Prepared in cooperation with the

States of New Hampshire and Vermont and with other agencies

Hydrologic Conditions in New Hampshire and 

Vermont, Water Year 2011

Open-File Report 2013–1135

U.S. Department of the Interior

U.S. Geological Survey
THIS PAGE INTENTIONALLY LEFT BLANK
Hydrologic Conditions in New Hampshire 

and Vermont, Water Year 2011

By Richard G. Kiah, Jason D. Jarvis, Robert F. Hegemann, Gregory S. Hilgendorf, 

and Sanborn L. Ward

Prepared in cooperation with the 

States of New Hampshire and Vermont and with other agencies

Open-File Report 2013–1135

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

SALLY JEWELL, Secretary

U.S. Geological Survey

Suzette M. Kimball, Acting Director

U.S. Geological Survey, Reston, Virginia: 2013

For more information on the USGS—the Federal source for science about the Earth, its natural and living 

resources, natural hazards, and the environment, visit http://www.usgs.gov or call 1–888–ASK–USGS.

For an overview of USGS information products, including maps, imagery, and publications, 

visit http://www.usgs.gov/pubprod

To order this and other USGS information products, visit http://store.usgs.gov

Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the 

U.S. Government.

Although this information product, for the most part, is in the public domain, it also may contain copyrighted materials 

as noted in the text. Permission to reproduce copyrighted items must be secured from the copyright owner.

Suggested citation:

Kiah, R.G., Jarvis, J.D., Hegemann, R.F., Hilgendorf, G.S., and Ward, S.L., 2013, Hydrologic conditions in 

New Hampshire and Vermont, water year 2011: U.S. Geological Survey Open-File Report 2013–1135, 36 p., 

http://pubs.usgs.gov/of/2013/1135/.
iii

Contents

Abstract...........................................................................................................................................................1

Introduction.....................................................................................................................................................1

Purpose and Scope ..............................................................................................................................1

Historical Records ................................................................................................................................1

Cooperators for Data Collection in New Hampshire and Vermont...............................................2

Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011..........................................2

Precipitation...........................................................................................................................................2

Surface-Water Streamflow...............................................................................................................10

Androscoggin River Basin........................................................................................................10

Saco River Basin........................................................................................................................10

Piscataqua River Basin.............................................................................................................10

Merrimack River Basin .............................................................................................................10

Connecticut River Basin ...........................................................................................................10

Hudson River Basin ...................................................................................................................10

St. Lawrence River Basin .........................................................................................................10

Reservoir and Lake Elevations .........................................................................................................13

Groundwater Levels ...........................................................................................................................13

Floods ..................................................................................................................................................13

Flood of April 26–29, 2011..........................................................................................................13

Flood of May 27, 2011 ................................................................................................................23

Lake Champlain..........................................................................................................................23

Flood of August 28 to September 2, 2011 ...............................................................................23

Summary........................................................................................................................................................23

Acknowledgments.......................................................................................................................................24

References Cited..........................................................................................................................................24

Figures

1. Map showing U.S. Geological Survey surface-water gaging stations in New 

Hampshire and Vermont..............................................................................................................3

2. Map showing U.S. Geological Survey groundwater wells in New Hampshire and 

Vermont ..........................................................................................................................................4

3. Graphs showing computed annual runoff in A, New Hampshire and B, Vermont for 

1901 to 2011..................................................................................................................................11

4. Maps showing annual runoff for water year 2011, as a percentile of historical 

streamflow, by hydrologic cataloging units (HUC8) in New Hampshire and Vermont....12

5. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1941–2010 at station 01052500 

Diamond River near Wentworth Location, New Hampshire, and B, annual mean 

streamflow for water years 1941–2011, and 25th, 50th, and 75th percentiles for 

annual mean streamflows.........................................................................................................26
iv

6. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1904–10, 1929–2010 at station 

01064500 Saco River near Conway, New Hampshire, and B, annual mean streamflow 

for water years 1904–10, 1929–2011, and 25th, 50th, and 75th percentiles for annual 

mean streamflows ......................................................................................................................27

7. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1934–2010 at station 01073500 

Lamprey River near Newmarket, New Hampshire, and B, annual mean streamflow 

for water years 1934–2011, and 25th, 50th, and 75th percentiles for annual mean 

streamflows .................................................................................................................................28

8. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1904–2010 at station 01076500 

Pemigewasset River at Plymouth, New Hampshire, and B, annual mean streamflow 

for water years 1904–2011, and 25th, 50th, and 75th percentiles for annual mean 

streamflows .................................................................................................................................29

9. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1937–2010 at station 01092000 

Merrimack River near Goffs Falls, below Manchester, New Hampshire, and B, annual 

mean streamflow for water years 1937–2011, and 25th, 50th, and 75th percentiles for 

annual mean streamflows. .......................................................................................................30

10. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1939–2010 at station 01137500 

Ammonoosuc River at Bethlehem Junction, New Hampshire, and B, annual mean 

streamflow for water years 1939–2011, and 25th, 50th, and 75th percentiles for 

annual mean streamflows.........................................................................................................31

11. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1916–2010 at station 01144000 

White River at West Hartford, Vermont, and B, annual mean streamflow for water 

years 1916–2011, and 25th, 50th, and 75th percentiles for annual mean streamflows ..32

12. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1931–2010 at station 01334000 

Walloomsac River near North Bennington, Vermont, and B, annual mean streamflow 

for water years 1931–2011, and 25th, 50th, and 75th percentiles for annual 

mean streamflows ......................................................................................................................33

13. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1911–20 and 1929–2010 at 

station 04282500 Otter Creek at Middlebury, Vermont, and B, annual mean streamflow 

for water years 1911–20 and 1929–2011, and 25th, 50th, and 75th percentiles for 

annual mean streamflows.........................................................................................................34

14. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1935–2010 at station 04287000 

Dog River at Northfield Falls, Vermont, and B, annual mean streamflow for water 

years 1935–2011, and 25th, 50th, and 75th percentiles for annual mean streamflows ...35

15. Graphs showing A, daily mean streamflow for water year 2011 and daily maximum, 

minimum, and average streamflows for water years 1917–19, 1922, 1923, and 

1929–2010 at station 04293500 Missisquoi River near East Berkshire, Vermont, and 

B, annual mean streamflow for water years 1917–19, 1922, 1923, and 1929–2011, and 

25th, 50th, and 75th percentiles for annual mean streamflows ..........................................36

16. Graphs showing locations of selected lakes or reservoirs in New Hampshire and 

Vermont and corresponding month-end contents, water year 2011 .................................14
v

17. Graphs showing A, daily mean surface-water elevation at station 04294500 Lake 

Champlain at Burlington, Vermont, water year 2011, and daily maximum, minimum, 

and average elevations for water years 1940–2010 and B, annual mean elevations 

for water years 1940–2011, and the 25th, 50th, and 75th percentiles.................................15

18. Boxplot showing daily mean depths to water in groundwater well 431500714528011, 

NH-WCW1, Town of Warner, New Hampshire, water year 2011, in relation to the 

distribution of monthly mean depths to water, water years 1965–2010.............................17

19. Scatterplot showing annual peak streamflows at selected streamgages in 

New Hampshire and Vermont, water year 2011, in relation to the contributing 

drainage area, with envelope lines and a regression line relating the 100-year 

streamflow to drainage area ....................................................................................................22

Tables

1. Description of streamgages in New Hampshire and Vermont .............................................5

2. Description of groundwater wells in New Hampshire and Vermont...................................9

3. Month-end groundwater-level conditions for 38 wells in New Hampshire and 

Vermont, water year 2011..........................................................................................................16

4. Peak stages and streamflows for selected New Hampshire and Vermont 

streamgages during record flooding in April, May, and August, water year 2011, and 

historical peak streamflows......................................................................................................18

Conversion Factors and Datum

Inch/Pound to SI

Multiply By To obtain

Length

inch (in.) 2.54 centimeter (cm)

foot (ft) 0.3048 meter (m)

Area

square mile (mi2) 2.590 square kilometer (km2)

Flow rate

cubic foot per second (ft3/s) 0.02832 cubic meter per second (m3/s)

Horizontal coordinate information is referenced to the North American Datum of 1983 (NAD 83).

Vertical coordinate information is referenced to the National Geodetic Vertical Datum of 1929 

(NGVD 29).

Elevation, as used in this report, refers to distance above the vertical datum.
THIS PAGE INTENTIONALLY LEFT BLANK
Hydrologic Conditions in New Hampshire and Vermont, 

Water Year 2011

By Richard G. Kiah, Jason D. Jarvis, Robert F. Hegemann, Gregory S. Hilgendorf, and Sanborn L. Ward

Abstract

Record-high hydrologic conditions in New Hampshire 

and Vermont occurred during water year 2011, according to 

data from 125 streamgages and lake gaging stations, 27 creststage gages, and 41 groundwater wells. Annual runoff for 

the 2011 water year was the sixth highest on record for New 

Hampshire and the highest on record for Vermont on the 

basis of a 111-year reference period (water years 1901–2011). 

Groundwater levels for the 2011 water year were generally 

normal in New Hampshire and normal to above normal 

in Vermont.

Record flooding occurred in April, May, and August of 

water year 2011. Peak-of-record streamflows were recorded at 

38 streamgages, 25 of which had more than 10 years of record. 

Flooding in April 2011 was widespread in parts of northern 

New Hampshire and Vermont; peak-of-record streamflows 

were recorded at nine streamgages. Flash flooding in May 

2011 was isolated to central and northeastern Vermont; peakof-record streamflows were recorded at five streamgages. 

Devastating flooding in August 2011 occurred throughout 

most of Vermont and in parts of New Hampshire as a result of 

the heavy rains associated with Tropical Storm Irene. Peak-ofrecord streamflows were recorded at 24 streamgages.

Introduction

The U.S. Geological Survey, in cooperation with State 

agencies, obtains a large amount of data pertaining to the 

water resources of New Hampshire and Vermont each water 

year1. These data, accumulated during many water years, 

constitute a valuable database for developing an improved 

understanding of the water resources of the two States. To 

make these data readily available to interested parties outside 

the U.S. Geological Survey, they are published annually and 

are available online at http://water.usgs.gov.

1

A water year is the 12-month period October 1 through September 30. It is 

designated by the calendar year in which it ends and which includes 9 of the 

12 months. 

Record-high hydrologic conditions in New Hampshire 

and Vermont occurred during water year 2011. Major flooding 

was documented in April, May, and August. Widespread damage caused by the flooding led President Barack H. Obama 

to declare major disasters in parts of New Hampshire for the 

floods in May and August and in parts of Vermont for floods in 

April, May, and August.

Purpose and Scope

This report summarizes hydrologic conditions and 

flooding in New Hampshire and Vermont for water year 

2011. Records of stage and flow of streams, contents of lakes 

and reservoirs, and water levels of groundwater wells are 

included. In water year 2011, hydrologic data were collected 

at 125 streamgages and lake gaging stations, 27 crest-stage 

gages, and 41 groundwater wells. The severity of record floods 

in water year 2011 is summarized in terms of annual peak 

streamflows related to historical peak streamflows at 

selected streamgages. 

