IC 36 GULF TROUGH GEORGIA STATE DIVISION OF CONSERVATION DEPARTMENT OF MINES, MINING AND GEOLOGY A. S. FURCRON, Director THE GEOLOGICAL SURVEY Information Circular 36 HYDRAULICS OF AQUIFERS AT ALAPAHA, COOLIDGE, FITZGERALD, MONTEZUMA, AND THOMASVILLE, GEORGIA by Charles W. Sever Prepared in cooperation with the U.S. Geological Survey, Water Resources Divisio-P '7' ATLANTA 1969 CONTENTS Page Abstract ____________________ ---------------------------------------------------------------------------------------------------------------------------------------- 3 Introduction -------------------------------------------------------------------------------------------------------------------------------------------------------- 3 Purpose of the Investigations ----------------------------------------------------------------------------------------------------------------- 3 Well-nurnbering Systern --------------------------------------------------------------------------------------------------------------------------- 3 Previous Investigations --------------------------------------------------------------------------------------------------------------------------- 3 AcknowIedgments --------------------------------------------------------------- --------------------------------------------------------------------- 3 Chemical Quality of Ground Water --------------------------------------------------------------------------------------------------------------- 3 Aquifers and Hydraulic Properties --------------------------------------------------------------------------------------------------------------- 5 Methods of Investigations ______________________ ---------------------------- ------------------------------------------------------------------- 5 Hydraulic Properties of the Aquifers -------------------------------------------------------------------------------------------------- 5 Effects of Pumping ------------------------------------------------------------------------------------------------------------------------------- 6 Aquifer Performance Test at Alapaha, Berrien County, Ga._____________________________________________________________________ 6 Hydraulic Properties of the Aquifer ---------------------------------------------------------------------------------------------------- 6 Aquifer Performance Test at Coolidge, Thomas County, Ga-------------------------------------~------------------------------- 6 Current-Meter Test -------------------------------------------------------------------------------------------~------------------------------------ 7 Hydraulic Properties of the Aquifer -------------------------------------------------------------------------------------------------- 11 ------------------------------------------~-~~~-~~~-1-1--~- Chemical Quality of Water ------------------------------------------------ ------------------------------------------------------------------ 11 Aquifer Performance Test at Fitzgerald, Ben Hill County, Ga.------------------------------------------------------------- 11 Current-Meter Test ----------------------------------------------------------------------------------------------------------------------------------- 13 Hydraulic Properties of the Aquifer --------------------------------------------------------------------------------------------------- 13 Effects of Pumping ------------------------------------------------------------------------------------------------------------------------------- 13 Aquifer Performance Test at the Well Field of Southern Frozen Foods, Inc., Montezuma, Macon County, Ga.------------------------------------------------------------------------ 13 Hydraulic Properties of the Aquifers ------------------------~------------------------------------------------------------------------- 13 Effects of Pumping ------------------------------------------------------------------------------------------------------------------------------- 14 Chemical Quality of Water --------------------------------------------------------------------------------------------------------------------- 14 Aquifer Performance Test at Thomasville, Thomas County, Ga. ------------------------------------------------------------- 14 I Current-Meter Test --------------------------------------------------------------------------------------------------------------------------------- 15 Effects of Pumping ------------------------------------------------------------------------------------------------------------------------------- 15 Hydraulic Properties of the Aquifer --------------------------------------------------------------------------------------------------- 15 Chemical Quality of Water ------------------------------------------------------------------------------------------------------------------- 16 References ------------------------------------------------------------------------------------------------------------------------------------------------------ 16 ILLUSTRATIONS Page Figure 1. Location of study areas and geographic coordinates of the wellnumbering system for southwestern Georgia --------------------------------------------------------------------- 4 2. Alapaha well locations ----------------------------------------------------------------------------------------------------------------- 6 3. Geophysical logs of well 20K2 at Alapaha ------------------------------------------------------------------------------- 7 4. Coolidge well locations ------------------------------------------------------------------------------------------------------------- 7 5. Geophysical logs of wells at Coolidge -------------------------------------------------------------------------------------- 