Canada
United States
Belgium
France
Ireland
Netherlands
United Kingdom
Austria
Czechia
Germany
Poland
Slovenia
Switzerland
Italy
Spain
Türkiye
Denmark
Finland
Norway
SwedenMerrimack River at Nashua water level
River gauge, Merrimack River, New Hampshire, United States
Right now
Below flood stage
Water level
History
The forecast expects the river to fall to 4.50 ft by Wednesday, October 21 at 02:00 PM. Issued Tuesday, October 20 at 10:49 AM by NOAA National Weather Service.
What this means
Water levels are unremarkable at Merrimack River at Nashua, where the gauge shows 4.73 ft.
It is 13.27 ft below the flood stage of 18.00 ft.
It is still going down, by 0.21 ft over the past 24 hours. The forecast expects the river to fall to 4.50 ft by Wednesday, October 21 at 02:00 PM. The 30-day range is 4.68 ft – 5.10 ft.
Judged against the official flood stage for this gauge. How to read levels
Key numbers
- Highest on record
- 41.30 ftMarch 20, 1936
- Forecast peak
- 4.70 ftTuesday, October 20 at 08:00 PM
Paddling and fishing conditions
Most paddlers and anglers will find the river in good shape at this stage.
For reference, flood stage is 18.00 ft.
What happens at each level
- 40.00 ft
- This is a disastrous...life threatening flood. This compares to the Great New England Flood of 1936. Follow the advice of local officials...and evacuate if told to do so.
- 35.00 ft
- This is a major...life threatening flood event. The river has not reached this height since the Great New England flood of 1936. Major flooding will affect the communities of Merrimack and Litchfield through Nashua and Hudson. follow the advice of local officials...evacuate if told to do so. Stay away from the Merrimack River.
- 30.00 ft
- This flood compares to the Hurricane of 1938 flood. This is a substantial flood event. Follow the directions of local officials...evacuate if told to do so. At this height the Merrimack River is moving very swiftly. Stay away from the river.
- 28.00 ft
- The river has not reached this height since the Hurricane of 1938. This is a serious flood event. Follow the advice of local officials...evacuate if told to do so. At this height...the Merrimack River is moving very swiftly. Stay away from the river.
- 25.00 ft
- The river has not reached this height since May 2006. This is a significant flood event. Follow the advice of local officials...evacuate if told to do so.
- 21.00 ft
- Flooding will occur in low lying areas from Litchfield and Merrimack...to Hudson and Nashua.
- 18.00 ft
- Flooding will begin in the lower lying sections of Hudson and Nashua as the river continues to climb above 18 feet.
- 4.73 ft
- Right now
Impact statements from the U.S. National Weather Service.
Highest crests on record
| Rank | Level | Date |
|---|---|---|
| 1 | 41.30 ft | March 20, 1936 |
| 2 | 30.50 ft | September 23, 1938 |
| 3 | 26.00 ft | May 15, 2006 |
| 4 | 23.50 ft | April 17, 2007 |
| 5 | 22.40 ft | April 7, 1987 |
| 6 | 19.00 ft | April 18, 1996 |
| 7 | 18.81 ft | April 1, 2010 |
| 8 | 18.40 ft | March 28, 1953 |
| 9 | 18.10 ft | April 14, 1940 |
| 10 | 18.10 ft | October 22, 1996 |
Weather at the gauge
The forecast is not available right now.