Historical Records

Prior to 1960, water-resources data for New Hampshire 

and Vermont were published in U.S. Geological Survey 

Water-Supply Papers. Data on streamflow and stage and 

on lake or reservoir contents and stage, through September 

1960, were published annually under the title “Surface-Water 

Supply of the United States, Parts 1A and 1B.” For the 1961 

through 1970 water years, the data were published in two 

5-year reports. Data on chemical quality, temperature, and 

suspended sediment for the 1941 through 1970 water years 

were published annually under the title “Quality of Surface 

Waters of the United States,” and data on water levels for the 

1939 through 1974 water years were published under the title 

“Ground-Water Levels in the United States.”

From 1961 to 1974, surface-water quantity data for 

New Hampshire and Vermont were published in annual reports 

as “Water Resources Data for Massachusetts, New Hampshire, 

Rhode Island, and Vermont.” For the 1964 water year, a similar report was introduced that contained only data relating to 

water quality. Beginning with the 1975 water year, the report 
2 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

format was changed to present, in one volume, data on quantities of surface water, quality of surface water and groundwater, 

and groundwater levels. These official reports have an identification number consisting of the two-letter State abbreviation, 

the last two digits of the water year, and the volume number. 

For example, the water year 2005 volume is identified as 

“U.S. Geological Survey Water-Data Report NH–VT–05–1.”

Publication of site-specific data pages began in water year 

2006. Data pages for individual sites published by the U.S. 

Geological Survey for all States are available on the Internet at 

http://wdr.water.usgs.gov/.

Real-time and historical data from the surface-water 

network, as well as information about individual sites, are 

available through the Internet at http://waterdata.usgs.gov/usa/

nwis/rt.

Cooperators for Data Collection in New 

Hampshire and Vermont

The U.S. Geological Survey and organizations of the 

States of New Hampshire and Vermont have had cooperative 

agreements for the systematic collection of surface-water 

data since the early 1900s, and for groundwater data since 

the mid-1960s. Organizations that assisted in collecting the 

data in this report through cooperative agreements with the 

U.S. Geological Survey are

• New Hampshire Department of Environmental 

Services;

• Vermont Department of Environmental Conservation;

• Vermont Department of Forests, Parks, and Recreation;

• Vermont Agency of Transportation;

• Maine Emergency Management;

• Maine River Flow Advisory Commission;

• New England Interstate Water Pollution Control 

Commission;

• City of Keene, N.H.;

• City of Rochester, N.H.;

• Town of Salem, N.H.;

• Lake Champlain Basin Program;

• City of South Burlington, Vt.;

• City of Montpelier, Vt.; and

• Town of Burke, Vt.

Assistance in the form of funds or services was provided 

by the U.S. Army Corps of Engineers for the collection of data 

at 19 streamgages in 2011. Organizations supplying data are 

acknowledged in the National Water Information System: Web 

Interface.

The following organizations contributed funds and 

services through the requirements of the Federal Energy 

Regulatory Commission:

• Green Mountain Power Company, 

• Great Bay Hydro Corporation,

• Public Service Company of New Hampshire, and

• Florida Power and Light Company.

Hydrologic Conditions in New 

Hampshire and Vermont, Water Year 

2011

Hydrologic conditions in New Hampshire and 

Vermont were characterized through the use of data from 

125 streamgages and lake gaging stations, 27 crest-stage 

gages, and 41 groundwater wells (figs. 1 and 2, tables 1 and 

2). This section describes hydrologic conditions in terms of 

precipitation, streamflow, lake and reservoir elevations, and 

groundwater levels.

Precipitation

During the 2011 water year, precipitation trends for the 

States of New Hampshire and Vermont were observed at the 

upper end of historical levels. An abnormally high snowpack 

during the 2010–11 winter, spring thunderstorms, and Tropical 

Storm Irene in August resulted in the third highest annual 

accumulated precipitation in New Hampshire and the highest 

level ever recorded in Vermont, according to precipitation 

data collected by the National Oceanic and Atmospheric 

Administration since 1895 (National Oceanic and Atmospheric 

Administration, 2011).

New Hampshire has experienced an increase in precipitation trends over the past 5 years with the top 3 years of 

annual accumulated precipitation on record occurring during 

water years 2006–2011 (National Oceanic and Atmospheric 

Administration, 2011). Water year 2006 had the highest annual 

accumulated precipitation of 66.65 inches (in.), followed by 

2008 at 59.94 in. and 2011 at 57.70 in. Accumulated annual 

precipitation for the 2011 water year in Vermont was 62.46 in.; 

the second highest accumulated precipitation was 58.44 in. in 

water year 1928.

Snowpack data collected by New Hampshire Department 

of Environmental Services (2011) and the U.S. Army Corps of 

Engineers (2011) show region-wide snow-water equivalents 

reaching 7 in. at the height of the 2010–11 winter snowpack. 

The snowpack had an average water equivalent of 5 in. by 

April 1, 2011, and was completely gone by the end of the 

month (National Weather Service, 2011).
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 3

1

2

3

4

5

6 7

8

9

10

11

12 13

14 15

16

17

18

19 20

21

22

24 23

25

26

27

28

29

30

31

32

33

34

35

36

37

38 39 40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66 67

68

69

70

71

72

73

74

75 76

77

78

79 80

81

82

83

84

85

86

88 87

89

90

91

92

93

94

95

97

98

99

101 100

103 102

105 104

106

108

110 109

111

112

114

115

116

117 118

119

120

121

122

113

126

125

128

129

130

131

132

133

134

135

136

137

138

140

141

143 142

144

145

146

147

148 149

150 151

152

139

127 124

107

123

96

129

146

127

EXPLANATION

Real-time streamgage and identifier

Real-time educational site and identifier

Crest-stage gage and identifier

0

0

50 MILES

50 KILOMETERS

MASSACHUSETTS

NEW

YORK

MAINE

CANADA

Essex

Hudson

River Basin

Merrimack

River Basin

Piscataqua

River Basin

Connecticut

River Basin

Saco

River Basin

St. Lawrence

River Basin

73o 72o

45o

44o

43o

71o

revi R

kca imrre M

Lake

Winnipesaukee

Lake

Champlain

Connecticut River

Franklin

Orleans

Lamoille

Caledonia

Grafton

Carroll

Chittenden

Washington

Addison Orange

Rutland

Windsor

Bennington

Windham

Belknap

Sullivan Strafford

Rockingham

Merrimack

Cheshire

Hillsborough

Androscoggin

River Basin

NEW HAMPSHIRE

VERMONT

Coos

Base from U.S. Geological Survey Digital line graphs,

1:24,000 or 1:25,000 scale, 1983.

Major watersheds from U.S. Geological Survey 

1:2,000,000-scale Hydrologic Unit Boundaries, 1999.

Figure 1. U.S. Geological Survey surface-water gaging stations in New Hampshire and Vermont.
4 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

MASSACHUSETTS

NEW

YORK

MAINE

CANADA

Essex

EXPLANATION

Real-time bedrock well and site name

Unconsolidated well and site name

Real-time unconsolidated well and site name

Hudson

River Basin

Merrimack

River Basin

Piscataqua

River Basin

Connecticut

River Basin

Saco

River Basin

St. Lawrence

River Basin

revi R

kca imrre M

Lake

Winnipesaukee

Lake

Champlain

Connecticut River

0

0

50 MILES

50 KILOMETERS

73o 72o

45o

44o

43o

71o

VT-MGW 11

VT-PFW 8

VT-RJW 1

VT-MPW 1

VT-GLW 1

VT-WOW 1

NH-PBW 148

NH-KEW 2

VT-PQW 1

NH-PBW 148

Franklin

Orleans

Lamoille

Caledonia

Grafton

Carroll

Chittenden

Washington

Addison Orange

Rutland

Windsor

Bennington

Windham

Belknap

Sullivan Strafford

Rockingham

Merrimack

Cheshire

Hillsborough

Coos

Androscoggin

River Basin

NEW HAMPSHIRE

VERMONT

VT-WAW 2

VT-MJW 3

VT-BIW 1

NH-CTW 73

NH-ETW 1

NH-LCW 1

NH-SJW 2

VT-CKW 1

VT-HLW 54

NH-LLW 19

NH-CBW 34

NH-ENW 30

NH-ADW 14/15

NH-OXW 38

NH-GTW 141

NH-DDW 46 NH-EPW 90

NH-FKW 1 NH-NLW 1

NH-WCW 1 NH-CVW 2

NH-CVW 4

NH-NAW 218

NH-GSW 75

NH-HTW 5

NH-NFW 53

NH-LIW 1

NH-NPW 3/6 NH-BAW 10

NH-CVW 312

NH-ETW 1

NH-WCW 1 

Base from U.S. Geological Survey Digital line graphs,

1:24,000 or 1:25,000 scale, 1983.

Major watersheds from U.S. Geological Survey 

1:2,000,000-scale Hydrologic Unit Boundaries, 1999.

NH-HTW 5 Bedrock well and site name

Figure 2. U.S. Geological Survey groundwater wells in New Hampshire and Vermont.
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 5

Table 1. Description of streamgages in New Hampshire and Vermont.—Continued

[mi2, square mile; na, not applicable; NH, New Hampshire; MA, Massachusetts; VT, Vermont; misc., miscellaneous]

Site Station 

number Station name

Drainage 

area 

mi2)

