The monitoring network within this area

Hydrionis holds 2,925 values from 8 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.

8

Gauges

2,925

Values held

1901–2026

Record spans

Gauges within the Upper Mokelumne huc8 subbasin

8 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 MOKELUMNE R BL CAMANCHE DAM CA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1905–2024.

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	MOKELUMNE R BL CAMANCHE DAM CA (m³/s)
1905	157
1906	282
1907	722
1908	87.8
1909	371
1911	535
1912	185
1913	158
1914	377
1915	235
1916	303
1917	263
1918	244
1919	214
1920	193
1921	314
1922	254
1923	181
1924	64.0
1925	524
1926	106
1927	223
1928	725
1929	176
1930	115
1931	18.8
1932	120
1933	30.3
1935	149
1936	170
1937	164
1938	161
1939	28.3
1940	191
1941	146
1942	211
1943	265
1944	56.4
1945	169
1947	24.1
1948	120
1949	41.3
1950	127
1952	135
1953	103
1954	56.6
1955	773
1957	145
1958	233
1959	32.8
1960	43.9
1961	18.2
1962	87.8
1963	168
1964	23.3
1965	106
1967	88.9
1969	140
1970	145
1971	48.7
1973	66.5
1975	54.7
1977	15.9
1978	45.9
1979	54.4
1980	129
1982	116
1983	131
1984	27.5
1986	172
1988	10.5
1989	13.0
1990	13.8
1992	15.0
1993	41.6
1995	113
1996	90.3
1997	154
1998	110
1999	89.2
2000	68.5
2001	13.6
2002	16.1
2003	58.6
2004	43.9
2005	72.2
2006	148
2008	16.0
2009	12.9
2011	142
2012	22.9
2014	15.5
2015	34.8
2016	22.0
2017	142
2018	70.8
2019	94.3
2020	22.5
2021	23.4
2023	141
2024	57.2

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	1905–2024
Completeness	84.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	19 separate periods inside 1905–2024 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1905 and is not continuous from it: 120 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 MOKELUMNE R BL CAMANCHE DAM 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. 1905–2024.

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	MOKELUMNE R BL CAMANCHE DAM CA (mm)
1905	419
1906	1,086
1907	1,303
1908	340
1909	979
1910	605
1911	1,147
1912	315
1913	312
1914	824
1915	636
1916	805
1917	636
1918	419
1919	439
1920	389
1921	631
1922	746
1923	498
1924	159
1925	616
1926	315
1927	665
1928	459
1929	231
1930	256
1931	105
1932	442
1933	301
1934	249
1935	435
1936	661
1937	528
1938	934
1939	264
1940	596
1941	597
1942	737
1943	748
1944	284
1945	571
1946	431
1947	201
1948	383
1949	315
1950	783
1951	570
1952	886
1953	408
1954	364
1955	326
1956	789
1957	350
1958	710
1959	153
1960	156
1961	111
1962	326
1963	535
1964	164
1965	721
1966	231
1967	567
1968	195
1969	847
1970	535
1971	387
1972	184
1973	508
1974	543
1975	429
1976	117
1977	94.0
1978	335
1979	387
1980	695
1981	195
1982	1,142
1983	1,392
1984	518
1985	154
1986	785
1987	131
1988	94.0
1989	105
1990	109
1991	98.0
1992	121
1993	398
1994	132
1995	908
1996	649
1997	686
1998	844
1999	503
2000	364
2001	166
2002	178
2003	263
2004	220
2005	581
2006	931
2007	176
2008	151
2009	197
2010	427
2011	814
2012	171
2013	166
2014	146
2015	137
2016	210
2017	1,309
2018	297
2019	777
2020	173
2021	142
2022	158
2023	985
2024	347

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	Derived Computed by Hydrionis
Period held	1905–2024
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1905 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

The snow standing above this water

1 automated snow station sits inside this drainage area, weighing the snowpack rather than measuring how deep it is.

1,845

Fullest snowpack recorded at Blue Lakes, in 2023 (mm of water)

192

Thinnest, in 2015 (mm of water)

April

Month the pack is usually at its fullest

June

Month the pack has gone by, in half of years

Peak snowpack at Blue Lakes

Water years 1981–2026. Each point is the fullest month of that snow season.

A water year runs October to September and is named for the year it ends, so the snow of one winter stays in one point. The value is the fullest month, not the fullest day: a pack that peaked sharply mid-month reads lower here than a single measurement taken at the right moment would.

View the data behind this chart

Underlying data
Period	Blue Lakes (mm)
1981	561
1982	1,308
1983	1,592
1984	776
1985	769
1986	1,071
1987	353
1988	388
1989	732
1990	425
1991	537
1992	498
1993	1,121
1994	441
1995	1,585
1996	890
1997	936
1998	1,078
1999	981
2000	653
2001	520
2002	687
2003	720
2004	707
2005	1,179
2006	1,060
2007	376
2008	664
2009	625
2010	759
2011	1,158
2012	342
2013	502
2014	370
2015	192
2016	738
2017	1,531
2018	451
2019	1,307
2020	632
2021	500
2022	441
2023	1,845
2024	796
2025	573
2026	346

Read against the river

Blue Lakes and NF MOKELUMNE R BL SALT SPRINGS DAM CA both sit in this drainage area, and their records overlap by 44 years. That is the span the two have in common, not a count of years both actually hold — either record may have gaps inside it. The two are shown separately rather than on one axis: millimetres of stored water and cubic metres per second are not commensurable, and a difference between them would mean nothing.

Being in the same drainage area does not put the snowpack upstream of the gauge. A subbasin is an area, and snow on one tributary can join the river below a gauge on another — so a weak relationship here may say more about which tributary was measured than about the snow.

Every gauge Hydrionis holds within this area

Gauges within the Upper Mokelumne and what each holds
Gauge	Measures	Values	Record
MOKELUMNE R BL CAMANCHE DAM CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	399	1904–2026
MF MOKELUMNE R A WEST POINT CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	378	1911–2026
MOKELUMNE R NR MOKELUMNE HILL CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	332	1901–2026
NF MOKELUMNE R BL SALT SPRINGS DAM CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	331	1926–2026
MOKELUMNE R A WOODBRIDGE CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	327	1925–2026
COLE C NR SALT SPRINGS DAM CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	326	1927–2026
WOODBRIDGE CN A WOODBRIDGE CA	burned area within 50 km, mean river flow, mean river flow, water year	230	1926–2023
DRY C NR GALT CA	catchment area, annual maximum river flow	51	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 — 18040012. 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
MOKELUMNE R BL CAMANCHE DAM 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
MF MOKELUMNE R A WEST POINT 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
MOKELUMNE R NR MOKELUMNE HILL 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
NF MOKELUMNE R BL SALT SPRINGS DAM 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
MOKELUMNE R A WOODBRIDGE 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
COLE C NR SALT SPRINGS DAM 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
WOODBRIDGE CN A WOODBRIDGE 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
DRY C NR GALT 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	126	yes, 20 or more
Values held	2,925	yes, 1000 or more
Distinct measurements	6	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-11323500.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 Mokelumne gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-mokelumne/

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 Mokelumne 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 confidence2024-10-20

Source: USGS — National Water Information System, USGS site 11323500, 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.