Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20Th Century in Oklahoma

Prepared in cooperation with the Oklahoma Water Resources Board

Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

• ....

Canadian River near Norman February 1952

-,.

Canadian River downstream from State Highway. 99" or' near Ada August 16, 2006.. Scientific Investigations Report 2008-5199

U.S. Department of the Interior U.S. Geological Survey Front Cover: Picture One shows wind ripples and river silts, Canadian River near Norman, Cleveland County, Okla- homa, taken February 1952. Photographer: W.B. Hamilton, from U.S. Geological Survey Photographic Library.

Picture Two shows the dry Canadian River near Ada, Pontotoc County, Oklahoma, downstream from State High- way 99, taken August 16, 2006. Photographer: Daniel Fenner, U.S. Fish and Wildlife Service. Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods Of the 20th Century in Oklahoma

By Robert L. Tortorelli

Prepared in cooperation with the Oklahoma Water Resources Board

Scientific Investigations Report 2008–5199

U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2008

This and other USGS information products are available at: http://store.usgs.gov/ U.S. Geological Survey Box 25286, Denver Federal Center Denver, CO 80225 To learn about the USGS and its information products visit http://www.usgs.gov/ 1-888-ASK-USGS

Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to reproduce any copyrighted materials contained within this report.

Suggested citation: Tortorelli, R.L., 2008, Hydrologic drought of Water Year 2006 compared with four major drought periods of the 20th century in Oklahoma: U.S. Geological Survey Scientific Investigations Report 2008–5199, 46 p. iii

Contents

Abstract ...... 1 Introduction...... 1 Purpose and Scope ...... 2 Progression of Drought ...... 2 Definition of Drought Sequence ...... 2 Drought Monitor ...... 2 Statewide Precipitation and Streamflow ...... 2 Acknowledgments ...... 7 Precipitation by Climate Division ...... 7 Climate Division 1 Panhandle ...... 12 Climate Division 2 North Central ...... 12 Climate Division 3 Northeast ...... 12 Climate Division 4 West Central ...... 12 Climate Division 5 Central ...... 14 Climate Division 6 East Central ...... 14 Climate Division 7 Southwest ...... 14 Climate Division 8 South Central ...... 14 Climate Division 9 Southeast ...... 14 Streamflow of Long-Term Sites ...... 14 Salt Fork Arkansas River at Tonkawa ...... 14 Chikaskia River near Blackwell ...... 14 Cimarron River near Waynoka ...... 27 Cimarron River near Ripley ...... 27 Illinois River near Tahlequah ...... 27 Canadian River at Calvin ...... 27 North Canadian River near Wetumka ...... 27 Salt Fork Red River at Mangum ...... 27 Red River near Gainesville, Texas ...... 27 Washita River near Dickson ...... 28 Blue River near Blue...... 28 Red River at Arthur City, Texas ...... 28 Effects of Low Streamflows ...... 28 Conditions at Major Reservoirs ...... 28 Hydroelectric Power Generation ...... 28 Ground Water at a Long-Term Site ...... 34 Wildfires ...... 34 Summary...... 34 Selected References ...... 36 Appendixes ...... 39 1–7. Photographs showing: 1. Salt Fork of Arkansas River at Tonkawa (0751000), showing low flow, 30 cubic feet per second, looking upstream from U.S. Highway 77 bridge, August 6, 2006...... 41 iv

2. Chikaskia River near Blackwell (07152000), showing low flow, 74 cubic feet per second, looking downstream from State Highway 11 bridge, August 6, 2006...... 41 3. Cimarron River near Waynoka (07158000), showing low flow, 0.17 cubic foot per second, looking downstream from U.S. Highway 281 bridge, August 9, 2006...... 42 4. Cimarron River near Ripley (07161450), showing low flow, 55 cubic feet per second, looking upstream toward State Highway 33 bridge, August 11, 2006...... 42 5. Canadian River upstream to downstream, August 11, 2006: (A) near Thomas, showing no flow, looking upstream from State Highway 33 bridge (B) at Bridgeport (07228500), showing low flow and pools, 2.9 cubic feet per second, looking upstream from U.S. Highway 281 bridge...... 43 5. Canadian River upstream to downstream, August 11, 2006: (C) near Union City, showing no flow and pools, looking upstream from State Highway 81 bridge (D) at Purcell (07229200), showing low flow and pools, 4.2 cubic feet per second, looking upstream from U.S. Highway 77 bridge...... 44 5. Canadian River upstream to downstream: (E) near Wanette, showing no flow, looking upstream from State Highway 102 bridge, August 11, 2006 (F) near Ada, showing no flow, looking downstream from State Highway 99 bridge, August 16, 2006...... 45 6. Washita River near Dickson (07331000), showing low flow and pools, 5.7 cubic feet per second, looking downstream from U.S. Highway 177 bridge, August 22, 2006...... 46 7. Lake Altus at Lugert (07302500), showing very low lake elevation, 7.7 percent of conservation storage, looking upstream from dam, August 22, 2006...... 46

Figures

1. Sequence of drought development ...... 3 2. Maps showing monthly Drought Monitor Graphs, November 1, 2005, through October 3, 2006 ...... 4 3–4. Graphs showing: 3. Oklahoma statewide precipitation showing the annual departure from the long-term statewide median of 33.51 inches and a 5-year weighted average line for water years 1925–2006...... 6 4. Oklahoma statewide runoff showing the annual departure from the long-term statewide median of 3 inches and a 5-year weighted average line for water years 1925–2006...... 6 5. Maps showing regional streamflow patterns Water Year 2006...... 8 6. Map showing percentage of stations below normal streamflow since January 16, 2001, through February 1, 2008, in Oklahoma ...... 9 7. Map showing National Weather Service Climate Divisions in Oklahoma...... 12 8–9. Maps showing: 8. Oklahoma (A) percent of normal rainfall, Water Year 2006 (B) departure from normal rainfall, Water Year 2006 ...... 13 9. Selected long-term streamflow-gaging stations in Oklahoma and Canadian River photograph locations...... 15 v

10–21. Graphs showing: 10. Salt Fork Arkansas River at Tonkawa (A) annual departure from long-term median annual streamflow, water years 1942–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1942–2006...... 18 11. Chikaskia River near Blackwell (A) annual departure from long-term median annual streamflow, water years 1937–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1937–2006...... 19 12. Cimarron River near Waynoka (A) annual departure from long-term median annual streamflow, water years 1938–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1938–2006...... 20 13. Cimarron River near Ripley (A) annual departure from long-term median annual streamflow, water years 1940–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1940–2006. Includes streamflow record 1940–87 from nearby station 0716100, Cimarron River at Perkins...... 21 14. Illinois River near Tahlequah (A) annual departure from long-term median annual streamflow, water years 1936–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1936–2006...... 22 15. Canadian River at Calvin (A) annual departure from long-term median annual streamflow, water years 1939–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1939–2006...... 23 16. North Canadian River near Wetumka (A) annual departure from long-term median annual streamflow, water years 1938–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1938–2006...... 24 17. Salt Fork Red River at Mangum (A) annual departure from long-term median annual streamflow, water years 1938–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1938–2006...... 25 18. Red River near Gainesville, Texas, (A) annual departure from long-term median annual streamflow, water years 1937–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1937–2006...... 26 19. Washita River near Dickson (A) annual departure from long-term median annual streamflow, water years 1929–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1929–2006...... 29 20. Blue River near Blue (A) annual departure from long-term median annual streamflow, water years 1937–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1937–2006...... 30 21. Red River at Arthur City, Texas, (A) annual departure from long-term median annual streamflow, water years 1945–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1945–2006...... 31 vi

22. Map showing locations of selected major lakes and reservoirs in Oklahoma and percent of Conservation Storage as of October 4, 2006...... 32 23. Graph showing Fittstown ground-water well, comparing daily water levels for Water Year 2006 and long-term mean-daily water levels, water years 1981–2006...... 36

Tables

1. Summary of precipitation at Climate Divisions in Oklahoma comparing the median of mean annual precipitation during water years 1925-2006 with average annual precipitation during periods of previous documented hydrologic droughts and the recent hydrologic drought period...... 10 2. Summary of streamflow conditions at selected long-term streamflow-gaging stations in Oklahoma comparing the median of mean annual streamflow with average annual streamflow during periods of previous documented hydrologic droughts and the recent hydrologic drought period...... 16 3. Storage in selected major Oklahoma lakes and reservoirs during October 4, 2006, by National Weather Service Climate Division, and comparison with December 21, 2005, and May 24, 2006, storage...... 33 4. Comparison of hydroelectric power generation at selected Oklahoma hydroelectric plants between Calendar Year 2005 and Water Year 2006...... 35

Conversion Factors and Datums

Multiply By To obtain Length inch (in.) 2.54 centimeter (cm) inch (in.) 25.4 millimeter (mm) foot (ft) 0.3048 meter (m) Area square mile (mi2) 2.590 square kilometer (km2) Volume acre-foot (acre-ft) 1,233 cubic meter (m3) Flow rate cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s) Energy gigawatt-hour (GWh) 3.6 x 1012 joule (J)

Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88). Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83). Altitude, as used in this report, refers to distance above the vertical datum. Water year is the 12-month period October 1 through September 30, designated by the calendar year in which the water year ends. Hydrologic Drought of Water Year 2006 Compared With Four Major Drought Periods of the 20th Century In Oklahoma

