S TORAG E REQUIREMENTS FOR GEORGIA STREAMS U.S. GEOLOGICAL SURVEY WAT ER RESOURCES INVESTIGATIONS Open-File Report 82-557 Prepared in cooperation with the GE O R G I A DEPA R TMENT OF" NATURAL RESOURCES STORAGE REQUIREMENTS FOR GEORGIA STREAMS By R. F. Carter U.S. GEOLOGICAL SURVEY Water Resources Investigations Open-File Report 82-557 Prepared in cooperation with the GEORGIA DEPARTMENT OF NATURAL RESOURCES Doraville, Georgia 1983 CONTENTS Page Abstract 1 Introduction............................................................. 1 Purpose and scope 2 Cooperation and acknowledgments 2 Methods of analysis...................................................... 3 Within-year storage 3 Over-year storage................................................... 5 The combined draft-storage relation................................. 5 Regionalization of draft-storage relations 7 Presentation of draft-storage data....................................... 9 Accuracy.. . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Adjustment for natural storage depletion 30 Application to stream-development problems............................... 34 Determination of storage required at potential reservoir sites...... 34 General utility of the data 37 Summary.................................................................. 38 Selected references 39 ILLUSTRATIONS Page Plate 1. Map of Georgia showing average annual runoff, draft-storage regions, and location of gaging stations. in pocket Figure 1. Draft-storage-frequency diagram for Flint River near Culloden (station 02347500) 6 2. Draft-storage diagram for 20-year recurrence interval for Flint River near Culloden (station 02347500) 7 3. Draft-storage diagram for selected frequencies for Flint River near Culloden (station 02347500) 8 4. Graphs showing draft-storage relations for selected frequencies related to the 10-year recurrence interval, 7-day average flow for streams in Region A: a. 2-year frequency graph 10 b. 5-year frequency graph 11 c. 10-year frequency graph 12 d. 20-year frequency graph 13 e. 30-year frequency graph 14 5. Graphs showing draft-storage relations for selected frequencies related to the 10-year recurrence interval, 7-day average flow for streams in Region B: a. 2-year frequency graph 15 b. 5-year frequency graph 16 c. 10-year frequency graph 17 d. 20-year frequency graph 18 e. 30-year frequency graph 19 iii FACTORS FOR CONVERTING INCH-POUND UNITS TO INTERNATIONAL SYSTEM (SI) UNITS The analyses and compilations in this report were made with inch-pound units of measurement. To convert inch-pound units to metric units, the following conversion factors should be used: Multiply By acre-foot (acre-ft) 1233 cubic foot per second (ft3/s) 0.02832 inch (in.) 2.540 mile (mi) 1.609 million gallons per day (Mgal/d) 3786 square mile (mi2) .. ~ 2.590 To obtain cubic meter (m3) cubic meter per second (m3/s) centimeter (em) kilometer (km) cubic meters per day (3/d) square kilometer (km2) v STORAGE REQUIREMENTS FOR GEORGIA STREAMS By Robert F. Carter ABSTRACT The suitability of a stream as a source of water supply or for waste disposal may be severely limited by low flow during certain periods. A water user may be forced to provide storage facilities to supplement the natural flow if the low flow is insufficient for his needs. This report provides data for evaluating the feasibility of augmenting low streamflow by means of storage facilities. It contains tabular data on storage requirements for draft rates that are as much as 60 percent of the mean annual flow at 99 continuous-record gaging stations, and draft-storage diagrams for estimating storage requirements at many additional sites. Through analyses of streamflow data, the State was divided into four regions. Draft-storage diagrams for each region provide a means of estimating storage requirements for sites on streams where data are scant, provided the drainage area, mean annual flow, and the 7-day, 10-year low flow are known or can be estimated. These data are tabulated for the 99 gaging stations used in the analyses and for 102 partial-record sites where only base-flow measurements have been made. The draft-storage diagrams are useful not only for estimating in-channel storage required for low-flow augmentation, but also can be used for estimating the volume of off-channel storage required to retain wastewater during low-flow periods for later release. In addition, these relationships can be helpful in estimating the volume of wastewater to be disposed of. by spraying on land, provided that the water disposed of in this manner is only that for which streamflow dilution water is not currently available. Mean annual flow can be determined for any stream within the State by using the runoff map in this report. Low-flow indices can be estimated by several methods, including correlation of baseflow measurements with concurrent flow at nearby continuous-record gaging stations where low-flow indices have been determined. INTRODUCTION The climate of Georgia is humid. Precipitation averages about 50 inches per year, and on the average, 15 inches of this precipitation appears as stream runoff, an amount equal to 64,000 Mgal/d. About 1,230 Mgal/d of this amount, less than 2 percent, is put to use by man, excluding such categories of use as navigation and electric-power generation. Based on this rate of runoff, it seems that the available supply should be adequate for the demand, but seasonal low flows limit the dependable year-round surfacewater supply unless storage is provided. Demands for very large volumes of water for navigation and electricpower generation are commonly met by construction of large reservoirs on major rivers. These rivers are not conveniently located to supply the needs of many water-using facilities distributed irregularly over large areas. Many surface-water users rely on smaller tributary streams and limit their rate of use to low flow during drought or they consider augmenting their supply from storage. Development of such storage facilities may require use of ungaged streams. 