The monitoring network within this area

Hydrionis holds 383 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

383

Values held

1914–2026

Record spans

Gauges within the Middle 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 RIVER AT AFTON, WI

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1914–2025.

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	ROCK RIVER AT AFTON, WI (m³/s)
1914	200
1915	297
1916	262
1917	256
1918	360
1919	101
1920	286
1921	232
1922	245
1923	294
1924	201
1925	134
1926	147
1927	163
1928	189
1929	368
1930	131
1931	39.1
1932	124
1933	255
1934	81.8
1935	180
1936	130
1937	241
1938	260
1939	164
1940	303
1941	141
1942	93.4
1943	314
1944	216
1945	108
1946	283
1947	127
1948	266
1949	156
1950	180
1951	222
1952	278
1953	176
1954	131
1956	126
1957	98.0
1958	63.1
1959	343
1960	250
1961	171
1962	257
1963	115
1964	71.6
1965	170
1966	147
1967	143
1968	143
1969	134
1970	85.2
1971	167
1972	146
1973	274
1974	232
1975	294
1976	191
1977	73.6
1978	182
1979	326
1980	165
1982	228
1983	176
1984	151
1985	219
1986	263
1988	119
1989	115
1990	169
1991	152
1993	303
1994	165
1995	107
1996	241
1997	179
1998	204
1999	202
2000	270
2001	154
2002	126
2003	104
2004	281
2005	143
2006	131
2007	237
2008	473
2009	292
2010	271
2011	226
2012	133
2013	340
2014	198
2015	134
2016	176
2017	212
2018	303
2019	297
2021	138
2022	136
2023	195
2024	281
2025	151

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	1914–2025
Completeness	95.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	5 separate periods inside 1914–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1914 and is not continuous from it: 112 years separate the first value from the last, and 96% 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 ROCK RIVER AT AFTON, WI, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1914–2025.

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	ROCK RIVER AT AFTON, WI (mm)
1914	163
1915	272
1916	286
1917	260
1918	229
1919	135
1920	206
1921	199
1922	245
1923	184
1924	216
1925	110
1926	159
1927	232
1928	237
1929	284
1930	137
1931	90.0
1932	106
1933	181
1934	67.0
1935	147
1936	97.0
1937	160
1938	287
1939	148
1940	117
1941	166
1942	147
1943	214
1944	150
1945	137
1946	176
1947	156
1948	163
1949	109
1950	203
1951	269
1952	280
1953	171
1954	157
1955	158
1956	128
1957	114
1958	67.0
1959	198
1960	335
1961	199
1962	177
1963	80.0
1964	59.0
1965	212
1966	178
1967	148
1968	127
1969	181
1970	110
1971	166
1972	234
1973	355
1974	312
1975	269
1976	179
1977	111
1978	238
1979	283
1980	226
1981	207
1982	272
1983	237
1984	282
1985	320
1986	399
1987	202
1988	156
1989	135
1990	184
1991	215
1992	206
1993	407
1994	190
1995	207
1996	257
1997	229
1998	250
1999	251
2000	248
2001	284
2002	201
2003	132
2004	315
2005	164
2006	251
2007	301
2008	511
2009	372
2010	388
2011	309
2012	170
2013	388
2014	292
2015	221
2016	342
2018	514
2019	528
2020	379
2021	195
2022	256
2023	259
2024	377
2025	228

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	1914–2025
Completeness	99.1% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1914–2025 holds no value: 2017. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1914 and is not continuous from it: 112 years separate the first value from the last, and 99% of the years between them are held. The span is not the record.
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 Middle Rock and what each holds
Gauge	Measures	Values	Record
ROCK RIVER AT AFTON, WI	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	369	1914–2026
WHITEWATER CR AT WILLIS RAY RD NEAR WHITEWATER, WI	catchment area, annual maximum river flow	14	1927–2026

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 — 07090002. 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 RIVER AT AFTON, WI	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
WHITEWATER CR AT WILLIS RAY RD NEAR WHITEWATER, WI	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 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	1	no
Years spanned	113	yes, 20 or more
Values held	383	no
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-05430500.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), Middle Rock gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-middle-rock/

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 Middle 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 confidence2025-08-19

Source: USGS — National Water Information System, USGS site 05430500, 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.