STREAM-TEMPERATURE CHARACTERISTICS IN GEORGIA

U.S. GEOLOGICAL SURVEY

Prepared in cooperation with the GEORGIA DEPARTMENT OF NATURAL RESOURCES ENVIRONMENTAL PROTECTION DIVISION

Water-Resources Investigations Report 96-4203 STREAM-TEMPERATURE CHARACTERISTICS IN GEORGIA

By T.R. Dyar and S.J. Alhadeff ______

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 96-4203

Prepared in cooperation with

GEORGIA DEPARTMENT OF NATURAL RESOURCES ENVIRONMENTAL PROTECTION DIVISION

Atlanta, Georgia 1997 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary

U.S. GEOLOGICAL SURVEY Charles G. Groat, Director

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

District Chief U.S. Geological Survey U.S. Geological Survey Branch of Information Services 3039 Amwiler Road, Suite 130 Denver Federal Center Peachtree Business Center Box 25286 Atlanta, GA 30360-2824 Denver, CO 80225-0286 CONTENTS Page Abstract ...... 1 Introduction ...... 1 Purpose and scope ...... 2 Previous investigations...... 2 Station-identification system ...... 3 Stream-temperature data ...... 3 Long-term stream-temperature characteristics...... 6 Natural stream-temperature characteristics ...... 7 Regression analysis ...... 7 Harmonic mean coefficient ...... 7 Amplitude coefficient...... 10 Phase coefficient ...... 13 Statewide harmonic equation ...... 13 Examples of estimating natural stream-temperature characteristics ...... 15 Panther Creek ...... 15 West Armuchee Creek ...... 15 Alcovy River ...... 18 Altamaha River ...... 18 Summary of stream-temperature characteristics by river basin ...... 19 Savannah River basin ...... 19 Ogeechee River basin...... 25 Altamaha River basin...... 25 Satilla-St Marys River basins...... 26 Suwannee-Ochlockonee River basins ...... 27 Chattahoochee River basin...... 27 Flint River basin...... 28 Coosa River basin...... 29 Tennessee River basin ...... 31 Selected references...... 31 Tabular data ...... 33 Graphs showing harmonic stream-temperature curves of observed data and statewide harmonic equation for selected stations, figures 14-211 ...... 51

iii ILLUSTRATIONS Page Figure 1. Map showing locations of 198 periodic and 22 daily stream-temperature stations, major river basins, and physiographic provinces in Georgia...... 4 2. Map showing names of major streams and locations of 78 stream-temperature stations used to compute harmonic stream-temperature regression equations ...... 5 3. Graph showing generalized harmonic stream-temperature curve showing harmonic equation coefficients ...... 6 Figures 4-8. Maps showing: 4. Harmonic mean stream temperatures for 78 natural-condition stations ...... 8 5. Residuals of harmonic mean stream temperatures for 78 natural-condition stations ...... 9 6. Amplitude coefficients for 78 natural-condition stations ...... 11 7. Residuals of amplitude coefficients for 78 natural-condition stations ...... 12 8. Phase coefficients for 78 natural-condition stations ...... 14 Figures 9-11. Graphs showing harmonic stream-temperature curves of observed data and statewide harmonic equation for stations: 9. Panther Creek near Toccoa, Georgia (station 02182000), September 1959 to June 1974 . . . 16 10. West Armuchee Creek near Subligna, Georgia (station 02388000), May 1960 to April 1982 ...... 16 11. Alcovy River above Covington, Georgia (station 02208450), October 1972 to July 1975 ...... 17 Figure 12. Map showing locations of principal power-generating facilities and major reservoirs in Georgia ...... 20 13. Map showing locations of cities in Georgia having populations greater than 10,000 ...... 24 Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide harmonic equation for stations: 14. Chattooga River near Clayton, Georgia (station 02177000), September 1957 to December 1984 ...... 52 15. Tallulah River near Clayton, Georgia (station 02178400), July 1964 to August 1984 . . . . . 52 16. Panther Creek near Toccoa, Georgia (station 02182000), September 1959 to June 1974 ...... 53 17. Savannah River near Iva, South Carolina (station 02187500), May 1958 to November 1984 ...... 53 18. Beaverdam Creek at Dewy Rose, Georgia (station 02188500), February 1958 to July 1975 ...... 54 19. Savannah River near Calhoun Falls, South Carolina (station 02189000), September 1957 to July 1974 ...... 54 20. North Fork Broad River above Toccoa, Georgia (station 02189050), October 1958 to August 1968 ...... 55 21. Denmans Creek near Toccoa, Georgia (station 02189100), October 1958 to October 1969 ...... 55 22. North Fork Broad River near Toccoa, Georgia (station 02189500), October 1958 to August 1968 ...... 56 23. Bear Creek near Mize, Georgia (station 02189600), October 1958 to July 1968 ...... 56 24. North Fork Broad River near Lavonia, Georgia (station 02190000), July 1958 to August 1968 ...... 57 25. Toms Creek near Eastanollee, Georgia (station 02190100), July 1962 to August 1968...... 57 26. Toms Creek tributary near Avalon, Georgia (station 02190200), July 1962 to August 1968...... 58

iv ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide harmonic equation for stations:—Continued Figure 27. Toms Creek near Martin, Georgia (station 02190500), October 1962 to September 1968...... 58 28. North Fork Broad River near Carnesville, Georgia (station 02191000), October 1962 to September 1970...... 59 29. Hudson River at Homer, Georgia (station 02191200), August 1962 to July 1975...... 59 30. Broad River near Bell, Georgia (station 02192000), October 1956 to October 1979 ...... 60 31. Little River near Washington, Georgia (station 02193500), October 1954 to June 1974...... 60 32. Butler Creek at Fort Gordon, Georgia (station 02196820), March 1968 to July 1976 ...... 61 33. Savannah River at Augusta, Georgia (station 02197000), February 1958 to July 1973 ...... 61 34. Savannah River at Burtons Ferry near Millhaven, Georgia (station 02197500), August 1957 to June 1979 ...... 62 35. Brier Creek near Thomson, Georgia (station 02197520), November 1958 to July 1976 ...... 62 36. Brushy Creek near Wrens, Georgia (station 02197600), May 1958 to July 1976 ...... 63 37. Brier Creek near Waynesboro, Georgia (station 02197830), October 1954 to September 1983...... 63 38. Brier Creek at Millhaven, Georgia (station 02198000), July 1954 to June 1979 ...... 64 39. Savannah River near Clyo, Georgia (station 02198500), May 1938 to December 1984 ...... 64 40. Ogeechee River at Scarboro, Georgia (station 02202000), October 1954 to June 1979...... 65 41. Ogeechee River at Oliver, Georgia (station 02202190), August 1974 to December 1984 ...... 65 42. Ogeechee River near Eden, Georgia (station 02202500), May 1937 to October 1984 . . . . . 66 43. Canoochee River near Claxton, Georgia (station 02203000), September 1954 to December 1984 ...... 66 44. Canoochee River at Fort Stewart, Georgia (station 02203519), February 1958 to December 1984 ...... 67 45. Peacock Creek at McIntosh, Georgia (station 02203559), September 1966 to November 1977 ...... 67 46. South River at Bouldercrest Road at Atlanta, Georgia (station 02203800), August 1970 to December 1984 ...... 68 47. South River at State Highway 155 near Atlanta, Georgia (station 02203965), October 1970 to December 1984...... 68 48. Pates Creek at Buster Lewis Road near Flippen, Georgia (station 02204285), February 1978 to August 1983 ...... 69 49. South River near McDonough, Georgia (station 02204500), December 1957 to September 1982...... 69 50. South River at State Highway 81 at Snapping Shoals, Georgia (station 02204520), August 1970 to December 1984 ...... 70 51. Wildcat Creek near Lawrenceville, Georgia (station 02205000), October 1956 to September 1976...... 70 52. Yellow River near Snellville, Georgia (station 02206500), August 1956 to November 1984 ...... 71

v ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide harmonic equation for stations:—Continued 53. Yellow River (Conyers Intake) at Conyers, Georgia (station 02207300), July 1974 to December 1984 ...... 71 54. Yellow River near Covington, Georgia (station 02207500), December 1957 to September 1982...... 72 55. Yellow River at Porterdale, Georgia (station 02207540), July 1974 to June 1979 ...... 72 56. Yellow River at State Highway 212 near Stewart, Georgia (station 02208005), July 1974 to December 1984...... 73 57. Alcovy River above Stewart, Georgia (station 02209260), May 1972 to December 1984 ...... 73 58. Ocmulgee River near Jackson, Georgia (station 02210500), December 1957 to December 1984 ...... 74 59. Towaliga River near Jackson, Georgia (station 02211300), June 1960 to December 1973 ...... 74 60. Falling Creek near Juliette, Georgia (station 02212600), July 1964 to January 1985 ...... 75 61. Ocmulgee River (Macon Intake) at Macon, Georgia (station 02212950), June 1974 to December 1984 ...... 75 62. Ocmulgee River at Macon, Georgia (station 02213000), May 1937 to December 1975 ...... 76 63. Walnut Creek near Gray, Georgia (station 02213050), August 1962 to July 1976 ...... 76 64. Tobesofkee Creek above Macon, Georgia (station 02213470), May 1967 to December 1973 ...... 77 65. Tobesofkee Creek near Macon, Georgia (station 02213500), October 1955 to October 1966...... 77 66. Tobesofkee Creek near Macon, Georgia (station 02213500), November 1966 to September 1974...... 78 67. Ocmulgee River near Warner Robins, Georgia (station 02213700), November 1970 to December 1984 ...... 78 68. Ocmulgee River near Bonaire, Georgia (station 02214265), August 1974 to December 1984 ...... 79 69. Big Indian Creek at Perry, Georgia (station 02214500), April 1954 to January 1974 ...... 79 70. Ocmulgee River at Abbeville, Georgia (station 02215260), February 1958 to June 1979...... 80 71. Ocmulgee River at Lumber City, Georgia (station 02215500), June 1954 to December 1984 ...... 80 72. Allen Creek at Talmo, Georgia (station 02217000), October 1956 to June 1974 ...... 81 73. Middle Oconee River near Athens, Georgia (station 02217500), August 1956 to October 1977...... 81 74. North Oconee River (Athens Intake) at Athens, Georgia (station 02217740), July 1974 to December 1984...... 82 75. Oconee River at Barnett Shoals near Watkinsville, Georgia (station 02218000), July 1974 to December 1984...... 82 76. Oconee River near Greensboro, Georgia (station 02218500), July 1956 to December 1984 ...... 83 77. Apalachee River near Buckhead, Georgia (station 02219500), July 1956 to July 1976 ...... 83

vi ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide regression equation for stations: 78. Whitten Creek near Sparta, Georgia (station 02220550), December 1960 to August 1976...... 84 79. Murder Creek near Monticello, Georgia (station 02221000), August 1956 to December 1973 ...... 84 80. Oconee River at Milledgeville, Georgia (station 02223000), May 1937 to December 1984 ...... 85 81. Oconee River near Hardwick, Georgia (station 02223040), July 1974 to December 1984 ...... 85 82. Oconee River at State Highway 57 near Toomsboro, Georgia (station 02223250), February 1979 to December 1984 ...... 86 83. Big Sandy Creek near Jeffersonville, Georgia (station 02223300), August 1958 to December 1973 ...... 86 84. Oconee River at Dublin, Georgia (station 02223500), November 1954 to November 1976 ...... 87 85. Oconee River at Interstate Highway 16 near Dublin, Georgia (station 02223600), October 1973 to December 1984...... 87 86. Rocky Creek near Dudley, Georgia (station 02224000), August 1954 to March 1984 ...... 88 87. Altamaha River near Baxley, Georgia (station 02225000), December 1957 to December 1984 ...... 88 88. Pendelton Creek at State Highway 86 below Ohoopee, Georgia (station 02225470), July 1979 to December 1984...... 89 89. Ohoopee River near Reidsville, Georgia (station 02225500), July 1954 to October 1982 ...... 89 90. Altamaha River near Jesup, Georgia (station 02225990), August 1974 to December 1984 ...... 90 91. Altamaha River at Doctortown, Georgia (station 02226000), May 1937 to October 1979 ...... 90 92. Altamaha River near Gardi, Georgia (station 02226010), November 1974 to December 1984 ...... 91 93. Penholoway Creek near Jesup, Georgia (station 02226100), December 1958 to July 1984 ...... 91 94. Altamaha River at Everett City, Georgia (station 02226160), December 1970 to December 1984 ...... 92 95. Satilla River at Waltertown, Georgia (station 02226475), August 1974 to December 1984 ...... 92 96. Satilla River near Waycross, Georgia (station 02226500), May 1937 to August 1974 . . . . . 93 97. Satilla River at State Highways 15 and 121 near Hoboken, Georgia (station 02226582), August 1974 to December 1984 ...... 93 98. Hurricane Creek near Alma, Georgia (station 02227000), January 1955 to June 1982. . . . . 94 99. Little Satilla River near Offerman, Georgia (station 02227500), January 1955 to September 1983...... 94 100. Satilla River at Atkinson, Georgia (station 02228000), May 1954 to October 1984 ...... 95 101. Suwannee River at Fargo, Georgia (station 02314500), August 1957 to November 1984 ...... 95 102. Alapaha River near Alapaha, Georgia (station 02316000), March 1953 to July 1984...... 96

vii ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide regression equation for stations—Continued 103. Alapaha River at Statenville, Georgia (station 02317500), January 1954 to August 1974...... 96 104. New River at U.S. Highway 82 near Tifton, Georgia (station 02317718), July 1979 to December 1984 ...... 97 105. Withlacoochee River near Valdosta, Georgia (station 02317749), November 1974 to December 1984 ...... 97 106. Withlacoochee River at State Highway 94 near Valdosta, Georgia (station 02317757), November 1974 to December 1984 ...... 98 107. Little River at U.S. Highway 82 near Tifton, Georgia (station 02317800), August 1977 to June 1982 ...... 98 108. Little River near Adel, Georgia (station 02318000), October 1955 to March 1961...... 99 109. Little River near Adel, Georgia (station 02318000), April 1961 to July 1974...... 99 110. Withlacoochee River near Quitman, Georgia (station 02318500), August 1957 to December 1984 ...... 100 111. Okapilco Creek at U.S. Highway 84 at Quitman, Georgia (station 02318725), November 1974 to December 1984...... 100 112. Withlacoochee River near Clyattville, Georgia (station 02318960), November 1974 to December 1984 ...... 101 113. Ochlockonee River near Moultrie, Georgia (station 02327205), July 1979 to December 1984 ...... 101 114. Ochlockonee River near Thomasville, Georgia (station 02327500), April 1954 to December 1984 ...... 102 115. Tired Creek near Cairo, Georgia (station 02328000), May 1954 to July 1974 ...... 102 116. Ochlockonee River near Calvary, Georgia (station 02328200), August 1974 to December 1984 ...... 103 117. Chattahoochee River near Leaf, Georgia (station 02331000), September 1957 to August 1976...... 103 118. Chattahoochee River near Cornelia, Georgia (station 02331600), February 1968 to November 1984 ...... 104 119. Chestatee River at State Highway 52 near Dahlonega, Georgia (station 02333500), October 1956 to September 1976 ...... 104 120. Chattahoochee River near Buford, Georgia (station 02334500), May 1957 to August 1977...... 105 121. Chattahoochee River near Norcross, Georgia (station 02335000), October 1957 to September 1976...... 105 122. Big Creek near Alpharetta, Georgia (station 02335700), May 1960 to September 1976...... 106 123. Chattahoochee River at Atlanta, Georgia (station 02336000), May 1937 to December 1938 ...... 106 124. Chattahoochee River at Atlanta, Georgia (station 02336000), November 1957 to September 1979...... 107 125. Peachtree Creek at Atlanta, Georgia (station 02336300), July 1959 to December 1984 ...... 107 126. Chattahoochee River at Interstate Highway 285 near Atlanta, Georgia (station 02336502), July 1975 to December 1984...... 108

viii ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide regression equation for stations:—Continued 127. Sweetwater Creek near Austell, Georgia (station 02337000), May 1957 to December 1984 ...... 108 128. North Fork Camp Creek at Atlanta, Georgia (station 02337100), October 1963 to July 1970 ...... 109 129. Chattahoochee River near Fairburn, Georgia (station 02337170), July 1965 to December 1984 ...... 109 130. Dog River at State Highway 166 near Fairplay, Georgia (station 02337438), July 1974 to May 1979...... 110 131. Snake Creek near Whitesburg, Georgia (station 02337500), October 1959 to July 1984 ...... 110 132. Chattahoochee River near Whitesburg, Georgia (station 02338000), February 1958 to December 1984 ...... 111 133. Chattahoochee River at U.S. Highway 27 at Franklin, Georgia (station 02338500), February 1958 to December 1984 ...... 111 134. Chattahoochee River (LaGrange Intake) near LaGrange, Georgia (station 02338720), July 1974 to December 1984 ...... 112 135. Yellowjacket Creek near LaGrange, Georgia (station 02339000), August 1956 to September 1970 ...... 112 136. Chattahoochee River at West Point, Georgia (station 02339500), September 1957 to September 1974 ...... 113 137. Chattahoochee River at West Point, Georgia (station 02339500), October 1974 to December 1984 ...... 113 138. Long Cane Creek near West Point, Georgia (station 02339720), July 1974 to December 1984 ...... 114 139. Mountain Oak Creek near Hamilton, Georgia (station 02340500), August 1956 to June 1974 ...... 114 140. Chattahoochee River at Columbus, Georgia (station 02341500), October 1940 to September 1974 ...... 115 141. Upatoi Creek near Columbus, Georgia (station 02341800), April 1965 to September 1983 ...... 115 142. Pataula Creek near Lumpkin, Georgia (station 02343200), August 1962 to November 1973 ...... 116 143. Chattahoochee River at Columbia, Alabama (station 02343500), November 1940 to April 1958 ...... 116 144. Chattahoochee River at Alaga, Alabama (station 02344000), January 1964 to July 1974 ...... 117 145. Chattahoochee River near Steam Mill, Georgia (station 02344040), October 1974 to December 1984 ...... 117 146. Flint River at State Highway 138 near Jonesboro, Georgia (station 02344180), May 1958 to December 1984...... 118 147. Flint River at State Highway 54 near Fayetteville, Georgia (station 02344190), July 1975 to December 1984 ...... 118 148. Camp Creek near Fayetteville, Georgia (station 02344300), July 1960 to September 1970 ...... 119 149. Flint River at Ackert Road near Inman, Georgia (station 02344380), July 1975 to December 1984 ...... 119

ix ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide regression equation for stations:—Continued 150. Flint River at State Highway 92 above Griffin, Georgia (station 02344400), July 1975 to December 1984...... 120 151. Flint River near Griffin, Georgia (station 02344500), August 1956 to July 1976 ...... 120 152. Line Creek near Senoia, Georgia (station 02344700), September 1964 to July 1976 . . . . . 121 153. Potato Creek near Thomaston, Georgia (station 02346500), July 1956 to June 1974 . . . . . 121 154. Flint River near Culloden, Georgia (station 02347500), April 1954 to June 1979 ...... 122 155. Whitewater Creek below Rambulette Creek near Butler, Georgia (station 02349000), April 1954 to November 1973 ...... 122 156. Flint River at Montezuma, Georgia (station 02349500), May 1954 to December 1984 ...... 123 157. Turkey Creek at Byromville, Georgia (station 02349900), July 1954 to June 1982...... 123 158. Flint River at State Highway 27 near Vienna, Georgia (station 02350001), July 1979 to December 1984...... 124 159. Kinchafoonee Creek at Preston, Georgia (station 02350600), May 1954 to July 1984 . . . . 124 160. Flint River at Albany, Georgia (station 02352500), May 1954 to December 1984 ...... 125 161. Flint River (Putney Intake) near Putney, Georgia (station 02352790), August 1974 to December 1984 ...... 125 162. Flint River at Newton, Georgia (station 02353000), August 1956 to October 1984 ...... 126 163. Pachitla Creek near Edison, Georgia (station 02353400), October 1954 to November 1973 ...... 126 164. Ichawaynochaway Creek at Milford, Georgia (station 02353500), April 1954 to July 1984 ...... 127 165. Flint River at Bainbridge, Georgia (station 02356000), April 1954 to July 1973 ...... 127 166. Flint River below State Docks at Bainbridge, Georgia (station 02356015), July 1974 to December 1984...... 128 167. Spring Creek near Iron City, Georgia (station 02357000), August 1957 to July 1978 . . . . 128 168. Cartecay River near Ellijay, Georgia (station 02379500), June 1957 to August 1975. . . . . 129 169. Ellijay River at Ellijay, Georgia (station 02380000), June 1957 to July 1974 ...... 129 170. Coosawattee River near Ellijay, Georgia (station 02380500), May 1963 to August 1983...... 130 171. Scarecorn Creek at Hinton, Georgia (station 02382000), May 1959 to July 1974 ...... 130 172. Coosawattee River at Carters, Georgia (station 02382500), July 1965 to December 1972 ...... 131 173. Rock Creek near Fairmount, Georgia (station 02383000), July 1957 to September 1972...... 131 174. Coosawattee River near Pine Chapel, Georgia (station 02383500), June 1957 to December 1972 ...... 132 175. Coosawattee River near Calhoun, Georgia (station 02383540), August 1974 to December 1984 ...... 132 176. Conasauga River (Dalton Intake) near Dalton, Georgia (station 02384748), July 1974 to December 1984 ...... 133 177. Holly Creek near Chatsworth, Georgia (station 02385800), July 1960 to June 1983...... 133 178. Conasauga River at Tilton, Georgia (station 02387000), June 1957 to December 1984 ...... 134

x ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide regression equation for stations:—Continued 179. Conasauga River near Resaca, Georgia (station 02387050), August 1974 to December 1984 ...... 134 180. Oostanaula River at Resaca, Georgia (station 02387500), September 1957 to December 1972 ...... 135 181. Oostanaula River at Interstate Highway 75 at Resaca, Georgia (station 02387502), August 1974 to December 1984 ...... 135 182. West Armuchee Creek near Subligna, Georgia (station 02388000), May 1960 to April 1982 ...... 136 183. Oostanaula River at Rome, Georgia (station 02388500), September 1957 to December 1973 ...... 136 184. Oostanaula River (Rome Intake) at Rome, Georgia (station 02388520), August 1974 to December 1984 ...... 137 185. Etowah River near Dawsonville, Georgia (station 02389000), September 1956 to August 1984...... 137 186. Shoal Creek near Dawsonville, Georgia (station 02389300), June 1958 to June 1974...... 138 187. Etowah River at Canton, Georgia (station 02392000), June 1957 to October 1984 ...... 138 188. Little River near Roswell, Georgia (station 02392500), August 1959 to September 1964...... 139 189. Little River near Roswell, Georgia (station 02392500), October 1964 to June 1975 . . . . . 139 190. Etowah River at Allatoona Dam above Cartersville, Georgia (station 02394000), October 1938 to September 1939 ...... 140 191. Etowah River at Allatoona Dam above Cartersville, Georgia (station 02394000), January 1958 to November 1984...... 140 192. Hills Creek near Taylorsville, Georgia (station 02394950), June 1959 to July 1974...... 141 193. Etowah River above Kingston, Georgia (station 02394980), August 1974 to December 1984 ...... 141 194. Etowah River near Kingston, Georgia (station 02395000), October 1969 to September 1984...... 142 195. Etowah River at Rome, Georgia (station 02396000), September 1957 to December 1984 ...... 142 196. Coosa River near Rome, Georgia (station 02397000), July 1957 to December 1984 ...... 143 197. Cedar Creek near Cedartown, Georgia (station 02397500), June 1957 to December 1984 ...... 143 198. Coosa River near Coosa, Georgia (station 02397530), August 1974 to December 1984 ...... 144 199. Chattooga River at Summerville, Georgia (station 02398000), July 1957 to December 1984 ...... 144 200. Chattooga River at Chattoogaville, Georgia (station 02398037), August 1974 to December 1984 ...... 145 201. Little River near Buchanan, Georgia (station 02411800), May 1959 to August 1975...... 145 202. Tallapoosa River below Tallapoosa, Georgia (station 02411930), July 1974 to November 1984 ...... 146

xi ILLUSTRATIONS—Continued Page Figures 14-211. Graphs showing harmonic stream-temperature curves of observed data and statewide regression equation for stations:—Continued 203. Little Tallapoosa River below Bowdon, Georgia (station 02413210), July 1974 to December 1984 ...... 146 204. Hiwassee River at Presley, Georgia (station 03545000), August 1951 to June 1982...... 147 205. Nottely River near Blairsville, Georgia (station 03550500), August 1951 to June 1982...... 147 206. Nottely River at Nottely Dam near Ivylog, Georgia (station 03553500), September 1951 to July 1974 ...... 148 207. Toccoa River near Dial, Georgia (station 03558000), January 1951 to June 1984 ...... 148 208. Toccoa River near Blue Ridge, Georgia (station 03559000), January 1951 to July 1974 ...... 149 209. Fightingtown Creek at McCaysville, Georgia (station 03560000), January 1951 to June 1974...... 149 210. South Chickamauga Creek at Graysville, Georgia (station 03566800), August 1974 to November 1984 ...... 150 211. West Chickamauga Creek near Lakeview, Georgia (station 03567340), August 1974 to December 1984 ...... 150

xii TABLES Page Table 1. Periodic stream-temperature stations, periods of analyses, selected station information, and harmonic properties ...... 34 2. Stream-temperature daily record stations, periods of analyses, selected station information, and harmonic properties ...... 44 3. Periodic stream-temperature stations used for regression analyses, periods of analyses, selected station information, and harmonic properties ...... 47 4. Estimates of harmonic coefficients for Altamaha River near Gardi using interpolation and observed data compared with estimates from the statewide harmonic equation...... 18 5. Power generating plants in Georgia ...... 21