10 6. Theoretical water-level decline with respect to distance from a pumped well located at Coolidge, after 10 years continuous pumping at 100 gpm, 1,000 gpm, and 5,000 gpm. --------------------------------------------------------------- 11 7. Fitzgerald well locations ------------------------------------------------------------------------------------------------------------- 11 8. Geophysical logs of well 20M2 at Fitzgerald ------------------------------------------------------------------------ 12 9. Theoretical water-level decline with respect to distance from a pumped well at Fitzgerald, after 10 years continuous pumping ------------------------------------------------------------------------------------------------------------------------------------------- 13 10. Theoretical water-level decline with respect to distance from a pumped well at Southern Frozen Foods, Inc., well field after one day and one year of continuous pumping at 100 gpm and 1,000 gpm ------------------------------------------------------------------------------------------------------------------------- 14 11. Graph showing theoretical water-level decline with respect to distance from a pumped well at Southern Frozen Foods, Inc., well field after 10 years continuous pumping at 500 gpm, 1,000 gpm, 2,000 gpm, and 4,000 gpm ---------------------------------------------------------------------------------- 14 12. Thomasville well locations -------------------------------------------------------------- ____ -------------------------------------- 15 13. Response of the water level in well 14E15 to periodic pumping of wells 14E10, 14E12, and 14E14, Thomasville well field___________________________________________________ 15 TABLES Page Table 1. Chemical analyses of water --------------------------------------------------------------------------------------------------------- 5 2. Summary of hydraulic coefficients ------------------------------------------------ ------------------------------------------ 6 3. Record of wells ------------------------------------------------------------------------------------ --------------__ -------------------------- 8-9 4. Location and yield of the water-bearing beds in well 20M2 at Fitzgerald --------------------- 13 HYDRAULICS OF AQUIFIERS AT ALAPAHA, COOLIDGE, FITZGERALD, MONTEZUMA, AND THOMASVILLE, GEORGIA Charles W. Sever ABSTRACT The results of aquifer performance tests made on four well fields tapping limestones of Miocene, Oligocene, or Eocene age show tha~ the hydrauli.c properties vary greatly from one limestone aqUIfer to another in southwestern Georgia. Coefficients of transmissibility in the limestones ranged from 120,000 gpd per ft. (gallons per day per foot) at Fitzgerald, Ga., to perhaps as much as 20,000,000 gpd per ft. at Thomasville, Ga. The coefficient of storage ranged from 0.00002 to 0.003. An aquifer performance test made on sand aquifers of Cretaceous age near ~o:r:t~z_uma, Ga., shows the coefficient of transmissibility to be about 60,000 gpd per ft. and the coefficient of storage to be about 0.002. The geophysical and lithologic logs and the drawdown versus distance graphs made for the well fields described in this report should enable prediction of the amount of interference between wells and also aid in determining the proper construction and spacing of wells. Previous Investigations General information about the hydrogeology and water quality of southwestern Georgia are included in Stephenson and Veatch (1915), Cooke (1943), Wait (1960), and Callahan (1964). Herrick (1961) has published detailed lithologic and paleontologic logs of numerous wells in the area, some of which are located within the well fields described in this report. Results of aquifer performance tests made at other well fields in southwestern Georgia are included in reports by Wait (1963) and Sever (1963, 1965). Acknowledgments The author thanks the superintendents of the water departments of each city described herein for their cooperation and assistance. Thanks also are due Mr. John Flatt with Layne Atlantic Com- pany pany; Mr. Mr. JDohanytConarrEwveitrhetJtowhnithCaErrvDerreiltltinDgr~Cllo~mng- Company, Mr. Rowe with Rowe Brothers Dnllmg Company, and Mr. Frank Creasy with Creasy Drilling Company for their assistance in t~sting the aquifers. The author acknowledges the .mter- est and assistance of the staff of the Georgia De- partment of Mines, Mining and Geology, Dr. A. S. Furcron, Director. CHEMICAL QUALITY OF GROUND WATER INTRODUCTION The mineral content of ground water, though Purpose of the Investigations usually higher than that of surface water, does Ground-water investigations have been ~ade not vary seasonally. Surface waters may fluctuate appreciably in both mineral content and tern- at municipal well field~ in Alapaha, .Coohd~e, perature over a short period of time..The chemi- --------weFliltz-gfieeralldd-,ofa-nSdouTthhoemrna-sFvriollzeena-nFdooadts,th-eInmc~dMuos~tnteal-- - cal compositton_i}:f_g:r'QUI!d_w::lt~_var~~--~~~_re-_~ sultof thetype of rock and the length of time the zuma, Ga. (fig. 1), for the purposes of evaluatu~g water is in the aquifer. Water from a limestone the quantity and quality o~ $Tound water ava:Il- aquifer is usually high in mineral content becau.se able for industrial and mumcipal use and provid- of the solubility of the calcium carbonate, while ing information for the orderly development of this resource. These investiga~ions were ~ade .by water from a relatively insoluble sand and gravel aquifer may be low in dissolved minerals. Gener- the U. S. Geological Survey, m. coopera:t1?n With ally, the farther from the recharge area the water the Georgia Department of Mmes, Mmmg and