Merrimack River
River in Massachusetts, read from its USGS gauge, draining about 4,635 square miles. Figures refresh every fifteen minutes.
Discharge
1,530
cfs · 56 min ago
Normal for today
2,610
cfs median, 103 yrs
Water temp
—
not measured here
Gage height
41.78
ft
Reading the number
On this date the gauge has averaged 2,610 cfs over 103 years of record, with the middle half of years falling between 1,590 and 4,260 cfs. Today is below that band: lower, clearer and, in summer, warmer water than a typical October day here.
Regional hatch calendar
What is likely hatching near Merrimack River
Merrimack River does not have its own verified chart yet. This calendar is combined from the verified charts on Millers River (58 mi), Saco River (94 mi), West Branch Farmington River (100 mi). Treat it as regional timing, and file a report if you see something different here.
| Insect | J | F | M | A | M | J | J | A | S | O | N | D |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Blue-Winged Olive | January: absent | February: absent | March: active | April: peak | May: active | June: active | July: active | August: active | September: peak | October: peak | November: active | December: absent |
| Caddis | January: absent | February: absent | March: absent | April: active | May: peak | June: peak | July: active | August: active | September: peak | October: active | November: absent | December: absent |
| Hendrickson | January: absent | February: absent | March: absent | April: peak | May: peak | June: active | July: absent | August: absent | September: absent | October: absent | November: absent | December: absent |
| Light Cahill | January: absent | February: absent | March: absent | April: absent | May: absent | June: peak | July: active | August: active | September: active | October: absent | November: absent | December: absent |
| Terrestrials | January: absent | February: absent | March: absent | April: absent | May: absent | June: active | July: peak | August: peak | September: peak | October: active | November: absent | December: absent |
| Golden Stonefly | January: absent | February: absent | March: absent | April: absent | May: active | June: peak | July: active | August: absent | September: absent | October: absent | November: absent | December: absent |
| Sulphur | January: absent | February: absent | March: absent | April: absent | May: peak | June: peak | July: active | August: absent | September: absent | October: absent | November: absent | December: absent |
| Trico | January: absent | February: absent | March: absent | April: absent | May: absent | June: active | July: peak | August: peak | September: active | October: absent | November: absent | December: absent |
| Brown Drake | January: absent | February: absent | March: absent | April: absent | May: active | June: peak | July: active | August: absent | September: absent | October: absent | November: absent | December: absent |
| Gray Drake | January: absent | February: absent | March: absent | April: absent | May: active | June: peak | July: active | August: absent | September: absent | October: absent | November: absent | December: absent |
| Green Drake | January: absent | February: absent | March: absent | April: absent | May: absent | June: peak | July: absent | August: absent | September: absent | October: absent | November: absent | December: absent |
| Isonychia | January: absent | February: absent | March: absent | April: absent | May: absent | June: active | July: active | August: active | September: peak | October: active | November: absent | December: absent |
Reports
From anglers on Merrimack River
No reports filed here yet. The first one becomes the page’s local knowledge, stamped with the flow at the time. File a report.