The monitoring network within this area

Hydrionis holds 550 values from 2 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

550

Values held

1904–2026

Record spans

Gauges within the Upper Allegheny huc8 subbasin

2 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 ALLEGHENY RIVER AT SALAMANCA NY

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1904–2025.

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	ALLEGHENY RIVER AT SALAMANCA NY (m³/s)
1904	804
1905	866
1906	419
1908	821
1909	1,070
1910	1,161
1911	558
1912	773
1913	1,070
1914	900
1915	603
1916	1,036
1917	532
1918	850
1919	606
1920	892
1921	382
1922	459
1923	648
1924	578
1925	680
1926	487
1927	524
1929	750
1930	552
1931	425
1932	493
1933	439
1934	532
1935	547
1936	869
1937	691
1938	578
1939	714
1940	861
1941	572
1942	1,283
1944	530
1945	674
1946	988
1947	1,048
1948	1,090
1949	292
1950	852
1952	660
1953	544
1954	470
1955	714
1956	1,390
1957	725
1958	634
1959	991
1960	816
1961	917
1962	362
1963	765
1964	971
1965	507
1966	470
1967	1,181
1969	538
1970	566
1971	527
1972	2,067
1974	507
1975	736
1976	903
1977	592
1978	629
1979	631
1980	459
1981	759
1982	496
1984	838
1985	631
1986	456
1987	447
1988	388
1989	1,014
1990	561
1992	439
1993	841
1994	600
1996	1,121
1997	564
1998	892
1999	620
2000	462
2001	416
2002	515
2003	668
2004	697
2005	648
2007	852
2008	725
2009	631
2010	694
2012	337
2013	450
2015	479
2016	399
2017	847
2018	807
2019	439
2020	419
2021	476
2022	742
2024	572
2025	413

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	1904–2025
Completeness	89.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	13 separate periods inside 1904–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1904 and is not continuous from it: 122 years separate the first value from the last, and 89% of the years between them are held. The span is not the record.
Last read from the publisher	2026-08-31
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 ALLEGHENY RIVER AT SALAMANCA NY, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1904–2025.

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	ALLEGHENY RIVER AT SALAMANCA NY (mm)
1904	734
1905	561
1906	536
1907	584
1908	658
1909	637
1910	713
1911	746
1912	595
1913	665
1914	524
1915	640
1916	815
1917	720
1918	601
1919	565
1920	439
1921	529
1922	445
1923	456
1924	577
1925	521
1926	589
1927	826
1928	556
1929	774
1930	444
1931	464
1932	544
1933	508
1934	365
1935	499
1936	588
1937	746
1938	526
1939	509
1940	662
1941	347
1942	767
1943	721
1944	494
1945	889
1946	538
1947	746
1948	621
1949	449
1950	786
1951	629
1952	662
1953	525
1954	502
1955	571
1956	811
1957	480
1958	543
1959	721
1960	489
1961	587
1962	431
1963	427
1964	495
1965	508
1966	471
1967	735
1968	505
1969	526
1970	695
1971	480
1972	931
1973	569
1974	680
1975	689
1976	629
1977	844
1978	544
1979	692
1980	472
1981	618
1982	599
1983	491
1984	762
1985	520
1986	598
1987	577
1988	399
1989	616
1990	802
1991	404
1992	690
1993	615
1994	764
1995	419
1996	843
1997	600
1998	486
1999	435
2000	505
2001	394
2002	601
2003	829
2004	776
2005	573
2006	719
2007	606
2008	581
2009	546
2010	516
2011	847
2012	472
2013	565
2014	598
2015	589
2016	516
2017	706
2018	861
2019	687
2020	535
2021	604
2022	546
2023	461
2024	558
2025	512

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	1904–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1904 to 2025 is held.
Last read from the publisher	2026-08-24
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 Upper Allegheny and what each holds
Gauge	Measures	Values	Record
ALLEGHENY RIVER AT SALAMANCA NY	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	281	1904–2026
Brokenstraw Creek at Youngsville, PA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	269	1910–2026

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 — 05010001. 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
ALLEGHENY RIVER AT SALAMANCA NY	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	2026-08-26
Brokenstraw Creek at Youngsville, PA	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	2026-08-26

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 3 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	123	yes, 20 or more
Values held	550	no
Distinct measurements	4	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-03011020.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), Upper Allegheny gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-upper-allegheny/

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 Upper Allegheny 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 confidence2025-03-06

Source: USGS — National Water Information System, USGS site 03011020, 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 31 August 2026.