The monitoring network within this area

Hydrionis holds 122 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

122

Values held

1917–2026

Record spans

Gauges within the Rock 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 Rock Creek bl Horse Creek nr int'l boundary

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1917–2023.

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	Rock Creek bl Horse Creek nr int'l boundary (m³/s)
1917	70.8
1919	36.0
1920	12.3
1921	23.5
1922	66.0
1923	48.1
1925	102
1926	17.2
1952	145
1957	5.27
1958	40.5
1959	13.1
1960	58.6
1961	2.32
1962	25.5
1963	23.1
1964	3.85
1965	34.3
1966	26.9
1967	57.2
1968	34.0
1969	125
1970	68.2
1971	28.3
1972	44.2
1973	17.4
1974	34.0
1975	28.9
1976	48.7
1977	3.54
1978	114
1979	44.7
1981	25.8
1982	61.2
1983	6.60
1984	2.63
1986	28.3
1987	31.1
1988	1.53
1990	45.6
1991	35.7
1992	9.91
1993	14.4
1994	22.7
1995	4.28
1996	33.7
1997	47.9
1998	0.878
1999	75.0
2000	20.8
2001	2.83
2002	15.8
2003	21.6
2004	31.7
2005	2.41
2007	55.5
2008	1.76
2010	12.9
2012	22.3
2013	20.9
2014	21.9
2015	11.9
2016	7.67
2017	74.2
2018	14.8
2019	50.7
2020	64.8
2021	0.340
2022	7.05
2023	82.4

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	1917–2023
Completeness	65.4% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	10 separate periods inside 1917–2023 hold no value. The longest runs from 1927 to 1951 — 25 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1917 and is not continuous from it: 107 years separate the first value from the last, and 65% 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

Every gauge Hydrionis holds within this area

Gauges within the Rock and what each holds
Gauge	Measures	Values	Record
Rock Creek bl Horse Creek nr int'l boundary	catchment area, annual maximum river flow	71	1917–2026
McEachern Creek at international boundary	catchment area, annual maximum river flow	51	1924–2026

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 — 10050015. 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
Rock Creek bl Horse Creek nr int'l boundary	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
McEachern Creek at international boundary	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	110	yes, 20 or more
Values held	122	no
Distinct measurements	2	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-06169500.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), Rock gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-rock/

Cite Hydrionis where you rely on the compilation, the normalisation, the eligibility judgements or a chart. Where you use an unmodified published value, the publisher’s attribution is the one that is required; crediting Hydrionis as well is welcome and is not something Hydrionis can require of you.

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 Rock 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 confidence2023-04-12

Source: USGS — National Water Information System, USGS site 06169500, 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.