1 }lliTHODS OF ANALYSIS An analysis of storage requirements to insure dependable draft rates requires data on streamflow characteristics. Ideally, a long-term record of daily flows should be available at the potential damsite. Unfortunately, this ideal situation is seldom realized. In this report, draft-storage relations have been developed at points on streams where continuous records of streamflow are available, and these relations have been regionalized to estimate storage requirements on streams where information is scant. Regionalized storage-requirement curves were first published for Georgia streams by Thomson and Carter (1963). Those curves were based on mass curves of streamflow during the drought of 1954 and, hence, were applicable only to a drought period such as that of 1954. Some later storage studies (Carter and Gannon, 1965) were more generally applicable, but were for limited areas. The present study is aimed at delineating storage requirements throughout the State for optimum development of available streamflow. Long periods of streamflow record are analyzed and the probabilities of given amounts of storage being deficient are evaluated. For convenience, separate analyses were made of within-year and overyear storage requirements, accordirig to the time required for replenishment. Within-year storage was analyzed by use of a computer program which, in effect, constructed a mass curve of streamflow for each year of the record and computed yearly storage requirements for various draft rates. These storage data were analyzed on a frequency basis by statistical methods. For droughts having recurrence intervals greater than 5 years, over-year storage must be considered for draft rates that exceed 40 to 80 percent of the mean annual discharge over most of the State (Regions A, B, and C, pl. 1), and for draft rates that exceed 20 to 40 percent of the mean annual discharge in the remainder of the State (Region D, pl. 1). The analysis of over-year storage is based on probability routing of mean annual discharge to define storage requirement related to the mean annual discharge and the variability of the annual discharges (Riggs and Hardison, 1973). Both analyses are explained in more detail in the following sections. Within-Year Storage Draft-storage analyses for each year of record were prepared for all continuous-record gaging stations used in this report. The analyses were based on data for the climatic year (beginning Apr. 1), because a reservoir would most likely be full on that date. Data for the analyses were prepared by use of the U.S. Geological Survey ANSTOR computer program. In general, draft-storage relations were computed at gaging stations on streams having continuous discharge records of 8 years or more and not materially affected by regulation. Most of the large streams are regulated to some . extent; therefore, only streams having drainage areas of about 2,000 mi2 or less above the gaged site and not subject to significant regulation were used in the analyses. The program assumes a full reservoir on April 1 and for each of several selected draft rates computes the annual maximum depletions, which are the storage requirements. The computer performs the analyses arithmetically rather than graphically. Table 1 shows a typical output of this program, for the gaging station, Flint River near Culloden, Ga. 3 Frequency curves (fig. 1) of storage required to maintain draft rates of 150, 200, 260, 320, 380, 440, 520, 600, 700, and 900 ft3/s were prepared from the data in table 1. Storage quantities were arrayed in order of magnitude and assigned order numbers with the largest magnitude as 1. The recurrence intlrval (RI) of each value in the array was computed by the for- mula RI = ~' where N is the number of years (51 in this example) in the array and H is the order number. Storage quantities were plotted against the appropriate recurrence interval on extreme log-data graph paper and lines of best fit were drawn through the points. The extreme log-data form used has the abscissa graduated according to the Gumbel Type I extremal distribution and the ordinate scale is graduated logarithmically. The resulting graph paper is commonly referred to as Weibull probability paper (Chow, 1964). By using this method, frequency curves of within-year storage requirements at 99 sites were computed at various draft rates. Only gaging stations having at least 8 years of record were included in the analyses. The following limits were established for extending frequency curves. (1) For stations at which 8 or 9 years of record were available, the frequency curves were extended to the 10-year recurrence interval. (2) Stations having 10 or more years of record, but less than 20 years, were extended to 20 years. (3) Stations having 20 or more years of record were extended to 30 years. Within these limits, draft-frequency data were read from the curves for recurrence intervals of 2, 5, 10, 20, and 30 years. The example computation for Flint River near Culloden was extended to 50 years to help illustrate the method of using frequency curves. Over-Year Storage Over-year storage will be required to maintain high draft rates. The method for analyzing over-year storage, as described by Riggs and Hardison (1973), is used in this report. This method is based on probability routing of annual mean discharges to define storage requirements. Diagrams in that report show storage requirements in terms of draft rate and variability of annual mean flows. Because these diagrams are based on an assumption of a constant flow during each year, seasonal adjustments, as described by Riggs and Hardison (1973), were made to draft-storage relations computed from them (fig. 2). The Combined Draft-Storage Relation Curves showing the relation of draft rates of as much as 60 percent of the mean annual discharge to storage requirements were obtained by combining over-year storage curves and within-year storage curves computed from ANSTOR computer data. A draft-storage curve for Flint River near Culloden for a 20-year recurrence interval (fig. 2) illustrates the method of combining the two. Figure 3 shows draft-storage relations for 2-, 5-, 10-, 20-, and 30year frequencies for Flint River near Culloden. For a 20-year recurrence interval, over-year storage is required for streams in Georgia when the draft rate exceeds from 30 to 50 percent of the mean annual discharge. 5 24oo.--------.---------.--------.--------.---------r--------~------~ 2000 0 z 0 0 UJ C/) 0: 1600 UJ c... IUJ UJ lL 0 1200 en ::::::> 0 ;;t - UJ I- 800 <( 0: IlL <( 0: 0 400 Seaso na l a dju s tment EXP L ANAT I O N !:::. W ITHI N-YEAR S TO R AGE 0 OVER-YEAR STORAGE 0 S EA SO NAL ADJUSTMENT TO BE ADDED TO OVER - YEAR S T ORAGE TO T AL ST ORAG E REQU I RED 0~-------~~------~---------L---------L--------~--------~------~ 0 400 800 1200 1600 2000 2400 2800 STORAGE REQUIRED, IN THOUSANDS OF ACRE-FEET Figure 2.