By Robert L. Tortorelli

Abstract drought worsened going from north to south in Oklahoma, ranging from 45 percent in the north, to just 14 percent in east- central Oklahoma, and 20 percent of normal annual stream- Water Year 2006 (October 1, 2005, to September 30, flow in the southwest. 2006) was a year of extreme hydrologic drought and the dri- The low streamflows resulted in only 86.3 percent of est year in the recent 2002–2006 drought in Oklahoma. The the statewide conservation storage available at the end of the severity of this recent drought can be evaluated by compar- water year in major reservoirs, and 7 to 47 percent of hydro- ing it with four previous major hydrologic droughts, water electric power generation at sites in Oklahoma in Calendar years 1929–41, 1952–56, 1961–72, and 1976–81. The U.S. Year 2005. Geological Survey, in cooperation with the Oklahoma Water Resources Board, completed an investigation to summarize the Water Year 2006 hydrologic drought and compare it to the four previous major hydrologic droughts in the 20th century. Introduction The period of water years 1925–2006 was selected as the period of record because before 1925 few continuous record Water Year 2006 (October 1, 2005, to September 30, streamflow-gaging sites existed and gaps existed where no 2006) was a year of extreme hydrologic drought and the driest streamflow-gaging sites were operated. Statewide annual pre- year in the recent 2002–2006 drought in Oklahoma. A sense of cipitation in Water Year 2006 was second driest and statewide the severity of this recent drought can be evaluated by compar- annual runoff in Water Year 2006 was sixth driest in the ing Water Year 2006 hydrologic drought with four previous 82 years of record. major hydrologic droughts, water years 1929–41, 1952–56, Annual area-averaged precipitation totals by the nine 1961–72, and 1976–81. The effect of the drought varies in National Weather Service Climate Divisions from Water Year different regions of the state. Data from several long-term 2006 are compared to those during four previous major hydro- streamflow-gaging stations are available to assess the effect of logic droughts to show how rainfall deficits in Oklahoma var- the hydrologic drought of Water Year 2006 in Oklahoma. ied by region. Only two of the nine climate divisions, Climate Hydrologic drought is associated with the effects of Division 1 Panhandle and Climate Division 4 West Central, periods of precipitation deficits on surface or subsurface water had minor rainfall deficits, while the rest of the climate divi- supply. The frequency and severity of hydrologic drought sions had severe rainfall deficits in Water Year 2006 ranging is defined on a watershed or river basin scale. Water in the from only 65 to 73 percent of normal annual precipitation. hydrologic storage systems, rivers and reservoirs, commonly Regional streamflow patterns for Water Year 2006 indi- has multiple and competing purposes including flood control, cate that Oklahoma was part of the regionwide below-normal irrigation, recreation, navigation, hydropower, and wildlife streamflow conditions for Arkansas-White-Red River Basin, habitat. Competition for this water escalates during drought, the sixth driest since 1930. The percentage of long-term sta- and conflicts between water users increase substantially tions in Oklahoma (with at least 30 years of record) having (National Drought Mitigation Center, 2006a). below-normal streamflow reached 80 to 85 percent for some The U.S. Geological Survey (USGS), in cooperation with days in August and November 2006. the Oklahoma Water Resources Board, completed an investi- Twelve long-term streamflow-gaging sites with periods gation to summarize the Water Year 2006 hydrologic drought of record ranging from 62 to 78 years were selected to show and compare it to the four previous major hydrologic droughts how streamflow deficits varied by region. The hydrologic in the 20th century. 2 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Purpose and Scope November 1, 2005, to October 3, 2006. The hydrologic drought of Water Year 2006 in Oklahoma is shown getting The purpose of this report is to describe and document steadily worse from November through March, improving the Water Year 2006 hydrologic drought in Oklahoma and with some spring and summer rains from April through the compare it to four previous major hydrologic droughts, water beginning of July and then the drought is worst in August. years 1929–41, 1952–56, 1961–72, and 1976–81. Conditions improved in September and October. A brief introduction includes (1) a definition of drought sequence, (2) a presentation of monthly nationwide drought Statewide Precipitation and Streamflow monitor graphics for Water Year 2006, and (3) a comparison of annual statewide total precipitation and statewide streamflow Precipitation and runoff plots help to characterize the runoff from water years 1925–2006 in Oklahoma with the four duration and severity of hydrologic drought by comparing previous major hydrologic droughts in the 20th century high- annual statewide precipitation and runoff departures from lighted. Annual area-averaged precipitation totals for Water long-term median values. Annual departures are shown as Year 2006 for the nine National Weather Service Climate positive bars when annual departures exceed the long-term Divisions in Oklahoma are compared to precipitation during median and as negative bars when annual departures are four previous major hydrologic droughts in the 20th century less than the long-term median. Thus departures that are to show how rainfall deficits varied by region. Next the mean consistently negative over several years provide a measure annual streamflow during Water Year 2006 at 12 long-term of drought duration or persistence, while the magnitude of streamflow-gaging sites are compared to streamflow during individual departures provides a measure of severity. Negative four previous major hydrologic droughts in the 20th century departure of runoff also can be characterized as runoff deficits. to show how streamflow deficits varied by region. The effects The period of water years 1925–2006 was selected as of low streamflows are discussed to include (1) conservation the period of record for long-term drought analysis. Few storage at major reservoirs throughout the state, (2) hydroelec- continuous record streamflow-gaging sites existed and there tric power generation, (3) ground-water levels at a long-term were record year gaps where no streamflow-gaging sites were site, and (4) wildfires. operated before 1925 (U.S. Geological Survey, 2007a). The The effects of the hydrologic drought of Water Year 2006 four previous major hydrologic drought periods, water years on agriculture are beyond the scope of this report and a discus- 1929–41, 1952–56, 1961–72, and 1976–81 were identified sion can be found in Oklahoma Agricultural Statistics 2007 from the statewide runoff plot and modified from a previous (National Agricultural Statistics Service, 2007). drought report by Tortorelli and others (1991). The 2002–2006 hydrologic drought period was identified from the statewide Progression of Drought runoff plot. Figures 3 and 4 show how annual statewide precipitation Definition of Drought Sequence and annual statewide median runoff compare during water years 1925–2006. First, the statewide annual mean precipita- The drought sequence development is illustrated in figure tion for each water year of the period (National Climatic Data 1. The start of a drought begins with precipitation deficiency, Center, 2007a) is plotted as the departure from the median high temperatures and winds, and low humidity, collectively annual precipitation for the period (“normal” annual precipita- resulting in “meteorological” drought. As soil moisture is tion, blue line), and a 5-year weighted-average departure pre- reduced and plants are stressed, “agricultural” drought is expe- cipitation is plotted as a red line (fig. 3). The selected drought rienced. If the drought continues for several seasons, stream- periods are indicated by different colored annual bars. Water flow is reduced to critical levels and “hydrologic” drought Year 2006 was second driest in the 82 years of record from results (Oklahoma Water Resources Board, 2007a; National 1925–2006. Drought Mitigation Center, 2006a). Second, the statewide annual median runoff for each water year of the period (U.S. Geological Survey, 2007a) is plotted as the departure from the median annual runoff for Drought Monitor the period (“normal” annual runoff, blue line), and a 5-year The U.S. Drought Monitor is a graphic depiction of weighted-average departure runoff is plotted as a red line broad-scale drought in the United States displayed on the (fig. 4). The selected drought periods are indicated by different National Drought Mitigation Center web page (National colored annual bars. Based on runoff, Water Year 2006 was Drought Mitigation Center, 2007). Agricultural and hydrologic sixth driest in the 82 years of record from 1925–2006. drought effects are displayed on a weekly graphic accompa- Wetter years plot above the median line and drier years nied by tabular data and general regional narratives for that plot below the median line. Water Year 2006 then can be com- week. pared to the dry years in the four previous major hydrologic Figure 2 shows the progression of the Water Year 2006 droughts by depth of the bars. The length and severity of the drought with 12 monthly Drought Monitor graphs from water year 2002–2006 drought period also can be compared Introduction 3

~ I i rrecipitation deficiency nigh Temperature/Winds (Amounl.lntensity, Timing) Low Uumidity Greater Sunshine Reduced Runoff Less Cloud Cover Reduced Infiltration/rercolation Increased Evaporationl Reduced Groundwater Recharge Transpiration

Soil Water Deficiency ~;-rT"~~". '~~''~:"':L-4",,'

Reduced Streamflow Reduced Inflow to Reservoirs/Lakes/ponds Reduced Wetlands lit Wildlife nabitat

Economic Social [nvironmental [ffeels [ffects [ffects

Figure 1. Sequence of drought development (Oklahoma Water Resources Board, 2007a; modified from National Drought Mitigation Center, 2006a) 4 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

U.S. Drought Monitor

November 1, 2005 December 6, 200S V_' ...... UT

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February 7, 2006 H~?Erni7

Re/nsed ThufSdllY, Jlfnullry 12, 2006 RCieased Tllurs~y. FelJru~ry 9, 2006 JI_ ~t.e...... CPCINl:IAA A,,~ Rich r..'l..... t:P'CiHC£Pi~OAA

March 7.2006 Apri14,2006 ~~~ V_1o ... f6t

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~. EXPLANATION """"00_1D!y ,... oew-. aDmonanl "'PK/I 01 CrOUljlll_ "'_Me ... ~ "II'K.UItu<. (CItIp .,..un • D2 Co...... _~ 0'.._.) H·I1~~ • 03 0r0ugr!I- E~ • Dol Orougnl. ~ r"DnK

u.s. Drought Monitor May 2, 2006 June 6, 2006 _...... "" v_•..-....

RclNSM Thursd.Jy, Mol)' 4, 2006 RelN~ ThursfUy, June S, 700f A ..""",· if.... ,--..__1lmo""'1I1~e-...... - ..... I"WM. _""""",,.~C_

July 4, 2006 V_I&A,lOf

MH5M Thursday. July S. 200fS Rwund ThWlRy, Augus' 10. lOOll .--, Dooo,.t.t-_ r_",,_.--.CJ'OfIJOoU """'-'- ,...... ~~e-,MMA

September"_.__ IDr5. 2006

R~usMlThursrhy, S,ptemw 7, zooe R'~sed Thuf$d,ly, October '. 2006 A ..mor. fit.., ,"""Ill, N._ Ofo<.'ll~'.~eM,., "u_, Roell r...., C'--Pfedtc_CMHt. NOAA EXPLANATION ,,--., ~ DlDru.qoo._ -• ~ tlruulr" -s-. • Dlllfo4'ol. t.s .ll'l~,,-

,INt 0t0IIl/III AWwoI_~ O'IlttOIo1_-.oM LOCIlI-''''''''OOI)' Figure 2. Monthly Drought Monitor Graphs, November 1, 2005, through October 3, 2006, (National Drought Mitigation Center, 2007). 6 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

,noitatipicerPlaun 28

24 Oklahoma Statewide Precipitation 1925-2006 Annual Departure 20 Long-Term Median Annual Precipitation 33.51 inches 5-year Weighted Average 16

r 12

ey A 8

p de 4

eh M 0

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-12 Hydrologic -16 au Droughts: 1929-41 1952-56 1961-72 1976-81 2002-06

nA -20 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year Figure 3. Oklahoma statewide precipitation showing the annual departure from the long-term statewide median of 33.51 inches (blue line) and a 5-year weighted average line for water years 1925–2006 (red line). Wetter years plot above the median line and drier years plot below the median line.

