Merrimack River at Concord
Future / Actual / Minor
OWP 2.0 WWA Modal Title
01/11/2021, 10:04 PM UTC through 01/11/2021, 10:04 PM UTC
Sender
Sent
- Upstream gauge unavailableDownstream gauge unavailableWarning: no valid ratings curve available. Transformations to and from FEET/CFS/KCFS will not happen.
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Observed (OBS) 06/30/2025 1:30 AM EDTCATEGORY STAGE 
Major Flooding 20 ft Moderate Flooding 17 ft Minor Flooding 14 ft Action 12 ft Reliability of the Forecast:
NOTE: Forecasts are issued as needed during times of high water, but are not routinely available.
National Water Model Hydrograph
Official NWS streamflow forecasts are produced by NWS hydrologic forecasters for river gauge locations using hydrologic models which are calibrated to that location. This process considers additional guidance and information, including local expertise and experience, to produce the best forecast possible. The NWM output provides supplemental guidance to NWS forecasters and should not be considered an official NWS river forecast.
Flood Impacts
- 18 - Flooding occurs at businesses near the ice arena parking lot.
- 16 - The parking lot on the east bank downstream of the Route 9 bridge floods.
- 14 - Lowland flooding occurs.
Gauge Location
Recent Crests
| 1. | 15.12 ft | on 05-15-2006 |
| 2. | 11.86 ft | on 04-06-2005 |
| 3. | 12.53 ft | on 04-15-2004 |
| 4. | 11.31 ft | on 03-31-2003 |
| 5. | 12.37 ft | on 04-16-2002 |
Recent Crests
| 1. | 15.12 ft | on 05-15-2006 | |
| 2. | 11.86 ft | on 04-06-2005 | |
| 3. | 12.53 ft | on 04-15-2004 | |
| 4. | 11.31 ft | on 03-31-2003 | |
| 5. | 12.37 ft | on 04-16-2002 | |
| 6. | 12.67 ft | on 04-25-2001 | |
| 7. | 12.34 ft | on 04-11-2000 | |
| 8. | 13.28 ft | on 09-18-1999 | |
| 9. | 13.63 ft | on 03-31-1998 | |
| 10. | 12.80 ft | on 04-20-1997 | |
| 11. | 12.55 ft | on 04-15-1994 | |
| 12. | 12.41 ft | on 04-12-1993 | |
| 13. | 11.95 ft | on 10-08-1991 | |
| 14. | 11.51 ft | on 04-24-1991 | |
| 15. | 12.03 ft | on 05-08-1989 | |
| 16. | 12.41 ft | on 05-01-1988 | |
| 17. | 13.41 ft | on 03-03-1987 | |
| 18. | 11.84 ft | on 04-01-1986 | |
| 19. | 12.92 ft | on 05-31-1984 | |
| 20. | 11.86 ft | on 05-21-1983 | |
| 21. | 13.03 ft | on 12-23-1973 | |
| 22. | 14.28 ft | on 04-19-1969 | |
| 23. | 14.65 ft | on 04-06-1960 | 1 |
| 24. | 13.69 ft | on 03-28-1953 | |
| 25. | 14.40 ft | on 04-04-1951 | |
| 26. | 23.00 ft | on 09-22-1938 | |
| 27. | 26.20 ft | on 03-20-1936 | |
| 28. | 20.80 ft | on 11-05-1927 |
Historic Crests
| 1. | 26.20 ft | on 03-20-1936 | |
| 2. | 23.00 ft | on 09-22-1938 | |
| 3. | 20.80 ft | on 11-05-1927 | |
| 4. | 15.12 ft | on 05-15-2006 | |
| 5. | 14.65 ft | on 04-06-1960 | 1 |
Historic Crests
| 1. | 26.20 ft | on 03-20-1936 | |
| 2. | 23.00 ft | on 09-22-1938 | |
| 3. | 20.80 ft | on 11-05-1927 | |
| 4. | 15.12 ft | on 05-15-2006 | |
| 5. | 14.65 ft | on 04-06-1960 | 1 |
| 6. | 14.40 ft | on 04-04-1951 | |
| 7. | 14.28 ft | on 04-19-1969 | |
| 8. | 13.69 ft | on 03-28-1953 | |
| 9. | 13.63 ft | on 03-31-1998 | |
| 10. | 13.41 ft | on 03-03-1987 | |
| 11. | 13.28 ft | on 09-18-1999 | |
| 12. | 13.03 ft | on 12-23-1973 | |
| 13. | 12.92 ft | on 05-31-1984 | |
| 14. | 12.80 ft | on 04-20-1997 | |
| 15. | 12.67 ft | on 04-25-2001 | |
| 16. | 12.55 ft | on 04-15-1994 | |
| 17. | 12.53 ft | on 04-15-2004 | |
| 18. | 12.41 ft | on 04-12-1993 | |
| 19. | 12.41 ft | on 05-01-1988 | |
| 20. | 12.37 ft | on 04-16-2002 | |
| 21. | 12.34 ft | on 04-11-2000 | |
| 22. | 12.03 ft | on 05-08-1989 | |
| 23. | 11.95 ft | on 10-08-1991 | |
| 24. | 11.86 ft | on 05-21-1983 | |
| 25. | 11.86 ft | on 04-06-2005 | |
| 26. | 11.84 ft | on 04-01-1986 | |
| 27. | 11.51 ft | on 04-24-1991 | |
| 28. | 11.31 ft | on 03-31-2003 |
Vertical Datum Table
| type | NAVD88 |
|---|---|
| major Flooding | 236.56 ft |
| moderate Flooding | 233.56 ft |
| minor Flooding | 230.56 ft |
| action | 228.56 ft |
| Latest Value | 220.10 ft |
| Gauge Zero | 216.56 ft |
Gauge Photos
No Images Found
Probability Information
No Images Available
Unique Local Info
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Potential River Levels Used to Estimate the Chance of Flooding and the Range of Possible River Levels |
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| 10 day (HEFS) | 7 Day (NAEFS) | 7 Day (GEFS) |
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Note: Use the official hydrograph at the top of this web page for river levels within the next 48 hours.
See the Product Description Document link for more details on the interpretation of the 3,7 day graphics.
Click individual graphics to enlarge.
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.