VERTICAL DATUM

Sea Level: In this report, “sea level” refers to the National Geodetic Vertical Datum of 1929 (NGVD of 1929)—a geodetic datum derived from a general adjustment of the first-order level nets of both the United States and Canada, formerly called “Seal Level Datum of 1929.”

xiii

STREAM-TEMPERATURE CHARACTERISTICS IN GEORGIA

By T.R. Dyar and S.J. Alhadeff

ABSTRACT Stream-temperature data are important inputs for Stream-temperature measurements for 198 stream water-quality models. In 1974, the Georgia periodic and 22 daily record stations were analyzed Department of Natural Resources, Environmental using a harmonic curve-fitting procedure. Statistics of Protection Division (EPD), with assistance from the data from 78 selected stations were used to compute a U.S. Geological Survey (USGS), designed and statewide stream-temperature harmonic equation, constructed a seasonal stream assimilative capacity derived using latitude, drainage area, and altitude for (SAC) model as an aid to stream assessments in natural streams having drainage areas greater than about Georgia. The SAC model has been used to provide 40 square miles. Based on the 1955–84 reference statistics for the design and operation of waste-treatment period, the equation may be used to compute long-term facilities to help ensure compliance with various natural harmonic stream-temperature coefficients to water-quality standards and to quantify stream within an on average of about 0.4 ° C. assimilative capacity. Basin-by-basin summaries of observed long-term Stream-temperature data along with curves stream-temperature characteristics are included for determined by least-squares simple harmonic fitting of selected stations and river reaches, particularly along the data were presented for 146 stream-temperature Georgia's mainstem streams. Changes in the stream- stations in Georgia by Dyar and Stokes (1973). The temperature regimen caused by the effects of stream-temperature information for these 146 stations is development, principally impoundments and thermal suitable for input to the SAC model or other such water- power plants, are shown by comparing harmonic curves quality models. However, stream-temperature and coefficients from the estimated natural values to the characteristics have not been estimated for many observed modified-condition values. streams in Georgia for which no data or insufficient data exist. Thus, a simple, reliable method is needed to INTRODUCTION estimate stream-temperature characteristics for sites Stream-temperature characteristics are used to where little or no data exist. assess, manage, and protect the water resources of This study was conducted by the USGS, in Georgia. As body temperature is an indicator of human cooperation with the EPD. The stream-temperature health, water temperature is an indicator of the ability of data used in this study were collected in cooperation a stream to sustain aquatic life and assimilate wastes. with EPD and other Federal, State, and local agencies.

1 Purpose and Scope Previous Investigations This report summarizes the water-temperature Numerous previous stream-temperature studies characteristics of selected stream stations in Georgia, were referred to during the compilation and analysis of and provides a harmonic equation suitable for the information contained in this report. Statewide estimating natural seasonal water-temperature inventories of continuous or periodic records of stream characteristics of most Georgia streams. The harmonic temperatures collected primarily by the USGS were equation described in this report is based on estimates presented for California in a series of reports by of natural seasonal stream-temperature characteristics Blodgett (1970–72) and for North Carolina by Woodard for non-tidal streams in Georgia having drainage basins (1970). More descriptive, graphic summaries on greater than 40 square miles (mi2). Stream-temperature regional-basin, statewide, or national scales have taken characteristics computed by the harmonic equation several forms. Maps depicting gross areal variability of presented in this report may be compared to observed selected stream-temperature characteristics have been stream-temperature data to evaluate how seasonal prepared for Florida (Anderson, 1971), for Washington stream-temperature characteristics of a particular stream (Collings and Higgins, 1973), and for the Nation as a may be deviating from estimated natural characteristics. whole (Blakely, 1966; Steele and others; 1974, Hawkinson and others, 1977). Plots of annual stream- This report builds upon the Statewide summary temperature variations have been reported for numerous report of stream-temperature data presented by Dyar and stations in Montana (Aagaard, 1969), for selected sites Stokes (1973). Seasonal stream-temperature in Georgia (Lamar, 1944), for the upper Delaware River characteristics are computed and analyzed from data basin in New York (Williams, 1971), and for the collected by USGS at 198 periodic and 22 continuous Delaware River at Trenton, N.J. (McCarthy and record stream-temperature stations through 1984, Keighton, 1964). including most of the 146 stations reported by Dyar and Stokes (1973). Annual seasonal temperature variations were distinguished from shorter-term daily variations in The harmonic equations for computing natural stream temperature in reports by Calandro (1969) and seasonal stream-temperature characteristics presented Williams (1971). Studies correlating air and water in this report are based on analyses of 78 stream- temperatures on an annual or seasonal basis include temperature stations having records from about studies by Kothandaraman and Evans (1972), Anderson 1955–84. Analyses of records collected subsequent and Faust (1973), Williams (1971), and Steele (1974). to 1984 could cause changes in these equations. However, based on comparisons of the analyses in Based on seasonal cyclical patterns of stream- this report and Dyar and Stokes (1973), changes likely temperature records commonly observed at numerous will occur slowly. measuring stations, a least-squares, harmonic-analysis regression fit of annual variability was proposed by Throughout this report, the term “natural” is Ward (1963). An evaluation of incremental benefits intended to describe stream temperatures that are obtained by imposing higher-order harmonics in the relatively unaffected by human activities, including analysis (Thomann, 1967; Kothandaraman, 1971) such practices as waste-water return, reservoir concluded that a single-harmonic analytical depiction operation, diversions, or proximity to urban areas. of seasonal variations in stream temperatures explains The term “natural” is subjective and rigorous evaluative 85–95 percent of the observed variability in annual procedures are not applied to prove the validity of its records. A modification of the basic single-harmonic use. Similarly, the term “modified” connotes that approach was reported by Tasker and Burns (1974) observed stream temperatures likely are affected by for specific application to regions where streams are human activities. The terms “stream temperature,” affected by ice cover for prolonged periods. “water temperature,” and “temperature” are synonymous throughout this report. Finally, the terms “station” and In addition to the above reports on graphical or “stream station” refers to locations where systematic analytical representations of seasonal variations in stream-temperature data are available; whereas, the term stream temperature, several other investigations warrant “site” and “stream site” refers to locations where little or mentioning. Detailed studies, generally on small no data are available. streams, have described and evaluated various environmental factors affecting stream temperatures

2 (Pluhowski, 1970; Moore, 1967). Collings and Stream-Temperature Data Higgins (1973) related stream-temperature harmonic Periodic and daily stream-temperature data for coefficients to selected characteristics of a basin using streams in Georgia stored in the USGS database through a multiple-regression approach and found the most 1984 were compiled for evaluation and possible further frequently occurring, statistically significant variables analyses. The compilation yielded 333 periodic stations were drainage area, channel slope, mean basin having 8 or more temperature measurements and 61 altitude, and mean annual streamflow. Gilroy and stations with daily temperature records. Of the 333 Steele (1972) evaluated the effects of reduced sampling periodic stations, 198 had five or more years of well- frequencies of stream-temperature measurements as distributed data suitable to determine long-term stream- depicted by harmonic coefficients for selected temperature characteristics (table 1, in back of report). long-term daily records. Similar criteria were used to screen the 61 daily record stations; 22 of these stations were selected as suitable Station-Identification System for harmonic analyses (table 2, in back of report). All The stream-temperature station numbers are but four of the daily record stations (02208450, based upon a numbering system which has been used 02231000, 02338660, and 02382720, respectively) also for USGS surface-water stations since October 1, 1950. are periodic stations. The 198 periodic stream- In this system, the station-identification number is temperature stations selected for analysis are listed in assigned according to downstream order and gaps table 1 with their locations shown in figure 1. The 22 are left in the series of numbers to allow for new selected daily stream-temperature record stations are stations that may be established; hence, the numbers listed in table 2 and shown in figure 1. The figure also are not consecutive. The complete number of each shows major river basins and physiographic provinces station, such as 02331655, includes the two-digit part discussed in this report. number “02” plus the downstream-order number Periodic stream temperatures for stations listed in “331655,” which can be from 6 to 12 digits (Stokes table 1 were measured by holding a thermometer in and McFarlane, 1995). The tables and most figures in flowing water and, in most instances, reading the this report adhere to this system. thermometer while the bulb was immersed. Accuracies In figures 1 and 2 of this report, the USGS of periodic temperature measuring techniques used by stream-station numbers are shortened by omitting the the USGS are within about 0.8 ° C (Moore, 1967, first two digits. Similarly, in the text of this report, all p. 8–14; Rawson, 1970, p. 2–4; Blodgett, 1970, p. 2–3). stream-temperature station names that are referenced to Because most periodic-temperature measurements are Georgia cities are shortened to omit the “Ga.” part. For made during daylight hours, observed stream example, the complete station number and name for the temperatures generally are higher than daily mean abbreviated “392500, Little River near Roswell,” is stream temperatures. “02392500, Little River near Roswell, Ga.” Other Daily record stream temperatures were collected abbreviated station numbers can be completed similarly by automatic recording equipment or by local observers. with the exception of stations having abbreviated A variety of automatic recorders have been used to numbers greater than 5000—these stations require a collect data over the years. Generally, accuracies of leading “03” rather than a leading “02.” For example, water temperatures collected by automatic recording the complete station number for station 545000 is equipment are within ± 1 ° C (Moore, 1967, p. 8–14; 03545000. The number and name abbreviations are Rawson, 1970, p. 2–4; Blodgett, 1970, p. 2–3). Data intended to improve the readability of the report. The collected by local observers also are believed to be tables and most figures in this report contain complete within ± 1 ° C. station numbers and names.

3 TENNESSEE RIVER BASIN

° 35° 85 84° 566800 560000 553500 545000 EXPLANATION 567340 559000 550500 178400 384748 558000 Major river basin boundary VALLEY AND 177000 385800 380000 BLUE 387000 379500 Physiographic province boundary RIDGE RIDGE 182000 388000 387500 387050 380500 331000 382500 189050 387502 383500 189100 Stream temperature station and 398000 383540 333500 189500 190200 83° 382000 331600 190100 189600 190500 identification number COOSA RIVER BASIN 190000 398037 383000 389300 191000 388500 389000 191200 191000 Periodic 388520 396000 392000 187500 208450 397530 395000 Daily 217000 188500 397000 394000 219500 394980 334500 Periodic and daily 394950 S 392500 335700 A 34° 397500 V 189000 335000 205000 217740 A 217500 N 192000 336000 206500 218000 N 411800 336502 336300 A 337000 PIEDMONT H 411930 337170 337100 203800 207300 R 208450 219500 IV 337438 203965 207500 193500 E 344180 207540 413210 218500 R 82° 337500 344300 204285 204500 209260 B 338000 344190 204520 221000 A 196820 344380 208005 220550 S 344700 I 197000 338500 344400 210500 197520 N

211300 O 197600 344500 A G 197830 339000 212600 L E T Line E 33° 338720 A C 213050 M 223040 H 198000 197500 339720 E

N 212950 A 339500 I 346500 213470 H E

S 223300 –

213000 A 223250 N A 340500 347500 213500 223000 E 202000 B R W 213700 Fall I V P R O E E 223500 R 214265 R V T 202190 198500 341500 I 223600 349000 214500

R 224000 B R 341800 A IV N E S I 349500 E I R E S N 202500 H A 349900 B 225470 C A B 203000 S 81° O 225500 350600 350001 COASTAL PLAIN IN O 32° R S H E 215260 203519 A V T343200 I 215500 225000 T 203559 R A 203566 203570 H 203578 T 225990 203574 C 226000 203585 N I 352500 226010 203596 L 227000 353400 F 226100 352790 317800 317718 SATILLA–ST MARYS 226160 353500 RIVER BASINS 227500 316000 226475 353000 343500 226500 226582 228000

344000 327205 318000 357000 SUWANNEE–OCHLOCKONEE–AUCILLA 31° 344040 RIVER BASINS 356000 356015 317749 327500 317757 328000 318725 318500 317500 231000 328200 318960 314500 Base from U.S. Geological Survey digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 1. Locations of 198 periodic and 22 daily stream-temperature stations, major river basins, and physiographic provinces in Georgia.

4 ° 35° 85 84° r N T

567340 R J o a 566800 C a 560000 t l

a a T te l u EXPLANATION r c o

g a g c ly k l 545000 l

C l u u c R a s R a u a o

a h a g s R a h g

u a m R o a a R 178400 n o

a o t m k o r t

a c C C a k i C ly h Major river basin boundary ic h l C h C o r C L 384748 H C 177000 ck 380000 558000 W o R T 379500 u Physiographic province boundary 385800 ga wattee R lo sa Carte R o 387500 o 380500 cay R 331000 R o iv t e s R C 382500 r a la N 192000 Stream temperature station and E u 383500 331600 o R398000 a r 83° n th a a 333500 g t e identification number r s

o e r H M o o t t C i

a e d

O u t F t d a v l

s d i e o h s e

R F r C o o k h n rk 389000 C R r iv sa e er Coo r r iv 191200 e R A B iv C ll e R l h en a a a C v E N e C o u w 392000 r rd e h t o M S d O a a S L m i S i d c a r tt o C le d o u re v l n e

R e th k a C e O r e F n r C o e c B ig o R rk r n e B n o a k e a 34° 335700 e d h R River R 217500 217740 192000 iv A A e a River p os lc a r po 206500 o la

a r Cree v c 218000 e y h O ll at k e w Y

a et P e c e

T e ea o

chtr Cr l w ee n l S o

w e

337000 e

R D 411930 o R R

g ver a C i i i

s v v R

r e o S e S r

o o 207300 r Lit p n u tle a a t ll h a k T e 337438 R 219500 R C L 193500

R i i tt

e a v le R

Little C i ° m e

e r v 82

r i

p e

h v O

c r C e

r g B o r 413210 r u o e t C 204520 l h B e e r r a e Rum 209260 ier Cr t n C c t i r L T M h a ow u C e al O r r

h ig d e

c a e 197520 e e

m r C C k

344700 u r F e l e k g

e a k B e e r l r C l u i

e s t n ke 344500 hy r Cre

c g C ek ja R

w i C R o v r ll er i Ye v k e e Line r 197830 339000 e r S B To r r C b 212600 w ie C e W r ° o s a e a 33 n t o m a a f l O C n p g t k C e u n F o c k e o

o t e P m o

L e l r C C 339720 C i m n C l n E r e

a r is r o ch e s e h t e e io e S co n L ek 198000 at 346500 n k er it Fl ne Cr tle O C e eek gee reek

Bi c g R h O e

i O g

340500 v Sa e 347500 n e h d e ry C C y r o r r C O c e re r o b e h h ul k oo p M pe e e Fall e e e R R C R r S R i e M v i e a i v k i o e R v e v s o e v s r c T a W y k u r r e y R n Cree h C r i k r C k v i re e n te e re e y r C w B k ek 223500 a a ig C a h t r n 202190 e P o r e o toi C Indian L n pa 349000 Cr d c L R U r it O e h e t c lt o e l o e t L i e o t U 214500 n n e v k s o e R p O e C w e i c v r p e r m e e e r e r u r C k l r g e e B e O k l 349500 e r a 202500 M h e r c o 203000 v u C A k l o i c liga k y p C

R a e to r e r

le k C 349900 r r e e u 225470 Ca T R n O L ° R o 81 i o O i v c g 350600 M ve h g e u r e e e r e e c 225500 e c k c h a e ° K h e 32 i l R River n o e R

c A i o lt h am v e c a a O h e f h a R o e c r

k Ic o P e h n e m e a 225000 r e u e C w e C 215500 343200 l a M r g a e C e c y e o d

n r w e

P r R c a

a o iv H k

la e er y C R C C

c c u r u k N h R

a h r

t r i e r i v

e a a i t c B N P l e e e a w a i e

h k n g L r a w

e C c S S p

y t H S W Little C a ort

r a i u a

e lla r ti ti 226000

h S r e ll l e c r a l

w o ic e a k N R o a a R rt a c k ewpo n s h t e a e i C A l 226100 lo R e pe k l C r Sa c l a e ay i w C

e a r e r R 227000 o T L l

h p k e i o

y t i

C a h t v l h n

h W a T e 353400 e

N R e

y

c i r e v P a R r e w o r i r e r v

i C o e v o 227500 226160 r h i r r

e A l R C e a a b

r k t 353500 e 316000 a t e R h

C R lla a k i r a ti

v A ive Sa

r e R l

h e

r a e

p Turtle

C k

S C a

O r L p h

k r

r a

O r 228000 i a e n

c L p v g e i S S

h i u a

h l R w till a c l g o a v o n R

u c i ee

lo k

357000 S o R

n

e e C

° C er 31 R r v

r g e i e i B e R

e e k k e t T h

c R n ir

e o

i i l d o v C

c S e r F C

e r la S e r u e t r e ith v M 328000 n 327500 e w i a A k W 317757 R ry ko u a s R c c no iv o il 318500 oc e er l l hee C e ch a r n R n O a w 317500 u 314500 Base from U.S. Geological Survey S digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 2. Names of major streams and locations of 78 stream-temperature stations used to compute harmonic stream-temperature regression equations.

5 LONG-TERM STREAM-TEMPERATURE t is the time of year expressed as a day number, CHARACTERISTICS where t = 1 for October 1; and Dyar and Stokes (1973) demonstrated that annual c is the phase coefficient of the harmonic seasonal or long-term stream-temperature function. characteristics may be represented by a harmonic A generalized example of a harmonic temperature (sinusoidal) function of the following form (Ward, 1963; curve computed from equation (1) is shown in figure 3. Collings, 1969; and Steele and Gilroy, 1972): Harmonic coefficients for equation (1) (M, A, and c) T = M + A [sin (b t + c)] (1) may be determined by plotting stream-temperature station data for the selected period of analysis on a where single annual time segment, without regard to year, T is the harmonic-mean stream temperature on and computing the least-square harmonic fit from the day “t”; data points. The selected annual time segment is a M is the harmonic-mean coefficient or the long- standard “water year” used by the USGS, which term mean stream temperature for the period represents a period of October 1 to September 30 of of record used in the analysis; the following calendar year. A is the amplitude coefficient or annual range Stream-temperature data for each station listed in in temperature of the harmonic function (or tables 1 and 2 were plotted and harmonic-function one-half the estimated annual variation in coefficients were computed from a least-squares stream temperature for the period of record); sinusoidal fit of the data. The computed coefficients, standard errors, and variances are listed in tables 1 and b is a constant to convert time of year “t” to 2. Multiple analyses were performed for six periodic degrees of arc;

45 110

40 Harmonic equation T= M + A[sin(bt + c)] ° 2 100 T( Celsius)=13.2 + 8.4[sin( 365 t + 2.69)] 35

90 30 Stream- temperature measurement 80 25 Harmonic function 70 20 C=Phase angle=2.69 Radians 60 15 M=Mean annual=13.2°C

10 A=Amplitude=8.4°C 50

5 WATER TEMPERATURE (T), IN DEGREES CELSIUS 40 WATER TEMPERATURE (T), IN DEGREES FAHRENHEIT

0 OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEPT DAY OF THE WATER YEAR (t) Figure 3. Generalized harmonic stream-temperature curve showing harmonic equation coefficients.

6 stations (02213500, 02318000, 02336000, 02339500, b0...n are terms of regression coefficients; and 02392500, and 02394000) because reservoirs x1...n are variables of selected basin character- constructed upstream from the stations during the period istics considered in the regional analysis. of record interrupted the homogeneity of the tempera- ture data. Graphs of the annualized stream-temperature Independent variables used for the regression included data and harmonic-function curves for selected periodic the station latitude, drainage area, and altitude (table 1). stations listed in table 1 are shown in back of this report. Harmonic Mean Coefficient Natural Stream-Temperature Characteristics The empirical equation resulting from the regression analysis to estimate the natural long-term To estimate natural stream-temperature harmonic mean stream-temperature coefficient characteristics at ungaged locations, 78 of the 198 applicable throughout the State of Georgia is: periodic stream-temperature stations were selected for regression analysis. No continuous-record stations were M = 42.68 - 0.833 * L + 0.743 * log D - 0.00133 * E (3) selected for analysis because most were located on where modified streams or were already represented by M is the long-term mean stream periodic stations at the same locations. Stations with temperature or the harmonic mean stream temperatures substantially affected by human temperature coefficient, in ° C; activities and stations having drainage areas less than L is the station or stream location latitude, 40 square miles (mi2) were excluded from analysis. To in decimal degrees; help ensure statistical independence, most mainstem stations were excluded. However, 16 stations with D is the station or stream location drainage drainage areas greater than 1,000 mi2 were included to area, in square miles; and provide sufficient drainage area variability for the E is the station or stream location altitude, regional analysis. The 78 stations selected for analysis in feet above sea level. are listed in table 3 (in back of report) and their locations and stream names are shown in figure 2. Harmonic mean stream-temperature and indepen- dent variable data used in this regression equation are Several limitations of the data used to compute listed in table 3. The regression yields a standard error natural temperature characteristics should be noted. of about 0.4 ° C for the harmonic mean stream- First, for the analysis to be rigorous, only stations temperature coefficient. Equation (3) accounts for having completely natural conditions upstream 95 percent of the variance, with the latitude component should be used. Because some modifications have accounting for about 49 percent; altitude for about occurred on most major streams, computation 27 percent; and drainage area for about 19 percent. of completely natural temperature characteristics was Harmonic mean temperatures tend to increase not possible. However, natural stream-temperatures southward and with lower basin altitude. should predominate at each of the 78 stations used for analysis (table 3). Second, most periodic data Residuals obtained by subtracting harmonic mean collection occurs in daylight hours, causing a slight temperatures determined by regression equation (3) temperature bias. This bias typically is from about from the values calculated by harmonic analyses of 0.5 to 1 ° C or less; most bias occurs on smaller station data are shown in figure 5. Negative values streams during the warmer seasons. indicate harmonic mean temperatures computed from station data are less than those determined by equation Regression Analysis (3). Clusters of both negative and positive residuals are To develop regional relations, the harmonic mean apparent in figure 5; at least one of the larger departures (M), amplitude (A), and phase coefficients (c) listed in shown in figure 5 is relatively easy to explain. West table 3 were each analyzed by regression analyses; the Chickamauga Creek near Lakeview (station 03567340) following multiple-regression function was defined: has a residual value of + 1.0 ° C as would be expected for any stream in Georgia that flows opposite to the y = b + b * x + b * x + b * x + . . . + b * x (2) 0 1 1 2 2 3 3 n n primary north-to-south direction. However, for the most where part, the map of residuals (fig. 5) shows random and y is one of the harmonic-analysis small numerical departures from equation (3). coefficients (M, A, or c as defined in equation 1);

7 ° 35° 85 84° 15.3 14.8 13.5 12.7 EXPLANATION 12.0 15.1 12.9 Major river basin boundary 13.6 13.6 14.7 Physiographic province boundary 15.1 13.7 13.9 13.9 Harmonic mean temperature, in 15.0 15.2 83° 16.4 14.1 14.7 15.6 degrees Celsius

13.6 14.3 14.2

14.3 34° 14.8 15.5 16.4 14.6 15.4 15.4 15.3 15.1 15.1 16.0 15.3 82° 15.6 15.6 15.4 15.3 15.3 16.0 17.0 15.6 15.4 Line 33° 16.4 16.1 16.7

17.6 15.4 Fall 18.0 17.0 17.6 17.1

18.0 18.3 17.2 18.0 17.7 81° 16.9 18.5 32° 17.0 19.0 19.3

19.4

17.3 17.9 18.4 18.9 19.7 18.4 18.6 20.0

18.2 31°

17.7 18.4 18.5 18.9 19.6 19.9 Base from U.S. Geological Survey digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 4. Harmonic mean stream temperatures for 78 natural-condition stations.

