The monitoring network within this area

Hydrionis holds 1,041 values from 5 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

1,041

Values held

1822–2026

Record spans

Gauges within the Schuylkill huc8 subbasin

5 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 Perkiomen Creek at Graterford, PA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1915–2025.

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	Perkiomen Creek at Graterford, PA (m³/s)
1915	705
1917	250
1918	442
1919	493
1921	190
1922	117
1923	125
1924	204
1925	233
1926	100.0
1928	600
1929	416
1931	142
1932	351
1933	980
1934	541
1935	1,130
1936	464
1937	192
1938	396
1939	419
1940	626
1942	855
1943	481
1945	507
1946	898
1947	148
1948	345
1950	309
1952	456
1953	276
1955	685
1957	297
1958	416
1959	199
1960	719
1961	243
1962	351
1963	297
1964	303
1965	411
1966	311
1967	470
1968	462
1969	413
1970	498
1971	725
1972	1,014
1973	597
1975	544
1976	340
1977	527
1978	597
1979	748
1980	399
1981	182
1982	428
1983	473
1984	776
1985	600
1986	300
1987	238
1989	425
1990	583
1992	133
1993	736
1995	609
1996	920
1998	247
1999	954
2000	490
2002	541
2003	654
2004	750
2005	691
2007	535
2008	504
2010	425
2011	1,121
2013	513
2014	855
2015	253
2016	481
2017	314
2018	481
2019	835
2020	1,291
2021	1,824
2022	411
2023	283
2025	280

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	1915–2025
Completeness	82.0% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	20 separate periods inside 1915–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1915 and is not continuous from it: 111 years separate the first value from the last, and 82% 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 Schuylkill River at Pottstown, PA, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1928–2024.

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	Schuylkill River at Pottstown, PA (mm)
1928	664
1929	533
1930	326
1931	283
1932	468
1933	757
1934	589
1935	516
1936	652
1937	593
1938	596
1939	484
1940	592
1941	329
1942	714
1943	565
1944	465
1945	747
1946	516
1947	638
1948	624
1949	479
1950	666
1951	679
1952	919
1953	720
1954	382
1955	568
1956	579
1957	434
1958	599
1959	452
1960	564
1961	520
1962	488
1963	354
1964	456
1965	255
1966	299
1967	494
1968	444
1969	429
1970	595
1971	672
1972	894
1973	826
1974	574
1975	878
1976	707
1977	668
1978	710
1979	836
1980	381
1981	321
1982	537
1983	808
1984	795
1985	372
1986	565
1987	519
1988	500
1989	681
1990	646
1991	420
1992	471
1993	746
1994	708
1995	428
1996	970
1997	453
1998	625
1999	520
2000	592
2001	384
2002	458
2003	970
2004	855
2005	655
2006	761
2007	545
2008	565
2009	618
2010	576
2011	1,054
2012	524
2013	534
2014	648
2015	513
2016	452
2017	583
2018	1,210
2019	875
2020	664
2021	641
2022	566
2023	555
2024	609

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	1928–2024
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1928 to 2024 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 Schuylkill and what each holds
Gauge	Measures	Values	Record
Schuylkill River at Pottstown, PA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	330	1902–2026
Little Schuylkill River at Tamaqua, PA	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	292	1920–2026
Perkiomen Creek at Graterford, PA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	286	1915–2026
Schuylkill River at Reading, PA	catchment area, annual maximum river flow	94	1822–2026
Schuylkill River at Norristown, PA	catchment area, annual maximum river flow	39	1928–2026

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 — 02040203. 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
Schuylkill River at Pottstown, 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	2026-10-02
Little Schuylkill River at Tamaqua, 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	2026-10-02
Perkiomen Creek at Graterford, 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	2026-10-02
Schuylkill River at Reading, 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	2026-10-02
Schuylkill River at Norristown, 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	2026-10-02

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	4	yes, 3 or more
Years spanned	205	yes, 20 or more
Values held	1,041	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-01472000.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), Schuylkill gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-schuylkill/

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 Schuylkill 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 confidence2023-12-19

Source: USGS — National Water Information System, USGS site 01472000, 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.