- Draft-storage diagram for 20-year recurrence interval for Flint River near Culloden (station 02347500), showing method of combining within-year and over-year storage curves. Regionalization of Draft-Storage Relations Draft-storage relations at other than gaged sites can be estimated by relating draft-storage data to some flow parameter that can be estimated at the ungaged site. Draft-storage relations computed from streamflow records tend to have similar areal characteristics and patterns and lend themselves to definition of regional families of storage curves when compared with a third parameter, such as a characteristic of low flow. The selection of a low-flow index is not critical and, for this report, the index used is the minimum average flow for 7 consecutive days with a 10-year recurrence interval (7Ql0). To eliminate the effect of stream size, the data need to be converted to ratios to drainage-area size or to ratios to magnitudes of mean annual f low or storage. Regional storage curves previously published for Georgia streams used flow and storage data in units of ratio to drainage area. However, the magnitude of mean annual flow is a factor affecting draft-storage relations, especially for the higher draft rates. Tests of the two methods of adjusting for stream size showed that more consistent 7 errors of estimate. These regions conform, in part, to physiographic provinces. The need for such subdivision was first noted during preparation of regional storage curves based on the 1954 drought. Actual locations and boundaries of the regions in this report were mainly dictated by general patterns of draft-sto~age relationships. Region A conforms closely to the Valley ahd Ridge physiographic province in the northwest. Region B includes the remainder of the area north of the Fall Line, the Blue Ridge and the Piedmont provinces. The Coastal Plain, the area south of the Fall Line, is subdivided into Regions C and D. PRESENTATION OF DRAFT-STORAGE DATA Drainage areas, mean annual discharges, 7-day,10-year low flows, and locations by region are listed in table 2 for 99 continuous-record gaging stations and for 102 partial-record gaging stations. Low-flow data (7-day, 10-year) shown in table 2 were taken from the report by Carter and Putnam (1977). Draft-storage relations for th~ 99 continuous-record stations are listed in table 3 up to draft rates as much as 60 percent of the mean annual flow. High values of draft and storage are not shown for many streams in Regions C and D in the south, because the flat terrain limits availability of favorable sites for large reservoirs. Because of their length, tables 2 and 3 are placed at the end of the report. Eleven of the gaging stations listed in table 3 were moved to near the end of the table to allow better definition of their draft-storage relations. This was done because they are in mountainous areas and have a regimen of flow that is greater, per unit of drainage area, than the State average. If these gaging stations had not been handled in this manner, table 3 would have been required to contain a greater number of columns, many of which would have been blank for most gaging stations. Families of draft-storage curves are presented for each of the four regions for use in estimating storage requirements for ungaged streams. These curves are shown in figures 4-7 with 2-, 5-, 10-, 20-, and 30-year recurrence intervals shown as a, b, c, d, and e, respectively, for each figure number. These plots define the storage required for draft rates as much as 60 percent of the mean annual discharge. Definition of the curves is illustrated by plots of gaging-station data for a storage of 7 percent of the mean annual runoff for a 10-year frequency of recurrence in Region B (fig. 5c). The method for using the curves is- explained in the section, "Application to Stream-Development Problems." Draft rates and storage data in table 3 are expressed as ratios to the drainage area of each gaging station instead of as ratio to mean, as in figures 4-7. It was felt that use of only one multiplier (drainage area) in table 3 for figures in the column headings (draft rates) and for figures in the body of the report (storage volumes) would make the table easier to use and would help to prevent errors. If the data in this table were expressed in units of ratio to mean, then two multipliers would be necessary. Mean annual flow would be needed for draft rates and mean annual flow volume would be needed for storage values, and this could possibly cause confusion. 9 0.6 0.5 0.4 1 0.3 5= 0 ....J LL 0.2 ....J <{ i :z:J z <{ I z <{ w 0. 1 ~ 0. 0 9 0 0. 08 f- 0 0. 07 f- 0. 06 <{ a: z 0. 0 5 w- 0. 04 f- <{ a: I f- 0.03 1 - - LL <{ a: 0 0. 0 2 0. 1 0 .0 7 0.05 0 .0 3 0 0.3 0 . 1 ;,j!C--+--+ -..~ ----.- - . - - . j - - - - - - - - l ------+-------~ 0.09 0.03 0.0 1 0.0 1 Figure 4b . - Draft- s torage relations for 5-year frequency related to the 10- year recurrence interval , 7-day average flow for streams in region A. Relations shown are for uniform draft rates. No adjustment has been made for reservoir seepage and evaporation. 11 0.6r 0.5 - -- ---+ 411------- 0 . I --+---------+-11 0.3 r-----------+--o~.~1 --~-=-+---r--r--r~~=r-+--=~~ ~ 0 I 0.07 _J ll.. 0. 2 1 - - - - - - - - - 1 - - - - + - - ---=-"'"""t _J 0. 0 5 <( ~ z z I <( z <( w ~ 0 f- o o. o7 r--- - - --------o:nT ~ 0 . 0 6 1-----------+1,--"0-'-.-'-0-"0-"--7' -+-------7"~-/- 0.05 Figure 4d.- Draft-storage relations for 20-year frequency related to the 10-year recurrence interval, 7-day average flow for streams in region A. Relations shown are for uniform draft rates. No adjustment has been made for reservoir seepage and evaporation. 13 ~ 0 __/ LL __/ <( 0.6 r---------.-----r---.--.--r-.-~-.---------.----~------~~=-~~~=-~~--~~~~~ 0.6 0.5 L= 0.4 0. 1 0.5 i . ......7. '"'f-----!l 0 . 4 ~ II o. 0.3 0 .0 7 I 3 :::::> 0 .0 5 l z z <( 0.2 0 .0 3 0 .0 2 ! ~~~~~~~q_-b~4--L-~~----+---~~~I 0.2 z <( 0.0 1 w :::2: 0 1- 0 1- <( L= 0. 1 0. 09 I~-------4~-~~~--~~ + -~ ='-"'-"""+T'- -s-~ ' - -~ + --+-------- ------ -~+------4l --- -- --:...4..r:~ -- - +q-_- +--+--++- +--++~- ++---~- --- ----" ----- --- +- --1-- --- ---++-- ----- --- !!! 0.1 0 . 0 9 0. 08 ~-++---------+---~~ +--+---4--+--+-+4---.-- -------+----~-~1 0.08 0. 