ST. LAWRENCE RIVER BASIN
04285500 NORTH BRANCH WINOOSKI RIVER AT WRIGHTSVILLE, VT
LOCATION.--Lat 44°17'58", long 72°34'45", Washington County, Hydrologic Unit 02010003, on right bank, at Wrightsville,
0.8 mi downstream from Wrightsville Detention Reservoir, and 3.5 mi upstream from mouth.
DRAINAGE AREA.--69.2 mi².
PERIOD OF RECORD.--Discharge records: October 1933 to current year.
Water-quality records: Water year 1957.
REVISED RECORDS.--WSP 1237: 1937: 1934-39.
GAGE.--Water-stage recorder and concrete control. Datum of gage is 550.53 ft above sea level (levels by U.S. Army
Corps of Engineers). Prior to November 21, 1934, nonrecording gage at same site and datum.
REMARKS.--Records good except those for estimated daily discharges , which are fair. Discharge affected since 1935 by
Wrightsville Detention Reservoir (Reservoirs in Winooski River Basin). Flow regulated by powerplant at
Wrightsville Detention Reservoir since September 1985. Occasional diurnal fluctuation at low flow caused by small
mill upstream; more frequent diurnal fluctuation prior to 1968. Maximum discharge since construction of
Wrightsville Detention Reservoir in 1935, 1,100 ft³/s, July 5 and October 24, 1990, gage height 4.32 ft.
EXTREMES OUTSIDE PERIOD OF RECORD.--Maximum discharge since at least 1830, 17,200 ft³/s, November 3, 1927, by
computation of peak flow over dam 0.8 mi upstream.
EXTREMES FOR CURRENT YEAR.--Maximum discharge, 975 ft³/s, December 2, gage height, 3.50 ft; minimum daily discharge,
9.2 ft³/s, July 1 .
DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997
DAILY MEAN VALUE
DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
1 28 83 73 e76 e50 205 466 386 106 9.2 14 90
2 22 65 804 90 e40 194 311 527 133 17 12 60
3 50 66 944 95 e48 351 267 346 80 129 23 90
4 38 58 898 98 e55 261 255 415 80 341 26 78
5 28 58 719 92 e50 203 331 311 31 171 25 84
6 27 65 245 178 e46 146 745 268 38 53 28 38
7 27 62 155 154 e47 133 917 668 46 29 21 39
8 28 87 132 e103 e52 e113 932 354 36 29 14 61
9 29 454 115 e52 e60 e103 889 247 29 129 23 43
10 29 757 101 123 e51 89 685 265 27 227 25 35
11 102 321 99 90 e47 e90 264 323 27 118 35 35
12 58 212 86 77 e42 e86 212 262 30 39 47 49
13 50 111 89 e69 e48 e80 202 245 35 29 296 44
14 39 132 79 71 e63 e82 202 212 28 41 789 37
15 38 66 110 64 e46 e74 203 191 22 599 820 38
16 35 73 105 e67 e48 e68 221 180 19 869 300 26
17 27 84 121 e64 e43 e60 407 201 18 738 180 34
18 27 80 251 e64 e42 e63 612 202 23 295 125 26
19 27 82 316 e64 49 e62 660 196 125 160 78 26
20 28 86 247 e65 91 e59 634 198 108 99 41 34
21 499 80 153 e67 110 e58 582 178 37 41 81 34
22 819 71 137 e66 305 e65 534 154 103 72 307 34
23 625 67 130 e62 758 e58 513 152 132 35 381 34
24 312 60 142 e64 393 e60 496 118 63 29 252 38
25 218 58 476 e62 224 e62 405 115 37 24 176 38
26 134 59 286 e63 146 64 365 109 36 21 95 34
27 92 59 212 e62 168 94 368 89 30 23 91 27
28 87 48 151 e59 218 119 472 78 20 28 489 27
29 75 32 144 e55 --- 187 555 84 15 25 278 76
30 59 44 208 e56 --- 408 382 51 11 21 178 172
31 82 --- 121 e54 --- 487 --- 90 --- 16 107 ---
TOTAL 3739 3580 7849 2426 3340 4184 14087 7215 1525 4456.2 5357 1481
MEAN 121 119 253 78.3 119 135 470 233 50.8 144 173 49.4
MAX 819 757 944 178 758 487 932 668 133 869 820 172
MIN 22 32 73 52 40 58 202 51 11 9.2 12 26
MEAN(|) 122 119 253 77.5 123 139 468 227 50.3 144 174 49.3
CFSM(|) 1.76 1.72 3.66 1.12 1.78 2.01 6.76 3.28 0.73 2.08 2.51 0.71
IN(|) 2.03 1.92 4.22 1.30 1.85 2.31 7.55 3.79 0.81 2.39 2.90 0.79
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1934 - 1997, BY WATER YEAR (WY)
MEAN 107 139 114 81.8 69.9 172 455 249 89.4 48.9 48.8 51.9
MAX 437 249 318 243 348 556 714 617 396 271 278 230
(WY) 1991 1984 1974 1996 1981 1936 1994 1972 1984 1973 1995 1938
MIN 6.00 25.9 28.0 17.5 14.6 21.4 121 47.3 15.8 7.91 8.47 5.10
(WY) 1964 1954 1948 1940 1980 1940 1995 1941 1949 1953 1942 1963
SUMMARY STATISTICS FOR 1996 CALENDAR YEAR FOR 1997 WATER YEAR WATER YEARS 1934 - 1997
ANNUAL TOTAL 67461.9 59239.2
ANNUAL MEAN 184 162 135
HIGHEST ANNUAL MEAN 226 1973
LOWEST ANNUAL MEAN 71.4 1965
HIGHEST DAILY MEAN 1030 Apr 24 944 Dec 3 1620 Apr 17 1934
LOWEST DAILY MEAN 1.5 Jun 2 9.2 Jul 1 .20 Aug 13 1941
ANNUAL SEVEN-DAY MINIMUM 8.5 Sep 2 20 Jul 29 2.8 Aug 14 1970
INSTANTANEOUS PEAK FLOW 975 Dec 2 a 2170 Apr 12 1934
INSTANTANEOUS PEAK STAGE 3.50 Dec 2 6.53 Apr 12 1934
10 PERCENT EXCEEDS 555 411 401
50 PERCENT EXCEEDS 88 82 60
90 PERCENT EXCEEDS 24 27 14
a From rating curve extended above 920 ft³/s.
e Estimated.
(|) Adjusted for change in contents in Wrightsville Detention Reservoir.
NOTE: All statistics are based on unadjusted daily and monthly mean data.
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