Record type

Androscoggin River Basin

1 01052500 DIAMOND RIVER NEAR WENTWORTH LOCATION, NH 152 Discharge

2 01053500 ANDROSCOGGIN RIVER AT ERROL, NH 1,046 Discharge

3 01053600 ANDROSCOGGIN RIVER BELOW BOG BROOK AT CAMBRIDGE, NH 1,177 Discharge

4 01054000 ANDROSCOGGIN RIVER NEAR GORHAM, NH 1,361 Discharge

Saco River Basin

5 010642505 SACO RIVER AT RIVER STREET, AT BARTLETT, NH 91 Discharge

6 01064485 SWIFT RIVER 0.5 MI BELOW HOBBS BR, NR CONWAY, NH 76.8 Discharge

7 01064500 SACO RIVER NEAR CONWAY, NH 385 Discharge

8 01064801 BEARCAMP RIVER AT SOUTH TAMWORTH, NH 67.6 Discharge

Piscataquo River Basin

9 01072800 COCHECO RIVER NEAR ROCHESTER, NH 85.7 Discharge

10 01072870 ISINGLASS R AT ROCHESTER NECK RD, NR DOVER, NH 73.6 Discharge

11 01073000 OYSTER RIVER NEAR DURHAM, NH 12.1 Discharge

12 01073319 LAMPREY RIVER AT LANGFORD ROAD, AT RAYMOND, NH 55.7 Discharge

13 01073500 LAMPREY RIVER NEAR NEWMARKET, NH 183 Discharge

14 010735562 EXETER RIVER AT ODELL ROAD, NEAR SANDOWN, NH 16.1 Discharge

15 01073587 EXETER RIVER AT HAIGH ROAD, NEAR BRENTWOOD, NH 63.5 Discharge

16 01073785 WINNICUT RIVER AT GREENLAND, NR PORTSMOUTH, NH 14.1 Discharge

Merrimack River Basin

17 01074520 EAST BRANCH PEMIGEWASSET RIVER AT LINCOLN, NH 115 Discharge

18 01075000 PEMIGEWASSET RIVER AT WOODSTOCK, NH 193 Discharge

19 01076000 BAKER RIVER NEAR RUMNEY, NH 143 Discharge

20 01076500 PEMIGEWASSET RIVER AT PLYMOUTH, NH 622 Discharge

21 01077400 COCKERMOUTH RIVER BELOW HARDY BROOK, AT GROTON, NH 21.4 Discharge

22 01078000 SMITH RIVER NEAR BRISTOL, NH 85.8 Discharge

23 01081000 WINNIPESAUKEE RIVER AT TILTON, NH 471 Discharge

24 01081500 MERRIMACK RIVER AT FRANKLIN JUNCTION, NH 1,507 Discharge

25 01082000 CONTOOCOOK RIVER AT PETERBOROUGH, NH 68.1 Discharge

26 01083000 NUBANUSIT BK BLW MACDOWELL DAM NR PETERBOROUGH NH 44 Peak discharge

27 01084000 NORTH BRANCH RIVER NEAR ANTRIM, NH 54.8 Discharge

28 01085000 CONTOOCOOK RIVER NEAR HENNIKER, NH 368 Peak discharge

29 01085500 CONTOOCOOK R BL HOPKINTON DAM AT W HOPKINTON, NH 427 Discharge

30 01086000 WARNER RIVER AT DAVISVILLE, NH 146 Discharge

31 01087000 BLACKWATER RIVER NEAR WEBSTER, NH 129 Peak discharge

32 01089100 SOUCOOK RIVER, AT PEMBROKE ROAD, NEAR CONCORD, NH 81.9 Discharge

33 01089500 SUNCOOK RIVER AT NORTH CHICHESTER, NH 157 Discharge

34 01090800 PISCATAQUOG RIVER BL EVERETT DAM, NR E WEARE, NH 63.1 Peak discharge

35 01091000 SOUTH BRANCH PISCATAQUOG RIVER NEAR GOFFSTOWN, NH 104 Discharge

36 01091500 PISCATAQUOG RIVER NEAR GOFFSTOWN, NH 202 Peak discharge

37 01092000 MERRIMACK R NR GOFFS FALLS, BELOW MANCHESTER, NH 3,092 Discharge
6 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

Table 1. Description of streamgages in New Hampshire and Vermont.—Continued

[mi2, square mile; na, not applicable; NH, New Hampshire; MA, Massachusetts; VT, Vermont; misc., miscellaneous]

Site Station 

number Station name

Drainage 

area 

(mi2)

Record type

Merrimack River Basin—Continued

38 01093852 SOUHEGAN RIVER (SITE WLR-1) NEAR MILFORD, NH 103 Discharge

39 01094000 SOUHEGAN RIVER AT MERRIMACK, NH 171 Discharge

40 010965852 BEAVER BROOK AT NORTH PELHAM, NH 47.8 Discharge

41 01100505 SPICKET RIVER AT NORTH SALEM, NH 16.5 Discharge

42 01100561 SPICKET RIVER NEAR METHUEN, MA 62.1 Discharge

Connecticut River Basin

43 01129200 CONNECTICUT R BELOW INDIAN STREAM NR PITTSBURG, NH 254 Discharge

44 01129420 CAPON BROOK AT VT 102, NEAR CANAAN, VT 4.71 Peak discharge

45 01129500 CONNECTICUT RIVER AT NORTH STRATFORD, NH 799 Discharge

46 01130000 UPPER AMMONOOSUC RIVER NEAR GROVETON, NH 232 Discharge

47 01131500 CONNECTICUT RIVER NEAR DALTON, NH 1,514 Discharge

48 01133000 EAST BRANCH PASSUMPSIC RIVER NEAR EAST HAVEN, VT 53.8 Discharge

49 01133200 QUIMBY BROOK NEAR LYNDONVILLE, VT 2.32 Peak discharge

50 01134500 MOOSE RIVER AT VICTORY, VT 75.2 Discharge

51 01134800 KIRBY BROOK AT CONCORD, VT 8.05 Peak discharge

52 01135150 POPE BROOK (SITE W-3) NEAR NORTH DANVILLE, VT 3.25 Discharge

53 01135300 SLEEPERS RIVER (SITE W-5) NEAR ST. JOHNSBURY, VT 42.9 Discharge

54 01135500 PASSUMPSIC RIVER AT PASSUMPSIC, VT 436 Discharge

55 01135700 JOES BROOK TRIBUTARY NEAR EAST BARNET, VT 0.76 Peak discharge

56 01137500 AMMONOOSUC RIVER AT BETHLEHEM JUNCTION, NH 87.6 Discharge

57 01137940 AMMONOOSUC RIVER BELOW LISBON DAM, AT LISBON, NH 288 Discharge

58 01138500 CONNECTICUT RIVER AT WELLS RIVER, VT 2,644 Discharge

59 01139000 WELLS RIVER AT WELLS RIVER, VT 98.4 Discharge

60 01139700 WAITS RIVER TRIBUTARY NEAR WEST TOPSHAM, VT 1.09 Peak discharge

61 01139800 EAST ORANGE BRANCH AT EAST ORANGE, VT 8.95 Discharge

62 01141500 OMPOMPANOOSUC RIVER AT UNION VILLAGE, VT 130 Peak discharge

63 01142400 THIRD BRANCH WHITE RIVER TRIBUTARY AT RANDOLPH, VT 0.77 Peak discharge

64 01142500 AYERS BROOK AT RANDOLPH, VT 30.5 Discharge

65 01144000 WHITE RIVER AT WEST HARTFORD, VT 690 Discharge

66 01144500 CONNECTICUT RIVER AT WEST LEBANON, NH 4,092 Discharge

67 01150800 KENT BROOK NEAR KILLINGTON, VT 3.31 Peak discharge

68 01150900 OTTAUQUECHEE RIVER NEAR WEST BRIDGEWATER, VT 23.4 Peak discharge

69 01151200 OTTAUQUECHEE RIVET TRIBUTARY NEAR QUECHEE, VT 0.82 Peak discharge

70 01151500 OTTAUQUECHEE RIVER AT NORTH HARTLAND, VT 221 Discharge

71 01152500 SUGAR RIVER AT WEST CLAREMONT, NH 269 Discharge

72 01153000 BLACK RIVER AT NORTH SPRINGFIELD, VT 158 Peak discharge

73 01153300 MIDDLE BRANCH WILLIAMS RIVER TRIBUTARY AT CHESTER, VT 3.16 Peak discharge

74 01153550 WILLIAMS RIVER NEAR ROCKINGHAM VT 112 Discharge

75 01154000 SAXTONS RIVER AT SAXTONS RIVER, VT 72.2 Discharge

76 01154500 CONNECTICUT RIVER AT NORTH WALPOLE, NH 5,493 Discharge
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 7

Table 1. Description of streamgages in New Hampshire and Vermont.—Continued

[mi2, square mile; na, not applicable; NH, New Hampshire; MA, Massachusetts; VT, Vermont; misc., miscellaneous]

Site Station 

number Station name

Drainage 

area 

(mi2)

Record type

Connecticut River Basin—Continued

77 01154950 COLD RIVER AT HIGH STREET, AT ALSTEAD, NH 74.6 Discharge

78 01155349 WEST RIVER BELOW WINHALL RIVER, NEAR JAMAICA, VT 161 Misc. measurements

79 01155350 WEST RIVER TRIBUTARY AT RT 30, NEAR JAMAICA, VT 0.9 Peak discharge

80 01155500 WEST RIVER AT JAMAICA, VT 179 Discharge

81 01155910 WEST RIVER BELOW TOWNSHEND DAM NEAR TOWNSHEND, VT 282 Peak discharge

82 01156300 WHETSTONE BROOK TRIBUTARY NEAR MARLBORO, VT 1.05 Peak discharge

83 01156450 CONNECTICUT RIVER TRIBUTARY NEAR VERNON, VT 1.12 Peak discharge

84 01157000 ASHUELOT RIVER NEAR GILSUM, NH 71.1 Discharge

85 01158000 ASHUELOT RIVER BELOW SURRY MT DAM, NEAR KEENE, NH 101 Discharge

86 01158600 OTTER BROOK BELOW OTTER BROOK DAM, NEAR KEENE, NH 47.2 Peak discharge

87 01160000 S BR ASHUELOT RIVER AT WEBB, NR MARLBOROUGH, NH 36 Discharge

88 01160350 ASHUELOT RIVER AT WEST SWANZEY, NH 316 Discharge

89 01161000 ASHUELOT RIVER AT HINSDALE, NH 420 Discharge

Hudson River Basin

90 01334000 WALLOOMSAC RIVER NEAR NORTH BENNINGTON, VT 111 Discharge

St. Lawrence River Basin

91 04279400 POULTNEY RIVER TRIBUTARY AT EAST POULTNEY, VT 1.13 Peak discharge

92 04279490 LAKE BOMOSEEN AT OUTLET, NEAR FAIR HAVEN, VT 37.5 Stage

93 04280000 POULTNEY RIVER BELOW FAIR HAVEN, VT 187 Discharge

94 04280240 METTAWEE RIVER TRIBUTARY NO. 3 AT VT 30, AT EAST RUPERT, VT 2.59 Peak discharge

95 04280910 MOON BROOK BELOW MUSSEY BROOK AT RUTLAND, VT 8.29 Discharge

96 04282000 OTTER CREEK AT CENTER RUTLAND, VT 307 Discharge

97 04282300 BRANDY BROOK AT BREAD LOAF, VT 2.24 Peak discharge

98 04282500 OTTER CREEK AT MIDDLEBURY, VT 628 Discharge

99 04282525 NEW HAVEN RIVER AT BROOKSVILLE, NR MIDDLEBURY, VT 115 Discharge

100 04282600 LITTLE OTTER CREEK TRIBUTARY NEAR BRISTOL, VT 1.48 Peak discharge

101 04282650 LITTLE OTTER CREEK AT FERRISBURG, VT. 57.1 Discharge

102 04282700 LEWIS CREEK TRIBUTARY AT STARKSBORO, VT 5.31 Peak discharge

103 04282780 LEWIS CREEK AT NORTH FERRISBURG, VT. 77.2 Discharge

104 04282795 LAPLATTE RIVER AT SHELBURNE FALLS, VT. 44.6 Discharge

105 04282800 MUNROE BROOK AT SHELBURNE, VT 5.35 Discharge

106 04282805 BARTLETT BROOK AT SOUTH BURLINGTON, VT 1.04 Discharge

107 04282813 POTASH BR AT QUEEN CITY PARK RD, NR BURLINGTON, VT 7.18 Discharge

108 04283500 EAST BARRE DETENTION RESERVOIR AT EAST BARRE, VT 38.8 Stage

109 04285000 WRIGHTSVILLE DETENTION RESERVOIR AT WRIGHTSVILLE, VT 66.5 Stage

110 04285500 NORTH BRANCH WINOOSKI RIVER AT WRIGHTSVILLE, VT 69.2 Discharge

111 04286000 WINOOSKI RIVER AT MONTPELIER, VT 397 Discharge

112 04287000 DOG RIVER AT NORTHFIELD FALLS, VT 76.1 Discharge

113 04287300 SUNNY BROOK NEAR MONTPELIER, VT 2.31 Peak discharge

114 04288000 MAD RIVER NEAR MORETOWN, VT 139 Discharge
8 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

