.55 18.9 3.92 2.13 1.69 1.46 45.2 8.34 2.65 2.02 1.51

62 07178200 R 1,200 281 205 182 171 406 252 195 178 169 464 265 202 181 170

63 07178600 U 11,700 870 131 53.3 35.3 1,850 251 50.7 26.2 15.4 2,590 208 54.7 24.1 13.1

64 07184000 U 33.9 4.62 0.39 0.03 0.00 8.79 0.97 0.02 0.00 0.00 21.6 0.83 0.00 0.00 0.00

65 07185000 U 6,510 992 218 73.7 29.3 1,710 409 90.6 9.49 0.05 3,880 342 48.4 1.61 0.03

R 7,610 1,510 286 146 85.9 2,180 386 101 64.7 45.3 2,330 353 77.8 49.0 37.1

66 07185095 UUrb 14.7 4.21 2.21 0.71 0.45 5.55 2.42 1.51 1.12 0.41 11.8 3.24 1.58 0.90 0.62

67 07185500 U 0.61 0.14 0.00 0.00 0.00 0.18 0.01 0.00 0.00 0.00 0.43 0.04 0.00 0.00 0.00

68 07185700 U 267 145 76.6 58.4 42.8 159 95.1 53.9 44.0 37.2 155 92.2 49.1 38.4 32.8
104 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95 69 07185765

U 330 177 84.3 61.2 49.3 183 118 56.5 47.0 41.0 204 115 60.7 45.7 38.9

70 07186000

U 642 247 111 72.6 53.0 295 143 72.9 49.9 33.2 328 128 69.3 46.7 33.3

71 07186400

U 134 77.3 45.6 36.3 30.8 82.1 50.6 33.8 26.0 21.7 92.5 49.5 31.6 24.2 20.1

72 07187000

U 413 229 134 108 82.6 247 154 96.0 76.9 63.7 230 138 89.7 71.0 56.7

73 07187500

U 484 213 116 71.4 54.1 407 170 102 46.6 35.0 367 168 87.8 71.1 57.1

74 07188000

U 1,760 729 347 241 178 769 431 224 162 123 1,000 409 214 153 106

75 07188500

U 45.6 20.2 6.44 2.38 1.57 21.3 10.1 3.76 1.70 1.40 18.9 7.58 3.14 1.03 0.69

76 07189000

U 513 248 131 99.8 80.0 275 149 81.9 64.5 51.6 259 131 73.8 53.6 39.6

77 07189500

U 4,910 1,600 717 361 240 3,250 1,000 487 209 74.9 3,500 1,080 426 289 165

78 07189540

U 4.48 2.87 1.90 1.68 1.57 3.08 2.30 1.83 1.65 1.56 2.98 2.32 1.92 1.71 1.59

79 07189542

U 31.0 13.4 8.56 6.87 5.80 16.0 9.20 6.76 5.35 4.17 13.1 8.37 5.62 4.69 4.33

80 07190500

R 12,700 5,000 1,600 422 79.8 6,580 3,250 880 115 39.2 7,010 2,600 344 63.3 29.0

81 07191000

U 71.5 9.72 2.59 1.57 1.11 18.3 3.95 1.47 0.93 0.72 31.3 3.41 1.21 0.79 0.50

82 07191220

U 68.5 39.6 21.0 14.1 8.80 46.2 26.5 14.0 8.90 6.41 43.7 23.9 13.4 9.93 6.45

83 07191500

R 14,600 5,670 1,130 322 221 7,930 3,350 480 239 183 7,690 2,150 289 181 147

84 07192000

U 35.5 2.64 0.04 0.02 0.01 15.3 1.38 0.04 0.02 0.01 15.1 0.31 0.03 0.01 0.01

85 07192500

R 10,800 5,090 2,370 1,370 273 5,840 3,440 2,110 1,100 87.1 5,750 3,010 1,320 954 280

86 07193500

R 12,300 5,310 1,980 733 182 5,970 3,110 813 125 16.8 7,600 3,120 508 71.0 16.4

87 07194500

U 27,400 9,370 3,510 2,250 1230 16,100 5,420 2,610 1,660 499 20,600 5,810 2,660 1,700 1,190

R 49,000 19,300 5,490 3,780 2900 19,400 8,840 4,300 2,890 2,240 21,000 9,740 4,320 2,500 1,860

88 07194800

U 61.5 20.4 11.0 7.61 5.77 24.7 13.2 8.12 6.11 2.79 21.0 12.5 8.36 7.19 5.30

89 07195000

U 135 72.6 43.4 28.7 20.2 94.4 61.4 36.1 24.8 16.8 93.5 60.5 32.8 23.9 18.3

90 07195430

U 430 228 142 120 63.5 250 170 126 109 82.4 227 166 125 106 92.3

91 07195500

U 376 210 125 91.3 70.1 264 162 103 77.5 56.7 272 150 97.2 76.3 60.1

92 07195800

U 10.6 6.20 3.92 2.64 1.91 8.78 4.91 3.09 2.25 1.69 9.12 5.17 3.07 2.16 1.76

93 07195855

R 38.1 16.4 7.95 5.43 3.58 24.2 13.1 6.06 4.11 1.45 20.0 10.3 6.11 4.32 2.75
Tables 105

Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded 

xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type 

of 

record

Monthly flow-duration statistics

JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95

94 07195865 U 20.3 9.72 6.61 5.02 4.16 11.7 7.70 5.31 4.41 3.69 10.8 7.61 5.67 4.49 3.62

95 07196000 U 76.2 37.8 22.3 17.1 12.6 52.6 29.3 16.9 12.7 10.0 53.1 27.7 17.3 13.7 11.8

96 07196500 U 586 293 158 118 81.3 380 210 119 83.5 46.7 386 193 109 74.2 46.2

97 07196900 U 12.0 3.67 1.22 0.70 0.38 5.13 1.99 0.53 0.27 0.12 7.29 1.64 0.51 0.26 0.05

98 07196973 U 16.3 6.29 0.48 0.01 0.00 5.45 1.84 0.00 0.00 0.00 4.51 0.79 0.00 0.00 0.00

99 07197000 U 167 72.6 35.9 23.1 16.3 87.6 44.6 22.4 13.2 7.13 85.8 39.4 18.3 11.3 5.14

100 07197360 U 61.0 20.0 13.8 11.5 9.22 26.4 14.5 8.48 5.48 4.24 24.4 16.9 11.1 8.57 6.60

101 07198000 U 1,460 653 337 253 189 689 350 206 168 138 708 337 190 155 136

R 1,680 868 136 97.9 76.0 1,380 719 137 93.4 69.6 1,100 354 106 70.1 41.3

102 07228500 U 698 45.9 6.75 0.05 0.02 499 36.7 3.87 0.04 0.02 266 22.7 2.72 0.04 0.02

R 177 41.5 11.1 5.45 2.29 101 19.1 5.31 2.60 0.00 130 27.5 9.02 4.53 1.30

103 07229100 R 98.4 12.7 5.06 3.68 1.87 88.6 9.14 4.55 2.87 2.39 189 61.2 7.50 5.22 4.29

104 07229200 R 545 203 59.8 34.7 8.57 362 83.5 19.7 9.98 2.45 420 131 28.5 12.0 3.86

105 07229300 U 44.1 15.8 1.16 0.51 0.32 30.5 9.46 0.79 0.30 0.17 37.3 10.4 1.18 0.37 0.20

106 07230000 U 28.6 7.80 0.48 0.19 0.13 12.1 3.60 0.33 0.11 0.03 12.2 3.04 0.20 0.11 0.03

R 1.14 0.70 0.41 0.26 0.19 1.01 0.67 0.39 0.29 0.20 0.97 0.65 0.39 0.25 0.18

107 07230500 U 90.1 22.6 1.88 0.03 0.02 29.1 9.94 1.22 0.03 0.02 27.8 7.50 0.54 0.03 0.02

R 56.0 11.4 2.70 0.38 0.00 18.2 5.20 0.61 0.00 0.00 27.9 6.38 0.98 0.00 0.00

108 07231000 U 395 64.6 17.0 6.33 3.31 102 26.5 5.45 1.18 0.04 84.9 19.5 4.32 0.12 0.03

R 165 29.7 4.47 1.28 0.17 45.2 10.0 0.86 0.01 0.00 98.3 12.6 0.84 0.07 0.00

109 07231500 U 3,190 472 57.0 14.7 5.88 1,670 275 28.0 4.40 0.29 1,500 155 12.6 0.29 0.03

R 1,010 214 41.4 18.0 6.26 468 113 17.6 4.23 0.00 949 174 28.6 9.86 1.78

110 07232000 U 130 9.86 1.39 0.28 0.04 45.3 4.00 0.13 0.03 0.01 72.9 3.21 0.14 0.03 0.02

111 07232500 U 16.7 2.81 0.32 0.00 0.00 10.7 1.42 0.00 0.00 0.00 5.60 1.11 0.11 0.00 0.00

UI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

112 07232900 UI 0.00 0.00 0.00 0.00 0.00 0.08 0.05 0.02 0.01 0.01 0.08 0.05 0.02 0.01 0.01

113 07233000 U 9.44 0.19 0.02 0.01 0.01 2.42 0.04 0.01 0.01 0.00 0.05 0.03 0.01 0.01 0.00
106 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95 114 07233500

U 19.9 2.16 0.00 0.00 0.00 7.75 1.44 0.00 0.00 0.00 5.38 0.49 0.00 0.00 0.00

115 07233650

R 0.45 0.05 0.00 0.00 0.00 0.25 0.03 0.00 0.00 0.00 0.36 0.07 0.00 0.00 0.00

116 07234000 RI 13.2 0.30 0.00 0.00 0.00 1.86 0.05 0.00 0.00 0.00 0.39 0.01 0.00 0.00 0.00

U 130 17.7 0.00 0.00 0.00 67.2 1.42 0.00 0.00 0.00 23.9 0.00 0.00 0.00 0.00

117 07234100

U 2.47 1.46 1.02 0.71 0.39 2.22 1.33 0.90 0.71 0.48 2.45 1.57 1.02 0.76 0.55

118 07234500

U 244 41.7 0.05 0.02 0.01 121 8.38 0.03 0.01 0.01 95.6 0.05 0.02 0.01 0.00

119 07235000

R 7.65 1.66 0.34 0.03 0.00 6.49 0.65 0.14 0.08 0.00 9.92 2.50 0.72 0.34 0.00

RI 6.22 2.28 0.70 0.46 0.28 2.59 1.06 0.53 0.38 0.26 1.77 0.78 0.47 0.36 0.27

120 07236000

U 92.1 24.1 1.09 0.04 0.02 35.6 5.72 0.03 0.02 0.01 22.1 2.83 0.02 0.01 0.01

121 07237000

R 31.2 2.05 0.59 0.35 0.15 5.16 1.27 0.45 0.14 0.03 3.75 1.19 0.48 0.05 0.02

RI 34.5 5.18 1.50 1.20 0.94 7.24 1.83 0.99 0.81 0.73 6.42 1.88 0.82 0.65 0.55

122 07237500

U 363 55.1 0.40 0.00 0.00 116 12.5 0.00 0.00 0.00 84.6 3.66 0.00 0.00 0.00

RI 148 50.0 14.2 5.71 3.70 58.6 22.0 8.87 3.21 1.97 43.9 13.6 4.44 2.68 1.49

123 07238000

U 449 81.5 0.59 0.00 0.00 145 14.9 0.00 0.00 0.00 103 11.3 0.00 0.00 0.00

RI 206 75.0 22.1 8.60 4.12 82.1 36.7 8.58 1.91 0.68 64.1 21.1 6.30 0.86 0.13

124 07239000

U 274 40.1 0.05 0.02 0.01 71.9 1.07 0.02 0.01 0.01 93.4 0.04 0.02 0.01 0.00

R 297 22.4 5.52 3.00 1.90 48.9 14.1 4.28 2.74 1.90 47.9 12.0 4.30 2.64 1.79

125 07239300

R 472 46.4 19.7 11.9 8.79 215 37.7 20.8 11.7 6.85 127 32.5 12.3 7.90 5.37

126 07239450

R 573 72.8 32.3 16.5 10.5 316 49.9 25.5 13.3 6.52 231 40.8 17.2 10.8 5.70

127 07239500

U 429 116 25.2 6.52 0.71 267 34.9 1.02 0.03 0.01 138 11.8 0.03 0.01 0.01

R 456 67.0 15.2 4.63 0.64 168 32.2 4.09 0.00 0.00 185 30.2 2.96 0.00 0.00

128 07241000

R 238 14.2 2.50 1.14 0.33 102 7.57 1.58 0.55 0.00 89.8 11.0 1.81 0.45 0.00

129 07241500

R 650 119 47.2 37.6 32.3 145 51.8 35.2 30.6 28.3 96.0 41.0 30.0 26.4 23.9

130 07241520

R 740 215 62.0 41.3 29.9 431 139 56.0 35.0 24.0 396 132 51.8 41.6 28.9

131 07241550

R 621 207 104 80.5 70.2 338 149 79.7 62.0 54.7 375 162 88.7 66.0 57.9

132 07242000

R 1,050 360 150 84.3 50.7 485 202 87.8 52.3 34.9 555 200 75.8 46.9 27.2

133 07242350 UUrb 43.1 28.5 14.4 9.72 8.00 41.9 25.8 11.6 7.33 5.86 38.0 26.0 11.4 6.68 3.26
Tables 107

Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded 

xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type 

of 

record

Monthly flow-duration statistics

JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95

134 07242380 R 310 47.1 24.6 19.4 16.0 171 29.3 18.9 14.4 12.3 192 43.3 17.5 12.1 10.4

135 07243000 U 5.67 2.08 0.00 0.00 0.00 2.03 0.36 0.00 0.00 0.00 4.00 0.26 0.00 0.00 0.00

136 07243500 U 729 152 46.0 28.6 18.7 247 66.6 21.1 10.5 5.50 364 67.4 15.7 7.02 3.19

137 07244000 U 1,790 276 83.4 57.2 47.1 344 80.1 29.8 18.9 13.9 372 56.3 22.3 12.6 7.61

138 07245000 U 9,360 2,670 610 238 122 3,370 1,040 272 148 57.0 4,110 671 164 56.8 12.7

R 7,580 3,920 1,020 306 134 5,510 3,100 768 228 113 3,750 1,250 215 108 80.0

139 07245500 U 73.3 17.9 3.92 1.22 0.32 26.0 7.45 1.23 0.27 0.19 31.6 5.81 1.03 0.21 0.15

140 07247000 U 32.8 5.28 1.44 0.54 0.10 12.7 2.89 0.46 0.07 0.00 14.8 2.86 0.41 0.00 0.00

141 07247015 U 46.4 13.0 3.21 1.78 0.95 7.70 3.89 2.19 1.44 0.50 27.5 4.36 1.51 0.98 0.56

142 07247250 U 28.5 5.88 0.93 0.28 0.00 3.91 0.77 0.00 0.00 0.00 5.35 0.25 0.00 0.00 0.00

143 07247500 U 20.6 3.26 0.45 0.10 0.00 8.26 1.85 0.08 0.00 0.00 19.4 2.62 0.08 0.00 0.00

144 07248500 U 136 47.4 18.9 8.93 4.71 126 21.1 2.07 0.61 0.04 88.0 18.8 0.86 0.30 0.03

R 250 24.5 8.61 4.11 1.66 106 17.6 8.00 4.55 1.14 105 15.0 7.19 4.07 0.85

145 07249400 U 28.9 7.98 2.48 1.04 0.55 11.0 3.96 1.00 0.24 0.04 14.8 3.89 0.97 0.31 0.00

146 07249413 R 668 97.8 32.4 23.1 15.8 181 41.8 21.3 16.9 12.4 336 70.1 23.3 17.9 13.8

147 07249500 U 8.32 1.38 0.40 0.12 0.10 3.46 0.82 0.11 0.04 0.02 4.65 0.92 0.11 0.04 0.02

148 07249985 U 91.6 19.9 5.18 2.10 0.94 32.8 6.70 1.26 0.04 0.00 44.5 5.77 0.41 0.00 0.00

149 07250000 U 77.9 18.3 4.17 1.50 0.69 34.4 6.72 1.10 0.00 0.00 50.3 6.07 0.41 0.00 0.00

150 07250550 U 53,700 14,800 5,470 3,190 2330 20,700 8,260 3,930 2,390 1,060 25,600 8,020 3,350 1,590 962

R 50,600 23,800 10,900 6,310 2970 25,100 12,900 6,070 3,560 1,580 25,000 9,850 3,560 1,550 460

151 07299200 U 27.5 1.07 0.09 0.00 0.00 44.0 1.54 0.04 0.00 0.00 50.3 2.57 0.14 0.03 0.00

152 07299300 U 1.15 0.17 0.05 0.00 0.00 2.84 0.22 0.01 0.00 0.00 9.78 0.58 0.10 0.02 0.00

153 07299540 U 59.5 4.83 0.79 0.32 0.11 87.2 5.15 0.97 0.36 0.11 113 9.98 1.72 0.82 0.38

154 07299570 U 68.1 3.61 0.10 0.00 0.00 52.5 2.24 0.06 0.00 0.00 98.9 10.1 0.63 0.04 0.00

155 07299670 U 17.6 7.51 2.36 0.60 0.02 18.0 6.98 1.77 0.26 0.00 21.1 8.05 2.51 0.93 0.37

156 07299890 U 1.28 0.59 0.03 0.00 0.00 1.06 0.43 0.03 0.00 0.00 1.18 0.64 0.31 0.14 0.00

157 07300500 U 43.5 3.38 0.00 0.00 0.00 17.9 0.00 0.00 0.00 0.00 28.7 0.42 0.00 0.00 0.00
108 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95 158 07301110

U 184 81.1 29.5 11.7 7.45 177 84.7 31.3 13.3 6.92 138 54.2 16.9 9.09 3.30

159 07301300

U 0.82 0.00 0.00 0.00 0.00 0.14 0.00 0.00 0.00 0.00 2.70 0.00 0.00 0.00 0.00

160 07301410

U 7.95 2.74 0.75 0.36 0.21 4.08 1.05 0.29 0.14 0.05 6.67 1.35 0.38 0.15 0.03

161 07301420

U 17.2 8.56 2.47 1.06 0.62 10.0 2.38 0.72 0.36 0.15 13.3 2.95 0.62 0.33 0.16

162 07301500

U 89.6 12.8 0.00 0.00 0.00 35.2 0.01 0.00 0.00 0.00 40.5 0.61 0.00 0.00 0.00

163 07303000

R 2.17 0.44 0.00 0.00 0.00 1.22 0.24 0.00 0.00 0.00 1.19 0.24 0.00 0.00 0.00

164 07303400

U 25.5 11.1 2.23 0.65 0.35 23.3 9.16 2.17 0.70 0.27 31.2 11.4 5.41 2.91 0.75

165 07303500

U 64.5 16.1 2.73 0.51 0.07 51.3 10.3 2.17 0.94 0.00 66.9 22.3 3.64 0.54 0.00

166 07304500

U 43.8 11.5 0.26 0.00 0.00 23.0 5.37 0.00 0.00 0.00 24.2 5.41 0.00 0.00 0.00

R 37.2 13.2 2.48 0.62 0.31 29.7 6.91 1.34 0.40 0.00 42.8 8.41 1.68 0.50 0.20

167 07305000

R 225 71.5 17.7 4.91 0.55 136 37.2 7.43 0.79 0.00 216 44.0 6.66 1.05 0.00

168 07305500

R 0.00 0.00 0.00 0.00 0.00 0.28 0.00 0.00 0.00 0.00 0.51 0.00 0.00 0.00 0.00

169 07307028

R 454 163 68.3 47.2 38.3 346 111 42.9 29.7 21.0 417 134 34.9 18.7 8.30

170 07308500

U 987 284 87.4 29.4 6.00 748 201 57.2 20.7 0.62 1,200 290 70.5 30.2 10.3

171 07311000

U 93.6 33.4 13.8 8.26 5.09 33.5 16.2 5.66 3.20 1.72 32.5 13.3 4.71 1.84 0.04

R 101 32.2 17.1 12.3 9.49 71.3 26.0 15.6 12.0 8.54 94.3 29.8 17.1 13.4 10.9

172 07311200

R 1.62 0.19 0.00 0.00 0.00 0.21 0.00 0.00 0.00 0.00 0.41 0.00 0.00 0.00 0.00

173 07311500

U 23.2 3.01 0.16 0.00 0.00 14.5 1.49 0.00 0.00 0.00 32.0 2.31 0.00 0.00 0.00

174 07313000

U 17.0 4.23 0.11 0.03 0.01 5.37 0.37 0.03 0.01 0.01 6.48 0.04 0.02 0.01 0.00

175 07313500

U 37.8 4.50 0.00 0.00 0.00 13.7 1.11 0.00 0.00 0.00 28.8 1.52 0.00 0.00 0.00

R 12.6 2.52 0.00 0.00 0.00 8.23 2.92 0.00 0.00 0.00 8.76 3.48 0.00 0.00 0.00

176 07315500

R 2,060 688 304 217 179 1,280 462 224 179 154 2,630 511 205 149 119

177 07315700

U 24.1 4.17 0.33 0.00 0.00 11.8 1.01 0.00 0.00 0.00 46.9 2.92 0.00 0.00 0.00

178 07316000

R 2,940 952 386 265 210 1,460 533 245 184 153 2,740 667 242 167 130

179 07316500

U 19.3 2.82 0.00 0.00 0.00 5.10 0.00 0.00 0.00 0.00 4.79 0.00 0.00 0.00 0.00

180 07319500

U 2.47 0.79 0.21 0.00 0.00 1.80 0.57 0.00 0.00 0.00 1.59 0.60 0.00 0.00 0.00
Tables 109

Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded 

xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type 

of 

record

Monthly flow-duration statistics

JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95

181 07323000 U 5.13 0.95 0.12 0.00 0.00 2.81 0.50 0.00 0.00 0.00 3.54 0.62 0.00 0.00 0.00

182 07324200 U 56.8 19.3 1.31 0.05 0.00 34.1 8.15 0.25 0.00 0.00 27.4 8.20 0.31 0.00 0.00

183 07324400 R 31.7 7.78 4.29 2.45 1.48 26.7 7.45 4.27 2.83 0.94 13.5 6.57 4.06 1.07 0.41

184 07325000 U 142 48.9 14.9 5.07 0.55 68.8 18.5 5.76 0.79 0.04 71.9 12.6 2.12 0.04 0.02

R 112 29.9 11.7 6.54 3.26 79.6 23.6 9.46 5.58 3.91 78.4 23.8 9.94 6.75 3.97

185 07325500 U 368 130 54.3 26.4 15.2 226 78.9 35.0 20.7 10.5 262 76.2 31.5 20.2 10.6

186 07325800 U 19.3 9.19 4.64 3.27 1.17 17.3 7.58 3.63 2.76 1.64 18.5 8.98 4.26 3.06 2.33

187 07326000 U 30.2 17.9 11.0 7.23 5.40 20.0 11.3 5.46 2.75 1.81 21.0 10.4 5.35 2.18 1.27

R 4.85 2.78 1.93 1.50 1.01 4.75 2.80 1.99 1.60 1.34 4.04 2.69 2.03 1.76 1.62

188 07326500 R 654 158 63.8 34.1 18.5 398 111 52.8 35.3 20.0 477 118 59.0 39.3 29.8

189 07327000 U 4.43 0.45 0.03 0.02 0.01 1.59 0.10 0.02 0.01 0.01 11.0 0.56 0.03 0.01 0.01

190 073274406 U 1.43 0.55 0.08 0.03 0.00 1.20 0.29 0.06 0.01 0.00 0.97 0.24 0.06 0.03 0.00

191 07327442 U 5.40 1.74 0.34 0.09 0.00 3.83 0.95 0.10 0.02 0.00 3.55 0.69 0.24 0.03 0.02

192 07327447 U 24.2 7.93 2.54 0.88 0.07 18.4 5.14 1.37 0.78 0.13 17.8 5.01 2.09 1.10 0.81

193 07327490 U 24.5 8.20 1.54 0.04 0.02 14.9 4.96 0.05 0.02 0.01 19.9 5.64 0.37 0.04 0.02

194 07327550 U 49.8 20.4 5.24 1.93 0.65 45.5 11.9 3.06 1.64 0.00 47.0 12.9 5.03 2.87 1.77

195 07328000 U 784 399 222 136 74.7 441 200 103 66.9 38.0 394 148 69.9 47.5 10.4

196 07328070 U 7.18 2.06 0.45 0.13 0.00 3.85 1.45 0.32 0.03 0.00 4.59 1.62 0.44 0.22 0.06

197 07328100 R 926 256 89.4 43.0 22.9 567 157 66.5 38.9 14.0 718 186 82.7 50.6 36.2

198 07328180 U 2.40 0.51 0.06 0.00 0.00 1.45 0.30 0.00 0.00 0.00 1.96 0.35 0.00 0.00 0.00

199 07328500 U 1,030 489 255 132 73.3 513 249 127 52.1 15.0 414 160 65.8 19.4 3.55

R 1,100 354 113 44.4 17.5 663 195 79.7 27.2 2.69 959 264 82.8 55.2 29.3

200 07329000 U 39.2 15.4 7.45 3.84 1.69 18.2 7.76 3.00 1.38 0.11 24.0 7.34 2.36 0.30 0.00

201 07329500 U 27.5 5.25 0.00 0.00 0.00 15.0 2.53 0.00 0.00 0.00 26.6 6.49 0.00 0.00 0.00

202 07329700 R 76.0 22.3 6.44 1.55 0.80 38.0 11.3 2.53 0.47 0.21 90.9 18.0 2.07 0.88 0.10

203 07329852 U 23.8 12.3 7.46 5.82 3.54 18.9 10.7 6.67 4.19 2.54 23.7 10.6 5.66 2.69 2.01

204 07329900 U 25.0 10.8 5.00 3.11 2.17 17.4 8.70 4.70 2.97 1.77 17.2 10.2 5.05 3.88 2.38
110 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued [Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded xx percent of the time, in cubic feet per second] Map no. USGS station ID Type of record Monthly flow-duration statistics JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95 205 07330500

U 34.3 6.25 1.89 0.85 0.29 16.3 1.08 0.04 0.02 0.01 11.8 1.40 0.03 0.02 0.01

206 07331000

U 1,400 640 274 168 107 734 339 172 86.7 38.4 1,000 292 124 45.1 14.0

R 1,760 500 162 72.0 40.8 1,080 268 106 26.8 12.6 1,660 425 127 70.9 41.9

207 07331600

U 5,480 2,070 922 549 429 3,610 1,410 587 444 298 5,450 1,750 632 418 284

R 6,260 3,820 1,880 486 160 4,580 3,030 1,580 379 181 3,840 2,270 530 181 99.0

208 07332400

U 98.2 60.1 38.8 31.4 28.1 60.5 45.4 34.5 28.6 19.8 63.4 41.6 32.3 28.5 22.8

209 07332500

U 145 70.5 33.1 22.2 15.1 85.7 46.1 25.1 15.8 4.15 98.1 41.8 23.7 15.0 3.67

210 07332600

U 3.40 0.38 0.00 0.00 0.00 0.64 0.00 0.00 0.00 0.00 4.20 0.00 0.00 0.00 0.00

211 07333500

U 2.11 0.13 0.00 0.00 0.00 0.48 0.00 0.00 0.00 0.00 2.83 0.08 0.00 0.00 0.00

212 07333800

U 7.23 0.69 0.00 0.00 0.00 5.08 0.11 0.00 0.00 0.00 12.9 0.61 0.00 0.00 0.00

213 07334000

U 117 24.1 3.87 1.22 0.40 62.4 10.1 1.04 0.10 0.00 106 11.4 1.62 0.00 0.00

R 261 42.7 20.6 17.3 15.1 88.4 24.6 16.6 13.8 12.2 208 29.0 14.9 12.8 11.7

214 07335000

U 136 40.6 14.8 6.77 1.84 50.8 20.3 7.95 3.19 0.08 104 23.9 7.68 2.17 0.00

215 07335300

R 812 185 78.0 48.8 35.4 375 102 40.4 26.1 15.7 670 130 46.0 22.1 15.6

216 07335400

R 112 23.4 0.00 0.00 0.00 9.19 0.00 0.00 0.00 0.00 6.27 0.00 0.00 0.00 0.00

217 07335500

R 8,980 4,670 2,620 1,890 1360 5,650 3,560 2,200 1,580 1,100 6,190 2,920 1,490 1,020 657

218 07335700

U 14.2 2.14 0.13 0.00 0.00 3.38 0.46 0.00 0.00 0.00 5.49 0.54 0.00 0.00 0.00

219 07335790

R 152 21.5 5.51 2.38 1.32 55.3 6.73 1.76 0.26 0.00 126 8.49 1.38 0.11 0.00

220 07336000

U 5.48 0.33 0.00 0.00 0.00 2.24 0.00 0.00 0.00 0.00 11.1 0.10 0.00 0.00 0.00

221 07336200

U 177 57.6 22.3 12.1 6.09 156 32.1 0.79 0.00 0.00 308 28.3 1.11 0.00 0.00

R 319 57.2 17.9 7.80 2.90 114 15.4 3.63 0.69 0.00 203 22.9 2.78 0.00 0.00

222 07336500

U 302 55.0 11.3 4.00 1.05 151 26.3 1.05 0.04 0.02 244 36.9 3.71 0.04 0.02

223 07336750

U 0.51 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.22 0.00 0.00 0.00 0.00