8 ° 35° 85 84° 1.0 0.5 0.5 0.4 EXPLANATION –0.4 0.4 –0.1 Major river basin boundary 0.0 –0.3 0.5 Physiographic province boundary –0.2 0.2 0.1 0.0 0.0 0.4 Harmonic mean temperature –0.5 83° 0.1 0.2 residual, in degrees Celsius 0.7 –0.2 –0.5 –0.9

–0.1 34° –0.6 0.2 –0.4 –0.1 –0.5 0.2 0.1 –0.4 0.3 –0.1 –0.7 0.3 –0.5 82°

–0.5 –0.4 –0.1

0.1 –0.4 0.2 –0.6 Line 33° 0.2 –0.8 0.5 –0.6 0.2 Fall –0.1 0.2 –0.4 0.5

0.0 –0.1 –0.1 0.6 0.4 81° –0.3 0.4 32° –0.2 0.3 0.3

0.0

0.3 –0.5 0.1 0.4 0.1 0.0 0.2

0.8

–0.5 31°

–0.3 –0.4 –0.4 –0.4 0.3 0.6 Base from U.S. Geological Survey digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 5. Residuals of harmonic mean stream temperatures for 78 natural-condition stations.

9 Natural long-term temperature anomalies can be Residuals computed by subtracting amplitude expected in some locations in Georgia. For example, coefficients computed by equation (4) from the values stream temperatures in and around Warm Springs, likely computed from station data are shown in figure 7. The would be higher than values predicted by equation (3). residuals in figure 7 range from an average of about +0.6 Along the coast and in tidal streams (such as stations ° C in the Piedmont Province to an average of about -0.3 02203559, 02203566, 02203570, 02203574, ° C for much of the remaining provinces in the State; 02203578, 02203585, and 02203596), data are scarce. this indicates that equation (4) tends to underestimate Because stations having sea affects are not included, the harmonic amplitude coefficient in much of the equation (3) should not be applied to tidally affected Piedmont, and to overestimate it throughout most of the stream sites. Stream locations having drainage areas remainder of the State. Much of the difference in the smaller than about 40 mi2 or having a very high amplitude coefficients in the two areas may be proportion of streamflow derived from ground-water attributable to natural causes. Many of the negative inflow upstream may show deviations of 1 ° C or residuals occur on streams having large components of more from values estimated by equation (3). ground-water inflow. For example, a relatively large The empirical equation used to estimate natural proportion of streamflow at Whitewater Creek near long-term harmonic-mean temperatures in Georgia Butler (station 02349000), having one of the largest streams predict a maximum high value of about negative residuals of -1.8 ° C, comes from ground-water 20.5 ° C; such values occur at lower latitudes, lower inflow. The large ground-water component also applies altitudes, and in larger drainage basins. The minimum to the Chattooga River at Summerville (station predicted low value is about 12.3 ° C; values in this 02398000). range occur at higher latitudes, higher altitudes, and in Many streams immediately south of the Fall Line smaller drainage basins. Generally, the harmonic mean also have relatively large components of ground-water temperatures computed from data for the 78 stations inflow, as do those in the southern parts of the analyzed (table 3) agree well with those estimated by Chattahoochee and Flint River basins in southwestern equation (3). Georgia, and in some of the Valley and Ridge Province within the Coosa River basin. Conversely, the high Amplitude Coefficient positive residuals seen at stations in the southern Piedmont Province may be attributable to relatively The empirical equation resulting from the small ground-water inflow to these streams. Also, the regression analysis to estimate the natural long-term band of positive residuals within the Piedmont is amplitude stream-temperature coefficient applicable coincident with high population densities and may be throughout the State of Georgia is: partially attributable to affects of human development. A = -7.40 + 0.947 * log D + 0.426 * L - 0.00075 * E (4) Estimates of long-term natural harmonic amplitude where coefficients from equation (4) can yield a range of A is the amplitude coefficient in ° C; amplitude from a high value of about 11.2 ° C to a low D is the station or stream location drainage value of about 5.0 ° C for normal variations of the area, in square miles; independent variables. High values typically occur with larger drainage areas, higher latitudes, and lower L is the station or stream location latitude, altitudes. Low values tend to occur with smaller in decimal degrees; and drainage areas, lower latitudes, and higher altitudes. E is the station or stream location altitude, However, higher altitudes do not occur with lower in feet. latitudes in the State. From table 3, the maximum long- term natural harmonic-amplitude coefficient is about Amplitude and independent variable data used in 10.2 ° C for the Flint River near Culloden (station equation (4) are identified in table 3. An areal plot of 02347500). The minimum amplitude coefficient the amplitude coefficients is shown in figure 6. The observed from the 78 stations analyzed is about 6.2 ° C regression yields a standard error of about 0.7 ° C. for Whitewater Creek near Butler (station 02349000) Equation (4) accounts for about 48 percent of the (table 3). variance, with the drainage area component accounting for about 18 percent; latitude for about 18 percent; and altitude for about 12 percent.

10 ° 35° 85 84° 8.5 9.0 7.9 6.5 EXPLANATION 8.1 7.2 Major river basin boundary 9.9 9.2 8.0 9.0 Physiographic province boundary 9.6 8.0 7.5 8.4 Amplitude coefficient, in 9.8 9.4 83° 9.6 7.9 8.7 degrees Celsius 7.2

8.2 8.2 8.9

7.8 34° 9.6 9.4 9.6 9.1 10.0 9.4 9.4 9.3 8.9 9.2 9.5 82° 9.2 9.1 9.3 7.6 9.8 10.0 9.3 Line 8.4 8.2 33°

9.0 9.8 8.9

10.2 9.1 Fall 9.3 7.7 10.0 6.2

9.0 9.3 7.3 8.8 8.9 81° 8.0 9.1 32° 6.8 9.9 10.1

10.0 8.4 7.2 8.0 9.3 8.4 7.6 8.1 9.1

8.1 31°

7.4 8.6 8.3 9.0 8.5 8.5 Base from U.S. Geological Survey digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 6. Amplitude coefficients for 78 natural-condition stations.

11 ° 35° 85 84° –0.5 –0.2 –0.3 –1.1 EXPLANATION –0.5 0.6 –0.1 Major river basin boundary -0.3 0.5 0.4 Physiographic province boundary –0.9 –0.1 0.2 –0.7 –0.1 Residual of amplitude coefficient, –0.2 83° –0.2 –0.6 –0.1 in degrees Celsius –1.8 –0.2 –0.2 –0.3

–0.3 34° 0.7 0.3 –0.2 0.7 0.6 0.8 0.8 0.6 0.9 0.1 0.5 0.2 82° 0.7 0.5 –0.6

1.7 1.5 –0.9 0.2 Line 33° 0.9 –0.3 1.0 1.5 0.8 1.3 Fall –0.5 –1.8 –0.4 0.4

–0.4 –0.3 0.1 –0.2 0.2 0.0 81° –0.2 32° –1.0 0.3 0.1

0.0

0.4 –0.8 –0.2 –0.6 –0.2 –0.9 –0.4 0.0

–0.2 31°

0.1 0.1 0.4 0.3 –0.1 0.0 Base from U.S. Geological Survey digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 7. Residuals of amplitude coefficients for 78 natural-condition stations.

12 The amplitude coefficient of the harmonic function L is the station or stream location latitude, is useful to determine the high and low stream- in decimal degrees—values ranging temperature regimens, as illustrated by figure 3. Graphs from about 30.5 degrees to 35 degrees; and data included in this report show that the addition of D is the station or stream location drainage the amplitude to the harmonic mean temperature area, in square miles—values ranging provides estimates of average annual maximum stream from about 40 to 14,000 mi2, temperatures. Similarly, subtraction of the amplitude from the harmonic mean yields estimates of average E is the station or stream location altitude, annual minimum temperatures. in feet—values ranging from about 0 to 2,000 feet; and Phase Coefficient t is incremented day-by-day beginning Regression analyses were applied to phase- with “1” for October 1 to “365” or “366” coefficient data in table 3. No basin or hydrologic for September 30 of a given or leap year, parameters were found to be helpful in determining the respectively. value of the phase coefficient. The natural long-term The insertion of latitude, drainage area, and phase coefficient is a constant of about 2.81 radians. The altitude values into equation (5) while incrementing “t” standard error of the phase coefficient is about 0.04 day-by-day throughout a year generates a harmonic radians, amounting to about two days. Long-term mean- curve which tends to provide a good description of temperature values are most likely to occur in natural stream-temperature response to solar radiation, season streams in Georgia on about October 19 and April 20. by season, throughout the State. Minimum and maximum long-term natural temperatures are likely to occur on about January 19 and July 20, The harmonic mean and amplitude coefficients respectively. Temperatures near the annual maximum that are generated by equation (5), hereinafter termed and minimum are likely to persist for several weeks. For the “statewide harmonic equation,” match the individual example, temperatures within 1 ° C of the maximum harmonic stream-temperature coefficients for the 78 temperature are likely to occur from about the end of natural-condition stations to within an average of about June through mid-August. Similarly, temperatures 0.4 ° C. When equation (5) is applied to the stream- within 1 ° C of the minimum value are likely to occur temperature measurements of the 78 regression-analysis from about the end of December through mid-February. stations shown in table 3, the data mostly appear as The individual phase-coefficient values for each of the normally distributed about each curve. The standard selected 78 stations are plotted on figure 8, indicating error or natural temperature scatter averages about 2.2 ° that the phase-coefficient data are adequately described C (table 3) throughout the State. Likewise, the 95 by the constant of 2.81 radians. percent probability averages about 1.2 ° C above or below the applied statewide harmonic curve. Because Statewide Harmonic Equation of the uniform scatter of data about the applied harmonic curve and the large number of data Long-term stream-temperature characteristics measurements used in the computation, upper and lower commonly are estimated for sites when stream- bounds in these ranges should give the data user an temperature data are not available or are not practical estimate of natural statistical temperature ranges. to obtain. The harmonic equation to estimate long-term natural stream-temperature characteristics in Georgia is The statewide harmonic equation was derived from derived by substituting equations (3) and (4) and the 78 stations having drainage areas greater than about 40 2 constant of 2.81 radians into equation (1). The resulting mi , using temperature data collected from about 1955– equation to estimate long-term natural stream- 84 (table 3). Derivations using other periods of analysis, temperature characteristics is: subsequent data, or different stations could cause somewhat different results. T = 42.68 - 0.833 * L + 0.743 * log D - 0.00133 * E + (0.947 * log D + 0.426 * L - 0.00075 * E - 7.40) * To evaluate the suitability of the statewide 2 (sin (2 * π * t/365 + 2.81)) (5) harmonic equation for drainage areas less than 40 mi , 13 stations having drainage areas ranging from 15 to 37 where mi2 and having mostly natural stream-temperature T is the estimated long-term mean-daily characteristics were selected from table 1. For the 13 stream temperature in ° C for the selected stations, the statewide harmonic equation selected day of the year; yielded average harmonic temperature coefficients

13 ° 35° 85 84° 2.77 2.79 2.82 EXPLANATION 2.81 2.78 2.77 2.77 Major river basin boundary 2.82 2.80 2.75 Physiographic province boundary 2.76 2.79 2.77 2.77 2.77 Phase coeffcient, in radians 2.78 83° 2.82 2.76 2.82 2.74 2.74 2.80

2.81

2.78 34° 2.90 2.82 2.80 2.82 2.85 2.83 2.85 2.86 2.84 2.79 2.85 2.78 82° 2.80

2.83 2.76 2.79 2.85 2.85 2.86 Line 2.78 33° 2.83 2.89 2.80 2.82 2.83 Fall 2.69 2.84 2.90 2.87

2.87 2.81 2.91 2.92 2.85 81° 2.91 2.78 32°

2.88 2.76 2.78

2.75

2.90 2.95 2.82 2.71 2.82 2.82 2.78

2.77

2.81 31°

2.81 2.77 2.75 2.77 2.78 2.83 Base from U.S. Geological Survey digital files 0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 8. Phase coefficients for 78 natural-condition stations.

14 within about 0.7 ° C of the coefficients computed from Examples of Estimating Natural observed data. This error of prediction for harmonic Stream-Temperature Characteristics temperature coefficients is higher than the 0.4 ° C Four examples illustrating uses of stream- average error computed using the 78 larger drainage temperature data and regression equations presented in area stations from table 3. Though the statistical sample this report are described below. The stations selected of 13 stations is small and confined to central and for discussion range widely in size and geographic northern Georgia streams, the statewide harmonic location and include (1) Panther Creek, a small stream equation is expected to generate progressively larger in the upper reaches of the Savannah River basin in the errors of prediction for drainage areas less than about Blue Ridge Province; (2) West Armuchee Creek in the 15 mi2. More discussion of applications and limitations Coosa River basin in the Valley and Ridge Province; of the statewide harmonic equation is presented in (3) Alcovy River in the Altamaha River basin in the following sections of this report. Piedmont Province; and (4) Altamaha River about Harmonic statistics of the daily stream- 60 miles upstream from its mouth and in the Coastal temperature records (table 2) show that long-term Plain Province. Each example depicts how a user harmonic curves of daily maximum and minimum might choose to analyze and estimate natural stream- stream temperatures, typically range from about 1.0 to temperature characteristics at the site of interest. 1.5 ° C above and below, respectively, the long-term Although each example of estimating natural long-term harmonic mean curve for stations having drainage areas stream-temperature characteristics described below of about 100 mi2, and about 0.5 ° C above and below was selected for a stream having available stream- the long-term mean curve for stations having drainage temperature data, similar procedures could be used to areas of about 10,000 mi2. Addition (or substraction) of estimate temperature characteristics at ungaged sites. these values to equation (5) and the analysis of Also, it is important to note that each example relies on maximum or minimum monthly observed values from historical data through no later than 1984 that may or nearby data can produce good estimates of expected may not accurately reflect current or future stream- maximum or minimum stream-temperature values for temperature conditions. any month of the year. There are some asymmetrical properties of annual Panther Creek stream-temperature characteristics which the sinusoidal The first example illustrates how a user can fitting process tends to obscure, such as when minimum compare station data with the statewide harmonic temperatures approach freezing. Stream temperatures equation. Panther Creek near Toccoa (station that approach 0 ° C do not fit a sinusoidal distribution. 02182000) has 75 temperature measurements made Perhaps a more important asymmetrical stream- between 1959-74 (table 1). Harmonic coefficients and temperature consideration at a station comes from heat curves computed from station data and from equations flux proportional to streamflow. The annual heat-flux (3), (4), and (5) appear in figure 9. The drainage area of distribution is skewed because runoff typically this station is 33 mi2, somewhat less than the 40 mi2 increases, particularly in natural streams, during the regression equation criteria. Nonetheless, coefficients colder December-April period. Examples of this derived from observed data are very similar to phenomenon can be observed in stream reaches below coefficients computed from the statewide harmonic some reservoirs. The reservoirs act as heat sinks that equation (fig. 9). The two curves in figure 9 show that tend to moderate and lag downstream temperatures. natural temperatures for 1959-74 averaged about 1 to 2 ° When reservoir storage is large compared to average C higher than temperatures computed by the statewide annual stream runoff, downstream stream-temperature harmonic equation. characteristics may be markedly changed from natural temperature characteristics. For example, the annual West Armuchee Creek mean harmonic-stream temperature downstream of This example illustrates the use of nearby data to Lake Sidney Lanier (Chattahoochee River near Buford, improve temperature-characteristic estimates. West station 02334500) currently is about 9.2 ° C, which is Armuchee Creek near Subligna (station 02388000) about 6 ° C below the natural annual harmonic-mean appears in table 1 with harmonic coefficients and a temperature—calculated from equation (5) for the drainage area of about 36 mi2. The comparison of the station—of about 15.3 ° C. Because near-bottom water harmonic coefficients from actual data and the statewide is released from Lake Sidney Lanier, the Chattahoochee harmonic equation is shown in figure 10. The harmonic River downstream from the lake has temperature stream-temperature characteristics curves are about the characteristics of the cool season throughout the year. same, except for the period October through March 15 40 100 Computed from 35 Statistic Data Equation 5 Line Symbol 90 Harmonic Mean 13.2 14.0 30 Amplitude 8.4 8.3 Phase Coefficient 2.69 2.81 Standard Error 2.10 80 25 Percent Variance 86.1 Measurements 75 Observed water temperature 70 20

15 60

10 50

5

WATER TEMPERATURE, IN DEGREES CELSIUS TEMPERATURE, WATER 40 WATER TEMPERATURE, IN DEGREES FAHRENHEIT TEMPERATURE, WATER

0 Observed OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEPT Maximum 16.5 13.0 10.5 5.5 8.0 11.5 16.5 19.0 21.5 25.5 24.0 23.5 Minimum 13.0 6.5 2.0 1.0 6.0 5.5 7.0 11.5 16.0 18.5 19.5 16.0 Figure 9. Harmonic stream-temperature curves of observed data and statewide harmonic equation for Panther Creek near Toccoa, Georgia (station 02182000), September 1959 to June 1974.

40 100 Computed from 35 Statistic Data Equation 5 Line Symbol 90 Harmonic Mean 14.8 14.0 30 Amplitude 7.2 8.2 Phase Coefficient 2.76 2.81 Standard Error 1.82 80 25 Percent Variance 85.4 Measurements 156 Observed water temperature 70 20

15 60

10 50

5

WATER TEMPERATURE, IN DEGREES CELSIUS TEMPERATURE, WATER 40 WATER TEMPERATURE, IN DEGREES FAHRENHEIT TEMPERATURE, WATER

0 Observed OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEPT Maximum 19.5 16.5 12.0 9.0 12.0 15.0 18.0 20.0 24.5 24.0 24.0 24.5 Minimum 10.0 10.0 5.0 5.5 4.0 8.5 12.0 13.0 18.0 20.0 18.0 17.0 Figure 10. Harmonic stream-temperature curves of observed data and statewide harmonic equation for West Armuchee Creek near Subligna, Georgia (station 02388000), May 1960 to April 1982.

16 when the statewide harmonic equation yields about 1 to Altamaha River 2 ° C lower values. Because of differences of several The Altamaha River near Gardi (station 02226010) degrees in the two characteristic curves during the cold in the Coastal Plain Province also was selected as an weather months, it is helpful to examine temperature example to estimate long-term natural stream- characteristics at other nearby stations. Stations temperature characteristics. Following the procedures 02397500, 02398000, 03566800, and 03567340 are outlined above, the data user will recognize that the site nearby stations within the same Valley and Ridge has 113 recorded temperature measurements (table 1). Province (figs. 197, 199, 210, and 211), and all show a To independently estimate the long-term natural stream- similar deviation from the statewide harmonic equation temperature characteristics at this station, an during the cooler months. Therefore, the data user may interpolation of harmonic characteristics from a nearby consider this characteristic to be a local anomaly for upstream station, Altamaha River at Doctortown (station stations in nearby streams in the Valley and Ridge 02226000) and a nearby downstream station, Altamaha Province. Better estimation of stream-temperature River at Everett City (station 02226160) is performed characteristics may require adjusting the coefficients and shown in table 4. from the statewide harmonic equation to more closely reflect local conditions. The reach of the Altamaha River from Doctortown In general, when using data from nearby stations to to Everett City does not have substantial tributary inflow improve estimates of natural stream-temperature or modifications that would significantly alter long-term characteristics, streams having similar flow thermal characteristics during the period selected for characteristics should be selected. For example, within analysis. Interpolated and observed values compare well the Coosa River basin, stations from the Valley and with the harmonic mean coefficient, showing the largest Ridge Province in the western part of the basin show difference of 0.3 ° C between interpolated data differing low-flow characteristics than stations typically (19.6 ° C) and computed from observed data (19.9 ° C) representative of the Piedmont Province to the east. (table 4). The 1970–84 temperature data at the Therefore, some local variations in long-term stream- downstream station, Altamaha River at Everett City temperature characteristics within the Coosa River basin (station 02226160), generates a slightly higher harmonic can be expected. mean temperature than either the statewide harmonic equation for the Gardi station or the observed record at Alcovy River Doctortown. The interpolated harmonic mean coefficients (table 4) were averaged from the upstream This example determines the long-term natural and downstream stations, rather than to more heavily stream-temperature characteristics for a site in the weight the coefficients from the closer upstream station. Piedmont Province—Alcovy River above Covington (station 02208450). A search of the USGS database Using the coefficients computed from observed yielded 27 stream-temperature measurements for data as a basis, it appears that the interpolated example Alcovy River above Covington from 1972–75. furnishes better estimates than those obtained from the However, because of the short period of record, statewide harmonic equation. Comments concerning harmonic computations are not shown in table 1. (A tributary inflow, analysis of the stream reach, and daily record station was maintained here for about 7 weighing effects of modification were included in the years; the information is summarized in table 2.) For example because each can be important to stream- this station, the input variables for the statewide temperature estimation within a stream reach. harmonic equation are as follows—latitude of about 33.64 degrees (decimal notation); drainage area of about 185 mi2; and altitude of about 650 ft. Figure 11 shows the 27 temperature measurements observed from 1972– 75, plotted on the annual cycle with the statewide harmonic equation superimposed. The data fit the equation well; and therefore, the data user may be reasonably confident that the data from the short period of record—about four years—is indicative of long-term natural stream-temperature characteristics at the station.

17 40 100 Computed from 35 Statistic Data Equation 5 Line Symbol 90 Harmonic Mean 14.9 15.5 30 Amplitude 8.3 8.6 Phase Coefficient 2.67 2.81 Standard Error 2.08. 80 25 Percent Variance 90.5 Measurements 27 Observed water temperature 70 20

15 60

10 50

5

WATER TEMPERATURE, IN DEGREES CELSIUS TEMPERATURE, WATER 40 WATER TEMPERATURE, IN DEGREES FAHRENHEIT TEMPERATURE, WATER

0 Observed OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEPT Maximum 15.5 13.0 7.0 12.5 9.5 11.9 12.0 21.0 24.0 25.0 22.0 25.0 Minimum 12.5 13.0 5.0 5.5 5.5 10.5 10.0 16.0 20.5 21.5 22.0 21.0 Figure 11. Harmonic stream-temperature curves of observed data and statewide harmonic equation for Alcovy River above Covington, Georgia (station 02208450), October 1972 to July 1975.

