New Hampshire lake & reservoir water levels

7 lakes tracked · 3 with a current elevation reading · USGS Water Services + USACE CWMS Data

New Hampshire has 7 lakes and reservoirs tracked here — 3 with a current elevation reading, from USGS Water Services and USACE CWMS Data. Sort the table by level, storage, %-full, or trend, then open any lake for its full elevation-with-datum, trend sparkline, storage, and source-and-vintage stamp. Figures are provisional readings for reference — not for navigation or safety decisions.

Statewide totals New Hampshire · USGS + USACE
Lakes tracked
7

3 report a current pool-elevation reading; the rest report storage only.

With elevation reading
3
With %-full figure
0

All New Hampshire lakes

Every lake tracked in New Hampshire. Click a column heading to sort, or filter by name. Elevation lakes are listed before storage-only lakes; a missing figure always shows "not reported," never an estimate.

New Hampshire lakes, elevation lakes first, by name.
Datum Trend
Franklin Falls Dam 306.90 NGVD29 1 ↓Falling
Otter Brook Dam 702.21 NGVD29 91 ↓Falling
Surry Mountain Dam 491.39 NGVD29 0 →Steady
Blackwater Dam 5
Edward Macdowell Dam 89
Everett Dam 979
Hopkinton Dam 100

Data: USGS Water Services (waterservices.usgs.gov) and USACE CWMS Data (cwms-data.usace.army.mil), retrieved 2026-08-31. Both public domain (a work of the U.S. Government, 17 U.S.C. §105).

Every New Hampshire lake in detail

Each lake tracked in New Hampshire has its full record here — current reading, recent trend, and the dam behind it where the National Inventory of Dams has one. Use the table above to jump to a lake, or read straight through.

Franklin Falls Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
306.90 ft

Datum NGVD29

% of conservation pool full
Not reported
Storage
1 acre-ft
Recent trend
↓Falling

−5.0 ft over the trend window

312.2ft307.1ftJun 2 – Jun 7

Franklin Falls Dam is held back by Franklin Falls Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 116 ft high and running 1,740 ft along its crest , built across PEMIGEWASSET RIVER in Merrimack County , near FRANKLIN . It was completed in 1943 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00003 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/FFD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Franklin Falls Dam →

Otter Brook Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
702.21 ft

Datum NGVD29

% of conservation pool full
Not reported
Storage
91 acre-ft
Recent trend
↓Falling

−0.3 ft over the trend window

703.1ft702.8ftJun 2 – Jun 7

Otter Brook Dam is held back by Otter Brook Dam , a concrete gravity structure, resisting the reservoir by its own weight alone , standing 119 ft high and running 1,288 ft along its crest , built across OTTER BROOK in Cheshire County , near KEENE . It was completed in 1958 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00006 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/OBD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Otter Brook Dam →

Surry Mountain Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
491.39 ft

Datum NGVD29

% of conservation pool full
Not reported
Storage
0 acre-ft
Recent trend
→Steady

0.0 ft over the trend window

491.4ft491.4ftJun 2 – Jun 7

Surry Mountain Dam is held back by Surry Mountain Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 83 ft high and running 1,800 ft along its crest , built across ASHUELOT RIVER in Cheshire County , near SURRY . It was completed in 1941 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00007 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/SMD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Surry Mountain Dam →

Blackwater Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
Not reported
% of conservation pool full
Not reported
Storage
5 acre-ft
Recent trend
Not enough recent readings

Blackwater Dam is held back by Blackwater Dam , a concrete gravity structure, resisting the reservoir by its own weight alone , standing 75 ft high and running 1,150 ft along its crest , built across BLACKWATER RIVER in Merrimack County , near WEBSTER . It was completed in 1941 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00001 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/BWD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Blackwater Dam →

Edward Macdowell Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
Not reported
% of conservation pool full
Not reported
Storage
89 acre-ft
Recent trend
Not enough recent readings

Edward Macdowell Dam is held back by Edward MacDowell Dam , an earthfill embankment, holding the pool back by sheer mass and an impervious core rather than by the strength of concrete , standing 63 ft high and running 1,100 ft along its crest , built across NUBANUSIT BROOK in Hillsborough County , near PETERBOROUGH . It was completed in 1950 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00005 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/EMD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Edward Macdowell Dam →

Everett Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
Not reported
% of conservation pool full
Not reported
Storage
979 acre-ft
Recent trend
Not enough recent readings

Everett Dam is held back by Everett Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 115 ft high and running 2,000 ft along its crest , built across PISCATAQUQG RIVER in Hillsborough County , near GOFFSTOWN . It was completed in 1961 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00002 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/EVD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Everett Dam →

Hopkinton Dam

USACE · reading Aug 22, 2026, 1:15 PM (UTC+00:00)

Pool elevation
Not reported
% of conservation pool full
Not reported
Storage
100 acre-ft
Recent trend
Not enough recent readings

Hopkinton Dam is held back by Hopkinton Dam , a rockfill embankment — quarried rock placed in compacted layers around a sealing core , standing 71 ft high and running 790 ft along its crest , built across CONTOOCOOK RIVER in Merrimack County , near WEST HOPKINTON . It was completed in 1962 , and is owned by USACE - New England District , to a design credited to CENAE. Its recorded primary purpose is flood risk reduction — the pool is drawn down between storms so there is empty space waiting for the next flood, which is why this level can fall in dry weather and climb sharply after rain. Its spillway is ungated: once the pool reaches the crest, water leaves on its own and the operator cannot hold it back. NID classes it high hazard potential. That describes what a failure would cost downstream — loss of life would be expected — and says nothing about how likely a failure is, or what condition the dam is in. National Inventory of Dams record NH00004 — U.S. Army Corps of Engineers, public domain.

Source: USACE NAE/HKD, retrieved Aug 31, 2026, 8:24 AM (UTC+00:00). Official page for Hopkinton Dam →

Frequently asked questions

How many lakes and reservoirs in New Hampshire are tracked here?
7, of which 3 report a current pool-elevation reading. The rest report storage only, or lack a fresh reading and are not published.
Which New Hampshire lakes report a %-full figure?
None of New Hampshire's lakes in this dataset currently have a source-provided %-full figure — we show the bare level rather than estimate one.
Where does the data come from?
USGS Water Services and USACE CWMS Data, both public domain. See the methodology page for the exact endpoints and update cadence.

Explore

Read the methodology behind these figures, or search all lakes nationally from the home page.