Table 1. Description of streamgages in New Hampshire and Vermont.—Continued

[mi2, square mile; na, not applicable; NH, New Hampshire; MA, Massachusetts; VT, Vermont; misc., miscellaneous]

Site Station 

number Station name

Drainage 

area 

(mi2)

Record type

St. Lawrence River Basin—Continued

115 04288225 W BRANCH LITTLE R ABV BINGHAM FALLS NEAR STOWE, VT 4.67 Discharge

116 04288230 RANCH BROOK AT RANCH CAMP, NEAR STOWE, VT 3.8 Discharge

117 04288400 BRYANT BROOK AT WATERBURY CENTER, VT 2.64 Peak discharge

118 04288500 WATERBURY RESERVOIR NEAR WATERBURY, VT 109 Stage

119 04289000 LITTLE RIVER NEAR WATERBURY, VT 111 Discharge

120 04289600 WINOOSKI RIVER TRIBUTARY NEAR RICHMOND, VT 0.71 Peak discharge

121 04290335 ALLEN BROOK AT VT 2A, NEAR ESSEX JUNCTION, VT 9.9 Discharge

122 04290500 WINOOSKI RIVER NEAR ESSEX JUNCTION, VT 1,044 Discharge

123 04290575 INDIAN BROOK NEAR ESSEX JUNCTION, VT 6.48 Discharge

124 04290700 BAILEY BROOK AT EAST HARDWICK, VT 2.52 Peak discharge

125 04292000 LAMOILLE RIVER AT JOHNSON, VT 310 Discharge

126 04292100 STONY BROOK NEAR EDEN, VT 4.21 Peak discharge

127 04292355 MORGAN BR TRIB AT OLD NO 11 RD, NEAR WESTFORD, VT 2.15 Peak discharge

128 04292500 LAMOILLE RIVER AT EAST GEORGIA, VT 686 Discharge

129 04292750 MILL RIVER AT GEORGIA SHORE RD, NR ST ALBANS, VT 22.3 Discharge

130 04292770 STEVENS BROOK AT LEMNAH DRIVE, AT ST ALBANS, VT 1.54 Discharge

131 04292795 STEVENS BROOK AT KELLOGG ROAD, NEAR ST. ALBANS, VT 6.95 Discharge

132 04292810 JEWETT BROOK AT VT 38, NEAR ST. ALBANS, VT 3.74 Discharge

133 04293000 MISSISQUOI RIVER NEAR NORTH TROY, VT 131 Discharge

134 04293200 MUD CREEK AT BEAR MOUNTAIN RD, NEAR NORTH TROY, VT 37.1 Discharge

135 04293005 DUNN BROOK AT VT100, NEAR NEWPORT CENTER, VT 2.85 Peak discharge

136 04293430 NORTH BRANCH ABOVE RIVER STREET, AT RICHFORD, VT 64.8 Discharge

137 04293500 MISSISQUOI RIVER NEAR EAST BERKSHIRE, VT 479 Discharge

138 04293600 TROUT RIVER AT HOPKINS BR, NR ENOSBURG FALLS, VT 78.6 Discharge

139 04293700 TYLER BRANCH AT DUFFY HILL RD NR ENOSBURG FALLS, VT 55.1 Discharge

140 04293795 BLACK CREEK ABOVE BRIDGE STREET, AT SHELDON, VT 119 Discharge

141 04293800 MISSISIQUOI RIVER TRIBUTARY AT SHELDON JUNCTION, VT 1.69 Peak discharge

142 04293900 HUNGERFORD BR AT HIGHGATE RD NR HIGHGATE CENTER, VT 18.6 Discharge

143 04294000 MISSISQUOI RIVER AT SWANTON, VT 850 Discharge

144 04294140 ROCK RIVER NEAR HIGHGATE CENTER, VT 11.3 Discharge

145 04294300 PIKE RIVER AT EAST FRANKLIN, NR ENOSBURG FALLS, VT 34.5 Discharge

146 04294500 LAKE CHAMPLAIN AT BURLINGTON, VT na Stage

147 04295500 LAKE MEMPHREMAGOG AT NEWPORT, VT na Stage

148 04296000 BLACK RIVER AT COVENTRY, VT 122 Discharge

149 04296150 LORD BROOK NEAR EVANSVILLE, VT 4.76 Peak discharge

150 04296280 BARTON RIVER NEAR COVENTRY, VT 155 Discharge

151 04296300 PHERRINS RIVER TRIBUTARY NEAR ISLAND POND, VT 1.05 Peak discharge

152 04296500 CLYDE RIVER AT NEWPORT, VT 142 Discharge
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 9

Table 2. Description of groundwater wells in New Hampshire and Vermont.

[Site name, U.S. Geological Survey local well number based on State, town, and a sequential number; Well depth, in feet below land 

surface datum; ft, feet]

Site number Site name County Well depth 

(ft) Local aquifer

New Hampshire

431916071125901 NH-BAW 10 Belknap 25.0 Stratified deposits, undifferentiated

434221071051501 NH-OXW 38 Carroll 114.7 Stratified deposits, undifferentiated

435948071220301 NH-ADW 14 Carroll 79.5 Stratified deposits, undifferentiated

435948071220302 NH-ADW 15 Carroll 18 Stratified deposits, undifferentiated

425543072175801 NH-KEW 2 Cheshire 18.0 Outwash

442450071052301 NH-SJW 2 Coos 40.7 Outwash

442830071321001 NH-LCW 1 Coos 30.0 Stratified deposits, undifferentiated

444733071094901 NH-ETW 1 Coos 30.0 Outwash

445334071291701 NH-CTW 73 Coos 27 Stratified deposits, undifferentiated

433616072074001 NH-ENW 30 Grafton 37.5 Stratified deposits, undifferentiated

434952071390901 NH-CBW 34 Grafton 106.6 Stratified deposits, undifferentiated

441401071531501 NH-LLW 19 Grafton 42. Stratified deposits, undifferentiated

424800071295301 NH-NAW 218 Hillsborough 42.5 Delta drift

425744071532001 NH-GSW 75 Hillsborough 68.0 Stratified deposits, undifferentiated

430235071275501 NH-HTW 5 Merrimack 103 Crystalline rocks, noncarbonate

431034071340501 NH-CVW 312 Merrimack 480 Bedrock

431049071324301 NH-CVW 4 Merrimack 40.7 Lacustrine deposits

431120071284201 NH-PBW 148 Merrimack 94 Bedrock

431224071303601 NH-CVW 2 Merrimack 60.0 Stratified deposits, undifferentiated

431540071452801 NH-WCW 1 Merrimack 43.0 Outwash

432343071570901 NH-NLW 1 Merrimack 21.0 Till

432428071390701 NH-FKW 1 Merrimack 52 Outwash

430212070505201 NH-GTW 141 Rockingham 405.0 Bedrock

430409071010101 NH-EPW 90 Rockingham 37. Stratified deposits, undifferentiated

430527071140101 NH-DDW 46 Rockingham 47.5 Stratified deposits, undifferentiated

430721071005001 NH-LIW 1 Strafford 32.8 Stratified deposits, undifferentiated

432534071095601 NH-NFW 53 Strafford 60. Stratified deposits, undifferentiated

432322072112401 NH-NPW 3 Sullivan 57 Stratified deposits, undifferentiated

432322072112402 NH-NPW 6 Sullivan 20 Stratified deposits, undifferentiated

Vermont

440016073070901 VT-MGW 11 Addison

424810073160401 VT-PQW 1 Bennington 17.8 Stratified deposits, undifferentiated

443646073124901 VT-MJW 3 Chittenden 40.0 Stratified deposits, undifferentiated

444731071514701 VT-BIW 1 Essex 35.0 Stratified deposits, undifferentiated

443405072323501 VT-MPW 1 Lamoille 50.0 Stratified deposits, undifferentiated

435343072151801 VT-WOW 1 Orange 54.0 Stratified deposits, undifferentiated

443952072114001 VT-GLW 1 Orleans 82.0 Stratified deposits, undifferentiated

434217073010601 VT-PFW 8 Rutland 42.0 Stratified deposits, undifferentiated

441215072483101 VT-WAW 2 Washington 45.5 Stratified deposits, undifferentiated

431551072350601 VT-CKW 1 Windsor 22.0 Stratified deposits, undifferentiated

433240072242901 VT-HLW 54 Windsor 51.0 Stratified deposits, undifferentiated

435129072483301 VT-RJW 1 Windsor 73.0 Stratified deposits, undifferentiated
10 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

Surface-Water Streamflow

Computed annual runoff for the 2011 water year was the 

sixth highest on record for New Hampshire and the highest on 

record for Vermont (fig. 3; U.S. Geological Survey, 2011a). 

The ranking is based on a 111-year reference period (water 

years 1901 to 2011). The 2011 annual runoff, in general, was 

greater than the 90th percentile of the reference period for 

New Hampshire and Vermont; some hydrologic cataloging 

units in the Connecticut and St. Lawrence River Basins had 

the highest recorded annual runoffs (fig. 4; U.S. Geological 

Survey, 2011b). Annual runoff in the Piscataqua River Basin in 

southern New Hampshire was generally in the normal range.

Streamflow data for 11 representative streamgages used 

as indicators of monthly runoff across both States are provided 

in figures 5 to 15 (in back of report). Daily mean streamflow 

for water year 2011 is shown in relation to historical maximum, minimum, and mean streamflows, and annual mean 

streamflow for the period of record is shown in relation to the 

25th, 50th, and 75th percentiles. Annual mean streamflows 

less than the 25th percentile are to be considered below normal; between the 25th and 75th percentile, normal; and above 

the 75th percentile, above normal. Hydrographs of monthly 

flow for the 11 representative streamgages are available on the 

Internet at http://nh.water.usgs.gov/WaterData/curr.htm.

Androscoggin River Basin

Annual runoff for the Androscoggin River Basin was 

recorded at four streamgages. Annual runoff was above normal 

and generally in the greater than 90th-percentile class (fig. 4). 

For example, annual mean streamflow for the Diamond River 

near Wentworth Location, N.H. (01052500), of 478 cubic feet 

per second (ft3/s) is the fifth highest on record (fig. 5, in back 

of report) and is 134 percent of the period of record annual 

mean of 358 ft3/s.

Saco River Basin

Annual runoff for the Saco River Basin was recorded 

at four streamgages. Annual runoff was above normal and 

generally in the greater than 90th-percentile class (fig. 4). For 

example, annual mean streamflow for the Saco River near 

Conway, N.H. (01064500), of 1,422 ft3/s is the fourth highest 

on record (fig. 6, in back of report) and is 147 percent of the 

period of record annual mean of 967 ft3/s.

Piscataqua River Basin

Annual runoff for the Piscataqua River Basin was 

recorded at eight streamgages. Annual runoff was normal 

(fig. 4). For example, annual mean streamflow for the 

Lamprey River near Newmarket, N.H. (01073500), of 289 ft3/s 

is the 40th highest on record (fig. 7, in back of report) and is 

99 percent of the period of record annual mean of 292 ft3/s.