Geology, as part of a project ~o evaluate the is withdrawn from the aquifer, the higher the mineral content. ground-water resources of Georgia. Most drinking water standards are based on those set by the U. S. Public Health Service in Well-numbering System The field well-numbering system used in this report is based upon geographic coordinates. Each well is assigned two numbers separated by a let- ter. The first number and the letter refer :to th.e coordinate system shown on figure 1 and Iden~I fies the individual 71;2-minute quadrangle m which the well is located. The final number repre- sents the well numbered serially within a quad- rangle. Accordingly, well 18G18 was the 18th well to be located within the 71;2-minute quadrangle represented by coordinates 18 and G. . Wells for which drill cuttings are available 1962 for water used on common carriers engaged in interstate commerce (table 1). At the same time, the American Water Works Association en,. dorsed these standards and recommended that they be adopted as minimum criteria for all pub- lic supplies in the United States. . Hardness classification by the U. S. Geological Survey is related to parts per million (ppm) of calcium carbonate: 0-60 ppm -------------------------------- soft 61-120 ppm _________________________________moderately hard 121-180 ppm ---------------------------------hard have been given a Georgia Geological S?rvey (GGS) number. These numbers are shown m ~a ble 3. Drill cuttings from these w~lls are on file in the sample library of the G~orgm Department of Mines, Mining and Geology m Atlanta. more than 180 ppm _______________________very hard Chemical analyses of water from wells at Coolidge, Montezuma, and Thomasville are given in table 1. 3 T s I _;=--- --u- -j---"T f ' ,J' L Tl"- I/ ,, I', \ R l) / ~! L'. -, ;-+-- ---.n.- __j -..._J - \ D0 0 L Y II p u L A s K I ' \ \ (D0 DGE 1 o STEV.ART )'wEBSTER: suMTER~- I f'<, 1--t-!~.,'_ -----+=---+~-------lf-i-t----+-+---\-_--H----~-;,._/--1 ~:2E ~ ~ ~ p '1---- 1\/ + --~- - ! - - +~ - =-+~ _n__j_ ---+ ~ \-J~. __) r- ''\ - -+ l - - - - 1---J--1-_ 1--- -'------- _1\1--' ~ C R I S P IIW I I ~ c 0 X ', / 32"oo' v )QUIT~ANI TERREL~' !~~-~--!-- ~--~-- N l - ~r __, '- r-' i /--r,_ ~ ~LEE ' I ~-... 1---- - -~ s\ E~ H 1 L L '---- I\ ~a0: M l' R 1f"' N D 0 L p H ' \. r n ' I ' \' '" I r u II T R N E R I' ' L~FlITZGERALD L___ _] -----= ~ ~ L lil ._____, ---r- - 7 \ C L A y ~ ~ 1 ~-. r+--- 1 P C L H 0 U N ) D 0 U G H E R T Y W 0 R T H I R W I N ~ ( 2 h ~I K ( L _J I u-\_ \ _n_') "7 - p - T , --~ -'"'-t---- - -- I l,J ! .--l T I F T 1>--- -~~ I A APAHA 1 31"30' r ' \_ ~~r-J--hI~~'E-=+A-~R~-L~~v-rt-I--s+-A-K~~E--R+-__~.,-.l'vb--~--+-~---t--b------fr.-l_r-------1+-r--.-~-IJ'-,~-~~~~-"-' ~-'-\-~ ~ lJ __ l BE R R I E N \ ~~H--~1\,--~---FI\,~~~=c~~~.~---_(~M~I-T+C-H_E_L+L---~--C-O~L--Q~U--1-T~T-,,~~~1--+---~-~L 1~z-~-G-i-~~'-rI T--_rL--Mt--4I---L-}-L_f__E_-_,-R-~_~_j~_~~-_--/-"-r----+----f--~---~-IhI ----+- -e----- -~f-.~-~~T~t)-~r-,-C-~- Oj('~-,-O-1 L'-f-K-~)_~'j_1--(-, t- ~f1rL.-) _N-_I_E__-___R)1 A L A. ' ' ~ ~ II I \ 31 oo' COOUDGE . 'r L. -, F E ' SEMINOLE 1 \ ~ I D ECA T U R \ _; GRA D ~ ') T H 0 M A S11 I ~ I B R0 \THOMASVILLE _~ O W N D E S '1 r0 K s l'l \..f--\ jJ 1 0 '\J__ -+--- t-- G-~~~AI--I'-I-- F L 0 ~-I D A I \ - - -r-- - -+-- _ 1.,_ c 5 6 7 8 9 I 0 I I 12 13 14 15 16 17 18 19 20 21 L___ _L_______L----,-___t______L_ ____::;E.:_:AS:_:T:_-_W~E:_:S:_:T___:W;:_:E:.:L::L:...-:.J~W:_:IM.:;B::.:E::.RllN:_:_G::___:C:_::r,::CP~R~D.:.:.NI.:.::AcT_:E:...:.:S..:JY~:_T:_:E::_:M_:_l____~:--_j__ __L____L___ _j 30 30 85"oo' 94"3o' s4"oo 93"30 83"oo' EXPLANATION * Location of city where well field was tested. 10 0 10 20 30MILES Figure 1. Location of study areas and geog1aphic coordinates of the well-nwmbering syste1n for southwestern Georgia. 4 Table 1. Chemical analyses of water (Analyses by U. S. Geological Survey unless otherwise shown) z 0 .......sc 0 .... " ~ ~ 0itt=8 c .:0: .8 c"; u Parts per million ~ u 0 5 ";' ?:. 8 8 .3 ~ ..3, ~ ~ 0 0 C/J. ll. .~, -~ :u2 Hardness as caco, ~G . ."c 0 .. 10 " "'., .... ., c ~ U0 ,."c ~ ;> -~0tn~:="~ 5" f8 ~".-"s C/J.~ U. S. Public Health Service drinking-water standards 0.3 250 250 a1.2 45 500 COOLIDGE 15G7 10-6-64 74 25 0.09 65 31 22 3.5 148 185 15 0.7 0.1 420 288 166 615 8.0 5 SOUTHERN FROZEN FOODS, INC., MONTEZUMA 20M2 8-2-61 75 23 0.06 22 9.0 3.5 0.8 114 0.8 THOMASVILLE 3.0 1.2 0.0 122 92 0 192 7.9 0 14E10 14E10 14E11 t14E12 14E12 14E12 c14E12 2-5-38 12-2-51 12-2-51 1949 3-8-58 12-2-51 8-1-61 71 24 0.02 45 22 7.9 1.0 153 77 71 25 .10 ---- ------ ---- 157 71 25 ---- 157 ---- 18 .1 ---- 31.8 69.6 76 22 .00 47 20 7.8 1.0 158 82 71 26 .07 47 22 6.9 ---- 157 79 72 22 .04 48 21 7.8 1.0 158 78 7.8 0.3 0.1 265 203 7.5 203 418 7.8 ---- 7.5 210 425 7.7 ---- 11.6 308 187 7.9 ---- 9.0 .4 .0 288 200 70 418 7.8 2 7.6 .4 .1 271 208 416 1 8.0 .7 .0 298 206 77 ------ 7.5 25 ' ~ Recommended mrunmum concentratwn for area covered by thrs report (average mrunmum daily air temperature of G3.g _ o o Law and Company, analyst. 