Delaware And Raritan Canal At Port Mercer Flow Report

New Jersey, USA USGS #01460440 ↗

As of August 2, 2026, Delaware And Raritan Canal At Port Mercer is flowing at 129 cfs with a gage height of 55.19 ft. Source: USGS gauge #01460440, refreshed throughout the day.

⚠ Flood Watch · Flood Watch issued August 2 at 2:20PM EDT until August 3 at 11:00PM EDT by NWS Mount Holly NJ
Stale data This gauge hasn’t reported in days (last reading unknown). The readings below may not reflect current conditions.
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Delaware And Raritan Canal At Port Mercer
USGS gauge #01460440
129 cfs streamflow
Latest reading from this gauge.
Gage height
55.19ft
Water temp
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% of median
Since yesterday
— 0%
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Conditions summary

Delaware And Raritan Canal At Port Mercer at a glance

How Delaware And Raritan Canal At Port Mercer is running right now, where it sits on the map, and the key gauge stats.

Delaware And Raritan Canal At Port Mercer is flowing at 129 cfs, with the water sitting 55.19 ft at the gage.

This is USGS gauge #01460440 in New Jersey. Over the past 10 days the average has been 125 cfs, peaking at 131 cfs.

For real-time updates and historical context, see the realtime view or the historical comparison. Browse other gauges in the New Jersey flow report.

Delaware And Raritan Canal At Port Mercer on the map Open map →
Site IDUSGS 01460440
Last updated2026-08-02
Gage height, feet55.19 ft
Stream water level elevation above NAVD 1988, in ft52.88 ft
Temperature, water, °C26.0 deg C
Streamflow, ft³/s129.0 ft3/s
Max recorded1,030 cfs
Engineering & permitting

Engineering Data

Flow-duration statistics and observed peak-flow context computed from this gauge’s complete daily record (USGS #01460440).

P10 exceedanceexceeded 10% of days
P25 exceedanceexceeded 25% of days
P50 (median)exceeded half of days
P75 exceedanceexceeded 75% of days
P90 exceedanceexceeded 90% of days
Period of recorddaily observations

Estimate flows at an ungauged site

Drainage-area ratio transfer from this gauge . Most reliable for hydrologically similar sites in the same watershed with area ratios between roughly 0.5 and 1.5.

Conditions report:

Percentiles are flow-duration values computed from this gauge’s observed daily record as archived by Snoflo. Return periods are Weibull plotting-position estimates from observed annual maxima, provided as general reference context only. Always verify against official USGS NWIS records. Part of Snoflo for Engineering.

Streamflow outlook

Streamflow Forecast

Over the next 5 days, Delaware And Raritan Canal At Port Mercer Nj is expected to hold near today's 129 cfs, toward roughly 128 cfs by 2026-08-07 (likely range 109-151 cfs) -- running well below the seasonal normal.

Powered by PULSE — Snoflo’s forecast engine, trained on this gauge’s full record of storms, snowmelt, and dry spells.

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Daily forecast table
DateExpected (p50)Likely range (p25–p75)vs normalProjected stage
Work-window check: flow below cfs
Historical context

How does this compare to past years?

Year-over-year overlay, annual peak discharge, the full distribution of daily flows on record, and the gauge's rating curve.

Detailed forecast

Weather Forecast

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

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Deep dive

5-day forecast table

Every 3 hours, broken out across temperature, snow, rain, humidity, and wind.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
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Long-term outlook

15-day forecast

Daily temperatures, snow, and rain projected over the next two weeks.

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About this location

Delaware And Raritan Canal At Port Mercer

The canal is fed by several sources, including the Delaware River, Millstone River, and Stony Brook. The canal's flow is affected by seasonal trends, with higher flows usually occurring during the winter and spring months due to increased precipitation and snowmelt. There are several dams along the canal, including the Princeton Dam, which regulates water levels in the canal. Interestingly, during the summer months, the canal is used for recreational purposes, such as kayaking and fishing. Overall, the hydrology of the Delaware and Raritan Canal at Port Mercer, NJ, is an important aspect of the local ecosystem and has both practical and recreational uses.