,ffonuRlaunnA 10 Oklahoma Statewide Runoff 8 1925-2006

6 Annual Departure ra Long-Term Median Annual Runoff 3 inches

y 5-year Weighted Average

e e 4

c f 2

trapeDlaun 0

-2 Hydrologic

nA Droughts: 1929-41 1952-56 1961-72 1976-81 2002-06 -4 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year Figure 4. Oklahoma statewide runoff showing the annual departure from the long-term statewide median of 3 inches (blue line) and a 5-year weighted average line for water years 1925–2006 (red line). Wetter years plot above the median line and drier years plot below the median line. Precipitation By Climate Division 7 to the four previous major hydrologic drought periods by the Deke Arndt of Oklahoma Climatological Survey supplied 5-year weighted average line. Water Year 2006 precipitation maps and Brian Vance of The hydrologic drought of water years 1929–41 was the Oklahoma Water Resources Board provided a modified known as the “Dust Bowl” years in the Great Plains and is Drought Sequence diagram from the National Drought Mitiga- documented in several references (Hoyt, 1936 and 1938; Nace tion Center. Additional special thanks go to Daniel Fenner of and Pluhowski, 1965; Egan, 2006; National Drought Mitiga- the U.S. Fish and Wildlife Service for providing photographs tion Center, 2006b). This drought was particularly severe in of low flow in August 2006 at numerous sites along the reach western Oklahoma with a deficit runoff in 1934; whereas, of the Canadian River above Calvin. Rachel Esralew of the major wind erosion happened over the entire state in 1936 Oklahoma Water Science Center compiled site maps. USGS (Nace and Pluhowski, 1965). The 1929–41 drought triggered personnel provided low flow photographs in August 2006 at nationwide soil conservation measures (National Drought USGS streamflow gages. The Oklahoma Publishing Company Mitigation Center, 2006b). provided the photograph of Thunderbird Lake shoreline on the The hydrologic drought of water years 1952–56 was the back cover. most widespread and the most severe for all regions of Okla- homa for precipitation and in most regions for runoff than the other hydrologic drought periods (Nace and Pluhowski, 1965; Tortorelli and others, 1991; figs. 3–4). This drought prompted Precipitation By Climate Division the construction of Atoka Lake to provide a reliable water sup- Oklahoma has nine National Weather Service Climate ply for Oklahoma City (Johnson, 1956) and prompted many Divisions (fig. 7) for which monthly area-averaged precipita- Oklahoma communities to plan for long-term water supply. tion data are available (National Climatic Data Center, 2007b). The hydrologic drought of water years 1961–72 also was These data were totaled for each water year from 1925–2006. widespread and lasted longer than that in 1952–56 but gener- These totals give a sense of annual precipitation in Oklahoma ally was not as severe (Tortorelli and others, 1991; figs. 3-4). on a regional basis. By this time many of the major reservoirs in Oklahoma were Table 1 shows how Water Year 2006 precipitation com- completed (Vance, 2007). pares with that during the driest year from each of the four The hydrologic drought of water years 1976–81 also was previous major hydrologic droughts within each of the nine widespread, but was not as severe or persistent as the previous National Weather Service Climate Divisions to show how three major droughts (Tortorelli and others, 1991; figs. 3-4). rainfall deficits in Oklahoma varied by region. Table 1 also The precipitation and runoff plots in figures 3 and 4 shows how the annual precipitation for the selected years com- indicate that Water Year 2006 was very dry (second lowest pares with the long-term median annual precipitation values statewide precipitation in the 1925–2006 study period) with for water years 1925–2006 (“normal”) and the ranking (lowest very low statewide runoff (sixth lowest in the 1925–2006 ranking associated with driest year). Precipitation in water study period). On that basis, drought conditions in Water Year year 2006 was slightly less than the long-term climate division 2006 were severe, but drought duration or persistence cannot median in two of the nine climate divisions, Climate Division yet be characterized (October 2006). 1 Panhandle and Climate Division 4 West Central (minor rain- Regional streamflow patterns for Water Year 2006 fall deficits of 85 percent or more of normal precipitation). In (fig. 5) indicate that Oklahoma was part of the regionwide all other climate divisions, Water Year 2006 precipitation was below-normal streamflow for the Arkansas-White-Red River substantially less then the long-term climate division medians, Basin, the sixth driest since 1930 (U.S. Geological Survey, with severe rainfall deficits ranging from only 65 to 73 percent 2008a). Figure 6 shows the percentage of 82 long-term stream- of normal annual precipitation. Table 1 also shows that state- flow stations in Oklahoma (at least 30 years of record) having wide precipitation Water Year 2006 was second driest in the below normal streamflow during the water year 2002–2006 82 years of record from 1925–2006 and was only 72 percent drought period (U.S. Geological Survey, 2008b). As indicated of the normal precipitation. Only one year in the 1925–2006 by the dashed line in figure 6, about 25 percent of all stations period was drier, Water Year 1956 with only 56 percent of can be expected to have streamflow below normal at any given normal precipitation. time, where normal streamflow is considered to be within the The Oklahoma Mesonet, a statewide network of environ- 25th and 75th percentile at each site. Figure 6 shows that for some days in August and November 2006, the percentage of ment monitoring stations, consists of 115 automated stations long-term stations having below-normal streamflow reached covering Oklahoma and provides 5-minute precipitation 80 to 85 percent. data. At least one station is located in each of 77 Oklahoma counties. Oklahoma Mesonet climate data are available since 1994, but were not used for this report so that data from one Acknowledgments source (National Climatic Data Center, 2007b) for the period 1925–2006 would be used. In addition, Mesonet data uses The author thanks many people for their contributions to mean annual precipitation from calendar years 1971–2000 the data collection and data analysis presented in this report. as “normal” instead of median annual precipitation from 8 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Reginmll Patt~rns

TIle niled Siales (including Pucno Rico) is divided illlo 21 Inrge dmln ages. or wllter resources leglous. rhes.e hydrologIc nrens nre bnsed on surfllce lopogmphy and coulllin either Ihe drainage area ofa major liver. such l'l~ the CollUubin. Ihe combined draillage areas ofa series ofriwfs. such a~ rhe Texlls-Gulf re~joll which incllldes II number of rivers draining inlo the Gulf of Mex ico. or [he aWl ofan island or island eroup. Water resources re2ions prOVide a eollerellt. waTershed·based framework tor depicTing stretuufiow vurialion~.

In 2006. noTable' rC2ionsl Slrcmn flow chtTerel1ces were obselve<1 nl0l12 The Ensl Coast TIle New Engfilild region. for example. recorded its highest aHmlal flow since 1930. reflectiug the record high pl'e~ipi"l.liollihal fell 011 this nrea dUring the yenr. The South Allantic Gulftegioll. III contrasT. W;'lS below nomlnL Below-llonllnl conditions also were preV:1lenl for PR-VI most the Greal Plaiu1> regions find Alaska.

CiS' ··0111 of 63 yeOlr~ ofhi~loric;'l1 dOlTOl. ..HI.~~ Explanation - Rank I , 59-70 20·58 .I~I Below Normal Above b9low'" normal normal rmal

Figure 5. Regional streamflow patterns Water Year 2006 (U.S. Geological Survey, 2008a). Precipitation By Climate Division 9

Since January 16, 2001 Oklahoma [82 sites] 100 90 80 70 60 50 40 30 20 Expected percentage 10 0 Percent of Stations Below Normal Streamflow 2001 2002 2003 2004 2005 2006 2007 Year

EXPLANATION

The Percent of Stations Below Normal Streamflow, plotted as the red line on the above graph, is calculated each day as the percent of streamflow gages having below normal flow, where the lower bound for normal is the 25th percentile value (dotted line) among all historical values for all days of the year. The percent of stations below normal is based only on streamflow gages in the state having at least 30 years of record

Figure 6. Percentage of stations below normal streamflow since January 16, 2001, through February 1, 2008, in Oklahoma (U.S. Geological Survey, 2007c). 10 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Table 1. Summary of precipitation at Climate Divisions in Oklahoma comparing the median of mean annual precipitation during water years 1925-2006 (measure of “normal” precipitation) with average annual precipitation during periods of previous documented hydrologic droughts and the recent hydrologic drought period.

[avg, average; %, percent; Rank, rank of driest year of drought period out of period WY 1925-2006; WY, water year; SW, statewide]

Hydrologic Drought Periods 1929-41 3 1952-56 3 Lowest year / Rank Lowest year / Rank Long-term WY avg WY Avg Climate annual annual Percent long- annual Percent long- Division Climate Division name median precipitation term median precipitation term median number (inches) (inches) (inches)

SW Statewide 1 33.51 1936 5 1956 1 25.24 75% 18.68 56%

1 Panhandle 2 19.54 1937 2 1956 1 12.24 63% 11.34 58%

2 North Central 2 28.94 1936 6 1956 1 20.16 70% 15.10 52%

3 Northeast 2 38.96 1939 8 1956 1 30.59 79% 22.90 59%

4 West Central 2 26.55 1940 8 1952 1 20.14 76% 15.98 60%

5 Central 2 33.73 1936 2 1956 1 24.03 71% 19.74 59%

6 East Central 2 42.91 1936 3 1956 1 28.11 66% 23.86 56%

7 Southwest 2 27.56 1939 4 1956 1 18.75 68% 17.45 63%

8 South Central 2 36.63 1939 2 1956 1 24.19 66% 16.46 45%

9 Southeast 2 48.51 1934 2 1956 1 30.86 64% 25.10 52%

1 Ranks from Statewide Monthly Precipitation Totals, National Climatic Data Center (2007a) 2 Ranks from Climate Division Monthly Precipitation Totals, National Climatic Data Center (2007b). 3 Documented drought periods are modified from Tortorelli and others, 1991. Precipitation By Climate Division 11

[avg, average; %, percent; Rank, rank of driest year of drought period out of period WY 1925-2006; WY, water year; SW, statewide]

Hydrologic Drought Periods 1961-72 3 1976-1981 3 2002-2006 2006 Lowest Year / Rank Lowest Year / Rank Lowest Year / Rank Rank WY avg WY avg WY avg WY avg Climate Percent Percent Percent Percent annual annual annual annual Division long-term long-term long-term long-term precipitation precipitation precipitation precipitation number median median median median (inches) (inches) (inches) (inches)

SW 1963 3 1978 10 2006 2 2 24.60 73% 27.11 81% 24.12 72% 24.12 72%

1 1970 4 1976 29 2002 15 22 13.05 67% 17.58 90% 15.34 79% 16.69 85%

2 1966 5 1976 14 2006 7 7 20.15 70% 23.24 80% 20.23 70% 20.23 70%

3 1963 2 1981 14 2006 5 5 24.81 64% 32.89 84% 28.29 73% 28.29 73%

4 1970 3 1976 24 2002 19 28 18.00 68% 22.23 84% 21.90 82% 23.46 88%

5 1972 6 1976 7 2006 3 3 25.08 74% 25.41 75% 24.17 72% 24.17 72%

6 1963 4 1980 6 2006 2 2 28.24 66% 30.30 71% 27.70 65% 27.70 65%

7 1967 2 1980 23 2006 3 3 17.46 63% 23.40 85% 18.59 67% 18.59 67%

8 1963 4 1978 8 2006 3 3 25.15 69% 27.78 76% 24.45 67% 24.45 67%

9 1963 7 1978 3 2006 6 6 35.02 72% 31.95 66% 34.89 72% 34.89 72% 12 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

1 PANHANDLE 2 3 NORTH CENTRAL NORTHEAST

5 Climate Division number OKLAHOMA CENTRAL 4 and name WEST 6 CENTRAL 5 EAST CENTRAL CENTRAL 7 SOUTHWEST 8 9 SOUTH SOUTH- CENTRAL EAST 050 100 200 MILES

0 200100KILOMETERS

Albers Equal Area Conic Projection

Figure 7. National Weather Service Climate Divisions in Oklahoma. water years 1925–2006. This period contains an extremely from the 1952–56 drought period, with only 15.10 inches wet period (fig. 3); therefore, data presented on the Mesonet of rainfall, a deficit of 13.84 inches or 52 percent of normal website (fig. 8; Oklahoma Climatological Survey, 2008a, annual area precipitation. 2008b) indicated more severe precipitation deficits in 2006 than in table 1. However, these data do show how Water Year 2006 differs from normal and give a sense of regional rainfall Climate Division 3 Northeast deficits. Climate Division 3 Northeast is in northeast Oklahoma. Water Year 2006 was the fifth driest in the 82 years of record Climate Division 1 Panhandle from 1925–2006, with 28.29 inches of rainfall, a deficit of 10.67 inches or 73 percent of normal area precipitation Climate Division 1 Panhandle is in far northwest Okla- (table 1). Water Year 1956 was the driest year, from the homa. Water Year 2006 was the 22nd driest in the 82 years of 1952–56 drought period, with only 22.90 inches of rainfall, record from 1925–2006, with 16.69 inches of rainfall, a deficit a deficit of 16.06 inches or 59 percent of normal annual area of 2.85 inches or 85 percent of normal area precipitation (table precipitation. 1). Water Year 1956 was the driest year, from the 1952–56 drought period, with only 11.34 inches of rainfall, a deficit of 8.20 inches or 58 percent of normal annual area precipitation. Climate Division 4 West Central Climate Division 4 West Central is in west-central Okla- Climate Division 2 North Central homa. Water Year 2006 was the 28th driest in the 82 years of record from 1925–2006, with 23.46 inches of rainfall, a deficit Climate Division 2 North Central is in north-central of 3.09 inches or 88 percent of normal area precipitation Oklahoma. Water Year 2006 was the seventh driest in the (table 1). Water Year 1952 was the driest year, from the 82 years of record from 1925–2006, with 20.23 inches of 1952–56 drought period, with only 15.98 inches of rainfall, rainfall, a deficit of 8.71 inches or 70 percent of normal area a deficit of 10.57 inches or 60 percent of normal annual area precipitation (table 1). Water Year 1956 was the driest year, precipitation. Precipitation By Climate Division 13

