The monitoring network within this area

Hydrionis holds 4,701 values from 15 gauges within it. Discharge is a property of a gauge and its reach, not of this drainage area, so this page reports the network and its records rather than a single figure.

Gauges

4,701

Values held

1810–2026

Record spans

Gauges within the Hackensack-Passaic huc8 subbasin

15 monitoring points, positioned as the publisher records them.

Flood peaks, as measured

This gauge's flood record, as measured. Unlike a daily mean it is the discharge at the moment the river was highest, which is the figure flood frequency analysis is built on.

Largest measured flow of each year at Ramapo River near Mahwah NJ

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1903–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Published by the gauge's own operator from its sub-daily record; Hydrionis stores the figure rather than recomputing it. A year the gauge did not cover produces no value rather than a low one, and the gaps are stated below the chart. A peak is a property of this gauge and its reach: a larger flood upstream or downstream of it is not in this series.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	Ramapo River near Mahwah NJ (m³/s)
1903	351
1904	65.1
1906	62.9
1907	79.6
1909	97.7
1910	147
1911	103
1912	97.7
1913	79.6
1923	43.0
1924	118
1925	68.2
1926	42.2
1927	146
1929	44.2
1930	39.4
1931	29.4
1932	40.2
1933	160
1934	54.7
1936	220
1938	190
1940	57.5
1941	44.2
1942	45.0
1943	53.2
1945	123
1946	54.4
1947	58.0
1948	51.8
1950	36.5
1951	197
1952	118
1953	71.4
1955	243
1957	55.2
1959	45.9
1960	97.7
1961	88.3
1962	66.8
1964	39.1
1965	56.1
1966	38.5
1967	33.4
1968	248
1969	85.0
1970	95.7
1971	190
1972	74.5
1973	123
1975	83.3
1976	77.6
1977	116
1979	135
1980	185
1981	92.6
1982	71.4
1983	127
1984	343
1985	51.3
1986	95.4
1987	182
1989	148
1990	72.8
1992	52.4
1993	73.1
1995	50.7
1996	93.4
1998	94.6
1999	311
2000	52.7
2002	31.1
2003	72.5
2005	176
2007	251
2008	83.3
2010	289
2011	518
2012	96.6
2014	82.4
2015	35.1
2016	91.5
2017	38.8
2018	76.2
2019	41.9
2021	166
2023	87.5
2025	53.0

About this series

Everything below is a property of the data rather than a rating of it. There is deliberately no single confidence score: how much a gap matters depends on what you are about to do with the series, and only you know that.

Source	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Measured
Period held	1903–2025
Completeness	71.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	27 separate periods inside 1903–2025 hold no value. The longest runs from 1914 to 1922 — 9 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1903 and is not continuous from it: 123 years separate the first value from the last, and 72% of the years between them are held. The span is not the record.
Last read from the publisher	2026-10-01
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

How much of the rain came back out

A discharge in cubic metres per second cannot be compared with anything: the larger number may only mean the larger catchment. Divided by the area draining to the gauge it becomes a depth of water over that land, which answers a question a reader already has — of the rain that fell here, how much came back out as river?

Water leaving the catchment above Passaic River at Little Falls NJ, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1898–2025.

Show relevant events (1 event)Shading marks when something was recorded, not what caused the line.

Computed by Hydrionis from the published annual mean flow and the catchment area the station's own publisher states. It is not a water balance: the difference between rainfall and runoff is not evaporation alone but also change in groundwater storage, water abstracted and taken elsewhere, and water imported by transfer schemes — which is why a catchment can yield more runoff than the rain that fell on it without anything being measured wrongly. A different area figure rescales every value here by the ratio between them.

What the shaded periods are (1 event)

A shaded period marks when something was recorded, not what caused the shape of the line. Where the two coincide, they coincided.

Documented record — A documented event, compiled from cited sources after it happened. The dates are as good as the record, which for older events can mean the month rather than the day.

Event	Type	Period	Standing	Authority
Hurricane Katrina water and sanitation collapse	Flood	2005-08-29 – 2005-09-30	Documented record	Compiled record

Not shown on this chart

The 1976 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
The 2022 drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Yorkshire drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cantareira water crisis, São Paulo — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
Cape Town Day Zero — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.
European drought — This event’s area does not contain this chart’s subject. Sharing a country is not sharing an event, so it is not drawn.

View the data behind this chart

Underlying data
Period	Passaic River at Little Falls NJ (mm)
1898	756
1899	576
1900	446
1901	657
1902	1,080
1903	952
1904	449
1905	500
1906	511
1907	772
1908	644
1909	469
1910	480
1911	468
1912	540
1913	593
1914	460
1915	577
1916	546
1917	353
1918	355
1919	660
1920	790
1921	456
1922	462
1923	407
1924	553
1925	490
1926	491
1927	805
1928	589
1929	457
1930	283
1931	356
1932	419
1933	634
1934	571
1935	371
1936	643
1937	600
1938	682
1939	496
1940	601
1941	345
1942	620
1943	481
1944	426
1945	771
1946	458
1947	547
1948	514
1949	399
1950	400
1951	696
1952	862
1953	575
1954	328
1955	529
1956	438
1957	310
1958	579
1959	337
1960	530
1961	481
1962	316
1963	212
1964	260
1965	123
1966	216
1967	511
1968	429
1969	372
1970	389
1971	645
1972	868
1973	815
1974	522
1975	769
1976	421
1977	533
1978	574
1979	732
1980	416
1981	218
1982	369
1983	799
1984	744
1985	279
1986	531
1987	505
1988	333
1989	576
1990	575
1991	349
1992	371
1993	454
1994	460
1995	297
1996	818
1997	380
1998	501
1999	373
2000	414
2001	320
2002	202
2003	857
2004	559
2005	653
2006	652
2007	531
2008	587
2009	495
2010	604
2011	1,191
2012	301
2013	461
2014	473
2015	269
2016	280
2017	314
2018	867
2019	733
2020	439
2021	638
2022	458
2023	714
2024	670
2025	344