224 07336800

U 0.37 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.88 0.00 0.00 0.00 0.00

225 07336820

R 11,600 5,170 3,070 2,290 1800 7,750 4,230 2,580 1,960 1,520 8,230 3,430 1,770 1,260 846

226 07337500

U 177 27.0 4.44 1.84 1.01 99.2 15.2 1.07 0.10 0.03 190 23.0 1.09 0.04 0.02

R 216 48.4 15.0 10.2 7.44 107 26.3 12.7 8.57 5.08 247 32.8 17.1 12.6 8.97
Tables 111

Table 6. July, August, and September flow duration statistics for selected streamflow-gaging stations and periods of record. —Continued[Map No.: See figure 1; USGS, U.S. Geological Survey; ID, identifier; Type of record, period of record type where flow statistics were computed, years are listed for each station and type of record in table 1; U, unregulated; UI, unregulated irrigated; R, regulated; RI, regulated irrigated; UUrb, unregulated urban; JULDxx, first three letters indicate the month where daily mean discharge is equaled or exceeded 

xx percent of the time, in cubic feet per second]

Map 

no.

USGS 

station ID

Type 

of 

record

Monthly flow-duration statistics

JULD20 JULD50 JULD80 JULD90 JULD95 AUGD20 AUGD50 AUGD80 AUGD90 AUGD95 SEPD20 SEPD50 SEPD80 SEPD90 SEPD95

227 07337900 U 71.0 15.3 3.99 1.77 0.73 33.2 8.19 1.86 0.27 0.00 90.2 8.52 1.53 0.17 0.00

228 07338500 U 302 75.8 23.7 13.7 8.74 152 39.6 10.5 4.74 1.18 282 47.5 8.72 3.39 1.97

R 500 143 49.9 31.9 23.6 257 69.5 37.4 24.3 17.2 522 75.1 36.6 27.5 21.1

229 07338750 U 177 33.9 9.05 4.73 3.02 31.5 10.6 3.88 2.31 1.79 92.1 14.5 3.27 1.85 1.24

230 07339000 U 281 59.0 12.8 4.86 1.02 166 30.8 3.71 0.05 0.02 198 39.3 4.73 0.09 0.03

R 1,580 617 280 192 159 1,250 568 289 198 169 794 404 215 173 152

231 07339500 U 51.2 9.80 2.52 1.73 1.34 25.5 6.81 1.77 0.64 0.34 31.0 6.10 1.61 0.33 0.10

232 07340300 U 59.1 24.7 15.3 12.4 10.5 29.7 17.6 12.3 10.4 9.37 36.7 18.2 12.1 9.95 8.35

233 07340500 U 142 40.3 16.1 10.9 8.08 75.5 26.0 12.3 6.66 4.07 91.9 23.4 10.5 5.92 3.44

234 07341000 U 34.4 6.12 0.72 0.26 0.18 13.4 3.20 0.45 0.10 0.00 28.2 3.38 0.31 0.07 0.00

235 07341200 U 53.0 13.6 2.71 1.11 0.74 18.8 5.47 1.67 0.82 0.67 39.0 5.22 1.60 1.13 0.89
112 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis. 

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin characteristics 

follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow 

path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map no.

(fig. 1)

USGS

station ID

Regression 

region1

Contributing 

drainage area, 

in square miles

(CONTDA)

10-85

channel slope, 

in percent 

(CSL10_85fm)

Drainage

basin hillslope, 

in percent 

(BSLDEM10M)

Soil

permeability 

in inches per 

hour

(SOILPERM)

Percent forest 

canopy

(CANOPY_PCT)

Outlet elevation, 

in feet above 

NAVD 1988

(OUTLETELEV)

3 07148350 1 827 9.40 5.97 2.63 0.64 1,410

4 07148400 1 982 8.43 6.07 2.63 0.71 1,300

5 07149000 1 885 7.96 5.95 2.42 1.68 1,290

6 07149500 1 2,360 7.99 5.32 2.52 1.18 1,160

9 07151500 1 813 7.67 2.21 2.60 2.50 1,110

10 07152000 1 1,870 6.58 2.13 1.66 2.39 964

12 07153000 2 538 3.39 3.68 0.78 6.12 821

24 07158400 1 181 8.45 4.52 1.66 5.50 1,100

27 07159750 1 320 4.77 3.06 0.65 7.89 950

30 07160500 1 412 5.67 2.08 1.09 2.07 923

41 07170700 2 36.8 8.80 3.35 0.51 7.72 801

44 07172000 2 429 7.02 6.43 0.47 4.25 767

45 07173000 2 711 5.45 6.70 0.61 8.09 710

46 07174200 2 503 4.92 5.65 0.70 10.6 692

48 07174600 2 138 9.67 7.35 1.07 18.8 697

54 07176500 2 369 6.05 6.96 0.99 15.8 652

55 07176800 2 31.4 15.2 7.95 1.10 20.7 682

56 07177000 2 340 4.50 7.27 1.05 17.3 714

57 07177500 2 907 4.09 6.95 0.99 17.6 583

64 07184000 2 196 3.43 1.79 0.46 5.97 821

67 07185500 2 4.02 27.0 3.35 1.43 8.25 1,190

68 07185700 2 306 6.04 3.97 1.28 12.9 1,020

69 07185765 2 448 5.18 3.78 1.28 15.6 930

70 07186000 2 1,160 2.51 2.64 1.09 10.8 839

72 07187000 3 427 5.83 5.47 1.31 24.8 890

74 07188000 2 2,520 2.07 3.22 1.11 15.4 746

76 07189000 3 851 6.81 14.2 1.59 45.1 760

78 07189540 3 8.00 28.5 2.85 1.00 8.41 930

79 07189542 3 48.6 23.2 6.12 1.34 20.8 800

81 07191000 2 450 4.45 3.02 0.76 7.99 632

82 07191220 3 132 14.2 9.61 1.53 35.6 878

84 07192000 2 227 3.71 3.91 1.00 15.0 589

88 07194800 3 167 13.4 8.18 1.40 31.7 1,030

89 07195000 3 130 15.8 4.22 1.28 12.4 1,060

90 07195430 3 568 7.08 7.58 1.39 26.1 933
Tables 113

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop 

regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin characteristics follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, 

accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and 

along the longest flow path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map

no.

Mean drainagebasin elevation, 

in feet above 

NAVD 1988 

(ELEV)

Mean annual 

precipitation2

in inches 

(PRECIPOUT)

Mean winterspring precipitation2

, in inches 

(PREG_11_05)

Mean summerautumn precipitation2

, in inches 

(PREG_06_10)

Mean April

precipitation2

in inches 

(APRAVPRE)

Mean June 

precipitation2

in inches 

(JUNAVPRE)

Mean 

December 

precipitation2

in inches 

(DECAVPRE)

3 1,870 27.6 13.4 14.2 2.48 3.62 1.00

4 1,820 28.9 14.6 14.3 2.63 3.62 1.07

5 1,820 29.5 14.5 15.0 2.64 3.95 1.07

6 1,730 30.5 15.3 15.1 2.71 3.75 1.22

9 1,520 32.5 16.3 16.2 2.99 4.25 1.29

10 1,360 35.8 17.9 17.9 3.64 4.40 1.49

12 1,040 39.5 20.7 18.7 3.73 4.12 1.83

24 1,300 31.7 16.3 15.4 2.87 4.04 1.38

27 1,130 35.6 19.2 16.4 3.21 4.44 1.92

30 1,120 34.0 17.7 16.3 3.27 4.42 1.59

41 945 43.7 22.1 21.7 3.89 5.33 2.16

44 1,130 39.9 20.3 19.6 3.53 4.65 1.88

45 1,050 37.4 19.5 17.9 3.58 4.07 1.75

46 906 39.2 20.8 18.5 3.74 4.40 1.97

48 952 40.1 21.1 19.0 3.87 4.60 2.03

54 922 41.2 21.9 19.4 3.91 4.66 2.13

55 885 41.3 21.9 19.4 3.91 4.67 2.12

56 878 40.9 21.7 19.2 3.89 4.58 2.12

57 870 41.3 22.2 19.1 3.83 4.57 2.29

64 928 43.7 22.4 21.3 4.10 4.96 2.21

67 1,280 45.0 24.0 21.0 4.17 5.18 2.95

68 1,280 45.1 24.0 21.1 4.25 5.26 2.86

69 1,230 45.0 23.6 21.4 4.35 5.36 2.73

70 1,080 45.2 23.6 21.6 4.19 5.19 2.61

72 1,230 45.4 24.2 21.2 4.29 5.22 2.79

74 1,070 45.6 24.7 20.9 4.19 4.67 2.64

76 1,200 44.7 24.6 20.1 4.17 4.88 2.99

78 1,020 45.6 25.3 20.3 4.23 4.92 3.11

79 1,050 45.5 25.2 20.3 4.20 4.89 3.07

81 781 44.6 24.3 20.3 4.03 4.63 2.79

82 1,210 47.1 26.4 20.7 4.31 5.02 3.34

84 729 43.4 23.5 20.0 4.06 4.83 2.45

88 1,300 47.2 27.0 20.2 4.38 5.06 3.42

89 1,280 46.9 26.7 20.1 4.31 5.09 3.41

90 1,250 47.7 26.9 20.8 4.39 5.04 3.48
114 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin characteristics 

follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow 

path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map no. 

(fig. 1)

USGS 

station ID

Regression 

region1

Contributing 

drainage area, 

in square miles

(CONTDA)

10-85 

channel slope, 

in percent 

(CSL10_85fm)

Drainagebasin hillslope, 

in percent 

(BSLDEM10M)

Soil 

permeability in 

inches per

hour 

(SOILPERM)

Percent forest 

canopy 

(CANOPY_PCT)

Outlet elevation, 

in feet above 

NAVD 1988 

(OUTLETELEV)

91 07195500 3 630 6.59 7.61 1.39 26.4 901

92 07195800 3 14.7 38.2 6.49 1.58 26.3 1,180

94 07195865 3 19.1 22.4 3.32 1.27 11.8 980

95 07196000 3 116 15.3 6.79 1.42 25.2 861

96 07196500 3 950 4.54 9.59 1.51 32.2 680

97 07196900 3 41.1 39.0 11.2 1.52 39.7 1,000

98 07196973 3 24.9 32.8 10.5 1.49 32.3 814

99 07197000 3 312 10.3 12.4 1.62 42.3 720

100 07197360 3 90.2 21.9 10.5 1.54 38.8 640

101 07198000 3 1,610 3.83 10.4 1.55 36.9 480

105 07229300 2 202 6.61 4.92 1.48 12.8 1,030

107 07230500 3 463 5.54 6.04 1.44 34.1 902

108 07231000 3 888 3.30 6.25 1.37 34.4 742

122 07237500 1 8,380 9.21 2.91 2.59 0.33 1,840

123 07238000 1 9,060 8.58 2.96 2.80 0.74 1,680

135 07243000 3 68.4 13.8 4.46 1.46 19.5 840

136 07243500 3 2,000 2.41 5.35 1.46 26.5 645

137 07244000 3 2,300 1.98 5.23 1.43 27.0 587

139 07245500 3 181 13.2 12.0 1.59 48.5 475

140 07247000 3 204 8.89 11.0 1.18 56.0 570

141 07247015 3 268 5.77 11.7 1.19 58.4 520

142 07247250 3 94.3 41.2 19.2 1.86 81.0 687

143 07247500 3 120 14.7 10.8 1.37 48.6 552

144 07248500 3 994 3.47 12.4 1.40 61.9 460

145 07249400 3 147 16.2 8.23 1.08 39.5 460

147 07249500 3 34.8 34.0 19.2 1.52 70.0 860

148 07249985 3 434 15.7 16.0 1.59 66.6 429

149 07250000 3 438 15.1 16.0 1.59 66.5 402

155 07299670 1 320 7.10 1.76 0.83 0.73 1,440

162 07301500 1 2,100 9.57 3.91 3.44 1.40 1,680

164 07303400 1 438 15.8 5.79 2.17 1.17 1,710

165 07303500 1 846 10.9 5.67 2.03 1.18 1,530

166 07304500 1 549 6.33 2.40 1.39 1.38 1,430

173 07311500 1 604 5.92 1.99 0.26 0.64 932

174 07313000 2 157 9.11 3.53 1.49 7.85 1,010
Tables 115

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop 

regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin 

characteristics follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage 

and along the longest flow path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map

no.