, , ~ ~ G m m u ~ ~ ~ • ~ percenl

Percent of Normal Rainfall Water Year 2006 October 1, 2005, ~hrough September 30,2006 •

, • -20.15·10 6 D 51115 '" > i'lches

Departure from Normal Rainfall Water Year 2006 October 1,2005, through September 30,2006 .. " Figure 8. Oklahoma (A) percent of normal rainfall, Water Year 2006 (Oklahoma Climatological Survey, 2008a) (B) departure from normal rainfall, Water Year 2006 (Oklahoma Climatological Survey, 2008b). 14 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Climate Division 5 Central Streamflow of Long-Term Sites

Climate Division 5 Central is in central Oklahoma. Water Twelve long-term streamflow-gaging sites with periods Year 2006 was the third driest in the 82 years of record from of record ranging from 62 to 78 years were selected to show 1925–2006, with 24.17 inches of rainfall, a deficit of how streamflow deficits varied by region (fig. 9, table 2). Two 9.56 inches or 72 percent of normal area precipitation graphs are presented for each long-term site (figs. 10 to 21). (table 1). Water Year 1956 was the driest year, from the The first graph is similar to the statewide runoff plot in figure 1952–56 drought period, with only 19.74 inches of rainfall, 4. The annual mean streamflow (U.S. Geological Survey, a deficit of 13.99 inches or 59 percent of normal annual area 2007b) for each water year of the period of record is plotted as precipitation. a departure bar from the long-term median annual flow (“normal” annual flow, blue line), and a 5-year weighted-average Climate Division 6 East Central departure streamflow is plotted as a red line (A graphs). Wetter years plot above the median line and drier years plot below Climate Division 6 East Central is in east-central Okla- the median line. Water Year 2006 then can be compared to the homa. Water Year 2006 was the second driest in the 82 years dry years from the four previous major hydrologic droughts in of record from 1925–2006, with 27.70 inches of rainfall, a the 20th century by the depth of bars. The length and sever- deficit of 15.21 inches or 65 percent of normal area precipita- ity of the water year 2002–2006 drought period in terms of tion (table 1). Water Year 1956 was the driest year, from the streamflow deficit can be compared to the four previous major 1952–56 drought period, with only 23.86 inches of rainfall, hydrologic droughts by the 5-year weighted average line. a deficit of 19.05 inches or 56 percent of normal annual area The second graph shows a comparison of the daily-mean precipitation. flow from Water Year 2006 (red line; U.S. Geological Survey, 2008d) to the long-term daily mean flow (blue line; U.S. Geo- logical Survey, 2008e) and provides an indication of how the Climate Division 7 Southwest streamflow deficits changed seasonally (B graphs). Table 2 shows how Water Year 2006 streamflow from Climate Division 7 Southwest is in southwest Oklahoma. each long-term site compares with the driest year from each Water Year 2006 was the third driest in the 82 years of record of the four previous major hydrologic droughts in the 20th from 1925–2006, with 18.59 inches of rainfall, a deficit of century, and shows the rank and percent of long-term median- 8.97 inches or 67 percent of normal area precipitation annual flow (“normal”) for each low-flow year. Statewide (table 1). Water Year 1956 was the driest year, from the runoff during the driest years also is ranked. Statewide runoff 1952–56 drought period, with only 17.45 inches of rainfall, in Water Year 2006 was sixth driest in the 82 years of record a deficit of 10.11 inches or 63 percent of normal annual area from 1925-2006. precipitation. Salt Fork Arkansas River at Tonkawa Climate Division 8 South Central Salt Fork Arkansas River at Tonkawa (07151000) is a Climate Division 8 South Central is in south-central streamflow-gaging site in north-central Oklahoma. Water Oklahoma. Water Year 2006 was the third driest in the Year 2006 was the sixth driest in the 65 years of record from 82 years of record from 1925–2006, with 24.45 inches of 1942–2006, with just 19 percent of normal annual flow rainfall, a deficit of 12.18 inches or 67 percent of normal area (table 2). Water Year 1954 was the driest year, from the precipitation (table 1). Water Year 1956 was the driest year, 1952–56 drought period, with 12 percent of normal annual from the 1952–56 drought period, with only 16.46 inches flow. Zero flow was not recorded during Water Year 2006, of rainfall, a deficit of 20.17 inches or 45 percent of normal with some wet periods in November, May, and June (fig. 10). annual area precipitation. The lowest flow was at the end of the water year in August and September (fig. 10; appendix 1; U.S. Geological Survey, Climate Division 9 Southeast 2008c).

Climate Division 9 Southeast is in southeast Oklahoma. Chikaskia River near Blackwell Water Year 2006 was the sixth driest in the 82 years of record from 1925–2006, with 34.89 inches of rainfall, a deficit of Chikaskia River near Blackwell (07152000) is a stream- 13.62 inches or 72 percent of normal area precipitation flow-gaging site in north-central Oklahoma. Water Year 2006 (table 1). Water Year 1956 was the driest year, from the was the 15th driest in the 70 years of record from 1937–2006, 1952–56 drought period, with only 25.10 inches of rainfall, with 45 percent of normal annual flow (table 2). Water Year a deficit of 23.41 inches or 52 percent of normal annual area 1954 was the driest year, from the 1952–56 drought period, precipitation. Streamflow of Long-Term Sites 15

38° 36° 34°

ARKANSAS 94° MISSOURI Illinois River near Tahlequah # Red River at Arthur City, Texas # at Calvin 96° 96° Canadian River # # River # near Blue Blue River F

Arkansas near Ripley Cimarron River # E # River near Wetumka Red River near Gainesville, Texas # North Canadian River # #

Canadian D near Dickson Washita River

River at Tonkawa River C Salt Fork Arkansas 98°

near Blackwell River Chikaskia River 98° B Cimmaron

Washita TEXAS A

River near Waynoka # Cimarron River River KANSAS

Red

Canadian Salt Fork Red River at Mangum #

North 100° 100° Miles 100 Kilometers 100 50 EXPLANATION A. near Thomas B. at Bridgeport C. near Union City D. at Purcell E. near Wanette F. near Ada Canadian River: 102° 50 County Boundary Long-term streamflow-gaging stations Station names correspond to table 2 Appendix 5 photograph locations State Boundary Line Rivers 25 25 102° # Rivers from U.S. Environmental Protection Agency River Reach File versionAlbers 1. Equal-Area Projection. North American Datum 1983.

0 0 COLORADO MEXICO NEW 36° 34° Figure 9. Selected long-term streamflow-gaging stations in Oklahoma and Canadian River photograph locations. 16 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Table 2. Summary of streamflow conditions at selected long-term streamflow-gaging stations in Oklahoma comparing the median of mean annual streamflow (measure of “normal” streamflow) with average annual streamflow during periods of previous documented hydrologic droughts and the recent hydrologic drought period.

[yr, year; avg, average; Rank, rank of driest year of drought period out of period of record; mi2, square miles; N, nonregulated; R, regulated; WY, water year; ft3/s, cubic feet per second; SW, statewide]

Contributing Long-term Type of Continuous record Years Site Station drainage annual Station name record period of record of no. number area median (N/R) (complete WY) record (mi2) (ft3/s)

SW Statewide 1 1925-2006 1 82

1 07151000 Salt Fork Arkansas River at Tonkawa, Okla. 4,520 R 1942-2006 65 808

2 07152000 Chikaskia River near Blackwell, Okla. 1,859 N 1937-2006 70 480

3 07158000 Cimarron River near Waynoka, Okla. 8,504 N 1938-2006 69 231

4 07161450 Cimarron River near Ripley, Okla. 2 13,053 N 1940-2006 67 1,345

5 07196500 Illinois River near Tahlequah, Okla. 959 N 1936-2006 71 919

6 07231500 Canadian River at Calvin, Okla. 23,151 N,R 1939-42, 1945-2006 66 1,376

7 07242000 North Canadian River near Wetumka, Okla. 9,391 R 1938-2006 69 683

8 07300500 Salt Fork Red River at Mangum, Okla. 1,357 N 1938-2006 69 71.8

9 07316000 Red River near Gainesville, Texas 24,846 N,R 1937-2006 70 2,535

10 07331000 Washita River near Dickson, Okla. 7,202 N,R 1929-2006 78 1,400

11 07332500 Blue River near Blue, Okla. 476 N 1937-2006 70 254

12 07335500 Red River at Arthur City, Texas 38,595 R 1945-2006 62 7,223

1 Ranks from Statewide Annual Runoff Summary USGS Waterwatch web page, U.S. Geological Survey (2007a) Although there is record from continuous streamflow gages since WY 1903, there were few operating gages and gaps where no gages were operating prior to 1925. 2 Includes streamflow record 1940-87 from nearby station 07161000, Cimarron River at Perkins, Okla. 3 Documented drought periods are modified from Tortorelli and others, 1991. 4 Station records do not span entire drought period Streamflow of Long-Term Sites 17

Hydrologic Drought Periods 1929-41 3 1952-56 3 1961-72 3 1976-1981 3 2002-2006 2006 Lowest yr / Rank Lowest yr / Rank Lowest yr / Rank Lowest yr / Rank Lowest yr / Rank Rank Avg Percent Avg Percent Avg Percent Avg Percent Avg Percent Avg Percent Site annual long- annual long- annual long- annual long- annual long- annual long- no. flow term flow term flow term flow term flow term flow term (ft3/s) median (ft3/s) median (ft3/s) median (ft3/s) median (ft3/s) median (ft3/s) median

SW 1940 1 1953 2 1964 4 1981 7 2006 6 6

1 NA 1954 1 1964 3 1981 13 2006 6 6 95.5 12% 137 17% 280 35% 157 19% 157 19%

2 1940 4 2 1954 1 1966 4 1981 7 2006 15 15 76.6 16% 71.0 15% 97.6 20% 152 32% 217 45% 217 45%

3 1939 4 26 1956 5 1971 4 1977 17 2002 3 10 174 75% 53.6 23% 46.7 20% 134 58% 46.0 20% 96.1 42%

4 1940 4 4 1953 1 1971 2 1981 11 2006 12 12 307 23% 235 17% 294 22% 455 34% 491 37% 491 37%

5 1940 4 6 1954 1 1964 3 1981 5 2006 8 8 279 30% 193 21% 239 26% 275 30% 289 31% 289 31%

6 1940 4 8 1956 6 1966 3 1981 1 2006 2 2 478 35% 393 29% 217 16% 184 13% 190 14% 190 14%

7 1940 4 2 1956 1 1963 3 1981 5 2006 4 4 157 23% 156 23% 166 24% 178 26% 176 26% 176 26%

8 1940 4 1 1952 4 1971 2 1981 5 2006 3 3 12.3 17% 17.5 24% 12.5 17% 22.7 32% 14.4 20% 14.4 20%

9 1939 4 5 1953 2 1964 3 1983 12 2006 1 1 1,010 40% 651 26% 654 26% 1,274 50% 567 22% 567 22%

