Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States

STREAMFLOW ANALYSIS OF THE APALACHICOLA, PEARL, TRINITY, AND NUECES RIVER BASINS, SOUTHEASTERN UNITED STATES

By Karen E. Greene and Raymond M. Slade, Jr.

U.S. GEOLOGICAL SURVEY Water-Resources Investigations 95-4043

Prepared in cooperation with the U.S. ENVIRONMENTAL PROTECTION AGENCY GULF OF MEXICO PROGRAM

Austin, Texas 1995 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Gordon P. Eaton, Director

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

For additional information write to: Copies of this report can be purchased from:

U.S. Geological Survey Earth Science Information Center District Chief Open-File Reports Section U.S. Geological Survey Box 25286, Mail Stop 517 8011 Cameron Rd. Denver Federal Center Austin, TX 78754-3898 Denver, CO 80225-0046 CONTENTS

Abstract ...... 1 Introduction ...... ^ 1 Purpose and Scope ...... 2 Acknowledgments ...... 2 Approach ...... 2 Selection of Basins ...... 2 Selection of Streamflow Stations and Precipitation Stations ...... 2 Determination of Temporal Trends ...... 4 Analysis of Surface-Water Withdrawals ...... 4 Analysis of Selected Reservoirs by Streamflow Characteristics ...... 4 Streamflow Analyses ...... 5 Apalachicola River Basin ...... 5 Streamflow Stations and Associated Precipitation Stations ...... 5 Temporal Trends in Streamflow and Precipitation ...... 5 Surface-Water Withdrawals ...... 5 Effects of Reservoirs on Streamflow ...... 5 Pearl River Basin ...... 17 Streamflow Stations and Associated Precipitation Stations ...... 17 Temporal Trends in Streamflow and Precipitation ...... 17 Surface-Water Withdrawals ...... 19 Effect of Reservoir on Streamflow ...... 19 Trinity River Basin ...... 21 Streamflow Stations and Associated Precipitation Stations ...... 21 Temporal Trends in Streamflow and Precipitation ...... 22 Surface-Water Withdrawals ...... 33 Effects of Reservoirs on Streamflow ...... 35 Nueces River Basin ...... 43 Streamflow Stations and Associated Precipitation Stations ...... 43 Temporal Trends in Streamflow and Precipitation ...... 44 Surface-Water Withdrawals ...... 45 Effects of Reservoirs on Streamflow...... 45 Summary and Conclusions ...... 49 Selected References ...... 55

FIGURES

1. Map showing location of the Apalachicola, Pearl, Trinity, and Nueces River Basins ...... 3 2. Map showing location of selected Streamflow stations, precipitation stations, and major reservoirs in the Apalachicola River Basin ...... 6

CONTENTS iii 3-12. Graphs showing short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station: 3. 02333500 on the Chestatee River near Dahlonega, Georgia, in the Apalachicola River Basin ...... 7 4. 02335000 on the Chattahoochee River near Norcross, Georgia, in the Apalachicola River Basin ...... ^^^ 8 5. 02337000 on Sweetwater Creek near Austell, Georgia, in the Apalachicola River Basin ...... 9 6. 02339500 on the Chattahoochee River at West Point, Georgia, in the Apalachicola River Basin ...... ^^^^^^ 10 7. 02344500 on the Flint River near Griffin, Georgia, in the Apalachicola River Basin ...... 11 8. 02349500 on the Flint River at Montezuma, Georgia, in the Apalachicola River Basin ...... 12 9. 02352500 on the Flint River at Albany, Georgia, in the Apalachicola River Basin ...... 13 10. 02353500 on Ichawaynochaway Creek at Milford, Georgia, in the Apalachicola River Basin ...... 14 11. 02358700 on the Apalachicola River near Blountstown, Florida, in the Apalachicola River Basin ...... 15 12. 02359000 on the Chipola River near Altha, Florida, in the Apalachicola River Basin ...... 16 13-15. Graphs showing: 13. Reported annual surface-water withdrawals from the Apalachicola River Basin, by category of use ...... 17 14. Predicted peak streamflow at streamflow station 02335000 on the Chattahoochee River downstream from Lake Sidney Lanier in the Apalachicola River Basin, before and after construction of the dam in 1956 ...... 18 15. Predicted peak streamflow at streamflow station 02358700 on the Apalachicola River downstream from Lake Seminole in the Apalachicola River Basin, before and after construction of the dam in 1954 ...... 19 16. Map showing location of selected streamflow stations, precipitation stations, and the major reservoir in the Pearl River Basin ...... 23 17-23. Graphs showing short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station: 17. 02482000 on the Pearl River at Edinburg, Mississippi, in the Pearl River Basin ...... 25 18. 02483000 on Tuscolameta Creek at Walnut Grove, Mississippi, in the Pearl River Basin ...... 26 19. 02484000 on the Yockanookany River near Kosciusko, Mississippi, in the Pearl River Basin ...... 27 20. 02486000 on the Pearl River at Jackson, Mississippi, in the Pearl River Basin ...... 28 21. 02488500 on the Pearl River near Monticello, Mississippi, in the Pearl River Basin ...... 29 22. 02489500 on the Pearl River near Bogalusa, Louisiana, in the Pearl River Basin ...... 30 23. 02492000 on the Bogue Chitto near Bush, Louisiana, in the Pearl River Basin ...... 31 24. Map showing location of selected streamflow stations, precipitation stations, and major reservoirs in the Trinity River Basin ...... 32 25-28. Graphs showing short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station: 25. 08044000 on Big Sandy Creek near Bridgeport, Texas, in the Trinity River Basin ...... 33 26. 08047500 on the Clear Fork Trinity River at Fort Worth, Texas, in the Trinity River Basin ...... 34 27. 08048000 on the West Fork Trinity River at Fort Worth, Texas, in the Trinity River Basin ...... 35 28. 08055500 on the Elm Fork Trinity River near Carrollton, Texas, in the Trinity River Basin ...... 36 29-30. Graphs showing short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station: 29. 08057000 on the Trinity River at Dallas, Texas, in the Trinity River Basin ...... 37 30. 08062500 on the Trinity River near Rosser, Texas, in the Trinity River Basin ...... 38 31. Graphs showing short-term trends in annual mean streamflow and annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08063500 on Richland Creek near Richland, Texas, in the Trinity River Basin ...... 39 32-33. Graphs showing short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station: 32. 08065000 on the Trinity River near Oakwood, Texas, in the Trinity River Basin ...... 40 33. 08066500 on the Trinity River at Romayor, Texas, in the Trinity River Basin ...... 41 iv 34. Graph showing reported annual surface-water withdrawals from the Trinity River Basin, by category of use ...... 45 35-37. Graphs showing short-term trends in annual index precipitation and in annual mean streamflow, and total reported annual surface-water withdrawals from the subbasin upstream from streamflow station: 35. 08057000 on the Trinity River at Dallas, Texas ...... 46 36. 08062500 on the Trinity River near Rosser, Texas ...... 47 37. 08066500 on the Trinity River at Romayor, Texas ...... 48 38. Graph showing predicted peak streamflow at streamflow station 08047500 on the Clear Fork Trinity River downstream from Benbrook Lake in the Trinity River Basin, before and after construction of the dam in 1952 ...... 49 39. Graph showing predicted peak streamflow on the East Fork Trinity River downstream from Lavon Lake in the Trinity River Basin, before and after construction of the dam in 1954 ...... 50 40. Map showing location of selected streamflow stations, precipitation stations, and major reservoirs in the Nueces River Basin ...... 51 41.-43. Graphs showing: 41. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08190000 on the Nueces River at Laguna, Texas, in the Nueces River Basin ...... 52 42. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08194000 on the Nueces River at Cotulla, Texas, in the Nueces River Basin ...... 53 43. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08195000 on the Frio River at Concan, Texas, in the Nueces River Basin ...... 54 44-47. Graphs showing short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station: 44. 08198000 on the Sabinal River near Sabinal, Texas, in the Nueces River Basin ...... 55 45. 08205500 on the Frio River near Derby, Texas, in the Nueces River Basin ...... 56 46. 08208000 on the Atascosa River at Whitsett, Texas, in the Nueces River Basin ...... 57 47. 08210000 on the Nueces River near Three Rivers, Texas, in the Nueces River Basin ...... 58 48. Graphs showing short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08211000 on the Nueces River near Mathis, Texas, in the Nueces River Basin ...... 59 49. Graph showing reported annual surface-water withdrawals from the Nueces River Basin, by category of use ...... 60

TABLES 1. Selected streamflow stations, associated precipitation stations, and periods of record in the Apalachicola River Basin ...... 20 2. Long-term trends in streamflow and associated precipitation for streamflow stations in the Apalachicola River Basin ...... 22 3. Selected streamflow stations, associated precipitation stations, and periods of record in the Pearl River Basin ...... 24 4. Selected streamflow stations, associated precipitation stations, and periods of record in the Trinity River Basin ...... 42 5. Long-term trends in streamflow and associated precipitation for streamflow stations in the Trinity River Basin ...... 44 6. Selected streamflow stations, associated precipitation stations, and periods of record in the Nueces River Basin ...... 60 7. Long-term trends in streamflow and associated precipitation for streamflow stations in the Nueces River Basin ...... 62 8. Water-budget analysis for losses in annual mean streamflow resulting from filling and evaporation at Choke Canyon Reservoir ...... 63

CONTENTS v CONVERSION FACTORS

Multiply______By______To obtain

acre-foot (acre-ft) 1,233 cubic meter cubic foot per second (ft3/s) 0.02832 cubic meter per second inch (in.) 25.4 millimeter inch per year (in/yr) 25.4 millimeter per year mile (mi) 1.609 kilometer mile squared (mi2) 2.59 square kilometer million gallons per day (Mgal/d) 0.04381 cubic meter per second

Water year is defined as the 12-month period from October 1 through September 30. The water year is designated by the calendar year in which it ends. Thus the 1988 water year ends on September 30, 1988.

vi Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States

By Karen E. Greene and Raymond M. Slade, Jr.