Mean drainagebasin elevation, 

in feet above 

NAVD 1988 

(ELEV)

Mean annual 

precipitation2

in inches 

(PRECIPOUT)

Mean winterspring precipitation2

, in inches 

(PREG_11_05)

Mean summerautumn precipitation2

, in inches 

(PREG_06_10)

Mean April 

precipitation2 

in inches 

(APRAVPRE)

Mean June 

precipitation2

in inches 

(JUNAVPRE)

Mean

December

precipitation2

in inches 

(DECAVPRE)

91 1,240 47.7 26.8 20.9 4.38 5.04 3.49

92 1,330 47.7 27.1 20.6 4.39 5.13 3.50

94 1,140 47.8 26.8 21.0 4.38 5.07 3.48

95 1,160 48.1 26.8 21.3 4.34 5.19 3.48

96 1,180 47.6 26.3 21.3 4.07 5.33 3.22

97 1,340 49.5 28.6 20.8 4.61 5.17 3.53

98 1,070 48.7 28.1 20.6 4.56 5.11 3.51

99 1,140 47.8 26.8 21.0 4.25 5.23 3.29

100 998 47.9 27.3 20.6 4.40 5.19 3.29

101 1,110 46.1 26.1 20.0 4.20 4.84 3.10

105 1,210 40.4 22.0 18.4 3.78 4.70 2.39

107 1,110 38.0 20.9 17.1 3.66 4.61 2.13

108 1,030 41.7 23.2 18.5 4.04 4.74 2.50

122 3,190 26.1 13.1 13.0 2.31 3.36 1.01

123 3,100 28.3 14.5 13.8 2.57 3.54 1.09

135 960 38.5 20.7 17.8 3.49 4.35 1.96

136 911 42.6 23.4 19.2 3.98 4.53 2.50

137 889 43.8 23.9 19.9 4.02 4.47 2.63

139 955 47.4 27.5 19.8 4.36 4.68 3.11

140 870 49.5 30.0 19.4 4.59 4.79 4.29

141 860 50.0 29.8 20.1 4.60 4.83 4.03

142 1,300 51.9 31.1 20.8 4.73 4.89 4.28

143 884 49.3 29.1 20.2 4.73 4.89 3.64

144 858 48.3 28.5 19.8 4.45 4.93 3.73

145 753 47.3 28.6 18.7 4.29 4.47 3.76

147 1,390 51.0 30.0 21.1 4.63 4.97 3.58

148 1,120 47.2 28.2 19.1 4.24 4.49 3.51

149 1,120 47.2 28.1 19.1 4.24 4.51 3.52

155 1,640 26.8 12.5 14.3 2.16 3.84 1.15

162 2,490 28.0 14.0 14.0 2.59 3.78 1.04

164 2,240 26.1 12.5 13.6 2.35 3.84 1.02

165 2,020 28.4 13.7 14.7 2.47 4.07 1.10

166 1,750 29.3 14.4 14.9 2.51 4.03 1.27

173 1,150 31.9 16.5 15.4 2.85 3.79 1.65

174 1,210 34.4 18.0 16.3 3.08 4.15 1.81
116 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin characteristics 

follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow 

path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map no. 

(fig. 1)

USGS 

station ID

Regression 

region1

Contributing 

drainage area, 

in square miles 

(CONTDA)

10-85 

channel slope, 

in percent 

(CSL10_85fm)

Drainage

basin hillslope, 

in percent 

(BSLDEM10M)

Soil

permeability 

in inches per 

hour

(SOILPERM)

Percent forest 

canopy 

(CANOPY_PCT)

Outlet elevation, 

in feet above 

NAVD 1988 

(OUTLETELEV)

177 07315700 2 574 3.89 3.19 0.92 9.54 747

180 07319500 1 45.2 37.0 7.23 1.83 1.15 1,870

181 07323000 1 86.1 28.7 7.88 1.54 1.23 1,800

182 07324200 1 1,350 8.12 5.90 2.28 0.72 1,660

184 07325000 1 1,950 6.79 5.83 1.93 0.90 1,480

185 07325500 1 3,100 4.94 5.13 1.54 1.10 1,250

186 07325800 1 132 14.6 4.41 1.58 1.39 1,380

187 07326000 1 311 7.23 3.81 2.19 2.26 1,270

189 07327000 1 206 12.8 8.26 2.95 15.5 1,200

190 073274406 1 3.65 37.7 3.20 0.89 0.28 1,340

191 07327442 1 13.3 39.2 3.83 0.91 1.20 1,270

192 07327447 1 62.3 16.4 4.58 1.15 6.94 1,200

193 07327490 1 208 8.52 5.26 1.66 10.6 1,080

194 07327550 1 232 6.73 5.17 1.62 10.1 1,050

195 07328000 1 4,670 3.73 5.14 1.69 3.16 1,040

196 07328070 1 33.1 20.5 5.04 1.50 12.5 1,050

199 07328500 2 5,290 3.24 5.06 1.66 4.02 866

200 07329000 2 140 9.97 4.90 1.54 15.8 1,000

201 07329500 2 202 8.78 5.11 1.37 15.8 922

203 07329852 2 44.1 14.0 5.24 0.54 18.3 912

204 07329900 2 137 13.7 6.08 0.47 23.3 757

205 07330500 2 296 5.81 5.29 1.00 15.0 724

206 07331000 2 7,160 2.90 5.10 1.50 7.31 654

208 07332400 2 203 10.3 3.22 0.76 16.5 668

209 07332500 2 477 6.98 3.51 0.82 17.2 518

211 07333500 3 32.6 25.4 11.6 1.52 47.5 560

212 07333800 3 88.8 6.10 7.89 1.33 40.1 635

213 07334000 3 1,090 3.18 6.52 1.49 36.8 451

214 07335000 3 713 3.37 4.88 0.96 24.7 492

218 07335700 3 39.6 54.9 22.9 1.62 83.5 895

220 07336000 3 68.3 12.2 8.19 1.25 41.4 480

221 07336200 3 1,130 3.71 12.7 1.44 56.3 436

222 07336500 3 1,420 3.35 11.9 1.48 54.5 391

226 07337500 3 648 9.74 12.8 1.66 59.6 364

227 07337900 3 320 13.5 12.8 1.61 64.5 387
Tables 117

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop 

regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin 

characteristics follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, 

accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along 

the longest flow path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map

no.

Mean drainagebasin elevation, 

in feet above 

NAVD 1988 

(ELEV)

Mean annual 

precipitation2

in inches 

(PRECIPOUT)

Mean winterspring precipitation2

, in inches 

(PREG_11_05)

Mean summerautumn precipitation2

, in inches 

(PREG_06_10)

Mean April 

precipitation2

 in inches 

(APRAVPRE)

Mean June 

precipitation2

in inches 

(JUNAVPRE)

Mean December precipitation2

 in inches 

(DECAVPRE)

177 937 33.7 18.0 15.7 2.77 3.67 1.94

180 2,160 26.9 13.3 13.6 2.39 3.80 1.00

181 2,100 27.0 13.4 13.6 2.39 3.80 1.02

182 2,260 27.9 14.0 13.9 2.44 3.78 1.09

184 2,110 30.9 15.4 15.6 2.51 4.06 1.34

185 1,900 31.3 16.2 15.1 2.75 4.24 1.44

186 1,590 31.3 16.0 15.3 2.82 4.24 1.42

187 1,530 31.9 16.5 15.4 2.83 4.21 1.50

189 1,460 32.7 16.9 15.7 2.91 4.16 1.62

190 1,430 33.6 17.4 16.1 3.06 4.18 1.71

191 1,410 33.7 17.5 16.1 3.07 4.18 1.72

192 1,370 34.4 18.1 16.3 3.16 4.17 1.81

193 1,300 35.0 18.6 16.4 3.33 4.12 1.90

194 1,290 35.1 18.7 16.4 3.37 4.10 1.92

195 1,710 35.3 18.8 16.4 3.38 4.10 1.93

196 1,200 35.5 19.1 16.5 3.40 4.11 1.96

199 1,640 38.6 21.3 17.3 3.61 4.62 2.21

200 1,240 37.3 20.4 16.9 3.56 4.18 2.14

201 1,180 38.1 20.7 17.4 3.62 4.49 2.16

203 1,110 41.5 22.7 18.7 3.68 4.48 2.50

204 1,050 40.5 22.2 18.3 3.62 4.50 2.45

205 979 38.9 21.2 17.7 3.35 4.35 2.39

206 1,480 40.1 22.0 18.2 3.52 4.52 2.51

208 1,070 43.5 24.2 19.3 3.91 4.94 2.91

209 852 44.7 24.8 19.9 3.75 5.14 3.03

211 810 44.3 25.4 18.9 4.26 4.67 3.05

212 848 47.0 27.5 19.5 4.53 4.74 3.39

213 725 46.1 27.3 18.8 4.50 4.52 3.40

214 731 44.6 25.4 19.2 4.10 4.80 3.05

218 1,530 55.5 33.3 22.1 4.96 4.91 4.84

220 697 47.1 27.6 19.4 4.48 4.69 3.55

221 906 46.8 27.1 19.7 4.33 4.69 3.68

222 863 47.9 28.0 19.9 4.27 4.60 3.84

226 923 51.5 30.7 20.8 4.29 4.38 4.58

227 911 52.5 31.3 21.2 4.47 4.43 4.78
118 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin characteristics 

follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow 

path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map no.

(fig. 1)

USGS 

station ID

Regression 

region1

Contributing 

drainage area, 

in square miles 

(CONTDA)

10-85 

channel slope, 

in percent 

(CSL10_85fm)

Drainage

basin hillslope, 

in percent 

(BSLDEM10M)

Soil

permeability 

in inches per 

hour

(SOILPERM)

Percent forest 

canopy 

(CANOPY_PCT)

Outlet elevation, 

in feet above 

NAVD 1988 

(OUTLETELEV)

228 07338500 3 1,230 5.67 11.2 1.61 57.7 313

229 07338750 3 322 15.1 13.6 1.99 62.3 670

230 07339000 3 800 6.82 15.5 1.78 65.6 341

231 07339500 3 183 17.5 12.3 1.61 60.5 339

232 07340300 3 89.1 28.5 28.1 1.70 81.7 765

233 07340500 3 361 15.5 16.8 1.66 68.8 343

234 07341000 3 120 20.9 10.3 1.65 65.0 357

235 07341200 3 253 14.1 8.09 1.38 64.7 305

1

Region 2 includes streamflow gaging stations in regions 2a and 2b (figure 7).

2

Mean annual, seasonal, and monthly precipitation was computed from the period 1971–2000, and reflects the mean precipitation at the gage
Tables 119

Table 8. Selected drainage-basin characteristics for streamflow-gaging stations used in regression analysis.—Continued

[Map no.: see figure 1; USGS, U.S. Geological Survey; ID, identifier; Regression region, regions with similar basin characteristics used to develop 

regression equations to estimate flow-duration and annual mean-flow statistics at ungaged stream locations, see figure 7; abbreviations for basin 

characteristics follow naming conventions used by U.S. Geological Survey StreamStats Webpage (http://water.usgs.gov/osw/streamstats/bcdefinitions1, accessed September 2009); 10-85 channel slope, channel slope between points 10 and 85 percent of the stream length starting from the gage 

and along the longest flow path, in feet per mile; NAVD 1988, North American Vertical Datum of 1988]

Map

no.

Mean drainagebasin elevation, 

in feet above 

NAVD 1988 

(ELEV)

Mean annual 

precipitation2

in inches

(PRECIPOUT)

Mean winterspring precipitation2

, in inches 

(PREG_11_05)

Mean summerautumn precipitation2

, in inches 

(PREG_06_10)

Mean April 

precipitation2

in inches 

(APRAVPRE)

Mean June 

precipitation2

in inches 

(JUNAVPRE)

Mean

December 

precipitation2

in inches 

(DECAVPRE)

228 828 51.5 31.5 20.0 4.35 4.46 4.70

229 1,150 55.6 33.7 21.9 4.83 4.55 4.99

230 1,040 53.1 32.2 20.9 4.48 4.59 4.85

231 848 54.9 34.1 20.8 4.79 4.67 5.24

232 1,320 58.0 35.2 22.8 5.15 5.07 5.23

233 925 55.2 34.2 21.0 4.79 4.78 5.25

234 789 56.2 34.8 21.3 4.88 5.02 5.32

235 625 54.6 33.8 20.9 4.77 4.88 5.16
120 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 9. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 32 streamflow gaging stations in Region 1. —Continued

[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of 

the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx percent of 

the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, 

summer-autumn precipitation defined as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; JUNAVPRE, mean June precipitation at the gage, in inches; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; BSLDEM10M, mean drain-basin slope, in feet per foot; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; 

SOILPERM, mean drainage-basin soil permeability in inches per year; CANOPY_PCT, percentage of drainage-basin that is forested; APRAVPRE, mean April precipitation at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches]

Regression equation1 Method Adjusted R2 (%)

Standard Error 

of Estimate in 

log 10 units of 

ft3/s

Standard Error 

of Estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

Annual Mean Flow

AVE_DV = 65.7(CONTDA/424)0.83(PREG_06_10/15.2)7.50 OLS 95.0 0.144 33.8 66.9

Flow Duration Statistics

D20 = 59.5(CONTDA/424)0.85(ELEV/1721)-0.8(PREG_06_10/15.2)4.81 OLS 92.1 0.178 42.4 70.8

D50 = 23.0(CONTDA/424)0.83(ELEV/1721)-1.15(PREG_06_10/15.2)4.53 OLS 85.4 0.237 58.7 24.1D80 = 7.15(CONTDA/424)0.81(ELEV/1721)-4.49(PREG_06_10/15.2)2.78 OLS 50.8 0.564 202 5.91D90 = [2.61(CONTDA/424)0.75(ELEV/1721)-5.28(PREG_06_10/15.2)8.16] - 0.1 Tobit 50.2 0.677 282 2.55