10 1939 4 3 1956 5 1964 1 1981 7 2006 2 2 391 28% 441 31% 340 24% 495 35% 384 27% 384 27%

11 1939 4 2 1956 1 1964 9 1980 4 2006 5 5 42.9 17% 30.8 12% 114 45% 77.7 31% 79.5 31% 79.5 31%

12 NA 1952 9 1964 2 1980 3 2006 1 1 4,182 58% 2,754 38% 2,953 41% 1,794 25% 1,794 25% 18 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Hydrologic Droughts 1952-56 1961-72 1976-81 2002-06 4,000 Salt Fork Arkansas River at Tonkawa, Okla. 3,500 07151000 Regulated 1942-2006 3,000

3 2,500 Annual Departure Median Annual Streamflow 808 ft3 /s 2,000 5-year - Weighted Average

1,500

1,000

500

in cubic feet per second (ft /s) 0

-500 A

Annual Departure from Median Annual Streamflow, -1,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Salt Fork Arkansas River at Tonkawa, Okla. 07151000 40,000 30,000 3 Daily-Mean Sreamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1942-2006 Regulated 1942-2006 10,000 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40 Streamflow, in cubic feet per second (ft /s) 30 B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Figure 10. Salt Fork Arkansas River at Tonkawa (A) annual departure from long-term median annual streamflow, water years 1942–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1942–2006. Streamflow of Long-Term Sites 19

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

2,000 Chikaskia River near Blackwell, Okla. 07152000 Unregulated 1937-2006 1,500 Annual Departure 3 3 Median Annual Streamflow 480 ft /s 5-year Weighted Average 1,000

500

0 in cubic feet per second (ft /s) -500 A

Annual Departure from Median Annual Streamflow, -1,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Chikaskia River near Blackwell, Okla. 07152000 40,000 30,000

3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1937-2006 10,000 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40

Streamflow, in cubic feet per second (ft /s) 30 B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 11. Chikaskia River near Blackwell (A) annual departure from long-term median annual streamflow, water years 1937–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1937–2006. 20 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

1,000 Cimarron River near Waynoka, Okla.

750 07158000 Unregulated 1938-2006

3 Annual Departure Median Annual Streamflow 231 ft3 /s 500 5-year Weighted Average

250

in cubic feet per second (ft /s) -250 A

Annual Departure from Median Annual Streamflow, -500 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Cimarron River near Waynoka, Okla. 07158000 40,000 30,000

3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1938-2006 10,000 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 Zero 40 flow 30 Streamflow, in cubic feet per second (ft /s) B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 12. Cimarron River near Waynoka (A) annual departure from long-term median annual streamflow, water years 1938–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1938–2006. Streamflow of Long-Term Sites 21

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

6,000 Cimarron River near Ripley, Okla. 5,000 07161450 Unregulated 1940-2006

3 4,000 Annual Departure Median Annual Streamflow 1,345 ft3 /s 3,000 5-year Weighted Average

2,000

1,000

in cubic feet per second (ft /s)

-1,000 A

Annual Departure from Median Annual Streamflow, -2,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Cimarron River near Ripley, Okla. 07161450 40,000 30,000 3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1940-2006 10,000 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40 Streamflow, in cubic feet per second (ft /s) 30 B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 13. Cimarron River near Ripley (A) annual departure from long-term median annual streamflow, water years 1940–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1940–2006. Includes streamflow record 1940–87 from nearby station 0716100, Cimarron River at Perkins. 22 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

2,000

Illinois River near Tahlequah, Okla. Annual Departure 3 1,500 07196500 Unregulated 1936-2006 Median Annual Streamflow 919 ft /s 5-year Weighted Average

1,000

500

in cubic feet per second (ft /s) -500 A

Annual Departure from Median Annual Streamflow, -1,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Illinois River near Tahlequah, Okla. 07196500 40,000 30,000

3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1936-2006 10,000 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40

Streamflow, in cubic feet per second (ft /s) 30 B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 14. Illinois River near Tahlequah (A) annual departure from long-term median annual streamflow, water years 1936–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1936–2006. Streamflow of Long-Term Sites 23

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06 5,000 Canadian River at Calvin, Okla. 4,000 07231500 Unregulated 1939-64 Regulated 1965-2006

3 Annual Departure 3,000 Median Annual Streamflow 1,376 ft3 /s 5-year Weighted Average 2,000

1,000

0 in cubic feet per second (ft /s) -1,000 A

Annual Departure from Median Annual Streamflow, -2,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Canadian River at Calvin, Okla. 07231500 40,000 30,000 3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1939-42, 1945-2006 10,000 Regulated 1965-2006 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40 Zero Streamflow, in cubic feet per second (ft /s) 30 B flow 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 15. Canadian River at Calvin (A) annual departure from long-term median annual streamflow, water years 1939–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1939–2006. 24 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

2,000 North Canadian River near Wetumka, Okla. 07242000 Regulated 1938-2006 1,500 Annual Departure 3 Median Annual Streamflow 683 ft3 /s 5-year Weighted Average 1,000

500

0 in cubic feet per second (ft /s) -500 A

Annual Departure from Median Annual Streamflow, -1,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 North Canadian River near Wetumka, Okla. 07242000 40,000 30,000 3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1938-2006 10,000 Regulated 1938-2006 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40 Streamflow, in cubic feet per second (ft /s) 30 B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 16. North Canadian River near Wetumka (A) annual departure from long-term median annual streamflow, water years 1938–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1938–2006. Streamflow of Long-Term Sites 25

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

250 Salt Fork Red River at Mangum, Okla. 200 07300500 Unregulated 1938-2006 Annual Departure 3 3 150 Median Annual Streamflow 71.8 ft /s 5-year Weighted Average

100

in cubic feet per second (ft /s) -50 A

-100

Annual Departure from Median Annual Streamflow, 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

10,000 7,000 5,000 Salt Fork Red River at Mangum, Okla. 07300500 4,000 3,000 3 Daily-Mean Streamflow Water Year 2006 2,000 Long-Term Daily-Mean Streamflow Water Years 1938-2006 1,000 700 500 400 300 200

100 70 50 40 30 20

10 7 5 4 Zero

Streamflow, in cubic feet per second (ft /s) 3 B flow 2

1 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 17. Salt Fork Red River at Mangum (A) annual departure from long-term median annual streamflow, water years 1938–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1938–2006. 26 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06 10,000 Red River near Gainesville, Texas 07316000 Unregulated 1937-1944 8,000 Regulated 1945-2006

/s) Annual Departure 3 3 6,000 Median Annual Streamflow 2,535 ft /s 5-year Weighted Average

4,000

2,000

0 in cubic feet per second (ft -2,000 A

Annual Departure from Median Annual Streamflow Annual Departure from Median -4,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Red River near Gainesville, Texas 07316000 40,000 30,000 Daily-Mean Streamflow Water Year 2006 20,000 /s)

3 Long-Term Daily-Mean Streamflow Water Years 1937-2006 10,000 Regulated 1945-2006 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40 Streamflow, in cubic feet per second (ft Streamflow, 30 20 B

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 18. Red River near Gainesville, Texas, (A) annual departure from long-term median annual streamflow, water years 1937–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1937–2006. Streamflow of Long-Term Sites 27 with 15 percent of normal annual flow. Zero flow was not month of August with some wet periods in October and March recorded during Water Year 2006, with some wet periods in through June (fig. 15). The lowest flow was at the end of the November, April-May, and August-September (fig. 11). The water year in August and September (fig. 15; U.S. Geological lowest flow was near the end of the water year in July (fig. 11; Survey, 2008c). appendix 2; U.S. Geological Survey, 2008c). Daniel Fenner of U.S. Fish and Wildlife Service (written commun., 2006) photographically documented no flow or little flow during mid-August on the reach of the Canadian Cimarron River near Waynoka River near Thomas upstream from the streamflow-gaging site at Bridgeport to near Ada, just upstream from the streamflow- Cimarron River near Waynoka (07158000) is a stream- gaging site at Calvin (fig. 9, appendix 5). flow-gaging site in northwest Oklahoma. Water Year 2006 was the 10th driest in the 69 years of record from 1938–2006, with 42 percent of normal annual flow (table 2). Water Year 2002 was the third driest year, from the 2002–2006 drought North Canadian River near Wetumka period, with 20 percent of normal annual flow. Zero flow was recorded in Water Year 2006 during the first part of August North Canadian River near Wetumka (07242000) is (fig. 12). The lowest flow was at the end of the water year in a streamflow-gaging site in central Oklahoma. Water Year first part of August and last part of September (fig. 12; appen- 2006 was the fourth driest in the 69 years of record from dix 3; U.S. Geological Survey, 2008c). 1938–2006, with just 26 percent of normal annual flow (table 2). Water Year 1956 was the driest year, from the Cimarron River near Ripley 1952–56 drought period, with 23 percent of normal annual flow. Zero flow was not recorded during Water Year 2006, Cimarron River near Ripley (07161450) is a streamflow- with some wet periods in October, March through June and gaging site in central Oklahoma. Water Year 2006 was the 12th September (fig. 16). The lowest flow was near the end of the driest in the 67 years of record from 1940–2006, with water year in August (fig. 16; U.S. Geological Survey, 2008c). 37 percent of normal annual flow (table 2). Water Year 1953 was the driest year, from the 1952–56 drought period, with 17 percent of normal annual flow. Zero flow was not recorded during Water Year 2006, with some wet periods in October, Salt Fork Red River at Mangum May-July, and August-September (fig. 13). The lowest flow Salt Fork Red River near Mangum (07300500) is a was near the end of the water year in August (fig. 13; appendix streamflow-gaging site in southwest Oklahoma. Water Year 4; U.S. Geological Survey, 2008c). 2006 was the third driest in the 69 years of record from 1938–2006, with just 20 percent of normal annual flow Illinois River near Tahlequah (table 2). Water Year 1940 was the driest year, from the 1929–41 drought period, with 17 percent of normal annual Illinois River near Tahlequah (07196500) is a streamflow. Zero flow was recorded in Water Year 2006 during flow-gaging site in east-central Oklahoma. Water Year 2006 late June through August, with some wet periods in October, was the 8th driest in the 71 years of record from 1936–2006, March through June and late August and September (fig. 17; with just 31 percent of normal annual flow (table 2). Water U.S. Geological Survey, 2008c). Low flow was recorded from Year 1954 was the driest year, from the 1952–56 drought October through March, and some days in April through Sep- period, with 21 percent of normal annual flow. Zero flow was tember (fig. 17). not recorded during Water Year 2006, with some wet periods in May, August, and September (fig. 14). The lowest flow was near the end of the water year in August (fig. 14; U.S. Geo- logical Survey, 2008c). Red River near Gainesville, Texas

