The monitoring network within this area

Hydrionis holds 2,410 values from 9 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

2,410

Values held

1895–2026

Record spans

Gauges within the Upper Tuolumne huc8 subbasin

9 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 ELEANOR C NR HETCH HETCHY CA

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	ELEANOR C NR HETCH HETCHY CA (m³/s)
1915	43.6
1916	45.6
1917	44.7
1918	27.0
1919	45.6
1920	41.6
1921	45.6
1922	53.2
1923	68.0
1924	52.7
1925	122
1926	33.4
1927	52.1
1928	181
1929	101
1930	25.1
1931	21.2
1932	35.4
1933	28.6
1934	18.0
1935	43.9
1936	71.6
1937	50.7
1939	21.0
1940	93.4
1941	49.3
1942	63.1
1943	98.5
1944	34.3
1945	151
1947	21.9
1948	36.0
1949	40.8
1950	30.9
1952	49.6
1953	81.0
1954	73.9
1955	26.2
1957	24.5
1958	52.1
1959	19.0
1960	14.2
1961	4.22
1962	21.4
1963	294
1964	0.566
1966	1.87
1967	45.9
1968	16.8
1969	53.8
1970	96.0
1971	8.27
1973	42.2
1974	34.8
1975	36.5
1976	0.566
1977	0.396
1978	40.2
1979	31.1
1980	192
1981	36.5
1982	246
1983	145
1984	0.708
1986	168
1987	15.2
1988	14.8
1989	6.46
1991	1.70
1992	0.708
1993	27.1
1994	10.5
1995	117
1996	197
1997	552
1998	58.3
1999	38.8
2000	98.0
2001	14.6
2002	19.1
2004	25.8
2005	210
2007	9.97
2008	22.0
2009	75.9
2010	40.2
2012	48.7
2014	27.8
2015	2.35
2016	17.0
2017	292
2019	65.7
2020	28.6
2021	15.0
2022	209
2024	48.7
2025	29.4

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	1915–2025
Completeness	87.4% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	14 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 87% 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 TUOLUMNE R A MODESTO CA, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1941–2024.

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	TUOLUMNE R A MODESTO CA (mm)
1941	453
1942	457
1943	420
1944	151
1945	319
1946	276
1947	108
1948	148
1949	121
1950	341
1951	264
1952	545
1953	161
1954	156
1955	155
1956	469
1957	146
1958	489
1959	100
1960	71.0
1961	40.0
1962	131
1963	290
1964	120
1965	366
1966	147
1967	446
1968	114
1969	642
1970	216
1971	122
1972	79.0
1973	107
1974	200
1975	236
1976	87.0
1977	28.0
1978	163
1979	248
1980	479
1981	122
1982	656
1983	1,009
1984	318
1985	109
1986	382
1987	76.0
1988	33.0
1989	39.0
1990	36.0
1991	38.0
1992	39.0
1993	106
1994	53.0
1995	635
1996	409
1997	506
1998	582
1999	264
2000	241
2001	100
2002	66.0
2003	73.0
2004	88.0
2005	417
2006	572
2007	67.0
2008	63.0
2009	60.0
2010	235
2011	572
2012	66.0
2013	46.0
2014	36.0
2015	31.0
2016	53.0
2017	915
2018	140
2019	426
2020	55.0
2021	34.0
2022	37.0
2023	692
2024	239

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	1941–2024
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1941 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 Upper Tuolumne and what each holds
Gauge	Measures	Values	Record
M TUOLUMNE R A OAKLAND RECREATION CAMP CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	291	1916–2026
TUOLUMNE R A MODESTO CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	291	1895–2026
TURLOCK CN NR LA GRANGE CA	burned area within 50 km, mean river flow, mean river flow, water year	287	1899–2024
ELEANOR C NR HETCH HETCHY CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	277	1915–2026
SF TUOLUMNE R NR OAKLAND RECREATION CAMP CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	271	1923–2026
MODESTO CN NR LA GRANGE CA	burned area within 50 km, mean river flow, mean river flow, water year	267	1909–2025
TUOLUMNE R NR HETCH HETCHY CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	262	1915–2026
FALLS C NR HETCH HETCHY CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	237	1915–2026
TUOLUMNE R AB LA GRANGE DAM NR LA GRANGE CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	227	1897–2026

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 — 18040009. 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
M TUOLUMNE R A OAKLAND RECREATION CAMP CA	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
TUOLUMNE R A MODESTO CA	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
TURLOCK CN NR LA GRANGE CA	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
ELEANOR C NR HETCH HETCHY CA	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
SF TUOLUMNE R NR OAKLAND RECREATION CAMP CA	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
MODESTO CN NR LA GRANGE CA	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
TUOLUMNE R NR HETCH HETCHY CA	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
FALLS C NR HETCH HETCHY CA	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
TUOLUMNE R AB LA GRANGE DAM NR LA GRANGE CA	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	9	yes, 3 or more
Years spanned	132	yes, 20 or more
Values held	2,410	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-11282000.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 Tuolumne gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-tuolumne/

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 Tuolumne 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 confidence2001-12-02

Source: USGS — National Water Information System, USGS site 11282000, 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.