D95 = [1.54(CONTDA/424)0.63(ELEV/1721)-4.97(PREG_06_10/15.2)8.45] - 0.1 Tobit 37.9 0.754 351 0.88D20SUM = 56.3(CONTDA/424)0.85(CSL10_85fm/8.56)-0.08(PREG_06_10/15.2)7.07(JUNAVPRE/4.06)-0.85 OLS 91.3 0.192 46.2 60.7

D50SUM = 16.9(CONTDA/424)0.65(CSL10_85fm/8.56)-0.55(PREG_06_10/15.2)5.43(JUNAVPRE/4.06)2.32 OLS 81.7 0.285 73.6 13.3

D80SUM = [5.55(CONTDA/424)0.14(CSL10_85fm/8.56)-1.36(PREG_06_10/15.2)0.56(JUNAVPRE/4.06)16.7] - 0.08 OLS 54.6 0.582 214 3.02

D90SUM = [2.23(CONTDA/424)0.04(CSL10_85fm/8.56)-1.69(PREG_06_10/15.2)-0.01(JUNAVPRE/4.06)21.2] - 0.08 Tobit 53.2 0.664 272 1.14

D95SUM = [1.06(CONTDA/424)0.05(CSL10_85fm/8.56)-1.64(PREG_06_10/15.2)-0.78(JUNAVPRE/4.06)25.7] - 0.08 Tobit 52.6 0.673 280 0.16D20WSP = 59.4(CONTDA/424)0.74(OUTLETELEV/1294)-2.41(BSLDEM10M/4.55)0.06(PREG_11_05/15.7)0.49 OLS 91.0 0.183 43.2 70.6

D50WSP = 25.3(CONTDA/424)0.71(OUTLETELEV/1294)-2.55(BSLDEM10M/4.55)0.13(PREG_11_05/15.7)0.52 OLS 84.6 0.240 59.5 24.7D80WSP = 10.6(CONTDA/424)0.59(OUTLETELEV/1294)-5.75(BSLDEM10M/4.55)0.54(PREG_11_05/15.7)-2.55 OLS 72.4 0.341 92.8 9.53D90WSP = [5.46(CONTDA/424)0.31(OUTLETELEV/1294)-10.0(BSLDEM10M/4.55)0.95(PREG_11_05/15.7)-6.71] - 0.2 OLS 59.2 0.477 153 5.99

D95WSP = [3.39(CONTDA/424)0.21(OUTLETELEV/1294)-9.80(BSLDEM10M/4.55)0.56(PREG_11_05/15.7)-5.1] - 0.5 Tobit 48.0 0.552 194 3.72

OCTD20 = 42.2(CONTDA/424)0.73(CSL10_85fm/8.56)-0.14(SOILPERM/2.17)-0.07(PREG_06_10/15.2)6.32 OLS 89.2 0.209 50.0 40.2

OCTD50 = 15.5(CONTDA/424)0.42(CSL10_85fm/8.56)-0.92(SOILPERM/2.17)0.03(PREG_06_10/15.2)6.73 OLS 79.8 0.325 86.6 10.1

OCTD80 = [4.64(CONTDA/424)0.00(CSL10_85fm/8.56)-1.32(SOILPERM/2.17)-0.13(PREG_06_10/15.2)13.4] - 0.2 Tobit 50.4 0.536 185 3.27
Tables 121

Table 9. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 32 streamflow gaging stations in Region 1. —Continued[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of 

the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx percent of 

the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, 

summer-autumn precipitation defined as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; JUNAVPRE, mean June precipitation at the gage, in inches; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; BSLDEM10M, mean drain-basin slope, in feet per foot; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; 

SOILPERM, mean drainage-basin soil permeability in inches per year; CANOPY_PCT, percentage of drainage-basin that is forested; APRAVPRE, mean April precipitation at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches]

Regression equation1 Method Adjusted R2 (%)

Standard Error 

of Estimate in 

log 10 units of 

ft3/s

Standard Error 

of Estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

OCTD90 = [2.23(CONTDA/424)0.00(CSL10_85fm/8.56)-1.54(SOILPERM/2.17)-0.55(PREG_06_10/15.2)14.9] - 0.2 Tobit 45.7 0.572 206 1.48

OCTD95 = [0.61(CONTDA/424)0.00(CSL10_85fm/8.56)-1.54(SOILPERM/2.17)-1.81(PREG_06_10/15.2)17.8] - 0.08 Tobit 42.3 0.717 333 0.26NOVD20 = 52.5(CONTDA/424)0.60(CSL10_85fm/8.56)-0.39(BSLDEM10M/4.55)0.14(PREG_06_10/15.2)5.57 OLS 85.0 0.221 53.6 42.2

NOVD50 = 22.9(CONTDA/424)0.55(CSL10_85fm/8.56)-0.42(BSLDEM10M/4.55)0.28(PREG_06_10/15.2)7.63 OLS 74.5 0.297 77.3 16.6

NOVD80 = [12.5(CONTDA/424)0.00(CSL10_85fm/8.56)-1.51(BSLDEM10M/4.55)0.94(PREG_06_10/15.2)12.0] - 0.2 OLS 51.4 0.534 190 6.3

NOVD90 = [5.74(CONTDA/424)0.00(CSL10_85fm/8.56)-1.75(BSLDEM10M/4.55)0.63(PREG_06_10/15.2)18.0] - 0.1 Tobit 52.7 0.726 338 3.57NOVD95 = [1.34(CONTDA/424)0.00(CSL10_85fm/8.56)-1.62(BSLDEM10M/4.55)0.73(PREG_06_10/15.2)29.6] - 0.01 Tobit 46.6 0.97 622 1.9

DECD20 = 47.3(CONTDA/424)0.69(OUTLETELEV/1294)-2.34 OLS 90.4 0.176 41.7 41.6

DECD50 = 24.6(CONTDA/424)0.66(OUTLETELEV/1294)-2.80 OLS 81.4 0.255 63.9 19.9

DECD80 = 11.3(CONTDA/424)0.56(OUTLETELEV/1294)-4.60 OLS 65.5 0.400 117 7.7

DECD90 = [7.94(CONTDA/424)0.38(OUTLETELEV/1294)-5.26] - 0.4 OLS 53.7 0.471 150 4.43

DECD95 = [6.39(CONTDA/424)0.35(OUTLETELEV/1294)-6.29] - 0.4 Tobit 45.4 0.571 206 3.26

JAND20 = 47.5(CONTDA/424)0.84(CANOPY_PCT/1.31)-0.03(BSLDEM10M/4.55)0.12(ELEV/1721)-2.18 OLS 88.7 0.197 46.9 45.6

JAND50 = 24.8(CONTDA/424)0.86(CANOPY_PCT/1.31)-0.06(BSLDEM10M/4.55)0.19(ELEV/1721)-2.53 OLS 80.1 0.272 69.1 22

JAND80 = 12.8(CONTDA/424)0.90(CANOPY_PCT/1.31)-0.23(BSLDEM10M/4.55)0.81(ELEV/1721)-4.99 OLS 66.1 0.382 109 9.22

JAND90 = [9.91(CONTDA/424)0.76(CANOPY_PCT/1.31)-0.54(BSLDEM10M/4.55)1.31(ELEV/1721)-7.14] - 0.5 Tobit 55.3 0.455 142 5.24

JAND95 = [7.74(CONTDA/424)0.74(CANOPY_PCT/1.31)-0.57(BSLDEM10M/4.55)1.21(ELEV/1721)-7.91] - 0.5 Tobit 45.9 0.530 182 3.91FEBD20 = 57.7(CONTDA/424)0.70(OUTLETELEV/1294)-2.41(BSLDEM10M/4.55)0.04 OLS 88.3 0.200 47.6 48.3

FEBD50 = 28.8(CONTDA/424)0.72(OUTLETELEV/1294)-2.65(BSLDEM10M/4.55)0.12 OLS 84.7 0.242 60.2 21FEBD80 = 15.2(CONTDA/424)0.71(OUTLETELEV/1294)-3.27(BSLDEM10M/4.55)0.20 OLS 79.3 0.294 76.5 12.8FEBD90 = 10.0(CONTDA/424)0.64(OUTLETELEV/1294)-5.48(BSLDEM10M/4.55)0.47 OLS 61.5 0.447 138 6.52
122 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 9. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 32 streamflow gaging stations in Region 1. —Continued

[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of 

the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx percent of 

the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, 

summer-autumn precipitation defined as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; JUNAVPRE, mean June precipitation at the gage, in inches; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; BSLDEM10M, mean drain-basin slope, in feet per foot; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; 

SOILPERM, mean drainage-basin soil permeability in inches per year; CANOPY_PCT, percentage of drainage-basin that is forested; APRAVPRE, mean April precipitation at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches]

Regression equation1 Method Adjusted R2 (%)

Standard Error 

of Estimate in 

log 10 units of 

ft3/s

Standard Error 

of Estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

FEBD95 = [7.99(CONTDA/424)0.45(OUTLETELEV/1294)-6.01(BSLDEM10M/4.55)0.53] - 0.2 OLS 52.7 0.527 180 4.06

MARD20 = 73.1(CONTDA/424)0.74(OUTLETELEV/1294)-2.79 OLS 87.4 0.227 55.6 64.2

MARD50 = 32.7(CONTDA/424)0.72(OUTLETELEV/1294)-2.64 OLS 83.7 0.254 63.5 24.1MARD80 = 16.6(CONTDA/424)0.71(OUTLETELEV/1294)-3.23 OLS 76.1 0.329 88.8 13.7

MARD90 = 11.0(CONTDA/424)0.61(OUTLETELEV/1294)-4.82 OLS 62.7 0.462 145 6.29

MARD95 = [9.83(CONTDA/424)0.44(OUTLETELEV/1294)-5.33] - 0.3 OLS 51.1 0.533 183 4.86

APRD20 = 83.4(CONTDA/424)0.80(OUTLETELEV/1294)-2.60(APRAVPRE/2.73)1.03 OLS 90.4 0.211 51.3 91.5

APRD50 = 31.7(CONTDA/424)0.75(OUTLETELEV/1294)-1.71(APRAVPRE/2.73)2.07 OLS 87.6 0.224 54.3 30.4APRD80 = 15.2(CONTDA/424)0.73(OUTLETELEV/1294)-2.02(APRAVPRE/2.73)2.28 OLS 79.6 0.298 78.0 12.7APRD90 = 10.1(CONTDA/424)0.65(OUTLETELEV/1294)-4.54(APRAVPRE/2.73)0.56 OLS 65.8 0.437 133 6.29APRD95 = 7.38(CONTDA/424)0.56(OUTLETELEV/1294)-7.06(APRAVPRE/2.73)-1.14 OLS 56.6 0.574 208 4.28

MAYD20 = 128(CONTDA/424)0.91(OUTLETELEV/1294)-1.42(PREG_06_10/15.2)3.93 OLS 93.3 0.187 44.7 145

MAYD50 = 41.0(CONTDA/424)0.82(OUTLETELEV/1294)-1.42(PREG_06_10/15.2)4.5 OLS 88.9 0.223 54.3 40MAYD80 = 15.2(CONTDA/424)0.76(OUTLETELEV/1294)-2.49(PREG_06_10/15.2)3.2 OLS 81.8 0.287 74.3 12.9MAYD90 = 8.45(CONTDA/424)0.78(OUTLETELEV/1294)-2.98(PREG_06_10/15.2)5.89 OLS 76.9 0.366 102 6.43MAYD95 = [5.71(CONTDA/424)0.63(OUTLETELEV/1294)-5.15(PREG_06_10/15.2)4.31] - 0.1 OLS 58.4 0.567 204 3.71

JUND20 = 134(CONTDA/424)0.94(OUTLETELEV/1294)-0.52 (PRECIPOUT/31.1)4.32 OLS 94.1 0.177 41.7 162

JUND50 = 41.3(CONTDA/424)0.88(OUTLETELEV/1294)-0.87(PRECIPOUT/31.1)3.90 OLS 91.4 0.204 49.1 38.6JUND80 = 12.2(CONTDA/424)0.78(OUTLETELEV/1294)-3.41(PRECIPOUT/31.1)0.81 OLS 81.7 0.302 79.5 10.9JUND90 = [6.47(CONTDA/424)0.64(OUTLETELEV/1294)-4.57(PRECIPOUT/31.1)0.10] - 0.2 Tobit 63.2 0.433 131 4.15

JUND95 = [4.62(CONTDA/424)0.37(OUTLETELEV/1294)-7.49(PRECIPOUT/31.1)-2.84] - 0.4 Tobit 51.6 0.533 183 2.01
Tables 123

Table 9. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 32 streamflow gaging stations in Region 1. —Continued[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of 

the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx percent of 

the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, 

summer-autumn precipitation defined as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; JUNAVPRE, mean June precipitation at the gage, in inches; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; BSLDEM10M, mean drain-basin slope, in feet per foot; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; 

SOILPERM, mean drainage-basin soil permeability in inches per year; CANOPY_PCT, percentage of drainage-basin that is forested; APRAVPRE, mean April precipitation at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches]

Regression equation1 Method Adjusted R2 (%)

Standard Error 

of Estimate in 

log 10 units of 

ft3/s

Standard Error 

of Estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

JULD20 = 52.2(CONTDA/424)1.00(CSL10_85fm/8.56)0.35(BSLDEM10M/4.55)-0.09(PREG_06_10/15.2)7.63 OLS 94.2 0.170 40.0 53.2

JULD50 = 18.2(CONTDA/424)0.79(CSL10_85fm/8.56)-0.21(BSLDEM10M/4.55)0.02(PREG_06_10/15.2)7.64 OLS 91.2 0.191 45.6 14.2

JULD80 = [6.18(CONTDA/424)0.30(CSL10_85fm/8.56)-1.36(BSLDEM10M/4.55)0.77(PREG_06_10/15.2)12.7] - 0.02 OLS 67.8 0.471 150 2.5

JULD90 = [2.10(CONTDA/424)0.00(CSL10_85fm/8.56)-2.02(BSLDEM10M/4.55)0.66(PREG_06_10/15.2)16.1] - 0.1 Tobit 51.3 0.684 289 0.63