Red River near Gainesville, Texas, (07316000) is a Canadian River at Calvin streamflow-gaging site in south-central Oklahoma. Water Year 2006 was the driest in the 70 years of record from 1937–2006, Canadian River at Calvin (07231500) is a streamflow- with just 22 percent of normal annual flow (table 2). Water gaging site in east-central Oklahoma. Water Year 2006 was Year 1953 was second driest year, from the 1952–56 drought the second driest in the 66 years of record from 1939–42, period, with 26 percent of normal flow. Zero flow was not 1945-2006; with just 14 percent of normal annual flow (table recorded during Water Year 2006, with some wet periods in 2). Water Year 1981 was the driest year, from the 1976-81 October, March, May, and September (fig. 18). The lowest drought period, with 13 percent of normal annual flow. Zero flow was near the end of the water year in August (fig. 18, flow was recorded in Water Year 2006 during most of the U.S. Geological Survey, 2008c). 28 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Washita River near Dickson recreational uses for several months. Water in the hydrologic storage systems, rivers and reservoirs, commonly has multiple Washita River near Dickson (07331000) is a streamflow- and competing purposes including flood control, irrigation, gaging site in south-central Oklahoma. Water Year 2006 was recreation, navigation, hydropower, and wildlife habitat. Com- the second driest in the 78 years of record from 1929–2006, petition for this water escalates during drought and conflicts with just 27 percent of normal annual flow (table 2). Water between water users increase substantially (National Drought Year 1964 was the driest year, from the 1961–72 drought Mitigation Center, 2006a). period, with 24 percent of normal annual flow. Zero flow was not recorded during Water Year 2006, with some wet periods in October, March, May, and September (fig. 19). The lowest flow was near the end of the water year in August (fig. 19; Conditions at Major Reservoirs appendix 6; U.S. Geological Survey, 2008c). The hydrologic drought of Water Year 2006 substantially affected the reservoirs in the state. The effects on 31 selected Blue River near Blue major lakes or reservoirs at three times of the water year are presented in table 3 (fig. 22; Oklahoma Water Resources Blue River near Blue (07332500) is a streamflow-gaging Board, 2006b; U.S. Army Corps of Engineers, 2007). Table 3 site in south-central Oklahoma. Water Year 2006 was the fifth shows the conservation storage in these lakes, expressed both driest in the 70 years of record from 1937–2006, with just 31 in terms of volume and percent of conservation storage, on percent of normal annual flow (table 2). Water Year 1956 was October 4, 2006, a few days after the end of the Water Year the driest year, from the 1952-56 drought period, with 2006. On that day the statewide total conservation storage was 12 percent of normal annual flow. Zero flow was not recorded 86.3 percent. Table 3 also compares levels at these reservoirs, during Water Year 2006, with some wet periods in March expressed as percent of conservation storage, on two other through May (fig. 20). The lowest flow was near the end of the days: (1) the levels on December 21, 2005, when the statewide water year in August and September (fig. 20; U.S. Geological total conservation storage was lowest, 84.5 percent, and (2) Survey, 2008c). May 24, 2006, when the statewide total conservation storage was the highest, 96.8 percent. The north-central region of Red River at Arthur City, Texas the state consistently had the highest percent of conservation storage (or wettest) while the southwest region of the state Red River at Arthur City, Texas (07335500) is a stream- consistently had the lowest percent of conservation storage flow-gaging site in southeast Oklahoma. Water Year 2006 was (or driest) at all three times of the water year. Lake Altus at the driest in the 62 years of record from 1945–2006, with just Lugert (site 21, fig. 22) in the southwest region was the driest 25 percent of normal annual flow (table 2). Water Year 1964 reservoir for the entire water year (appendix 7). was the second driest year, from the 1961–72 drought period, Lake Eufaula (site 18, fig. 22) is a good example of the with 38 percent of normal annual flow. Zero flow was not dependence several water-use customers have on the reser- recorded during Water Year 2006, with some wet periods in voirs. Six municipalities, eight rural water districts, a hydro- March through May (fig. 21). The lowest flow was near the electric plant, and natural gas plant all use water from the lake end of the water year in August and September (fig. 21; U.S. in addition to recreational use (Jackson, 2006b). However, it Geological Survey, 2008c). must be noted that the condition of farm ponds across Okla- homa was more drastically affected than the major reservoirs. Hundreds of farm ponds across Oklahoma had completely dried up by January 15, 2006 (Jackson, 2006b). Effects of Low Streamflows

Hydrologic drought is associated with the effects of peri- Hydroelectric Power Generation ods of precipitation deficits on streamflow, lake and reservoir Hydroelectric power in Oklahoma was greatly reduced levels, and ground water. Although all droughts start with pre- during Water Year 2006 because of reduction in available cipitation deficits, hydrologists are more concerned with how streamflow as a result of the hydrologic drought. Table 4 this deficit affects the hydrologic system. Hydrologic droughts illustrates the drastic reduction in hydroelectric power genera- commonly lag the meteorological and agricultural droughts. tion at selected hydroelectric plants from Calendar Year 2005 During hydrologic droughts, precipitation deficiencies take to Water Year 2006. Even though there was a 3-month overlap longer to show up in components of the hydrologic system. between October through December 2005, the Water Year For example, precipitation deficits may result in a rapid deple- 2006 hydroelectric power generation at sites in Oklahoma was tion of soil moisture that has an immediate effect on agricul- only 7 to 47 percent of the Calendar Year 2005 power genera- ture (Jackson, 2006a), but the effect on reservoir levels may tion (table 4). not affect water supply, hydroelectric power production, or Effects of Low Streamflows 29

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06

6,000 Washita River near Dickson, Okla. 5,000 07331000 Unregulated 1929-1960 Regulated 1962-2006 3 4,000 Annual Departure 3 3,000 Median Annual Streamflow 1,400 ft /s 5-year Weighted Average

2,000

1,000

0 in cubic feet per second (ft /s)

-1,000 A

Annual Departure from Median Annual Streamflow, -2,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Washita River near Dickson, Okla. 07331000 40,000 30,000

3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1929-2006 10,000 Regulated 1962-2006 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40 30 Streamflow, in cubic feet per second (ft /s) B 20

10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 19. Washita River near Dickson (A) annual departure from long-term median annual streamflow, water years 1929–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1929–2006. 30 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Hydrologic Droughts 1929-41 1952-56 1961-72 1976-81 2002-06 1,000 Blue River near Blue, Okla. 07332500 Unregulated 1937-2006 750 Annual Departure 3 3 Median Annual Streamflow 254 ft /s 5-year Weighted Average 500

250

in cubic feet per second (ft /s) -250 A

-500

Annual Departure from Median Annual Streamflow, 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 50,000 Blue River near Blue, Okla. 07332500 40,000 30,000

3 Daily-Mean Streamflow Water Year 2006 20,000 Long-Term Daily-Mean Streamflow Water Years 1937-2006 10,000 7,000 5,000 4,000 3,000 2,000

1,000 700 500 400 300 200

100 70 50 40

Streamflow, in cubic feet per second (ft /s) 30 20 B 10 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 20. Blue River near Blue (A) annual departure from long-term median annual streamflow, water years 1937–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1937–2006. Effects of Low Streamflows 31

Hydrologic Droughts 1952-56 1961-72 1976-81 2002-06

20,000 Red River at Arthur City, Texas 07335500 Regulated 1945-2006 15,000 Annual Departure 3 3 Median Annual Stramflow 7,223 ft /s 5-year Weighted Average 10,000

5,000

in cubic feet per second (ft /s) -5,000 A

Annual Departure from Median Annual Streamflow, -10,000 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Water Year

100,000 70,000 60,000 Red River at Arthur City, Texas 07335500 50,000 40,000 3 Daily-Mean Streamflow Water Year 2006 30,000 Long-Term Daily-Mean Streamflow Water Years 1945-2006 20,000 Regulated 1945-2006

10,000 7,000 6,000 5,000 4,000 3,000

2,000

1,000 700 600 500 400 300

Streamflow, in cubic feet per second (ft /s) 200 B

100 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 21. Red River at Arthur City, Texas, (A) annual departure from long-term median annual streamflow, water years 1945–2006 (B) comparing daily-mean streamflow of Water Year 2006 and long-term daily-mean streamflow, water years 1945–2006. 32 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

38° 36° 34°

ARKANSAS 94° MISSOURI 27 31 7 ( Neosho River 19 29 8 30 6 Verdigris River 18 28 11 5 24 96° 96° 4 9

River 12 16 10

Arkansas 25 3 River 23

Canadian 17 15

River 98° River 26 98° 2

Cimmaron Washita 13 TEXAS 20

River

River KANSAS 22

Red 14 Canadian River

Red 21 1

North Fork 100° North 100° Miles 100 Kilometers 100 50 102° EXPLANATION 50 25 102° <50% 51 - 70% 71 - 80% 81 - 90% 91 - 100% County Boundary Rivers 25 State Boundary Line Rivers from U.S. Environmental Protection Agency River Reach File versionAlbers 1. Equal-Area Projection. North American Datum 1983. Reservoir Storage Percent of Conservation Storage as of October 4, 2006 Numbers at reservoir locations correspond to table 3 0 0 COLORADO

E MEXICO NEW -~ ------.- ...... --.....-.. -- ... -""- -""----- ...- Figure 22. Locations of selected major lakes and reservoirs in Oklahoma percent Conservation Storage as October 4, 2006. 36° 34° Effects of Low Streamflows 33

Table 3. Storage in selected major Oklahoma lakes and reservoirs during October 4, 2006, by National Weather Service Climate Division, and comparison with December 21, 2005, and May 24, 2006, storage. —Continued

[Shading indicates reservoir storage below 80 percent of total conservation storage; WY, Water Year]

2-North Central 1 Fort Supply 13,900 9,888 71.1 98.6 97.8 2 Great Salt Plains 31,420 25,986 82.7 100.0 98.1 3 Kaw* 375,160 375,160 100.0 100.0 100.0 Regional Totals/Averages 420,480 411,034 97.8 100.0 99.8 3-Northeast 4 Birch 19,225 16,665 86.7 71.1 97.4 5 Copan 34,634 27,817 80.3 75.9 100.0 6 Fort Gibson 365,200 361,087 98.9 98.7 100.0 7 Grand 1,672,000 1,509,910 90.3 88.9 99.6 8 Hudson 200,300 195,802 97.8 83.8 100.0 9 Hulah 22,565 20,240 89.7 66.0 100.0 10 Keystone 512,307 418,770 81.7 78.1 100.0 11 Oologah 552,219 510,351 92.4 88.8 100.0 12 Skiatook 322,700 228,371 70.8 83.9 86.7 Regional Totals/Averages 3,701,150 3,289,013 88.9 87.2 98.6 4-West Central 13 Canton 111,310 74,178 66.6 97.1 100.0 14 Foss 165,480 136,940 82.8 91.6 92.2 Regional Totals/Averages 276,790 211,118 76.3 93.8 95.3 5-Central 15 Arcadia 27,520 27,502 99.9 97.2 100.0 16 Heburn 7,105 5,691 80.1 88.0 100.0 17 Thunderbird 119,600 78,486 65.6 85.4 80.3 Regional Totals/Averages 154,225 111,679 72.4 87.7 84.7 6-East Central 18 Eufaula* 2,314,583 1,967,711 85.0 74.1 92.9 19 Tenkiller 654,100 602,009 92.0 77.7 100.0 Regional Totals/Averages 2,968,683 2,569,720 86.6 74.9 94.4 7-Southwest 20 Fort Cobb 80,010 72,710 90.9 100.0 100.0 21 Altus 132,830 10,508 7.9 37.6 48.8 22 Tom Steed 88,970 40,510 45.5 70.7 61.6 34 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

[Shading indicates reservoir storage below 80 percent of total conservation storage; WY, Water Year]

Percent of conservation storage Conservation 10/04/06 Site Climate Division storage storage number Lake or Reservoir WY end WY driest WY wettest (acre-feet) (acre-feet) a b c (fig. 22) 10/4/2006 12/21/2005 5/24/2006 Regional Totals/Averages 301,810 123,728 41.0 63.9 66.1 8-South Central 23 Arbuckle 72,400 63,165 87.2 95.9 100.0 24 McGee Creek 113,930 96,505 84.7 89.6 100.0 25 Texoma* 2,556,122 2,257,985 88.3 92.4 100.0 26 Waurika* 190,200 139,059 73.1 93.3 89.2 Regional Totals/Averages 2,932,652 2,556,714 87.2 92.4 99.3 9- Southeast 27 Broken Bow* 954,175 796,073 83.4 77.5 97.4 28 Hugo* 158,617 158,617 100.0 66.5 100.0 29 Pine Creek* 53,750 53,750 100.0 80.6 100.0 30 Sardis 274,330 252,137 91.9 90.1 100.0 31 Wister 60,162 47,915 79.6 62.6 100.0 Regional Totals/Averages 1,501,034 1,308,492 87.2 78.0 98.4 State Totals 12,256,824 10,581,498 86.3 84.5 96.8 Reservoirs below 80 percent Storage 8 11 2 * indicates seasonal pool operation; actual storage figures/percents may vary a WY end, 10/4/2006, approximates end of WY 2006 State Total Conservation Storage (Oklahoma Water Resources Board, 2006a). b WY driest, 12/21/2005, approximates lowest State Total Conservation Storage for WY 2006 (Oklahoma Water Resources Board, 2005). c WY wettest, 5/24/2006, approximates highest State Total Conservation Storage for WY 2006 (Oklahoma Water Resources Board, 2006b).