Merrimack River Basin

Annual runoff for the Merrimack River Basin was 

recorded at 21 streamgages. Annual runoff was generally 

above normal and greater than the 90th percentile in northern parts of the basin (fig. 4). For example, annual mean 

streamflow for the Pemigewasset River at Plymouth, N.H. 

(01076500), of 2,207 ft3/s is the second highest on record 

(fig. 8, in back of report) and is 159 percent of the period of 

record annual mean of 1,389 ft3/s. The annual mean streamflow for the Merrimack River near Goffs Falls, below 

Manchester, N.H. (01092000), of 7,067 ft3/s is the 10th highest 

on record (fig. 9, in back of report) and is about 129 percent of 

the period of record annual mean of 5,486 ft3/s.

Connecticut River Basin

Annual runoff for the Connecticut River Basin was 

recorded at 29 streamgages. Annual runoff was generally 

greater than the 90th percentile; some subbasins in Vermont 

had the highest annual runoff on record (fig. 4). For example, 

annual mean streamflow for the Ammonoosuc River at 

Bethlehem Junction, N.H. (01137500), of 309 ft3/s is the third 

highest on record (fig. 10, in back of report) and is about 

144 percent of the period of record annual mean of 214 ft3/s. 

The annual mean streamflow for the White River at West 

Hartford, Vt. (01144000), of 2,258 ft3/s is the highest on 

record (fig. 11, in back of report) and is about 183 percent of 

the period of record annual mean of 1,231 ft3/s.

Hudson River Basin

Annual runoff for the Hudson River Basin was recorded 

at one streamgage. Annual runoff was generally greater than 

the 90th percentile (fig. 4). Annual mean streamflow for the 

Walloomsac River near North Bennington, Vt. (01334000), 

of 340 ft3/s is the second highest on record (fig. 12, in back of 

report) and is 150 percent of the period of record annual mean 

of 226 ft3/s.

St. Lawrence River Basin

Annual runoff for the St. Lawrence River Basin was 

recorded at 41streamgages. Annual runoff was generally 

greater than the 90th percentile; some subbasins had the 

highest annual runoff on record (fig. 4). For example, 

annual mean streamflows for Otter Creek at Middlebury, Vt. 

(04282500), Dog River at Northfield Falls, Vt. (04287000), 

and Missisquoi River near East Berkshire, Vt. (04293500), 

were the highest on record (figs. 13–15, in back of report) and 

were 184, 195, and 165 percent, respectively, of the period of 

record annual mean streamflows.
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 11

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Runoff, in inches

Date

A Computed Annual Runoff in New Hampshire

Water Year 2011

0

5

10

15

20

25

30

35

40

45

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Runoff, in inches

Date

B Computed Annual Runoff in Vermont

0

5

10

15

20

25

30

35

40

45

Water Year 2011

Figure 3. Computed annual runoff in A, New Hampshire and B, Vermont for 1901 to 2011. (From U.S. 

Geological Survey, 2011a).
12 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

Lowest < 10 10 - 24 25 - 75 76 - 90 >90 Highest No

data

EXPLANATION

New Hampshire Vermont

Annual runo, in percentile classes

Figure 4. Annual runoff for water year 2011, as a percentile of historical streamflow, 

by hydrologic cataloging units (HUC8) in New Hampshire and Vermont. (From U.S. 

Geological Survey, 2011b; <, less than; >, greater than).
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 13

Reservoir and Lake Elevations

The total combined usable storage of five major 

reservoirs in both States is 22,436 million cubic feet (ft3). 

Variations in month-end average usable capacity for the five 

major reservoirs are shown in figure 16. At the beginning of 

the water year, the actual usable storage from these reservoirs 

was 15,703 million ft3 or 70 percent of capacity. Average 

reservoir storage rose to 86 percent of capacity through 

October and was followed by a generally steady seasonal 

decline to a minimum capacity of 52 percent by the end of 

February, water year 2011. Average reservoir storage increased 

to a maximum of 96 percent through April and then generally 

declined. Month-end capacities for the five major reservoirs 

are available on the Internet at http://nh.water.usgs.gov/

WaterData/curr.htm.

Lake Champlain daily mean elevations for water year 

2011 and daily maximum, minimum, and average elevations 

for water years 1940 to 2010 are shown in figure 17. The 

annual mean elevation for water year 2011 was the highest for the period of record. All daily mean elevations for 

water year 2011 were greater than historical average daily 

mean elevations. Daily mean elevations in April, May, June, 

and September were greater than historical maximum daily 

mean elevations.

Groundwater Levels

The groundwater observation well network included 

41 wells—29 wells in New Hampshire and 12 wells in 

Vermont (table 2). Well locations are shown in figure 2 and are 

referenced by local well name (table 2). Month-end conditions 

are characterized in table 3 for the 38 wells with more than 

10 years of data. Water levels less than the 25th percentile 

are characterized as below normal, from the 25th to the 

75th percentile as normal, and above the 75th percentile as 

above normal.

Groundwater levels in New Hampshire were generally 

normal (table 3); however, many wells, such as NH–WCW 1 

(fig. 18), had above-normal levels for April, May, and 

September, coincident with flooding events. Groundwater levels in Vermont were generally normal to above normal. Most 

of the wells had above-normal levels for October, November, 

April, May, June, August, and September. Further information 

on groundwater conditions and the groundwater observation 

well network is available on the Internet at http://groundwaterwatch.usgs.gov/NHV/StateMaps/NH.html.

Floods

Record flooding occurred in April, May, and August 

of water year 2011. Peak-of-record streamflows occurred 

at 25 streamgages with more than 10 years of record. 

Flooding in April 2011 was widespread in parts of northern 

New Hampshire and Vermont. Flash flooding in May 2011 

was isolated to central and northeastern Vermont. Devastating 

flooding in August 2011 occurred throughout most of Vermont 

and in parts of New Hampshire as the result of the heavy rains 

associated with Tropical Storm Irene.

To gain a historical perspective on the relative magnitude 

of flood events in water year 2011, peak streamflows were 

ranked against previously recorded peaks of record (table 4). 

In water year 2011, many rivers in New Hampshire and 

Vermont reached historic levels. For example, the April 2011 

flood of the Lamoille River at East Georgia, Vt. (04292500), 

produced the largest streamflow in the 82-year period of 

record, whereas the August 2011 flood of the White River at 

West Hartford, Vt. (01144000), produced the largest streamflow since 1927 (table 4).

Annual peak streamflows recorded at streamgages 

during each flood event are shown relative to the contributing 

drainage area in figure 19. To gain perspective on the relative 

magnitude of the flood peaks, envelope lines for regional 

maximum flood streamflows (Crippen and Bue, 1977) and 

for maximum recorded flood streamflows in and adjacent to 

New Hampshire, as well as a regression line relating the 

100-year (Q100) streamflow to drainage area (Olson, 2008), 

have been included in figure 19.

Flood of April 26–29, 2011

The winter of 2010–11 produced an abnormally 

high snowpack in both New Hampshire and Vermont. In 

Burlington, Vt., the third highest total snowfall (128 in.) was 

recorded since records were established in 1893 (National 

Weather Service, 2011). This snowpack in conjunction with 

record rainfall in the months of April and May produced 

severe, widespread flooding in large basins within both States. 

The heaviest rainfall and resulting riverine flooding occurred 

April 26–29, 2011, across the Androscoggin, Connecticut, and 

St. Lawrence River Basins in northern New Hampshire and 

Vermont. The water level in Lake Champlain surpassed prior 

historical records and crested at 103.27 ft on May 6, 2011. 

Annual peak streamflows for water year 2011 were recorded 

at 29 streamgages (table 4). Peak-of-record streamflows 

were recorded at nine streamgages in the Connecticut and 

St. Lawrence River Basins.

Five streamgages in New Hampshire recorded stages 

at or above the flood stages designated by the National 

Weather Service. Minor to moderate flooding was reported 

in the Androscoggin, Pemigewasset, and the Connecticut 

River Basins. Flooding in Vermont was more widespread; 

10 streamgages or lake gages recorded stages at or above 

the flood stages designated by the National Weather Service. 

Minor to moderate flooding occurred in the Passumpsic, 

Otter Creek, and Winooski River Basins. Major flooding 

occurred in the Lamoille and Missisquoi River Basins, and at 

Lake Champlain.
14 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

First

Connecticut

Lake

Lake

Francis

Connecticut River

Merrimack River

Somerset

Reservoir

Harriman

Reservoir

Lake

Winnipesaukee

Atlantic

Ocean

Lake Champlain

0 50 MILES

0 50 KILOMETERS

MAINE

CANADA

NEW

YORK

MASSACHUSETTS

NEW HAMPSHIRE

VERMONT

72o

71o

73o

45o

44o

43o

Lake Francis First Connecticut Lake

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

0

20

40

60

80

100

120

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep 0

20

40

60

80

100

120

0

20

40

60

80

100

120

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

Lake Winnipesaukee

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

0

20

40

60

80

100

120

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

Somerset Reservoir

0

20

40

60

80

100

120

Harriman Reservoir

Percent full at end of month

Percent full at end of month

Percent full at end of month

Percent full at end of month

Percent full at end of month

Water Year 2011 Water Year 2011

Water Year 2011

Water Year 2011 Water Year 2011

Figure 16. Locations of selected lakes or reservoirs in New Hampshire and Vermont and corresponding month-end 

contents, water year 2011.
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 15

94

94.5

95

95.5

96

96.5

97

97.5

98

98.5

1940 1950 1960 1970 1980 1990 2000 2010

92

94

96

98

100

102

104

A

B

Daily mean elevation above NGVD 29, in feet

04294500 Lake Champlain at Burlington, VT

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

Annual mean elevation above NGVD 29, in feet

Water Year

75th percentile

50th percentile

25th percentile

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Figure 17. A, Daily mean surface-water elevation at station 04294500 Lake Champlain at 

Burlington, Vermont, water year 2011, and daily maximum, minimum, and average elevations 

for water years 1940–2010 and B, annual mean elevations for water years 1940–2011, and the 

25th, 50th, and 75th percentiles.
16 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

Table 3. Month-end groundwater-level conditions for 38 wells in New Hampshire and Vermont, water year 2011.