70.6 F). c-Sampled-after-30-days..of-Pur>:LPintg._~~~~~~~~ AQUIFERS AND HYDRAULIC PROPERTIES Most municipalities and industries located in the Georgia Coastal Plain obtain their water supply from wells that tap water-bearing sedimentary rocks called aquifers. Most of these aquifers are actually aquifer systems, as they are not a single water-bearing bed but generally include several interconnected or related water-bearing beds. Wells that tap limestone aquifers in southwestern Georgia obtain most of their water from a few thin, highly-permeable beds rather than from the entire thickness of the aquifers. Knowledge of the stratigraphic position, thickness, distribution, and yield of these beds, as well as the hydraulic properites of the aquifer system, aid in the proper construction and spacing of wells. In Georgia, the Suwannee Limestone, the Ocala Limestone, and the Lisbon Formation make up the principal artesian aquifer system, the most extensively used aquifer system in south Georgia. Methods of Investigations The geologic age of the different rock formations was determined by examining samples of the rocks penetrated by the drilling of water wells. The tops and bottoms of each formation were lo- cat~d and t:aced from well to well by comparing their electr:Ical and gamma-radiation properties. Water-bearmg zones within the aquifer system were located by means of a current meter. A cali- per log was made to determine the inside diameter of t_he well bore. Th~ hydraulic properties of an aqmfer were determmed by pumping a well at a known constant rate and measuring the water- level c~ange in the pumped well or in nearby ob- servatiOn wells penetrating the aquifer. 'These data _are u~ed to solve equations which express the relatiOnship between the hydraulic properties of an aquifer and the lowering of water levels near a pumped well (Theis, 1935 and Ferris and others 1962). ' Hydraulic Properties of the Aquifers The principal hydraulic properties influencing the development of an artesian aquifer are the coefficien~s. of transmissib~lity (T) and storage (S). The a?Ihty of an aqmfer to transmit ground water IS expressed by the coefficient of transmissibility, which is defined as the rate of flow of water in gallons per day, through a vertical strip of the aquifer 1 foot wide and extending the fv.ll 5 saturated thickness under a hydraulic gradient of 100 percent (1 foot per foot). The storage properties of an aquifer are expressed by the coefficient of storage, which is defined as the volume of water released from storage per unit surface area of the aquifer per unit decline in head or water level. Hydraulic properties of the aquifers tested during these studies are summarized in table 2. Table 2. Summary of hydraulic coefficients. Well field Alapaha Coolidge Fitzgerald Montezuma (Southern Frozen Foods) Thomasville Aquifer Suwanee Limestone do. Principal artesian aquifer Providence Sand, Cusseta Sand and Blufftown Formation Ocala Limestone Coefficient of transmissibility (gpd/ft) 240,000 1,300,000 120,000 60,000 20,000,000 Coefficient of storage gals Not determined 0.00002 .003 .002 Not determined Effects of Pumping When a well is pumped, water levels decline in a funnel shape, called a cone of depression, with the greatest drawdown at the pumped well. With continuous pumping, water is taken from storage at greater distances from the pumped well and the cone of depression grows in size and depth until a state of equilibrium is reached. Waterlevel decline is theoTetically directly proportional to the pumping rate and diminishes outward from the pumped well. In a multiple well system, a cone of depression is formed around each pumped well. When the cones overlap, the wells are said to interfere and water levels decline in a manner directly proportional to the pumping rates and inversely proportional to the logarithm of the distance between wells. Pumping from wells in artesian aquifers has a widespread effect on water levels. Hydraulic properties detemined for the various well fields described in this report were used to evaluate the magnitude of interference between theoretical wells located within or near the well fields for different pumping rates. In determining the theoretical drawdown near a pumping well the aquifers tapped were assumed to be insulated from other aquifers by thick impermeable aquicludes. However, water will permeate through most materials if sufficient time and pressure are involved. Most artesian aquifers receive recharge through permeable breaks in the confining aquicludes or by rleakage from the aquiclude itself. Therefore, the predicted drawdowns given for well fields in this report probably are conservative. AQUIFER PERFORMANCE TEST AT ALAPAHA, BERRIEN CO., GA. The city of Alapaha has two municipal wells (20K2 and 20K4). Locations of the two wells are shown on figure 2 and their construction data are summarized in table 3. During construction of well 20K2, the driller collected samples of the rock penetrated by the well and permitted the author to make electricresistivity and self-potential logs of the upper part of the well before the casing was installed. 400 100 FEET I I 20K2 Well and number Figu?e 2. Alapaha well locations. After completion, these two types of logs were made of the lower part of the well and a gammaradiation log was made of the entire well. Figure 3 shows these logs and a summary description of the rock samples. The well taps the Suwannee Limestone which is the uppermost member of the principal artesian aquifer system in Berrien County. Hydraulic Properties of the Aquifer On August 25, 1965, a short aquifer performance test was made by measuring the recovery of the water level in well 20K2 for a half hour after it had been pumped at 41 gpm (gallons per minute) for about 24 hours. The coefficient of transmissibility of the Suwannee Limestone at Alapaha is estimated to be about 240,000 gpd per ft. AQUIFER PERFORMANCE TEST AT COOLIDGE, THOMAS COUNTY, GA. Prior to 1902, Coolidge obtained its municipal water supply from two large, shallow dug wells. 6 SELFPOTENTIAL 0 CURVE MV --1 25 I- ELECTRICALRESIST! VI TY CURVE GEOLOGY GAMMA-RADIATION CURVE SERIES FORMATION LITHOLOGY Undifferentiated Quartz sand -----~ w Lt(.) 100 0::: ::J Cf) 0 z <[ _j 200 3 0 _j w (lJ Iww 300 LL z ... I 368 Ia.