JULD95 = [0.73(CONTDA/424)0.00(CSL10_85fm/8.56)-2.64(BSLDEM10M/4.55)0.25(PREG_06_10/15.2)15.2] - 0.1 Tobit 45.9 0.740 338 0.06

AUGD20 = 35.5(CONTDA/424)0.87(CSL10_85fm/8.56)0.07(PREG_06_10/15.2)6.97 OLS 90.8 0.201 48.3 34.6

AUGD50 = 10.6(CONTDA/424)0.62(CSL10_85fm/8.56)-0.54(PREG_06_10/15.2)7.30 OLS 85.2 0.255 63.8 8.65AUGD80 = [2.76(CONTDA/424)0.05(CSL10_85fm/8.56)-2.05(PREG_06_10/15.2)15.1] - 0.03 Tobit 42.1 0.839 442 1.69

AUGD90 = [1.78(CONTDA/424)0.03(CSL10_85fm/8.56)-1.44(PREG_06_10/15.2)13.8] - 0.2 Tobit 40.4 0.646 259 0.42

AUGD95 = [1.05(CONTDA/424)0.03(CSL10_85fm/8.56)-1.79(PREG_06_10/15.2)11.2] - 0.3 Tobit 29.3 0.689 293 0.02

SEPD20 = 33.7(CONTDA/424)0.89(CSL10_85fm/8.56)0.26(SOILPERM/76.7)-0.38(OUTLETELEV/1294)-2.97 OLS 91.1 0.191 45.7 35.6

SEPD50 = 9.78(CONTDA/424)0.60(CSL10_85fm/8.56)-0.41(SOILPERM/76.7)-0.75(OUTLETELEV/1294)-3.06 OLS 65.4 0.418 124 8.59SEPD80 = [2.84(CONTDA/424)0.00(CSL10_85fm/8.56)-1.57(SOILPERM/76.7)-0.75(OUTLETELEV/1294)-4.50] - 0.09 Tobit 38.3 0.775 371 2.11

SEPD90 = [1.35(CONTDA/424)0.10(CSL10_85fm/8.56)-0.83(SOILPERM/76.7)-1.10(OUTLETELEV/1294)-5.02] - 0.2 Tobit 37.2 0.604 229 0.36SEPD95 = [0.77(CONTDA/424)0.00(CSL10_85fm/8.56)-1.00(SOILPERM/76.7)-1.17(OUTLETELEV/1294)-4.17] - 0.2 Tobit 36.9 0.591 219 0.04

1Final units of all computations from regression equations are in cubic feet per second (ft3/s). Definition and naming conventions for statistics follow that of USGS StreamStats (http://water.usgs.gov/osw/

streamstats/StatisticsDefinitions.html, accessed September 10, 2009)
124 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 10. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 30 streamflow gaging stations in Region 2. —Continued

[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent 

of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx 

percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; CSL10_85fm, channel slope between points 10 and 85 percent of the stream 

length starting from the gage and along the longest flow path, in feet per mile; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches] 

Regression Equation1 Method Adjusted R2 (%)

Standard 

error of 

estimate in 

log 10 units 

of ft3/s

Standard error 

of estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

Annual Mean Flow

AVE_DV = 193(CONTDA/323)0.91(PREG_06_10/19.3)3.35 OLS 95.1 0.129 30.3 181

Flow Duration Statistics

D20 = 142(CONTDA/323)1.09(CSL10_85fm/6.04)0.23(OUTLETELEV/783)1.04(PREG_11_05/22.0)5.92 OLS 91.6 0.188 44.7 79.8

D50 = 32.1(CONTDA/323)1.51(CSL10_85fm/6.04)1.00(OUTLETELEV/783)2.76(PREG_11_05/22.0)9.29 OLS 91.2 0.234 57.3 17.6D80 = [7.01(CONTDA/323)2.19(CSL10_85fm/6.04)2.26(OUTLETELEV/783)4.93(PREG_11_05/22.0)14.7] - 0.1 OLS 87.5 0.359 100 3.23D90 = [3.44(CONTDA/323)2.58(CSL10_85fm/6.04)2.89(OUTLETELEV/783)5.90(PREG_11_05/22.0)20.5] - 0.1 Tobit 81.3 0.587 217 1.38

D95 = [2.21(CONTDA/323)2.35(CSL10_85fm/6.04)2.71(OUTLETELEV/783)5.90(PREG_11_05/22.0)21.9] - 0.2 Tobit 81.0 0.550 194 0.45D20SUM = 84.3(CONTDA/323)1.31(CSL10_85fm/6.04)0.42(OUTLETELEV/783)1.81(PREG_11_05/22.0)5.93 OLS 94.5 0.167 39.5 47.6

D50SUM = 17.7(CONTDA/323)1.93(CSL10_85fm/6.04)1.57(OUTLETELEV/783)3.87(PREG_11_05/22.0)10.6 OLS 90.4 0.280 72.1 12.1D80SUM = [5.95(CONTDA/323)2.00(CSL10_85fm/6.04)1.92(OUTLETELEV/783)5.00(PREG_11_05/22.0)15.0] - 0.5 Tobit 82.2 0.432 131 2.52

D90SUM = [3.67(CONTDA/323)2.02(CSL10_85fm/6.04)2.12(OUTLETELEV/783)5.36(PREG_11_05/22.0)18.3] - 0.5 Tobit 80.1 0.487 158 1.61D95SUM = [2.01(CONTDA/323)1.83(CSL10_85fm/6.04)1.86(OUTLETELEV/783)5.27(PREG_11_05/22.0)18.4] - 0.5 Tobit 77.6 0.462 145 0.64D20WSP = 179(CONTDA/323)1.00(CSL10_85fm/6.04)0.13(OUTLETELEV/783)0.65(PREG_11_05/22.0)5.81 OLS 89.0 0.211 50.6 123

D50WSP = 48.0(CONTDA/323)1.31(CSL10_85fm/6.04)0.77(OUTLETELEV/783)2.27(PREG_11_05/22.0)8.97 OLS 88.8 0.236 58.0 25.8D80WSP = 11.6(CONTDA/323)1.95(CSL10_85fm/6.04)1.95(OUTLETELEV/783)4.28(PREG_11_05/22.0)11.9 OLS 85.6 0.346 95.0 7.47D90WSP = [4.97(CONTDA/323)2.48(CSL10_85fm/6.04)2.90(OUTLETELEV/783)5.96(PREG_11_05/22.0)15.7] - 0.03 OLS 79.0 0.524 178 3.30

D95WSP = [2.85(CONTDA/323)2.35(CSL10_85fm/6.04)2.76(OUTLETELEV/783)6.03(PREG_11_05/22.0)20.1] - 0.2 Tobit 88.4 0.476 152 1.62OCTD20 = 67.7(CONTDA/323)1.33(CSL10_85fm/6.04)0.75(OUTLETELEV/783)1.62(PRECIPOUT/41.3)7.18 OLS 93.9 0.162 38.0 46.4

OCTD50 = 14.0(CONTDA/323)2.13(CSL10_85fm/6.04)2.42(OUTLETELEV/783)4.01(PRECIPOUT/41.3)12.2 OLS 84.9 0.350 96.5 9.70OCTD80 = [5.82(CONTDA/323)1.99(CSL10_85fm/6.04)2.36(OUTLETELEV/783)4.17(PRECIPOUT/41.3)15.0] - 0.8 Tobit 78.5 0.450 140 1.51

OCTD90 = [3.07(CONTDA/323)2.21(CSL10_85fm/6.04)2.9(OUTLETELEV/783)4.44(PRECIPOUT/41.3)19.8] - 0.5 Tobit 76.7 0.503 166 0.63

OCTD95 = [0.80(CONTDA/323)2.82(CSL10_85fm/6.04)4.06(OUTLETELEV/783)5.08(PRECIPOUT/41.3)29.0] - 0.1 Tobit 72.6 0.719 319 0.02
Tables 125

Table 10. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 30 streamflow gaging stations in Region 2. —Continued[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent 

of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx 

percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; CSL10_85fm, channel slope between points 10 and 85 percent of the stream 

length starting from the gage and along the longest flow path, in feet per mile; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches] 

Regression Equation1 Method Adjusted R2 (%)

Standard 

error of 

estimate in 

log 10 units 

of ft3/s

Standard error 

of estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

NOVD20 = 106(CONTDA/323)1.06(CSL10_85fm/6.04)0.21(OUTLETELEV/783)1.66(PREG_11_05/22.0)6.85 OLS 86.0 0.243 60.2 61.1

NOVD50 = 20.8(CONTDA/323)1.67(CSL10_85fm/6.04)1.48(OUTLETELEV/783)3.46(PREG_11_05/22.0)9.22 OLS 86.2 0.291 75.0 13.1NOVD80 = [5.10(CONTDA/323)2.45(CSL10_85fm/6.04)2.96(OUTLETELEV/783)5.72(PREG_11_05/22.0)16.9] - 0.08 OLS 79.9 0.517 174 2.53

NOVD90 = [3.92(CONTDA/323)2.14(CSL10_85fm/6.04)2.46(OUTLETELEV/783)5.71(PREG_11_05/22.0)19.1] - 0.3 Tobit 81.7 0.476 152 1.04NOVD95 = [2.45(CONTDA/323)2.05(CSL10_85fm/6.04)2.45(OUTLETELEV/783)5.29(PREG_11_05/22.0)19.8] - 0.4 Tobit 80.4 0.461 145 0.41DECD20 = 109(CONTDA/323)1.09(CSL10_85fm/6.04)0.35(OUTLETELEV/783)1.42(PREG_11_05/22.0)7.09 OLS 83.4 0.267 67.6 54.9

DECD50 = 28.1(CONTDA/323)1.60(CSL10_85fm/6.04)1.28(OUTLETELEV/783)3.41(PREG_11_05/22.0)9.58 OLS 84.8 0.311 82.5 16.4DECD80 = [7.82(CONTDA/323)2.12(CSL10_85fm/6.04)2.37(OUTLETELEV/783)5.04(PREG_11_05/22.0)13.2] - 0.09 OLS 82.0 0.417 124 3.57

DECD90 = [5.34(CONTDA/323)2.03(CSL10_85fm/6.04)2.27(OUTLETELEV/783)5.19(PREG_11_05/22.0)14.6] - 0.5 Tobit 83.4 0.396 115 1.91

DECD95 = [4.31(CONTDA/323)1.85(CSL10_85fm/6.04)2.15(OUTLETELEV/783)4.95(PREG_11_05/22.0)16.2] - 0.8 Tobit 82.3 0.376 107 0.76

JAND20 = 113(CONTDA/323)1.09(CSL10_85fm/6.04)0.38(OUTLETELEV/783)1.32(PREG_11_05/22.0)7.48 OLS 86.4 0.239 58.7 59.7

JAND50 = 34.1(CONTDA/323)1.45(CSL10_85fm/6.04)1.05(OUTLETELEV/783)2.81(PREG_11_05/22.0)9.42 OLS 86.7 0.273 69.1 20.5JAND80 = 9.48(CONTDA/323)2.05(CSL10_85fm/6.04)2.11(OUTLETELEV/783)4.78(PREG_11_05/22.0)12.0 OLS 84.9 0.364 102 5.04JAND90 = [4.20(CONTDA/323)2.36(CSL10_85fm/6.04)2.86(OUTLETELEV/783)5.26(PREG_11_05/22.0)16.3] - 0.07 OLS 85.0 0.421 125 2.41

JAND95 = [3.73(CONTDA/323)2.01(CSL10_85fm/6.04)2.24(OUTLETELEV/783)5.37(PREG_11_05/22.0)16.4] - 0.4 Tobit 84.0 0.426 128 1.22

FEBD20 = 143(CONTDA/323)1.00(CSL10_85fm/6.04)0.16(OUTLETELEV/783)0.89(PREG_11_05/22.0)6.69 OLS 88.8 0.210 50.6 85.0

FEBD50 = 44.1(CONTDA/323)1.32(CSL10_85fm/6.04)0.84(OUTLETELEV/783)2.31(PREG_11_05/22.0)9.13 OLS 87.2 0.254 63.9 25.4FEBD80 = 13.0(CONTDA/323)1.79(CSL10_85fm/6.04)1.69(OUTLETELEV/783)3.70(PREG_11_05/22.0)11.5 OLS 85.4 0.334 90.6 8.87FEBD90 = [7.13(CONTDA/323)2.02(CSL10_85fm/6.04)2.19(OUTLETELEV/783)4.89(PREG_11_05/22.0)13.4] - 0.1 OLS 83.1 0.399 116 3.63

FEBD95 = [3.97(CONTDA/323)2.51(CSL10_85fm/6.04)3.00(OUTLETELEV/783)6.48(PREG_11_05/22.0)16.1] - 0.08 Tobit 75.6 0.650 262 1.62

MARD20 = 253(CONTDA/323)1.05(CSL10_85fm/6.04)0.10(OUTLETELEV/783)0.27(PREG_11_05/22.0)5.82 OLS 88.2 0.212 51.3 177

MARD50 = 72.8(CONTDA/323)1.30(CSL10_85fm/6.04)0.61(OUTLETELEV/783)1.76(PREG_11_05/22.0)8.99 OLS 90.3 0.198 47.6 33.5MARD80 = 19.4(CONTDA/323)1.71(CSL10_85fm/6.04)1.37(OUTLETELEV/783)3.68(PREG_11_05/22.0)12.6 OLS 90.0 0.248 61.7 10.2
126 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 10. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 30 streamflow gaging stations in Region 2. —Continued

[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent 

of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx 

percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; CSL10_85fm, channel slope between points 10 and 85 percent of the stream 

length starting from the gage and along the longest flow path, in feet per mile; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches] 

Regression Equation1 Method Adjusted R2 (%)

Standard 

error of 

estimate in 

log 10 units 

of ft3/s

Standard error 

of estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

MARD90 = 8.89(CONTDA/323)2.23(CSL10_85fm/6.04)2.38(OUTLETELEV/783)5.57(PREG_11_05/22.0)14.5 OLS 78.1 0.456 142 4.44

MARD95 = [4.19(CONTDA/323)2.84(CSL10_85fm/6.04)3.44(OUTLETELEV/783)7.43(PREG_11_05/22.0)18.0] - 0.02 OLS 70.0 0.661 270 1.86