[Month-end groundwater levels were measured in 38 long-term wells completed in unconsolidated material. Conditions are in relation to the period of record for 

each well. Conditions: N, normal, within the 25th to 75th percentile range of record for the month; -, below normal, within the lowest 25th percentile of record 

for the month; +, above normal, within the highest 25th percentile of record for the month. See figure 2 for well locations. Prefixes NH and VT have been omitted from the well names. NH, New Hampshire; VT, Vermont; --, no data]

Water Year 2011

NH groundwater wells 

(Town) COUNTY OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEP

BAW-10 (BARNSTEAD) Belknap N N - N N N N N N N N -

ADW-14 (ALBANY) Carroll N N + - - N + + N - N +

ADW-15 (ALBANY) Carroll N N + - - N + + N - N +

OXW-38 (OSSIPEE) Carroll N N N N N N + N N N N +

KEW-2 (KEENE) Cheshire + N N + + N + + + + + +

CTW-73 (COLEBROOK) Coos N N N N N N N N N N N N

ETW-1 (ERROL) Coos N N - - - N - N - N N N

LCW-1 (LANCASTER) Coos -- N N + -- N + N -- N -- --

SJW-2 (SHELBURNE) Coos - N N - - N - N - - - -

CBW-34 (CAMPTON) Grafton N N N - - + + + N - N +

ENW-30 (ENFIELD) Grafton N N N N -- -- + N N -- -- -

LLW-19 (LISBON) Grafton N N N + + + N + N - - +

GSW-75 (GREENFIELD) Hillsborough N N N - - N N - N N N N

NAW-218 (NASHUA) Hillsborough N N N N N + N N N N N N

CVW-2 (CONCORD) Merrimack + + + + + + + + + + + +

CVW-4 (CONCORD) Merrimack - - N - - N N N N N N +

FKW-1 (FRANKLIN) Merrimack - - - - - N N N N N N +

HTW-5 (HOOKSETT) Merrimack - - - - - + N N N N N +

NLW-1 (NEW LONDON) Merrimack N + + N N + + + + + + +

WCW-1 (WARNER) Merrimack N N N N N + -- -- + -- + +

DDW-46 (DEERFIELD) Rockingham - - N - - N N + N N N N

EPW 90 (EPPING) Rockingham -- -- -- -- -- -- -- -- -- -- -- --

LIW-1 (LEE) Strafford N + + N -- -- + + + -- -- --

NFW-53 (NEW DURHAM) Strafford N N + N N + N + N + N +

NPW-3 (NEWPORT) Sullivan N N N - - + N + N - N +

NPW-6 (NEWPORT) Sullivan N N N - - N N N N - N +

VT groundwater wells 

(Town) COUNTY OCT NOV DEC JAN FEB MAR APR MAY JUNE JULY AUG SEP

MGW-11 (MIDDLEBURY) Addison + N - N N N N N N N + +

PQW-1 (POWNAL) Bennington + + + N N + + + N N + +

MJW-3 (MILTON) Chittenden + + + + + + + + + -- + +

BIW-1 (BRIGHTON) Essex + + + + + + + + + + N -

MPW-1 (MORRISTOWN) Lamoille + + N N N N + + + + + +

WOW-1 (WEST FAIRLEE) Orange + + + N N N + + + N + +

GLW-1 (GLOVER) Orleans + + + + + N + + + N + +

PFW-8 (PITTSFORD) Rutland + + + + + + + + + + + +

WAW-2 (WAITSFIELD) Washington + N N N N N + + + N + +

CKW-1 (CHESTER) Windsor + + + - - N + + + N + +

HLW-54 (HARTLAND) Windsor N N N N N N + + + N + +

RJW-1 (ROCHESTER) Windsor + N N N N N N N + N -- +
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 17

Water Year 2011

25

26

27

28

29

30

31

32

33

34

35

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

Depth to water level, in feet below land surface

Explanation

 25th percentile monthly median

 Highest monthly median

 Lowest monthly median

 75th percentile monthly median

 Daily mean

Figure 18. Daily mean depths to water in groundwater well 431500714528011, NH-WCW1, Town of Warner, New Hampshire, 

water year 2011, in relation to the distribution of monthly mean depths to water, water years 1965–2010.
18 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 Table 4. Peak stages and streamflows for selected New Hampshire and Vermont streamgages during record flooding in April, May, and August, water year 2011, and historical peak streamflows.—Continued [mi2, square miles; ft, foot; ft3/s, cubic feet per second; NH, New Hampshire; VT, Vermont] Station number Station name Drainage area (mi2

)

Annual data for Water Year 2011 Historical data

Date

Peak 

stage 

(ft)

Peak 

streamflow 

(ft3/s)

Ranka Number of years Year Peak streamflow (ft3/s)

Flood of April 26–29, 2011

Androscoggin River Basin

01052500 DIAMOND RIVER NEAR WENTWORTH LOCATION, NH 152 4/27/2011 10.03 7,780 9 70 1998 12,800

Connecticut River Basin

01129200 CONNECTICUT R BELOW INDIAN STREAM NR PITTSBURG, NH 254 4/27/2011 8.85 6,550 1 55 2011 6,55001129420 CAPON BROOK AT VT 102, NEAR CANAAN, VT 4.71 4/27/2011 10.67 423 1 5 2011 42301129500 CONNECTICUT RIVER AT NORTH STRATFORD, NH 799 4/27/2011 14.90 29,500 2 81 1998 32,30001130000 UPPER AMMONOOSUC RIVER NEAR GROVETON, NH 232 4/28/2011 7.52 6,940 12 65 1969 24,10001131500 CONNECTICUT RIVER NEAR DALTON, NH 1,514 4/29/2011 22.07 33,200 8 84 1936 48,30001138500 CONNECTICUT RIVER AT WELLS RIVER, VT 2,644 4/29/2011 13.58 47,200 6 62 1973 57,100

St. Lawrence River Basin

04282700 LEWIS CREEK TRIBUTARY AT STARKSBORO, VT 5.31 4/27/2011 23.34 598 4 25 1974 1,35004282780 LEWIS CREEK AT NORTH FERRISBURG, VT. 77.2 4/27/2011 6.04 4,690 1 22 2011 4,69004282795 LAPLATTE RIVER AT SHELBURNE FALLS, VT. 44.6 4/27/2011 6.82 2,120 3 22 1996 2,64004282813 POTASH BR @ QUEEN CITY PARK RD, NR BURLINGTON, VT 7.18 4/27/2011 5.34 634 1 7 2011 63404288225 W BRANCH LITTLE R ABV BINGHAM FALLS NEAR STOWE, VT 4.67 4/27/2011 4.92 1,430 2 11 2010 1,74004288230 RANCH BROOK AT RANCH CAMP, NEAR STOWE, VT 3.80 4/27/2011 4.47 983 2 11 2010 1,13004288400 BRYANT BROOK AT WATERBURY CENTER, VT 2.64 4/27/2011 12.98 223 3 25 1973 30204289000 LITTLE RIVER NEAR WATERBURY, VT 111 4/27/2011 16.35 5,240 2 76 1936 6,52004289600 WINOOSKI RIVER TRIBUTARY NEAR RICHMOND, VT 0.71 4/27/2011 14.28 85 2 24 1972 10204290335 ALLEN BROOK AT VT 2A, NEAR ESSEX JUNCTION, VT 9.9 4/27/2011 6.42 2,350 1 6 2011 2,35004290700 BAILEY BROOK AT EAST HARDWICK, VT 2.52 4/27/2011 14.57 219 3 28 1973 28504292000 LAMOILLE RIVER AT JOHNSON, VT 310 4/27/2011 16.97 13,800 3 85 1995 19,00004292100 STONY BROOK NEAR EDEN, VT 4.21 4/27/2011 13.38 611 3 23 1973 89004292500 LAMOILLE RIVER AT EAST GEORGIA, VT 686 4/27/2011 13.10 28,800 1 82 2011 28,80004292770 STEVENS BROOK AT LEMNAH DRIVE, AT ST ALBANS, VT 1.54 4/26/2011 3.54 297 1 5 2011 29704292810 JEWETT BROOK AT VT 38, NEAR ST. ALBANS, VT 3.74 4/28/2011 6.74 416 1 3 2011 41604293800 MISSISIQUOI RIVER TRIBUTARY AT SHELDON JUNCTION, VT 1.69 4/27/2011 14.84 104 3 29 2002 12204293900 HUNGERFORD BR @ HIGHGATE RD NR HIGHGATE CENTER, VT 18.6 4/27/2011 6.02 1,360 1 2 2011 1,360
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 19

Table 4. Peak stages and streamflows for selected New Hampshire and Vermont streamgages during record flooding in April, May, and August, water year 2011, and historical peak streamflows.—Continued[mi2, square miles; ft, foot; ft3/s, cubic feet per second; NH, New Hampshire; VT, Vermont]

Station 

number Station name

Drainage 

area 

(mi2

)

Annual data for Water Year 2011 Historical data

Date

Peak 

stage 

(ft)

Peak 

streamflow 

(ft3/s)

Ranka Number of years Year Peak streamflow (ft3/s)

Flood of April 26–29, 2011—Continued

St. Lawrence River Basin—Continued

04294000 MISSISQUOI RIVER AT SWANTON, VT 850 4/28/2011 7.49 25,500 6 22 1996 37,70004294300 PIKE RIVER AT EAST FRANKLIN, NR ENOSBURG FALLS, VT 34.5 4/27/2011 6.23 2,400 2 10 2006 3,01004296300 PHERRINS RIVER TRIBUTARY NEAR ISLAND POND, VT 1.05 4/27/2011 12.78 80 3 28 1969 14004296500 CLYDE RIVER AT NEWPORT, VT 142 4/28/2011 9.37 3,820 2 95 1936 3,900

Flood of May 27, 2011

Connecticut River Basin

01134800 KIRBY BROOK AT CONCORD, VT 8.05 5/27/2011 17.57 1,640 1 24 2011 1,64001135150 POPE BROOK (SITE W-3) NEAR NORTH DANVILLE, VT 3.25 5/27/2011 5.34 549 1 21 2011 54901135300 SLEEPERS RIVER (SITE W-5) NEAR ST. JOHNSBURY, VT 42.9 5/27/2011 8.56 9,360 1 21 2011 9,36001135500 PASSUMPSIC RIVER AT PASSUMPSIC, VT 436 5/27/2011 18.92 13,800 4 84 1973 18,20001135700 JOES BROOK TRIBUTARY NEAR EAST BARNET, VT 0.76 5/27/2011 18.63 324 1 23 2011 324

St. Lawrence River Basin

04292355 MORGAN BR TRIB AT OLD NO 11 RD, NEAR WESTFORD, VT 2.15 5/27/2011 12.23 292 1 5 2011 292

Flood of August 28–September 2, 2011

Saco River Basin

010642505 SACO RIVER AT RIVER STREET, AT BARTLETT, NH 91 8/28/2011 14.83 29,100 1 2 2011 29,10001064500 SACO RIVER NEAR CONWAY, NH 385 8/28/2011 17.23 58,200 1 88 2011 58,20001064801 BEARCAMP RIVER AT SOUTH TAMWORTH, NH 67.6 8/28/2011 9.35 5,640 2 19 1998 6,150

Merrimack River Basin

01074520 EAST BRANCH PEMIGEWASSET RIVER AT LINCOLN, NH 115 8/28/2011 17.50 29,300 1 19 2011 29,30001075000 PEMIGEWASSET RIVER AT WOODSTOCK, NH 193 8/28/2011 16.97 53,700 1 67 2011 53,70001076000 BAKER RIVER NEAR RUMNEY, NH 143 8/28/2011 13.99 11,300 9 77 1927 25,90001076500 PEMIGEWASSET RIVER AT PLYMOUTH, NH 622 8/29/2011 21.38 41,100 9 108 1936 65,40001077400 COCKERMOUTH RIVER BELOW HARDY BROOK, AT GROTON, NH 21.4 8/28/2011 11.17 5,260 1 3 2011 5,260
20 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 Table 4. Peak stages and streamflows for selected New Hampshire and Vermont streamgages during record flooding in April, May, and August, water year 2011, and historical peak streamflows.—Continued [mi2, square miles; ft, foot; ft3/s, cubic feet per second; NH, New Hampshire; VT, Vermont] Station number Station name Drainage area (mi2

