The monitoring network within this area

Hydrionis holds 3,272 values from 3 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.

3

Gauges

3,272

Values held

1902–2026

Record spans

Gauges within the West Walker huc8 subbasin

3 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 W WALKER RV NR COLEVILLE, CA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1916–2025.

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	W WALKER RV NR COLEVILLE, CA (m³/s)
1916	51.8
1917	68.0
1918	64.6
1919	61.7
1920	42.5
1921	76.7
1922	74.8
1923	50.1
1924	24.2
1925	47.0
1926	40.5
1927	66.5
1928	41.9
1929	38.8
1930	41.1
1931	24.6
1932	57.2
1933	60.0
1934	21.2
1935	55.2
1936	43.6
1937	62.3
1957	56.6
1958	63.1
1959	25.0
1960	36.0
1961	24.6
1962	42.5
1963	71.1
1964	29.2
1966	31.1
1967	80.4
1968	37.7
1969	91.2
1970	43.6
1971	56.4
1972	46.7
1973	62.3
1974	56.1
1975	69.4
1976	24.5
1977	16.5
1978	54.1
1979	63.7
1980	75.0
1981	33.1
1982	63.4
1983	100
1984	58.6
1985	34.8
1986	93.4
1987	28.9
1988	21.7
1989	32.6
1990	17.5
1991	51.0
1992	22.5
1993	56.9
1994	35.4
1995	125
1996	114
1997	354
1998	77.3
1999	77.9
2000	54.9
2001	48.7
2002	41.6
2003	96.3
2004	39.6
2005	97.4
2006	114
2007	23.1
2008	47.6
2009	51.3
2010	116
2011	104
2012	26.2
2013	32.0
2014	19.8
2015	17.2
2016	42.5
2017	124
2018	106
2019	95.1
2020	30.3
2021	23.2
2023	106
2024	47.0
2025	39.9

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	1916–2025
Completeness	80.9% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	3 separate periods inside 1916–2025 hold no value. The longest runs from 1938 to 1956 — 19 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1916 and is not continuous from it: 110 years separate the first value from the last, and 81% 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 W WALKER RV NR COLEVILLE, 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. 1903–2025.

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	W WALKER RV NR COLEVILLE, CA (mm)
1903	429
1904	539
1905	298
1906	808
1907	938
1916	496
1917	470
1918	392
1919	325
1920	331
1921	420
1922	513
1923	409
1924	118
1925	388
1926	242
1927	456
1928	251
1929	207
1930	257
1931	134
1932	388
1933	228
1934	185
1935	371
1936	385
1958	519
1959	211
1960	199
1961	170
1962	358
1963	441
1964	251
1965	459
1966	265
1967	589
1968	256
1969	724
1970	350
1971	367
1972	288
1973	426
1974	445
1975	445
1976	151
1977	98.0
1978	487
1979	381
1980	560
1981	242
1982	656
1983	772
1984	480
1985	286
1986	604
1987	177
1988	175
1989	296
1990	177
1991	261
1992	174
1993	488
1994	197
1995	763
1996	533
1997	667
1998	628
1999	475
2000	350
2001	255
2002	287
2003	378
2004	288
2005	547
2006	696
2007	187
2008	259
2009	344
2010	460
2011	671
2012	170
2013	213
2014	137
2015	149
2016	339
2017	936
2018	361
2019	536
2020	176
2021	189
2022	232
2023	879
2024	309
2025	291

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	1903–2025
Completeness	76.4% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1903–2025 hold no value. The longest runs from 1937 to 1957 — 21 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1903 and is not continuous from it: 123 years separate the first value from the last, and 76% 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

The snow standing above this water

5 automated snow stations sit inside this drainage area, weighing the snowpack rather than measuring how deep it is.

1,295

Fullest snowpack recorded at Lobdell Lake, in 2023 (mm of water)

101

Thinnest, in 2007 (mm of water)

March

Month the pack is usually at its fullest

May

Month the pack has gone by, in half of years

Peak snowpack at Lobdell Lake

Water years 1979–2026. 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	Lobdell Lake (mm)
1979	393
1980	556
1981	259
1982	751
1983	1,044
1984	450
1985	321
1986	681
1987	218
1988	184
1989	310
1990	215
1991	264
1992	253
1993	504
1994	200
1995	834
1996	494
1997	713
1998	618
1999	416
2000	312
2001	252
2002	303
2003	473
2004	387
2005	728
2006	806
2007	101
2008	487
2009	283
2010	432
2011	773
2012	134
2013	282
2014	161
2015	112
2016	390
2017	989
2018	267
2019	741
2020	165
2021	223
2022	245
2023	1,295
2024	340
2025	319
2026	225

Read against the river

Lobdell Lake and W WALKER RV NR COLEVILLE, CA both sit in this drainage area, and their records overlap by 46 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 West Walker and what each holds
Gauge	Measures	Values	Record
W WALKER RV NR COLEVILLE, CA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	319	1902–2026
W WALKER RV AT HOYE BRG NR WELLINGTON, NV	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	269	1920–2026
W WALKER RV NR HUDSON, NV	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	260	1914–2026

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 — 16050302. 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
W WALKER RV NR COLEVILLE, 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
W WALKER RV AT HOYE BRG NR WELLINGTON, NV	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
W WALKER RV NR HUDSON, NV	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	3	yes, 3 or more
Years spanned	125	yes, 20 or more
Values held	3,272	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-10296500.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), West Walker gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-west-walker/

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 West Walker 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 confidence2025-05-31

Source: USGS — National Water Information System, USGS site 10296500, 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.