APRD20 = 260(CONTDA/323)0.97(CSL10_85fm/6.04)0.02(OUTLETELEV/783)0.14(PREG_11_05/22.0)5.31 OLS 86.7 0.241 59.5 193

APRD50 = 82.2(CONTDA/323)1.18(CSL10_85fm/6.04)0.50(OUTLETELEV/783)1.30(PREG_11_05/22.0)8.37 OLS 87.9 0.239 58.7 43.6APRD80 = 23.8(CONTDA/323)1.49(CSL10_85fm/6.04)1.00(OUTLETELEV/783)3.19(PREG_11_05/22.0)12.0 OLS 89.8 0.255 63.9 12.8APRD90 = 11.6(CONTDA/323)1.76(CSL10_85fm/6.04)1.45(OUTLETELEV/783)3.94(PREG_11_05/22.0)14.2 OLS 87.5 0.326 87.6 5.86APRD95 = [6.18(CONTDA/323)2.15(CSL10_85fm/6.04)2.28(OUTLETELEV/783)4.97(PREG_11_05/22.0)16.9] - 0.05 OLS 81.2 0.470 149 3.22

MAYD20 = 336(CONTDA/323)1.22(CSL10_85fm/6.04)0.36(OUTLETELEV/783)0.30(PRECIPOUT/41.3)3.20 OLS 96.6 0.125 29.1 259

MAYD50 = 86.4(CONTDA/323)1.50(CSL10_85fm/6.04)1.02(OUTLETELEV/783)1.39(PRECIPOUT/41.3)7.29 OLS 94.0 0.175 41.7 49.7MAYD80 = 29.0(CONTDA/323)1.81(CSL10_85fm/6.04)1.63(OUTLETELEV/783)2.39(PRECIPOUT/41.3)11.1 OLS 91.4 0.237 58.0 16.0MAYD90 = 16.3(CONTDA/323)1.98(CSL10_85fm/6.04)1.95(OUTLETELEV/783)2.52(PRECIPOUT/41.3)13.7 OLS 90.1 0.278 70.6 8.08MAYD95 = 9.14(CONTDA/323)2.19(CSL10_85fm/6.04)2.38(OUTLETELEV/783)2.55(PRECIPOUT/41.3)18.2 OLS 90.5 0.312 82.5 4.46JUND20 = 253(CONTDA/323)1.23(CSL10_85fm/6.04)0.17(OUTLETELEV/783)1.33(PRECIPOUT/41.3)3.41 OLS 94.6 0.170 40.2 202JUND50 = 60.3(CONTDA/323)1.69(CSL10_85fm/6.04)1.17(OUTLETELEV/783)2.38(PRECIPOUT/41.3)7.44 OLS 92.4 0.215 52.1 37.1JUND80 = 18.4(CONTDA/323)2.09(CSL10_85fm/6.04)2.01(OUTLETELEV/783)3.61(PRECIPOUT/41.3)11.5 OLS 89.4 0.290 75.0 9.48JUND90 = [10.2(CONTDA/323)2.25(CSL10_85fm/6.04)2.42(OUTLETELEV/783)4.35(PRECIPOUT/41.3)14.4] - 0.1 OLS 87.2 0.348 95.8 4.49

JUND95 = [6.15(CONTDA/323)2.38(CSL10_85fm/6.04)2.80(OUTLETELEV/783)4.04(PRECIPOUT/41.3)19.3] - 0.2 Tobit 85.4 0.434 131 2.91

JULD20 = 81.8(CONTDA/323)1.58(CSL10_85fm/6.04)0.86(OUTLETELEV/783)2.17(PRECIPOUT/41.3)8.24 OLS 91.1 0.236 58.0 47.7

JULD50 = [26.1(CONTDA/323)1.78(CSL10_85fm/6.04)1.65(OUTLETELEV/783)3.53(PRECIPOUT/41.3)11.5] - 1 OLS 92.0 0.221 53.6 11.5

JULD80 = [7.77(CONTDA/323)2.73(CSL10_85fm/6.04)3.12(OUTLETELEV/783)4.79(PRECIPOUT/41.3)18.5] - 0.05 OLS 78.7 0.562 201 3.78

JULD90 = [5.30(CONTDA/323)2.55(CSL10_85fm/6.04)3.06(OUTLETELEV/783)5.31(PRECIPOUT/41.3)20.4] - 0.3 Tobit 80.8 0.522 177 1.21JULD95 = [3.93(CONTDA/323)2.30(CSL10_85fm/6.04)2.78(OUTLETELEV/783)5.12(PRECIPOUT/41.3)19.4] - 0.5 Tobit 79.4 0.497 163 0.53
Tables 127

Table 10. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 30 streamflow gaging stations in Region 2. —Continued[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent 

of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded xx 

percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; CSL10_85fm, channel slope between points 10 and 85 percent of the stream 

length starting from the gage and along the longest flow path, in feet per mile; OUTLETELEV, gage elevation, in feet above North American Vertical Datum of 1988; PREG_11_05, winter-spring precipitation defined as the mean monthly precipitation for November through May at the gage, in inches; PRECIPOUT, mean annual precipitation at the gage, in inches] 

Regression Equation1 Method Adjusted R2 (%)

Standard 

error of 

estimate in 

log 10 units 

of ft3/s

Standard error 

of estimate as 

percent (%)

Median 

Statistic 

(ft3/s)

AUGD20 = 36.8(CONTDA/323)1.81(CSL10_85fm/6.04)1.33(OUTLETELEV/783)2.60(PRECIPOUT/41.3)8.82 OLS 88.0 0.294 76.5 18.5

AUGD50 = [12.6(CONTDA/323)2.21(CSL10_85fm/6.04)2.33(OUTLETELEV/783)4.09(PRECIPOUT/41.3)14.4] - 0.2 OLS 86.4 0.354 98.0 7.04

AUGD80 = [5.27(CONTDA/323)2.53(CSL10_85fm/6.04)3.08(OUTLETELEV/783)5.01(PRECIPOUT/41.3)20.4] - 0.3 Tobit 79.5 0.525 179 1.38AUGD90 = [4.01(CONTDA/323)2.27(CSL10_85fm/6.04)2.80(OUTLETELEV/783)4.87(PRECIPOUT/41.3)19.2] - 0.5 Tobit 77.9 0.509 170 0.46AUGD95 = [1.83(CONTDA/323)2.44(CSL10_85fm/6.04)3.12(OUTLETELEV/783)5.83(PRECIPOUT/41.3)23.3] - 0.2 Tobit 76.4 0.560 200 0.03SEPD20 = 53.5(CONTDA/323)1.36(CSL10_85fm/6.04)0.68(OUTLETELEV/783)1.38(PRECIPOUT/41.3)6.14 OLS 90.3 0.216 52.1 32.7

SEPD50 = [12.8(CONTDA/323)2.08(CSL10_85fm/6.04)2.24(OUTLETELEV/783)3.85(PRECIPOUT/41.3)12.8] - 0.3 OLS 85.3 0.343 93.6 6.91

SEPD80 = [5.00(CONTDA/323)2.49(CSL10_85fm/6.04)3.08(OUTLETELEV/783)4.76(PRECIPOUT/41.3)20.1] - 0.3 Tobit 78.1 0.548 192 1.28SEPD90 = [3.41(CONTDA/323)2.10(CSL10_85fm/6.04)2.58(OUTLETELEV/783)4.48(PRECIPOUT/41.3)19.5] - 0.5 Tobit 75.0 0.514 172 0.24SEPD95 = [0.96(CONTDA/323)2.39(CSL10_85fm/6.04)3.18(OUTLETELEV/783)4.09(PRECIPOUT/41.3)29.9] - 0.2 Tobit 65.6 0.646 259 0.02

1Final units of all computations from regression equations are in cubic feet per second (ft3/s). Definition and naming conventions for statistics follow that of USGS StreamStats (http://water.usgs.gov/

osw/streamstats/StatisticsDefinitions.html accessed September 10, 2009).
128 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 11. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 51 streamflow gaging stations in Region 3. —Continued

[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded 

xx percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent 

variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; PRECIPOUT, mean annual precipitation at the gage, in inches; 

CANOPY_PCT, percentage of drainage-basin that is forested; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, summer-autumn precipitation defined 

as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; DECAVPRE, mean December precipitation at the gage, in inches]

Regression Equation 1 Method Adjusted R2 (%)

Standard error 

of estimate in 

log 10 units of 

ft3/s

Standard error 

of estimate as 

percent 

(%)

Median

Statistic

 (ft3/s)

Annual Mean Flow

AVE_DV = 203(CONTDA/203)1.02(PRECIPOUT/47.8)4.51 OLS 98.8 0.073 18.0 251

Flow Duration Statistics

D20 = 197.8(CONTDA/203)1.09(CANOPY_PCT/40.8)-0.11(ELEV/1010)0.74(PRECIPOUT/47.8)6.27 OLS 97.3 0.115 26.9 250

D50 = 48.9(CONTDA/203)1.13(CANOPY_PCT/40.8)-0.73(ELEV/1010)1.83(PRECIPOUT/47.8)8.53 OLS 92.8 0.178 42.4 58.1D80 = [9.39(CONTDA/203)1.32(CANOPY_PCT/40.8)-2.07(ELEV/1010)3.24(PRECIPOUT/47.8)11.7] - 0.1 OLS 83.8 0.318 84.7 9.83

D90 = [4.87(CONTDA/203)1.30(CANOPY_PCT/40.8)-2.67(ELEV/1010)3.47(PRECIPOUT/47.8)12.6] - 0.3 Tobit 75.7 0.390 112 3.30

D95 = [3.01(CONTDA/203)1.22(CANOPY_PCT/40.8)-3.12(ELEV/1010)3.99(PRECIPOUT/47.8)14.6] - 0.4 Tobit 68.0 0.461 145 1.26D20SUM = 72.5(CONTDA/203)1.17(CANOPY_PCT/40.8)-0.51(ELEV/1010)0.82(PREG_06_10/20.2)8.22 OLS 96.5 0.127 29.9 71.2

D50SUM = 17.1(CONTDA/203)1.22(CANOPY_PCT/40.8)-1.24(ELEV/1010)1.66(PREG_06_10/20.2)12.0 OLS 90.7 0.227 55.8 19.3D80SUM = [5.32(CONTDA/203)1.29(CANOPY_PCT/40.8)-2.13(ELEV/1010)1.81(PREG_06_10/20.2)18.5] - 0.2 Tobit 78.5 0.425 128 3.48

D90SUM = [2.21(CONTDA/203)1.41(CANOPY_PCT/40.8)-2.98(ELEV/1010)1.77(PREG_06_10/20.2)28.3] - 0.05 Tobit 74.5 0.603 228 1.15D95SUM = [1.20(CONTDA/203)1.20(CANOPY_PCT/40.8)-3.63(ELEV/1010)2.00(PREG_06_10/20.2)34.4] - 0.07 Tobit 75.7 0.721 320 0.33

D20WSP = 283(CONTDA/203)1.07(CANOPY_PCT/40.8)0.04(ELEV/1010)0.41(PRECIPOUT/47.8)6.35 OLS 97.2 0.120 28.4 357

D50WSP= 92.7(CONTDA/203)1.06(CANOPY_PCT/40.8)-0.29(ELEV/1010)1.31(PRECIPOUT/47.8)8.27 OLS 93.0 0.177 41.7 108D80WSP= 27.9(CONTDA/203)1.17(CANOPY_PCT/40.8)-0.95(ELEV/1010)2.35(PRECIPOUT/47.8)11.6 OLS 88.7 0.237 58.0 35.0D90WSP= [13.5(CONTDA/203)1.28(CANOPY_PCT/40.8)-1.48(ELEV/1010)3.22(PRECIPOUT/47.8)14.0] - 0.07 OLS 85.9 0.291 75.0 17.3D95WSP= [8.61(CONTDA/203)1.17(CANOPY_PCT/40.8)-1.8(ELEV/1010)3.06(PRECIPOUT/47.8)12.8] - 0.6 Tobit 77.1 0.303 79.5 9.3

OCTD20 = 68.7(CONTDA/203)1.09(CANOPY_PCT/40.8)-0.33(PREG_06_10/20.2)9.73 OLS 94.0 0.168 39.5 60.6

OCTD50 = 15.7(CONTDA/203)1.10(CANOPY_PCT/40.8)-1.30(PREG_06_10/20.2)15.8 OLS 84.2 0.287 74.3 15.9OCTD80 = [4.07(CONTDA/203)1.25(CANOPY_PCT/40.8)-2.82(PREG_06_10/20.2)23.5] - 0.1 Tobit 66.3 0.584 214 2.45

OCTD90 = [1.93(CONTDA/203)1.19(CANOPY_PCT/40.8)-3.28(PREG_06_10/20.2)30.7] - 0.1 Tobit 71.8 0.630 247 0.65OCTD95 = [1.16(CONTDA/203)1.02(CANOPY_PCT/40.8)-3.65(PREG_06_10/20.2)35.7] - 0.1 Tobit 71.6 0.694 297 0.19
Tables 129

Table 11. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 51 streamflow gaging stations in Region 3. —Continued[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded 

xx percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent 

variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; PRECIPOUT, mean annual precipitation at the gage, in inches; 

CANOPY_PCT, percentage of drainage-basin that is forested; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, summer-autumn precipitation defined 

as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; DECAVPRE, mean December precipitation at the gage, in inches]

Regression Equation 1 Method Adjusted R2 (%)

Standard error 

of estimate in 

log 10 units of 

ft3/s

Standard error 

of estimate as 

percent 

(%)

Median

Statistic

 (ft3/s)