-. w 400 0 Seale change OHMS of 1+---loo--..j casing Hawthorn Clayey sand Formation w I Clay z w 0 0 ~ ji:iI~ Sandy clay Phosphatic sand ~ / /4..0' IoS~~-~( ~~),CZcJ::: (5 i5G7 0 I 188 100 200 300 FEET I I I Figure 4. Coolidge well locations. period of about two months, the city was almost out of water. The city then decided to drill another well. In February, 1964, Rowe Brothers Drilling Co., Tallahassee, Fla., drilled a new well (15Gll) about 65 feet east of well 15G7 (fig. 4). Construction data of these wells are summarized in table 3. During construction of well 15Gll, electric-resistivity and self-potential logs were made of the upper part of the well before installing the casing; then after completion, these two types of logs were made of the lower part of the well and a gamma-radiation log was made of the entire well. Electric-resistivity, self-potential, gammaradiation, and caliper logs also were made of well15G6. Samples of the rocks penetrated by well 15G11 were collected by the driller and examined by the author. A summary description of these samples is given on figure 5 together with the logs made of wells 15G6 and 15G11. Current-Meter Test On February 5, 1965, water was allowed to flow into well 15Gll through a fire hose at a rate of about 400 gpm while a current meter traversed the well. All the water put into the well apparent- 7 Table 3. Record of wells Use of water: ES, emergency supply; IS, industrial supply; N, none; OW, observation of water level; PS, public supply Geophysical logs: C, caliper; OM, current meter; ER, electrical-resistivity; SP,* self-potential; GR, gamma-radiation Well numbers Field City GGS Owner Driller Altitude of land Well Date surface depth drilled (ft) (ft) Casing Size From To (in.) (ft) (ft) Screen Settings Size From To (in.) (ft) (ft ALAPAHA 20K2 20K4 2 1368 City of Alapaha Dayton Everetts 1965 291 550 8 0 368 none ------ ---- 1 ------ do. W. R. McGrew 1948 or 49 291 545 8 0 350 ( ?) none ------ ---- COOLIDGE 15G6 ------ 15G7 2 15Gll 3 15G15 1 -----------925 ---- J. 0. Pilkinton City of Coolidge do. do. W. R. McGrew C. C. Renolds Rowe Bros. Unknown 1942 244.6 335 6 1932 252.5 383 6 1963 254.5 385 6 1902 245 ? 4 0 212 0 210 0 234 0 ? none none none none ------ ---- ------ ---- ------ ---- ------ ---- FITZGERALD 19M1 D or4 355 20M1 B or 2 ------- 20M2 A or 1 -----20M3 Cor 3 154 City of Fitzgerald do. do. do. Layne-Atlantic W. R. McGrew Unknown Layne-Atlantic 1953 1925 1898 1948 ? 612 12 0 283 357.8 474 10 0 220 8 198 260 354.6 727 10 0 268 359.3 750 12 0 260 none none none none ------ ---- ------ ---- ------ ---- ------ ---- MONTEZUMA 13S1 1 -------- Southern Frozen Layne-Atlantic Foods Inc. 13S32 2 -------- do. do. -------- ------ 584 10 0 160 8 160 190 8 210 230 8 235 450 8 465 475 -------- ------ 556 10 0 170 8 170 180 8 190 200 8 210 226 8 231 430 8 440 492 8 497 500 8 510 520 -------8 8 8 --------------- 8 8 8 8 8 8 -----190 21 230 23 450 46 ------ ------ 180 19 1 200 21 1 226 23 430 441 492 491 500 511 i THOMASVILLE 14E10 4 14Ell 3 14E12 5 14E13 6 14E14 2 14E15 1 14E16 ------ 56 City of Thomas- Virginia Supply ville & Well 186 do. ? -------- 401 --------------- 132 do. Layne-Atlantic do. Merrill Gray do. ? do. ? do. Layne-Atlantic 1936 262 305 1933 257 550 1949 1950 1917 Prior to 1917 1948 259 399 259 400 257 505 258 548 258 1,635 16 0 112 none 16 0 100 ( ?) none 16 0 95 none 20 0 157 none 12 0 100 none 6 0 ------ none ------ ----- ------ none ------ ----- ------ ---- ------ ----- ------ ----- ------ ----- ------ ----- ------ ----- 8 Depth to water (ft.) Specific capacity of well (gpm/ft) Use of water 216 40 PS PS 17.9 N 180.4 PS 182.6 PS ? N 160 64 PS 150 PS 157 PS 161 43 PS 14.5 IS Geophysical Logs Water-bearing formations ALAPAHA ER, SP, GR Suwannee Limestone do. Remarks COOLIDGE ER,SP,GR,C ER, SP, GR, CM Suwannee Limestone do. do. ? Well abandoned. Well destroyed. FITZGERALD ER, SP, GR, C, CM Suwannee and Ocala Limestone do. do. Suwannee and Ocala Limestone, Lisbon Formation. See Herrick, 1961, p. 20; driller lost circulation at 295 ft. See Stephenson and Veatch, 1915, p. 141. See Herrick, 1961, p. 17. MONTEZUMA Providence Sand do. Blufftown Formation ------~~---- ---~~- Providence Sand do. do. Cusseta Sand Blufftown Formation do. 194 1,000 PS 192 1,060 PS 190 PS PS ES 195 ow N THOMASVILLE CR, CM Suwannee Limestone Suwannee and Ocala Limestone do. do. do. do. Several See Herrick, 1961, p. 400. Well abandoned and cemented back to an unknown depth. See Herrick, 1961, p. 398. 9 WELL 15G6 WELL 15GII WELL- SELF- ELECTRICAL- GAMMA- G E Q LOGy SELF- ELECTRICAL- GAMMA- DIAMETER POTENTIAL RESISTIVITY RADIATION , PoTENTIAL RESISTIVITY RADIATION o CURVE 1 CURVE CURVE CURVE SERIES1FORMATION LITHOLOGY CURVE Hawthorn Quartz CURVE CURVE o I w Formation sand u Sandy i1 cia 0::: ~ (f) 100 0 z <{ I I w 2 Chipola Quartz w Formation sand -----;100 __J 3: 0 ....... 0 w_J 200 en 212 1w-w lL z u 0 I t- Sandstone ~ I Tampa Sandy Limestone limestone :{300 1 s- =-- 13oo I- ()_ w 0 ___WATER-B~ARING ZONE w z ~ !Suwannee r?ssiliferou o Limestone l1mestone 400~~::~~~~--~--------~L___ __ __ __ ~ijt9 __ _______ l ______ j_~~j_ ______ ~_j ________ j 4 6 8 10 12 DIAMETER, IN INCHES 400 Figure 5. Geophysical logs of wells at Coolidge. ly flowed into a thin permeable bed between 326 and 328 feet below land surface. Based upon this test, the water-bearing zone in well 15Gll is the upper few feet of the Suwannee Limestone. However, the driller reportedly lost circulation into another permeable bed at 382 feet, but the lowermost 9 feet of this well were presumably plugged with drill cuttings and the author was unable to test the well from 376 to 385 feet. Hydraulic Properties of the Aquifer On February 11 and 12, 1964, an aquifer performance test was made to determine the hydraulic properties of the