Table 4. Estimates of harmonic coefficients for Altamaha River near Gardi using interpolation and observed data compared with estimates from the statewide harmonic equation [mi2, square miles; ° C, degrees Celsius]

Period Drainage Harmonic Amplitude Phase Station Station name of area Type of data analysis mean (° C) coefficient number record (mi2) (° C) (radians) 02226000 Altamaha River at Doctortown 1937–79 13,600 observed 19.4 10.0 2.75

02226010 Altamaha River near Gardi 1974–84 13,600 observed 19.9 9.6 2.74 interpolated 19.6 9.6 2.73 statewide harmonic equation 19.4 10.0 2.81

02226160 Altamaha River at Everett City 1970–84 14,000 observed 19.7 9.3 2.71

18 SUMMARY OF Stream-temperature characteristics computed STREA M-TE MPERAT URE from observed data and from the statewide harmonic C H A R AC T E R I S T I C S equation for estimating natural characteristics for 26 BY RIVER BASIN stream-temperature stations within the basin are shown Many Georgia streams have reaches where in figures 14–39. Stream-temperature characteristics for stream-temperature characteristics are modified by five mainstem Savannah River stations are listed in human activities. For example, streams immediately table 2 and individual annual harmonic graphs are downstream from reservoirs or outflows from power- included in figures 17, 19, 33, 34, and 39. generating facilities typically exhibit modified stream- Hartwell Lake accounts for most of the modified temperature characteristics. Principal hydro-power and stream-temperature characteristics observed at thermoelectric-generating facilities in Georgia are Savannah River near Iva, S.C. (station 02187500) shown in figure 12 and listed in table 5. Similarly, (fig. 17). Compared to natural stream-temperature stream reaches often are affected by urban runoff, characteristics computed from the statewide harmonic waste water, and other discharges from large equation, the harmonic mean temperature is lowered by municipalities and industries. Cities and towns having about 2.8 ° C, the amplitude by about 4.9 ° C, the populations greater than 10,000 population according harmonic maximum temperature by about 7.7 ° C, the to the 1980 census (U.S. Department of Commerce, phase coefficient by about 0.64 radians (resulting in a Bureau of Census, 1982) are shown in figure 13. stream-temperature season lag of about one month), and Stream reaches receiving such discharges or runoff will the harmonic minimum temperature raised by about exhibit modified stream-temperature characteristics, 2.1 ° C. The downstream Savannah River station near depending upon the distance downstream and relative Calhoun Falls, S.C. (station 02189000) (fig. 19), shows amount of discharge to the flow of the receiving stream. some recovery toward natural characteristics. Stream- Selected stations in Georgia having natural and temperature records of both mainstem stations— modified stream-temperature characteristics are Savannah River at Iva, S.C. (station 02187500) and summarized by river basin and discussed in the Savannah River near Calhoun Falls, S.C. (station following sections. Graphical illustrations of harmonic- 02189000)—have historic value since both now are temperature characteristics computed from the inundated by Lake Richard B. Russell Reservoir. statewide harmonic equation for stations listed in table 1 The next mainstem station downstream from are shown in figures 14 through 211. Stream- Calhoun Falls is Savannah River at Augusta (station temperature characteristics in modified streams are 02197000). The Savannah River at Augusta station is more difficult to estimate than natural streams about 50.3 river miles downstream of Thurmond Lake because streamflow, chemical, and thermal and its record (1958-73) is indicative of the pre-Richard characteristics are undergoing changes from human- B. Russell Reservoir period through 1984. After induced activities. The following sections describing completion of Richard B. Russell Reservoir in 1983, streams by river basin are intended as an aid in some changes in downstream temperature estimating stream-temperature characteristics in natural characteristics are expected. and modified reaches, emphasizing modified larger stream reaches. Several other stations in the Savannah River basin show modified long-term stream-temperature Savannah River Basin characteristics. Six upper Broad River tributary stations and three mainstream Broad River stations—North Fork The Savannah River and its tributaries, the Broad River above Toccoa (station 02189050); Tugaloo and Chattooga Rivers, form the northeastern Denmans Creek near Toccoa (station 02189100); North boundaries of the State of Georgia (fig. 1). The basin Fork Broad River near Toccoa (station 02189500); Bear 2 drains about 10,580 mi of Georgia, South Carolina, Creek near Mize (station 02189600); North Fork Broad and North Carolina. Headwaters are in the River near Lavonia (station 02190000) Toms Creek near mountainous Blue Ridge Province and the principal Eastonollee (station 02190100); Toms Creek near flow is southeastward through the Piedmont and Avalon (station 02190200); Toms Creek near Martin Coastal Plain Provinces. (station 02190500); and North Fork Broad River near Carnesville (station 02191000) show characteristics

19

° 35° 85 84° EXPLANATION 553000 4999268 558500 Nottely Lake Major river basin boundary Blue Ridge Lake Burton Lake 178500 179500 Physiographic province 181570 179150 boundary 181650 Carters Lake 181600 381400 Electric generating plants 83° Hartwell and nearby USGS stream- Lake gage identification number 187250 397800 Lake Richard B Russell 187250 Hydro 393500 Sidney Lanier Reservoir 394140 189004 198745 Allatoona 334400 Thermo ° 394775 Reservoir 335810 34 1973269 Nuclear 336479 336480 218130 Thurmond Lake 194500 196360 207301 Lake 338030 Oconee 82° 207540 196627 196628 338330 Jackson Lake 220450 196630 210000 222247 Lake Sinclair 1973269 West Point 222500 Lake Lake 33° Juliette 212510 Line 339400 212890 339780 339820 Lake Fall Harding 341000 341300 341400 341420 341480 198745

198930 198977 81° 32° Lake 350390 Blackshear 222501 Walter F George Lake 350400

350550 343240 Lake Worth

352790

2261765

31° 343830

Lake Seminole

357500 Base from U.S. Geological Survey digital files 0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 12. Locations of principal power-generating facilities and major reservoirs in Georgia.

20 Table 5. Power-generating plants in Georgia [Modified from Fanning and others, 1991]

Station P la nt n am e Typ e/ Water source/ Year Capacity number Owner Fuel source Reservoir in service (kilowatts)

SAVANNAH RIVER BASIN

02178500 Burton Hydroelectric/ Tallulah River/ 1927 6,120 Georgia Power Company storage Lake Burton

02179150 Nacoochee Hydroelectric/ Tallulah River/ 1926 4,800 Georgia Power Company storage Lake Seed

02179500 Terrora Hydroelectric/ Tallulah River/ 1925 16,000 Georgia Power Company storage Mathis Reservoir

02181570 Tallulah Hydroelectric/ Tallulah River/ 1913 72,000 Georgia Power Company storage Tallulah Falls Lake

02181600 Tugalo Hydroelectric/ Tugalo River/ 1923 45,000 Georgia Power Company storage Tugalo Lake

02181650 Yonah Hydroelectric/ Tugalo River/ 1925 22,500 Georgia Power Company storage Lake Yonah

02187250 Hartwell Hydroelectric/ Savannah River/ 1962 344,000 U.S. Army Corps of Engineers storage Hartwell Lake

02189004 Russell Hydroelectric/ Savannah River/ 1984 300,000 U.S. Army Corps of Engineers storage Richard B. Russell Reservoir

02194500 Thurmond Hydroelectric/ Savannah River/ 1953 280,000 U.S. Army Corps of Engineers storage Thurmond Lake (formerly Clarks Hill Lake)

02196360 Stevens Creek Hydroelectric/ Savannah River/ 1914 18,900 South Carolina Electric and Gas Company run-of-river power pool

02196627 Sibley Hydroelectric/ Savannah River by Augusta 1920 2,100 Graniteville Company run-of-river Canal/none

02196628 King Mills Hydroelectric/ Savannah River by Augusta 1943 2,250 Division of Spartan Mills run-of-river Canal/none

02196630 Enterprise Hydroelectric/ Savannah River by Augusta 1920 1,200 Graniteville Company run-of-river Canal/none

021973269 Vogtle Thermoelectric/ Savannah River/ 1987 2,320,000 Georgia Power Company nuclear none

02198745 McIntosh Thermoelectric/ Savannah River/ 1979 178,000 Savannah Electric and Power Company fossil fuel none

02198930 Port Wentworth Thermoelectric/ Savannah River/ 1958 334,000 Savannah Electric and Power Company fossil fuel none

02198977 Riverside Thermoelectric/ Savannah River/ 1949 80,000 Savannah Electric and Power Company fossil fuel none

ALTAMAHA RIVER BASIN

02207301 Milstead Hydroelectric/ Yellow River/ 1924 800 McRay Energy Inc. run-of-river power pool

02207540 Porterdale Hydroelectric/ Yellow River/ 1927 1,600 Porterdale Associates run-of-river power pool

21 Table 5. Power-generating plants in Georgia—Continued [Modified from Fanning and others, 1991]

Station P la nt n am e Typ e/ Water source/ Year Capacity number Owner Fuel source Reservoir in service (kilowatts)

02210000 Lloyd Shoals Hydroelectric/ Ocmulgee River/ 1911 14,400 Georgia Power Company storage Lloyd Shoals Reservoir

ALTAMAHA RIVER BASIN—Continued

02212510 Scherer Thermoelectric/ Ocmulgee River and Rum Creek 1982 3,270,000 Georgia Power Company fossil fuel Lake Juliette

02212890 Arkwright Thermoelectric/ Ocmulgee River/ 1941 160,000 Georgia Power Company fossil fuel none

02218130 Barnett Shoals Hydroelectric/ Oconee River/ 1910 2,800 Georgia Power Company run-of-river power pool

02220450 Wallace Hydroelectric/ Oconee River/ 1980 321,000 Georgia Power Company storage Lake Oconee

02222247 Harlee Branch Thermoelectric/ Oconee River/ 1965 1,540,000 Georgia Power Company fossil fuel Sinclair Reservoir

02222500 Sinclair Hydroelectric/ Oconee River/ 1953 45,000 Georgia Power Company storage Sinclair Reservoir

02225001 Edwin I. Hatch Thermoelectric/ Altamaha River/ 1975 1,163,000 Georgia Power Company nuclear none

SATILLA–ST MARYS RIVER BASINS

022261765 McManus Thermoelectric/ Turtle Creek/ 1952 115,000 Georgia Power Company fossil fuel none

CHATTAHOOCHEE RIVER BASIN

02334400 Buford Hydroelectric/ Chattahoochee River/ 1957 86,000 U.S. Army Corps of Engineers storage Lake Sidney Lanier

02335810 Morgan Falls Hydroelectric/ Chattahoochee River/ 1904 16,800 Georgia Power Company storage Blue Sluice Lake

02336479 Atkinson Thermoelectric/ Chattahoochee River/ 1930 240,000 Georgia Power Company fossil fuel none

02336480 McDonough Thermoelectric/ Chattahoochee River/ 1963 490,000 Georgia Power Company fossil fuel none

02338030 Yates Thermoelectric/ Chattahoochee River/ 1950 1,250,000 Georgia Power Company fossil fuel none

02338330 Wansley Thermoelectric/ Chattahoochee River and Yellow 1976 1,730,000 Georgia Power Company fossil fuel Dirt Creek/none

02339400 West Point Hydroelectric/ Chattahoochee River/ 1975 73,400 U.S. Army Corps of Engineers storage West Point Lake

02339780 Langdale Hydroelectric/ Chattahoochee River/ 1924 1,040 Georgia Power Company run-of-river power pool

02339820 Riverview Hydroelectric/ Chattahoochee River/ 1918 480 Georgia Power Company run-of-river power pool

02341000 Bartletts Ferry Hydroelectric/ Chattahoochee River/ 1926 173,000 Georgia Power Company storage Lake Harding

02341300 Goat Rock Hydroelectric/ Chattahoochee River/ 1912 26,000 Georgia Power Company run-of-river power pool

02341400 Oliver Hydroelectric/ Chattahoochee River/ 1959 60,000 Georgia Power Company storage Lake Oliver

22 Table 5. Power-generating plants in Georgia—Continued [Modified from Fanning and others, 1991]

Station P la nt n am e Typ e/ Water source/ Year Capacity number Owner Fuel source Reservoir in service (kilowatts)

CHATTAHOOCHEE RIVER BASIN—Continued

02341420 North Highlands Hydroelectric/ Chattahoochee River/ 1963 29,600 Georgia Power Company run-of-river power pool

02341480 Eagle and Phenix #1 and #2 Fieldcrest Hydroelectric/ Chattahoochee River/ 1915 31,800 Cannon Inc. run-of-river power pool

02343240 Walter F. George Hydroelectric/ Chattahoochee River/ 1963 130,000 U.S. Army Corps of Engineers storage Walter F. George Lake

02343830 Joseph M. Farley Thermoelectric/ Chattahoochee River/ 1977 1,720,000 Alabama Power Company nuclear none

FLINT RIVER BASIN

02350390 Crisp Thermoelectric/ Flint River/ 1958 12,500 Crisp County Power Commission fossil fuel Lake Blackshear

02350400 Warwick Hydroelectric/ Flint River/ 1930 16,400 Crisp County Power Commission storage Lake Blackshear

02350550 Flint River Hydroelectric/ Flint River/ 1921 5,400 Georgia Power Company storage Lake Worth

02352790 Mitchell Thermoelectric/ Flint River/ 1948 170,000 Georgia Power Company fossil fuel none

02357500 Jim Woodruff Hydroelectric/ Apalachicola River/ 1957 49,800 U.S. Army Corps of Engineers storage Lake Seminole

COOSA RIVER BASIN

02381400 Carters Hydroelectric/ Coosawattee River/ 1976 500,000 U.S. Army Corps of Engineers storage Carters Lake

02393500 Allatoona Hydroelectric/ Etowah River/ 1950 74,000 U.S. Army Corps of Engineers storage Allatoona Reservoir

02394140 Cartersville Hydroelectric/ Etowah River/ 1927 625 ECC American International run-of-river power pool

02394775 Bowen Thermoelectric/ Etowah River/ 1971 3,160,000 Georgia Power Company fossil fuel none

02397800 Hammond Thermoelectric/ Coosa River/ 1954 800,000 Georgia Power Company fossil fuel none

TENNESSEE RIVER BASIN

034999268 Estatoah Hydroelectric/ Mud Creek/ 1928 240 Georgia Power Company run-of-river power pool

03553000 Nottely Hydroelectric/ Nottely River/ 1956 15,000 Tennessee Valley Authority storage Nottely Lake

03558500 Blue Ridge Hydroelectric/ Toccoa River/ 1931 20,000 Tennessee Valley Authority storage Blue Ridge Lake

23 ° 35° 85 84° EXPLANATION

Major river basin boundary Dalton Physiographic province boundary Towns greater than 10,000 83° population (1980 Census) Rome Gainesville Cartersville Roswell/ Sandy Springs 34° Marietta Athens Smyrna Atlanta

Carrollton

Forest Park Covington 82° Newnan Augusta Griffin

La Grange Milledgeville 33° Line

Macon Fall Warner Dublin Robins Columbus Statesboro

Vidalia Americus 81° Savannah 32° Cordele Hinesville

Fitzgerald Douglas Albany Tifton

Waycross Brunswick Moultrie

31° Bainbridge Thomasville Valdosta

Base from U.S. Geological Survey digital files

0 10 20 30 40 50 60 70 MILES

0 10 20 30 40 50 60 70 KILOMETERS

Figure 13. Locations of cities in Georgia having populations greater than 10,000 (data from U.S. Department of Commerce, U.S. Bureau of Census, 1982).

24 typical of stations below small dams or systems of small South of the Ogeechee River basin, near the dams. For each station, the data tend to show higher Georgia coast and downstream of several small inland stream temperatures, particularly in the warmer months, streams, lies the Newport River tidal estuaries. Long- than would be expected from the statewide harmonic term observed stream-temperature characteristics for equation (figs. 20–28). This primarily is caused by the Peacock Creek at McIntosh (station 02203559) are discharge of warm water from the surface of small shown in figure 45. This station and six other nearby impoundments. Similar effects on long-term stream- tidal stations—(02203566, 02203570, 02203574, temperature characteristics may result from farm ponds 02203578, 02203585, and 02203596), not shown in or small recreational lakes. The magnitude of the effects illustrations of this report—have substantially warmer will depend primarily on storage, stream discharge, stream temperatures year round than temperatures nature of the system of impoundments, thermal computed from the statewide harmonic equation. stratification, location of impoundment discharge, and Observed harmonic-mean temperatures range from the distance of the site below the dam about 1.6 ° C warmer than computed data at Peacock or dams. Creek at McIntosh (station 02203559) to about 2.5 ° C warmer seaward at North Newport River at Halfmoon Ogeechee River Basin Landing (station 02203578). In the tidal reaches of nearby estuaries, stream-temperature characteristics, as The Ogeechee River basin has a drainage area of depicted by the observed data, show an amplitude about about 4,690 mi2 and lies mostly within the Coastal Plain 1.1 to 1.9 ° C higher than values generated by the Province, with relatively small headwaters in the statewide harmonic equation. The statewide harmonic Piedmont Province (fig. 1). The Ogeechee River basin equation was derived from inland stream-temperature lies south of the Savannah River basin and does not data and should not be used to estimate temperature contain either large reservoirs or urban areas. characteristics of tidal waters. The first station for which stream-temperature characteristics are illustrated is the Ogeechee River at Altamaha River Basin Scarboro (station 02202000). This station is about mid- Rapidly developing basins, such as those around basin without nearby stations to compare observed the Atlanta Metropolitan area, are likely to have long- stream-temperature data. Figure 40 shows term stream-temperature characteristics that vary from that observed stream temperatures of Ogeechee River those estimated by the statewide harmonic equation. at Scarboro plot about 1 to 2 ° C lower than those Within such a basin, the data user may need to consider estimated by the statewide harmonic equation. effects of basin modifications to better estimate current, Annual long-term stream-temperature or future, stream-temperature characteristics. characteristics for Ogeechee River at Oliver (station The Altamaha River originates in the Piedmont 02202190) are shown in figure 41. Harmonic stream- Province of northern Georgia (fig. 1). The Oconee and temperature characteristics generated from observed Ocmulgee Rivers account for about 5,250 and 6,080 data agree with values from the statewide harmonic mi2, respectively, of the Altamaha River’s total 14,480 equation, except for the period October through March, mi2 drainage area. The Ocmulgee River headwaters where values are about 0.5 to 1.0 ° C lower. include the Atlanta Metropolitan area and less densely Stream-temperature characteristics for the next populated areas to the east. Stream-temperature- downstream mainstem station, Ogeechee River near characteristic curves for the upper Ocmulgee River Eden (station 02202500), are shown in figure 42. basin, including the South River basin, are shown in Stream-temperature characteristics generated by the figures 46 through 51. Stream temperatures of the upper observed data agree with values from the statewide reaches of the South River are higher than predicted by harmonic equation. the statewide harmonic equation, probably because of discharge from nearby Atlanta and DeKalb County, Ga., The Canoochee River is a major tributary to the waste-water treatment facilities and other municipal and 2 Ogeechee River and drains about 1,400 mi . Natural industrial basin modifications that usually accompany stream-temperature characteristics computed from the development. The 1985 completion of the city of statewide harmonic equation and characteristics Atlanta's “Three Rivers Project” rerouted waste water computed from observed data for Canoochee River near from the Chattahoochee River basin away from the Claxton (station 02203000) and Canoochee River at upper reaches of the South River, and back into the Fort Stewart (station 02203519 are shown in figures 43 Chattahoochee River. Therefore, stream-temperature and 44). characteristics subsequent to 1985 likely will change.

25 The Yellow and Alcovy River basins, in the eastern Lake Oconee, where storage began in 1979 (fig. 76). part of the upper Ocmulgee River basin are experiencing Sinclair Reservoir is downstream from Lake Oconee. more rapid development as the Atlanta Metropolitan Oconee River at Milledgeville (station 02223000) (fig. area continues to grow. Pre-1985 annual observed 80) depicts annual temperature characteristics about 3.8 temperatures match the statewide harmonic equation river miles downstream of Sinclair Dam. The effects of values well for the Yellow River near Snellville (station the newer Lake Oconee upon the stream-temperature 02206500), Yellow River at Conyers (station characteristics of this station and the downstream 02207300), Yellow River near Covington (station stations, Oconee River near Hardwick (station 02207500), Yellow River at Porterdale (station 02223040) (fig. 81); Oconee River near Toomsboro 02207540), Yellow River near Stewart (station (station 02223250) (fig. 82); Oconee River at Dublin 02208005), and Alcovy River at Newton Factory (station 02223500) (fig. 84); and Oconee River near Bridge Road near Stewart (station 02209260) (figs. Dublin (station 02223600) (fig. 85) are unknown. 52–57) except during cooler months from about However, the latter two stations in the vicinity of November through February, when plots show about Dublin show little effect because of the distance 1 ° C lower temperatures. downstream and the increased streamflow from the larger drainage area. The confluence of the South and Yellow Rivers form the Ocmulgee River that is joined by the Alcovy Stream-temperature characteristics of the River in the upper part of Lloyd Shoals Reservoir mainstem Altamaha River are regarded mostly as (Jackson Lake). The stream-temperature characteristics natural. The records for the Altamaha River stations at of the Ocmulgee River near Jackson (station 02210500), Baxley (station 02225000) (fig. 87), Jesup (station about 1 mile downstream from Lake Jackson, are shown 02225990) (fig. 90), Doctortown (station 02226000) in figure 58. Annual harmonic characteristics are shown (fig. 91), Gardi (station 02226010) (fig. 92), and Everett for the Towaliga River near Jackson (station 02211300) City (station 02226160) (fig. 94) show that temperatures (fig. 59), where stream temperatures are about 3 ° C for June through September have maximums in the 29 to lower than estimates from the statewide harmonic 32 ° C range. Seasonal natural maximum temperatures equation throughout the winter months. Downstream, in these temperature ranges are corroborated by the the Ocmulgee River in the vicinity of Macon (stations statewide harmonic equation. 02212950 and 02213000) (figs. 61 and 62) reflects the usual municipal and industrial modifications associated Satilla River–St Marys River Basins with a developed area. Upstream fossil-fuel plants likely also contribute to the modified temperature The Satilla and St Marys River basins (fig. 1) lie in characteristics of these two Ocmulgee River stations. the Coastal Plain Province and drain about 4,380 mi2 in Observed data for the Ocmulgee River at Lumber City southern Georgia and about 1,150 mi2 in northeastern (02215500) (fig. 71) agrees with the estimated long- Florida. The Satilla River basin covers most of the area, term natural stream-temperature characteristics derived encompassing about 3,530 mi2. Both basins have very by the statewide harmonic equation. low relief, with headwater altitudes for the Satilla River at about 350 feet and St Marys River at about 120 feet. Stream-temperature characteristics for four The Satilla River basin, like the nearby Altamaha River stations in the upper Oconee River basin—Allen Creek basin, is characterized by high summer temperatures at Talmo (station 02217000); Middle Oconee River near having observed maximum temperatures in the 29 ° to Athens (station 02217500); North Oconee River at 34 ° C range. Athens (station 02217740); and Oconee River at Barnett Shoals near Watkinsville (station 02218000)—are Long-term stream-temperature characteristics of shown in figures 72, 73, 74, and 75, respectively. six stations in the Satilla River basin are shown in Observed data from all of these stations agree figures 95-100. Two of the six stations, Satilla River reasonably well with long-term natural stream- near Waycross (station 02226500) (fig. 96) and Satilla temperature characteristics estimated by the statewide River at Atkinson (station 02228000) (fig. 100), show harmonic equation. deviation of observed data from the statewide harmonic equation. The estimated natural harmonic-mean Stream-temperature data shown for Oconee River temperatures for both stations are about 0.9 ° C lower near Greensboro (station 02218500) primarily have than the harmonic mean indicated by observed data. historic utility because the stream reach now lies within