Ground Water at a Long-Term Site acres and more than a dozen homes were lost (Knapp, 2006). Governor Brad Henry issued a statewide burn ban in Novem- A long-term recording ground-water well that has a close ber 2005 that remained in effect, though discontinued several hydraulic connection between streams and the aquifer illus- times, until the last counties were removed from the ban on trates the effect the Water Year 2006 drought had on ground- December 4, 2006. water levels in south-central Oklahoma. Figure 23 shows the daily ground-water levels in the Fittstown well during Water Year 2006 (red line; U.S. Geological Survey, 2007f) compared to the long-term mean-daily water level (blue line; U.S. Summary Geological Survey, 2008e). The water level was almost 17 feet lower than normal in March; although, late spring rains caused Water Year 2006 (October 1, 2005, to September 30, a rise in water levels in May. At the end of the water year the 2006) was a year of extreme hydrologic drought and the dri- water level was more than 9 feet lower than normal. est year in the recent 2002–2006 drought in Oklahoma. The severity of this recent drought can be evaluated by comparing Wildfires it with four previous major hydrologic droughts, water years 1929–41, 1952–56, 1961–72, and 1976–81. Fire danger was critical because of the drought starting in The period of water years 1925–2006 was selected as the November 2005. Hundreds of homes had been destroyed and period of record because before 1925 few continuous record nearly 600,000 acres were burned by January 2006 (Knapp, streamflow-gaging sites existed and gaps existed where no 2006; Slater, 2006). In a 24-hour period starting January 1, streamflow-gaging sites were operated. Statewide annual pre- 2006, more than 30 separate fires burned more than 81,000 cipitation in Water Year 2006 was second driest with Summary 35

72 percent of normal precipitation and statewide annual runoff below-normal streamflow reached 80 to 85 percent for some in Water Year 2006 was sixth driest in the 82 years of record. days in August and November 2006. Annual area-averaged precipitation totals by the nine Twelve long-term streamflow-gaging sites with periods National Weather Service Climate Divisions from Water Year of record ranging from 62 to 78 years were selected to show 2006 are compared to those during four previous major hydro- how streamflow deficits varied by region. The hydrologic logic droughts in the 20th century to show how rainfall deficits drought worsened going from north to south in Oklahoma, in Oklahoma varied by region. Only two of the nine climate ranging from 45 percent in the north, to just 14 percent in divisions, Climate Division 1 Panhandle and Climate Division east-central Oklahoma, and 20 percent of normal annual 4 West Central, had minor rainfall deficits, with streamflow in the southwest. The Chikaskia River near Black- 85 percent or more of normal precipitation; while the rest of well and the Cimarron River near Waynoka in north-central the climate divisions had severe rainfall deficits in Water Year Oklahoma had 45 and 42 percent of normal annual streamflow 2006 ranging from only 65 to 73 percent of normal annual during Water Year 2006, respectively. The Canadian River precipitation. The East Central, Southwest, and South Central at Calvin in east-central Oklahoma had only 14 percent of Climate Divisions were hardest hit with only 65 to 67 percent normal annual streamflow, the second driest year in 66 years; of normal annual precipitation. the Salt Fork Red River near Mangum in southwest Oklahoma Regional streamflow patterns for Water Year 2006 indi- had only 20 percent of normal annual streamflow, the third cate that Oklahoma was part of the regionwide below-normal driest in the 69 years of record and the Red River near Gaines- streamflow conditions for Arkansas-White-Red River Basin, ville in south-central Oklahoma had only 22 percent of normal the sixth driest since 1930. The percentage of long-term sta- annual streamflow, the driest year in 70 years. tions in Oklahoma (with at least 30 years of record) having Some effects of low streamflows during Water Year 2006 include (1) major reservoirs had only 86.3 percent of

Table 4. Comparison of hydroelectric power generation at selected Oklahoma hydroelectric plants between Calendar Year 2005 and Water Year 2006.

[GWh, Gigawatt-hour; CY, calendar year]

Calendar Year Water Year 2006 Site Lake 2005 Percent of number hydroelectric Climate division Power power CY 2005 (fig.22) generation project (GWh) (GWh) power

3 Kaw 1 2-North Central 130 36 28 6 Fort Gibson 2 3-Northeast 231 46 20 7 Grand (Pensacola) 3 3-Northeast 452 101 22 8 Hudson (RS Kerr) 3 3-Northeast 235 40 17 8 Salina 3, 4 3-Northeast 276 130 47 10 Keystone 2 3-Northeast 310 113 36 18 Eufaula 2 6-East Central 192 13 7 19 Tenkiller 2 6-East Central 95 21 22 27 Broken Bow 2 9-Southeast 98 29 30

1 Data from Oklahoma Municipal Power Authority (OMPA) Calendar Year 2005 data from R. Morecroft (OMPA, written commun., 2008). Water Year 2006 data from D. Osburn (OMPA, written commun., 2008). 2 Data from Department of Energy, Southwestern Power Administration (SWPA), Calendar Year 2005 data from J. Croton (SWPA, written commun., 2007), and Water Year 2006 data from Southwestern Power Administration (2007). 3 Data from Grand River Dam Authority (GRDA). All data from A. Bishop (GRDA, written commun., 2007) 4 Salina Pumped Storage Project, Chimney Rock Reservoir. Water used on the Salina Creek Arm of Lake Hudson, classified as offstream project. 36 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

90 Fittstown Ground-Water Well 01N-06E-04 CAD 1 95 Daily Water Level Water Year 2006 Long-Term Mean Daily Water Level Water Years 1981-2006 100

105

110

115

120 Daily water level, feet below land surface

125 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

Figure 23. Fittstown ground-water well, comparing daily water levels for Water Year 2006 and long-term mean-daily water levels, water years 1981–2006.

the statewide conservation storage available at the end of Cole-Frowe, Carol, 2007, Water puzzle − State struggles with the water year, (2) hydroelectric power generation at sites uneven water supply: Enid News, November 28, 2007, in Oklahoma was only 7 to 47 percent of the Calendar Year accessed December 12, 2007 at http://www.enidnews. 2005 power generation, (3) ground water at a long-term site in com/waterstories/local_story_332113854.html/resources_ south-central Oklahoma had a drop in water level of more than printstory 17 feet lower than normal, and (4) wildfires burned more than 600,000 acres. Egan, Timothy, 2006, The worst hard time: New York, Hough- ton Mifflin Company, 340 p. Hoyt, J.C., 1936, Droughts of 1930-34: U.S. Geological Sur- Selected References vey Water Supply Paper 680, 106 p. Hoyt, J.C., 1938, Drought of 1936: U.S. Geological Survey Bisbee, Julie, 2006, Lack of rain forces producers to sell Water Supply Paper 820, 62 p. cattle: The Oklahoman, July 11, 2006, accessed March 6, 2008, at http://www.newsok.com/article/keyword/2000621/ Holmes, R.R., Jr., 2008, Drought − Perceptions, effects, and assessment: U.S. Geological Survey, 3 p., accessed Febru- Blazs, R.L., Walters, D.M., Coffey, T.E., Boyle, D.L., and ary 6, 2008, at http://il.water.usgs.gov/hydro_conditions/ Wellman, J.J., 2007, Water resources data, Oklahoma, water drought_intro.html year 2006: U.S. Geological Survey Water-Data Report OK-06-1, 394 p. Selected References 37

