Water-Data Report 2012 01100000 MERRIMACK RIVER BELOW CONCORD RIVER AT LOWELL, MA MERRIMACK RIVER BASIN

LOCATION.--Lat 42°38′45″, long 71°17′56″ referenced to North American Datum of 1927, Middlesex County, MA, Hydrologic Unit 01070002, on right bank, 400 ft downstream from Rt 38, and 1,100 ft downstream from Concord River at Lowell. DRAINAGE AREA.--4,635 mi² of which 214 mi² probably is noncontributing.

SURFACE-WATER RECORDS PERIOD OF RECORD.--Discharge: June 1923 to current year. Water-quality records: water years 1954, 1966-74, 1999-2004. GAGE.--Water-stage recorder with satellite telemeter. Datum of gage is 5.18 ft above National Geodetic Vertical Datum of 1929. Prior to Mar. 7, 1934, at Boott Mills, 1,800 ft upstream and 700 ft above mouth of Concord River, in same gage pool and at same datum; gage-height record (provided by Proprietors of the Locks and Canals on Merrimack River) was indicative of flow including that of Concord River. COOPERATION.--Massachusetts Department of Conservation and Recreation, Office of Water Resources; and Massachusetts Department of Environmental Protection, Office of Watershed Management. REMARKS.--Records good except those for estimated daily discharge, which are fair. Daily discharge includes water released from 214 mi² in basins of Sudbury and Nashua Rivers and Lake Cochituate. Flow regulated by powerplants, by Franklin Falls Reservoir since 1942, and by Squam, Newfound, Winnipesaukee, Winnisquam, and other lakes and reservoirs upstream.

U.S. Department of the Interior Suggested citation: U.S. Geological Survey, 2013, Water-resources data for the United States, Water U.S. Geological Survey Year 2012: U.S. Geological Survey Water-Data Report WDR-US-2012, site 01100000, accessed at http://wdr.water.usgs.gov/wy2012/pdfs/01100000.2012.pdf Water-Data Report 2012 01100000 MERRIMACK RIVER BELOW CONCORD RIVER AT LOWELL, MA—Continued

DISCHARGE, CUBIC FEET PER SECOND WATER YEAR OCTOBER 2011 TO SEPTEMBER 2012 DAILY MEAN VALUES Day Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep

1 18,700 14,700 23,500 13,900 11,400 6,330 5,760 7,690 11,800 3,350 1,910 1,210 2 19,900 14,600 25,300 13,400 10,300 6,150 5,750 8,400 10,700 3,240 1,390 1,270 3 21,100 14,900 21,200 13,700 9,750 6,480 5,210 9,880 15,700 2,680 1,540 1,280 4 24,300 15,400 17,800 13,000 9,270 7,300 5,680 9,940 25,200 2,790 1,620 1,340 5 28,900 15,300 15,600 10,800 8,460 7,730 4,210 9,540 25,200 2,730 1,670 2,740 6 25,400 14,700 14,200 10,500 7,680 7,080 4,510 9,600 21,800 2,970 1,800 1,880 7 20,700 13,500 14,100 10,000 7,840 6,600 4,280 8,790 18,300 3,260 1,580 1,890 8 17,200 12,500 21,800 9,610 7,510 7,100 4,150 8,080 15,600 2,670 1,660 1,860 9 14,500 11,900 33,200 9,060 7,090 9,310 4,090 9,700 13,700 2,420 1,270 1,910 10 12,500 11,700 31,700 8,740 6,880 12,600 4,050 15,800 11,900 2,050 1,590 2,090 11 11,200 14,200 26,900 8,170 6,510 12,900 3,950 19,700 10,100 1,880 5,400 2,230 12 10,100 17,300 22,800 7,750 6,090 11,200 3,950 18,900 8,830 1,580 6,520 1,680 13 8,820 15,800 20,100 7,720 5,340 10,300 3,970 16,200 8,930 1,370 7,140 1,500 14 9,240 14,400 18,100 8,400 4,950 11,100 3,750 13,300 10,100 1,570 5,750 1,460 15 12,200 13,300 16,400 7,480 3,810 13,400 3,650 11,800 12,300 1,590 4,180 1,530 16 17,500 12,300 15,700 6,190 5,360 13,700 3,360 12,500 10,600 1,670 4,500 1,300 17 18,100 11,400 15,400 6,930 5,480 12,700 3,440 16,000 8,290 1,710 4,360 1,200 18 15,200 11,500 14,800 7,000 5,660 12,100 3,440 17,000 8,150 1,480 3,750 1,320 19 13,200 11,100 13,600 7,440 5,730 12,200 3,530 14,800 6,820 1,530 3,360 2,250 20 13,800 10,500 12,200 7,150 5,560 13,400 3,200 12,300 5,930 1,400 2,870 6,470 21 15,700 10,100 11,900 6,560 5,180 14,000 2,980 10,200 5,580 1,360 2,440 6,420 22 16,100 9,630 11,800 6,060 5,000 13,800 3,250 8,470 4,010 1,280 2,390 3,400 23 15,000 10,200 12,900 6,110 5,050 13,000 7,880 8,410 4,170 1,240 1,890 2,830 24 13,700 13,600 14,900 6,570 5,270 12,000 16,200 7,950 3,650 1,340 1,760 2,590 25 12,400 14,200 14,800 7,460 7,280 10,800 18,900 7,470 4,110 1,300 1,630 2,430 26 11,400 13,100 13,200 8,300 7,990 9,190 15,900 6,700 4,010 1,530 1,600 2,180 27 11,100 12,600 12,100 9,670 7,140 8,430 12,500 6,190 3,240 1,560 1,460 2,120 28 12,400 12,900 13,500 16,300 6,510 7,860 10,200 5,680 4,130 1,670 1,510 2,440 29 13,500 13,100 17,700 17,500 6,140 7,140 9,410 5,310 4,770 1,580 2,040 2,950 30 13,700 15,900 18,200 15,700 --- 6,610 7,780 5,930 4,230 2,010 1,850 3,620 31 14,600 --- 15,400 13,100 --- 6,120 --- 10,300 --- 2,210 1,580 --- Total 482,160 396,330 550,800 300,270 196,230 308,630 188,930 332,530 301,850 61,020 84,010 69,390 Mean 15,550 13,210 17,770 9,686 6,767 9,956 6,298 10,730 10,060 1,968 2,710 2,313 Max 28,900 17,300 33,200 17,500 11,400 14,000 18,900 19,700 25,200 3,350 7,140 6,470 Min 8,820 9,630 11,800 6,060 3,810 6,120 2,980 5,310 3,240 1,240 1,270 1,200 Cfsm 3.52 2.99 4.02 2.19 1.53 2.25 1.42 2.43 2.28 0.45 0.61 0.52 In. 4.06 3.33 4.63 2.53 1.65 2.60 1.59 2.80 2.54 0.51 0.71 0.58

STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1923 - 2012, BY WATER YEAR (WY) Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Mean 4,649 7,009 8,130 7,372 7,538 13,120 19,470 11,800 6,655 3,617 3,038 3,146 Max 25,910 18,580 20,380 18,900 18,400 45,780 37,440 27,810 23,660 15,340 11,490 19,650 (WY) (2006) (2007) (1997) (2006) (1970) (1936) (1987) (2006) (1984) (2009) (2008) (1938) Min 1,036 1,792 2,127 1,621 2,105 4,132 6,298 4,093 1,825 1,161 901 895 (WY) (1965) (2002) (1930) (1925) (1931) (1940) (2012) (1941) (1964) (1965) (1965) (1957)

— 2 — Water-Data Report 2012 01100000 MERRIMACK RIVER BELOW CONCORD RIVER AT LOWELL, MA—Continued

SUMMARY STATISTICS Calendar Year 2011 Water Year 2012 Water Years 1923 - 2012 Annual total 4,406,230 3,272,150 Annual mean 12,070 8,940 7,960 Highest annual mean 14,590 2006 Lowest annual mean 3,068 1965 Highest daily mean 38,800 Mar 9 33,200 Dec 9 161,000 Mar 20, 1936 Lowest daily mean 1,230 Aug 6 1,200 Sep 17 199 Sep 23, 1923 Annual seven-day minimum 1,470 Aug 2 1,350 Jul 19 581 Sep 12, 1995 Maximum peak flow 34,400 Dec 9 173,000 Mar 20, 1936 Maximum peak stage 49.89 Dec 9 a68.40 Mar 20, 1936 Instantaneous low flow 758 Aug 2 Annual runoff (cfsm) 2.73 2.02 1.80 Annual runoff (inches) 37.08 27.53 24.46 10 percent exceeds 25,400 16,200 17,800 50 percent exceeds 10,500 7,920 5,420 90 percent exceeds 3,000 1,650 1,670 a From floodmarks.

100,000

50,000

20,000

10,000

5,000 MEAN DISCHARGE, CUBICSECOND FEET PER

2,000

1,000 O N D J F M A M J J A S 2011 2012

— 3 —