26 Suwannee-Ochlockonee River Basins period plotted below the statewide harmonic equation in both instances. Principal streams in the Suwannee River and Ochlockonee River basins in Georgia are the Chattahoochee River Basin Withlacoochee, Alapaha, Suwannee and Ochlockonee Rivers (fig. 1). The Suwannee and Ochlockonee River The Chattahoochee River basin extends from the basins cover south-central Georgia and north-central Blue Ridge Province in northern Georgia to the Florida and are about equally divided between the two southwestern tip of the State at the confluence with the 2 States. The Okefenokee Swamp is in the headwaters of Flint River (fig. 1). The basin drains about 8,770 mi , the Suwannee River and covers about 1,100 mi2 of the mostly in Georgia. The maximum width of the basin is eastern end of the basin at an altitude of about 120 feet. about 55 miles. The Suwannee River flows southward and then The Chattahoochee River system is the principal westward into the Gulf of Mexico. The headwaters of water supply for about one half of Georgia’s population both the Withlacoochee and Alapaha Rivers are in the (Marella and others, 1993). In addition, the river system northern end of the basin with altitudes at about 450 ft. serves industry; provides recreation and fishing; Long-term harmonic characteristics are shown generates power; assimilates wastes; and in the southern for 12 stations in the Suwannee River basin (figs. 101– reaches of the river, supports shipping. Population 112). The harmonic-mean stream temperature projections for the upper Chattahoochee River basin, computed from observed data for Suwannee River at within the Piedmont Province, predict continuing Fargo (station 02314500) (fig. 101) is about 0.6 ° C growth (Brown, 1981). higher than the value computed from the statewide Long-term observed stream-temperature harmonic equation. This station includes the drainage characteristics for stations within the Chattahoochee of much of the Okefenokee Swamp which may account River basin are shown in figures 117–145. Figures 117 for the slightly higher stream-temperature through 119 show temperature-characteristic curves for characteristics. As in the adjacent Satilla River basin, three stations—Chattahoochee River near Leaf summer temperatures are high, with observed (station 02331000); Chattahoochee River near Cornelia temperatures as high as 31 ° C, and winter (station 02331600); and Chestatee River at State temperatures vary widely from 4 to 21 ° C. Highway 52 near Dahlonega (station 02333500)—in Four Ochlockonee River basin stations— the upper part of the basin. Each of these three stations Ochlockonee River near Moultrie (station 02327205); compare well with curves computed from the statewide Ochlockonee River near Thomasville (station harmonic equation and shows mostly natural stream- 02327500); Tired Creek near Cairo (station 02328000); temperature characteristics. and Ochlockonee River near Calvary (station Stream-temperature characteristics for 02328200)—are shown in figures 113–116. The Chattahoochee River near Buford (station 02334500), harmonic stream-temperature coefficients computed about 2.3 miles downstream from Lake Sidney Lanier from observed data closely match those from the are shown in figure 120. A harmonic-mean observed statewide harmonic equation except for Ochlockonee stream temperature of about 9.2 ° C is 6.1 ° C lower River near Calvary (station 02328200) (fig. 116), which than the mean estimated by the statewide harmonic plots about 1.4 ° C lower than the curve formed by the equation. In this reach of the Chattahoochee River, statewide equation. However, the Ochlockonee River observed year-round temperatures are about the same as near Calvary station data spans only the 1974–84 minimum winter temperatures estimated by the period. Values computed from the statewide harmonic statewide harmonic equation. These lower temperatures equation agree well with those values computed from occur because of the dominant impact of storage of large observations for Ochlockonee River near Thomasville volumes of winter-season water in the large reservoir, (station 02327500) (fig. 114) with data spanning the Lake Sidney Lanier near Gainesville, Ga., formed by years 1954–84. A reexamination of harmonic Buford Dam. Water from Lake Sidney Lanier is coefficients for the Ochlockonee River near discharged from depth, unlike surface-outlet structures Thomasville station for the 1974–84 period (as was used characteristic of smaller ponds mentioned earlier. A for the Ochlockonee River near Calvary station) phase coefficient lag of 0.64 radians effectively shifts indicates that the harmonic mean for the Thomasville the stream-temperature season by about 37 days. Cooler station also was about 0.9 ° C below the values than natural stream temperatures also were observed at computed by the statewide harmonic equation. Chattahoochee River near Norcross (station 02335000) Therefore, observed temperature data for the 1974–84 (fig. 121), about 18 miles downstream from Lake Sidney

27 Lanier. Thirty-five stream-temperature measurements statewide harmonic equation. Stream-temperature during May 1937 to December 1938 for the characteristics from observed data for North Fork Camp Chattahoochee River at Atlanta (station 02336000) prior Creek at Atlanta (02337100) (fig. 128) show substantial to the construction of Lake Sidney Lanier are shown in departure from values calculated by the statewide figure 123. Long-term stream-temperature harmonic equation. However, the drainage area of characteristic curves for Chattahoochee River at Atlanta North Fork Camp Creek at Atlanta is only 5.3 mi2; well (station 02336000) for the period after Lake Sidney below the 20 mi2 minimum drainage area recommended Lanier (1957-79) are shown in figure 124. At for use with the statewide harmonic equation. Chattahoochee River at Atlanta, summer temperatures Stream-temperature characteristics for average about 6.0 ° C lower than computed natural Chattahoochee River mainstem stations, Chattahoochee values. The station is located about 9.5 river miles River near Fairburn (station 02337170), Chattahoochee downstream from Morgan Falls Dam, a small 16.8 near Whitesburg (station 02338000), and kilowatt power-generation and river-regulation facility. Chattahoochee River at U.S. Highway 27 at Franklin Harmonic stream-temperature characteristic (station 02338500) are shown in figures 129, 132, and curves for Peachtree Creek at Atlanta (station 133, respectively. Stream-temperature characteristics 02336300), are shown in figure 125. The Peachtree for Chattahoochee River at West Point (station Creek basin is totally within the Atlanta Metropolitan 02339500) are shown in figures 136 and 137. The area. Stream-temperature measurements at this station is about 3 miles downstream from West Point station show summer maximum temperatures in the Lake. Figure 136 depicts pre-West Point Lake 28 to 31 ° C range. The harmonic maximum for the conditions and figure 137 represents post-West Point observed temperature data is about 26 ° C—about 3 ° C Lake conditions. Stream-temperature characteristics higher than statewide harmonic equation values. show only a slight damping of post-Lake harmonic Harmonic maximum stream temperatures of this natural amplitude from 9.2 to about 9.1 ° C. The most magnitude would normally be expected to apparent post-Lake difference is in the phase coefficient occur much farther south, indicating the effects of which changed from about 2.8 to about 2.6 radians or a urban development. seasonal lag of about 12 days.

Stream-temperature characteristics at Flint River Basin Chattahoochee River at Interstate Highway 285 near Atlanta (station 02336502) are shown in figure 126. The headwaters of the Flint River are located in the Piedmont Province of Georgia in the highly developed Temperatures show a marked increase over values from area south of Atlanta (fig. 1). The basin has Chattahoochee River at Atlanta (station 02336000) 2 which is about 5.3 river miles upstream. The harmonic- a drainage area of about 8,460 mi and an average width of about 40 miles. mean temperature increase of about 2.6 ° C is caused, in part, by the return of cooling water from electric- Long-term annual harmonic stream-temperature generating plants and from wastewater returns. Summer characteristics for stations in the Flint River basin are temperatures show more variability than natural, with shown in figures 146–167. Harmonic mean and some measured values near 30.0 ° C, which is more amplitude coefficients from the upper reaches of the typical of a south Georgia stream. Also, as mentioned basin typically are about 1 to 2 ° C above values earlier, differing analysis periods (1957–79 for computed from the statewide harmonic equation. Chattahoochee River at Atlanta) also could account for This may be attributable to natural causes and effects of some of the differences between the two stations. development near the stations. Long-term stream- temperature characteristics for Flint River near Culloden Long-term stream temperatures for four tributary (station 02347500) are shown in figure 154. At this streams—Sweetwater Creek near Austell (station station, the computed harmonic mean coefficient is 02337000); North Fork Camp Creek at Atlanta about 0.2 ° C higher and the amplitude coefficient is (station 02337100); Dog River near Fairplay (station about 0.8 ° C higher than values computed from the 02337438); and Snake Creek near Whitesburg (station statewide harmonic equation. Flint River near Culloden 02337500)—are shown in figures 127, 128, 130, and was among stations selected as mostly natural and it was 131. Amplitude coefficients determined by observed used to compute the statewide harmonic equation. data for Sweetwater Creek near Austell (02337000) (fig. 127) and Dog River near Fairplay (02337438) (fig. 130) are about 0.8 ° C above values predicted by the

28 Downstream, Whitewater Creek below Coosawattee River at Carters (station 02382500) (fig. Rambulette Creek near Butler (station 02349000) 172) and 1957-72 for Coosawattee River near Pine (fig. 155) was selected as a natural stream-temperature Chapel (station 02383500) (fig. 174) are prior to the characteristics site. However, characteristics for this impoundment of Carters Lake; and therefore, primarily station generated by the statewide harmonic equation have historic utility. Modified stream-temperature differ substantially from values shown by the more characteristics for Coosawattee River near Calhoun damped actual-data curve. This damping primarily is (station 02383540) for the post-Carters Lake period of due to the large ground-water discharge to streams 1974-84 are shown in figure 175. Carters Lake and its within the Whitewater Creek basin. For example, re-regulation dam cause a shift in the natural phase co- during extended low-flow periods, streamflows of efficient that amounts to a seasonal lag of about 15 days. Whitewater Creek below Rambulette Creek near Butler Also, the observed-data amplitude value of 8.8 ° C is (drainage area of 94 mi2) approach streamflows of the lower than the estimated natural value of about 9.6 ° C. much larger drainage area of the Flint River near Stream-temperature characteristics for two small Culloden (1,850 mi2). The data-derived harmonic-mean Coosa River basin tributary streams—Scarecorn Creek coefficient of 17.1 ° C is greater than the regionally at Hinton (station 02382000) and Rock Creek near computed harmonic mean of 16.6 ° C. A similar affect, Fairmont (station 02383000)—are shown in figures 171 but not as pronounced, of ground-water discharge to and 173, respectively. The harmonic-characteristic streams also is seen in figure 157 for Turkey Creek at curves for both stations average 1.0 to 1.5 ° C above the Byromville (station 02349900). statewide harmonic equation. Long-term annual harmonic stream-temperature Annual temperature-characteristic curves for characteristics for the lower Flint River basin tributary Conasauga River near Dalton (station 02384748) and stations are shown in figures 159, 163, 164, and 167. Holly Creek near Chatsworth (station 02385800) are Data-derived harmonic curves agree well with the shown in figures 176 and 177. Both stations are statewide harmonic equation curves, except for Pachitla considered representative of mostly natural Creek near Edison (station 02353400) (fig. 163) and conditions and are included in the stations used for the Ichawaynochaway Creek at Milford (station 02353500) statewide regression analyses (table 3). The harmonic (fig. 164), where amplitude coefficients are damped by mean and amplitude coefficients are about 0.5 ° C about 0.9 ° C, possibly because of ground-water inflow. higher than values computed from the statewide Figures 162, 165, and 166 show annual harmonic harmonic equation. characteristics of three lower mainstem Flint River Annual stream-temperature characteristic curves stations: Flint River at Newton (station 02353000), Flint for Conasauga River at Tilton (station 02387000) and River at Bainbridge (station 02356000), and Flint River Conasauga River near Resaca (station 02387050) are below State Docks at Bainbridge (station 02336015). shown in figures 178 and 179. Temperatures recorded at The temperature characteristics of the latter two of these the Tilton station likely are affected by industrial and stations may be somewhat affected by backwaters of land-use activities in the Dalton area. Natural Lake Seminole. temperatures for stations having similar basin Coosa River Basin characteristics as the Tilton station typically occur further south. Downstream, at Conasauga River near 2 The Coosa River basin covers about 4,360 mi of Resaca (station 02387050) (fig. 179), harmonic-mean Valley and Ridge, Blue Ridge, and Piedmont Provinces and amplitude coefficients from observed data are about in northwest Georgia (including a small part of southern 0.6 and 0.8 ° C higher than respective values generated Tennessee) (fig. 1). The Coosa River is formed by the by the statewide harmonic equation. confluence of the Oostanaula and Etowah Rivers (fig. 2). Streams in this basin serve many small towns; In the vicinity of Resaca, Ga., the Conasauga and several hydropower and steam-power facilities; large Coosawattee Rivers combine to form the Oostanaula industrial centers, such as the carpet industry at Dalton; River. The first Oostanaula River temperature station and several medium-size towns, such as Rome. downstream of this confluence is the Oostanaula River at Resaca (station 02387500). The data and Long-term annual stream-temperature characteristic curves for this station are shown in figure characteristics of headwater streams are shown in 180. The period of observed temperature data analysis figures 168–170. For these stations, the statewide (1957-72) preceded the construction of Carters Lake and harmonic equation yields amplitudes from about 0.3 to was included as one of the 78 statewide harmonic 0.9 ° C greater than those derived from data. Further analysis stations (table 3). downstream, the records for the period 1965–72 for 29 Harmonic curves for Oostanaula River at I-75 at amplitude from the statewide harmonic equation. Resaca (station 02387502) for the post-Carters Lake Figures 188 and 189 show the temperature period of 1974–84 are shown in figure 181. This station characteristics at Little River near Roswell (station is only a few miles downstream from the confluence of 02392500) for periods 1959–64 and 1964–75, the Conasauga and Coosawattee Rivers. Stream respectively. The harmonic mean and amplitude temperatures at Oostanaula River at I-75 at Resaca more coefficients computed from the 1964–75 data are about closely resemble the post-Carters Lake temperatures of 1.5 ° C above respective values from 1959–64 and from the higher yielding Coosawattee River near Calhoun the statewide harmonic equation. These differences (fig. 175), with damped harmonic mean and amplitude, likely are due to urban development, stream than those of the Conasauga River near Resaca channelization, and pond construction within the Little (fig. 179). River basin. Harmonic temperature curves computed from Computed annual stream-temperature observed data and the statewide harmonic equation for characteristics for Etowah River at Allatoona Dam West Armuchee Creek near Subligna (station 02388000) above Cartersville (station 02394000) for a short pre- are shown in figure 182. West Armuchee Creek near Allatoona Reservoir period are shown in figure 190. Subligna has a small 36 mi2 drainage area. During Allatoona Reservoir was completed in 1949 and is winter months, the observed-data curve is several located about 0.8 miles upstream from station degrees higher than the statewide harmonic equation 02394000. Because the pre-Allatoona Reservoir record, curve. This difference likely is attributable to shown in figure 190, continued only about one year substantial ground-water discharge, characteristic of (1938–39), no harmonic curve is shown for the data. many small streams within the Valley and Annual stream-temperature characteristics for the post- Ridge Province. Allatoona Reservoir period (1958-84) are shown in figure 191. The more current record shows harmonic Figure 183 shows pre-Carters Lake data (1957–73) mean and amplitude coefficients both about 0.4 ° C for Oostanaula River at Rome (station 02388500). lower and the phase coefficient about 0.42 radians lower Harmonic curves from the statewide harmonic equation than respective values of the statewide harmonic and from the observed data are in close agreement with equation. The shift in phase coefficient amounts to a harmonic mean, amplitude, and phase coefficients, seasonal lag of about 24 days. differing only by 0.3 ° C, 0.4 ° C, and 0.07 radians, respectively. The harmonic curve from the post-Carters Harmonic characteristics for Etowah River above Lake period is shown for Oostanaula River (Rome Kingston (station 02394980), Etowah River near Intake) at Rome (station 02388520) in figure 184. Kingston (station 02395000), and Etowah River at The only harmonic coefficient that shows a noticeable Rome (station 02396000) are shown in figures 193, 194, difference from the statewide harmonic equation for and 195. Harmonic characteristics computed from the period 1974-84 is the phase coefficient, with a lag measurements for these reaches of the Etowah River of about 0.13 radians or about eight days. reflect the effects of reservoir, industrial, municipal, and fossil-fuel power-generation activities. Annual harmonic stream-temperature characteristics for Etowah River near Dawsonville The Coosa River is formed by the confluence of (station 02389000) are shown in figure 185. The the Oostanaula and Etowah Rivers in Rome, Ga. Figure harmonic curve from the statewide harmonic equation 196 shows stream-temperature characteristics for Coosa plots about 1 ° C above the curve derived from River near Rome (station 02397000) for the period observed data for January through July. This is 1957-84. Harmonic coefficients computed from the consistent with Etowah River near Canton (station periodic stream-temperature measurements show about 02392000) shown in figure 187. For the Canton a 0.6 ° C compression and a 0.16 radian (about 10 days) station, the 1 ° C cooler temperature is evident year lag for the amplitude and phase coefficients, round. Both the Dawsonville and Canton stations are respectively, when compared with coefficients from the among those selected to compute the statewide statewide harmonic equation. Allatoona Dam on the harmonic equation. Figure 186 shows stream- Etowah River may be the principal cause of most of temperature data and characteristics for Shoal Creek these differences. near Dawsonville (station 02389300). The observed Harmonic coefficients for tributary Cedar Creek data for the Shoal Creek station shows a harmonic near Cedartown (station 02397500), Chattooga River at amplitude coefficient about 0.8 ° C lower than the Summerville (station 02398000), and Chattooga River

30 at Chattoogaville (02398037) are shown in figures 197, SELECTED REFERENCES 199, and 200, respectively. The Cedartown, Aagaard, F.C., 1969, Temperature of surface waters in Summerville, and Chattoogaville stations all show Montana, prepared for Montana Fish and Game higher harmonic mean and lower amplitude coefficients Department: U.S. Geological Survey (unnumbered than values estimated from the statewide harmonic report), 613 p. equation. This may be caused by larger ground-water Anderson, W.P., 1971, Temperature of Florida streams: discharge to these streams. Florida Department of Natural Resources, Bureau of Annual harmonic stream-temperature Geology, map series 43, 1 plate. characteristics for Coosa River (at the Georgia–Alabama Anderson, P.W., and Faust, S.D., 1973, Characteristics State line) near Coosa (station 02397530) for the period of water quality and stream flow—Passaic River 1974-84 are shown in figure 198. The harmonic curve, basin above Little Falls, New Jersey: U.S. generated by the measured data, plots about 2 to 3 ° C Geological Survey Water-Supply Paper 2026, 80 p. higher than the curve derived from the statewide harmonic equation throughout most of the year. Blakely, J.F., 1966, Temperature of surface waters in the Observed summer stream-temperature maximum and conterminous United States: U.S. Geological Survey average values (harmonic mean values) at Coosa River Hydrologic Investigations Atlas HA-235, near Coosa are typical of streams much farther south. 8 p., 3 plates. Elevated stream temperatures may be attributable to Blodgett, J.C., 1970, Water temperatures of California return flow from power generation at Plant Hammond streams, Sacramento basin subregion: U.S. and other industrial and municipal activities in the Geological Survey Open-File Report (unnumbered). vicinity of Rome, Ga. Brown, C.C., 1981, Metropolitan Atlanta area water- Tennessee River Basin resources management study: Savannah, Ga., U.S. The Tennessee River basin (fig. 1) covers only a Army Corps of Engineers, Environmental Impact few square miles in northern Georgia. In general, the Statement, final report, appendix A-G, variously Tennessee River basin streams in Georgia flow paged. northward to Tennessee; whereas, most other streams in Calandro, A.J., 1969, Temperature analysis of a stream: the State flow southward. Harmonic coefficients U.S. Geological Survey Professional Paper 650-B, p. computed from periodic stream-temperature B174-B179. measurements from the Tennessee River basin (fig. 1) Collings, M.R., 1969, Temperature analysis of a stream: are shown in figures 204-211. Tennessee River basin U.S. Geological Survey Professional Paper 650-B, p. stations used to compute the statewide harmonic B174–B179. equation include Hiawassee River at Presley (station 03545000) (fig. 204); Toccoa River near Dial (station Collings, M.R. and Higgins, G.T., 1973, Stream 03558000) (fig. 207); Fightingtown Creek at temperatures in Washington State: U.S. Geological McCaysville (station 0356000) (fig. 209); South Survey Hydrologic Investigations Atlas HA-385, Chickamauga Creek at Graysville (station 03566800) 4 sheets. (fig. 210); and West Chickamauga Creek near Lakeview Dyar, T.R. and Stokes, W.R., III, 1973, Water (station 03567340) (fig. 211). Each of these curves temperatures of Georgia streams: Atlanta, Ga., except Toccoa River near Dial have harmonic mean Georgia Department of Natural Resources, temperatures about 0.1 to 1.0 ° C higher and amplitudes Environmental Protection Division, unnumbered about 0.1 to 1.1 ° C lower than those computed by the report, 317 p. statewide harmonic equation. Fanning, J.L., Doonan, G.A., Trent, V.P., and Nottely River at Nottely Dam near Ivylog (station McFarlane, R.D., 1991, Power generation and 03553500) (fig. 206) and Toccoa River near Blue Ridge related water use in Georgia: Georgia Geologic (03559000) (fig. 208) are immediately downstream Survey Information Circular 87, 37 p. from impoundments and stream-temperature data indicate modified characteristics. Both stations have Gilroy, E.D., and Steele, T.D., 1972, An analysis of annual harmonic mean and amplitude coefficients about sampling frequency alternatives for fitting a daily 1 ° C lower than values computed from the statewide stream-temperature model in Proceedings, Inter- harmonic equation. Phase coefficients for both stations national Symposium on Uncertainties in Hydrologic are about 2.1 radians, lagging the natural season by and Water Resource Systems, Tucson, Arizona, about 41 days. December 1972: Proceedings, v. 2, p. 594–608. 31 REFERENCES—Continued Steele. T.D., 1974, Harmonic analysis of stream temperatures: Springfield, Va., U.S. Dept. Hawkinson, R.D., Ficke, J.F., and Saindon, L.G., 1977, Commerce, National Technical Information Service, Quality of rivers of the United States, 1974 water Computer Contribution, 47 p. year, based on the National Stream Quality Accounting Network (NASQAN): U.S. Geological Steele, T.D., and Gilroy, E.J., 1972, Harmonic analysis Survey Open-File Report 77-151, 158 p. of stream-temperature data [abs.]: EOS, Transactions of American Geophysical Union, Kothandaraman, V., 1971, Analysis of water- v. 53, no. 4, p. 378. temperature variations in large rivers: American Society Civil Engineers, Journal Sanitary Steele, T.D., Gilroy, E.J., and Hawkinson, R.O., 1974, Engineering Division, v. 97, no. SA1, February An assessment of areal and temporal variations in 1971, p. 19–31. streamflow quality using selected data from the National Stream Quality Accounting Network: U.S. Kothandaraman, V., and Evans, R.L., 1972, Use of air- Geological Survey Open-File Report 74-217, 210 p. water relationships for predicting water temperature: Urbana, Ill., Illinois State Water Survey, Report of Stokes, W.R., III, and McFarlane, R.D., 1995, Water- Investigation 69, 14 p. resources data, Georgia, water year 1994: U.S. Geological Survey Data Report GA-94-1, 643 p. Lamar, W.L., 1944, Chemical character of surface waters of Georgia: U.S. Geological Survey Water- Tasker, G.D., and Burns, A.W., 1974, Mathematical Supply Paper 889-E, p. 325–334. generalization stream temperatures in central New England: American Water Resources Association, Marella, R.L., Fanning, J.L., and Mooty, W.S., 1993, Water Resources Bulletin, p. 1,133–1,142. Estimated use of water in the Apalachicola- Chattahoochee-Flint River basin during 1990 with Thomann, R.V., 1967, Time-series analysis of water- State summaries from 1970 to 1990: U.S. quality data: American Society of Civil Engineers, Geological Survey Water-Resources Investigations Journal of the Sanitary Engineering Division., Report 93-4084, 45 p. v. 93, no. SA1, February 1967, p. 1–23. McCarthy, L.T., Jr., and Keighton, W.B., 1964, Quality U.S. Department of Commerce, U.S. Bureau of Census, of Delaware River water at Trenton, New Jersey in 1982, Census of population and housing, block Contributions to the hydrology of the United States: statistics, 1980: Washington, D.C., U.S. Bureau of U.S. Geological Survey Water-Supply Paper 1779, Census, Report PHC801-1,498 p. p. X-1—X-51, 1 plate. Ward, J.C., 1963, Annual variation of stream-water Moore, A.M., 1967, Correlation analysis of water temperature: American Society of Civil Engineers, temperature data for Oregon streams: U.S. Journal of the Sanitary Engineering Division, v. 89, Geological Survey Water-Supply Paper 1819-K, no. SA6, p. 1–16. 53 p. Williams, O.O., 1971, Analysis of stream temperature Pluhowski, E.J., 1970, Urbanization and its effect on the variations in the upper Delaware River Basin, New temperature of streams on Long Island, New York: York: U.S. Geological Survey Water-Supply U.S. Geological Survey Professional Paper 627-D, Paper 1999-K, 45 p. 110 p. Woodard, T.H., 1970, Summary of data on temperature Rawson, Jack, 1970, Reconnaissance of water of streams in North Carolina, 1943-67: U.S. temperature of selected streams in southeastern Geological Survey Water-Supply Paper 1895-A, Texas, prepared by U.S. Geological Survey for 39 p. Texas Water Development Board: Austin, Tx., Texas Water Development Board, Report 105, 12 p. Reheis, H.F., Dozier, J.C., Word, D.M. and Holland, J.R., 1982, Treatment-cost savings through monthly variable effluent limits: Journal of the Water Pollution Federation, v. 54, no. 8, p. 1,224–1,230.

