PAWCATUCK RIVER BASIN 01118500 PAWCATUCK RIVER AT WESTERLY, RI LOCATION.--Lat 41××23'01", long 71××50'01", Washington County, Hydrologic Unit 01090005, on left bank at Westerly, 2.1 mi downstream from Shunock River. DRAINAGE AREA.--295 mi2. WATER-DISCHARGE RECORDS PERIOD OF RECORD.--November 1940 to current year. REVISED RECORDS.--WSP 1051: Drainage area. GAGE.--Water-stage recorder. Datum of gage is 1.76 ft below sea level. REMARKS.--Records good; many days are adjusted for tidal backwater which lasts as much as 4 hours during times of high tide. Diurnal fluctuation at low flow prior to 1962 by mills upstream; regulation much greater prior to 1958. Diversion upstream for municipal supply of Westerly. EXTREMES FOR PERIOD OF RECORD.--Maximum discharge, 7,070 ft3/s, June 6, 1982, gage height, 12.86 ft; minimum daily, 25 ft3/s, Aug.17, 1941. EXTREMES OUTSIDE PERIOD OF RECORD.--Flood in March 1936 reached a discharge of 3,150 ft3/s, by computation of flow over dam 1.5 mi upstream. Maximum discharge since 1886 occurred in November 1927 and was possibly more than twice that in March 1936. Maximum stage since at least 1635, 15.0 ft Sept. 21, 1938, due to hurricane tidal wave. DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1998 TO SEPTEMBER 1999 DAILY MEAN VALUES DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP 1 161 168 258 261 776 1570 817 371 435 146 74 58 2 147 161 224 256 813 1880 775 361 396 147 70 50 3 138 161 226 313 2040 1890 726 356 367 149 66 44 4 135 168 225 664 2430 1760 690 382 336 145 62 44 5 131 168 219 750 2490 1550 663 436 311 150 58 44 6 134 168 197 606 2280 1400 635 520 291 155 56 47 7 126 171 190 515 1960 1480 605 540 277 139 52 50 8 126 164 197 458 1710 1450 588 496 261 129 72 74 9 144 161 194 579 1470 1310 573 471 242 120 91 93 10 289 158 191 860 1280 1180 571 449 225 120 91 144 11 419 179 186 799 1150 1070 547 407 213 114 81 485 12 457 280 186 652 1060 989 539 369 205 114 86 586 13 375 307 190 588 1010 935 545 344 213 114 76 448 14 288 270 175 537 963 896 515 333 229 125 76 269 15 279 245 168 689 911 890 495 307 234 120 84 190 16 273 224 167 1340 851 945 475 302 218 110 81 376 17 245 214 171 1340 791 995 541 290 208 100 78 670 18 218 271 171 1220 777 1070 565 273 205 97 75 730 19 200 286 172 1330 952 1050 548 272 195 94 68 617 20 187 267 174 1320 1010 994 515 361 188 98 63 455 21 176 260 176 1200 946 936 490 465 182 94 61 331 22 166 254 171 1090 857 933 471 425 179 93 63 269 23 167 239 171 966 768 980 472 401 172 91 64 221 24 169 222 172 1030 689 982 541 874 165 91 58 196 25 164 215 168 1590 672 1040 555 1180 159 91 54 182 26 159 229 161 1640 658 1030 517 1140 157 86 54 168 27 154 317 160 1470 659 964 479 968 153 86 68 173 28 152 348 161 1300 722 946 450 792 155 86 99 166 29 176 308 190 1120 --- 948 430 648 151 81 98 154 30 187 264 264 996 --- 926 409 550 147 81 79 161 31 182 --- 300 879 --- 873 --- 492 --- 79 70 --- TOTAL 6324 6847 5975 28358 32695 35862 16742 15575 6869 3445 2228 7495 MEAN 204 228 193 915 1168 1157 558 502 229 111 71.9 250 MAX 457 348 300 1640 2490 1890 817 1180 435 155 99 730 MIN 126 158 160 256 658 873 409 272 147 79 52 44 CFSM .69 .77 .65 3.10 3.96 3.92 1.89 1.70 .78 .38 .24 .85 IN. .80 .86 .75 3.58 4.12 4.52 2.11 1.96 .87 .43 .28 .95 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1941 - 1999, BY WATER YEAR (WY) MEAN 259 451 660 761 826 1046 981 715 495 264 232 218 MAX 1186 1450 1789 2151 1377 1775 2603 1274 2246 642 763 1233 (WY) 1956 1956 1987 1979 1982 1994 1983 1948 1982 1959 1946 1954 MIN 87.2 93.2 115 131 325 495 371 325 210 98.5 71.9 65.7 (WY) 1950 1966 1966 1981 1980 1981 1966 1986 1942 1957 1999 1964 PAWCATUCK RIVER BASIN 01118500 PAWCATUCK RIVER AT WESTERLY, RI—Continued SUMMARY STATISTICS FOR 1998 CALENDAR YEAR FOR 1999 WATER YEAR WATER YEARS 1941 - 1999 ANNUAL TOTAL 275672 168415 ANNUAL MEAN 755 461 577 HIGHEST ANNUAL MEAN 871 1973 LOWEST ANNUAL MEAN 251 1981 HIGHEST DAILY MEAN 2740 Mar 11 2490 Feb 5 6220 Jun 6 1982 LOWEST DAILY MEAN 114 Sep 21 44 Sep 3 25 Aug 17 1941 ANNUAL SEVEN-DAY MINIMUM 123 Sep 15 48 Sep 1 47 Sep 2 1995 INSTANTANEOUS PEAK FLOW 2540 Feb 5 7070 Jun 6 1982 INSTANTANEOUS PEAK STAGE 7.44 Feb 5 12.86 Jun 6 1982 INSTANTANEOUS LOW FLOW 44 Sep 3 ANNUAL RUNOFF (CFSM) 2.56 1.56 1.96 ANNUAL RUNOFF (INCHES) 34.76 21.24 26.58 10 PERCENT EXCEEDS 1720 1050 1200 50 PERCENT EXCEEDS 494 269 450 90 PERCENT EXCEEDS 161 83 127