Abstract near the mouth. Total withdrawals increased more than eightfold in the Nueces River Basin since Annual mean streamflow and annual mini 1940. Surface-water withdrawals from the Nueces mum and maximum daily mean streamflows were River Basin in 1988 represent about one-third of compared with associated annual index precipita the annual mean streamflow near the mouth. tion for sites on the main channels and tributaries Effects of selected reservoirs on streamflow of four major rivers that discharge directly into the in the four basins also were studied. Predicted Gulf of Mexico. Long- and short-term precipita peak streamflow into the Gulf from the Apalachi tion trends were identified for selected streamflow cola River was about 23 percent less for the 50- stations with at least 40 years of record. year peak streamflow after reservoir construction. Long-term temporal trends in annual mean Although one large reservoir was built on the Pearl streamflow and annual maximum daily mean River and many reservoirs have been built on the streamflow to the Gulf were not identified from the Trinity River and its tributaries, peak streamflow Apalachicola River Basin for the period of record into the Gulf of Mexico from these rivers has not studied. Annual mean and maximum streamflow been affected during the past 50 years. Estimates to the Gulf increased with time from the Pearl from a water-budget analysis showed that the River Basin and decreased from the Trinity River annual mean streamflow to the Gulf from the Basin. Annual mean streamflow showed varied Nueces River was reduced by about 24 percent trends and annual maximum streamflow decreased from 1985 through 1990 as a result of filling and from the Nueces River Basin. Annual minimum evaporation at Choke Canyon Reservoir. streamflow to the Gulf increased in all of the basins studied. The annual index precipitation INTRODUCTION associated with the most downstream station also The U.S. Environmental Protection Agency ini increased during the periods of record studied in tiated the Gulf of Mexico Program (GMP) to develop all four of the basins. Short-term trends in stream- and implement a comprehensive strategy for managing flow generally corresponded to trends in associ and protecting the resources of the Gulf of Mexico. The ated annual index precipitation for each station. objective of the Program is to achieve a balance For some streamflow stations in the Trinity River between the preservation and enhancement of living Basin, short-term trends in annual minimum marine resources and the needs and demands of human streamflow increased while annual maximum activities. One of the Program's subcommittees, the streamflow decreased. Freshwater Inflow Committee, is responsible for assessing inflow to the Gulf from streams. The quantity Total reported surface-water withdrawals and temporal distribution of freshwater inflow affect have increased more than fourfold in the Trinity the delivery of nutrients to bays and estuaries and River Basin since 1940. Surface-water withdraw influence other ecological factors important to the spe als from the Trinity River Basin in 1988 represent cies that live in the Gulf of Mexico. This report was about one-fourth of the annual mean streamflow prepared by the U.S. Geological Survey (USGS) in

Abstract cooperation with the Freshwater Inflow Committee of record, only the common period of record was used for the GMP. comparison of the trends. A previous report was prepared by the USGS for Trends were identified by straight-line regres the Committee (U.S. Environmental Protection sions and "best-fit" curves of the data. Annual mean Agency, 1992). The report presented, for each of 44 and annual maximum streamflow data tend not to be major streams discharging directly to the Gulf, tempo normally distributed; therefore, a robust fitting proce ral trends in streamflow to the Gulf. dure was used. Curvilinear graphs of streamflow and precipitation data thus were produced without giving Purpose and Scope undue weight to outlying values. Possible causes for changes in streamflow are The purpose of this report is to present temporal inferred from trend comparisons; trends in streamflow trends in streamflow and associated precipitation at are compared to trends in precipitation, to surface- selected sites in four major river basins that discharge water withdrawals (where available), and to reservoir directly to the Gulf of Mexico. Selected sites with at development within each basin. The effects of reser least 40 years of data were included in the study, which voirs on streamflow were based on comparisons of generally includes data through 1988. Trends in sur peak streamflow for various recurrence intervals (such face-water withdrawals in each basin also are reported as 50 years) and, for two reservoirs, on comparisons of where sufficient data were available, and effects of res the statistical relations between precipitation and ervoirs on streamflow are presented for selected sites. streamflow for the periods before and after the con struction of each reservoir. Acknowledgments The authors thank Howard Liljestrand, a Civil Selection of Basins Engineering teacher at the University of Texas at Aus The four basins chosen for the study are the tin, for reviewing this report and B.A. Moulton of the Apalachicola River Basin in Georgia, Alabama, and Texas Natural Resource Conservation Commission and Florida; the Pearl River Basin in Mississippi and Loui the other members of the Freshwater Inflow Committee siana; and the Trinity River and Nueces River Basins in for their support in the preparation of this report. Texas (fig. 1). These basins were chosen because of their geographic distribution and diversity in hydrol APPROACH ogy, climate, land use, and extent of development. A Trends were determined for annual mean stream- variety of factors affect streamflow in these four basins. flow discharge and annual minimum and maximum Major factors are identified and described, and major daily mean streamflow discharges for 7 to 10 long-term reasons for trends in streamflow are explained. streamflow stations in each of the 4 basins. Annual Selection of Streamflow Stations and mean streamflow is the mean gaged streamflow at each Precipitation Stations site for each year. Annual minimum daily mean streamflow is the mean gaged streamflow for the day with the Streamflow stations in each basin were selected smallest mean streamflow during the year. Annual from the long-term stations (those with more than 40 maximum daily mean streamflow is the mean gaged consecutive years of daily streamflow data) operated streamflow for the day with the largest mean stream- by the USGS. The most downstream long-term station flow during the year. Precipitation trends are based on on the main channel in each basin was included for mean values of annual precipitation for representative analysis. Other stations on the main channel and a few long-term precipitation stations in the basin upstream on tributaries also were selected to represent areas of from each streamflow station. different geography, climate, and land use. All avail The available records for streamflow, precipita able data were retrieved from the USGS for each sta tion, and surface-water withdrawals vary among sites. tion (U.S. Geological Survey, 1981). Methods and For all of the selected stations, trends for the available accuracy of streamflow data collection are described by period of continuous record were presented for stream- Rantz and others (1982). flow. For sites where the length of the associated pre For each streamflow station selected for cipitation record exceeded the length of streamflow analysis, two to seven spatially distributed long-term

Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States "w ~~£ CO 8 0>~~

~~co IT 1 jo"a. 8 lc o J5~~

~~O) il~~

APPROACH precipitation stations operated by the National Ocean- mined for sites for which at least about one-quarter of ographic and Atmospheric Administration (NOAA) the annual minimum daily mean streamflow values were selected to represent the annual index precipita were zero. tion in the basin upstream from each station. Precipita tion stations were selected because of their geographic Analysis of Surface-Water Withdrawals spacing and period of record coincident to the streamflow stations. Precipitation data for each station were Surface-water withdrawal data were obtained collected by NOAA (U.S. Department of Commerce, from State agencies and from reports of the USGS. The 1889-1989). The mean of the total annual precipitation data represent the reported surface-water withdrawals for the stations in or near the basin upstream from a from basins upstream from individual streamflow sta streamflow station was used to estimate the annual tions. Data concerning return flows to the rivers were index precipitation for that basin. Only those years with not readily available and therefore not included in the at least 11 complete months (fewer than 3 missing study. About one-half of the volumes withdrawn for days) of record at a precipitation station were included. municipal use might be returned to streams. Industrial The number of stations selected for each basin was not and irrigation withdrawals are considered as consump sufficient to define the spatial variability of precipita tive uses by the Texas Natural Resource Conservation tion over the basin. Commission.

Determination of Temporal Trends Analysis of Selected Reservoirs by Streamflow Characteristics Long-term trends and short-term trends in streamflow and associated precipitation were identified One to three major reservoirs in each river basin for the period of record used for each streamflow sta were selected to characterize the effects of reservoir tion included in the study. Trends in precipitation were operations on streamflow. A surface-water impound compared with trends in streamflow for each of the sta ment with greater than 5,000 acre-ft of storage was tions. Long-term trends were identified by a "best-fit" considered to be a major reservoir. All reservoirs straight-line regression of the data. A positive slope of selected for analysis had at least 20 years of continuous the line indicates a trend of long-term increasing val record before and 20 years of continuous record after ues, and a negative slope indicates a trend of long-term construction of the reservoir, at a station directly down decreasing values. To indicate a long-term trend, an stream from the reservoir. These records provide suffi increase or decrease greater than 5 percent was selected cient data for analyses of predicted peak streamflow at for streamflow, and an increase or decrease greater than each station. Peak streamflow frequency analysis using 3 percent was selected for precipitation. These percent U.S. Water Resources Council (1981) guidelines was values probably exceed the potential gaging error in the performed for each station for the periods of record data. before and after reservoir construction. Predicted peak The LOcally WEighted Regression and Smooth streamflows for the two periods of record then were ing Scatterplots (LOWESS) technique, described by compared for each station. Cleveland (1979), was used to identify short-term For reservoirs with sufficient data, the relations trends in the data. For each data value, LOWESS pro of streamflow to precipitation during the periods of duces a best-fit curvilinear trend using a weighting fac record before and after reservoir construction were tor to consider a specific range of the data. A factor of compared. For each year, the mean streamflow was 10 percent was used for the precipitation data, meaning converted to the depth of runoff, in inches, over the that each point on the trend line was based on the 10 drainage area associated with the station. A linear percent of the data surrounding that point. A factor of regression was produced for each period using annual 25 percent was used for the streamflow data. These fac index precipitation as the independent variable and the tors were used to produce LOWESS curves with simi common logarithm of runoff as the dependent variable. lar amplitudes for presentation and comparison of A water-budget analysis was performed for one reser trends. The smaller factor was used for precipitation voir to estimate the volume of streamflow that was data because precipitation values varied less than reduced in the river downstream from the reservoir streamflow values. Short-term trends were not deter because of filling and evaporation.

Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States STREAMFLOW ANALYSES 02335000 (downstream from Lake Sidney Lanier) and station 02358700 (downstream from Lake Seminole), Apalachicola River Basin the short-term trends in annual mean streamflow corre sponded with the short-term trends in precipitation The Apalachicola River Basin, located in Geor (figs. 3 and 11), whereas long-term trends in annual gia, Alabama, and Florida, has a drainage area of minimum and maximum daily mean streamflow corre approximately 20,500 mi2. The annual mean streamflow at the mouth of the river basin is approximately sponded to long-term trends in precipitation for some stations (table 2). For stations 02344500 and 25,000 ft3/s. Mean annual precipitation in the basin 02349500, streamflow during the 1980's decreased ranges from about 45.5 in. at Montezuma, Georgia, to while precipitation during the same period showed lit about 65.7 in. at Cleveland, Georgia. The Chatta- tle change (figs. 7 and 8). For some of the stations hoochee River joins the Flint River at Lake Seminole where the period of record for streamflow is longer on the Georgia-Florida border and becomes the than the period of record for precipitation, the short- Apalachicola River downstream from that reservoir term trends for precipitation did not correspond to the (fig. 2). Five reservoirs with capacities exceeding 5,000 trends in streamflow for the early years of the precipi acre-ft were identified in the basin. tation record; sufficient data probably were not avail Streamflow Stations and Associated Precipitation able for the LOWESS procedure to identify the same Stations trends for those years. Six streamflow stations on the main channels of Surface-Water Withdrawals the Chattahoochee, Flint, and Apalachicola Rivers and four streamflow stations on tributaries were selected Data for surface-water withdrawals are available for analysis. Locations of these stations and associated at 5-year intervals beginning in 1970 for the entire precipitation stations are shown in figure 2. A list of the Apalachicola River Basin (Richard Marella, U.S. Geo selected streamflow stations and precipitation stations logical Survey, written commun., 1991). The data are and their available periods of record is presented in presented in figure 13. Most of the industrial withdraw table 1. als represent thermoelectric power generation. Data are insufficient to identify trends in surface-water with Temporal Trends in Streamflow and Precipitation drawals from the Apalachicola River Basin.

Long-term temporal trends in annual mean Effects of Reservoirs on Streamflow streamflow and annual maximum daily mean streamflow at the most downstream station (02358700) were Streamflow measurements downstream from not evident during the period of record studied (table two reservoirs, Lake Sidney Lanier and Lake Seminole 2). Annual minimum daily mean streamflow to the (fig. 2), were analyzed for flood frequencies before and Gulf increased. Long-term trends in associated annual after construction of the dams in 1956 and 1954, index precipitation indicated an increase during the respectively. Predicted peak streamflow for selected period of record for the drainage basins above all but recurrence intervals was calculated for the long-term two of the selected streamflow stations. Precipitation streamflow station immediately downstream from each decreased for the drainage basin above station reservoir (figs. 14 and 15). The predicted peak stream- 02353500 and did not change for the drainage basin flow before construction of the reservoir was compared above station 02359000. The streamflow for two sta to that after construction at each site. Predicted peak tions (02339500 and 02349500) decreased while pre streamflow was about 74 percent and 23 percent less cipitation increased. For smaller watersheds, such as for 50-year floods at stations downstream from Lake station 02353500, conflicting trends might be the result Sidney Lanier and Lake Seminole, respectively, fol of changes in the patterns of precipitation over the lowing reservoir construction. basin and the resulting streamflow at the station. A statistical analysis of the relations between Generally, the short-term trends identified for precipitation and streamflow was made for the station annual mean streamflow corresponded to those for on the Apalachicola River near Blountstown, Florida, associated annual index precipitation (figs. 3-12). Dur downstream from Lake Seminole. Reservoirs upstream ing the second half of the period of record for station from Lake Seminole also may affect streamflow at this

~~STREAMFLOW ANALYSES -Toccoa~~

~~Bmbrv~~

~~Swf etwatfr Creek~~

~~WALTER F. GEORGE RESERVOIR~~

~~EXPLANATION .... DRAINAGE BASIN BOUNDARY~~

~~- SUBBASIN BOUNDARY~~

~~02352500 STREAMFLOW STATION AND NUMBER Milford CITY Blakely CITY WITH PRECIPITATION STATION~~

~~GULF Of~~

~~10 20 30 40 MILES~~

~~0 10 20 30 40 KILOMETERS~~

~~Figure 2. Location of selected streamflow stations, precipitation stations, and major reservoirs in the Apalachicola River Basin.~~

~~6 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 500~~

~~400~~

~~300 CO~~

~~200 150~~

~~100~~

~~8,000~~

~~6,000~~

~~2,000~~

~~xz 70~~

50 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 3. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02333500 on the Chestatee River near Dahlonega, Georgia, in the Apalachicola River Basin.

~~STREAMFLOW ANALYSES 3,000~~

~~2,500~~

~~_. ZUJID 2,000~~

~~1,500~~

~~800~~

~~600~~

~~400 20,000~~

~~10'000~~

~~xz 60~~

~~40 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 4. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02335000 on the Chattahoochee River near Norcross, Georgia, in the Apalachicola River Basin.

~~8 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 500~~

~~400~~

~~4,000 -~~

~~2,000 60~~

~~40 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 5. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02337000 on Sweetwater Creek near Austell, Georgia, in the Apalachicola River Basin.

~~STREAMFLOW ANALYSES 9 7,000~~

~~5,000~~

~~4,000 2,000~~

~~1,500~~

~~1,000~~

~~500~~

~~0 60,000~~

~~40,000~~

~~IS-3 0" 20,000~~

~~0 60~~

~~40 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 6. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02339500 on the Chattahoochee River at West Point, Georgia, in the Apalachicola River Basin.

~~10 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 500~~

~~400~~

~~CO 300~~

~~200~~

~~tocc 20~~

~~0 6,000~~

~~4,000~~

~~2,000 55~~

~~45 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 7. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02344500 on the Flint River near Griffin, Georgia, in the Apalachicola River Basin.

~~STREAMFLOW ANALYSES 11 5,000~~

~~Ijttui 4,000~~

~~3,000~~

~~2,000 1,200 p&§ 1'000~~

~~1^§1 800~~

~~600~~

~~400 40,000~~

~~30,000~~

~~20,000~~

~~10,000 55~~

~~xz 50~~

~~if 45~~

~~40 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 8. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02349500 on the Flint River at Montezuma, Georgia, in the Apalachicola River Basin.

~~12 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 7,000 ii 6'°°°~~

~~5,000~~

~~4,000 1,500~~

~~llSi*% 1-°°°~~

~~500~~

~~so.ooo~~

~~20,000 55~~

~~a 50~~

~~4o45~~

~~40 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 9. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02352500 on the Flint River at Albany, Georgia, in the Apalachicola River Basin.

~~STREAMFLOW ANALYSES 13 1,000~~

~~800 -~~

~~600~~

~~400 300~~

~~200~~

~~100 8,000~~

~~6,000~~

~~4,000~~

~~2,000 70~~

~~xz 60~~

~~40 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 10. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02353500 on Ichawaynochaway Creek at Milford, Georgia, in the Apalachicola River Basin.

~~14 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 30,000~~

~~1 25,000~~

~~20,000~~

~~15,000 12,000~~

~~10,000~~

~~8,000~~

~~6,000 * 120,000 i So 100,000~~

~~i~ 80,000 -~~

~~60,000 60~~

~~40 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 11. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02358700 on the Apalachicola River near Blountstown, Florida, in the Apalachicola River Basin.

~~STREAMFLOW ANALYSES 15 2,000~~

~~1,000 700~~

~~600~~

~~500~~

~~400 8,000~~

~~6,000~~

~~4,000~~

~~2,000 65~~

~~xz 60~~

~~50 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 12. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02359000 on the Chipola River near Altha, Florida, in the Apalachicola River Basin.

~~16 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States £.,UUU i i i i i 4,000~~

~~0 TOTAL~~

~~0 INDUSTRIAL O 3,500 A MUNICIPAL 0 Q 2,000 CC D IRRIGATION Q UJ 3,000 § Q. 0 O w UJ O c/) Q 2,500 2 § 1 '500 O Z o UJ o o o B 3 2,000 o ^ CD D -. 1,000 - O 1,500 ? 1 CC Q - 1,000 < 1 500 - Q~~

~~A A 500 ^ A A~~

~~A D D D n m Q i i i 1965 1970 1975 1980 1985 1990 1995 WATER YEAR~~

Figure 13. Reported annual surface-water withdrawals from the Apalachicola River Basin, by category of use. station. Before construction of the reservoir, the annual about 62.3 in. in the downstream part of the basin. One mean streamflow was about 17 percent of the associ major reservoir is in the basin. ated annual index precipitation; streamflow was about 16 percent of precipitation after construction of the res Streamflow Stations and Associated Precipitation ervoir. Therefore, streamflow as a percentage of precip Stations itation was about 1 percent less after construction of the reservoir, which represents a decrease in streamflow of Four streamflow stations on the main channel of about 6 percent. This decrease, however, probably the Pearl River and three streamflow stations on tribu exceeds the potential error in the data, thus it is possible taries were chosen for analysis. Locations of selected that no change in streamflow occurred. long-term streamflow stations and precipitation sta tions in the Pearl River Basin are shown in figure 16. Pearl River Basin The selected streamflow stations and associated precip itation stations and their available periods of record are The Pearl River Basin, located in Mississippi and listed in table 3. Louisiana, has a drainage area of approximately 8,730 mi2. The annual mean streamflow is approximately Temporal Trends in Streamflow and Precipitation 9,500 ft3/s at the most downstream station (02489500) (fig. 16). Mean annual precipitation in the basin ranges The long-term trends indicate increases in from about 55.8 in. in the upstream part of the basin to streamflow and precipitation at all but one of the

~~STREAMFLOW ANALYSES 17 70,000~~

~~O O BEFORE DAM CONSTRUCTION O LJJ O AFTER DAM CONSTRUCTION V) 60,000 CC LJJ Q_~~

~~LJJ 50,000 O CD 40,000 § 30,000 -~~

~~20,000 ffi Q 10,000 O Q LJJ CC D_ 20 40 60 80 100 120 RECURRENCE INTERVAL, IN YEARS~~

Figure 14. Predicted peak streamflow at streamflow station 02335000 on the Chattahoochee River downstream from Lake Sidney Lanier in the Apalachicola River Basin, before and after construction of the dam in 1956.

