National Weather Service Advanced Hydrologic Prediction Service

weather.gov

Home

News

Organization

Search by city or zip code. Press enter or select the go button to submit request

National Conditions
    Rivers
    Satellite
    Climate
    Observed Precip

Local Conditions
    Warnings
    Weather Forecast
    Radar

AHPS Documentation
User Guide
User Brochure

What is AHPS?
Facts
Our Partners

Feedback/Questions
    Provide Feedback
    Ask Questions

Web Portal Changes:

AHPS - water.weather.gov- Scheduled operations ends on Tuesday, May 28th, 2024
Please see water.noaa.gov/. Bookmark it NOW! The pages will automatically redirect to water.noaa.gov until May 28, 2025.
To go to a specific gauge location - use water.noaa.gov/gauges/NWSLI - where NWSLI is the five character ID of your favorite location.
Other Important URL changes - Service Change Notice 24-29

Please visit https://www.weather.gov/owp/operations for more information.

Weather Forecast Office Boston / Norton, MA

Northeast River Forecast Center

Hydrograph

River at a Glance

Download

Printable Image

About this graph

Tabular Data (UTC)

Tabular Data (EDT)

Datum: NAVD88

Metadata

NOTE: Forecasts for the Merrimack River at Lowell are issued routinely year-round.

Vertical datum height surveyed by the USGS

Return to Area Map

Upstream Gauge

Flood Categories (in feet)

Major Flood Stage:	58
Moderate Flood Stage:	54
Flood Stage:	52
Action Stage:	50
Low Stage (in feet):	-9999

Historic Crests
(1) 68.40 ft on 03/20/1936
(2) 60.60 ft on 04/23/1852
(3) 60.57 ft on 09/23/1938
(4) 58.84 ft on 05/15/2006
(5) 58.09 ft on 04/17/2007
Show More Historic Crests

(P): Preliminary values subject to further review.

Recent Crests
(1) 53.16 ft on 12/20/2023
(2) 54.64 ft on 04/01/2010
(3) 53.63 ft on 03/16/2010
(4) 58.09 ft on 04/17/2007
(5) 58.84 ft on 05/15/2006
Show More Recent Crests

(P): Preliminary values subject to further review.

Low Water Records
Currently none available.

For more information on your flood risk go to www.floodsmart.gov.

Show FEMA's National Flood Hazard Layers

Zoom Level:16

	Gauge Location	Disclaimer
Latitude/Longitude Disclaimer: The gauge location shown in the above map is the approximate location based on the latitude/longitude coordinates provided to the NWS by the gauge owner.

Flood Impacts & Photos

If you notice any errors in the below information, please contact our Webmaster
65	This is a serious flood event. All persons along the Merrimack River should follow the evacuation recommendations from your local emergency managemant officials. If asked to evacuate, do so immediately. All flood protection measures must be rushed to completion in flood prone areas.
62	This is a serious flood event. All persons along the Merrimack River should follow the evacuation recommendations from your local emergency managemant officials. If asked to evacuate, do so immediately. All flood protection measures must be rushed to completion in flood prone areas.
60	This is a serious flood event. All persons along the Merrimack River from the Massachusetts border through Methuen should follow the evacuation recommendations from your local emergency managemant officials. If asked to evacuate, do so immediately. All flood protection measures must be rushed to completion in flood prone areas.
58	Flooding is expected to overspread portions of Route 113 above Pawtucket Falls. Also, portions of Route 110 and several homes and businesses along Route 110 heading north and east into Tewksbury may begin to experience flooding. Follow the direction of your local emergency management officals. If asked to evacuate, do so immediately.
56	Flooding will become more widespread from the New Hampshire border through Methuen. Those areas outside local flood protection should take measures to protect property. Follow the directions of your local emergency management agency.
55	Flooding will become more widespread from the New Hampshire border through Methuen. Those areas outside local flood protection should take measures to protect property. Follow the directions of your local emergency management agency.
52	Lowland flooding is likely along the Merrimack River. Most of the impact will be felt by businesses and mills where basement flooding is likely.

About This Location

Latitude: 42.645925° N, Longitude: 71.298394° W, Horizontal Datum: NAD83/WGS84

River Stage Reference Frame	Gauge Height	Flood Stage	Uses
NWS stage	0 ft	52 ft	Interpreting hydrographs and NWS watch, warnings, and forecasts, and inundation maps
Vertical Datum	Elevation (gauge height = 0)	Elevation (gauge height = flood stage)	Elevation information source
NAVD88	4.37	56.37	Survey grade GPS equipment, FEMA flood plain maps, newer USGS topographic maps
NGVD 29	Not Available	Not Available	Older USGS topographic maps, NGVD29 benchmarks
MSL	Not Available	Not Available	Older USGS topographic maps, MSL benchmarks
Other	NULL	NULL

Current/Historical Observations:

U.S. Geological Survey (USGS) Data and Site Info for Lowell

Additional Information

Potential River Levels - Used to

Potential River Levels Used to Estimate the Chance of Flooding and the Range of Possible River Levels
10 Day (HEFS)	7 Day (NAEFS)	7 Day (GEFS)

Note: Use the official hydrograph at the top of this web page for river levels within the next 72 hours.

Click individual graphics to enlarge.

Resources

Hydrologic Resources

Additional Resources

Collaborative Agencies

The National Weather Service prepares its forecasts and other services in collaboration with agencies like the US Geological Survey, US Bureau of Reclamation, US Army Corps of Engineers, Natural Resource Conservation Service, National Park Service, ALERT Users Group, Bureau of Indian Affairs, and many state and local emergency managers across the country. For details, please click here.

NWS Information

National Weather Service
Boston / Norton Weather Forecast Office
46 Commerce Way
Norton, MA 02766
(508) 622-3250
Ask Questions/Webmaster
Page last modified: 2-Nov-2020 7:30 PM

Disclaimer
Credits
Glossary