0 7 --~~~---+--~~-+-+-~h-~-----+----4-~ 0.07 -V1 a: 0. 06 z w- 0. 0 5 1- 0. 0 4 -+~-4-+-+-+-------~~--4---+--+-4-4-+-~+-~------+----4-~1 0.06 ____, _ I <( a: 1- 0. 03 LL <( a: -r-rI .......~--)- -- - - I 0 I II , 0 0.0 2 0. 0 1 0 . 001 0 . 01 0.1 0 .123 0.4 TEN-YEAR MINIMUM 7-DAY AVERAGE FLOW , IN RATIO TO MEAN ANNUAL FLOW Figure Sa . - Draft-storage relations for 2-year frequency related to the 10-year recurrence interval , ?-day average flow for streams in region B. Relations shown are for uniform draft rates. No adjustment has been made for reservoir s eepage and evaporation. Computation of storage requirement for a stream site with a low-flow inde x of 0.123 mean annual flow is illustrated a s e x plained in "Determination of Storage Required at Pontential Reservo i r Sites " . 0.6 s 0.5 I~-- 0 . 2 0 0.4 _J LL _J -< I 0.3 ~---- ::J z z -< I 0 . 2 Ir z -w< ::2: -t 0.1 I r-~ I 0 .0 7 0.0 5 0.03 0 I- 0. 1 0. 09 ~ 0 I 0. 08 I- -< 0. 0 7 a: 0. 06 z '-"..".."J . 0.05 w I- 0. 0 4 -< a: I I- 0. 0 3 LL -< a: 0 0.02 ' 0.3 0. 03 0. 0 1 0. 001 0 . 01 0.1 0 .123 0.4 TEN-YEAR MINIMUM 7-DAY AVERAGE FLOW , IN RATIO TO MEAN ANNUAL FLOW Figure 5c.- Draft-storage relations for 10-year frequency related to the 10-year recurrence interval. 7-day average flow for streams in region B. Relations shown are for uniform draft rates. No adjustment has been made for reservoir seepage and evaporation . Definition of curves is illustrated by plotting of data points for the curve representing 0.07 mean annual flow volume. Computation of storage requirement for a stream site with a low-flow inde x of 0 .123 mean annual flow is illustrated as explained in "Determination of Storage Required at Potential Reservoir Sites" . 0.6 s: 0.5 0 0.4 _.J LL _.J 0. 3 <( :) z z <( 0.2 z <( w 2 0 I- 0 I- <( a: ..... z \0 w - I- <( a: I- 0 . 0 3 LL <( a: 0 0. 0 2 I0.3 -l 0 . 2 0.01 0.1 0 .12 3 0.4 TEN-YEAR MINIMUM 7-DAY AVERAGE FLOW , IN RATIO TO MEAN ANNUAL FLOW Figure 5e.- Draft-storage relations for 30-year frequency related to the 10-year recurrence interval , ?-day average flow for streams in region B. Relations shown are for uniform dr a ft rates . No adjustment has been made for reservoir s eepage and evaporation . Computation of storage requirement for a stream site with a low - flow inde x of 0.123 me a n annual flow is illu s trated a s e x plained i n "Determin a tion of Stor a ge R e quired a t Pontential Reservoir Site s. 0.2 0 . 6 ,-------------,. 0 . 6 ~.,.,.r-_,.~.,..,~..,-,,.~,-~ -~~""'----~~-"S~~~o9'~:A--+--l 0. 5 0 . 1 stor ~ 0.3 r-------------+-----~------~--~ ---+--~~ .~----~~- ---.'~~~~7~ --~----r--~!--~-~ 0.3 0 _J .0 7 Li.. _ 0.5 0.4 0.2 0. 1 r---------+---~~~~~~~~~-4~~-------~------r---+-~--+-~ 0 . 09 r---~~~~--~~~~~~-+~~-4---------~------r---+-~~-+-~ 0.08 0 . 0 1 ,____ ______ 0 . 01 lllJ .I 1 I . I, . I! c REGION i I ---'------LII. J l I 1 I 20- Year frequenc_y l lI _____jI__ _L!___ _l___,___, o. o1 0.1 0.7 TEN-YEAR MINIMUM ?-DAY AVERAGE FLOW, IN RATIO TO MEAN ANNUAL FLOW Figure 6d.- Draft-storage relations for 20-year frequency related to the 10-year recurrence interval , ?-day average flow for streams in region C . Relations shown are for uniform draft rates. No adjustment has been made for reservoir seepage and evaporation . 23 s 0 _) [ : ' lL : _) <( i !' I : i 0. 1 z ~ z 0. 09 0. 0 8 i 0. 07 <( ; i 0. 06 z <( w : ' 0. 0 5 i 0.04 2 ! . N V1 0 1- 0 . 03 I I i ' J.t.. 0 0. 0 2 I I t i : i I ' I II I 0. 0 3 i I I i I 0. 0 2 1- L-l-+-~t"ttf:!~ f ~ : ~I ;fi : <( a: z ' i ! ! i I II : ' l ' I II i: !i. ' 0 . 01 0.009 ~----~---~~~-+~~~-----~--~--!--~~++----_,--/~~~~-i -~I' ~~+4~------ -~ -- -- -~ -- -+ ~- ~+ 4~ -- 4i f -i- ~J ~,'~ H 0 . 01 0.009 i-++++H w-------+---+--i---+ 1- 0.008 0o..0o0o76 <( a: 0 .0 0 5 i i! I I " i,;' i : _/ 7 ~---L--'-+++--- ~"---: I j ..-"" J I II I ; .. LI ..ll--r-t-+-~-----'---- ! lltttl 0.008 0o.. 0o0o76 I ' I i I i I II i 0 00 . 5 1- lL ~ ~ ~: ~-+.-..i.,-. -y'--ir--: 1-----+--+1-._l !---+~-'~- I ~: ~ ~: <( _ f------+i--+f-..--+-+-+-++1 +' +, - - - i-il - I -1 + H-+---- j I i.,-..-=.o.-:-..-.+,~.-.-~1--+-1-li-+i-+~- ~: ~~~ ~ ~~~~~~ f~e~u~n!c~ ~ a: 0 0. 0 0 2 1----+jl-i---+1-1+1-----il-:l"-t-.--+lj-_+_-+..+...i.+f/j-.+-; l-i-1-+---T+-1:--+---+-1 ! ! 0. 0 0 2 0.00 1,L-----r- i I I I II I I I I. i I ., I I I II 0 . 0 0 1 0.00001 0 .0001 0.001 0 .01 0.1 TEN-YEAR MINIMUM 7-DAY AVERAGE FLOW , IN RATIO TO MEAN ANNUAL FLOW Figure 7a.- Draft-storage relations for 2-year frequency related to the 10-year recurrence interval, 7-day average flow for streams in region D. Relations shown are for uniform draft rate s . No adjustment has been made for reservoir seepage and evaporation. 0.6 L-r-----r--~~~~~~----~-------,--rl-~l~~--r----~--~~~---~-~-,-r~----~~-,----,--~~~~ 0.6 0 . 5 I ! I I l : --+ --+~ ---+----+--'--+---1 0 . 5 0. 4 1 0.3 1 I i i l i I I l I !: :+-n 0.4 : 0.3 .N...... ~ l ' I !...; .. 0 0.2 i _J lL ! : I ' _:..- 0.2 _J 'i ,l ::: - ~ <( 01 1 i ,, : : 01 o I r I .w- .- ,- ~;:;; , . 8: 8~ :zJ o. 9 8:89 z I t <( 0 06 J ! +--L I 1 I l , -t i I J: v~A .--, -- ~ _..i....-t"" I . I - ! . .......---- ~~/. /' ;:;.."...._ r:-Lh/i 0 .0 7 ;1 0.06 i z 0.05 1 : l _,,j , ; ' ~I- , I ;i ......,.--:---,-.1; .......~ --------_.);;' . /_1 / ~/ / /./.!/ I ' 005 <( w ~ Lf !I! _ ~ n-~:, ~ ~::('--:},1V 2 o.o4 i 5 r eqy ir e~, i h -~~~dld me a n ~ t_::::::I:_..,~J..J-...1 rU_-J )~ ,-/~//1/ 0 0 03 ! s torage f- I ; ; :/ 't 0 0.02 j f<( i ' ; ! a: ,1 z w - f<( 0.0 1 0.009 0 0 08 ~- > i,. 00 ..000076 t--- - -+-------it---+--+--+- ' : a: 5 _c 1 1 a'iJ nu aTLfloiv vjotcrnte i, I I_ : . 'II,~ ~ ~~ ~ - ~/: i il' ~ i M"~ : / 'I ~- I I' ' - I -- 1 ! ' ..;....;-1~.,. o .oo 3 oo <<)-- o. ! ~ :_ . ~ ~ ;- lIi i'.I_ 1!I !1Ii 1iI J I . , (\ - _ _ . . .:-, -- - - -. -.----: ! 'I .... - U ;,.;;;..- , J / I ; I 1/ ~==t:;;;~:t:Enn====~=:rnrtt==1=1=l:2c!~trrr=-=-=-=-=-:=-=-=-r=--~-~----~-~--_J~-++,- f- 0o.o0 0o4 ~ . I/ , 1 1 ,: o:o4 1: 0 03 :,, 0.02 ' 1 J 0.0 1 0.009 I i , 'l I :>' 'I j ,_ 000 ..000000768 1 , . 0 005 : :,-:1:1 I: . 0. 0 0 4 lL <( I / ! II I 1 I a: 0 :: : : : r--------i---+-----+--+-+-+-+-H-----+----+---+--t-1,-+1--+'-t- Ii 1 oAI / 1 1 1 I d 11 i --->-------!-!I--+1-+---ilf-+-il-!-+-1 ::::: I ! :,. REGION I ' I' 0 1 0 0 .0 0 1 '----'------'----- --'---'---'---'--'----'----'---'-----'---'-j-'--l----'--'-1L/L,__-'--ii_---'---I--'---'-/_.___/'--Jilj'-'-j__._____-_v__e,__a;_r_J_If_r_jj___q _],_eL:UlJ o.oo1 0.00001 0.001 0.01 0. 1 AVERAGE FLOW, IN RATIO TO MEAN ANNUAL FLOW Figure 7c.