About this series

Source	United States Geological Survey — National Water Information System · US Government work — public domain
How the values came to exist	Derived Computed by Hydrionis
Period held	1898–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1898 to 2025 is held.
Inputs last read	2026-10-01 · when the records this was computed from were last read from their publishers
Calculation date	2026-08-24 · when the calculation method was last versioned, not a reading of any publisher
Redistribution	Permitted by the upstream licences
Commercial reuse	Permitted by the upstream licences. No Hydrionis access tier can widen this.
Methodology	How this was produced

Every gauge Hydrionis holds within this area

Gauges within the Hackensack-Passaic and what each holds
Gauge	Measures	Values	Record
Passaic River at Little Falls NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	391	1810–2026
Rockaway River below Reservoir at Boonton NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	372	1906–2026
Ramapo River near Mahwah NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	364	1902–2026
Wanaque River at Wanaque NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	358	1912–2026
Passaic River near Millington NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	356	1904–2026
Wanaque River at Awosting NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	356	1919–2026
Ramapo River at Pompton Lakes NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	352	1882–2026
Whippany River at Morristown NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	349	1921–2026
Saddle River at Lodi NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	343	1923–2026
Hackensack River at New Milford NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	343	1921–2026
Passaic River near Chatham NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	325	1903–2026
Pequannock River at Macopin Intake Dam NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	325	1903–2026
Pompton River at Pompton Plains NJ	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	294	1903–2026
Passaic River at Paterson NJ	burned area within 50 km, catchment area, mean river flow, mean river flow, water year	151	1897–2026
Beaver Brook at outlet of Splitrock Reservoir NJ	catchment area, annual maximum river flow	22	1925–2026

How these gauges were attached to this water

Assigned by the publisher to a numbered basin Every gauge here is assigned to this drainage area by its own publisher, which issues the area an official code — 02030103. A drainage area is not a river: it contains the tributaries as well as the main channel, and a gauge in it may be on any of them.

What each gauge’s link to this water rests on
Gauge	Evidence	Established
Passaic River at Little Falls NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Rockaway River below Reservoir at Boonton NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Ramapo River near Mahwah NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Wanaque River at Wanaque NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Passaic River near Millington NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Wanaque River at Awosting NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Ramapo River at Pompton Lakes NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Whippany River at Morristown NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Saddle River at Lodi NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Hackensack River at New Milford NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Passaic River near Chatham NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Pequannock River at Macopin Intake Dam NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Pompton River at Pompton Plains NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Passaic River at Paterson NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02
Beaver Brook at outlet of Splitrock Reservoir NJ	Stated by the publisher — USGS site service, huc_cd field — https://waterservices.usgs.gov/nwis/site/ ; named from the USGS Watershed Boundary Dataset 8-digit HU (Subbasin) layer — https://hydro.nationalmap.gov/arcgis/rest/services/wbd/MapServer/4	2026-10-02

What this record holds

Hydrionis decides which waters get a page, and which of those are offered to search, from what is actually held rather than from how the page reads. Five signals are counted; this record has 5 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	14	yes, 3 or more
Years spanned	217	yes, 20 or more
Values held	4,701	yes, 1000 or more
Distinct measurements	5	yes, 2 or more
Publishers measuring it	2	yes, 2 or more
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-01389500.json
How to cite this, and who you must credit
How these figures were produced
Request this at a different scale, format or geography

No bulk download is offered here, which is a licence position rather than a product one: at least one contributing publisher does not permit redistribution. The values can be read on the page, cited, and pointed to at source.

Attribution and citation

Suggested citation for Hydrionis

Hydrionis (2026), Hackensack-Passaic gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-hackensack-passaic/

Cite Hydrionis where you rely on values Hydrionis computed, on the method that produced them, or on the compilation itself. The underlying measurements remain the publishers’ and their attribution requirements apply to you directly.

Recommended, not required. Hydrionis does not claim rights over unmodified public data it relayed, and doing arithmetic on somebody else’s measurements does not make them Hydrionis’s. Cite the version and the access date: the Hackensack-Passaic gauge records changes as publishers release and as methods are revised, and a citation without both cannot be checked later. Full guidance is on cite and reuse.

None of the contributing licences requires attribution. Crediting the publishers is still good practice and they are listed above.

Where these figures come from

MeasuredHigh confidence2023-05-02

Source: USGS — National Water Information System, USGS site 01389500, annual peak streamflow. Licence: Open.

Method: The instantaneous maximum discharge of each water year as published by USGS, dated to the day it occurred. One value per October-to-September water year; where the publisher lists both a systematic and a historic peak for a year, the larger is the annual maximum. Values the publisher marks as maximum daily averages are not held here, because they are not instantaneous peaks. Values marked as bounded rather than measured are held as censored observations carrying the bound. Cubic feet per second are converted to cubic metres per second and the publisher unit is recorded alongside.

Rating curves are extrapolated at extreme discharges, so the largest values in a peak series carry the largest measurement uncertainty. Data from the U.S. Geological Survey National Water Information System, a work of the United States government and therefore in the public domain.

Retrieved 1 October 2026.