Merrimack River below Concord River at Lowell, MA

USGS Site No: 01100000Merrimack River • Middlesex County, MA

Merrimack River below Concord River at Lowell, MA on the Merrimack River is currently at 7,160 cfs (Normal — 66th percentile for this date) . Gage height: 44.00 ft.

Reading from

7,160
CFS Discharge
44.00
Gage Height (ft)
Normal
Flow Condition
Normal
Flood Status

Historical Percentile Comparison

Today's discharge compared to the long-term record for June 11 at this station. Percentile rank shows what fraction of historical years had lower flow on this date.

Percentile Label CFS Threshold Today's Flow
10th Very Low threshold 2,450
25th Low threshold 3,550
50th (Median) Normal (median) 4,950
75th High threshold 8,400 Today: 7,160 cfs
95th Very High threshold 20,400

30-Day Hydrograph

Recent discharge plotted against the historical 10th–95th percentile envelope for the same calendar days. Source: USGS daily values + long-term statistics.

50k 25k 0 cfs Apr 6 May 28
10th–95th historical Day-of-year median Recent discharge

30-Day Flow History

Date Discharge (CFS) Gage Ht (ft)
May 28, 2026 8,890
May 27, 2026 10,200
May 26, 2026 9,290
May 25, 2026 7,120
May 24, 2026 6,420
May 23, 2026 6,900
May 22, 2026 7,860
May 21, 2026 9,340
May 20, 2026 11,600
May 19, 2026 15,200
May 18, 2026 21,000
May 17, 2026 25,500
May 16, 2026 22,600
May 15, 2026 11,100
Apr 21, 2026 11,900
Apr 20, 2026 11,400
Apr 19, 2026 13,200
Apr 18, 2026 13,700
Apr 17, 2026 12,700
Apr 16, 2026 12,100
Apr 15, 2026 9,610
Apr 14, 2026 8,330
Apr 13, 2026 8,640
Apr 12, 2026 8,830
Apr 11, 2026 9,530
Apr 10, 2026 10,700
Apr 9, 2026 11,800
Apr 8, 2026 13,300
Apr 7, 2026 15,300
Apr 6, 2026 16,000

Station Information

USGS Site No
01100000
State
MA
Coordinates
42.6459, -71.2984
Drainage Area
4,635 mi²
Datum (ft)
4.4
HUC Code
01070006
View on USGS NWIS →

Flood Stage Thresholds

Action Stage
50.0 ft
Flood Stage
52.0 ft
Moderate Flood
54.0 ft
Major Flood
58.0 ft

Currently 8.00 ft below flood stage.

Recent Extremes

Max discharge
44,200 cfs
May 11, 2025
Min discharge
681 cfs
Sep 23, 2025
Days at flood stage
0

Computed from the local daily-values archive.

Nearby Gauges