- Draft-storage relations for 10-year frequency related to the 10-year recurrence interval, 7-day average flow for streams in region D. Relations shown are for uniform draft rates. No adjustment has been made for reservoir seepage and evaporation. s 0 _J LL _J s: (f) ~ LL 0 <{ _J a: LL 0.0 1 0 _J _J <{ z 0 Ci w <{ :zz:J <{ z .w...... a: <{ w ::;;: ::;;: 0a: 0 0.001 0 LL f-- 0 0 w f-::J a_ f-<{ a: ... ::;;: z 0 0 w (:J <{ a: 0 f-- ~ 0.0001 Curve I- Draft r ate 1 percent of mean annual flow (f) 0 0001 SCALE FOR CURVE l i 0 001 0 01 /~.:;,.,:... "'' 0 percent of mea n annual flo w / 0 1 "'"']J[ """ "" 20 perc ent of mean annua l flo w 0 001 S,CALE FOR CURVE Il[ 0 01 0 1 05 C urve Til- D r af t rate 40 percent of / mean annual flow 0.00001L-~~~------~~~--------~~----------L---------~~----------~~--------~~-----------L------------L-----------~------__J 0.000 1 0.001 0.01 0.0001 0.001 0.01 0.1 SCALE FOR CURVE I SCALE FOR CURVE ]J[ STORAGE COM PUTED FROM GAGING-STATION DATA, IN RATIO TO MEAN ANNUAL FLOW VOLUME Figure 8.- Relation between s torage --.:~~;-.~- require me n 'f~"'' 9.0 m p u ted f r om . . gag 1n g - s t a t 1on data and from regional draft-storage diagrams for variou s d r a f t r a t e s"'.;to..r a 2 0- yea r f r e q u e n c y . EXP LAN AI I ON LIN E OF EQ UAL AVERAGE ANNUAL LA KE E VAPORAT I ON- Int e rv a l 2 in c h es EXPLANAT I O N -7 2- LINE 0 F E 0 U A L M E AN A NNU AL PREC I P I TAT I O N1 94 1 -7 0 -Int e r va l 4 in c hes w w Figure 10.- Average annual lake evaporation for the period 1946-55. From National Weather Service ( 1959). 0 I I I I I I 0 50 I I I I 50 I 00 100 I KILOMETERS Figure 11.- Average annual rainfall in Georgia , 1941-70 . (Data furnished and map reviewed by National Weather Service.) gaging stations shows a good correlation (fig. 12). The continuousrecord station used is Yellow River near Snellville (station 02206500). 100 >- >-- <( UJ ~ UJ w.. I 0 ~ i !!l :::J UJ 0 >-- ,<_( ~ Note: A base f l ow of 5.0 cubic f eet per seco nd a t station 02206500 indi ca t es a like l y base flow of 8.6 c ubi c feet per second a t s t atio n -' <( :;; a. UJ <( I UJ w.. ...J 0 I >-- UJ UJ 0 !!l a: <( a: I <( z 0 UJ Ul 0 10 5 2 "I ' 10 100 D I SC HARG E OF YELLOW RIVER AT GAG I NG STA TI O N NEAR S N ELLV ILL E ( 134 SQU AR E MI L ES) , IN CUB I C F EE T PER SECO ND 200 Figure 12 . - Relation of concurrent base flows for Apalachee River near Bethlehem and Yellow River near Snellville showing method for estimating low-flow index (7-day minimum flow with a 10-year recurrence interval). 5. 7Q10 for station 02206500 is 5 ft3fs, which is used to enter the regression in figure 12 and from it, the low-flow index for Apalachee River is determined to be 8.6 ft3/s, which is 8.6/70 or 0.123 of the mean annual discharge. 6. By entering a 7Q10 of 0.123 of mean annual flow on the abscissa scale of the draft-storage diagrams for Region B (figs. Sa, b, c, d, e), draft rates for various storage values can be read from the ordinate scale for frequencies of 2, 5, 10, 20, and 30 years. A summary of these data for a 10-year frequency follows: Draft rate (1) (2) Ratio to mean Cubic feet per annual flow second (1) X 70 0.15 .18 .2 .3 .4 .5 .6 10.5 12.6 14 21 28 35 42 Storage required (3) (4) Ratio to mean Acre-feet annual runoff (3) X 50,700 0.0009 .0078 .0042 .023 .052 .11 .18 45 142 212 1,170 2,640 5,580 9,130 35 The volume of storage required to maintain a given draft rate may be estimated simply by noting the value of the storage curve intersecting the left ordinate axis, the draft-rate axis, of the diagram at the desired draft rate. A storage estimate by this method is the best that can be obtained for such streams using the regional data available. General Utility of the Data Data and methods of application, as presented in this repnrt, are expected to be useful for development of small and medium streams having less than 1,000 mi2 of drainage area. This report is intended for reconnaissance-type studies to determine the suitability of a given stream site, or the relative merits of several alternative stream sites. The curves herein provide the best available estimate of the volume of storage that will be required on an ungaged stream. Flows of very large streams are, generally, not amenable to regional analysis methods. Also, most of the large rivers in Georgia have already been extensively developed by construction of storage reservoirs. Any additional projects on large streams will likely be complex and costly and will require an intensive engineering study. Increasing demands for water supplies on small and medium size streams and the resulting requirements for low-flow augmentation are the most obvious source of demands for draft-storage analyses. However, this is not the only type of need that such analyses can supply. At present, many operators of municipal and industrial wastewater treatment facilities on streams having insufficient flows during droughts are likely to consider alternatives to the considerable expense of high levels of waste treatment. One alternative is low-flow augmentation provided from a storage reservoir on the stream. A more likely solution is to build an off-channel wastewater storage lagoon in which all or part of the treated wastewater would be stored during periods when streamflow is inadequate to provide the dilution required to meet water-quality standards. In this situation, draft-storage curves could also be helpful. This application is an extension and modification of a method previously proposed by G. G. Goddard (U.S. Geological Survey, written commun., 1970). Consider this example: Water-quality standards are to be maintain~d in a stream below a wastewater outfall during droughts having recurrence intervals up to 10 years. The statistics are: A. Drainage area of receiving stream, 54 mi2. B. Index flow (7Q10) of stream, 8.6 ft3/s. C. Average rate of effluent flow, 3.5 ft3/s. D. Desired dilution factor, 3 parts streamflow to 1 part wastewater flow. E. Streamflow required to maintain dilution, 10.5 ft3/s. 37 data in each of four regions in the State, conforming, in part, to physiographic provinces. These analyses supersede previously available draftstorage analyses which were not on a frequency basis, or were applicable only to limited areas. This report describes previously unpublicized methods for using draftstorage curves in the design process of off-channel storage or landtreatment facilities for