Suwannee Limestone 0 Q=IOO gpm I I a=Joo gpm - 2 3 4 1w-~ 5 ~ 6 :;:: 0 ~ 7 <[ a: 0 8 v ~ 9 10 v ~/ -:P Q =Pumping rate - ~ v --- - 12 10 _.,/" I I I III 100 T =1,300,000 5=0.00002 - t = 10 years I I I I I II 1000 DISTANCE, IN FEET FROM PUMPED WELL Figure 6. Theoretical water-level decline with respect to distance from a pumped well located at Coolidge, after 10 years continuous pumping at 100 gpm, 1,000 gpm, and 5,000 gpm. . aquifer at Coolidge, Ga. During the test, well 15G7 was pumped at a rate of 165 gpm and the decline in water level was recorded in wells 15G6, 576 feet to the north, and 15Gll, 65 feet to the east. (See fig. 4.) By analyzing the data obtained during this test, using the nonequilibrium formula (Ferris and others, 1962), the coefficient of transmissibility was determined to be about 1,300,000 gpd per ft. The coefficient of storage was determined to be about 0.00002. Effects of Pumping The amount of interference in nearby wells by a pumped well, all tapping the Suwannee Limestone at Coolidge, can be estimated using the graph in figure 6. This graph shows the decline of water levels in wells 10 feet to 1,000 feet from a well pumped continuously for 10 years at rates of 100 gpm, 1,000 gpm, or 5,000 gpm. For example, figure 6 shows that pumping a well continuously for 10 years at 5,000 gpm would cause a decline of about 10 feet in a well 100 feet away and about 8 feet in a well 1,000 feet away. With intermittent pumping, the decline should be less than that shown on figure 6. Chemical Quality of Water Water pumped from the municipal wells in Coolidge does not exceed the recommended maximum concentration for chemical constituents and is suitable for municipal, irrigation and many industrial uses although it is very hard (288 ppm). Much of its hardness is noncarbonate and is due to dissolved sulfate. A chemical analysis of water from well 15G7 is given in table 1. AQUIFER PERFORMANCE TEST AT ~~~FITZGERALD;-BEN -HI:&I:rCOUNTY-,GA. The city of Fitzgerald obtains its water supply from four deep drilled wells, three of which (20M1, 20M2, and 20M3) are located at the water works on Hooker Street (fig. 7). The fourth well (19M1) is located at the corner of Bragg and Ocmulgee Streets. Construction data for these four wells are given in table 3. Samples of the ACL RR DO 1000 0 1000 FEET Figure 7. Fitzgerald well locations. 11 EXPLANATION 20Ml Well and number CURRENT- WELL- SELF ELECTRICAL- METER DIAM POTENTIAL RESISTIVITY 0 TRAVERSE CURVE CURVE CURVE GAMMARADIATION CURVE GEOLOGY ~ERIES FORMATION LITHOLOGY 100 w 200 (.) Lt 0:: ::> (j) 266 Bottom a z <[ 300 _j ~ - 0 _j w CD 1ww- 400 r-- lL z I" 1- Cwl... 500 1a of cos ina {_ ~--~--~ - j+O -50+H 1 M~ < i ) > > ~ } i :; Scale Jhonge MV 1+-50->i Hawthorn w z w (.) 0 - Formation 4o~<:' ~~() ~_d- ~ ,~ 700 ,.... s ,- - I I I Claiborne Group Sandy limestone 0 I00 200 0 5 I0 REVOLUTIONS DIAMETER, PER MINUTE IN INCHES FiguTe 8. Geophysical logs of well 20M2 at FitzgeTald. 12 rocks penetrated by wells 19M1 (GGS 355) and 20M3 (GGS 154) were collected by the driller and later examined and described by S. M. Herrick (1961, p. 17-20). During April, 1965, the pump in well 20M2 was pulled out for repairs. While the pump was out of the well, the author made electric-resistivity, selfpotential, gamma-radiation, caliper, and currentmeter logs of the well. These logs together with a brief summary of Herrick's descriptions of the rock samples are given on figure 8. Current-Meter Test On April 6, 1965, water was allowed to flow through two fire hoses at a rate of about 700 gpm into well 20M2 while a current meter traversed the well. Table 4 summarizes the data obtained by this test. Four permeable beds were located between 300 and 720 feet. The most permeable bed was at the contact between the Suwannee and Ocala Limestones at a depth of 339 to 340 feet. This bed is estimated to yield about 45 percent of the water pumped by the municipal wells at Fitzgerald and to be capable of yielding up to 3,000 gpm to a well. Hydraulic Properties of the Aquifer From April 1 to April 16, 1965, a water-level recorder was maintained on well 20M2 to record the drawdown and recovery of the water level in response to the intermittent pumping of wells 20M1 and 20M3 located nearby. Pumping of well 20M1 (98 feet away) at a rate of 500 gpm for 8 hours caused a decline in the water level in well 20M1 of about 5 feet. Pumping of well 20M3 (204 feet away) at a rate of 1,000 gpm for 8 hours -~caused a decline_of_about5_feet in well 20Ml. Analysis of the data obtained onAprTfi2, 1965, " by using Theis' (1935) nonequilibrium formula shows that the coefficient of transmissibility of the aquifers tapped by these wells is about 120,000 gpd per foot and that the coefficient of storage is about 0.003. Effects of Pumping The amount of interference by a pumped well with nearby wells that tap the same limestones as the municipal wells at Fitzgerald can be estimated for long periods of time using the graph in figure 9. This graph shows the decline in water level at distances of 10 feet to 1,000 feet from a well pumped continuously for 10 years at 500 gpm, 1,000 gpm, or 5,000 gpm. For example, figure 9 0 I I I I I 1_1 I I I I II Q= 500 gprn 10 Q=\000 gpm 20 30 f- w ~ 40 z z 50 ;;:: 0 0 ~ 60 a: 0 70 80 v90 100 10 / / o'~ a~<:o>o~ v 7 Q =Pumping rate T =120,000 gpd/ft s =o.oo3 1 t =I 0 years I I I III I Ll I Ill 100 1000 DISTANCE, IN FEET FROM PUMPED WELL Figure 9. Theoretical water-level decline with respect to distance from a pumped well at Fitzgerald, after 10 years continuous pumping. shows that a well pumped continuously for 10 years at 1,000 gpm will cause declines about 15 feet in a well located 100 feet away and about 10 feet in a well located 1,000 feet away. AQUIFER PERFORMANCE TEST AT THE WELL FIELD OF SOUTHERN FROZEN FOODS, INC., MONTEZUMA, MACON COUNTY, GA. Sou-th-ern-F-rozellFoodS-~ -IllC.