selected sites in the Pearl River Basin: annual mean annual maximum streamflow and in associated annual streamflow, annual minimum and maximum daily index precipitation during the same period (fig. 20). mean streamflow, and associated annual index precipi For station 02488500 (farther downstream), annual tation all increased during the period of record. The minimum streamflow increased during the late 1970's exception was streamflow station 02492000, where and 1980's, while annual mean and annual maximum less than a 5-percent increase occurred in annual mini streamflow and annual index precipitation decreased mum streamflow. Increases occurred at this station for annual mean and annual maximum streamflow and for for the station during the same period (fig. 21). For sta associated annual index precipitation. tion 02489500 (the most downstream station studied on the main channel), annual mean streamflow decreased The short-term trends identified for the stream- during the 1980's, while annual minimum streamflow flow generally corresponded to the trends in associated annual index precipitation for each station (figs. IT- increased, and annual index precipitation and annual 23). The trends for streamflow station 02486000 maximum streamflow decreased and then increased (downstream from the Ross R. Barnett Reservoir) indi during the same period (fig. 22). Causes for these cated an increase in annual minimum streamflow dur trends were not investigated; however, the increases ing the 1980's and a decrease in annual mean and in annual minimum streamflow could result from

~~18 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States (-) oau ,\J\J\J I I I 1 I~~

~~O 0 O BEFORE DAM CONSTRUCTION LJJ 2 300,000 <> AFTER DAM CONSTRUCTION LU ^_^^^^ Q_ r^^^ LJJ ^^^ £ 250,000 O ^ CD / &^_.--'--*-"""""" _.---' <> z 200,000 /.""""" 3 2 150,000 ©/' LJJ~~

~~1 t * 100,000 'i LJJ Q_ Q [5 50,000 - Q LJJ DC 3) Q. 0 i i i i i 0 20 40 60 80 100 15 RECURRENCE INTERVAL, IN YEARS~~

Figure 15. Predicted peak streamflow at streamflow station 02358700 on the Apalachicola River downstream from Lake Seminole in the Apalachicola River Basin, before and after construction of the dam in 1954. reservoir operation and from return flows from Jack period of record and lack of information about other son, Mississippi. possible surface-water withdrawals, these data were insufficient for determining trends in surface-water Surf ace-Water Withdrawals withdrawals in the Pearl River Basin.

Data for surface-water withdrawals were avail Effect of Reservoir on Streamflow able for only two major users: Jackson, Mississippi, and the Georgia-Pacific Co. (Nancy Barber, U.S. Geo The Ross R. Baraett Reservoir is the only major logical Survey, written commun., 1991). The City of reservoir in the Pearl River Basin (fig. 16). This reser Jackson reported annual mean withdrawals from the voir was built primarily for water supply and probably Pearl River ranging from 38.2 to 50.4 ft3/s from 1975 has not affected peak streamflow in the Pearl River. through 1985. The withdrawal for the city is used for Peak streamflow frequency analyses of streamflow municipal water supply, supplemented with ground- downstream from the reservoir before and after con water withdrawals, and is returned to the Pearl River as struction of the reservoir in 1965 indicate that the treated effluent. From 1979 through 1986, the Georgia- predicted peak streamflow did not change following Pacific Co. reported annual mean withdrawals from the completion of the reservoir. The annual index precipi Pearl River north of Monticello, Mississippi (fig. 16), tation following reservoir construction was about ranging from 30.0 to 43.2 ft3/s. Because of the limited 7 in. more than before construction of the reservoir;

STREAMFLOW ANALYSES 19 Table 1. Selected streamflow stations, associated precipitation stations, and periods of record in the Apalachicola River Basin [Where the period of record for the associated precipitation stations exceeded the available period of record for the streamflow station, the longest common period of record was used for analysis of trends for the streamflow station and its associ ated precipitation stations]

~~Precipitation station Available periods of record Streamflow station number and name number and location (water years)~~

~~02333500 Chestatee River 1929-32, 1940-88 near Dahlonega, Ga. 2006 Cleveland, Ga. 1948-88 2475 Dahlonega, Ga. 1930-88~~

~~02335000 Chattahoochee River 1903-46, 1957-88 near Norcross, Ga. 2475 Dahlonega, Ga. 1930-88 3621 Gainesville, Ga. 1930-88 6407 Norcross, Ga. 1948-88 8740 Toccoa, Ga. 1930-88~~

~~02337000 Sweetwater Creek 1904-06, 1937-88 near Austell, Ga. 2791 Douglasville, Ga. 1948-88 3147 Embry, Ga. 1948-88~~

~~02339500 Chattahoochee River 1896-88 at West Point, Ga. 451 Atlanta, Ga. 1930-88 2475 Dahlonega, Ga. 1930-88 3147 Embry, Ga. 1948-88 3621 Gainesville, Ga. 1930-88~~

~~9291 West Point, Ga. 1930-88~~

~~02344500 Flint River near Griffin, Ga. 1937-88 451 Atlanta, Ga. 1930-88 3271 Experiment, Ga. 1926-88~~

~~02349500 Flint River at Montezuma, Ga. 1905-13,1930-88 451 Atlanta, Ga. 1930-88 3271 Experiment, Ga. 1926-88 5979 Montezuma, Ga. 1948-88 6335 Newnan, Ga. 1948-88~~

~~8535 Talbotton, Ga. 1930-88~~

20 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States Table 1. Selected streamflow stations, associated precipitation stations, and periods of record in the Apalachicola River Basin Continued

~~Precipitation station Available periods of record Streamflow station number and name number and location (water years)~~

~~02352500 Flint River at Albany, Ga. 1902-21, 1930-88 140 Albany, Ga. 1892-88 451 Atlanta, Ga. 1930-88 3271 Experiment, Ga. 1926-88 8535 Talbotton, Ga. 1930-88~~

~~02353500 Ichawaynochaway Creek 1905-08,1940-88 at Milford, Ga. 979 Blakely, Ga. 1889-1911,1914-88 2450 Cuthbert, Ga. 1948-88 2570 Dawson, Ga. 1944-88~~

~~02358700 Apalachicola River 1921-88 near Blountstown, Fla. 140 Albany, Ga. 1892-88 451 Atlanta, Ga. 1930-88 979 Blakely, Ga. 1889-1911, 1914-88 3261 Gainesville, Ga. 1930-88~~

~~3271 Experiment, Ga. 1926-88 7424 Quincy,Fla. 1896-98,1901-04,1916-67 7429 Quincy, Fla. 1968-88 9291 West Point, Ga. 1930-88~~

02359000 Chipola River near Altha, Fla. 1913-14,1922-27,1929-31,1943-88 804 Blountstown, Fla. 1931-82 979 Blakely, Ga. 1889-1911, 1914-88 6218 Ozark,Ala. 1930-86 7429 Quincy, Fla. 1968-88 therefore, peak streamflow frequencies and statistical annual precipitation in the basin ranges from about relations between precipitation and streamflow for the 28.8 in. in the upstream part of the basin to about 52.2 two periods cannot be compared meaningfully. in. in the downstream part of the basin. The Trinity River has 31 identified reservoirs in the basin with a Trinity River Basin capacity greater than 5,000 acre-ft of storage.

The Trinity River, located entirely in the State of Streamflow Stations and Associated Precipitation Texas, has a drainage area of approximately 18,000 *^. Stations mi . The annual mean streamflow is approximately 7,400 ft3/s at station 08066500, about 94 mi upstream Four streamflow stations on the main channel of from the mouth of the Trinity River (fig. 24). Mean the Trinity River and five stations on major tributaries

STREAMFLOW ANALYSES 21 Table 2. Long-term trends in streamflow and associated precipitation for streamflow stations in the Apalachicola River Basin [no change, less than 5-percent increase or decrease for 50 years of streamflow record, or less than 3-percent increase or decrease for 50 years of precipitation record]

~~Long-term trend Annual Annual Associated Streamflow station number and name Annual mean minimum maximum annual index streamflow daily mean daily mean precipitation streamflow streamflow~~

02333500 Chestatee River increased no change increased increased near Dahlonega, Ga. 02335000 Chattahoochee River no change no change decreased increased1 near Norcross, Ga. 02337000 Sweet water Creek increased no change increased increased1 near Austell, Ga.

02339500 Chattahoochee River decreased decreased decreased increased at West Point, Ga. 02344500 Flint River near Griffin, Ga. no change no change decreased increased 02349500 Flint River at decreased decreased decreased increased Montezuma, Ga.

02352500 Flint River at Albany, Ga. no change increased increased increased 02353500 Ichawaynochaway Creek decreased decreased increased decreased1 at Milford, Ga. 02358700 Apalachicola River no change increased no change increased1 near Blountstown, Fla.

~~02359000 Chipola River near no change decreased no change no change Altha, Fla.~~

1 Comparison of streamflow trends with the precipitation trend for this site may be affected by the shorter length of record for the precipitation stations associated with this streamflow station. were selected for analysis. Locations of the long-term selected streamflow stations in the Trinity River Basin streamflow stations and precipitation stations selected (table 5). Associated annual index precipitation either for analysis in the Trinity River Basin are shown in fig increased with time or remained unchanged throughout ure 24. The selected streamflow stations, associated the basin. Annual mean streamflow decreased at six of precipitation stations, and their available periods of the nine streamflow stations. Annual mean streamflow record are presented in table 4. increased for station 08047500, downstream from Ben- brook Lake, and for station 08057000. Annual mean Temporal Trends in Streamflow and Precipitation streamflow did not change for station 08055500, down stream from Grapevine Lake and Lewisville Reservoir. Long-term trends indicated an increase in annual Short-term trends in annual mean streamflow minimum daily mean streamflow and a decrease in generally corresponded to the trends identified for annual maximum daily mean streamflow for all of the associated annual index precipitation (figs. 25-33).