effluents from wastewater treatment plants. This significantly extends the usefulness of draft-storage analyses to include wastewater treatment plant design as well as water-supply problems. The report also presents a method for making estimates of storage requirements in problem areas, such as in much of south Georgia, where wastewater receiving streams are frequently in a condition of no flow and, therefore, do not have a low-flow index for use in the conventional method for making storagerequirement estimates. SELECTED REFERENCES Beard, L. R., 1943, Statistical analysis in hydrology: American Society of Civil Engineers Transactions, v. 108, P 1110-1160. Carter, R. F., 1970, Evaluation of the surface-water data program in Geor- gia: U.S. Geological Survey Open-File Report, 65 P Carter, R. F., and Gannon, W. B., 1965, Surface-water resources of the Yellow River basin in Gwinnett County, Georgia: Georgia Geologic Survey Information Circular 22. Carter, R. F., and Putnam, s. A., 1977, Low-flow frequency of Georgia streams: U.S. Geological Survey Water-Resources Investigations 77-127, 101 P Chow, V. T., 1964, Handbook of applied hydrology: New York, HcGraw-Hill Book Company, p. 8-28. Dawdy, D. R., and Matalas, N. C., 1964, Analysis of variance, covariance, and time series, in Chow, V. T., Handbook of applied hydrology: New York, McGraw-HillBook Company, P 8-68 to 8-90. - Hardison, C. H., 1966, Storage to augment low flows, in St. Hilda's College, Oxford, England, 1965, Proceedings Reservoir Yield Symposium [Medmenham, Buckinghamshire, England] Water Research Association Paper 8, 41 p. Inman, E. J., 1971, Flow characteristics of Georgia streams: U.S. Geologi- cal Survey Open-File Report, 262 p. Riggs, H. C., 1966, Hydrologic data for reservoir design, in Hydrology of Lakes and Reservoirs, v. 2: International Science Hydrology Publication 71, Symposium of Garda, p. 540-550. - - -1968, Frequency curves: U.S. Geological Survey Techniques of WaterResources Investigations, Book 4, Chapter A2, 15 p. 39 Table 2.- Flow characteristics at selected sites on Georgia streams (Type- of station: D, daily-discharge gaging station; P, partial-record gaging station. Mean annual discharges: values in parentheses were estimated from plate 1. Low-flow index: minimum 7-day flow having a recurrence interval of 10 years) Mean ann ua l dischar ge, ad justed to period 1941-70 Low-flow index Station number Name Location Type Drainage area (mi2) Cubic feet per second Cubic feet per second per square mile Cubic Ratio feec pe r to secon d mean Region Savannah River Basin 02177000 Chattooga River Lat 3448'50"", long 8318'22"", near Clayton Oconee County, S.C., on l eft bank 150 ft downstream from bridge on U.S. Highway 76, 2.8 mi upstream from Stekoa Creek, 7 mi southeast of Clayton, 9 mi downstream from War Woman Creek , and 9 mi upstream from conflu- ence with Tallulah River. D 207 630 3.04 02178400 Tallulah River Lat 3453'25"", long 8331'50"", near Clayton Rabun County, on right bank 100 ft downstream from county high- way bridge, 120 ft downstream from Persimmon Creek, 8 mi up- stream from Burton Dam, and 10.3 mi west of Clayton. D 56.5 181 3. 20 02180400 Tiger Creek Lat 3447'04", long 8324'58", at Lakemont Rabun County, on county highway bridge, at Lakemont. p a26 (70. 2) (2.70) 02182000 Panthe r Creek Lat 3440'40", long 8320'43", near Toccoa Stephens County , on left bank at Yonah Settlement, 0.2 mi up- stream from mouth, and 7 rni north of Toccoa. D 32.5 67. 7 2.08 02188500 South Beaverdam Lat 34.10'52"", l ong 8256'38"", Creek at Elbert Co unt y , on left bank 50 Dewy Rose ft upstream from highway bridge, l mi northeast of Dewy Rose, and 3 mi upstream from confluence with North Beaverdam Creek. D 35.8 50.5 1.41 02191200 Hudson River at Homer Lat 3420'15", long 8329'17", Banks County, on downstream side of center pier of bridge on State Highway 15 at Homer, 3 .6 mi upstream from Webb Creek, and 10.8 mi upstream from Grove Creek . D 61.1 105 1.72 02191300 Broad River Lat 3404'24"", long 8300'12"', above Carlton ~fa dis on County, at State Highway 72, 2.8 mi northeast of Carlton. p 760 (1,100) (1.45) 02191700 South Fork Broad River near Comer Lat 34 o3 '40 "", long 83 o9 '22 .. , ~~ dison County, at State Highway 72, 2 mi west of Comer. p a89 (120) (1.35) 02191800 Falling Creek Lat 3400'14", long 8248'32", near Elbert County, at county road Fortsonia 1. 8 mi southwest of Fortsonia. p a44 (48.4) (1.10) 02191900 Long Creek Lat 3350'30", long 8303'50", near Lexington Oglethorpe County, at State Highway 10 , 3.5 mi southeast of Lexington. p a31 (34. 1) ( 1.10) 02 192000 Broad River near Bell Lat 3358 '27"", long 8246' 12"", Elbert County, at downst ream side of main channel pier of bridge on State Highway 17, 0.5 mi downstream from Long Creek, 1 mi south of Bells Crossroads, and 12 mi southeast of Elberton. D a1,430 1,740 1. 22 120 0.19 B 54 .30 B 12 .17 B 14 .21 B 5.4 .11 B 28 .27 B 180 .16 B 11 .085 B 1.9 .039 B 3.6 .11 B 200 .11 B a Approximatel y. 41 Table 2.- Flow characteristics at' selected sites on Georgia streams - Continued (Type of station : D. daily-discharge gaging station; P, partial -record gaging station . Mean annual dis.charges: values in parentheses were estimated from plate 1. Low - flow index: minimum ?-day flow having a recurrence interval of 10 years) Mean annual discharge, adjusted t o period 1941 - 70 Low-flow index Station number Name Location Type Drainage area (mi2) Cubic feet per second Cubic feet per second per square mile Cubic Ratio feet per to second mean Region Ogeechee River Basin--Continued 02202000 Ogeechee River at Scarboro Lat 32'42 ' 38" , long 81'52'46", Jenkins County , on left bank 15 ft downstream from abandoned highway bridge at Scarboro , 3. 5 mi downstream from Sculls Creek, 6.5 mi upstream from Horse Creek and 7 . 5 mi southeast of Millen . D a1, 940 1,780 02202500 Ogeec hee River near Eden Lat 32'11 '29", long 81'24 ' 58" , Effingham County , on right bank 600 ft downstream f r om bridge on U. S. Highways 25 , 80, and 280, 2 mi west of Eden, 2 mi upstream from Seaboard Coast Line Railroad bridge, and 3 mi upstream from Black Cr eek . D a2 , 650 2,380 02202800 Canoochee Creek Lat 32'36'19", long 82'15 ' 21" , near Emanuel County , at U. S. Highway Swainsboro 80, 4 . 75 mi east of Swainsboro . p a 55 (49 . 5) 02203000 Canoochee River Lat 32'11 ' 05", l ong 81'53'20" , near Claxton Evans County, on right bank 400 ft upstream from bridge on Stat e Highway 73, 2 mi northeast of Claxton, and 10 mi upstream from Lotts Creek. D a555 467 0. 