Magnitude and Frequency of Low Flows in the Suwannee River Water Management District, Florida
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Magnitude and Frequency of Low Flows in the Suwannee River Water Management District, Florida By G.L. Giese and M.A. Franklin U.S. GEOLOGICAL SURVEY Water-Resources Investigations Report 96-4308 Prepared in cooperation with the SUWANNEE RIVER WATER MANAGEMENT DISTRICT Tallahassee, Florida 1996 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 in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey. For additional information write to: Copies of this report can be purchased from: District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Center 227 North Bronough Street, Suite 3015 Box 25286 Tallahassee, Florida 32301 Denver, CO 80225-0425 CONTENTS Abstract ................................................................................................................................................................................. 1 Introduction .......................................................................................................................................................................... 3 Purpose and Scope ...................................................................................................................................................... 5 Previous Studies ......................................................................................................................................................... 6 Acknowledgments ....................................................................................................................................................... 6 Statistics Used in This Report .............................................................................................................................................. 7 Factors Affecting Low-Flow Characteristics of Streams ..................................................................................................... 9 Low-Flow Frequency Analysis ............................................................................................................................................ 12 Low-Flow Synoptic Surveys ................................................................................................................................................ 16 Summary ............................................................................................................................................................................... 18 References ............................................................................................................................................................................ 20 Appendix I. Magnitude and frequency of low flows for gaging stations in the Suwannee River Water Management District, Florida ................................................................................................................................. 24 Appendix II. Synoptic low-flow measurements for low-flow partial-record stations and miscellaneous sites in the Suwannee River Water Management District, Florida, 1990-96 ............................................................................ 57 FIGURES 1. Map showing location of Suwannee River Water Management District and stream-gaging stations used for estimating low-flow frequency statistics ................................................................................................................. 4 2. Map showing physiographic regions within the SRWMD..................................................................................... 10 3. Graph showing low-flow frequency curves of the annual lowest 1- and 30-consecutive-day periods for station 02321500, Santa Fe River at Worthington Springs ..................................................................................... 13 4. Graph showing discharge relation used to estimate selected low-flow characteristics at partial-record station Olustee Creek near Lulu from low-flow characteristics at index station Santa Fe River at Worthington Springs................................................................................................................................................ 14 5. Location of low-flow synoptic measurement sites in the Suwannee River Water Management District ............... 16 Contents III Magnitude and Frequency of Low Flows in the Suwannee River Water Management District, Florida By G.L. Giese and M.A. Franklin Abstract in springs downstream from a gage. Many of the smaller streams in the District go dry or have no flow Low-flow frequency statistics for 20 gaging sta- for several months in many years. tions having at least 10 years of continuous record and In addition to the low-flow statistics, four syn- 31 other stations having less than 10 years of continu- optic low-flow measurement surveys were conducted ous record or a series of at least two low-flow mea- on 161 sites during 1990, 1995, and 1996. The mea- surements are presented for unregulated streams in the surements were made to provide “snapshots” of flow Suwannee River Water Management District in north- conditions of streams throughout the Suwannee River central Florida. Statistics for the 20 continuous-record Water Management District. Magnitudes of low flows stations included are the annual and monthly mini- during the 1990 series of measurements were in the mum consecutive-day average low-flow magnitudes range associated with minimum 7-consecutive-day 50- for 1, 3, 7, 14, and 30 consecutive days for recurrence year recurrence interval to the minimum 7-consecu- intervals of 2, 5, 10, 20, and, for some long-term sta- tive-day 20-year recurrence interval, except in Taylor tions, 50 years, based on records available through the and Dixie Counties, where the magnitudes ranged 1994 climatic year. Only the annual statistics are from the minimum 7-consecutive-day 5-year flow given for the 31 other stations; these are for the 7- and level to the 7-consecutive-day 2-year flow level. The 30-consecutive day periods only and for recurrence magnitudes were all greater than the minimum 7-con- intervals of 2 and 10 years only. Annual low-flow fre- secutive-day 2-year flow level during 1995 and 1996. quency statistics range from zero for many small Observations of no flow were recorded at many of the streams to 5,500 cubic feet per second for the annual sites for all four series of measurements. 30-consecutive-day average flow with a recurrence interval of 2 years for the Suwannee River near Wil- cox (station 02323500). Monthly low-flow frequency INTRODUCTION statistics range from zero for many small streams to 13,800 cubic feet per second for the minimum 30-con- In recent years there has developed a better secutive-day average flow with a 2-year recurrence awareness that natural systems such as wetlands, flood interval for the month of March for the same station. plains, native ecological communities, and aquifer Generally, low-flow characteristics of streams in recharge areas within the 7,640-square-mile SRWMD the Suwannee River Water Management District are (Suwannee River Water Management District) (fig.1) controlled by climatic, topographic, and geologic fac- provide vital water-related functions. These functions tors. The carbonate Floridan aquifer system underlies, include water-quality treatment, water supply, flood or is at the surface of, the entire District. The terrane’s water conveyance and attenuation, fish and wildlife karstic nature results in many sinkholes and springs. In habitat, and recreational and economic values. These some places, springs may contribute greatly to low systems depend on the maintenance of the natural streamflow and the contributing areas of such springs variability of the hydrologic cycle as reflected by the may include areas outside the presumed surface drain- magnitude, duration, and timing of changing stream- age area of the springs. In other places, water may flow, rising and falling water levels of lakes, rivers, enter sinkholes within a drainage basin, then reappear and aquifers, and interaction of surface and ground Introduction 1 84°00′ 83°30′83°00′ 82°30′ 82°00′ GEORGIA 02326250 30°30′ 02317620 02319000 02314986 02317630 02326389 02315000 r 302547083043700 e 02326391 02315550 iv R 02315542 02315200 a 02319500 02326529 l 02326500 l i 02315532 c 02315392 u A 02315500 02326526 02325950 02319800 r 301929082464400 02326512 Rive 30202508248400 a n Lake i f 02326000 Suw City n 02324400 a 02321600 02321700 30°00′ o w nn c llo ay River e E o e 02322660 h 02320000 n R e iv F e 02321800 02321200 r 02321000 02325500 r e ta 02321500 v 02320500 n 02320732 i a S F R e r 02322800 ve 02320800 e Ri e 02322590 02321898 h 02320700 c 02322500 t 02324000 02322000 a h n i 02322016 e 02323000 S t G U 29°30′ L F r O e 02323500 v F i R r e M e v e i 02313448 E n n R X a w a I Su s C s 02313522 a O s a c c a W 0 20 40 MILES 29°00′ 0 20 40 KILOMETERS 02314200 EXPLANATION SUWANNEE RIVER WATER FLORIDA MANAGEMENT DISTRICT LOCATION OF BOUNDARY SUWANNEE RIVER WATER MANAGEMENT 02314200 STREAM-GAGING STATION—And number DISTRICT 02314134 LOW-FLOW PARTIAL-RECORD STATION—And number 02321446 MISCELLANEOUS SITE—And number Figure 1. Location of Suwannee River Water Management District and stream-gaging stations used for estimating low-flow frequency statistics. waters. Human activities cause alterations to the natu- must be better understood to establish minimum flow ral hydrologic regime and may have adverse impacts and