The monitoring network within this area

Hydrionis holds 578 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

578

Values held

1929–2026

Record spans

Gauges within the Lower Susquehanna-Penns 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 Penns Creek at Penns Creek, PA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1929–2025.

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	Penns Creek at Penns Creek, PA (m³/s)
1929	114
1931	139
1932	120
1933	334
1934	561
1936	445
1937	113
1939	100.0
1940	385
1941	76.2
1942	247
1943	120
1945	117
1946	231
1947	56.1
1948	135
1950	180
1952	214
1953	176
1954	200
1955	103
1956	241
1957	81.0
1959	183
1960	160
1961	164
1962	103
1963	101
1964	203
1965	54.9
1966	116
1967	88.3
1968	51.5
1970	172
1971	90.3
1972	980
1973	177
1975	228
1976	145
1977	214
1979	244
1980	156
1981	215
1982	148
1983	131
1984	377
1985	68.0
1986	201
1988	185
1989	179
1990	151
1992	97.7
1993	221
1995	170
1996	716
1998	192
1999	212
2000	66.8
2001	57.8
2002	105
2003	178
2004	453
2005	158
2006	172
2008	272
2009	52.4
2010	200
2011	264
2012	121
2013	114
2014	247
2015	70.2
2016	92.9
2017	131
2018	219
2020	196
2021	303
2022	124
2023	101
2024	204
2025	100.0

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	1929–2025
Completeness	83.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	16 separate periods inside 1929–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1929 and is not continuous from it: 97 years separate the first value from the last, and 84% 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 Penns Creek at Penns Creek, 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. 1930–2025.

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	Penns Creek at Penns Creek, PA (mm)
1930	302
1931	330
1932	388
1933	541
1934	506
1935	424
1936	558
1937	606
1938	374
1939	374
1940	479
1941	295
1942	569
1943	506
1944	434
1945	671
1946	517
1947	438
1948	535
1949	401
1950	662
1951	566
1952	594
1953	521
1954	429
1955	446
1956	648
1957	431
1958	468
1959	432
1960	503
1961	461
1962	408
1963	355
1964	429
1965	239
1966	326
1967	559
1968	415
1969	283
1970	577
1971	451
1972	897
1973	622
1974	554
1975	663
1976	528
1977	731
1978	708
1979	919
1980	401
1981	427
1982	473
1983	638
1984	729
1985	386
1986	520
1987	409
1988	355
1989	513
1990	682
1991	385
1992	403
1993	718
1994	732
1995	383
1996	947
1997	382
1998	657
1999	400
2000	371
2001	302
2002	481
2003	899
2004	816
2005	490
2006	542
2007	364
2008	548
2009	501
2010	530
2011	1,158
2012	477
2013	418
2014	532
2015	426
2016	315
2017	437
2018	1,119
2019	615
2020	482
2021	518
2022	490
2023	493
2024	699
2025	472

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	1930–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1930 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 Lower Susquehanna-Penns and what each holds
Gauge	Measures	Values	Record
Penns Creek at Penns Creek, PA	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	289	1929–2026
East Mahantango Creek near Dalmatia, PA	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	289	1929–2026

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 — 02050301. 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
Penns Creek at Penns Creek, 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
East Mahantango Creek near Dalmatia, 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 2 of them, which makes it a profile, not indexed.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	98	yes, 20 or more
Values held	578	no
Distinct measurements	4	yes, 2 or more
Publishers measuring it	1	no
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-01555000.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), Lower Susquehanna-Penns gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-lower-susquehanna-penns/

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 Lower Susquehanna-Penns 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 confidence2025-05-06

Source: USGS — National Water Information System, USGS site 01555000, 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.