~~22 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States \Ackerman '~~

~~Kosciusko 02484000~~

~~Canton~~

~~EXPLANATION - _ DRAINAGE BASIN BOUNDARY~~

~~Brookhaveri, {^ I » - SUBBASIN BOUNDARY City '/ \ 02488500 V \ / \ V S 5 Monticetto \^ 02489500 A STREAMFLOW STATION AND NUMBER~~

~~i 1 /^ M-e, \ Bush B CITY N *N Columbia » CITY WITH PRECIPITATION STATION~~

~~10 20 SO 40 MILES~~

~~0 10 20 30 40 KILOMETERS SA 3V \v, (*°*^£'/ \ n A\Poplarville " V " V '/024895001 /~~

~~S> I 02492000 \B > BushN v~~

~~Covington~~

&& >tf 0*

~~Figure 16. Location of selected streamflow stations, precipitation stations, and the major reservoir in the Pearl River Basin.~~

STREAMFLOW ANALYSES 23 Table 3. Selected streamflow stations, associated precipitation stations, and periods of record in the Pearl River Basin [Where the period of record for the associated precipitation stations exceeded the available period of record for the streamflow station, the longest common period of record was used for analysis of trends for the streamflow station and its associated precipitation stations]

~~Streamflow station number and name Precipitation station number Available periods and location of record~~

~~02482000 Pearl River at Edinburg, Miss. 1929-88 5247 Louisville, Miss. 1930-88 6894 Philadelphia, Miss. 1949-88~~

~~02483000 Tuscolameta Creek 1940-88 at Walnut Grove, Miss. 3107 Forest, Miss. 1930-88 9326 Walnut Grove, Miss. 1948-88~~

~~02484000 Yockanookany River 1939-88 near Kosciusko, Miss. 39 Ackerman, Miss. 1948-88 4776 Kosciusko, Miss. 1948-87, 1989-88~~

~~02486000 Pearl River at Jackson, Miss. 1902-88 1389 Canton, Miss. 1948-88 3107 Forest, Miss. 1930-88 4667 Jackson, Miss. 1930-71 4776 Kosciusko, Miss. 1948-87, 1989-88~~

~~5247 Louisville, Miss. 1930-88~~

~~02488500 Pearl River near Monticello, Miss. 1939-88 1094 Brookhaven City, Miss. 1930-88 1389 Canton, Miss. 1948-88 3107 Forest, Miss. 1930-88 4467 Jackson, Miss. 1931-71~~

~~5247 Louisville, Miss. 1930-88~~

~~02489500 Pearl River near Bogalusa, La. 1939-88 1094 Brookhaven City, Miss. 1930-88 1865 Columbia, Miss. 1930-88 2151 Covington, La. 1930-88 3107 Forest, Miss. 1930-88~~

~~5247 Louisville, Miss. 1930-88 7128 Poplarville, Miss. 1930-88~~

~~02492000 Bogue Chitto near Bush, La. 1938-88 1094 Brookhaven City, Miss. 1930-88 1865 Columbia, Miss. 1930-88 2151 Covington, La. 1930-88~~

~~24 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 2,000~~

~~1,500~~

~~1,000~~

~~500~~

~~20,000~~

~~15,000~~

~~5,000~~

~~40 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 17. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02482000 on the Pearl River at Edinburg, Mississippi, in the Pearl River Basin.

~~STREAMFLOW ANALYSES 25 1,000~~

~~500~~

~~0 15~~

~~15,000~~

~~10,000 -~~

~~5,000~~

~~40 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 18. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02483000 on Tuscolameta Creek at Walnut Grove, Mississippi, in the Pearl River Basin.

~~26 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 600~~

~~400~~

~~200 15~~

~~0 15,000~~

~~10,000~~

~~5,000 -~~

~~xz 60~~

~~20 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 19. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02484000 on the Yockanookany River near Kosciusko, Mississippi, in the Pearl River Basin.

~~STREAMFLOW ANALYSES 27 6,000~~

~~4,000~~

~~2,000 200~~

~~o ig5£ 150 3l8ffi~~

~~100 40,000~~

~~tilo 30,000~~

~~2!^S-0" 20,000~~

~~10,000 70~~

~~xz 60~~

~~40 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 20. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02486000 on the Pearl River at Jackson, Mississippi, in the Pearl River Basin.

~~28 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 10,000~~

~~8,000~~

~~6,000~~

~~w 4,000~~

~~2,000~~

~~800~~

~~600~~

~~400~~

~~1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 21. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02488500 on the Pearl River near Monticello, Mississippi, in the Pearl River Basin.

~~STREAMFLOW ANALYSES 29 15,000~~

~~o £w 10,000~~

~~5,000 2,000~~

~~1,000 60,000~~

~~50,000~~

~~40,000~~

~~30,000~~

~~20,000~~

~~50 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 22. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02489500 on the Pearl River near Bogalusa, Louisiana, in the Pearl River Basin.

~~30 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 2,500~~

~~2,000~~

~~CO 1,500~~

~~1,000 800~~

~~ih35u 600~~

~~400 30,000~~

~~25,000~~

~~20,000~~

~~15,000~~

~~10,000 70~~

~~50 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 23. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 02492000 on the Bogue Chitto near Bush, Louisiana, in the Pearl River Basin.

~~STREAMFLOW ANALYSES 31 Cresson~~

~~\ \ v x *\ N^^v twwcanaCorsicana x ~f \ HastKxo.l \^-~"\* Vx V . / 32'''\r \-4» 'vA^-5^X£%{L% / \~~

~~EXPLANATION _ _ _ DRAINAGE BASIN BOUNDARY~~

~~- SUBBASIN BOUNDARY~~

~~08066500 A STREAMFLOW STATION AND NUMBER Rossier B CITY~~

~~Hillsboro 9 CITY WITH PRECIPITATION STATION~~

~~0 10 20 30 AC MILES~~

~~0 10 20 30 40 KILOMETERS~~

~~Figure 24. Location of selected streamflow stations, precipitation stations, and major reservoirs in the Trinity River Basin.~~

~~32 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 100~~

~~4,000~~

~~-iDo o 2,000~~

~~xz~~~

~~20 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 25. Short-term trends in annual mean streamfiow, annual maximum daily mean streamfiow, and associated annual index precipitation for streamfiow station 08044000 on Big Sandy Creek near Bridgeport, Texas, in the Trinity River Basin.

Trends in annual minimum and maximum daily mean 08044000, 08047500, 08048000,08055500, and streamflow generally did not correspond to trends in 08063500 because of a large number of zero values associated annual index precipitation. Trends in annual present in the data. minimum and maximum streamflow correspond more Surface-Water Withdrawals closely to the trends in annual index precipitation for station 08066500 than for the upstream stations (fig. The Texas Natural Resource Conservation Com 33). Short-term trends were not identified for annual mission has records of water use, by county, for the minimum daily mean streamflow for stations Trinity River Basin dating back to the early 1900's.

~~STREAMFLOW ANALYSES 33 200 Ill 150 CO 100~~

~~CO 50~~

~~0 6,000~~

~~4,000~~

~~2,000~~

~~3 35~~

20 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 26. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08047500 on the Clear Fork Trinity River at Fort Worth, Texas, in the Trinity River Basin.

Total reported annual surface-water withdrawals for not returned to the streams (Texas Water Development the entire Trinity River Basin since 1940 are shown, by Board, written commun., 1990). category of use, in figure 34. Withdrawals in the basin Data for surface-water withdrawals for the sub- have increased more than fourfold since 1940. Most of basins upstream from three streamflow stations this increase resulted from withdrawals for municipal (08057000,08062500, and 08066500) were compared water supplies; withdrawals for industrial uses also with trends in annual mean streamflow and associated have increased. However, only about 20 percent of the annual index precipitation at each station (figs. 35-37). reported withdrawals in 1990 were consumed and were Withdrawals have increased in the basin upstream from

~~34 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 600~~

~~400 -j 0 uj~~

~~CO 200~~

~~0 10,000~~

~~5,000 20.~~

~~xz~ 35~~

20 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 27. Short-term trends in annual mean streamfiow, annual maximum daily mean streamfiow, and associated annual index precipitation for streamfiow station 08048000 on the West Fork Trinity River at Fort Worth, Texas, in the Trinity River Basin. each of these three stations. Total surface-water with Based on identified trends, annual minimum daily drawals from the Trinity River Basin in 1988 repre mean streamflow has increased and annual maximum sented about one-fourth of the annual mean streamflow daily mean streamflow has decreased at all of the at station 08066500, the most downstream station on selected stations (table 5). Numerous reservoirs in the the Trinity River. basin have caused these trends. Increases in annual minimum streamflow resulted from releases from res Effects of Reservoirs on Streamfiow ervoirs to supplement low flow and, downstream from The streamflow at all of the stations selected for Dallas and Fort Worth, discharges of treated waste- analysis probably is affected by upstream regulation. water into the streams. Decreases in annual maximum

~~STREAMFLOW ANALYSES 35 1,500~~

~~1,000~~

~~CO 500~~

~~0 30,000~~

~~20,000~~

~~ZQ- 10,000~~

~~xz 35~~

25 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 28. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08055500 on the Elm Fork Trinity River near Carrollton, Texas, in the Trinity River Basin.

streamflow resulted from attenuation of flood peaks by other upstream reservoirs. Predicted peak streamflow the reservoirs. downstream from Benbrook Lake on the Clear Fork The streamflow at the long-term station immedi Trinity River, for the flood peak with an expected ately downstream from each of three reservoirs, Ben- 'Peak streamflow before construction of Lavon Lake was brook Lake, Lavon Lake1 , and Livingston Reservoir calculated based on the period of record from 1924-53 for station (fig. 24), was analyzed for peak streamflow frequency 08061500. Peak streamflow after construction of Lavon Lake was before and after construction of the reservoirs. Stream- calculated based on the period of record from 1954-89 for station flow at each of these reservoirs may be affected by 08061000.

~~36 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 2,000 lil 1'5°°~~

~~CO 1,000~~

~~500 300~~

~~200~~

~~100~~

~~0 40,000~~

~~30,000~~

~~20,000~~

~~10,000~~

~~20 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 29. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08057000 on the Trinity River at Dallas, Texas, in the Trinity River Basin.

~~STREAMFLOW ANALYSES 37 6,000~~

~~4,000~~

~~2,000~~

~~0 1,000~~

~~500~~

~~o 60,000~~

~~40,000~~

~~i^ 20,000~~

~~xz 40~~

~~20 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 30. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08062500 on the Trinity River near Rosser, Texas, in the Trinity River Basin.

