River Report

Souhegan River river

2 streamgauges 63% of normal Last updated 2026-05-25
Aggregate flow
315cfs
% of normal
63%
Daily volume
625AF
Seasonal avg
502cfs

Total streamflow across the Souhegan River was last observed at 315 cfs, and is expected to yield approximately 625 acre-ft of water today; about 63% of normal. River levels are low and may signify a drought. Average streamflow for this time of year is 502 cfs, with recent peaks last observed on 2023-12-19 when daily discharge volume was observed at 6,040 cfs.

Maximum discharge along the river is currently at the Souhegan River At Merrimack reporting a streamflow rate of 334 cfs. However, the streamgauge with the highest stage along the river is the Souhegan River (Site Wlr-1) Near Milford with a gauge stage of 4.39 ft. This river is monitored from 2 different streamgauging stations along the Souhegan River, the highest being situated at an altitude of 275 ft, the Souhegan River (Site Wlr-1) Near Milford.

Max discharge

Souhegan River At Merrimack

334cfs
Highest-elevation gauge

Souhegan River (Site Wlr-1) Near Milford

275ft
Aggregate trend

River streamflow levels

Daily aggregate streamflow across every monitored gauge along the Souhegan River. Use the range buttons to zoom in on a specific period.

Total streamflow

Sum of all monitored streamgauges · daily

Per-gauge breakdown

Every streamgauge along the Souhegan River

All 2 USGS gauges Snoflo tracks for this river, with current flow, stage, recent change, percent of normal, and the gauge's all-time min / max. Click any header to sort. Cells are heatmapped relative to the column min/max -- darker blue = higher.

Streamgauge Streamflow (cfs) Gauge stage (ft) 24h Δ (%) % Normal Min (cfs) Max (cfs) Elevation (ft)
Souhegan River (Site Wlr-1) Near Milford NH
USGS 01093852
226 4.39 72.2 109% 2 4,310 275
Souhegan River At Merrimack NH
USGS 01094000
334 3.44 17.0 66% 6 3,800 172
Annual peaks

Maximum streamflow discharge by year

The single highest aggregate discharge recorded each year. Spotting the multi-year trend reveals droughts vs. wet cycles long before the headline daily flow does.

Annual peak discharge

From the river's full record · one point per water year

Profile

Streamflow elevation profile

Each bubble is one gauge along the river, plotted by current streamflow (x-axis) vs elevation (y-axis), sized by gauge stage. Reading top-to-bottom traces the river from headwaters down to its mouth -- you can see flow accumulate as elevation drops.

Elevation vs streamflow

One point per monitored gauge · bubble size = gauge stage

About this river

Souhegan River

The Souhegan River is a 33-mile-long river in southern New Hampshire that flows from its headwaters in the town of New Ipswich to its confluence with the Merrimack River in the town of Merrimack. The river has a rich history, once powering a variety of mills and factories. Today, the river is used primarily for recreation, including fishing, kayaking, and swimming. The river is also an important source of water for agricultural activities, particularly in the communities of Milford and Wilton. The river is dammed in several locations, including the Pennichuck Brook Dam in Nashua, the Wilton Dam in Wilton, and the Merrimack Village Dam in Merrimack, which impound the water to create reservoirs for drinking water and hydroelectric power generation. Despite its industrial past, the Souhegan River remains an important natural resource for the region.

Around the river

Recreation along the Souhegan River

Fishing access and paddle runs Snoflo tracks within the watershed.

Track the Souhegan River in the Snoflo app

Set per-gauge push alerts (e.g. "alert me when flow at the Russian R Nr Healdsburg crosses 5,000 cfs"), and Snoflo's iOS app pushes the moment USGS reports the crossing.

FAQ

About the Souhegan River

Where does the data for the Souhegan River come from?

Streamflow and gauge stage data are sourced from the U.S. Geological Survey (USGS) National Water Information System. The aggregate flow shown at the top of the page is computed by Snoflo as the sum of all monitored gauges along the river.

How is "percent of normal" calculated?

Today's aggregate streamflow is compared to the historical average aggregate streamflow on this calendar day across the river's full record. 100% means right on average; values above 100% indicate above-normal flow (wet year); values below indicate below-normal (dry year or drought).

Why are some gauges showing very different flows?

Gauges along a river measure flow at different points: headwater gauges read what's coming off the snowpack or mountain runoff; downstream gauges integrate everything upstream, including tributary inputs. Wide spreads usually mean a tributary is contributing significantly between gauges.

What's the elevation profile chart showing?

Each bubble is one gauge along the river, plotted by streamflow (x-axis) and elevation (y-axis), sized by gauge stage. Reading top-down traces the river from headwaters to mouth -- you can see flow build as elevation drops.

Can I get alerts when a specific gauge crosses a threshold?

Yes -- alerts are managed in the Snoflo iOS app on a per-gauge basis. Open any individual streamgauge from the table above and favorite it to set a discharge threshold.