)

Annual data for Water Year 2011 Historical data

Date

Peak 

stage 

(ft)

Peak 

streamflow 

(ft3/s)

Ranka Number of years Year Peak streamflow (ft3/s)

Flood of August 28–September 2, 2011—Continued

Connecticut River Basin

01133000 EAST BRANCH PASSUMPSIC RIVER NEAR EAST HAVEN, VT 53.8 8/28/2011 9.79 3,250 3 52 1973 4,45001137500 AMMONOOSUC RIVER AT BETHLEHEM JUNCTION, NH 87.6 8/28/2011 10.90 8,600 6 72 1995 11,30001139000 WELLS RIVER AT WELLS RIVER, VT 98.4 8/28/2011 9.03 5,170 2 71 1973 5,97001139700 WAITS RIVER TRIBUTARY NEAR WEST TOPSHAM, VT 1.09 8/28/2011 11.95 146 1 22 2011 14601139800 EAST ORANGE BRANCH AT EAST ORANGE, VT 8.95 8/28/2011 5.14 719 2 53 1990 80001142400 THIRD BRANCH WHITE RIVER TRIBUTARY AT RANDOLPH, VT 0.77 8/28/2011 12.55 117 4 25 1998 32701142500 AYERS BROOK AT RANDOLPH, VT 30.5 8/28/2011 15.04 3,920 1 72 2011 3,92001144000 WHITE RIVER AT WEST HARTFORD, VT 690 8/29/2011 28.36 90,100 2 96 1927 120,00001144500 CONNECTICUT RIVER AT WEST LEBANON, NH 4,092 8/29/2011 29.66 105,000 4 98 1927 136,00001150800 KENT BROOK NEAR KILLINGTON, VT 3.31 8/28/2011 15.70 2,840 1 24 2011 2,84001151200 OTTAUQUECHEE RIVET TRIBUTARY NEAR QUECHEE, VT 0.82 8/28/2011 11.73 59 2 22 1973 9301153300 MIDDLE BRANCH WILLIAMS RIVER TRIBUTARY AT CHESTER, VT 3.16 8/28/2011 21.65 602 1 26 2011 60201153550 WILLIAMS RIVER NEAR ROCKINGHAM VT 112 8/28/2011 17.94 21,300 1 25 2011 21,30001154000 SAXTONS RIVER AT SAXTONS RIVER, VT 72.2 8/28/2011 19.58 21,600 1 53 2011 21,60001154500 CONNECTICUT RIVER AT NORTH WALPOLE, NH 5,493 8/29/2011 31.38 99,700 1 70 2011 99,70001156300 WHETSTONE BROOK TRIBUTARY NEAR MARLBORO, VT 1.05 8/28/2011 22.36 762 1 24 2011 76201157000 ASHUELOT RIVER NEAR GILSUM, NH 71.1 8/28/2011 8.18 2,300 13 62 2006 10,200

Hudson River Basin

01334000 WALLOOMSAC RIVER NEAR NORTH BENNINGTON, VT 111 8/28/2011 12.82 9,420 1 80 2011 9,420

St. Lawrence River Basin

04280000 POULTNEY RIVER BELOW FAIR HAVEN, VT 187 8/29/2011 23.28 12,800 2 83 1945 14,80004280240 METTAWEE RIVER TRIBUTARY NO. 3 AT VT 30, AT EAST RUPERT, VT 2.59 8/28/2011 15.01 220 1 5 2011 22004282000 OTTER CREEK AT CENTER RUTLAND, VT 307 8/29/2011 17.43 15,700 1 83 2011 15,70004282300 BRANDY BROOK AT BREAD LOAF, VT 2.24 8/28/2011 12.84 306 3 27 2000 54604282500 OTTER CREEK AT MIDDLEBURY, VT 628 9/2/2011 7.34 6,180 15 96 1927 13,60004282525 NEW HAVEN RIVER @ BROOKSVILLE, NR MIDDLEBURY, VT 115 8/28/2011 12.95 16,700 2 21 1998 21,70004286000 WINOOSKI RIVER AT MONTPELIER, VT 397 8/28/2011 19.05 14,600 4 96 1927 57,000
Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011 21

Table 4. Peak stages and streamflows for selected New Hampshire and Vermont streamgages during record flooding in April, May, and August, water year 2011, and historical peak streamflows.—Continued[mi2, square miles; ft, foot; ft3/s, cubic feet per second; NH, New Hampshire; VT, Vermont]

Station 

number Station name

Drainage 

area 

(mi2

)

Annual data for Water Year 2011 Historical data

Date

Peak 

stage 

(ft)

Peak 

streamflow 

(ft3/s)

Ranka Number of years Year Peak streamflow (ft3/s)

Flood of August 28–September 2, 2011—Continued

St. Lawrence River Basin—Continued

04287000 DOG RIVER AT NORTHFIELD FALLS, VT 76.1 8/28/2011 17.26 22,200 1 77 2011 22,20004287300 SUNNY BROOK NEAR MONTPELIER, VT 2.31 8/28/2011 7.71 317 4 24 1973 34204288000 MAD RIVER NEAR MORETOWN, VT 139 8/28/2011 19.26 24,200 1 84 2011 24,20004290500 WINOOSKI RIVER NEAR ESSEX JUNCTION, VT 1,044 8/29/2011 22.18 35,000 3 84 1927 113,00004293000 MISSISQUOI RIVER NEAR NORTH TROY, VT 131 8/29/2011 13.93 10,900 2 80 2002 11,50004293005 DUNN BROOK AT VT 100, NEAR NEWPORT CENTER, VT 2.85 8/28/2011 18.33 574 1 5 2011 57404293200 MUD CREEK AT BEAR MOUNTAIN RD, NEAR NORTH TROY, VT 37.1 8/28/2011 8.19 3,240 1 2 2011 3,24004293430 NORTH BRANCH ABOVE RIVER STREET, AT RICHFORD, VT 64.8 8/29/2011 13.66 3,000 1 2 2011 3,00004293500 MISSISQUOI RIVER NEAR EAST BERKSHIRE, VT 479 8/29/2011 14.12 14,700 9 95 1927 45,00004293600 TROUT RIVER AT HOPKINS BR, NR ENOSBURG FALLS, VT 78.6 8/28/2011 15.96 10,500 1 2 2011 10,50004296000 BLACK RIVER AT COVENTRY, VT 122 8/29/2011 8.20 4,070 1 60 2011 4,07004296150 LORD BROOK NEAR EVANSVILLE, VT 4.76 8/28/2011 15.54 429 1 28 2011 429

aRank of the maximum instantaneous peak streamflow measured during water year 2011 compared to historic annual peaks.
22 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

0.1 1 10 100 1,000 10,000

Drainage area, in square miles

10

100

1,000

10,000

100,000

1,000,000

Streamflow, in cubic feet per second

Annual peak streamflows at streamgages

in New Hampshire and Vermont recorded

in April 2011

Envelope line for maximum recorded

flood discharges at streamgages in 

and adjacent to New Hampshire (Olson, 2008)

Regional envelope line for 

maximum flood discharges

(Crippen and Bue, 1977)

Q100 = 219A0.800

EXPLANATION

Annual peak streamflows at streamgages 

in New Hampshire and Vermont recorded

in May 2011

Annual peak streamflows at streamgages 

in New Hampshire and Vermont recorded

in August 2011

Figure 19. Annual peak streamflows at selected streamgages in New Hampshire and Vermont, water year 

2011, in relation to the contributing drainage area, with envelope lines and a regression line relating the 

100-year streamflow to drainage area (From Olson, 2008; Q100, 100-year streamflow).
Summary 23

Flood of May 27, 2011

Flash flooding occurred on May 27, 2011, as a result of 

rainfall on already saturated soils. Localized riverine flooding 

occurred mainly in subbasins within the Connecticut River 

Basin in northeastern Vermont and was the result of severe 

thunderstorms and locally heavy rains of as much as 3 to 5 in. 

Annual peak streamflows for water year 2011 were recorded 

at six streamgages. Peak-of-record streamflows were recorded 

at five streamgages in the Connecticut and St. Lawrence River 

Basins (table 4).

Seven streamgages or lake gages recorded stages 

at or above the flood stages designated by the National 

Weather Service. Minor to moderate flooding occurred on 

the Androscoggin, Passumpsic, and Wells River Basins. 

Major flooding occurred in the Winooski River Basin and at 

Lake Champlain.

Lake Champlain

Record flooding occurred on Lake Champlain during 

the spring of 2011. Lake Champlain was above the National 

Weather Service flood stage of 100 ft for a 68-day period 

that spanned from April 13 to June 19, 2011 (fig. 17). Lake 

Champlain at Burlington, Vt. (04294500), was above the 

major flood level of 101.5 ft for 43 of the 68 days and peaked 

at 103.27 ft on May 6, 2011. This surpassed the maximum 

known elevation since at least 1827 of 102.1 ft, which 

occurred on May 4, 1869 (U.S. Geological Survey 2012). 

Flood of August 28 to September 2, 2011

Widespread riverine flooding occurred August 28 to 

September 2, 2011, across the Saco, Merrimack, Connecticut, 

Hudson, and St. Lawrence River Basins as the result of heavy 

rains associated with Tropical Storm Irene. Rainfall ranged 

from 4 to 7 in. in less than 12 hours. Annual peak streamflows 

for water year 2011 were recorded at 53 streamgages. Peakof-record streamflows were recorded at 24 streamgages in the 

Saco, Merrimack, Connecticut, Hudson, and St. Lawrence 

River Basins (table 4). Peak-of-record streamflows recorded at 

Kent Brook near Killington, Vt. (01150800), and Whetstone 

Brook Tributary near Marlboro, Vt. (01156300), resulted in 

runoff of 858 and 762 cubic feet per square mile, respectively, 

which were greater than the envelope line for maximum 

recorded flood streamflows at streamgages in and adjacent to 

New Hampshire (fig. 19).

Twelve streamgages in New Hampshire recorded stages 

at or above the flood stages designated by the National 

Weather Service. Minor to moderate flooding was reported in 

the Androscoggin, Saco, Baker, Smith, Warner, Suncook, and 

Ammonoosuc River Basins. Major flooding was reported in 

the Pemigewasset and the Connecticut River Basins. Eighteen 

streamgages in Vermont recorded stages at or above the flood 

stages designated by the National Weather Service. Minor to 

moderate flooding occurred in the Passumpsic, Poultney, and 

Black River Basins. Major flooding occurred in the Wells, 

Ayers, White, Williams, Walloomsac, Otter Creek, Winooski, 

Dog, Mad, Lamoille, and Missisquoi River Basins.

Summary

Record-high hydrologic conditions in New Hampshire 

and Vermont occurred during water year 2011 as characterized 

by 125 streamgages and lake gaging stations, 27 crest-stage 

gages, and 41 groundwater wells. This report summarizes 

hydrologic conditions in New Hampshire and Vermont for 

water year 2011 in terms of precipitation, streamflow, lake and 

reservoir elevations, and groundwater levels.