91 . 89 ( . 90) . 84 180 0.10 c 240 .10 c 0 D 1.6 . 0034 D 02204300 Little Cotton Indian Creek near Stockbridge 0220500 Wildcat Creek near Lawren c eville 02205500 Pew Creek near Lawrenceville 02206000 Shetley Creek near Norcross 02206500 Yellow River near Snellville Al tamaha River Basin Lat 33'31 '26", long 84' 11' 21" , Henry County , at State Highway 42, 2 . 5 mi southeast of Stockbridge . p a 50 Lat 34'00 ' 08" , long 84'00'18", Gwinnett Co un ty, on left bank 75 ft upstream from highway bridge, 0 . 7 mi upstream from mouth, 1.1 mi east of State Highway 20 , and 3.2 mi north of Lawrenceville. D 1. 59 Lat 33'56'05", l ong 84'01' 00" , Gwinnett County , on right bank 20 ft upstream from highway bridge, 1 mi upstream from Red- l and Creek , and 2 . 2 mi southwest of Lawrenceville . D 2. 23 Lat 33'57'20", l ong 84'09'50" , Gwinnett County , on ri ght bank 150 ft upstream from hi ghway bridge, 1 mi upstream from mouth , and 2 . 8 mi northeast of Norcross . D . 98 Lat 33'51'11", long 84'04 ' 45 ", Gwinnett County, on left bank at downstream side of county high- way bridge, 3 . 2 mi west of Snellville , 4 mi downstream from Sweetwater Cr eek , 6 . 5 mi north- east of t own of Stone Mountain, and 7.5 mi upstream from Stone Mountain Creek . D 134 (57.5) ( 1.1 5) 2 .1 1. 32 3. 3 1.48 1. 3 1.34 166 1. 23 5.1 . 089 B . 04 . 019 B . 20 06 1 B . 038 . 029 B 5. 0 . 030 B a Approximately . 43 Table 2.- Flow characteristics at selected sites on Georgia streams - Continued (Type of station: D, daily - discharge gaging station; P, partial-record gaging station. Mean annual discharges: values in parentheses were estimated from plate 1. Low-flow index: minimum 7-day flow having a recurrence interval of 10 years} Mean annual discharge, adjusted to period 1941-70 Low-flow index Station numb e r Name Location Type Drainage area (mi2) Cubic feet per second Cubic feet per second per square mile Cubic Ratio feet per to second mean Region Altamaha River Basin--Continued 02213500 Tobesofkee Lat 3248'32 "", long 8345'30"", Creek Bibb County, on right bank at near Macon downstream end of pier of bridge on U.S. Highway 80, 8 mi west of Hacon , and 14 mi upstream from mouth. D 182 196 1.07 8. 5 0.043 B 02214000 Echeconee Cr eek Lat 3245 '54"", l ong 8350'42"" , near Hacon Crawford-Bibb Counties, at county road , 13 mi southwest of Macon . p 147 (154) (1.05) 3.0 .019 c 02214500 Big Indian Lat 3227'20"", long 8344'21"", Creek at Perry Houston County , at municipal waterworks at Perr y , on left bank 300 ft downstream from bridge on U. S. Highway 41, 1 mi downstream from Bay Creek, and 3.2 mi upstream from Flat Creek. D 108 85.3 .79 21 .25 c 02215100 Big Cr eek near Hawkinsville La t 3214'23"", long 8330 '04"", Pulaski County , at State Highway 27, 3 . 5 mi southwest of Hawkinsville. p a155 ( 163) ( 1.05) 5.5 .034 c 02216000 Little Ocmulgee Lat 3200'28"", long 8245'10"", River at Towns Te lfa ir County, at bridge on State Highway 134 at Towns, and 9 mi upstream from mouth. D 325 365 1.11 2.6 .0071 D 02217000 Allen Creek at Talmo Lat 34 o 11' 34 .. , l ong 83 43 '11"", Jackson County, 400 ft upstream from bridge on St ate Highway 11, 0.5 mi north of Ta lmo, and 5 mi upstream f rom con fluence with Pond Fork. D 17.3 26.9 1. 56 2.4 .089 B 02217200 Middle Oconee Lat 3405'42"" , long 8336'21"", River Jackson County, at State High- near Jefferson way 11, 2. 2 mi southwest of Jefferson. p 12 8 (181) (1.42) 12 .066 B 02217300 Cedar Cr eek Lat 3400 ' 43"", long 8344'19"", near Winder Barrow Count y, at county road, 1. 8 mi west of Winde r. p a9.9 (13. 4) (1.35) .21 .016 B 02217500 Middl e Oconee Lat 3356'48"", long 8325'22"", River Clarke County, on left bank 0.5 nea r Athens mi upstream from U.S. Hi ghway 29, 2 mi west of Athens, and 5 mi upstream from Barber Creek. D 398 505 . 0 1. 27 45 .089 B 02217600 Nor th Oconee Lat 34 o 13 '49"", long 83 34' 07"", River Jacks on County , at count y road , near ~laysville 1. 5 mi south of Haysville . p a70 (105) (1. 50) 16 .15 B 02217700 Sandy Creek Lat 3359 '10 "" , long 8322'38"", at Athens Clarke County, a t State Highway 24, near Athens. p a6 1 (82.4) (1.35) 3.8 .046 B 02218500 Oconee River near Greensbo r o Lat 3334'52"", long 8316'22"", Greene County, on right bank 300 ft downstream from bridge on State Highway 12, 1 mi downstream from Town Creek, 5 mi upstre am from Apalachee River , 5 mi west of Greensbor o , and 12 mi downstream from Barnett Shoals Dam . D a1,090 1,310 1.20 150 .11 B a App roxima t ely . 45 Table 2.- Flow characteristics at selected sites on Georgia streams - Continued (Type of station : D, daily-discharge gaging station; P, partial-record gaging station. Mean annual discharges : values in parentheses were estimated from plate 1. Low-flow inde x: minimum 7-day flow having a recurrence interval of 10 ye1rsJ Mean annua l discharge, adjusted to period 1941-70 Low-flow index Sta ti on number Name Location Type Drainage area (mi2) Cubic fee t per second Cubi c feet per second pe r square mile Cubic Ratio feet per to second mean Region Al tamaha River Basin--Continued 02225100 Cobb Creek Lat 32"02'06" , long 82"22'44", near Lyons Toombs County , at Sta t e Highway 56 , 1. 8 mi northeast of Cedar Crossing, and 13 mi northeast of Lyons. p a69 (62 .1) (0.90) 0 02225300 Ohoopee River Lat 32"23'26 "", long 82"18 ' 46 "", near Oak Park Emanuel Co unty, a t U. S. Highway 1, 2.5 mi north of Oak Park . p a620 (552) ( . 89) 10 02225500 Ohoo pee River Lat 32"04 ' 42 ", l ong 82"10 ' 39 " , near Tattnall County , on downstream Reidsville side of pier near center of span of bridge on State Highway 56, 0 . 5 mi downs tream from Brazells Creek, 1.5 mi downstream f rom Rocky Creek , 3 . 5 mi west of Reidsvil l e , 6 mi downstream f r om Pendleton Cr eek , and 14 mi up- st ream from mouth. D al, ll O 996 . 89 34 02226 100 Penholoway Lat 31"34'00", long 81"50 '1 8", Creek Wayne County, on downstream side near Jesup of bridge on U. S. Highway 341, 4 mi so utheast of Jesup , and about 9. 5 mi upstream from mouth. D a2 10 206 98 0 D . 018 D . 034 D D Satil la River Basin 02226200 Sa tilla Rive r near Doug l as Lat 31"24'45 ", long 82"51'01" , Coffee County , a t U. S. Hi ghway 441, 6. 