Map
Other gauges on the Merrimack River
| Gauge | Level | Compared with normal | 24 hours | Distance |
|---|---|---|---|---|
| Merrimack River at Franklin JunctionRiver gauge, Merrimack River | 4.59 ft | Below flood stage | −0.18 ft | 47 mi |
| Merrimack River at ConcordRiver gauge, Merrimack River | 3.49 ft | Below flood stage | −0.63 ft | 31 mi |
| Merrimack River near Goffs Falls, below ManchesterRiver gauge, Merrimack River | 3.55 ft | Below flood stage | −0.17 ft | 13 mi |
| Merrimack River below Concord River at LowellRiver gauge, Merrimack River | 42.90 ft | Below flood stage | −0.25 ft | 11 mi |
| Merrimack River at LawrenceRiver gauge, Merrimack River | 10.59 ft | Normal | −0.49 ft | 15 mi |
| Merrimack River at NewburyportEstuary gauge, Merrimack River | −0.40 ft | Very low | +1.33 ft | 29 mi |
Nearby gauges
| Gauge | Level | Compared with normal | 24 hours | Distance |
|---|---|---|---|---|
| Beaver Brook at North PelhamRiver gauge, Beaver Brook | 21.5 cfs | Normal | −1.3 cfs | 4.7 mi |
| Souhegan River at MerrimackRiver gauge, Souhegan River | 2.81 ft | Below flood stage | −0.05 ft | 7 mi |
| Nashua River at East PepperellRiver gauge, Nashua River | 1.54 ft | Below flood stage | −0.44 ft | 9 mi |
| Concord River below R Meadow Brook, at LowellRiver gauge, Concord River | 4.57 ft | Below flood stage | −0.10 ft | 11 mi |
| Spicket River near MethuenRiver gauge, Spicket River | 4.30 ft | Below flood stage | +0.08 ft | 12 mi |
| Spicket River at North SalemRiver gauge, Spicket River | 81.0 cfs | Low | −3.9 cfs | 13 mi |
| Squannacook River near West GrotonRiver gauge, Squannacook River | 2.05 ft | Below flood stage | −0.07 ft | 14 mi |
| Souhegan River (Site Wlr-1) near MilfordRiver gauge, Souhegan River (Site Wlr-1) | 3.42 ft | Below flood stage | −0.30 ft | 14 mi |
Questions and answers
What is flood stage for the Merrimack River at Nashua?
The official flood stage is 18.00 ft. The level is currently 13.27 ft below it.
Is gage height the same as water depth?
No. Gage height is measured from a fixed reference point chosen by the agency, so a reading of 10 ft does not mean the river is 10 ft deep.
What is the water level of Merrimack River at Nashua today?
On Oct 20, 2026, 11:15 PM EDT, the water level was 4.73 ft. Down 0.21 ft over the last 24 hours.
Is Merrimack River at Nashua rising or falling?
Down 0.21 ft over the last 24 hours. Down 0.32 ft over the last 7 days.
Is the level of Merrimack River at Nashua normal?
Below flood stage. Judged against the official flood stage for this gauge.
What is the highest water level ever recorded at Merrimack River at Nashua?
The highest level on record is 41.30 ft on March 20, 1936.
Is Merrimack River at Nashua expected to rise?
The forecast expects the river to fall to 4.50 ft by Wednesday, October 21 at 02:00 PM.
For specialists
Station codes, datum, parameters, data quality and downloads
- Operator
- U.S. Geological Survey
- Station code
usgs:01096508(Agency page)- Coordinates
42.76342, -71.44284(WGS84)- Vertical datum
- NAVD88
- Update interval
- every 15 minutes
- Licence
- Public domain. Data: U.S. Geological Survey (USGS), provisional data subject to revision
Published series
| Parameter | Last value | Time (UTC) | Quality |
|---|---|---|---|
| Water level | 4.73 ft | 2026-10-21 03:15 | Provisional |
Download
Embed this gauge
Add a live card for this gauge to your website. It updates on its own and links back here.
How to cite
U.S. Geological Survey: Merrimack River at Nashua (usgs:01096508). Accessed October 21, 2026 via Nivelmap, https://nivelmap.com/en/united-states/new-hampshire/merrimack-river-at-nashua
How we check values
Each reading is stored as published. We hold back values that jump faster than physically plausible and show the measurement time with every value.
Readings are provisional, can be delayed or wrong and are not a flood warning. Read the disclaimer