NORWALK RIVER BASIN 01209700 NORWALK RIVER AT SOUTH WILTON, CT LOCATION.--Lat 4109'49", long 7325'11", Fairfield County, Hydrologic Unit 01100006, on right bank at upstream side of bridge on Kent Road at South Wilton, 2.5 mi north of Norwalk. DRAINAGE AREA.--30.0 mi2. PERIOD OF RECORD.--Discharge: Occasional low-flow measurements, water years 1961-62. September 1962 to current year. Water-quality records: Water years 1976-78. REVISED RECORDS.--WDR CT-80-1: 1968-70 (P), 1971-79 (M,P). GAGE.--Water-stage recorder. Datum of gage is 115.69 ft above sea level. REMARKS.--Records good except for periods of estimated record, which are fair. Occasional regulation at low flow by mill upstream. City of Norwalk diverts an indeterminable amount of water from Streets (Popes) Pond, drainage area 2.36 mi2. High flows affected by Spectacle Swamp Detention Reservoir, drainage area, 1.16 mi2. EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of October 1955 reached a stage of 13.5 ft from floodmarks. 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 5.2 42 28 68 e74 e118 e90 e54 112 46 5.6 3.8 2 5.3 84 25 64 e71 e102 e148 145 68 27 5.3 4.2 3 4.8 53 22 59 e71 e92 e125 100 90 20 4.9 5.3 4 4.5 40 24 56 e70 e82 e103 84 50 15 4.6 4.6 5 4.3 32 27 55 e100 e75 e94 79 36 17 4.4 4.6 6 4.0 25 29 52 e95 e70 e88 99 28 16 4.3 4.1 7 4.1 18 25 72 e82 e67 e76 139 23 14 4.1 5.3 8 4.3 70 23 134 e73 e85 e67 105 20 13 3.7 6.4 9 4.0 121 22 92 e65 e250 e75 160 19 13 3.5 5.2 10 3.8 98 21 76 e58 e420 e240 311 20 12 3.5 5.2 11 4.0 59 23 66 e58 e290 e165 392 20 10 4.3 4.4 12 4.0 47 24 62 e162 e210 e120 286 56 8.8 8.7 3.9 13 4.1 38 24 57 e125 e168 e95 201 131 8.0 7.9 3.6 14 4.2 45 22 50 e95 e142 e85 163 96 7.3 7.0 3.4 15 4.6 43 20 46 e80 e130 e79 136 70 6.9 5.4 3.2 16 5.2 37 20 103 e74 e120 e75 115 64 6.6 4.8 3.1 17 5.3 33 20 69 e95 e114 e82 104 46 6.5 6.2 2.7 18 5.1 29 20 60 e240 e140 e81 94 46 6.2 6.4 2.6 19 5.5 27 20 57 e205 e258 e77 79 35 5.8 5.3 2.6 20 5.7 25 21 52 e175 e235 e132 67 28 5.7 4.5 2.5 21 5.4 22 21 45 e135 e202 e102 72 23 6.0 4.3 2.4 22 5.1 55 19 41 e113 e180 e92 59 20 5.6 3.7 3.9 23 5.4 43 51 104 e100 e160 e84 48 20 15 3.4 4.9 24 5.9 35 45 370 e150 e142 e81 41 19 31 3.5 5.0 25 13 33 107 186 e195 e128 e72 50 18 20 3.4 4.2 26 12 31 87 135 e170 e118 e73 63 16 16 13 3.7 27 25 32 65 114 e142 e108 e86 46 15 12 15 6.6 28 16 28 63 112 e123 e100 e70 42 13 9.1 11 6.6 29 13 26 65 e98 --- e94 e61 42 12 7.3 7.6 3.8 30 11 24 177 e87 --- e87 e56 55 31 6.0 5.9 4.0 31 9.7 --- 99 e80 --- e82 --- 44 --- 6.8 4.6 --- TOTAL 213.5 1295 1259 2722 3196 4569 2874 3475 1245 399.6 179.8 125.8 MEAN 6.89 43.2 40.6 87.8 114 147 95.8 112 41.5 12.9 5.80 4.19 MAX 25 121 177 370 240 420 240 392 131 46 15 6.6 MIN 3.8 18 19 41 58 67 56 41 12 5.6 3.4 2.4 CFSM .23 1.44 1.35 2.93 3.80 4.91 3.19 3.74 1.38 .43 .19 .14 IN. .26 1.61 1.56 3.38 3.96 5.67 3.56 4.31 1.54 .50 .22 .16 STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1962 - 1998, BY WATER YEAR (WY) MEAN 29.1 50.7 73.5 73.8 74.4 108 105 74.0 43.4 21.3 17.6 20.1 MAX 128 131 210 250 165 227 327 384 267 105 63.4 129 (WY) 1976 1973 1997 1979 1973 1983 1983 1989 1972 1984 1976 1971 MIN 2.02 4.23 13.2 5.90 18.1 43.7 25.4 15.9 10.4 3.73 1.64 1.64 (WY) 1965 1965 1981 1981 1980 1982 1985 1986 1965 1966 1965 1964 e Estimated. SUMMARY STATISTICS FOR 1997 CALENDAR YEAR FOR 1998 WATER YEAR WATER YEARS 1962 - 1998 ANNUAL TOTAL 19192.5 21553.7 ANNUAL MEAN 52.6 59.1 57.5 HIGHEST ANNUAL MEAN 94.6 1984 LOWEST ANNUAL MEAN 22.9 1966 HIGHEST DAILY MEAN 472 Jan 25 420 Mar 10 1650 Apr 10 1980 LOWEST DAILY MEAN 3.7 Sep 25 2.4 Sep 21 .80 Sep 12 1964 ANNUAL SEVEN-DAY MINIMUM 3.9 Sep 22 2.7 Sep 15 .91 Sep 7 1964 INSTANTANEOUS PEAK FLOW 523 Jan 24 2890 Apr 10 1980 INSTANTANEOUS PEAK STAGE 3.07 Jan 24 6.27 Apr 10 1980 INSTANTANEOUS LOW FLOW a2.3 Sep 21 .30 Sep 24 1964 ANNUAL RUNOFF (CFSM) 1.75 1.97 1.92 ANNUAL RUNOFF (INCHES) 23.80 26.73 26.05 10 PERCENT EXCEEDS 120 135 127 50 PERCENT EXCEEDS 34 41 33 90 PERCENT EXCEEDS 5.3 4.3 5.3 a Also occurred on Sept.22.