32 TABULAR DATA

33 88.1 84.5 86.1 64.0 89.1 75.3 85.1 89.4 93.3 90.3 93.3 89.4 84.9 99.9 99.7 85.9 90.2 82.2 78.1 82.9 Variance Variance (percent) 2.22 2.00 2.10 2.12 2.26 2.20 1.82 1.93 1.78 2.04 1.97 1.99 1.87 1.88 2.30 2.00 2.43 2.43 2.88 1.98 error (° C) Standard Standard 2.80 2.77 2.69 2.17 2.82 2.56 2.71 2.79 2.66 2.82 2.68 2.79 2.87 2.85 2.78 2.80 2.82 2.79 2.71 2.42 Phase (radians) coefficient coefficient from observed data 9.2 7.2 8.4 5.1 8.9 6.7 9.4 7.9 9.2 9.0 9.7 8.2 9.6 9.5 8.9 6.9 11.3 11.6 10.9 10.5 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 13.6 12.0 13.2 13.3 15.5 16.6 14.7 15.5 14.4 17.0 15.0 16.5 16.0 15.7 15.4 14.3 16.4 15.3 16.9 16.6

29.0 24.0 25.5 24.0 27.0 25.0 27.0 29.5 25.0 31.5 26.0 29.0 29.0 25.5 28.5 25.0 27.0 26.5 26.5 26.0 (° C) Maximum Observed 1.0 2.0 1.0 4.0 3.0 6.0 1.5 3.0 4.0 4.5 1.5 4.5 4.0 4.0 4.5 2.0 1.5 1.0 4.0 6.0 (° C) stream temperature Minimum 75 93 34 53 53 52 50 60 46 51 61 56 83 56 53 260 174 101 100 147 and harmonic properties of Number observations of record record Period analyzed 09/57-12/84 07/64-08/84 09/59-06/74 05/58-11/84 02/58-07/75 09/57-07/74 10/58-08/68 10/58-10/69 10/58-08/68 10/58-07/68 07/58-08/68 07/62-08/68 07/62-08/68 10/62-09/68 10/62-09/70 08/62-07/75 10/56-10/79 10/54-06/74 03/68-07/76 02/58-07/73 97 (ft) 674 432 581 364 894 870 750 743 680 731 735 682 600 695 357 354 271 1,166 1,869 Altitude Altitude ected station information, ected station SAVANNAH RIVER BASIN RIVER SAVANNAH ) 2 57 33 38 19 42 61 3.7 0.7 4.0 3.8 1.2 7.5 207 119 291 10.3 area area (mi 2,231 2,876 1,430 7,508 Drainage Longitude 83°18'22" 83°31'50" 83°20'43" 82°44'42" 82°56'38" 82°38'30" 83°22'00" 83°22'00" 83°19'19" 83°18'38" 83°14'23" 83°14'02" 83°13'23" 83°13'19" 83°11'10" 83°29'17" 82°46'12" 82°44'33" 82°07'45" 81°56'35" Latitude periods of analyses, sel of analyses, periods 34°48'50" 34°53'25" 34°40'40" 34°15'20" 34°10'52" 34°04'15" 34°34'25" 34°34'22" 34°30'49" 34°29'07" 34°27'10" 34°29'01" 34°29'35" 34°27'47" 34°19'25" 34°20'15" 33°58'27" 33°36'46" 33°26'36" 33°22'25" Station name Toccoa, Ga. Toccoa, Ga. Avalon, Chattooga near Clayton, River Ga. Ga. Clayton, near River Tallulah Ga. Toccoa, near Creek Panther near S.C. Iva, River Savannah CreekBeaverdam Rose, at Dewy Ga. near Calhoun River Savannah Falls, S.C. North (SWS BroadFork no. River 1) above Ga. Toccoa, near 2) no. (SWS Creek Denmans Ga. North near BroadFork Toccoa, River Bear Creek (SWS no. 6) near Mize, Ga. North near Ga. BroadFork Lavonia, River Creek (SWS no. 11) near Eastanollee,Toms Ga. (SWS Creek no. 14) Tributary near Toms Creek near Martin, Ga. Toms North near BroadFork Carnesville, River Ga. Ga. at Homer, Hudson River nearBroad Bell, Ga.River Ga. Washington, near River Little Butler Gordon,Creek at Fort. Ga. at Augusta, Ga. River Savannah Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02177000 02178400 02182000 02187500 02188500 02189000 02189050 02189100 02189500 02189600 02190000 02190100 02190200 02190500 02191000 02191200 02192000 02193500 02196820 02197000 Table 1. Table [mi

34 87.4 75.1 88.8 81.2 84.1 88.8 93.8 89.0 86.0 86.7 87.6 82.1 84.2 92.6 98.0 96.2 93.1 97.6 86.6 90.2 93.9 Variance Variance (percent) 1.82 2.35 1.88 2.54 2.62 1.82 2.42 2.29 2.23 2.23 2.28 2.39 2.51 2.02 1.74 1.86 1.84 1.62 1.97 1.83 1.96 error (° C) Standard Standard 2.64 2.76 2.79 2.78 2.83 2.70 2.77 2.84 2.81 2.85 2.83 2.85 2.86 2.82 2.75 2.73 2.68 2.73 2.71 2.75 2.95 Phase (radians) coefficient coefficient from observed data 8.2 7.6 6.8 8.2 8.9 8.7 9.3 8.9 9.4 7.7 8.2 8.6 9.0 9.3 9.5 9.5 7.8 8.3 8.3 10.0 10.0 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 16.8 15.3 16.5 17.0 16.4 18.0 16.6 17.6 18.3 17.7 18.5 18.9 18.9 19.9 20.4 20.5 19.8 20.0 17.1 16.2 15.7 27.0 24.0 25.0 28.5 28.5 30.0 30.0 30.0 31.5 30.0 31.0 31.0 29.0 29.6 30.0 30.5 29.8 30.5 28.5 26.0 24.0 (° C) Maximum Observed 4.0 4.0 5.0 2.0 0.0 4.5 2.0 2.5 3.0 3.0 3.0 5.5 5.0 8.0 8.0 6.0 8.0 8.0 3.5 2.0 4.0 (° C) stream temperature Minimum 81 68 80 78 93 98 95 61 52 32 146 155 331 107 121 293 255 101 221 119 111 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 08/57-06/79 11/58-07/76 05/58-07/76 10/54-09/83 07/54-06/79 05/38-12/84 10/54-06/79 08/74-12/84 05/37-10/84 09/54-12/84 02/58-12/84 09/66-11/77 09/66-11/77 09/66-11/77 10/66-11/77 10/66-12/84 10/66-07/70 09/66-07/70 08/70-12/84 10/70-12/84 02/78-08/83 52 96 13 60 20 80 60 0.4 0.1 0.1 0.1 0.1 0.1 0.1 (ft) 330 283 174 112 759 660 720 Altitude Altitude ) ALTAMAHA RIVER BASIN ALTAMAHA 2 55 28 33 473 646 555 970 144 157 161 126 147 29.2 31.7 41.5 11.9 area area (mi 8,650 9,850 1,940 2,370 2,650 Drainage SAVANNAH RIVER BASIN—Continued SAVANNAH OGEECHEE-NEWPORT RIVER BASINS OGEECHEE-NEWPORT 81°30'10" 82°28'06" 82°18'21" 81°57'50" 81°39'05" 81°15'45" 81°52'46" 81°33'21" 81°24'58" 81°53'20" 81°23'07" 81°31'13" 81°27'38" 81°25'37" 81°19'54" 81°16'18" 81°13'09" 81°17'21" 84°18'30" 84°11'12" 84°14'44" ods of analyses, selected station inform selected station of analyses, ods 32°56'20" 33°22'06" 33°10'37" 33°07'05" 32°56'00" 32°31'30" 32°42'38" 32°29'40" 32°11'29" 32°11'05" 31°58'59" 31°48'49" 31°45'16" 31°44'43" 31°42'10" 31°41'43" 31°40'37" 31°39'05" 33°40'46" 33°39'14" 33°29'34" Station name Latitude Longitude Millhaven, Ga. Millhaven, Ga. Ga. Ga. Savannah River at Burtons River FerrySavannah near Ga. Thomson, near Creek Brier Brushy Creek near Wrens, Ga. Brier Ga. Creek near Waynesboro, Brier Creek at Ga. Millhaven, Ga. Clyo, near River Savannah at Scarboro, OgeecheeGa. River Ga. at Oliver, Ogeechee River nearOgeechee Eden, Ga.River Canoochee near Claxton, River Ga. Canoochee Ga. at Fort Stewart, River Peacock Creek at McIntosh, Ga. RiceboroCreek near Riceboro,Ga. Riceboro Creek at Riceboro, Ga. near Seabrook,North River Ga. Newport at Halfmoon Landing, NorthRiver Ga. Newport Ga. Bluff, near Yellow River Timmons near Harris Neck, River Ga. South Newport atSouth Bouldercrest River Road at Atlanta, atSouth State River Highway 155 near Atlanta, Pates Creek at Buster Road Lewis near Flippen, Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02197500 02197520 02197600 02197830 02198000 02198500 02202000 02202190 02202500 02203000 02203519 02203559 02203566 02203570 02203574 02203578 02203585 02203596 02203800 02203965 02204285 Table 1. Table [mi

35 95.3 84.5 78.2 87.7 86.6 86.5 86.7 86.6 85.9 89.9 94.0 86.5 91.3 89.5 79.9 89.3 83.7 87.7 92.8 87.8 87.5 83.2 Variance Variance (percent) 2.10 2.24 2.18 2.18 2.24 2.48 2.18 2.14 2.25 1.93 2.08 2.22 2.23 2.10 2.50 1.27 2.28 1.05 2.13 2.35 1.93 2.43 error (° C) Standard Standard 2.89 2.80 2.80 2.82 2.86 2.80 2.86 2.84 2.83 2.64 2.77 2.86 2.69 2.72 2.92 2.63 2.86 2.63 2.72 2.82 2.87 2.76 Phase (radians) coefficient coefficient from observed data 9.2 9.2 6.9 9.1 9.3 9.5 9.4 9.4 9.3 9.3 9.5 8.4 9.8 8.1 8.6 9.0 8.4 7.7 9.9 10.4 10.3 10.2 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 16.1 15.6 14.4 14.6 15.1 16.0 14.8 15.4 15.4 17.2 14.7 15.4 18.4 18.4 16.8 16.7 16.8 17.0 18.9 17.7 17.0 17.1 26.0 27.5 24.0 28.5 26.0 27.0 27.0 26.5 27.5 27.5 26.0 28.0 34.0 33.0 28.5 26.5 27.0 27.0 32.5 29.0 28.5 28.0 (° C) Maximum Observed 4.0 3.0 2.0 1.5 0.5 2.5 2.0 2.5 2.0 2.0 0.5 1.5 3.2 5.0 4.0 7.0 4.0 6.0 3.5 3.0 4.5 3.5 (° C) stream temperature Minimum 32 30 56 97 31 67 76 42 123 152 183 119 121 122 127 278 113 202 119 133 115 134 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 12/57-09/82 08/70-12/84 10/56-09/76 08/56-11/84 07/74-12/84 12/57-09/82 07/74-06/79 07/74-12/84 05/72-12/84 12/57-12/84 06/60-12/73 07/64-01/85 07/74-12/84 05/37-12/75 08/62-07/76 05/67-12/73 10/55-10/66 11/66-09/74 11/70-12/84 08/74-12/84 04/54-01/74 02/58-06/79 (ft) 565 540 968 806 660 617 600 560 560 419 596 368 270 270 380 365 310 250 200 279 162 Altitude Altitude ) 2 72 29 1.6 456 465 134 236 378 401 440 291 105 156 182 108 area area (mi 1,420 2,230 2,240 2,690 3,350 4,460 Drainage ALTAMAHA RIVER BASIN—-Continued ALTAMAHA 84°00'53" 83°57'29" 84°00'18" 84°04'45" 83°58'43" 83°54'54" 83°53'51" 83°52'43" 83°49'42" 83°50'18" 84°04'17" 83°43'25" 83°39'15" 83°37'14" 83°37'08" 83°50'24" 83°45'30" 83°36'11" 83°32'13" 83°44'21" 83°16'43" ods of analyses, selected station inform selected station of analyses, ods 33°29'48" 33°29'04" 34°00'08" 33°51'11" 33°41'23" 33°36'52" 33°34'12" 33°26'26" 33°26'58" 33°18'28" 33°15'50" 33°05'59" 32°52'11" 32°50'19" 32°58'20" 32°52'02" 32°48'32" 32°40'17" 32°32'33" 32°27'20" 31°59'47"

Station name Latitude Longitude Snapping Shoals, Ga. Ga. Stewart, Road nearGa. Stewart, Ga. South River nearSouth McDonough, River Ga. atSouth State River Highway 81 at CreekWildcat near Lawrenceville, Ga. Ga. Snellville, near River Yellow (Conyers Intake) River at Conyers, Ga. Yellow near Covington, River Ga. Yellow at Porterdale, River Ga. Yellow at State River Highway 212 near Yellow Bridge Factory Newton River Alcovy Ga. Jackson, near River Ocmulgee near Jackson, River Ga. Towaliga Ga. Juliette, near Creek Falling at Macon, Intake) (Macon River Ocmulgee at Macon, Ga. Ocmulgee River Ga. Creek near Gray, Walnut Macon,Ga. Creekabove Tobesofkee Creek near Macon, Ga.Tobesofkee Robins, Ga. near Warner Ocmulgee River Ga. Bonaire, near River Ocmulgee Big Indian Ga. Creek at Perry, Ga. Abbeville, at River Ocmulgee Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02204500 02204520 02205000 02206500 02207300 02207500 02207540 02208005 02209260 02210500 02211300 02212600 02212950 02213000 02213050 02213470 02213500 02213700 02214265 02214500 02215260 Table 1. Table [mi

36 88.5 89.4 87.7 90.5 88.8 89.5 85.6 75.3 83.8 89.0 91.5 87.3 86.2 92.1 92.0 80.4 87.5 89.1 84.0 93.5 Variance Variance (percent) 1.9 2.01 2.10 2.38 2.19 2.26 2.28 2.20 2.51 2.14 1.95 1.97 1.92 2.16 1.98 2.27 2.18 2.15 2.53 1.24 error (° C) Standard Standard 2.76 2.71 2.80 2.90 2.85 2.79 2.78 2.83 2.87 2.62 2.58 2.72 2.92 2.69 2.72 2.85 2.78 2.92 2.78 2.76 Phase (radians) coefficient coefficient from observed data 9.9 8.0 9.4 9.6 9.8 9.2 7.2 7.5 8.9 9.4 9.8 8.2 9.3 7.5 8.8 9.1 9.5 10.0 10.4 10.1 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 19.0 13.9 15.5 14.8 15.4 16.5 16.0 15.2 14.6 17.8 18.1 18.5 16.7 18.0 18.2 17.2 19.3 18.0 18.5 19.7 31.0 24.0 27.0 26.0 29.5 30.0 26.5 25.0 23.5 30.0 29.5 31.0 27.0 29.0 31.0 28.0 31.0 28.0 31.0 32.0 (° C) Maximum Observed 3.0 3.0 3.0 1.0 1.0 2.5 0.5 3.5 3.0 3.0 3.0 5.0 5.0 5.5 3.0 4.5 4.0 5.0 3.0 5.0 (° C) stream temperature Minimum 69 82 64 250 112 158 116 120 219 149 143 117 273 117 126 102 152 146 212 117 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 06/54-12/84 10/56-06/74 08/56-10/77 07/74-12/84 07/74-12/84 07/56-12/84 07/56-07/76 12/60-08/76 08/56-12/73 05/37-12/84 07/74-12/84 02/79-12/84 08/58-12/73 11/54-11/76 10/73-12/84 08/54-03/84 12/57-12/84 07/79-12/84 07/54-10/82 08/74-12/84 87 62 90 74 40 (ft) 784 556 580 530 410 424 395 498 231 200 170 324 149 148 262 Altitude Altitude ) 2 24 31 398 270 783 436 300 18.2 16.6 62.9 area area (mi 5,180 1,090 2,950 3,200 3,770 4,400 4,440 1,110 11,600 13,600 Drainage ALTAMAHA RIVER BASIN—-Continued ALTAMAHA 82°40'26" 83°43'11" 83°25'22" 83°22'56" 83°19'36" 83°16'22" 83°20'58" 83°01'34" 83°39'43" 83°12'51" 83°11'24" 82°57'30" 83°25'04" 82°53'41" 82°51'45" 83°08'49" 82°21'13" 82°12'43" 82°10'39" 81°50'19" ods of analyses, selected station inform selected station of analyses, ods 31°55'06" 34°11'34" 33°56'48" 33°58'28" 33°51'21" 33°34'52" 33°36'31" 33°23'12" 33°24'56" 33°04'58" 33°01'45" 32°46'54" 32°48'15" 32°32'40" 32°29'05" 32°29'38" 31°56'20" 32°09'36" 32°04'42" 31°39'59" Station name Latitude Longitude Ga. Ga. Watkinsville, Ga. Toombsboro, Dublin, Ga. Ohoopee, Ga. Ocmulgee River at Lumber City, Ga. atCity, Lumber Ocmulgee River Ga. Talmo, at Creek Allen Ga. Athens, near River Oconee Middle Athens, at Intake) (Athens River Oconee North atOconee Barnett River Shoals near Ga. Greensboro, near River Oconee Apalachee near Buckhead, River Ga. Whitten Creek near Sparta, Ga. Murder Creek near Monticello, Ga. Ga. at Milledgeville, River Oconee near Ga. Hardwick, Oconee River atOconee State River Highway 57 near Big Sandy Creek near Ga. Jeffersonville, atOconee Dublin, River Ga. near 16 Highway at Interstate River Oconee Ga. Rocky Creek near Dudley, Ga. near Baxley, AltamahaRiver Pendelton Creek at State Highway 86 below Ohoopee near Reidsville, River Ga. near Jesup,Altamaha Ga. River Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02215500 02217000 02217500 02217740 02218000 02218500 02219500 02220550 02221000 02223000 02223040 02223250 02223300 02223500 02223600 02224000 02225000 02225470 02225500 02225990 Table 1. Table [mi

37 92.7 93.9 85.9 91.2 86.8 84.3 86.9 81.9 88.2 90.3 88.2 87.7 84.2 81.6 86.4 84.7 79.5 99.9 88.9 Variance Variance (percent) 2.09 1.94 2.10 1.86 2.43 2.41 2.44 2.33 2.23 2.36 2.27 2.22 2.33 2.34 2.27 2.24 2.59 1.90 2.37 error (° C) Standard Standard 2.75 2.74 2.82 2.71 2.87 2.86 2.86 2.95 2.82 2.77 2.83 2.78 2.78 2.69 2.77 2.75 2.75 2.76 2.81 Phase (radians) coefficient coefficient from observed data 9.6 8.0 9.3 9.5 8.9 9.5 8.4 8.4 9.1 8.5 8.1 8.5 7.8 8.7 8.3 8.3 8.7 8.9 10.0 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 19.4 19.9 18.4 19.7 18.6 19.8 18.9 17.9 18.9 20.0 19.9 18.6 19.6 19.4 18.1 18.5 17.7 18.8 19.4 31.0 32.0 29.5 31.5 31.0 31.0 31.5 30.5 32.0 34.0 31.0 29.5 31.5 29.0 29.5 29.0 28.0 29.0 31.0 (° C) Maximum Observed 3.3 5.0 6.0 5.0 4.0 5.0 4.0 4.5 6.0 5.0 4.0 5.5 4.0 4.0 4.0 4.5 2.0 8.0 6.0 (° C) stream temperature Minimum 65 34 25 95 215 113 182 166 116 188 120 103 163 258 258 171 164 121 115 of Number observations ation, and harmonic properties—Continued

of record record Period analyzed 05/37-10/79 11/74-12/84 12/58-07/84 12/70-12/84 08/74-12/84 05/37-08/74 08/74-12/84 01/55-06/82 01/55-09/83 05/54-10/84 08/57-11/84 03/53-07/84 01/54-08/74 07/79-12/84 11/74-12/84 11/74-12/84 08/77-06/82 10/55-03/61 04/61-07/74 25 40 19 70 66 52 58 15 92 77 5.0 (ft) 136 208 200 190 170 252 171 Altitude Altitude ) 2 10 210 139 646 663 520 552 145 577 area area (mi 1,160 1,200 1,350 2,790 1,260 1,400 13,600 13,600 14,000 Drainage SATILLA–ST MARY’S RIVER BASINS MARY’S SATILLA–ST ALTAMAHA RIVER BASIN—Continued ALTAMAHA SUWANNEE–OCHLOCKONEE–AUCILLA RIVER BASINS RIVER SUWANNEE–OCHLOCKONEE–AUCILLA 81°49'41" 81°45'55" 81°50'18" 81°36'20" 82°23'33" 82°19'29" 82°09'45" 82°27'50" 82°03'17" 81°52'03" 82°33'38" 83°11'33" 83°02'00" 83°28'33" 83°17'22" 83°20'23" 83°33'38" 83°32'38" ods of analyses, selected station inform selected station of analyses, ods 31°39'16" 31°37'24" 31°34'00" 31°25'37" 31°18'17" 31°14'17" 31°13'00" 31°34'00" 31°27'04" 31°13'16" 30°40'50" 31°23'03" 30°42'14" 31°26'33" 30°55'57" 30°51'00" 31°26'21" 31°09'18"

Station name Latitude Longitude Hoboken, Ga. Ga. Valdosta, near Altamaha River Ga. at Doctortown, Altamaha River Ga. near Gardi, AltamahaRiver CreekPenholoway near Jesup, Ga. Ga. City, Everett at River Altamaha Ga. Waltertown, at River Satilla Ga. Waycross, near River Satilla Satilla at State Highways River 15 and 121 near Hurricane Creek near Alma, Ga. Ga. Offerman, near River Satilla Little Ga. Atkinson, at River Satilla Ga. Fargo, at River Suwannee nearAlapaha Alapaha, River Ga. atAlapaha Statenville, Ga. River at U.S.Ga. Highway 82 near Tifton, River New Ga. nearWithlacoochee Valdosta, River at StateWithlacoochee River Highway 94 Ga. Tifton, near 82 Highway U.S. at River Little Ga. Adel, near River Little Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02226000 02226010 02226100 02226160 02226475 02226500 02226582 02227000 02227500 02228000 02314500 02316000 02317500 02317718 02317749 02317757 02317800 02318000 Table 1. Table [mi

