THAMES RIVER BASIN 01119500 WILLIMANTIC RIVER NEAR COVENTRY, CT LOCATION.--Lat 4145'02", long 7215'58", Tolland County, Hydrologic Unit 01100002, on left bank 700 ft upstream from bridge on State Highway 31, 1 mi downstream from Mill Brook, 2.4 mi southeast of South Coventry, 2.8 mi upstream from Hop River, and 6.3 mi upstream from mouth. DRAINAGE AREA.--l21 mi2. PERIOD OF RECORD.--Discharge: September 1931 to current year. Water-quality records: Water years 1956-57, 1963-64, 1975-80. REVISED RECORDS.--WSP 781: 1934 (m). WSP 851: 1935-36. WSP 1201: 1932 (M,m), l933-34, l937, 1939-42. WDR 79-1: 1978 (m). WDR CT-83-1: Drainage area. GAGE.--Water-stage recorder. Datum of gage is 239.05 ft above sea level (levels by Corps of Engineers). REMARKS.--Records good except for periods of estimated record, which are fair. Natural flow of stream regulated by Staffordville Reservoir. High streamflow regulated by six flood-detention reservoirs in Middle River basin, combined usable flood capacity, 305,400,000 ft3. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1997 TO SEPTEMBER 1998 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 51 84 210 e165 259 375 329 212 314 1380 84 40 2 47 323 215 e142 244 352 606 311 242 697 65 30 3 45 239 167 153 239 319 593 313 340 435 55 27 4 50 147 149 189 241 290 468 267 249 319 47 25 5 56 100 150 270 255 271 394 249 174 263 43 22 6 57 78 141 284 243 258 353 607 136 216 41 19 7 36 73 129 325 224 233 317 788 128 183 38 24 8 23 67 116 575 208 225 289 565 117 174 35 40 9 20 248 107 669 195 1740 293 486 123 200 33 40 10 21 379 103 572 186 3210 701 816 115 177 32 37 11 18 227 e105 425 186 1430 534 992 96 146 32 35 12 16 148 e100 334 496 912 410 779 99 123 28 33 13 15 109 e91 e270 554 686 355 558 301 111 26 31 14 16 108 e85 e240 401 592 327 468 739 100 28 28 15 17 122 e82 e228 e255 543 300 389 598 91 26 19 16 17 120 e80 348 e230 487 287 346 427 86 26 29 17 17 106 e77 306 e216 449 331 326 323 79 36 36 18 18 94 e75 260 606 432 384 319 298 74 52 28 19 18 85 e73 e220 591 875 319 279 616 67 69 23 20 19 80 e71 e205 449 1110 491 243 422 69 50 21 21 19 78 e68 e188 380 775 444 216 378 77 38 19 22 23 186 e66 185 325 632 368 192 289 78 32 75 23 22 273 e65 186 293 547 325 176 231 149 28 95 24 19 212 e64 1170 398 518 358 162 214 398 28 56 25 31 161 142 953 571 508 330 155 187 198 32 38 26 43 132 196 569 486 498 303 157 152 124 71 32 27 54 162 e170 412 390 523 312 136 173 93 78 35 28 65 164 e130 351 338 502 268 121 177 77 55 38 29 46 142 e113 313 --- 443 242 113 148 72 38 32 30 48 130 326 295 --- 394 223 182 822 65 31 42 31 33 --- 296 277 --- 358 --- 157 --- 71 36 --- TOTAL 980 4577 3962 11079 9459 20487 11254 11080 8628 6392 1313 1049 MEAN 31.6 153 128 357 338 661 375 357 288 206 42.4 35.0 MAX 65 379 326 1170 606 3210 701 992 822 1380 84 95 MIN 15 67 64 142 186 225 223 113 96 65 26 19 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1932 - 1998, BY WATER YEAR (WY) MEAN 116 189 243 268 268 413 403 262 180 92.7 90.9 98.0 MAX 606 631 761 929 619 1050 897 596 869 421 972 1176 (WY) 1956 1956 1997 1979 1970 1936 1940 1989 1982 1938 1955 1938 MIN 15.5 29.0 61.9 35.6 86.3 195 145 108 41.6 22.2 16.9 14.5 (WY) 1958 1932 1932 1981 1980 1989 1985 1957 1957 1957 1957 1957 e Estimated. SUMMARY STATISTICS FOR 1997 CALENDAR YEAR FOR 1998 WATER YEAR WATER YEARS 1932 - 1998 ANNUAL TOTAL 62960 90260 ANNUAL MEAN 172 247 218 HIGHEST ANNUAL MEAN 370 1938 LOWEST ANNUAL MEAN 97.9 1965 HIGHEST DAILY MEAN 716 Apr 5 3210 Mar 10 12900 Sep 21 1938 LOWEST DAILY MEAN 15 Oct 13 15 Oct 13 2.5 Sep 18 1949 ANNUAL SEVEN-DAY MINIMUM 17 Oct 11 17 Oct 11 9.5 Sep 6 1995 INSTANTANEOUS PEAK FLOW 3940 Mar 10 a24200 Aug 19 1955 INSTANTANEOUS PEAK STAGE 10.06 Mar 10 b18.66 Aug 19 1955 INSTANTANEOUS LOW FLOW 13 Oct 14 2.0 Aug 21 1949 10 PERCENT EXCEEDS 356 550 450 50 PERCENT EXCEEDS 116 177 150 90 PERCENT EXCEEDS 26 30 35 a From rating curve extended above 3,600 ft3/s on basis of computation of flow over dam at gage height 12.2 feet, and contracted opening measurement of peak flow. b From floodmarks.