Regional streamflow

Nearby streamflow levels

Cross-check Delaware And Raritan Canal At Port Mercer's discharge against nearby gauges to spot whether the change here is local or regional.

Regional snowpack

Nearby snowpack data

Snowpack at SNOTEL stations near Delaware And Raritan Canal At Port Mercer. Spring snowmelt is the dominant driver of streamflow in mountain basins -- a deep snowpack upstream means more runoff later in the season.

SNOTEL stationSnowpack
Highstown 2w 0 in
Flemington 5 Nnw 0 in
Freehold-Marlboro 0 in
Clinton Twp 3.9 N 0 in
Califon 0.6 Nw 0 in
Mendham 1.5 W 0 in
Nearby recreation

Plan a trip

Reservoirs, boat launches, river runs, and fishing spots within driving distance of Delaware And Raritan Canal At Port Mercer.

River levels & flood safety

Read the level before you go
A river that's runnable at one flow can be deadly at another. Check current discharge and gage height — like the values shown above — against the flood-stage thresholds, and remember levels can spike fast after rain or a dam release.
Respect cold water
Snowmelt rivers run cold even in summer. Sudden immersion triggers cold-water shock and saps strength within minutes. Wear a PFD, dress for the water temperature (not the air), and never wade or paddle alone.
Watch for swiftwater hazards
Strainers (downed trees), undercut rocks, and low-head dams are the deadliest features on moving water. High, fast, muddy water hides them. If in doubt, scout from shore and portage.
Mind flash floods & releases
Narrow canyons can flood from a storm miles upstream, and dam-controlled reaches can rise without warning. Know the forecast, the release schedule, and your exit before you launch.

Track Delaware And Raritan Canal At Port Mercer in the Snoflo app

Save this gauge as a favorite, set push alerts when streamflow crosses a threshold (e.g. "alert me when Delaware And Raritan Canal At Port Mercer crosses 5,000 cfs"), and Snoflo's iOS app will push the moment USGS reports the crossing.

FAQ

About Delaware And Raritan Canal At Port Mercer

What is the Delaware And Raritan Canal At Port Mercer flow rate right now?

As of August 2, 2026, Delaware And Raritan Canal At Port Mercer is flowing at 129 cfs. The live value, gage height, and 24-hour trend are shown at the top of this page.

Is the Delaware And Raritan Canal At Port Mercer running high or low right now?

Check the percent of median figure on this page: above 100% means Delaware And Raritan Canal At Port Mercer is running higher than normal for the date, below 100% means lower. The 24-hour trend shows whether it's rising or falling.

Where does the streamflow data for Delaware And Raritan Canal At Port Mercer come from?

Discharge, gage height, and water temperature come directly from the USGS streamflow gauge 01460440. Snoflo refreshes the time series throughout the day. Forecasts come from the NOAA / yr.no feed Snoflo's iOS app uses.

How often is the report updated?

USGS gauges report continuously (typically every 15 minutes). Snoflo pulls fresh values throughout the day — look for the "as of" timestamp on the streamflow hero card.

What's the difference between discharge and gage height?

Discharge (cubic feet per second, or cfs) is the volume of water flowing past the gauge each second. Gage height is how high the water sits at the gauge (feet). They're related by a rating curve specific to each gauge — higher water means more flow, but the exact ratio depends on channel shape.

How is "percent of median" calculated?

Today's discharge is compared to the historical median discharge on this calendar day across the gauge's full record. 100% = right on median; 200% = a very high year; 30% = a drought-level low.

What are flood stages, and is this river safe right now?

Flood stages are NWS-defined gage-height thresholds — Action, Minor, Moderate, Major — marking when nearby roads or floodplains start to be affected. "Safe" depends on your activity and skill: a level that's a fun paddle for an expert can be lethal for a wader. Always check the current level against the thresholds above and the safety links, and when in doubt, stay off the water.

Can I get alerts when Delaware And Raritan Canal At Port Mercer rises?

Yes — flow alerts are managed in the Snoflo iOS app. Favorite this gauge, set a streamflow threshold (e.g. "alert me when discharge crosses 5,000 cfs"), and you'll get a push the moment USGS reports the crossing.