MERRIMACK RIVER BASIN
01092000 MERRIMACK RIVER NEAR GOFFS FALLS, BELOW MANCHESTER, NH
LOCATION.--Lat 42°56'54", long 71°27'52", Hillsborough County, Hydrologic Unit 01070002, on right bank, 600 ft upstream
from bridge on Interstate Highway 293, 0.8 mi downstream from Bowman Brook, 1.3 mi north of Goffs Falls, and 2.3 mi
downstream from Piscataquog River.
DRAINAGE AREA.--3,092 mi².
PERIOD OF RECORD.--Discharge records: October 1936 to current year. October 1936 monthly discharge only,
published in WSP 1301.
Water-quality records: Water years 1952-53, 1957, 1971.
REVISED RECORDS.--WSP 1231: 1937. WSP 1271: 1937(M, m).
GAGE.--Water-stage recorder. Datum of gage is 109.27 ft above sea level.
REMARKS.--Records good except for estimated daily discharges, which are fair. Flow regulated by powerplants, by
Franklin Falls Reservoir since 1942, and by Squam, Newfound, Winnipesaukee, Winnisquam, and other lakes and
reservoirs upstream (Reservoirs in Merrimack River basin).
EXTREMES OUTSIDE PERIOD OF RECORD.--Maximum discharge since at least 1722, 150,000 ft³/s, March 20, 1936, gage height,
35.19 ft, from floodmarks, from rating curve extended above 48,000 ft³/s on basis of computation of flow over dam
at gage heights 25.87 ft and 35.19 ft.
EXTREMES FOR CURRENT YEAR.--Maximum discharge, 33,900 ft³/s, October 22, gage height, 11.46 ft; minimum daily
discharge, 889 ft³/s, August 8.
DISCHARGE, CUBIC FEET PER SECOND, WATER YEAR OCTOBER 1996 TO SEPTEMBER 1997
DAILY MEAN VALUES
DAY OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
1 1740 8080 6130 10600 4390 10300 16800 15700 4480 1420 1770 2020
2 1740 7610 9640 9610 4730 10900 15100 14500 5240 1240 1410 1920
3 1560 6740 23800 9230 4960 10300 14100 15300 5360 1310 1380 1890
4 1550 5680 26500 9300 4340 9670 14500 14700 4960 2740 1570 1770
5 1380 4860 20900 9140 4510 9420 15000 13900 4610 4090 1650 1620
6 1340 4640 15600 9300 4990 9670 16200 11900 4160 3250 1100 1560
7 1580 4760 12700 9200 e5000 9840 18300 11600 3820 1780 909 1750
8 1430 4960 11500 8250 e4800 8840 21400 11900 3420 1820 889 1130
9 2510 5800 10900 7810 e4500 7260 22600 11900 3160 2120 1290 1360
10 2100 12700 10200 7530 e4400 7340 19300 12300 3240 2770 1060 1460
11 1980 19100 9230 7320 e4400 7120 15300 10200 3090 4100 1250 1800
12 1930 15800 8520 6500 4400 6660 12700 9400 2770 3550 1450 2080
13 2080 12000 8940 6150 4050 6260 12400 9140 2950 2600 1260 1650
14 1800 10300 9480 5960 3690 5820 12800 8680 2860 2180 1360 2160
15 1660 9080 9590 5680 3800 5300 12800 8170 2880 3300 1200 1480
16 1460 6260 9730 5610 4430 5780 12300 7960 2270 5800 1280 1400
17 1520 5950 10600 5730 4040 5710 11800 8640 2220 7200 1570 1490
18 1510 5870 14600 6190 3900 5460 14900 8660 2380 4440 1330 1470
19 1420 5110 17500 6280 4150 5050 23300 8250 1790 3410 1200 1560
20 3560 5420 19100 5510 4610 5170 31900 8820 3160 4450 1080 1250
21 15900 5270 17500 5290 5280 5060 26900 9300 3910 4160 1050 1130
22 31900 5210 14600 5200 7430 5300 28400 9180 2640 3310 1520 1200
23 28600 5290 12400 5650 10500 5180 25800 7880 2470 3080 1880 1450
24 25500 4970 11200 5200 11300 4940 22500 7050 2320 2660 2140 1230
25 21400 4400 13600 5250 10900 4940 20600 6770 2160 2690 1720 1170
26 17700 5310 18600 5480 9300 5790 18700 6410 2000 2110 1450 1030
27 15600 6940 17100 5390 8260 8290 15500 5560 1930 2340 1090 1010
28 14000 7690 14400 5360 9060 9410 14700 5330 1270 2450 1670 1040
29 13600 6090 12700 5010 --- 10300 17400 5330 1120 2300 2310 1410
30 11300 5710 12700 4840 --- 12400 17800 4420 1270 1660 3170 922
31 8900 --- 12800 5210 --- 15800 --- 4370 --- 1740 2820 ---
TOTAL 240250 217600 422760 208780 160120 239280 541800 293220 89910 92070 46828 44412
MEAN 7750 7253 13640 6735 5719 7719 18060 9459 2997 2970 1511 1480
MAX 31900 19100 26500 10600 11300 15800 31900 15700 5360 7200 3170 2160
MIN 1340 4400 6130 4840 3690 4940 11800 4370 1120 1240 889 922
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1937 - 1997, BY WATER YEAR (WY)
MEAN 3049 4731 5360 4533 4746 7866 14060 8790 4385 2430 1976 2066
MAX 10380 12910 13690 10840 11370 18240 25660 18250 16480 11470 8576 14500
(WY) 1978 1996 1984 1978 1970 1953 1969 1954 1984 1973 1990 1938
MIN 771 1341 1458 1410 1354 2141 4612 3059 1354 808 782 745
(WY) 1965 1979 1979 1948 1980 1940 1995 1957 1964 1991 1965 1957
SUMMARY STATISTICS FOR 1996 CALENDAR YEAR FOR 1997 WATER YEAR WATER YEARS 1937 - 1997
ANNUAL TOTAL 3202095 2597030
ANNUAL MEAN 8749 7115 5303
HIGHEST ANNUAL MEAN 8400 1984
LOWEST ANNUAL MEAN 2248 1965
HIGHEST DAILY MEAN 34100 Apr 17 31900 Oct 22 94800 Sep 23 1938
LOWEST DAILY MEAN 870 Sep 13 889 Aug 8 98 Oct 11 1964
ANNUAL SEVEN-DAY MINIMUM 931 Sep 9 1120 Sep 24 394 Sep 25 1964
INSTANTANEOUS PEAK FLOW 33900 Oct 22 a 102000 Sep 23 1938
INSTANTANEOUS PEAK STAGE 11.46 Oct 22 25.87 Sep 23 1938
10 PERCENT EXCEEDS 20900 15500 12200
50 PERCENT EXCEEDS 6210 5280 3410
90 PERCENT EXCEEDS 1310 1410 1200
a From rating curve extended above 48,000 ft³/s as explained above.
e Estimated.
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