~~38 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 600~~

~~Ssfci 400~~

~~CO 200~~

~~0 30,000~~

~~20,000~~

~~5j r z~ui 10,000~~

~~xz isog 40~~

20 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 31 . Short-term trends in annual mean streamflow and annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08063500 on Richland Creek near Richland, Texas, in the Trinity River Basin. recurrence interval of 50 years, was about 44,600 ft3/s Livingston Reservoir on the main channel of the Trin before and about 22,900 ft3/s after the reservoir was ity River, constructed in 1969, was affected by constructed in 1952 (fig. 38), a decrease of about 49 upstream regulation for at least 15 years before the con percent. Predicted peak streamflow downstream from struction of the reservoir (after 1969). Peak streamflow Lavon Lake on the East Fork Trinity River was about frequency analyses were performed for the period 84,800 ft3/s before and 21,300 ft3/s after the reservoir before upstream regulation and for the period after con was constructed in 1954 (fig. 39), a decrease of about struction of the reservoir. The predicted 50-year peak 75 percent. The streamflow station downstream from streamflow was about 112,000 ft3/s for both periods.

~~STREAMFLOW ANALYSES 39 8,000~~

~~6,000~~

~~4,000~~

~~2,000 1,000~~

~~500~~

~~0 60,000~~

~~iltilo 40,000 1|§ UJ 15- 20,000~~

~~0 45~~

~~xz 40~~

~~25 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 32. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08065000 on the Trinity River near Oakwood, Texas, in the Trinity River Basin.

~~40 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 10,000~~

~~6,000~~

~~4,000 800 i . QOn- _ _J jjjO 600 21"-OS; St LLlZ~~

~~400~~

~~200 50,000~~

~~40,000~~

~~QCC - 30,000~~

~~20,000 45~~

~~xz 40~~

~~30 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 33. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08066500 on the Trinity River at Romayor, Texas, in the Trinity River Basin.

STREAMFLOW ANALYSES 41 Table 4. Selected streamflow stations, associated precipitation stations, and periods of record in the Trinity River Basin [Where the period of record for the associated precipitation stations exceeded the available period of record for the streamflow station, the longest common period of record was used for analysis of trends for the streamflow station and its associ ated precipitation stations]

~~Precipitation station number Available periods Streamflow station number and name and location of record~~

~~08044000 Big Sandy Creek near Bridgeport, Tex. 1937-88 984 Bowie, Tex. 1897-98, 1900-27, 1955-88 1063 Bridgeport, Tex. 1915-46,1948-88~~

~~08047500 Clear Fork Trinity River 1924-88 at Fort Worth, Tex. 691 Benbrook Dam, Tex. 1949-88 2906 Cresson, Tex. 1948-88 9532 Weatherford, Tex. 1902-88~~

~~08048000 West Fork Trinity River 1921-88 at Fort Worth, Tex. 271 Antelope, Tex. 1910-20, 1948-88 1063 Bridgeport, Tex. 1915-46,1948-88 4517 Jacksboro, Tex. 1941-88 9532 Weatherford, Tex. 1902-88~~

~~08055500 Elm Fork Trinity River 1907-88 near Carrollton, Tex. 2404 Denton, Tex. 1913-88 3415 Gainesville, Tex. 1897-98,1900-26, 1928-87 3420 Gainesville, Tex. 1987-88~~

08057000 Trinity River at Dallas, Tex. 1903-88 1063 Bridgeport, Tex. 1915-46, 1948-88 2244 Dallas, Tex. 1897-98, 1900-15, 1948-88 3415 Gainesville, Tex. 1897-98, 1900-26, 1928-87 3420 Gainesville, Tex. 1987-88

~~08062500 Trinity River near Rosser, Tex. 1924-25, 1939-88 1063 Bridgeport, Tex. 1915-46,1948-88 5766 McKinney, Tex. 1903-05,1912-88 9522 Waxahatchie, Tex. 1897-98, 1900-88~~

42 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States Table 4. Selected streamflow stations, associated precipitation stations, and periods of record in the Trinity River Basin Continued

~~Precipitation station number Available periods Streamflow station number and name and location of record~~

~~08063500 Richland Creek near Richland, Tex. 1939-88 2019 Corsicana, Tex. 1897,1901-88 4182 Hillsboro, Tex. 1903-88 5869 Mexia, Tex. 1904-57,1960-88~~

~~08065000 Trinity River near Oakwood, Tex. 1924-88 3415 Gainesville, Tex. 1897-98,1900-26, 1928-87 3420 Gainesville, Tex. 1987-88 4705 Kaufman, Tex. 1901-88 5869 Mexia, Tex. 1904-57,1960-88~~

~~9532 Weatherford, Tex. 1902-88~~

~~08066500 Trinity River at Romayor, Tex. 1924-88 1063 Bridgeport, Tex. 1915^6,1948-88 2019 Corsicana, Tex. 1897,1901-88 2114 Crockett, Tex. 1904-17,1924-88 5196 Liberty, Tex. 1904-88~~

~~5766 McKinney, Tex. 1903-05,1912-88~~

Livingston Reservoir probably has had only minimal Nueces River Basin effects on peak streamflow to the Gulf of Mexico from the Trinity River. The Nueces River Basin (fig. 40) has a drainage area of approximately 17,000 mi2 and annual mean A statistical analysis of the relations between streamflow of about 800 ft3/s at the most downstream precipitation and streamflow was done for the station station (08211000). Mean annual precipitation in the on the Trinity River near Romayor, Texas (08066500), basin ranges from about 20.9 in. in the upstream part of downstream from Livingston Reservoir. Before con the basin to about 27.5 in. in the downstream part. struction of the reservoir, the annual mean streamflow Three reservoirs in the basin have a capacity greater was calculated to be about 4.9 percent of the associated than 5,000 acre-ft of storage. annual index precipitation for the station. After con struction of the reservoir, the annual mean streamflow Streamflow Stations and Associated Precipitation was about 4.7 percent of the associated annual index Stations precipitation. Therefore, streamflow, as a percent of precipitation, was about 0.2 percent less following con Four streamflow stations along the main stem of struction of the reservoir, which represents about a 4- the Nueces River and four streamflow stations on trib percent decrease in streamflow. The decrease, however, utaries were selected for analysis. For each station, two exceeds the potential error in the data, thus any change to seven precipitation stations were selected as indices in streamflow is not observable. to represent the precipitation associated with the

STREAMFLOW ANALYSES 43 Table 5. Long-term trends in streamflow and associated precipitation for streamflow stations in the Trinity River Basin [no change, less than 5-percent increase or decrease for 50 years of streamflow record, or less than 3-percent increase or decrease for 50 years of precipitation record]

~~Long-term trends Annual Annual Associated Streamflow station number and name Annual mean minimum maximum annual index streamflow daily mean daily mean precipitation streamflow streamflow~~

08044000 Big Sandy Creek decreased increased decreased increased near Bridgeport, Tex. 08047500 Clear Fork Trinity River increased increased decreased no change at Fort Worth, Tex. 08048000 West Fork Trinity River decreased increased decreased increased at Fort Worth, Tex.

08055500 Elm Fork Trinity River no change increased decreased increased near Carrollton, Tex. 08057000 Trinity River increased increased decreased no change at Dallas, Tex. 08062500 Trinity River decreased increased decreased increased near Rosser, Tex.

08063500 Richland Creek decreased increased decreased no change near Richland, Tex. 08065000 Trinity River decreased increased decreased no change near Oakwood, Tex. 08066500 Trinity River decreased increased decreased increased at Romayor, Tex. streamflow. Locations of long-term streamflow stations ciated annual index precipitation varied for the selected and precipitation stations and the major reservoirs in stations (table 7). the Nueces River Basin are shown in figure 40. The The short-term trends in streamflow generally selected streamflow stations and precipitation stations corresponded to the short-term trends identified for and their available periods of record for the Nueces associated annual index precipitation (figs. 41-48). For River Basin are presented in table 6. station 08205500, the trends indicated increased pre cipitation during the late 1910's and 1920's, while the Temporal Trends in Streamflow and Precipitation annual mean and maximum streamflow decreased (fig. 45). For stations 08190000 and 08211000 (the most Long-term trends in annual minimum daily mean downstream station studied), the annual minimum streamflow indicated an increase for all of the selected daily mean streamflow showed a general increase dur stations during the period of record studied (table 7). ing the 1970's and 1980's, while annual mean and max Annual maximum daily mean streamflow decreased imum streamflow and annual index precipitation for all of the stations except for station 08198000, decreased (figs. 41 and 48). Short-term trends were not where the trend in annual maximum streamflow identified for annual minimum daily mean streamflow increased. Trends in annual mean streamflow and asso for stations 08194000, 08198000, 08205500,

~~44 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 2,000~~

~~- TOTAL Q z ----- MUNICIPAL O - INDUSTRIAL UJ 1,500 03 --- IRRIGATION DC UJ ...... MINING Q.~~

~~UJ UJ LL O 1,000 O~~

~~1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 WATER YEAR~~

~~Figure 34. Reported annual surface-water withdrawals from the Trinity River Basin, by category of use.~~

~~08208000, and 08210000 because of large numbers of represent about one-third of the annual mean stream- zero values in the data. flow at station 08211000.~~

~~Surface-Water Withdrawals Effects of Reservoirs on Streamflow~~

Records of surface-water withdrawals, by Three major reservoirs are in the Nueces River county, in the Nueces River Basin were obtained from Basin (fig. 40). Upper Nueces Lake has a much smaller the Texas Natural Resource Conservation Commis storage capacity than the other two lakes and was not sion. Reported annual surface-water withdrawals since included in this analysis. Lake Corpus Christi was built 1940 from the Nueces River Basin are shown, by cate in 1934 and enlarged in 1958. Choke Canyon Reser gory of use, in figure 49. Withdrawals by Corpus voir, on the Frio River, began filling in October 1982. Christi, downstream from station 08211000, are not The available periods of record for the stations down considered in this report; however some of the reported stream from these reservoirs were insufficient for anal withdrawals are downstream from this station. Since yses of streamflow before and after construction of the 1940, total surface-water withdrawals from the Nueces reservoirs. The net evaporation rates from the reser River Basin have increased more than eightfold. About voirs were estimated from pan-evaporation data at the one-half of withdrawal represents municipal use. Sur reservoirs using monthly pan-net coefficients (Kane, face-water withdrawals from the Nueces River Basin 1967). The annual mean net evaporation from Choke

~~STREAMFLOW ANALYSES 45 40~~

~~20 2,000 Q 8 i 8 § CC LU W CO 1,500~~

~~ffi O tu m LL R o ° m ~. o 1,000 9 " E! ^~~

~~LU ? CC~~

~~E 500 STREAMFLOW iiLU WITHDRAWALS~~

~~1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 35. Short-term trends in annual index precipitation and in annual mean streamflow, and total reported annual surface-water withdrawals from the subbasin upstream from streamflow station 08057000 on the Trinity River at Dallas, Texas.