~---ObtEdiiSpartm-ffS~-----~ water from two wells, 13S31 and 13S32, located on their property in Montezuma, Ga. and part from the city of Montezuma. The industry reportedly drilled another well during 1965. Wells 13S31 and 13S32 were drilled by LayneAtlantic Co. in April, 1960, and July, 1962, respectively. Construction data for these wells are summarized in table 3. Hydraulic Prop,erties of the Aquifers On April 27 and 28, 1965, an aquifer performance test was made at the Southern Frozen Foods, Inc., well field to determine the hydraulic properties of the sand aquifers tapped by their wells. During the test, well 13S31 was pumped at 525 Table 4. Location and yield of the water-bearing beds in well 20M2 at Fitzgerald. Amount of Dep,th to top of Thickness Estimated total well .yield Estimated maximum yield casing permeable bed Altitude of of bed sup,plied by each bed of each bedl (feet) (feet) top of bed (feet) (percent) (gpm) 300 55 2 20 266 339 16 1 45 632 -277 4 15 718 -363 2 20 1,500 3,000 1,000 1,500 lMaximum yield is based upon a maximum pumping level of 300 feet below land surface. 13 0 o=IIOO lgp~;~l~ iday- . - I - '-1-1- 2 Q= 100 gpm; 1= 1veer 4 / / 6 /, 8 L 10 9;--1:/>.... / 12 ~, 0,~ fw~ 14 z ~oo3 - 16 z ~ 18 0 / ~ 20 a:: 0 22 / // / ~;;'pe / ~ 24 r;;}a/o 26 v 28 30 / 32 / / / Q=Pumping role T =60,000 5=0.002 t =Pumping lime I 34 10 I I I I II 100 I J I LI I 1000 DISTANCE, IN FEET FROM PUMPED WELL Figure 10. Theoretical wate?-level decline with respect to distance from a pumped well at Southern Frozen Foods, Inc., well field after one day and one year of continuous pumping at 100 gpm and 1,000 gpm. gpm for an undetermined length of time ; then the pump was stopped at 4:10 p.m. on April 27 and the water-level recovery in well 13S32, located 550 feet to the northeast, was recorded for the next 22 hours. By analyzing the recovery curve using the modified nonequilibrium formula, the coefficient of transmissibility of the combined Providence Sand, Cusseta Sand, and Blufftown Formation aquifers was determined to be about 60,000 gpd per foot. Their coefficient of storage was determined to be about 0.002. Effects of Pumping The amount of interference by a pumped well with nearby wells in the Southern Frozen Foods, Inc., well field can be estimated using the graph in figure 10. This graph shows the decline in water level at distances of 10 feet to 1,000 feet from a well pumped continuously for one day and one year at pumping rates of both 100 gpm and 1,000 gpm. For example, pumping a well at 1,000 gpm for one day will cause a decline of 7 feet in the water level of a well 500 feet away. With continued pumping, the decline increases and after one year the water level in a well 500 feet away will have declined about 18 feet. With intermittent pumping, the decline should be less than that shown on figure 10. The amount of interference by wells in the Southern Frozen Foods, Inc., well field with municipal or other wells located in the area can be 6 I I I I I II - .. I I . .. I III Q=500 gpm 10 Q=IOJO~ -- 20 ~ ~1--- 30 :...---~ ------ --- 40 -'2.00~ ~ --------- fw- w 50 ______..,'-""' LL. z 60 2 ~ 70 0 ;;:: ~ 80 / ~0eJo; P v / / 0 Q =Pumping role 90 / 100 v T =60,000 s =0.002 t = 10 years v / 110 120 130 100 II I J l I I II 1000 10,000 DISTANCE, IN FEET FROM PUMPED WELL Figure 11. Graph showing theoretical water-level decline with respect to distance from a pumped well at Southern Frozen Foods, Inc., well field after 10 years continuous pumping at 500 gpm, 1,000 gpm, 2,000 gpm, and 4,000 gpm. estimated using the graph in figure 11. This graph shows the water-level decline in wells 100 to 10,000 feet from a well continuously pumped at 500 gpm, 1,000 gpm, 2,000 gpm, and 4,000 gpm, for a period of 10 years. For example, figure 11 shows that continuous pumping for 10 years at a rate of 1,000 gpm in a well at Southern Frozen Foods, Inc., would cause a water-level decline of about 14 feet in a well 5,000 feet away. However, with intermittent or seasonal pumping the decline should be less than that shown on figure 11. Chemical Quality of Water Water pumped from the industrial wells at Southern Frozen Foods, Inc., is moderately hard (92 ppm) and of good chemical quality. It does not exceed the recommended maximum concentration for chemical constituents and would be suitable for municipal, irrigation, and many industrial uses. However, its fluoride (1.2 ppm) content is at the recommended maximum concentration for consumption. A chemical analysis of water from well 20M2 is given in table 1. AQUIFER PERFORMANCE TEST AT THOMASVILLE, THOMAS COUNTY, GA. The city of Thomasville obtains its water from 5 wells spaced 70 to 700 feet apart (fig. 12) that tap the Ocala Limestone. A continuous record of changes in water level caused by pumping of these 5 wells is being obtained from a sixth well (14E15) located within the well field. Construction data for all of the wells at the Thomasville well field are given in table 3. 14 Sampies of the rocks penetrated. by weils 14E16 (GGS 56), 14E11 (GGS 186), 14E13 (GGS 401), and 14E16 (GGS 132) were collected by the driller and later examined and described by Herrick (1961, p. 398-401) and Applin and Applin (1964, p. 212-216). A geologic summary of well 14E16 (GGS 132), a 1,635 foot deep exploratory well, follows: .14EI3 Figure 12. Tho'Y!