The monitoring network within this area

Hydrionis holds 2,389 values from 14 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

2,389

Values held

1917–2026

Record spans

Gauges within the Upper San Joaquin huc8 subbasin

14 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 BEAR C NR LAKE THOMAS A EDISON CA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1922–2025.

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	BEAR C NR LAKE THOMAS A EDISON CA (m³/s)
1922	24.3
1923	18.6
1924	12.3
1925	20.0
1926	21.0
1927	23.2
1928	19.1
1929	13.6
1930	14.7
1931	11.3
1932	23.9
1933	24.2
1934	8.38
1935	20.4
1936	43.3
1937	24.0
1938	34.8
1939	11.3
1940	26.1
1941	26.4
1942	21.5
1943	25.8
1944	17.0
1945	24.1
1946	17.3
1947	19.3
1948	17.0
1949	17.4
1950	18.6
1951	27.5
1952	24.2
1953	15.7
1954	15.7
1955	27.6
1956	47.6
1957	32.8
1958	29.7
1959	10.9
1960	11.6
1961	11.2
1962	22.3
1963	33.7
1964	14.7
1965	23.3
1966	11.5
1967	39.6
1968	11.9
1969	39.4
1970	18.4
1971	20.2
1972	51.0
1973	23.0
1974	24.8
1975	22.0
1976	12.0
1977	10.00
1978	99.7
1979	25.2
1980	30.6
1981	25.6
1982	104
1983	39.9
1984	24.0
1985	11.8
1986	47.6
1987	19.0
1988	13.6
1989	11.3
1990	9.66
1991	23.1
1992	11.0
1993	28.9
1994	14.7
1995	46.7
1996	24.8
1997	49.8
1998	31.7
1999	22.1
2000	26.6
2001	18.0
2002	16.7
2003	38.8
2004	12.8
2005	30.6
2006	35.1
2007	9.37
2008	19.9
2009	18.2
2010	39.1
2011	48.1
2012	12.6
2013	11.0
2014	12.4
2015	6.99
2016	22.1
2017	44.7
2018	62.3
2019	31.7
2020	13.7
2021	8.92
2022	13.5
2023	37.7
2024	18.0
2025	17.4

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	1922–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1922 to 2025 is held.
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 BEAR C NR LAKE THOMAS A EDISON 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. 1922–2024.

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	BEAR C NR LAKE THOMAS A EDISON CA (mm)
1922	755
1923	546
1924	187
1925	618
1926	469
1927	751
1928	430
1929	382
1930	345
1931	223
1932	676
1933	435
1934	282
1935	626
1936	732
1937	716
1938	1,109
1939	365
1940	707
1941	937
1942	728
1943	638
1944	474
1945	777
1946	660
1947	475
1948	431
1949	424
1950	553
1951	632
1952	881
1953	456
1954	484
1955	497
1956	926
1957	553
1958	848
1959	324
1960	326
1961	301
1962	670
1963	735
1964	369
1965	735
1966	447
1967	1,033
1968	310
1969	1,296
1970	565
1971	586
1972	435
1973	714
1974	721
1975	607
1976	264
1977	236
1978	1,187
1979	661
1980	965
1981	496
1982	1,154
1983	1,299
1984	722
1985	473
1986	894
1987	358
1988	381
1989	382
1990	326
1991	448
1992	340
1993	877
1994	411
1995	1,179
1996	735
1997	763
1998	1,023
1999	565
2000	625
2001	422
2002	488
2003	581
2004	516
2005	864
2006	1,101
2007	286
2008	456
2009	527
2010	676
2011	998
2012	339
2013	318
2014	316
2015	238
2016	620
2017	1,283
2018	546
2019	894
2020	327
2021	227
2022	316
2023	1,224
2024	553

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	1922–2024
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1922 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 San Joaquin and what each holds
Gauge	Measures	Values	Record
BEAR C NR LAKE THOMAS A EDISON CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	348	1921–2026
MONO C BL LK THOMAS A EDISON CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	346	1921–2026
PITMAN C BL TAMARACK C CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	328	1928–2026
BIG C BL HUNTINGTON LK CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	285	1925–2026
WARD TUNNEL A INTAKE A FLORENCE LAKE CA	burned area within 50 km, mean river flow, mean river flow, water year	233	1925–2024
PORTAL POWERPLANT AT HUNTINGTON LAKE CA	burned area within 50 km, mean river flow, mean river flow, water year	231	1927–2024
SF SAN JOAQUIN R NR FLORENCE LK CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	207	1921–2026
HUNTINGTON-SHAVER CONDUIT OTLT NR SHAVER LK CA	burned area within 50 km, mean river flow, mean river flow, water year	145	1929–2019
BIG C NR MOUTH NR BIG CREEK CA	catchment area, annual maximum river flow	48	1923–2026
SAN JOAQUIN R A MILLER CROSSING CA	catchment area, annual maximum river flow	47	1922–2026
STEVENSON C A SHAVER LK CA	catchment area, annual maximum river flow	46	1917–2026
GRANITE C NR CATTLE MOUNTAIN CA	catchment area, annual maximum river flow	42	1922–2026
SAN JOAQUIN R AB BIG CREEK CA	catchment area, annual maximum river flow	42	1922–2026
SAN JOAQUIN R BL KERCKHOFF PH NR PRATHER CA	catchment area, annual maximum river flow	41	1937–2026

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 — 18040006. 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
BEAR C NR LAKE THOMAS A EDISON 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
MONO C BL LK THOMAS A EDISON 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
PITMAN C BL TAMARACK C 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
BIG C BL HUNTINGTON LK 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
WARD TUNNEL A INTAKE A FLORENCE LAKE 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
PORTAL POWERPLANT AT HUNTINGTON LAKE 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 SAN JOAQUIN R NR FLORENCE LK 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
HUNTINGTON-SHAVER CONDUIT OTLT NR SHAVER LK 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
BIG C NR MOUTH NR BIG CREEK 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
SAN JOAQUIN R A MILLER CROSSING 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
STEVENSON C A SHAVER LK 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
GRANITE C NR CATTLE MOUNTAIN 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
SAN JOAQUIN R AB BIG CREEK 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
SAN JOAQUIN R BL KERCKHOFF PH NR PRATHER 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	8	yes, 3 or more
Years spanned	110	yes, 20 or more
Values held	2,389	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-11230500.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 San Joaquin gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-san-joaquin/

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 San Joaquin 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 confidence2025-06-01

Source: USGS — National Water Information System, USGS site 11230500, 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.