5 nti south of Douglas . p a235 02226500 Satilla River near Waycross Lat 31"14'17"", l ong 82"19 ' 29 "", \-/a re County, on downst ream side of pier near center of span of bridge on State Highway 38 , 3 mi northeas t of Waycross , and 16 mi upstream from Al abaha River. D a 1, 200 02227000 Hur ri cane Cr eek Lat 31"34'00" , long 82"27'50" , near Alma Bacon County , near cen-t er of span on downstream side of high- way bridge on U. S. Hi ghway l, l. 5 mi no rth of Alma, and ll mi upst ream from Ten Ui le Creek. D alSO 02227100 Litt l e Hurri- Lat 31"29'47"", long 82"3 1 '45"" , cane Creek Bacon County , a t State Highway near Alma 64 , 5 mi southwest of Alma . p a6 1 02227200 Little Hu rri- La t 31"25'25 "" , l ong 82"25'59 "", cane Cr eek Bacon Coun t y , at St ate Highway below Alma 4, 8. 5 mi so uth of Alma. p lll 02227300 Alabaha River near Blackshear Lat 31"19 ' 00"", l ong 82"13'36 "", Pierce County , at State Highway 38, 1 mi northeast of Blackshea r. p 438 02227400 Big Satilla La t 31"39 ' 24"", l ong 82"25 ' 55"", Creek Bacon Co unt y , at Sta t e Highway near Alma 4, 8 . 2 mi north of Al ma . p 11 2 02227430 Lit tle Satilla Lat 31 "40 ' 00 .. , long 82"02 ' 23"" Creek at Odum Wayne Co unt y, at St a te Highway 27 a t Odum , 10 mi northwest of Jesup . p a49 (204) 989.0 139 (51. 8) (93.2) (372) (100) (39 . 2) ( . 87) . 82 .92 (. 85) ( . 84) ( . 85) ( .90 ) (.80) 0 13 0 0 0 1. 7 0 0 D . 013 D D D D .0046 D D D a Approximate l y. 47 Table 2.- Flow characteristics at selected sites on Georgia streams -Continued (Type of station: D, daily-discharge gaging sta tion ; P, partial-record gaging station. Mean annual discharges: values in parentheses were estimated from plate 1. Low-flow index: minimum 7-day flow having a recurrence interval of 10 years) Mean annual discharge , adjusted to period 1941-70 Low-flow index Station number Name Location Type Drainage area (mi2) Cubic feet per second Cubic feet per second per square mile Cubic Ratio feet per to second mean Reg ion Suwannee River Basin--Continued 02316200 Willacoochee Creek near Ocilla Lat 31"30 ' 06", long 83"09'43", Irwin County , at State Hi ghway 90, 8 mi southeast of Ocilla . a90 (80.1) 02317500 Alapaha River at Statenville Lat 30"42' 14"", long 82"02'00"", Echols County, at downstream side of left bank pier of bridge on State Highway 94, 0 . 2 mi west of Statenville. D a1,400 1, 070 02317600 Little River Lat 30"42' 12", long 83"07'21"", near Echols County , at county road, Statenville 5.5 mi west of Statenville. p 199 (179) 02317700 Withlacoochee Lat 31"11'54", long 83" 16'21", River Berrie n County, at State High- nea r Nashville way 76, 1.5 mi southwest of Nashville. p 132 (112) 02317800 Little River near Tifton Lat 31"26'21"", l ong 83"33'39 "", Tift County , a t U.S . Highway 82, 3 mi west of Tifton. p a145 (126) 02317900 Ty Ty Creek at Ty Ty Lat 31"28'22 "", long 83"39'47"", Tift County, at U. S. Highway 82, 1 mi west of Ty Ty. a47 (40.0) 02318000 Li ttle River Lat 31"09'18", long 83"32'38", near Adel Cook County, on right bank 500 ft downstream from bridge on State Highway 37, 0 . 5 mi down- stream from Georgia & Florida Railroad bridge, 5. 5 mi upstream from Bear Creek, 6 mi downstream from Warrior Creek , and 7 mi west of Adel. D 577 496 02318500 Withlacoochee River near Quitman Lat 30"47'36", long 83"27'13", Brooks County, at bridge on U. S. Highway 84, 800 ft downstream from Seaboard Coast Line Railroad bridge , 6 mi east of Quitman. D a1,480 1,140. 02319000 Withlacoochee River near Pinetta, Fl a . Lat 30"35 ' 43", long 83"15'35", in NW quarter sec.7, T.2N., R.11E., tiadison County, on right bank 30 ft downstream from !ughway bridge, O. l mi downstream from small tributary, 0 . 3 mi west of Bellville, 5.6 mi east of Pinetta , and 22 mi upstream from mouth. D a2,120 1,700 (0.89) .76 ( . 90) ( . 85) ( .87) (.85) 86 .77 . 80 0 D 25 0.023 D 2.1 .012 D 0 D 0 D 0 D 1.2 .0024 D 8.0 .0070 D 90 053 D 02327200 Ochlockonee River at l1oultrie 02327500 Ochlockonee River nea r Thomas ville a Approximately. Ochlockonee River Basin Lat 31"10 ' 58", long 83"48'32" , Colquitt County, a t State High- way 37, at Houltrie. p a96 Lat 30"52 ' 32", long 84"02'44", Thomas County , on downstream side of left bank pier of bridge on U. S. Highway 84, 2 mi upstream from Seaboard Coast Line Railroad bridge, 4 mi up- stream from Barnetts Creek, 5 mi northwest of Thomasville, and 6 mi downstream from Little Ochlockonee River. D a 550 49 (85.4) 522 ( . 89) 95 0 D 4.9 .0094 D Table 2.- Flow ch ar acter ist ic s at selected si te s on Georgi a streams - Continued ( T y p e o f st a ti o n : D , dai l y - d i scha r g e gagi n g s ta ti o n ; P, p ar ti a l- r eco r d ga gin g sta t io n . Mea n a nnu a l di sc h a rg es: val u es in pa r entheses we r e esti m a t e d f r o m p la t e 1. L ow -flo w in d e x; mi n imum 7-day fl ow hav in g a r ecu r re nce inte r v al of 10 year s) Mean annual dis c harge , ad juste d to period 194 1- 70 l;ow- f l ow index Station number Name Location Type Dr a i n a g e area (mi2) Cubic feet per second Cubic feet pe r second pe r square mile Cubic Ratio feet per to second mea n Region Apalachicola River Basin--Continued 02333600 Yahoola Creek Lat 3432 ' 41", 10ng 8358 ' 08", at Dah l onega Lumpkin County , at Sta t e High- way 52, at Dahlonega . p 31. 3 (7 1. 9) 02335700 Big Creek Lat 3403'02" , long 84 o 16 ' 10 " , near Fulton County , on l ef t bank at Alpharetta downstream side of co unty high- way bridge , 2 . 6 mi so utheast of Alpha retta , and 9 . 4 mi upstream from mouth . D a72 101 02335900 Rottenwoood Creek near Marietta Lat 3354 ' 41 ", long 8428 ' 43" , Cobb Co un ty , at Terre ll Mill Roa d, nea r Ma rietta . p a 15 (1 9. 5) 02336 100 North For k La t 3350 ' 28" , long 84 18 ' 46", Peachtree DeKalb County , at Cl a irmont Creek Roa d, near Atla nta . p 27 . 8 (3 6.7 ) at Atlanta 02336300 Peachtree Creek Lat 33'49 ' 10 "' long 8424 ' 28" , a t At lanta Fulton County , on downstream side of bridge on Nor t hside Dr ive a t Atlan t a, 0 . 4 mi down- stream from Tanyard Branch , and 4 mi ups t ream f r om mouth . D 86 . 8 120 02336400 Nancy Creek La t 3350 ' 54" , long 8425 ' 58", a t Atlanta Fu lton County, a t Wes t Paces Fer ry Roa d, at Atlanta . p 38 . 2 (4 9. 6) 02336800 Swee t water Lat 3348 ' 17 ", long 8447 '1 0" , Cr eek Paulding Co unty , at county road, nea r Hi ram 5. 5 mi southwes t of Hi ra m. p a 50 (72 . 5) 02337000 Swee t wa t er Lat 3346 ' 22" , l ong 84 36 ' 53" , Creek Dougl as County , on r i ght bank near Auste ll 100 f t upst ream from br idge on Interstate H i gh~