38 89.2 86.1 83.2 79.3 89.4 81.4 85.8 99.7 86.3 84.5 41.9 58.1 82.3 79.3 89.0 68.3 92.1 83.4 86.2 79.4 Variance Variance (percent) 2.01 2.24 2.26 2.48 2.31 2.00 2.20 1.93 2.18 2.33 0.95 1.31 2.23 1.81 2.44 2.62 2.17 2.41 2.10 2.80 error (° C) Standard Standard 2.77 2.76 2.74 2.74 2.77 2.81 2.81 2.77 2.82 2.76 2.17 2.53 2.78 2.69 2.80 2.69 2.85 2.72 2.69 2.84 Phase (radians) coefficient coefficient from observed data 9.0 8.6 8.1 8.2 8.6 7.4 8.5 8.4 8.7 7.9 1.8 3.6 7.8 6.1 9.7 6.6 9.4 9.4 7.6 8.9 (° C) Harmonic properties computed properties Harmonic Amplitude 9.2 (° C) Mean 18.9 18.1 18.5 17.6 18.4 17.7 17.8 13.9 14.7 14.1 11.6 14.3 13.1 16.0 15.7 15.3 16.4 16.4 15.1 29.0 29.5 29.0 29.5 30.5 27.0 29.0 25.0 26.0 25.0 14.5 18.0 24.0 28.5 31.0 30.2 27.0 30.0 28.0 27.0 (° C) Maximum Observed 4.0 4.5 3.0 3.0 2.5 3.0 2.0 2.0 0.5 1.0 5.0 2.0 1.0 2.0 0.0 5.0 0.5 3.5 4.0 0.5 (° C) stream temperature Minimum 93 65 86 64 55 115 118 231 110 115 123 139 167 123 150 360 306 123 339 380 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 08/57-12/84 11/74-12/84 11/74-12/84 07/79-12/84 04/54-12/84 05/54-07/74 08/74-12/84 09/57-08/76 02/68-11/84 10/56-9/76 05/57-08/77 10/57-09/76 05/60-09/76 11/57-09/79 07/59-12/84 07/75-12/84 05/57-12/84 10/63-07/70 07/65-12/84 07/74-05/79 84 94 50 (ft) 150 134 159 100 905 878 961 750 764 745 857 812 719 940 1,220 1,129 1,129 Altitude Altitude ) 2 60 72 70 5.3 278 104 550 930 150 315 153 246 86.8 area area 1450 (mi CHATTAHOOCHEE RIVER BASIN CHATTAHOOCHEE 1,480 1,490 1,060 1,170 1,600 2,060 Drainage 83°27'06" 83°31'33" 83°18'41" 83°48'13" 84°02'44" 84°15'46" 84°14'12" 83°38'09" 83°37'14" 83°56'23" 84°05'37" 84°12'07" 84°16'10" 84°27'16" 84°24'28" 84°29'43" 84°36'53" 84°30'40" 84°40'25" 84°47'35" SUWANNEE-OCHLOCKONEE-AUCILLA RIVER BASINS—Continued SUWANNEE-OCHLOCKONEE-AUCILLA ods of analyses, selected station inform selected station of analyses, ods 30°47'33" 30°47'10" 30°38'07" 31°08'31" 30°52'32" 30°51'54" 30°43'53" 34°34'37" 34°32'27" 34°31'41" 34°07'34" 33°59'50" 34°03'02" 33°51'33" 33°49'10" 33°48'32" 33°46'22" 33°39'40" 33°39'24" 33°37'20"

Station name Latitude Longitude Quitman, Ga. Ga.Dahlonega, Ga. Atlanta, near Ga. Withlacoochee River nearWithlacoochee Quitman, River Ga. Okapilco Creek at U.S. Highway 84 at Ga. Clyattsville, near River Withlacoochee Ochlockoneenear Moultrie, River Ga. Ochlockoneenear Thomasville, River Ga. CreekTired near Cairo, Ga. Ga. Ochlockoneenear Calvary, River Chattahoochee near Leaf, River Ga. Chattahoochee near Cornelia, River Ga. Chestatee at State River Highway 52 near Chattahoochee near Buford, River Ga. Chattahoochee near Norcross, River Ga. Ga. Alpharetta, near Creek Big Chattahoochee at Atlanta, River Ga. Peachtree Creek at Atlanta, Ga. Chattahoochee at Interstate River Highway 285 Ga. Austell, near Creek Sweetwater North CampFork Creek at Atlanta, Ga. Chattahoochee near Ga. Fairburn, River at State Dog River Highway 166 near Fairplay, Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02318500 02318725 02318960 02327205 02327500 02328000 02328200 02331000 02331600 02333500 02334500 02335000 02335700 02336000 02336300 02336502 02337000 02337100 02337170 02337438 Table 1. Table [mi

39 92.7 89.5 87.7 92.6 88.6 88.5 98.6 86.4 92.3 96.0 92.9 85.1 88.6 78.4 90.7 88.0 88.2 89.8 88.8 91.1 Variance Variance (percent) 1.60 2.18 2.34 2.11 2.31 2.37 1.70 2.31 1.96 1.64 2.23 2.04 1.31 2.40 1.82 2.23 2.08 2.00 2.15 2.12 error (° C) Standard Standard 2.78 2.73 2.72 2.75 2.85 2.81 2.62 2.89 2.83 2.68 2.82 2.88 2.80 2.66 2.67 2.84 2.80 2.82 2.86 2.87 Phase (radians) coefficient coefficient from observed data 7.9 7.9 8.8 9.3 9.2 9.1 9.0 9.1 9.5 8.3 6.8 9.0 9.3 9.2 9.0 9.5 9.5 10.4 10.3 10.0 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 15.1 16.9 17.8 18.7 15.6 17.2 17.2 16.1 15.4 18.5 18.2 17.0 18.9 18.9 19.5 15.9 15.8 14.2 15.7 15.8 26.0 30.0 28.9 33.0 27.0 31.0 28.0 27.5 26.5 30.0 30.5 25.0 29.0 30.0 31.5 27.0 27.0 25.0 27.5 27.0 (° C) Maximum Observed 3.5 1.5 2.0 2.5 1.0 4.0 1.0 0.0 2.0 6.0 0.0 8.0 7.8 8.0 5.5 1.5 0.5 3.0 1.0 1.0 (° C) stream temperature Minimum 69 38 48 93 184 311 170 273 104 163 166 117 103 173 127 120 113 111 111 111 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 10/59-07/84 02/58-12/84 02/58-12/84 07/74-12/84 08/56-09/70 09/57-09/74 10/74-12/84 07/74-12/84 08/56-06/74 10/40-09/74 04/65-09/83 08/62-11/73 11/40-04/58 01/64-07/74 10/74-12/84 05/58-12/84 07/75-12/84 07/60-09/70 07/75-12/84 07/75-12/84 72 63 60 (ft) 833 682 624 600 601 552 580 550 183 230 224 780 760 800 740 720 Altitude Altitude FLINT RIVER BASIN ) 2 36 75 62 70 60 17 182 342 100 194 39.3 area area (mi 2,430 2,680 2,700 3,550 4,670 8,040 8,340 8,510 Drainage CHATTAHOOCHEE RIVER BASIN—Continued CHATTAHOOCHEE 84°55'42" 84°54'04" 85°06'00" 85°06'39" 85°03'40" 85°10'56" 85°08'43" 85°04'08" 84°59'52" 84°49'12" 84°48'12" 85°05'59" 85°02'50" 85°00'19" 84°22'35" 84°23'44" 84°25'39" 84°23'24" 84°23'36" ods of analyses, selected station inform selected station of analyses, ods 33°31'46" 33°28'37" 33°16'45" 33°04'42" 33°05'27" 32°53'10" 32°54'37" 32°44'28" 32°27'45" 32°24'48" 31°56'03" 31°17'02" 31°06'59" 30°58'39" 33°32'14" 33°29'13" 33°31'00" 33°23'08" 33°18'33"

Station name Latitude Longitude at Franklin,Ga. LaGrange, Ga. Jonesboro, Ga. Ga. Fayetteville, Ga. Snake Creek near Ga. Whitesburg, Chattahoochee near Ga. Whitesburg, River Chattahoochee at U.S. River Highway 27 Chattahoochee (LaGrange River Intake) near Creek near LaGrange, Ga. Yellowjacket Point, Ga. Chattahoochee at West River Point,Long Ga. Cane Creek near West Mountain Oak Creek near Hamilton, Ga. Chattahoochee at Columbus, Ga. River Upatoi Creek near Columbus, Ga. PataulaCreek near Lumpkin,Ga. Chattahoochee at Columbia, River Ala. Chattahoochee at Alaga River Ala. Chattahoochee near Steam River Mill, Ga. atFlint State River Highway 138 near near 54 Highway State at River Flint Camp Creek near Ga. Fayetteville, at AckertFlint Road River near Inman, Ga. Griffin, above 92 Highway State at River Flint Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02337500 02338000 02338500 02338720 02339000 02339500 02339720 02340500 02341500 02341800 02343200 02343500 02344000 02344040 02344180 02344190 02344300 02344380 02344400 Table 1. Table [mi

40 91.8 87.2 89.4 87.8 87.2 87.5 83.8 87.3 81.2 92.4 89.9 94.5 83.0 86.9 91.7 86.8 93.7 92.5 89.1 88.4 Variance Variance (percent) 2.06 2.25 2.20 2.48 1.65 2.16 2.17 2.15 2.52 2.18 1.82 1.83 1.96 2.22 2.02 1.98 2.07 1.90 2.04 1.88 error (° C) Standard Standard 2.85 2.79 2.80 2.82 2.90 2.87 2.91 2.90 2.91 2.77 2.72 2.71 2.90 2.82 2.74 2.73 2.81 2.79 2.82 2.77 Phase (radians) coefficient coefficient from observed data 9.8 9.8 6.2 9.0 7.3 9.9 8.0 9.3 9.8 8.9 7.2 7.6 8.7 8.9 8.1 7.5 8.0 8.0 10.0 10.2 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 16.0 15.3 16.7 17.6 17.1 18.0 17.2 18.1 16.9 19.4 19.6 19.3 17.3 18.4 19.9 19.5 18.2 13.9 13.6 13.7 28.0 26.5 28.5 30.0 25.0 30.0 28.0 28.5 27.0 31.5 31.0 29.0 26.0 28.5 30.0 30.0 28.0 24.0 24.0 25.0 (° C) Maximum Observed 1.5 2.0 3.0 3.0 8.0 4.0 3.5 3.0 3.0 5.5 5.0 6.0 6.5 4.0 6.0 5.5 6.0 0.0 2.0 0.5 (° C) stream temperature Minimum 98 55 68 95 157 103 189 103 245 124 169 171 120 205 152 120 128 154 121 175 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 08/56-07/76 09/64-07/76 07/56-06/74 04/54-06/79 04/54-11/73 05/54-12/84 07/54-06/82 07/79-12/84 05/54-07/84 05/54-12/84 08/74-12/84 08/56-10/84 10/54-11/73 04/54-07/84 04/54-07/73 07/74-12/84 08/57-07/78 06/57-08/75 06/57-07/74 05/63-08/83 58 57 86 (ft) 711 729 605 335 366 256 286 220 338 150 140 110 213 150 1,255 1,242 1,216 Altitude Altitude COOSABASIN RIVER ) 2 93 45 88 272 101 186 197 188 620 485 134 236 FLINT RIVER BASIN—Continued area area (mi 1,850 2,900 3,390 5,310 5,340 5,740 7,570 7,570 Drainage 84°25'45" 84°31'25" 84°21'45" 84°13'57" 84°15'58" 84°02'38" 83°54'03" 83°58'39" 84°32'53" 84°08'39" 84°08'16" 84°20'06" 84°40'43" 84°32'52" 84°34'48" 84°36'38" 84°44'18" 84°27'20" 84°28'40" 84°30'31" ods of analyses, selected station inform selected station of analyses, ods 33°14'39" 33°19'10" 32°54'15" 32°43'17" 32°28'00" 32°17'53" 32°11'44" 32°03'31" 32°03'09" 31°35'39" 31°26'39" 31°18'34" 31°33'17" 31°22'58" 30°54'41" 30°53'34" 31°02'23" 34°40'53" 34°41'06" 34°40'18"

Station name Latitude Longitude Creek near Butler, Ga.Creek near Butler, Ga. Vienna, Ga. Bainbridge, at Flint River near Griffin, Ga. Griffin, near River Flint Line Creek near Senoia, Ga. Ga. Thomaston, near Creek Potato Ga. Culloden, near River Flint Rambulette below Creek Whitewater at Montezuma,Flint River Ga. Creek at Byromville,Turkey Ga. near 27 Highway State at River Flint Kinchafoonee Creek at Preston, Ga. Ga. Albany, at River Flint Ga. Putney, near Intake) (Putney River Flint Ga. at Newton, River Flint Ga. Edison, near Creek Pachitla CeekrIchawaynochaway at Milford, Ga. Ga. Bainbridge, at River Flint 0.8Flint mile State River below Docks Ga. City, Iron near Creek Spring Ga. Cartecay near Ellijay, River Ga. Ellijay, at River Ellijay Ga. Ellijay, near River Coosawattee Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02344500 02344700 02346500 02347500 02349000 02349500 02349900 02350001 02350600 02352500 02352790 02353000 02353400 02353500 02356000 02356015 02357000 02379500 02380000 02380500 Table 1. Table [mi

41 85.4 93.7 81.5 85.9 94.4 92.5 84.4 90.2 95.1 89.1 92.6 85.4 97.3 96.0 90.2 84.3 92.1 92.9 89.0 94.2 87.3 95.1 Variance Variance (percent) 2.09 1.48 2.22 2.30 1.78 1.96 2.27 2.30 2.00 2.12 1.89 1.82 2.01 2.06 1.90 1.85 1.97 2.35 2.54 1.57 2.13 1.57 error (° C) Standard Standard 2.82 2.76 2.82 2.78 2.56 2.78 2.75 2.82 2.76 2.77 2.66 2.76 2.74 2.68 2.74 2.75 2.81 2.79 2.78 2.39 2.78 2.54 Phase (radians) coefficient coefficient from observed data 7.9 9.6 7.9 9.4 8.8 9.9 9.0 9.9 9.8 9.3 7.2 8.2 6.8 8.9 8.3 9.7 9.1 8.6 8.7 10.4 10.3 10.0 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 14.5 15.1 15.0 15.2 14.9 15.1 14.7 16.1 15.8 15.0 15.3 14.8 16.1 16.0 13.6 13.3 14.2 14.4 15.9 15.1 14.2 15.7 25.5 26.5 24.5 27.0 29.5 27.0 26.0 30.5 28.0 27.0 27.0 24.5 30.0 28.5 24.5 22.0 27.0 25.0 28.5 26.0 25.0 26.5 (° C) Maximum Observed 1.5 5.0 3.0 1.5 2.5 1.5 1.5 0.5 1.0 2.0 2.5 4.0 2.0 2.0 1.5 3.5 1.5 1.5 3.0 0.0 3.0 4.0, (° C) stream temperature Minimum 32 92 90 91 46, 132 109 114 119 202 279 117 111 113 156 128 119 163 212 120 118 117 of Number observations ation, and harmonic properties—Continued

of record record Period analyzed 05/59-07/74 07/65-12/72 07/57-09/72 06/57-12/72 08/74-12/84 07/74-12/84 07/60-06/83 06/57-12/84 08/74-12/84 09/57-12/72 08/74-12/84 05/60-04/82 09/57-12/73 08/74-12/84 09/56-08/84 06/58-06/74 06/57-10/84 08/59-09/64 08/56-06/75 01/58-11/84 06/59-07/74 08/74-12/84 (ft) 651 759 616 610 650 689 622 610 604 602 710 562 562 845 898 687 690 650 1,051 1,050 1,150 Altitude Altitude ) 2 21 64 36 22 60 25 6.2 521 831 861 308 687 706 107 605 area area COOSA RIVER BASIN—Continued (mi 1,602 1,620 2,115 2,145 1,119 1,612 Drainage 84°35'30" 84°41'44" 84°46'46" 84°51'37" 84°54'03" 84°52'30" 84°46'12" 84°55'42" 84°56'02" 84°56'29" 84°56'49" 85°09'16" 85°08'30" 85°10'24" 84°03'21" 84°08'47" 84°29'47" 84°23'18" 84°44'28" 84°57'02" 84°55'44" ods of analyses, selected station inform selected station of analyses, ods 34°28'04" 34°36'13" 34°21'32" 34°34'35" 34°32'28" 34°47'20" 34°43'00" 34°40'00" 34°35'36" 34°34'42" 34°34'17" 34°34'04" 34°18'02" 34°16'13" 34°22'57" 34°25'13" 34°14'23" 34°07'09" 34°09'47" 34°04'27" 34°11'28" Station name Latitude Longitude Ga. Resaca, Ga. Ga. Cartersville, Scarecorn Creek at Hinton, Ga. at Carters,Coosawattee River Ga. Rock Creek near Fairmount, Ga. nearCoosawattee Pine River Chapel, Ga. nearCoosawattee Calhoun, River Ga. Conasauga (Dalton River Intake) near Dalton, Ga. Chatsworth, near Creek Holly Conasauga Ga. at Tilton, River Conasauga near Resaca, River Ga. Oostanaula at Resaca, River Ga. Oostanaula at Interstate River Highway 75 at Armuchee Creek nearr Subligna,West Ga. at Rome,Oostanaula Ga. River (RomeOostanaula Intake) at Rome, River Ga. Ga. near Dawsonville, River Etowah Shoal Creek Ga. near Dawsonville, Ga. Canton, at River Etowah Ga. Roswell, near River Little above Dam Allatoona at River Etowah Hills CreekGa. near Taylorsville, Kingston, Ga. above River Etowah Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02382000 02382500 02383000 02383500 02383540 02384748 02385800 02387000 02387050 02387500 02387502 02388000 02388500 02388520 02389000 02389300 02392000 02392500 02394000 02394950 02394980 Table 1. Table [mi

42 88.3 91.0 93.5 88.0 95.2 85.2 89.0 88.6 88.3 89.9 79.0 83.8 73.2 89.6 64.0 85.5 90.0 92.6 Variance Variance (percent) 2.00 1.81 1.73 1.45 1.74 1.83 2.01 1.97 2.33 2.09 2.13 2.09 2.44 2.04 2.37 2.21 2.03 1.76 error (° C) Standard Standard 2.68 2.61 2.65 2.79 2.65 2.74 2.79 2.80 2.83 2.85 2.81 2.81 2.12 2.77 2.12 2.82 2.79 2.77 Phase (radians) coefficient coefficient from observed data 8.4 8.9 9.6 7.0 7.2 8.3 8.5 9.4 9.1 6.5 7.3 6.7 8.1 5.6 7.9 9.0 8.5 10.4 (° C) Harmonic properties computed properties Harmonic Amplitude (° C) Mean 16.7 15.9 16.2 15.9 18.3 15.6 15.7 14.5 15.4 15.6 12.7 13.2 12.4 12.9 12.4 13.5 14.8 15.3 26.0 28.0 28.0 25.5 31.0 26.0 26.5 25.0 29.0 26.5 24.0 24.0 25.0 25.0 23.0 26.0 26.0 26.0 (° C) Maximum Observed 4.0 3.0 2.5 3.5 5.0 1.5 2.0 2.0 0.0 1.0 0.0 0.0 3.5 0.5 3.5 0.5 1.0 1.0 (° C) stream temperature Minimum 51 80 80 236 267 278 116 290 119 138 117 270 244 158 297 125 218 119 of Number observations ation, and harmonic properties—Continued of record record Period analyzed 10/69-09/84 09/57-12/84 07/57-12/84 06/57-12/84 08/74-12/84 07/57-12/84 08/74-12/84 05/59-08/75 07/74-11/84 07/74-12/84 08/51-06/82 08/51-06/82 09/51-07/74 01/51-06/84 01/51-07/74 01/51-06/74 08/74-11/84 08/74-12/84 (ft) 610 562 553 725 550 613 605 920 919 680 679 1,110 1,933 1,812 1,599 1,782 1,539 1,450 Altitude Altitude ) TENNESSEE RIVER BASIN 2 20 46 75 71 115 192 281 272 245 215 177 233 198 148 area area COOSA RIVER BASIN—Continued (mi 1,634 1,819 4,040 4,362 Drainage 84°58'44" 85°09'30" 85°15'24" 85°18'41" 85°26'46" 85°20'19" 85°26'43" 85°07'03" 85°20'11" 85°16'45" 83°43'01" 83°56'10" 84°05'25" 84°14'24" 84°17'07" 84°23'12" 85°08'42" 85°12'20" ods of analyses, selected station inform selected station of analyses, ods 34°12'24" 34°15'26" 34°12'01" 34°03'38" 34°11'54" 34°28'03" 34°20'08" 33°47'51" 33°44'27" 33°29'34" 34°54'17" 34°50'28" 34°57'55" 34°47'24" 34°53'14" 34°58'53" 34°58'39" 34°57'26" Station name Latitude Longitude Etowah River near Kingston, Ga. River Etowah at Rome, Ga. River Etowah near Rome, Ga. Coosa River Cedar Creek near Cedartown, Ga. at State Line,Ala.-Ga.Coosa River Ga. Summerville, at River Chattooga Ga. Chattoogaville, at River Chattooga Ga. Buchanan, near River Little Ga. Tallapoosa, below River Tallapoosa Ga. Bowdon, below River Tallapoosa Little Ga. at Presley, River Hiwassee near Blairsville, NottelyGa. River Nottelyat Nottely River Dam near Ivylog, Ga. near Dial,Ga. River Toccoa near BlueRidge, Ga. River Toccoa Fightingtown Creek at McCaysville, Ga. Ga. at Graysville, Creek Chickamauga South Ga. Chickamauga Creek nearWest Lakeview, Periodic stream-temperature stations, peri Periodic stream-temperature stations, , square miles; ft, feet; ° C, degrees Celsius] ° C, degrees ft, feet; miles; , square 2 Station number 02395000 02396000 02397000 02397500 02397530 02398000 02398037 02411800 02411930 02413210 03545000 03550500 03553500 03558000 03559000 03560000 03566800 03567340 Table 1. Table [mi

43 98.1 97.9 97.0 96.4 96.7 98.2 98.0 97.3 97.4 96.7 96.9 97.2 97.1 94.7 95.8 95.5 96.7 97.4 98.6 98.6 98.6 96.9 96.9 96.9 97.9 98.0 98.0 Variance Variance (percent) .62 .67 .64 .75 .70 .58 .63 .68 .69 .56 .61 .59 .82 .73 .45 .53 .48 .74 .78 .75 .54 .61 .56 1.03 1.11 1.09 1.08 error (° C) Standard 2.80 2.72 2.43 2.37 2.40 2.6 2.6 2.75 2.75 2.80 2.74 2.72 2.73 2.89 2.83 2.86 2.85 2.83 2.71 2.71 2.71 2.72 2.73 2.72 2.73 2.73 2.73 Phase (radians) coefficient coefficient 8.2 7.3 7.3 7.0 7.1 7.9 7.9 8.9 8.7 8.7 8.8 8.7 8.4 8.6 8.6 8.6 8.5 9.0 8.9 9.0 9.5 9.4 9.4 10.1 10.5 10.4 10.5 (° C) Amplitude