NOVD20 = 159(CONTDA/203)1.08(CANOPY_PCT/40.8)-0.21(ELEV/1010)1.43(PRECIPOUT/47.8)7.98 OLS 91.6 0.194 46.2 170

NOVD50 = 35.7(CONTDA/203)1.16(CANOPY_PCT/40.8)-0.99(ELEV/1010)2.56(PRECIPOUT/47.8)10.3 OLS 88.4 0.248 61.7 39.2NOVD80 = 7.84(CONTDA/203)1.55(CANOPY_PCT/40.8)-2.61(ELEV/1010)4.82(PRECIPOUT/47.8)16.5 OLS 71.1 0.554 196 8.74NOVD90 = [4.92(CONTDA/203)1.30(CANOPY_PCT/40.8)-2.86(ELEV/1010)3.53(PRECIPOUT/47.8)14.3] - 0.09 OLS 71.6 0.499 165 3.88

NOVD95 = [3.40(CONTDA/203)1.15(CANOPY_PCT/40.8)-3.10(ELEV/1010)4.26(PRECIPOUT/47.8)14.3] - 0.4 Tobit 66.5 0.524 178 1.71

DECD20 = 202.5(CONTDA/203)0.97(CANOPY_PCT/40.8)0.00(ELEV/1010)1.15(DECAVPRE/3.51)3.29 OLS 94.1 0.161 38.0 282

DECD50 = 63.2(CONTDA/203)1.02(CANOPY_PCT/40.8)-0.53(ELEV/1010)2.45(DECAVPRE/3.51)4.10 OLS 89.6 0.215 52.1 73.6DECD80 = [19.1(CONTDA/203)1.13(CANOPY_PCT/40.8)-1.19(ELEV/1010)3.83(DECAVPRE/3.51)4.76] - 0.3 Tobit 83.6 0.293 75.8 22.2

DECD90 = [9.60(CONTDA/203)1.18(CANOPY_PCT/40.8)-1.80(ELEV/1010)4.01(DECAVPRE/3.51)5.25] - 0.4 Tobit 76.7 0.326 87.6 10.1DECD95 = [6.21(CONTDA/203)1.20(CANOPY_PCT/40.8)-2.17(ELEV/1010)4.22(DECAVPRE/3.51)5.11] - 0.3 Tobit 71.6 0.406 119 4.58

JAND20 = 214(CONTDA/203)0.99(CANOPY_PCT/40.8)-0.06(ELEV/1010)1.12(DECAVPRE/3.51)3.30 OLS 93.7 0.164 38.7 284

JAND50 = 77.3(CONTDA/203)1.05(CANOPY_PCT/40.8)-0.36(ELEV/1010)2.03(DECAVPRE/3.51)3.82 OLS 91.6 0.199 47.6 96.4JAND80 = [27.4(CONTDA/203)1.08(CANOPY_PCT/40.8)-0.92(ELEV/1010)2.80(DECAVPRE/3.51)4.75] - 0.4 OLS 87.1 0.248 61.7 32.5

JAND90 = [13.8(CONTDA/203)1.13(CANOPY_PCT/40.8)-1.27(ELEV/1010)3.64(DECAVPRE/3.51)5.10] - 0.3 OLS 86.4 0.270 68.4 17.2JAND95 = [8.60(CONTDA/203)1.12(CANOPY_PCT/40.8)-1.60(ELEV/1010)4.05(DECAVPRE/3.51)5.06] - 0.6 Tobit 76.5 0.295 76.5 7.46

FEBD20 = 267(CONTDA/203)1.09(CANOPY_PCT/40.8)0.02(ELEV/1010)0.18(PRECIPOUT/47.8)7.60 OLS 95.4 0.154 36.5 411

FEBD50 = 104(CONTDA/203)1.07(CANOPY_PCT/40.8)-0.28(ELEV/1010)1.07(PRECIPOUT/47.8)9.23 OLS 91.7 0.195 46.9 130

FEBD80 = 37.6(CONTDA/203)1.14(CANOPY_PCT/40.8)-0.69(ELEV/1010)1.76(PRECIPOUT/47.8)11.7 OLS 88.6 0.238 58.7 43.6FEBD90 = 21.5(CONTDA/203)1.25(CANOPY_PCT/40.8)-1.05(ELEV/1010)2.31(PRECIPOUT/47.8)14.2 OLS 85.1 0.298 78.0 23.9FEBD95 = [15.2(CONTDA/203)1.15(CANOPY_PCT/40.8)-1.09(ELEV/1010)2.06(PRECIPOUT/47.8)13.3] - 0.4 OLS 87.7 0.243 60.2 15.2

MARD20 = 377(CONTDA/203)1.02(CANOPY_PCT/40.8)0.14(PRECIPOUT/47.8)5.80 OLS 95.9 0.146 34.3 489

MARD50 = 140(CONTDA/203)0.97(CANOPY_PCT/40.8)-0.13(PRECIPOUT/47.8)7.78 OLS 90.7 0.202 48.4 167MARD80 = 55.9(CONTDA/203)1.01(CANOPY_PCT/40.8)-0.57(PRECIPOUT/47.8)10.8 OLS 86.0 0.249 61.7 59.4
130 Methods for Estimating Flow-Duration and Annual Mean-Flow Statistics for Ungaged Streams in Oklahoma Table 11. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 51 streamflow gaging stations in Region 3. —Continued

[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded 

xx percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent 

variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; PRECIPOUT, mean annual precipitation at the gage, in inches; 

CANOPY_PCT, percentage of drainage-basin that is forested; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, summer-autumn precipitation defined 

as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; DECAVPRE, mean December precipitation at the gage, in inches]

Regression Equation 1 Method Adjusted R2 (%)

Standard error 

of estimate in 

log 10 units of 

ft3/s

Standard error 

of estimate as 

percent 

(%)

Median

Statistic

 (ft3/s)

MARD90 = 32.2(CONTDA/203)1.03(CANOPY_PCT/40.8)-0.81(PRECIPOUT/47.8)12.5 OLS 83.4 0.280 71.3 30.5

MARD95 = [23.0(CONTDA/203)0.93(CANOPY_PCT/40.8)-0.84(PRECIPOUT/47.8)11.7] - 1 OLS 80.5 0.275 70.6 20.6

APRD20 = 382(CONTDA/203)1.10(ELEV/1010)-0.06(PRECIPOUT/47.8)5.48 OLS 96.1 0.146 34.3 445

APRD50 = 135(CONTDA/203)1.04(ELEV/1010)1.10(PRECIPOUT/47.8)6.03 OLS 93.6 0.177 41.7 132APRD80 = 56.0(CONTDA/203)1.02(ELEV/1010)1.85(PRECIPOUT/47.8)6.81 OLS 88.8 0.234 57.3 56.5APRD90 = 36.3(CONTDA/203)1.05(ELEV/1010)2.22(PRECIPOUT/47.8)7.41 OLS 86.7 0.260 65.4 34.9APRD95 = 24.7(CONTDA/203)1.09(ELEV/1010)2.59(PRECIPOUT/47.8)8.85 OLS 82.1 0.314 83.2 22.6MAYD20 = 399(CONTDA/203)1.15(CANOPY_PCT/40.8)0.08(ELEV/1010)0.15(PRECIPOUT/47.8)3.44 OLS 97.1 0.128 29.9 453MAYD50 = 119(CONTDA/203)1.19(CANOPY_PCT/40.8)-0.33(ELEV/1010)1.16(PRECIPOUT/47.8)5.17 OLS 94.9 0.163 38.0 120MAYD80 = 43.6(CONTDA/203)1.18(CANOPY_PCT/40.8)-0.73(ELEV/1010)1.95(PRECIPOUT/47.8)7.28 OLS 91.6 0.200 47.6 53.6MAYD90 = 27.6(CONTDA/203)1.21(CANOPY_PCT/40.8)-0.95(ELEV/1010)2.29(PRECIPOUT/47.8)8.89 OLS 88.2 0.240 59.5 35.9MAYD95 = 19.5(CONTDA/203)1.24(CANOPY_PCT/40.8)-1.15(ELEV/1010)2.47(PRECIPOUT/47.8)10.6 OLS 84.3 0.287 73.6 24.5JUND20 = 195(CONTDA/203)1.18(CANOPY_PCT/40.8)-0.26(ELEV/1010)0.65(PREG_06_10/20.2)5.87 OLS 94.1 0.171 40.2 204JUND50 = 55.6(CONTDA/203)1.20(CANOPY_PCT/40.8)-0.63(ELEV/1010)1.40(PREG_06_10/20.2)8.23 OLS 92.9 0.203 49.1 54.6JUND80 = 19.5(CONTDA/203)1.27(CANOPY_PCT/40.8)-1.04(ELEV/1010)2.09(PREG_06_10/20.2)12.4 OLS 86.1 0.299 78.0 22.8JUND90 = [12.0(CONTDA/203)1.23(CANOPY_PCT/40.8)-1.16(ELEV/1010)2.13(PREG_06_10/20.2)13.9] - 0.2 OLS 82.7 0.335 90.6 13.5

JUND95 = [8.32(CONTDA/203)1.21(CANOPY_PCT/40.8)-1.35(ELEV/1010)1.78(PREG_06_10/20.2)16.6] - 0.3 Tobit 78.8 0.361 101 6.91

JULD20 = 66.8(CONTDA/203)1.17(CANOPY_PCT/40.8)-0.73(ELEV/1010)1.25(PREG_06_10/20.2)8.29 OLS 93.6 0.166 38.7 73.1

JULD50 = 19.1(CONTDA/203)1.26(CANOPY_PCT/40.8)-1.33(ELEV/1010)2.10(PREG_06_10/20.2)11.5 OLS 87.6 0.272 69.1 20.0JULD80 = [7.13(CONTDA/203)1.31(CANOPY_PCT/40.8)-1.76(ELEV/1010)2.15(PREG_06_10/20.2)17.5] - 0.2 Tobit 81.8 0.394 114 4.31

JULD90 = [3.87(CONTDA/203)1.51(CANOPY_PCT/40.8)-2.39(ELEV/1010)1.86(PREG_06_10/20.2)25.5] - 0.05 Tobit 78.0 0.539 187 1.98JULD95 = [2.03(CONTDA/203)1.76(CANOPY_PCT/40.8)-3.11(ELEV/1010)1.99(PREG_06_10/20.2)31.4] - 0.01 Tobit 70.9 0.752 349 1.04
Tables 131

Table 11. Regression equations developed to estimate flow-duration statistics and annual mean-flow at 51 streamflow gaging stations in Region 3. —Continued[AVE_DV, annual mean from daily mean streamflow; Dxx, daily mean discharge which is exceeded xx percent of the time; DxxSUM, daily mean discharge from June 1 to October 31 exceeded xx percent of the time; DxxWSP, daily mean discharge from November 1 to May 31 exceeded xx percent of the time; OCTDxx, first three letters indicate the month where daily mean discharge is exceeded 

xx percent of the time; OLS, Ordinary Least Squares regression procedure; Tobit, Tobit Maximum Likelihood Estimator regression procedure; Median Statistic, median of flow statistic (dependent 

variable) used to develop regression equations]; ft3/s, cubic feet per second; CONTDA, contributing drainage area, in square miles; PRECIPOUT, mean annual precipitation at the gage, in inches; 

CANOPY_PCT, percentage of drainage-basin that is forested; ELEV, mean basin elevation, in feet above North American Vertical Datum of 1988; PREG_06_10, summer-autumn precipitation defined 

as the mean monthly precipitation for June through October at the gage, in inches; CSL10_85fm, channel slope between points 10 and 85 percent of the stream length starting from the gage and along the longest flow path, in feet per mile; DECAVPRE, mean December precipitation at the gage, in inches]

Regression Equation 1 Method Adjusted R2 (%)

Standard error 

of estimate in 

log 10 units of 

ft3/s

Standard error 

of estimate as 

percent 

(%)

Median

Statistic

 (ft3/s)

AUGD20 = 29.8(CONTDA/203)1.23(CANOPY_PCT/40.8)-1.10(ELEV/1010)1.20(PREG_06_10/20.2)10.5 OLS 91.1 0.208 49.9 31.0

AUGD50 = [12.6(CONTDA/203)1.03(CANOPY_PCT/40.8)-1.40(ELEV/1010)1.50(PREG_06_10/20.2)11.3] - 1 OLS 86.5 0.246 61.0 9.71

AUGD80 = [3.44(CONTDA/203)1.34(CANOPY_PCT/40.8)-2.51(ELEV/1010)1.98(PREG_06_10/20.2)22.0] - 0.1 Tobit 75.5 0.550 194 1.81

AUGD90 = [1.77(CONTDA/203)1.22(CANOPY_PCT/40.8)-3.28(ELEV/1010)1.76(PREG_06_10/20.2)29.7] - 0.09 Tobit 77.0 0.669 277 0.44

AUGD95 = [0.70(CONTDA/203)1.28(CANOPY_PCT/40.8)-3.92(ELEV/1010)2.98(PREG_06_10/20.2)36.3] - 0.04 Tobit 76.5 0.817 417 0.11

SEPD20 = 41.5(CONTDA/203)1.12(CANOPY_PCT/40.8)-0.81(PREG_06_10/20.2)9.91 OLS 94.2 0.155 36.5 40.4

SEPD50 = 10.4(CONTDA/203)1.29(CANOPY_PCT/40.8)-1.92(PREG_06_10/20.2)18.4 OLS 82.1 0.370 104 9.40SEPD80 = [3.19(CONTDA/203)1.37(CANOPY_PCT/40.8)-2.96(PREG_06_10/20.2)27.0] - 0.06 Tobit 73.9 0.560 200 1.61

SEPD90 = [1.65(CONTDA/203)1.03(CANOPY_PCT/40.8)-3.32(PREG_06_10/20.2)32.1] - 0.2 Tobit 72.3 0.597 223 0.31SEPD95 = [0.90(CONTDA/203)1.13(CANOPY_PCT/40.8)-3.92(PREG_06_10/20.2)39.5] - 0.09 Tobit 71.9 0.799 397 0.05

1Final units of all computations from regression equations are in cubic feet per second (ft3/s). Definition and naming conventions for statistics follow that of USGS StreamStats (http://water.usgs.

gov/osw/streamstats/StatisticsDefinitions.html accessed September 10, 2009).