Hutchison, M.A., 2000, Several Oklahoma cities remain flush National Climatic Data Center, 2007b, State Climate Division with plentiful water sources: The Oklahoman, July 24, monthly total precipitation data, Calendar Year 1895–2006, 2000, accessed July 25, 2000, at http://www.oklahoman. file drd964x.pcp.txt: National Climatic Data Center, com/cgi-in/shart?ID=520839&TP=getarticle accessed May 9, 2007, at http://www1.ncdc.noaa.gov/pub/ data/cirs/drd964x.pcp.txt Jackson, Ron, 2006a, Farmers, ranchers feeling drain of persistent drought conditions: The Oklahoman, July 11, 2006, National Climatic Data Center, 2007c, Climate of 2006, accessed March 6, 2008, at http://www.newsok.com/article/ annual review U.S. drought, January 11, 2007: National keyword/2000620/ Climatic Data Center, accessed May 9, 2007, at http://www. ncdc.noaa.gov/oa/climate/research/2006/ann/drought- Jackson, Ron, 2006b, When will the rain come?: The summary.html Oklahoman, January 15, 2006, accessed March 10, 2008, at http://olive.newsok.com/APA26136/PrintArt. National Drought Mitigation Center, 2006a, What is drought? asp?SkinFolder=Oklahoman – Understanding and defining drought: National Drought Mitigation Center, accessed September 13, 2006, at http:// Jian, Xiaodong, Wolock, D.M., and Lins, H.F., 2007, Stream- www.drought.unl.edu/whatis/concept.htm flow of 2006, water year summary: U.S. Geological Survey, accessed January 10, 2008, at http://water.usgs.gov/waterwa National Drought Mitigation Center, 2006b, What is drought? tch/2006summary/#regional – Drought in the dust bowl years: National Drought Mitiga- tion Center, accessed September 13, 2006, at http://www. Johnson, Cullen, 1956, City to buy land for lake: The drought.unl.edu/whatis/dustbowl.htm Oklahoman, December 19, 1956, accessed March 11, 2008, at http://olive.newsok.com/APA26136/PrintArt. National Drought Mitigation Center, 2007, U.S. Drought asp?SkinFolder=Oklahoman Monitor: National Drought Mitigation Center, accessed December 21, 2007, at http://www.drought.unl.edu/dm/ Knapp, Adam, 2006, Oklahoma under burn ban as wild fires monitor.html rage across state: About.com, March 16, 2006, accessed March 6, 2008, at http://www.newsok.com/article/ Oklahoma Climatological Survey, 2005, Oklahoma Climate keyword/1788696/ - Winter 2005-2006: Oklahoma Climatological Survey, accessed January 18, 2008, at http://climate.mesonet.org/ McNutt, Michael, 2006a, Ag department declares state a seasonal_summary.html natural disaster area: The Oklahoman, March 16, 2006, accessed March 6, 2008, at http://www.newsok.com/article/ Oklahoma Climatological Survey, 2006a, Oklahoma Climate keyword/1788696/ - Spring 2006: Oklahoma Climatological Survey, accessed January 18, 2008, at http://climate.mesonet.org/seasonal_ McNutt, Michael, 2006b, Gov. issues statewide burn ban: The summary.html Oklahoman, August 2, 2006, accessed March 6, 2008, at http://www.newsok.com/article/keyword/2824513/ Oklahoma Climatological Survey, 2006b, Oklahoma Climate - Summer 2006: Oklahoma Climatological Survey, accessed McNutt, Michael, 2006c, Burn ban lifted for some: The January 18, 2008, at http://climate.mesonet.org/seasonal_ Oklahoman, September 13, 2006, accessed March 31, summary.html 2008, at http://olive.newsok.com/APA26136/PrintArt. asp?SkinFolder=Oklahoman Oklahoma Climatological Survey, 2006c, Oklahoma Climate - Fall 2006: Oklahoma Climatological Survey, accessed Nace, R.L. and Pluhowski, E.J., 1965, Drought of 1950’s with January 18, 2008, at http://climate.mesonet.org/seasonal_ special reference to the Midcontinent: U.S. Geological summary.html Survey Water Supply Paper 1804, 88 p. Oklahoma Climatological Survey, 2008a, Percentage of National Agricultural Statistics Service, 2007, Oklahoma normal rainfall, water year 2006: Oklahoma Climatologi- agricultural statistics 2007: National Agricultural Statistics cal Survey, accessed January 16, 2008, at http://climate. Service, 107 p. mesonet.org/rainfall/2006waterpct.gif National Climatic Data Center, 2007a, Statewide monthly total Oklahoma Climatological Survey, 2008b, Departure from nor- precipitation data, Calendar Year 1895–2006, file drd964x. mal rainfall, inches, water year 2006: Oklahoma Climato- pcpst.txt: National Climatic Data Center, accessed May 9, logical Survey, accessed January 16, 2008, at http://climate. 2007, at http://www1.ncdc.noaa.gov/pub/data/cirs/ drd964x. mesonet.org/rainfall/2006waterdel.gif pcpst.txt Oklahoma Climatological Survey, 2008c, Drought Monitoring Tools: Oklahoma Climatological Survey, accessed January 18, 2008, at http://climate.mesonet.org/rainfall_update.html 38 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Oklahoma Water Resources Board, 2005, Oklahoma Water U.S. Geological Survey, 2007b, Automated data processing Resources Bulletin and summary of current conditions, system (ADAPS), Daily Values Monthly and Annual Statis- December 21, 2005: Oklahoma Water Resources Board, tics (DVMAS): U.S. Geological Survey. accessed October 5, 2006, at http://www.owrb.ok.gov/ supply/drought/pdf_dro/2005/189_1221_2005.pdf U.S. Geological Survey, 2007c, Drought watch — USGS Streamflow information on drought: U.S. Geological Sur- Oklahoma Water Resources Board, 2006a, Oklahoma Water vey, accessed November 27, 2007, at http://water.usgs.gov/ Resources Bulletin and summary of current conditions, waterwatch/?m=pa07d_dry&r=ok&w=pa07a_dry%2Cplot October 4, 2006: Oklahoma Water Resources Board, accessed October 5, 2006, at http://www.owrb.ok.gov/ U.S. Geological Survey, 2007d, National Water Information supply/drought/pdf_dro/2006/209_1004_2006.pdf System, web interface, USGS surface-water daily data for Oklahoma: U.S. Geological Survey, accessed November 27, Oklahoma Water Resources Board, 2006b, Oklahoma Water 2007, at http://waterdata.usgs.gov/ok/nwis/dv/?referred_ Resources Bulletin and summary of current conditions, module=sw May 24, 2006: Oklahoma Water Resources Board, accessed October 5, 2006, at http://www.owrb.ok.gov/supply/drought/ U.S. Geological Survey, 2007e, Automated data processing pdf_dro/2006/200_0524_2006.pdf system (ADAPS), Daily Values Daily Summary Statistics (DVDAYSTAT): U.S. Geological Survey. Oklahoma Water Resources Board, 2007a, Hydrologic drought of Water Year 2006 – A historical context: Oklahoma Water U.S. Geological Survey, 2007f, National Water Information Resources Board, 4 p. System, web interface, USGS ground-water daily data for Oklahoma: U.S. Geological Survey, accessed November 27, Slater, Grant, 2006, How DRY can it get?: The Oklahoman, 2007, at http://waterdata.usgs.gov/ok/nwis/dv/?referred_ July 2, 2006,accessed March 6, 2008 at http://www.newsok. module=gw com/article/keyword/1882166/ U.S. Geological Survey, 2008a, Streamflow of 2006 Southwestern Power Administration, 2007, 2004-2006 Annual – Water Year Summary: U.S. Geological Survey, report: Southwestern Power Administration, accessed accessed January 10, 2008, at http://water.usgs.gov/ October 17, 2008, at http://www.swpa.gov/PDFs/SWPA_ waterwatch/2006summary/ FY2004-2006_annual_report.pdf U.S. Geological Survey, 2008b, U.S. Geological Survey Sutter, J. D., 2006, Drought continues to wither state: The Photographic Library, Oklahoma: U.S. Geological Sur- Oklahoman, September 3, 2006. vey, accessed February 22, 2008, at http://libraryphoto. cr.usgs.gov/cgi-bin/search.cgi?search_mode=noPunct; Tortorelli, R.L., 2002, Statistical summaries of streamflow in free_form=Oklahoma;free_form=;free_form=;free_ Oklahoma through 1999: U.S. Geological Survey Water- form=;start=50 Resources Investigations Report 02–4025, 510 p. U.S. Geological Survey, 2008c, Water-resources data for the Tortorelli, R.L., Cooter, E.J., and Schuelein, J.W., 1991, Okla- United States, Water Year 2006: U.S. Geological Survey, homa – Floods and droughts, in U.S. Geological Survey, accessed March 6, 2008, at http://wdr.water.usgs.gov/ National water summary 1988-1989 – Hydrologic events wy2006/search.jsp and floods and droughts: U.S. Geological Survey Water- Supply Paper 2375, p. 451–458. U.S. Geological Survey, 2008d, National Water Information System, web interface, USGS ground-water-level daily U.S. Army Corps of Engineers, 2007, Tulsa district water con- statistics for Oklahoma: U.S. Geological Survey, accessed trol home page: U.S. Army Corps of Engineers, accessed October 20, 2008, at http://waterdata.usgs.gov/ok/nwis/ March 13, 2007, at http://www.swt-wc.usace.army.mil/ dvstat/?referred_module=gw U.S. Geological Survey, 2007a, Water watch − Past stream- Vance, Brian, ed., 2007, Oklahoma water atlas: Oklahoma flow conditions – Table of computed median runoff (mm/ Water Resources Board, 190 p. day), by water-year, for Oklahoma: U.S. Geological Sur- vey, accessed January 11, 2007, at http://water.usgs.gov/ waterwatch/?m=statesum&r=ok Appendixes 39

Appendixes 40 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma Appendixes 41

07151000 Salt Fork Arkansas River at Tonkawa August 6, 2006

Appendix 1. Salt Fork of Arkansas River at Tonkawa (0751000), showing low flow, 30 cubic feet per second, looking upstream from U.S. Highway 77 bridge, August 6, 2006. Photographer: Jim Norvell, USGS.

07152000 Chikaskia River near Blackwell August 6, 2006

Appendix 2. Chikaskia River near Blackwell (07152000), showing low flow, 74 cubic feet per second, looking downstream from State Highway 11 bridge, August 6, 2006. Photographer: Jim Norvell, USGS. 42 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

07158000 Cimarron River near Waynoka August 9, 2006

Appendix 3. Cimarron River near Waynoka (07158000), showing low flow, 0.17 cubic foot per second, looking downstream from U.S. Highway 281 bridge, August 9, 2006. Photographer: Marty Phillips, USGS.

., 07161450 Cimarron River near Ripley August 11, 2006

Appendix 4. Cimarron River near Ripley (07161450), showing low flow, 55 cubic feet per second, looking upstream toward State Highway 33 bridge, August 11, 2006. Photographer: Marty Phillips, USGS. Appendixes 43

f -- samohTraenreviRnaidanaC 6002,11tsuguA ------

07228500 Canadian River at Bridgeport August 11, 2006

Appendix 5. Canadian River upstream to downstream, August 11, 2006: (A) near Thomas, showing no flow, looking upstream from State Highway 33 bridge (B) at Bridgeport (07228500), showing low flow and pools, 2.9 cubic feet per second, looking upstream from U.S. Highway 281 bridge. All photographs: David Fenner, USFWS, and locations are shown on fig. 9. —Continued 44 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

Canadian River near Union City August 11, 2006

07229200 Canadian River at Purcell August 11, 2006

Appendix 5. Canadian River upstream to downstream, August 11, 2006: (C) near Union City, showing no flow and pools, looking upstream from State Highway 81 bridge (D) at Purcell (07229200), showing low flow and pools, 4.2 cubic feet per second, looking upstream from U.S. Highway 77 bridge. All photographs: David Fenner, USFWS, and locations are shown on fig. 9. —Continued Appendixes 45

ettenaWraenreviRnaidanaC 6002,11tsuguA

adAraenreviRnaidanaC .- 6002,61tsuguA '.1, ••". •

Appendix 5. Canadian River upstream to downstream: (E) near Wanette, showing no flow, looking upstream from State Highway 102 bridge, August 11, 2006 (F) near Ada, showing no flow, looking downstream from State Highway 99 bridge, August 16, 2006. All photographs: David Fenner, USFWS, and locations are shown on fig. 9. 46 Hydrologic Drought of Water Year 2006 Compared with Four Major Drought Periods of the 20th Century in Oklahoma

07331000 Washita River near Dickson August 22, 2006

Appendix 6. Washita River near Dickson (07331000), showing low flow and pools, 5.7 cubic feet per second, looking downstream from U.S. Highway 177 bridge, August 22, 2006. Photographer: Ernest Smith, USGS.

sutlAekaL 6002,22tsuguA

Appendix 7. Lake Altus at Lugert (07302500), showing very low lake elevation, 7.7 percent of conservation storage, looking upstream from dam, August 22, 2006. Photographer: Martin Schneider, USGS. Back Cover: Picture of children in the Sam Noble Oklahoma Museum of Natural History summer program walking on Lake Thunderbird’s shoreline, Cleveland County, Oklahoma, published July 2, 2006. Photographer: Steve Sisney. Copyright 2006, The Oklahoma Publishing Company.

Publishing support provided by: Lafayette Publishing Service Center

For more information concerning this publication, contact: Director, USGS Oklahoma Water Science Center 202 NW 66th St., Bldg. 7 Oklahoma City, OK 73116 (405) 810-4400

Or visit the Oklahoma Water Science Center Web site at: http://ok.water.usgs.gov Tortorelli, R.L.—Hydrologic Drought of Water Year 2006 Compared with Major Drought Periods in Oklahoma—Scientific Investigations Report 2008–5199 Children walking on the shoreline of Lake Thunderbird. Photograph by Steve Sisney. Copyright 2006, The Oklahoma Publishing Company. Printed on recycled paper