Canyon Reservoir is estimated to be about 84,000 acre- storage is 90 percent of that at the spillway. Evapora- ft based on 40 in/yr of net evaporation when storage is tion losses from the two reservoirs are substantial com 90 percent of the capacity at the top of the spillway pared to streamflow from the Nueces River to the Gulf gates. Annual mean net evaporation from Lake Corpus of Mexico, and the long-term mean streamflow to the Christi is estimated to be about 62,000 acre-ft when Gulf is reduced by evaporation from both reservoirs.

~~46 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 50~~

~~xz 40 _jbo~~

~~20 5,000~~

~~8 STREAMFLOW WITHDRAWALS CC LU 4,000 LU CO~~

~~LU r_ O LU § £ 3,000 ^ E5 ~Z OD Q^ Z~~~

~~2,000 - LU~~

~~LU 1,000~~

1940 1950 1960 1970 1980 1990 WATER YEAR Figure 36. Short-term trends in annual index precipitation and in annual mean streamflow, and total reported annual surface-water withdrawals from the subbasin upstream from streamflow station 08062500 on the Trinity River near Rosser, Texas.

A water-budget analysis was prepared for 1965- tion at the reservoir (table 8). Net evaporation losses 90 to estimate the volume of streamflow that was were calculated for each year by multiplying the net reduced in the Nueces River downstream from Choke evaporation depth times the mean surface area of the Canyon Reservoir resulting from filling and evapora reservoir. Station 08210000 on the Nueces River is

~~STREAMFLOW ANALYSES 47 50~~

~~_jbo~~

~~30 10,000 §i a: ft 8,000 LLI tn~~

~~§ O 6,000 ° 55 ~Z OD I s.~~

~~4,000 < ^ LLJ § E cc i 1 i STREAMFLOW u 2,000 WITHDRAWALS~~

~~1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 37. Short-term trends in annual index precipitation and in annual mean streamflow, and total reported annual surface-water withdrawals from the subbasin upstream from streamflow station 08066500 on the Trinity River at Romayor, Texas. downstream from Choke Canyon Reservoir and from upstream stations are 08194500,08205500,08206700, four upstream stations that comprise most of the flow at and 08208000 (fig. 40). Before the reservoir was con- downstream station 08210000. Annual mean stream- structed, the ratio of the downstream streamflow to the flow values were used in this analysis. The four total gaged upstream streamflow was determined to be

~~48 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 50,000~~

~~O O O BEFORE DAM CONSTRUCTION LU c/5 O AFTER DAM CONSTRUCTION u 40,000~~

~~LU It O g 30,000~~

~~1 20,000 LU~~

~~C/5~~

~~°- 10,000 Q~~

~~O Q LU CC Q. 10 20 30 40 50 60 RECURRENCE INTERVAL, IN YEARS~~

Figure 38. Predicted peak streamflow at streamflow station 08047500 on the Clear Fork Trinity River downstream from Benbrook Lake in the Trinity River Basin, before and after construction of the dam in 1952.

1.07, as explained in table 8. After the reservoir began SUMMARY AND CONCLUSIONS receiving inflow, this ratio was multiplied by the total gaged upstream streamflow to estimate the expected For the Apalachicola River, long-term temporal downstream streamflow if losses had not occurred trends in annual mean and annual maximum daily because of filling and evaporation at the reservoir. The mean streamflow at the most downstream station were streamflow reduction at the downstream station caused not evident during the study period. However, long- by filling and evaporation was assumed to be the term trends indicate an increase in annual minimum expected streamflow minus the actual streamflow at the daily mean streamflow and associated annual index downstream station. The total volume reduction, precipitation. Annual mean streamflow was about 6 796,000 acre-ft (183 ft3/s), was similar to the volume, 806,000 acre-ft (185 ft3/s), determined for the sum of percent less for the period following construction of the the total change in storage and the total estimated net most downstream reservoir in the Apalachicola River evaporation losses for the reservoir (table 8). The Basin. The 50-year peak streamflow at stations down streamflow reduction from 1985 through 1990 repre stream from the reservoirs has been reduced by about sented 24 percent of the long-term annual mean 23 percent in the upper part of the basin and about 74 streamflow to the Gulf of Mexico as measured at the percent in the lower part of the basin. The reductions in station on the Nueces River near Mathis, Texas. predicted peak streamflow and the increases in annual

SUMMARY AND CONCLUSIONS 49 100,000 o o O BEFORE DAM CONSTRUCTION LU CO O AFTER DAM CONSTRUCTION rr 80,000 LU UJ O g 60,000 s*

~~40,000 - UJ~~

~~CO 111 °- 20,000 - o o Q UJ O' rr Qu 10 20 30 40 50 60 RECURRENCE INTERVAL, IN YEARS~~

Note: Peak streamflow before construction of the dam in 1954 was calculated based on the period of record from 1924 to 1953 at streamflow station 08061500. Peak streamflow after construction of the dam was calculated based on the period of record from 1954 to 1989 at streamflow station 08061000 (fig. 24).

~~Figure 39. Predicted peak streamflow on the East Fork Trinity River downstream from Lavon Lake in the Trinity River Basin, before and after construction of the dam in 1954.~~

minimum daily mean streamflow probably result partly flow to the Gulf of Mexico from the basin for the period from effects of reservoir operations. studied, while associated annual index precipitation For the Pearl River, annual mean streamflow and increased or remained unchanged. Annual minimum annual minimum and maximum daily mean streamflow daily mean streamflow to the Gulf increased and to the Gulf of Mexico and associated annual index pre annual maximum streamflow decreased, because of cipitation in the basin increased during the period stud reservoir operations in the basin. Surface-water with ied. The increases in streamflow are caused partly by drawals have increased more than fourfold in the Trin increased precipitation on the basin. Predicted peak ity River Basin and as of 1988 represent about one- discharges near the mouth of the Pearl River, however, fourth of the annual mean streamflow at the most did not change as a result of the reservoir in the basin. downstream station studied. Predicted peak streamflow For the Trinity River, long-term trends for most in the upper reaches of the Trinity River were as much stations indicated a decrease in annual mean stream- as 75 percent less following reservoir construction;

~~50 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States i > 8 I""* 5/^ t^ Us s I CD CO ill< LU z I X g § ai Q s> 0 O~~

~~(I)~~

~~TJ (0~~

~~o I'a.~~

~~1 "8~~

~~o>§~~

~~SUMMARY AND CONCLUSIONS 51 250~~

~~200~~

~~150~~

~~CO 100~~

~~50 60 k Ili 40 ill 20~~

~~0 10,000~~

~~5,000~~

~~xz 25~~

15 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 41. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08190000 on the Nueces River at Laguna, Texas, in the Nueces River Basin.

~~52 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 300~~

~~^tj! 200~~

~~CO 100~~

~~0 8,000~~

~~6,000~~

~~4,000 30~~

~~XZ 25~~

~~15 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 42. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08194000 on the Nueces River at Cotulla, Texas, in the Nueces River Basin. however, predicted peak streamflow to the Gulf did not to the Gulf of Mexico from the basin, while annual change following reservoir construction. Predicted minimum daily mean streamflow increased for all but annual mean streamflow as a percentage of precipita one station studied. Trends in annual mean streamflow tion in the basin was about 4 percent less following and associated annual index precipitation varied for the construction of Livingston Reservoir. selected stations. Surface-water withdrawals from the For the Nueces River, long-term trends indicate basin increased more than eightfold from 1940 through decreases in annual maximum daily mean streamflow 1990, and as of 1988 represent about one-third of the

~~SUMMARY AND CONCLUSIONS 53 200~~

~~150~~

~~100~~

~~CO 50~~

~~0 60~~

~~0 6,000~~

~~4,000~~

~~2,000~~

~~xz 30~~

20 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 43. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08195000 on the Frio River at Concan, Texas, in the Nueces River Basin.

~~54 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 100~~

~~0 3,000~~

~~2,000~~

~~1,000~~

~~25 -~~

~~20 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 44. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08198000 on the Sabinal River near Sabinal, Texas, in the Nueces River Basin.

mean annual streamflow from the Nueces River to the SELECTED REFERENCES Gulf of Mexico. Filling and evaporation from Choke Canyon Reservoir from 1985 through 1990 represented Cleveland, W.S., 1979, Robust locally weighted regression about 24 percent of the long-term annual mean stream- and smoothing scatterplots: Journal of the American flow to the Gulf from the Nueces River. Decreases in Statistical Association, v. 74, no. 368, p. 829-836. annual maximum daily mean streamflow are caused Kane, J.W., 1967, Monthly reservoir evaporation rates for partly by reservoir operations in the Nueces River Texas 1940-65: Texas Water Development Board Basin. Report 64, 111 p. '

~~SELECTED REFERENCES 55 200~~

~~100~~

~~0 8,000~~

~~6,000~~

~~4,000~~

~~2,000~~

~~30 T~~

~~xzf~~

20 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 45. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08205500 on the Frio River near Derby, Texas, in the Nueces River Basin.

SELECTED REFERENCES Continued Slade, R.M., Jr., 1992, Status of the Gulf of Mexico pre liminary report on inflows from streams: U.S. Environ Rantz, S.E., and others, 1982, Measurement and computa mental Protection Agency Report EPA 800-R-005, tion of streamflow: U.S. Geological Survey Water- 64 p. Supply Paper 2175, 631 p. U.S. Department of Commerce, 1889-1989, Climatological data, Alabama, Florida, Georgia, Louisiana, Missis Seaber, P.R., Kapinos, P.P., and Knapp, G.L., 1987, Hydro- sippi, Texas, annual summaries: National Oceanic and logic unit maps: U.S. Geological Survey Water-Supply Atmospheric Administration, National Climatic Data Paper 2294, 63 p. Center.