Computed annual runoff for water year 2011 was the 

sixth highest on record for New Hampshire and the highest 

on record for Vermont. Annual runoff was above normal 

and generally in the greater than 90th percentile in the 

Androscoggin, Saco, northern Merrimack, Connecticut, 

Hudson, and St. Lawrence River Basins. Annual runoff 

for some subbasins in the Connecticut and St. Lawrence 

River Basins was the highest ever recorded. In general, the 

Piscataquog River Basin experienced normal runoff in water 

year 2011.

At the beginning of the water year, the actual usable 

storage for First Connecticut Lake, Lake Francis, Somerset 

Reservoir, Harriman Reservoir, and Lake Winnipesaukee was 

70 percent of capacity. Average storage for the five reservoirs 

rose to 86 percent of capacity through October and was 

followed by a generally steady seasonal decline to a minimum 

capacity of 52 percent by the end of February. Average 

reservoir storage increased to a maximum of 96 percent 

through April and then generally declined. Lake Champlain 

annual mean elevation for water year 2011 was the highest 

for the period of record. All daily mean elevations for water 

year 2011 were greater than historical average daily mean 

elevations. Daily mean elevations for periods in April, May, 

June, and September were greater than historical maximum 

daily mean elevations.

Groundwater levels were generally normal in New 

Hampshire and normal to above normal in Vermont. Many 

wells in New Hampshire recorded above normal levels for 

April, May, and September, coincident with flooding events. 

The majority of wells in Vermont recorded above-normal 

levels for October, November, April, May, June, August, 

and September. 

Record flooding occurred in April, May, and August of 

water year 2011. Peak-of-record streamflows were recorded 

at 38 streamgages. Flooding in April 2011 was widespread 

in parts of northern New Hampshire and Vermont. Peak-ofrecord streamflows were recorded at nine streamgages. Flash 

flooding in May 2011 was isolated to central and northeastern 

Vermont. Peak-of-record streamflows were recorded at five 

streamgages. Record flooding occurred on Lake Champlain 
24 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

during the spring of 2011. Lake Champlain was above the 

National Weather Service flood stage for a 68-day period that 

spanned from April 13 to June 19, 2011. The peak elevation 

of 103.27 feet (ft) recorded on May 6, 2011, surpassed the 

maximum known elevation since at least 1827 of 102.1 ft. 

Devastating floods in August 2011 occurred throughout most 

of Vermont and in parts of New Hampshire as result of the 

heavy rains associated with Tropical Storm Irene. Rainfall 

ranged from 4 to 7 inches in less than 12 hours. Peak-of-record 

streamflows were recorded at 24 streamgages.

Acknowledgments

This report is the culmination of a concerted effort by 

dedicated personnel of the U.S. Geological Survey (USGS) 

who collected, processed, and compiled the data. The authors 

acknowledge the assistance provided by Robert Brown, 

Chandlee Keirstead, Glenn Berwick, Anthony Debonis, 

Heather Manzi, Kelsey-Ann Reagan, Celia Honigberg, and 

Cody Whelan in the collection of data. Thanks are extended to 

Philip Harte and Richard Verdi of the USGS for their technical 

reviews of this report. 

References Cited

Crippen, J.R., and Bue, C.D., 1977, Maximum flood flows in 

the conterminous United States: U.S. Geological Survey 

Water-Supply Paper 1887, 52 p.

National Oceanic and Atmospheric Administration, 2011, 

National Climatic Data Center, temperature and precipitation, accessed September 13, 2012, at http://www.ncdc.

noaa.gov/temp–and–precip/time–series.

National Weather Service, 2011, National Operational 

Hydrologic Remote Sensing Center National snow analyses, 

accessed September 13, 2012, at http://www.nohrsc.noaa.

gov/nsa/.

New Hampshire Department of Environmental Services, 2011, 

New Hampshire snow sampling sites, snow sampling data, 

accessed September 13, 2012, at http://www2.des.state.

nh.us/RTi_Home/snow_sampling_stations.asp.

Olson, S.A., 2008, Estimation of flood streamflows at selected 

recurrence intervals for streams in New Hampshire: U.S. 

Geological Survey Scientific Investigations Report 2008–

5206, 57 p.

U.S. Army Corps of Engineers, 2011, NEA Reservoir Regulation Section, New England District, NAE Snow Survey 

Bulletins, accessed September 13, 2012, at http://rsgisias.

crrel.usace.army.mil/nae/cwmsweb.cwmsindex.

U.S. Geological Survey, 2011a, WaterWatch Past Flow/

Runoff: U.S. Geological Survey Web interface, accessed 

August 24, 2012, at http://waterwatch.usgs.gov/index.

php?id=romap3&sid=w__graph.

U.S. Geological Survey, 2011b, WaterWatch Past Flow/

Runoff: U.S. Geological Survey Web interface, accessed 

August 24, 2012, at http://waterwatch.usgs.gov/index.

php?id=romap3&sid=w__map.

U.S. Geological Survey, 2012, Water-resources data for the 

United States, water year 2011: U.S. Geological Survey Water-Data Report WDR–US–2011, site 04295000, 

accessed January 25, 2012, at http://wdr.water.usgs.gov/

wy2011/pdfs/04295000.2011.pdf.
Figures 5–15
26 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

200

300

400

500

600

1940 1950 1960 1970 1980 1990 2000 2010

1

2

5

10

20

50

100

200

500

1,000

2,000

5,000

10,000

15,000 A

B

Daily streamflow, in cubic feet per second

01052500 Diamond River near Wentworth Location, NH

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

2011

75th percentile

25th percentile

50th percentile

Annual mean streamflow,

in cubic feet per second

Water Year

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Figure 5. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1941–2010 at station 01052500 Diamond River near 

Wentworth Location, New Hampshire, and B, annual mean streamflow for water years 

1941–2011, and 25th, 50th, and 75th percentiles for annual mean streamflows.
Figures 5–15 27

400

500

600

700

800

900

1,000

1,100

1,200

1,300

1,400

1,500

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

A

B

01064500 Saco River near Conway, NH

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

2011

75th percentile

25th percentile

50th percentile

Water Year

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,in cubic feet per second

Figure 6. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1904–10, 1929–2010 at station 01064500 Saco River near 

Conway, New Hampshire, and B, annual mean streamflow for water years 1904–10, 1929–2011, 

and 25th, 50th, and 75th percentiles for annual mean streamflows.
28 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

100

200

300

400

500

600

1930 1940 1950 1960 1970 1980 1990 2000 2010

0.1

0.4

1

4

10

40

100

400

1,000

4,000

10,000

A

B

01073500 Lamprey River near Newmarket, NH

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

2011

75th percentile

25th percentile

50th percentile

Water Year

2010

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 7. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1934–2010 at station 01073500 Lamprey River near 

Newmarket, New Hampshire, and B, annual mean streamflow for water years 1934–2011, and 

25th, 50th, and 75th percentiles for annual mean streamflows.
Figures 5–15 29

600

800

1,000

1,200

1,400

1,600

1,800

2,000

2,200

1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

80,000

A

B

01076500 Pemigewasset River at Plymouth, NH

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 8. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1904–2010 at station 01076500 Pemigewasset River at 

Plymouth, New Hampshire, and B, annual mean streamflow for water years 1904–2011, and 

25th, 50th, and 75th percentiles for annual mean streamflows.
30 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

11,000

1930 1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

100,000

A

B

01092000 Merrimack River near Goffs Falls, below Manchester, NH

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 9. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1937–2010 at station 01092000 Merrimack River near Goffs 

Falls, below Manchester, New Hampshire, and B, annual mean streamflow for water years 

1937–2011, and 25th, 50th, and 75th percentiles for annual mean streamflows. 
Figures 5–15 31

100

150

200

250

300

350

400

1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1,000

2,000

5,000

8,000

A

B

01137500 Ammonoosuc River at Bethlehem Junction, NH

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2010 2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 10. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and average streamflows for 

water years 1939–2010 at station 01137500 Ammonoosuc River at Bethlehem Junction, New Hampshire, and B, annual 

mean streamflow for water years 1939–2011, and 25th, 50th, and 75th percentiles for annual mean streamflows.
32 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

400

600

800

1,000

1,200

1,400

1,600

1,800

2,000

2,200

2,400

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

50,000

A

B

01144000 White River at West Hartford, VT

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 11. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, 

and average streamflows for water years 1916–2010 at station 01144000 White River at West 

Hartford, Vermont, and B, annual mean streamflow for water years 1916–2011, and 25th, 50th, 

and 75th percentiles for annual mean streamflows. 
Figures 5–15 33

80

120

160

200

240

280

320

360

400

1930 1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1000

2000

5000

8000

A

B

01334000 Walloomsac River near North Bennington, VT

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 12. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and average streamflows for 

water years 1931–2010 at station 01334000 Walloomsac River near North Bennington, Vermont, and B, annual mean 

streamflow for water years 1931–2011, and 25th, 50th, and 75th percentiles for annual mean streamflows.
34 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

300

500

700

900

1,100

1,300

1,500

1,700

1,900

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

Water Year

75th percentile

25th percentile

50th percentile

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

10

20

50

100

200

500

1,000

2,000

5,000

10,000

15,000

04282500 Otter Creek at Middlebury, VT

A

B

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 13. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1911–20 and 1929–2010 at station 04282500 Otter Creek at 

Middlebury, Vermont, and B, annual mean streamflow for water years 1911–20 and 1929–2011, 

and 25th, 50th, and 75th percentiles for annual mean streamflows.
Figures 5–15 35

50

100

150

200

250

300

1930 1940 1950 1960 1970 1980 1990 2000 2010

1

2

5

10

20

50

100

200

500

1,000

2,000

5,000

8,000

A

B

04287000 Dog River at Northfield Falls, VT

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 14. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1935–2010 at station 04287000 Dog River at Northfield 

Falls, Vermont, and B, annual mean streamflow for water years 1935–2011, and 25th, 50th, and 

75th percentiles for annual mean streamflows.
36 Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011

400

600

800

1,000

1,200

1,400

1,600

1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010

10

20

50

100

200

500

1,000

2,000

5,000

10,000

20,000

A

B

04293500 Missisquoi River near East Berkshire, VT

Oct Nov Dec Jan Feb Mar Apr May June July Aug Sep

75th percentile

25th percentile

50th percentile

Water Year

2011

Maximum 

Average 

Minimum

Water year 2011

EXPLANATION

Daily mean, water year 2011

2010

Daily streamflow, in cubic feet per second

Annual mean streamflow,

in cubic feet per second

Figure 15. A, Daily mean streamflow for water year 2011 and daily maximum, minimum, and 

average streamflows for water years 1917–19, 1922, 1923, and 1929–2010 at station 04293500 

Missisquoi River near East Berkshire, Vermont, and B, annual mean streamflow for water 

years 1917–19, 1922, 1923, and 1929–2011, and 25th, 50th, and 75th percentiles for annual mean 

streamflows.
Prepared by the Pembroke and West Trenton Publishing 

Service Centers.

For more information concerning this report, contact:

Office Chief

U.S. Geological Survey

New England Water Science Center

New Hampshire-Vermont Office

331 Commerce Way, Suite 2

Pembroke, NH 03275

dc_nh@usgs.gov

or visit our Web site at:

http://nh.water.usgs.gov
Kiah and others—Hydrologic Conditions in New Hampshire and Vermont, Water Year 2011—Open-File Report 2013–1135

Printed on recycled paper