Harmonic properties computed from observed data 13.9 11.0 17.1 16.0 16.6 17.8 17.4 18.2 17.4 18.5 22.2 21.0 21.6 16.5 14.3 15.4 17.0 15.0 19.7 18.5 19.1 20.9 19.6 20.2 20.7 19.6 20.1 (° C) Mean 2,06 Days 5,167 5,164 2,335 2,332 2,324 4,073 4,083 3,154 3,154 1,965 1,965 1,964 2,110 2,099 2,099 4,599 4,598 4,969 4,963 4,961 1,802 1,801 1,799 4,993 4,980 4,975 mean mean mean mean mean mean mean minimum minimum minimum minimum minimum minimum minimum minimum minimum minimum maximum maximum maximum maximum maximum maximum maximum maximum maximum maximum Statistic n, and harmonicn, and properties of record record Period 1964-79 1964-79 1973-80 1973-80 1973-80 1960-74 1960-74 1972-81 1972-81 1975-81 1970-76 1970-76 1970-76 1972-78 1972-78 1972-79 1965-79 1965-79 1970-85 1970-85 1970-85 1970-76 1970-76 1970-76 1969-85 1969-85 1969-85 analyzed 0.1 0.1 97 54 20 62 646 368 250 (ft) 1,869 Altitude Altitude ) 2 lected station informatio 56.5 72.2 157 185 area (mi 7,508 8,650 2,650 2,690 11,600 14,000 Drainage " 11 ' 36 ° 83°31'50" 81°56'35" 81°30'10" 81°24'58" 81°16'18" 83°46'45" 83°43'25" 82°21'13" 81°36'20" Longitude 83 " 59 ' 05 ° Latitude ns, periods of analyses,ns, periods se of 34°53'25" 33°22'25" 32°56'20" 32°11'29" 31°41'43" 33°38'24" 32°40'17" 31°56'20" 31°25'37" 33

lsius; ft, feet; —, no data] no —, feet; ft, lsius; Station name Station near Millhaven, Ga. near Millhaven, Ga. Tallulah River near Clayton, River Ga. Tallulah at Augusta, Ga. River Savannah at Burtons Ferry River Savannah Ogeecheenear Eden, River Ga. at Halfmoon Landing, River North Newport Ga. Covington, above River Alcovy Ga. Juliette, near Creek Falling Robins, Ga. nearOcmulgee Warner River Ga. near Baxley, Altamaha River Ga. City, at Everett Altamaha River Stream-temperature daily record statio Stream-temperature daily , square miles; ° C, degrees , Ce square miles; ° C, degrees 2 Station number 02178400 02197000 02197500 02202500 02203578 02208450 02212600 02213700 02225000 02226160 Table 2. [mi

44 97.5 97.3 97.4 94.2 97.1 96.2 96.8 97.2 96.6 97.0 96.2 96.8 96.7 97.2 96.1 96.7 96.3 96.1 96.2 97.7 97.7 97.8 98.0 97.9 97.8 94.6 94.6 94.6 Variance Variance (percent) .61 .71 .67 .85 .64 .74 .67 .73 .80 .75 .77 .96 .86 .91 .98 .94 .86 .88 .84 .61 .68 .83 1.16 0.97 1.01 1.07 1.12 1.08 error (° C) Standard 2.83 2.82 2.83 2.65 2.67 2.68 2.68 2.71 2.70 2.70 2.82 2.85 2.84 2.55 2.50 2.52 2.58 2.56 2.56 2.77 2.77 2.77 2.70 2.70 2.66 2.76 2.77 2.76 Phase (radians) coefficient coefficient 9.4 9.2 9.3 6.5 7.5 6.7 7.1 8.0 7.5 7.7 9.8 9.1 9.3 8.0 7.6 7.8 7.9 7.8 7.9 8.8 8.7 9.5 7.5 7.5 7.5 10.5 10.3 10.4 (° C) Amplitude Harmonic properties computed from observed data 20.7 19.6 20.1 20.1 17.4 15.3 16.3 17.0 15.6 16.2 17.5 14.9 16.1 15.5 13.7 14.6 15.4 14.3 14.8 17.3 15.7 16.5 16.1 15.2 15.7 15.7 14.6 15.1 (° C) Mean 2,426 2,426 2,425 3,016 3,249 3,248 3,248 2,073 2,071 2,071 1,895 1,892 1,894 2,428 2,428 2,428 2,351 2,351 2,351 2,843 2,835 2,834 5,439 5,439 2,371 1,751 1,751 1,751 mean mean mean mean mean mean mean mean mean random and harmonic properties—Continued minimum minimum minimum minimum minimum minimum minimum minimum minimum maximum maximum maximum maximum maximum maximum maximum maximum maximum Statistic Days of record record Period 1974-81 1974-81 1974-81 1965-77 1975-85 1975-85 1975-85 1975-84 1975-84 1975-84 1978-84 1978-84 1978-84 1974-81 1974-81 1974-81 1974-81 1974-81 1974-81 1975-85 1975-85 1975-85 1967-84 1967-84 1976-84 1971-76 1971-76 1971-76 analyzed 15 40 719 682 635 630 616 622 604 845 (ft) Altitude Altitude ) 2 700 127 556 831 687 613 area selected station information, (mi 2,790 2,060 2,430 1,602 Drainage 81°52'03" 80°04'54" 84°40'25" 84°54'04" 84°59'16" 84°46'42" 84°51'37" 84°55'42" 84°56'29" 84°29'47" 31°13'16" 30°21'13" 33°39'24" 33°28'37" 33°14'07" 34°36'03" 34°34'35" 34°40'00" 34°34'42" 34°14'23" stations, periodsanalyses, of lsius; ft, feet; —, no data] no —, feet; ft, lsius; Station nameStation Latitude Longitude Satilla River at Atkinson, Ga. Atkinson, at River Satilla Fla. nearSt Marys MacClenny, River Chattahoochee nearGa. Fairburn, River Ga.Chattahoochee near Whitesburg, River near Corinth, Ga. River New Ga. Nickelsville, near River Coosawattee Ga Chapel, Pine near River Coosawattee Ga. Tilton, at River Conasauga Ga. Resaca, at River Oostanaula at Canton, River Ga. Etowah Stream-temperature daily record Stream-temperature daily , square miles; ° C, degrees , Ce square miles; ° C, degrees 2 Station number 02228000 02231000 02337170 02338000 02338660 02382720 02383500 02387000 02387500 02392000 Table 2. [mi

45 96.6 96.5 98.3 98.5 98.5 Variance Variance (percent) .89 .92 .80 .75 .75 error error (° C) Standard 2.81 2.76 2.60 2.61 2.61 Phase (radians) coefficient coefficient 9.1 7.9 10.7 10.6 10.6 (° C) Amplitude Harmonic properties computed from observed data 17.9 13.8 19.5 17.7 18.5 (° C) Mean 1,910 1,925 2,906 2,905 2,906 mean minimum minimum maximum maximum Statistic Days of record Period Period 1971-76 1971-76 1975-85 1975-85 1975-85 analyzed 898 550 (ft) Altitude Altitude ) 2 60 area (mi 4,362 Drainage Drainage 84°23'18" 85°26'46" periodsselectedof analyses, station information, and harmonic properties—Continued 34°07'09" 34°11'54" Celsius; ft, feet; —, no data] Station nameStation Latitude Longitude Little River near Roswell, Ga. Roswell, near River Little at StateCoosa River Line, Ala.-Ga. Stream-temperature daily record stations, , square miles; ° C, degrees , square miles; ° C, degrees 2 Station number 02392500 02397530 Table 2. [mi

46 88.1 84.5 85.9 90.2 82.2 75.1 81.2 79.5 89.0 86.0 86.7 84.5 87.7 86.6 85.9 86.5 87.5 88.5 87.7 90.5 88.8 Variance Variance (percent)

2.22 2.0 2.0 2.43 2.43 2.35 2.54 2.82 2.29 2.23 2.23 2.24 2.18 2.24 2.25 2.22 1.93 2.01 2.38 2.19 2.26 error (° C) Standard 2.80 2.77 2.80 2.82 2.79 2.76 2.78 2.83 2.84 2.81 2.85 2.80 2.82 2.86 2.83 2.86 2.87 2.76 2.80 2.90 2.85 Phase Phase (radians) onic properties 9.2 7.2 8.2 9.6 9.5 7.6 8.2 8.6 9.3 8.9 9.2 9.1 9.3 9.3 8.4 7.7 9.9 9.4 9.6 10.0 10.0 (° C) Amplitude Harmonic properties computed from observed data observed from computed properties Harmonic (° C) 13.6 12.0 14.3 16.4 15.3 15.3 17.0 16.5 17.6 18.3 17.7 15.6 14.6 15.1 15.4 15.4 17.0 19.0 15.5 14.8 15.4 Mean of of 83 68 80 260 174 100 147 156 121 293 255 123 183 119 122 278 134 250 158 116 120 Number observations of record Period 09/57–12/84 07/64–08/84 08/62–07/75 10/56–10/79 10/54–06/74 11/58–07/76 10/54–09/83 07/54–06/79 08/74–12/84 05/37–10/84 09/54–12/84 08/70–12/84 08/56–11/84 07/74–12/84 05/72–12/84 07/64–01/85 04/54–01/74 06/54–12/84 08/56–10/77 07/74–12/84 07/74–12/84 is, selectedis, station information,and harm 96 60 20 80 87 695 357 354 330 174 540 806 660 560 368 279 556 580 530 (ft) 1,166 1,869 Altitude Altitude ) 2 57 61 55 72 207 291 473 646 555 465 134 236 291 108 398 270 783 area area (mi 1,430 2,370 2,650 5,180 Drainage SAVANNAH RIVER BASIN SAVANNAH ALTAMAHA RIVER BASIN ALTAMAHA 83°18'22" 83°31'50" 83°29'17" 82°46'12" 82°44'33" 82°28'06" 81°57'50" 81°39'05" 81°33'21" 81°24'58" 81°53'20" 83°57'29" 84°04'45" 83°58'43" 83°49'42" 83°43'25" 83°44'21" 82°40'26" 83°25'22" 83°22'56" 83°19'36" Longitude Latitude 34°48'50" 34°53'25" 34°30'15" 33°58'27" 33°36'46" 33°22'06" 33°07'05" 32°56'00" 32°29'40" 32°11'29" 32°11'05" 33°29'04" 33°51'11" 33°41'23" 33°26'58" 33°05'59" 32°27'20" 31°55'06" 33°56'48" 33°58'28" 33°51'21" for regression analyses,analys periods of for regression Station name Station Chattooga near Clayton, River Ga. near Clayton, River Ga. Tallulah Ga. at Homer, Hudson River near Bell, Ga. Broad River Ga. near Washington, Little River Brier Creek near Thomson, Ga. Ga. Waynesboro, near Creek Brier Ga. Millhaven, at Creek Brier Ga. at Oliver, Ogeechee River near Eden,Ogeechee Ga. River Ga. Claxton, near River Canoochee Ga. Shoals, Snapping at 81 Route State at River South near Snellville, River Ga. Yellow (Conyers Intake) River at Conyers, Ga. Yellow Factory Bridge Newton Ga.Road near Stewart, River Alcovy Ga. Juliette, near Creek Falling Ga. Perry, at Creek Indian Big Ga. at Lumber City, Ocmulgee River near Athens, Ga.Middle Oconee River (Athens Intake) North Oconeeat Athens, Ga. River Ga. Watkinsville, near Shoals Barnett at River Oconee Periodic stream-temperature stations used , square miles; ft, feet; ° C, degrees Celsius] degrees C, ° feet; ft, miles; square , 2 Station Station number 02177000 02178400 02191200 02192000 02193500 02197520 02197830 02198000 02202190 02202500 02203000 02204520 02206500 02207300 02209260 02212600 02214500 02215500 02217500 02217740 02218000 Table 3. [mi

47 85.6 92.1 87.5 89.1 84.0 92.7 85.9 91.2 81.9 88.2 90.3 88.2 87.7 84.2 84.7 89.2 89.4 81.4 99.7 Variance Variance (percent) 2.20 2.16 2.18 2.15 2.53 2.09 2.10 1.86 2.33 2.23 2.36 2.27 2.22 2.33 2.24 2.01 2.31 2.00 1.93 error (° C) Standard 2.78 2.69 2.78 2.92 2.78 2.75 2.82 2.71 2.95 2.82 2.77 2.83 2.78 2.78 2.75 2.77 2.77 2.81 2.77 Phase Phase (radians) onic properties—Continued 9.2 9.3 8.8 9.1 8.0 9.3 8.4 8.4 9.1 8.5 8.1 8.5 8.3 9.0 8.6 7.4 8.4 10.1 10.0 (° C) Amplitude Harmonic properties computed from observed data observed from computed properties Harmonic (° C) 16.0 18.0 19.3 18.0 18.5 19.4 18.4 19.7 17.9 18.9 20.0 19.9 18.6 19.6 18.5 18.9 18.4 17.7 13.9 Mean n information, and harm of of 64 93 149 126 146 212 215 182 166 103 163 258 258 171 164 115 231 110 123 Number observations of record Period 07/56–07/76 11/54–11/76 12/57–12/84 07/79–12/84 07/54–10/82 05/37–10/79 12/58–07/84 12/70–12/84 01/55–06/82 01/55–09/83 05/54–10/84 08/57–11/84 03/53–07/84 01/54–08/74 11/74–12/84 08/57–12/84 04/54–12/84 05/54–07/74 09/57–08/76 0.1 62 90 74 25 19 58 15 92 77 84 424 149 136 208 170 134 159 (ft) 1,220 analysis, selected statio Altitude Altitude ) 2 60 436 300 210 139 646 663 552 550 150 area area (mi 4,400 1,110 2,790 1,260 1,400 1,480 Drainage 11,600 13,600 14,000 83°20'58" 82°53'41" 82°21'13" 82°12'43" 82°10'39" 81°49'41" 81°50'18" 81°36'20" 82°27'50" 82°03'17" 81°52'03" 82°33'38" 83°11'33" 83°02'00" 83°20'23" 83°27'06" 84°02'44" 84°15'46" 83°38'09" CHATTAHOOCHEE RIVER BASIN CHATTAHOOCHEE SATILLA–ST. MARY’S RIVER BASINS MARY’S SATILLA–ST. ALTAMAHA RIVER BASIN—Continued RIVER ALTAMAHA SUWANNEE–OCHLOCKONEE RIVER BASINS SUWANNEE–OCHLOCKONEE 33°36'31" 32°32'40" 31°56'20" 32°09'36" 32°04'42" 31°39'16" 31°34'00" 31°25'37" 31°34'00" 31°27'04" 31°13'16" 82°40'50" 31°23'03" 30°42'14" 30°51'00" 30°47'22" 30°52'32" 30°51'54" 34°34'37" ions used for regression analyses, periods of regression ions used for Station name Latitude Longitude Apalachee River near Buckhead, Ga. Ga. Buckhead, near River Apalachee at Dublin, Ga. Oconee River Ga. near Baxley, Altamaha River Pendelton Creek at State Route Ohoopee,86 below Ga. Ga. Reidsville, near River Ohoopee Ga. at Doctortown, Altamaha River CreekPenholoway near Jesup, Ga. Ga. at Everett City, Altamaha River HurricaneCreek near Alma, Ga. Ga. Offerman, near River Satilla Little at Atkinson, Ga. Satilla River Ga. atSuwannee Fargo, River nearAlapaha Alapaha, River Ga. atAlapahaGa. Statenville, River Ga. at StateWithlacoochee River Route 94 near Valdosta, near Quitman,Ga. River Withlacoochee nearOchlockonee Thomasville, River Ga. Ga. Cairo, near Creek Tired Chattahoochee near Leaf, River Ga. Periodic stream-temperature stat , square miles; ft, feet; ° C, degrees Celsius] degrees C, ° feet; ft, miles; square , 2 Station Station number 02219500 02223500 02225000 02225470 02225500 02226000 02226100 02226160 02227000 02227500 02228000 02314500 02316000 02317500 02317757 02318500 02327500 02328000 02331000 Table 3. [mi

48 86.3 84.5 82.3 92.1 79.4 88.6 86.4 92.3 85.1 91.8 87.2 89.4 87.8 87.2 87.5 83.8 81.2 83.0 86.9 93.7 92.5 Variance Variance (percent) 2.18 2.33 2.23 2.17 2.80 2.31 2.31 1.96 2.04 2.06 2.25 2.20 2.48 1.65 2.16 2.17 2.52 1.96 2.22 2.07 1.90 error (° C) Standard 2.82 2.76 2.78 2.85 2.84 2.85 2.89 2.83 2.88 2.85 2.79 2.80 2.82 2.90 2.87 2.91 2.91 2.90 2.82 2.81 2.79 Phase Phase (radians) onic properties—Continued 8.7 7.9 7.8 9.4 8.9 9.3 9.0 9.1 6.8 9.8 9.8 6.2 9.0 7.3 8.0 7.2 7.6 8.1 7.5 10.0 10.2 (° C) Amplitude Harmonic properties computed from observed data observed from computed properties Harmonic (° C) 14.7 14.1 14.3 15.3 15.1 15.6 16.1 15.4 17.0 16.0 15.3 16.7 17.6 17.1 18.0 17.2 16.9 17.3 18.4 18.2 13.9 Mean n information, and harm of of 55 69 98 68 139 167 150 339 104 117 103 157 103 189 103 245 124 169 152 128 154 Number observations of record Period 02/68–11/84 10/56–09/76 05/60–09/76 05/57–12/84 07/74–05/79 08/56–09/70 07/74–12/84 08/56–06/74 08/62–11/73 08/56–07/76 09/64–07/76 07/56–06/74 04/54–06/79 04/54–11/73 05/54–12/84 07/54–06/82 05/54–07/84 10/54–11/73 04/54–07/84 08/57–07/78 06/57–08/75 86 961 857 940 601 580 550 286 711 729 605 335 366 256 386 338 213 150 (ft) 1,129 1,129 1,255 analysis, selected statio Altitude Altitude ) 2 72 70 75 62 70 93 45 315 153 246 182 272 101 186 197 188 620 485 134 area area (mi 1,850 2,900 Drainage FLINT RIVER BASIN COOSA RIVER BASIN 83°37'14" 83°56'23" 84°16'10" 84°36'53" 84°47'35" 85°03'40" 85°08'43" 85°04'08" 84°48'12" 84°25'45" 84°31'25" 84°21'45" 84°13'57" 84°15'58" 84°02'38" 83°54'03" 84°32'53" 84°40'43" 84°32'52" 84°44'18" 84°27'20" CHATTAHOOCHEE RIVER BASIN—Continued CHATTAHOOCHEE 34°32'27" 34°31'41" 34°03'02" 33°46'22" 33°37'20" 33°05'27" 32°54'37" 32°44'28" 31°56'03" 33°14'39" 33°19'10" 32°54'15" 32°43'17" 32°28'00" 32°17'53" 32°11'44" 32°03'09" 31°33'17" 31°22'58" 31°02'23" 34°40'53" ions used for regression analyses, periods of regression ions used for Station name Latitude Longitude Chattahoochee near Cornelia, River Ga. Chestatee at State River Route 52 near Dahlonega, Ga. Big Creek near Alpharetta, Ga. Sweetwater Creek near Austell, Ga. at StateDog River Ga. Route 166 near Fairplay, Creek near LaGrange, Ga. Yellowjacket Ga. Point, West near Creek Cane Long Mountain Oak Creek near Hamilton, Ga. Pataula Creek near Lumpkin, Ga. Ga. near Griffin, Flint River Ga. Senoia, near Creek Line Potato Creek near Thomaston, Ga. Ga. Culloden, near River Flint CreekWhitewater Rambulette below Creek Ga.near Butler, at Montezuma,Flint River Ga. Creek at Byromville, Ga. Turkey Kinchafoonee Creek at Preston, Ga. Pachitla Creek near Edison, Ga. Ichawaynochaway Creek at Milford, Ga. Spring Ga. Creek near Iron City, Ga. near Ellijay, Cartecay River Periodic stream-temperature stat , square miles; ft, feet; ° C, degrees Celsius] degrees C, ° feet; ft, miles; square , 2 Station Station number 02331600 02333500 02335700 02337000 02337438 02339000 02339720 02340500 02343200 02344500 02344700 02346500 02347500 02349000 02349500 02349900 02350600 02353400 02353500 02357000 02379500 Table 3. [mi

49 89.1 88.4 93.7 85.9 92.5 84.4 89.1 90.2 92.1 85.2 88.3 89.9 79.0 89.6 85.5 90.0 92.6 Variance Variance (percent) 2.04 1.88 1.48 2.30 1.96 2.27 2.12 1.90 1.97 1.83 2.33 2.09 2.13 2.04 2.21 2.03 1.76 error (° C) Standard 2.82 2.77 2.76 2.78 2.78 2.75 2.77 2.74 2.81 2.74 2.83 2.85 2.81 2.77 2.82 2.79 2.77 Phase Phase (radians) onic properties—Continued 8.0 8.0 9.6 9.4 9.9 9.0 9.8 8.2 8.9 7.2 9.4 9.1 6.5 8.1 7.9 9.0 8.5 (° C) Amplitude Harmonic properties computed from observed data observed from computed properties Harmonic (° C) 13.6 13.7 15.1 15.2 15.1 14.7 15.0 13.6 14.2 15.6 15.4 15.6 12.7 12.9 13.5 14.8 15.3 Mean n information, and harm of of 32 92 80 80 121 175 119 202 111 163 212 290 117 270 297 218 119 Number observations of record Period 06/57–07/74 05/63–08/83 07/65–12/72 06/57–12/72 07/74–12/84 07/60–06/83 09/57–12/72 09/56–08/84 06/57–10/84 07/57–12/84 07/74–11/84 07/74–12/84 08/51–06/82 01/51–06/84 01/51–06/74 08/74–11/84 08/74–12/84 651 616 650 689 604 845 613 920 919 680 679 (ft) 1,242 1,216 1,050 1,933 1,782 1,450 analysis, selected statio Altitude Altitude ) 2 88 64 46 71 236 521 831 308 103 613 192 272 245 177 198 148 area area (mi 1,602 Drainage TENNESSEE RIVER BASIN 84°28'40" 84°30'31" 84°41'44" 84°51'37" 84°52'30" 84°46'12" 84°56'29" 84°03'21" 84°29'47" 85°20'19" 85°20'11" 85°16'45" 83°43'01" 84°14'24" 84°23'12" 85°08'42" 85°12'20" COOSA RIVER BASIN—Continued 34°41'06" 34°40'18" 34°36'13" 34°34'35" 34°47'20" 34°43'00" 34°34'42" 34°22'57" 34°14'23" 34°28'03" 33°44'27" 33°29'34" 34°54'17" 34°47'24" 34°58'53" 34°58'39" 34°57'26" ions used for regression analyses, periods of regression ions used for Station name Latitude Longitude Ellijay River at Ellijay, Ga. Ga. Ellijay, at River Ellijay Ga. near Ellijay, River Coosawattee at Carters, Ga. River Coosawattee near CoosawatteePine River Chapel, Ga. Ga. Dalton, near Intake) (Dalton River Conasauga Holly Creek near Chatsworth, Ga. Oostanaula at Resaca, River Ga. Ga. near Dawsonville, River Etowah at Canton, River Ga. Etowah at Summerville, ChattoogaGa. River Ga. Tallapoosa, below River Tallapoosa Ga. Bowdon, below River Little Tallapoosa Ga. at Presley, River Hiwassee near Dial, Ga. River Toccoa Fightingtown Creek at McCaysville, Ga. South Chickamauga Creek at Graysville, Ga. Ga. Chickamauga Creek near Lakeview, West Periodic stream-temperature stat , square miles; ft, feet; ° C, degrees Celsius] degrees C, ° feet; ft, miles; square , 2 Station Station number 02380000 02380500 02382500 02383500 02384748 02385800 02387500 02389000 02392000 02398000 02411930 02413210 03545000 03558000 03560000 03566800 03567340 Table 3. [mi

50 GRAPHS SHOWING HARMONIC STREAM TEMPERATURE CURVES OF OBSERVED DATA AND STATEWIDE HARMONIC EQUATION FOR SELECTED STATIONS, FIGURES 14–211

51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150