~~56 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 150~~

~~100~~

~~50 CO~~

~~1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 46. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08208000 on the Atascosa River at Whitsett, Texas, in the Nueces River Basin.

SELECTED REFERENCES Continued File Report 79-1336-1, v. 4 [variously paged]. U.S. Water Resources Council, 1981, Guidelines for deter U.S. Geological Survey, 1981, National water data storage mining flood flow frequency: Hydrology Committee and retrieval system: U.S. Geological Survey Open- Bulletin 17B [variously paged].

~~SELECTED REFERENCES 57 1,500~~

~~500 -~~

~~0 20,000~~

~~10,000~~

~~0 30~~

~~20 1910 1920 1930 1940 1950 1960 1970 1980 1990 WATER YEAR~~

Figure 47. Short-term trends in annual mean streamflow, annual maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08210000 on the Nueces River near Three Rivers, Texas, in the Nueces River Basin.

~~58 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States 2,000~~

~~1,000~~

~~100~~

~~0 30,000 .~~

~~20,000~~

~~~ 10,000~~

~~xz 25~~

15 1940 1950 1960 1970 1980 1990 WATER YEAR Figure 48. Short-term trends in annual mean streamflow, annual minimum and maximum daily mean streamflow, and associated annual index precipitation for streamflow station 08211000 on the Nueces River near Mathis, Texas, in the Nueces River Basin.

~~Figure 48 59 250~~

~~TOTAL - MUNICIPAL INDUSTRIAL - IRRIGATION~~

~~1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 WATER YEAR~~

~~Figure 49. Reported annual surface-water withdrawals from the Nueces River Basin, by category of use.~~

~~Table 6. Selected streamflow stations, associated precipitation stations, and periods of record in the Nueces River Basin~~

[Where the period of record for the associated precipitation stations exceeded the available period of record for the streamflow station, the longest common period of record was used for analysis of trends for the streamflow station and its associated precipitation stations]

~~Precipitation station number Available periods Streamflow station number and name and location of record~~

~~08 1 90000 Nueces River at Laguna, Tex. 1924-88 7706 Rocksprings, Tex. 1932-35, 1938, 1941-86 9265 Uvalde, Tex. 1905-85 9268 Uvalde, Tex. 1985-88~~

60 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States Table 6. Selected streamflow stations, associated precipitation stations, and periods of record in the Nueces River Basin Continued

~~Precipitation station number Streamflow station number and name Available periods and location of record~~

08 1 94000 Nueces River at Cotulla, Tex. 1927-88 1007 Brackettville, Tex. 1900-31, 1935-88 1486 Carrizo Springs, Tex. 1912-17, 1928-72 1975-88 2048 Cotulla, Tex. 1901-07,1911-16 1922-88 9265 Uvalde, Tex. 1905-85

~~9268 Uvalde, Tex. 1985-88~~

~~08 1 95000 Frio River at Concan, Tex. 1924-29, 1931-88 4780 Kerrville, Tex. 1897, 1901-74 4782 Kerrville, Tex. 1974-88 7873 Sabinal, Tex. 1903-46, 1948-88~~

~~08 1 98000 Sabinal River near Sabinal, Tex. 1943-88 4780 Kerrville, Tex. 1897, 1901-74 4782 Kerrville, Tex. 1974-88 7873 Sabinal, Tex. 1903-46, 1948-88~~

~~08205500 Frio River near Derby, Tex. 1915-88 2458 Dilley, Tex. 1910-87 4254 Hondo, Tex. 1900-75 4256 Hondo, Tex. 1975-88 7873 Sabinal, Tex. 1903-46, 1948-88~~

~~9265 Uvalde, Tex. 1905-85 9268 Uvalde, Tex. 1985-88~~

~~08208000 Atascosa River at Whitsett, Tex. 1932-88 4254 Hondo, Tex. 1900-75 4256 Hondo, Tex. 1975-88 9716 Whitsett, Tex. 1914-61, 1964 9717 Whitsett, Tex. 1964-88~~

082 1 0000 Nueces River near Three Rivers, Tex. 1915-88 1007 Brackettville, Tex. 1900-31, 1935-88 1486 Carrizo Springs, Tex. 1912-17, 1928-72 1975-88 2458 Dilley, Tex. 1910-87 3508 George West, Tex. 1916-88

~~Table 6 61 Table 6. Selected streamflow stations, associated precipitation stations, and periods of record in the Nueces River Basin Continued~~

~~Streamflow station number and name Precipitation station number Available periods and location of record~~

~~4254 Hondo, Tex. 1900-75 4256 Hondo, Tex. 1975-88 9265 Uvalde, Tex. 1905-85 9268 Uvalde, Tex. 1985-88~~

~~9716 Whitsett, Tex. 1914-61, 1964 9717 Whitsett, Tex. 1964-88~~

~~0821 1000 Nueces River near Mathis, Tex. 1939-88 1007 Brackettville, Tex. 1900-31, 1935-88 1486 Carrizo Springs, Tex. 1912-17, 1928-72 1975-88 2458 Dilley, Tex. 1910-87 4254 Hondo, Tex. 1900-75~~

~~4256 Hondo, Tex. 1975-88 3508 George West, Tex. 1916-88 9265 Uvalde, Tex. 1905-85 9268 Uvalde, Tex. 1985-88~~

~~9716 Whitsett, Tex. 1914-61, 1964 9717 Whitsett, Tex. 1964-88~~

~~Table 7. Long-term trends in streamflow and associated precipitation for streamflow stations in the Nueces River Basin~~

~~[no change, less than 5-percent increase or decrease for 50 years of streamflow record, or less than 3-percent increase or decrease for 50 years of precipitation record]~~

~~Long-term trend~~

~~Streamflow station number Annual Annual Associated and name Annual mean minimum maximum . . . streamflow daily mean daily mean . .. .. streamflow streamflow Precipitation~~

08190000 Nueces River increased increased decreased increased at Laguna, Tex. 08194000 Nueces River decreased increased decreased no change at Cotulla, Tex. 08195000 Frio River at increased increased decreased no change Concan, Tex.

62 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States Table 7. Long-term trends in streamflow and associated precipitation for streamflow stations in the Nueces River Basin

~~[no change, less than 5-percent increase or decrease for 50 years of streamflow record, or less than 3-percent increase or decrease for 50 years of precipitation record]~~

~~Long-term trend Streamflow station number Annual and name Annual mean minimum streamflow daily mean streamflow 5= SS~~

08198000 Sabinal River increased increased increased increased near Sabinal, Tex. 08205500 Frio River increased increased decreased increased near Derby, Tex. 08208000 Atascosa River decreased increased decreased decreased at Whitsett, Tex.

~~08210000 Nueces River near decreased increased decreased no change Three Rivers, Tex. 08211000 Nueces River decreased increased decreased increased near Mathis, Tex.~~

Table 8. Water-budget analysis for losses in annual mean streamflow resulting from filling and evaporation at Choke Canyon Reservoir [ft3/s, cubic feet per second; acre-ft, acre-feet; --, data not available or not used]

Expected Total Actual mean Streamflow Volume _. . Estimated mean upstream streamflow reduction reduction Water streamflow mean at station at station at station year at station reservoir streamflow 08210000 08210000 08210000 »? reservoir 08210000 (ft'/s) (acre-ft) (acre-ft) (acre-ft)3

~~1965 661 __ 749 _ _ __ 1966 495 ~ 564 ~ ~ ._ 1967 1,456 ~ 2,040 ~ _. 1968 865 - 1,132 ~ - ..~~

~~1969 112 140 ._ 1970 766 « 843 ~ ~ .. 1971 2,286 2,110 ~ .. 1972 1,566 ~ 1,680 - ~ ~~~

~~1973 807 689 ._ 1974 1,251 1,213 ~ ~ 1975 719 668 ~ 1976 695 681~~

~~Table 8 63 Table 8. Water-budget analysis for losses in annual mean streamflow resulting from filling and evaporation at Choke Canyon Reservoir Continued~~

Expected Total Actual mean Streamflow Volume Estimated mean Change in upstream streamflow reduction reduction evaporation Water streamflow storage at mean at station at station at station from the year at station reservoir streamflow 08210000 08210000 08210000 reservoir 08210000 (acre-ft)2 (ft3/s) (ftS/s) 1 (ftVs) (ft3/*) (acre-ft) (acre-ft)3

~~1977 1,424 __ 1,586 __ 1978 349 - 441 ~ ~ 1979 573 511 ~ 1980 673 ~ 877 ~ - ~ ~~~

~~1981 1,269 1,237 ~ 1982 506 487 ~ ~ ~ 1983 170 182 202 ~ ~ 1984 37 40 82 ~ ~ +4,000 2,000~~

~~1985 708 758 566 192 139,000 +99,000 15,000 1986 559 598 448 150 109,000 +111,000 37,000 1987 1,908 2,042 1,244 798 578,000 +479,000 50,000 1988 194 208 120 88 64,000 -33,000 98,000~~

1989 49 52 268 -216 -156,000 -262,000 119,000 1990 684 732 646 86 62,000 +24,000 63,000 TOTALS4 796,000 +422,000 384,000 1 The total 1965-82 streamflow at the four streamflow stations upstream from station 08210000 was 93 percent of the total streamflow at station 08210000. The long-term streamflow at station 08210000, prior to the construction of Choke Canyon Reservoir, was assumed to be 1.07 times greater than the total streamflow at the upstream four stations. 2 Difference between storage in reservoir from beginning to end of year (data from USGS). 3 Evaporation as calculated based on pan-evaporation data from the reservoir (U.S. Department of Congress, 1889-1989) and pan- evaporation coefficients (Kane 1967). 4 The total estimated volume reduction at station 08210000 from October 1984 through September 1990 is 796,000 acre-ft. The total change in storage at the reservoir, 422,000 acre-ft, represents the volume impounded at the end of the 1990 water year. The sum of the total change in storage and total estimated net evaporation represents 806,000 acre-ft, which approximates the total estimated streamflow reduction of 796,000 acre-ft.

~~64 Streamflow Analysis of the Apalachicola, Pearl, Trinity, and Nueces River Basins, Southeastern United States~~