~asville well locations. Current-Meter Test On February 4, 1964, water was injected through two fire hoses at a rate of about 760 gpm into well 14E15 while a current meter traversed the well. All of the water appeared to flow into a 7-foot-thick permeable bed in the Ocala Limestone at a depth of 420 to 427 feet below land surface. No additional permeable beds were found in the well. Effects of Pumping During Decemb,er, 1963, a water-level recorder was installed on well 14E15 and a record was kept of the time each pump in the municipal well field was started or stopped. Figure 13, a copy of the recorder graph of well 14E15 for December 26 to 30, 1963, shows how the water level changed in response to pumping from three of the Thomasville wells. The water level generally oscillated up and down with diminishing amplitude for about 2 minutes after a pump was started 14E12 0 z ..J !w";;' ll: 195.2 ' - - 2 6_ __,__ _2_7- - ' - - 2 - 8_ ___,___ _2_9--'----3-0----' DECEMBER, 1963 Figure 13. Response of the water level in well 14E15 to periodic pumping of wells 14E10, 14E12, and 14E14, Thomasville well field. or stopped. The amount and direction of this oscillation and also the change in the watel level depended upon whether the pump was started or stopped, the pumping rate, and the distance from the observation well to the pumped well. Well 14E12 is located about 310 feet west of the observation well and was pumped at a rate of 1,170 gpm. Well 14E10 is located about 310 feet to the southwest and was pumped at a rate of 1,000 gpm. Well 14E14 is located about 95 feet to the southwest and was pumped at a rate of 500 gpm. Hydraulic Prop,erties of the Aquifer Tli:e-lack~of~aevelopment_of_a-drawdown~cone--- around the Thomasville well field after prolonged pumpage indicates that the aquifer tapped by the Thomasville wells is extremely permeable. This permeability probably results in part from ground-water solution of the limestone along numerous joints created during folding and faulting of the rocks in the Thomasville area (Sever, 1966). Aquifer performance tests were made at the Thomasville well field by recording the drawdown of water levels in well 14E15 caused by pumping other municipal wells at rates o 500 gpm to 3,200 Geologic Age Pliocene to Recent (undifferentiated) Miocene (undifferentiated) Oligocene (undifferentiated) upper Eocene (Ocala Limestone) middle Eocene (Lisbon Formation) middle Eocene (Tallahatta Formation) Geologic summary of well 14El6 Lithology Thickness (feet) Clayey sand 35 Sand and sandy 135 limestone Fossiliferous 130 limestone Dolomitic limestone 725 Glauconitic limestone 587 Glauconitic sand 23 Depth (feet) 35 170 300 1,025 1,612 1,635 15 gpm. Close spacing of wells, oscillation of water levels after each pump was started or stopped, intermittent pumping of nearby wells, and the short time interval between pumping cycles of municipal wells make the data obtained from the aquifer performance tests difficult to interpret. However, analyses of these data suggest that the coefficient o;f transmissibility of the principal artesian aquifer system at Thomasville is ex- tremely large-possibly as large as 20 million gpd per foot. The coefficient of storage is small- probably less than 0.00001. Chetnical Quality of Water Water from the municipal wells in Thomasville is very hard (187-210 ppm) but contains mineral concentrations that are well below the recommended limits for drinking water. The concentrations of dissolved minerals from three of the municipal wells are summarized in table 1. Thomasville has recently built a modern watersoftening plant but chemical analyses of the treated water are not presently available. However, the treated water should be much softer and lower in dissolved solids. REFERENCES Applin, E. R. and Applin, P. L., 1964, Logs of selected wells in the Coastal Plains of Georgia: Georgia Geol. Survey Bull. 74, 229 p. Callahan, J. T., 1964, The yield of sedimentary aquifers of the. Coastal Plain, Southeast River Basins: U. S. Geol. Survey Water-Supply Paper 1669-W, 56 p. Cooke, C. W., 1943, Geology of the Coastal Plain of Georgia: U. S. Geol. Survey Bull. 941, 121 p. Cooper, H. H., Jr., and Jacob, C. E., 1946, A generalized graphical method of evaluating constants and summarizing well field history: Am. Geophys. Union Trans., v. 27, no. 4, p. 526-534. Ferris, J. G., Knowles, D. B., Brown, R. H., and Stallman, R. W., 1962, Theory of aquifer tests: U. S. Geol. Survey Water-Supply Paper 1536-E, 174 p. Herrick, S. M., 1961, Well logs of the Coastal Plain of Georgia: Georgia Geol. Survey Bull. 70, 462 p. Lang, S. M., 1961, Methods for determining the proper spacing of wells in artesian aquifers: U. S. Geol. Survey Water-Supply Paper 1545-B, 16 p. Sever, C. W., 1963, Ground-water resources of Bainbridge Air Base, Decatur County, Georgia: Georgia Geol. Survey Min. Newsletter, v. 16, nos. 1 and 2, p. 39-43. ---1965, Ground-water resources of Bainbridge, Ga.: Georgia Geol. Survey Inf. Circ. 32, 10 p. ---1966, Miocene structural movements in Thomas County, Ga.: U. S. Geol. Survey Prof. Paper 550-C, p. C12-C16. Stephenson, L. W., and Veatch, J. 0., 1915, Underground waters of the Coastal Plain of Georgia: U. S. Geol. Survey Water-Supply Paper 341, 539 p. Theis, C. V., 1935, The relation between the lowering of the piezometric surface and the rate and duration of discharge of a well using ground-water storage: Am. Geophys. Union Trans., v. 16, p. 519-524. ----1963, Spacing of wells in shortcuts and special problems in aquifer tests: U. S. Geol. Survey WaterSupply Paper 1545-C, p. 113-115. U. S. Public Health Service, 1962, Drinking water standards: U. S. Public Health Service Pub. 962. Wait, R. L., 1960, Source and quality of ground water in southwestern Georgia: Georgia Geol. Survey Inf. Circ. 18. ----1963, Geology and ground-water resources of Dougherty County, Ga.: U. S. Geol. Survey WaterSupply Paper 1539-P, 102 p. 16