The monitoring network within this area

Hydrionis holds 1,719 values from 5 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.

5

Gauges

1,719

Values held

1909–2026

Record spans

Gauges within the Lake Walcott huc8 subbasin

5 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 SNAKE R NR MINIDOKA ID AT HOWELLS FERRY

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	SNAKE R NR MINIDOKA ID AT HOWELLS FERRY (m³/s)
1914	1,031
1916	685
1917	988
1918	1,300
1919	402
1920	629
1921	932
1922	801
1923	612
1925	705
1926	255
1927	909
1928	748
1929	425
1931	230
1932	251
1934	208
1937	385
1939	377
1940	251
1941	241
1942	572
1943	847
1944	674
1945	665
1946	716
1947	765
1948	702
1949	405
1950	759
1951	603
1952	600
1953	609
1954	510
1955	297
1956	767
1957	705
1958	357
1959	300
1960	292
1961	261
1962	510
1963	719
1964	807
1965	538
1966	280
1967	515
1968	532
1969	589
1970	606
1971	801
1972	620
1973	402
1974	612
1975	547
1976	702
1978	368
1979	518
1980	708
1981	603
1982	648
1983	739
1984	748
1985	572
1986	733
1988	286
1989	306
1990	292
1993	549
1996	580
1997	1,215
2000	328
2001	262
2006	614
2007	303
2008	362
2009	665
2010	309
2011	787
2012	382
2013	309
2014	374
2015	326
2016	365
2017	697
2018	583
2019	595
2020	408
2021	385
2022	278
2023	365
2024	538
2025	379

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	83.0% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	12 separate periods inside 1914–2025 hold no value. The longest runs from 2002 to 2005 — 4 years with no reading. 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 83% 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 SNAKE R NR MINIDOKA ID AT HOWELLS FERRY, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1911–2025.

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	SNAKE R NR MINIDOKA ID AT HOWELLS FERRY (mm)
1911	204
1912	239
1913	237
1914	203
1915	122
1916	193
1917	227
1918	203
1919	108
1920	144
1921	185
1922	158
1923	155
1924	88.0
1925	176
1926	97.0
1927	151
1928	183
1929	130
1930	103
1931	86.0
1932	90.0
1933	93.0
1934	70.0
1935	75.0
1936	101
1937	93.0
1938	121
1939	116
1940	87.0
1941	86.0
1942	108
1943	180
1944	118
1945	135
1946	159
1947	138
1948	149
1949	139
1950	175
1951	192
1952	182
1953	129
1954	124
1955	108
1956	169
1957	141
1958	117
1959	98.0
1960	97.0
1961	74.0
1962	120
1963	119
1964	144
1965	187
1966	127
1967	118
1968	124
1969	154
1970	153
1971	268
1972	237
1973	148
1974	209
1975	208
1976	227
1977	93.0
1978	123
1979	137
1980	134
1981	126
1982	207
1983	257
1984	273
1985	176
1986	261
1987	108
1988	83.0
1989	94.0
1990	92.0
1991	90.0
1992	79.0
1993	102
1994	109
1995	122
1996	200
1997	313
1998	207
1999	209
2000	130
2001	84.0
2002	81.0
2003	81.0
2004	74.0
2005	77.0
2006	124
2007	96.0
2008	93.0
2009	138
2010	101
2011	232
2012	126
2013	88.0
2014	95.0
2015	101
2016	87.0
2017	194
2018	190
2019	135
2020	127
2021	94.0
2022	78.0
2023	90.0
2024	116
2025	96.0

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	1911–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1911 to 2025 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.

1,170

Fullest snowpack recorded at Howell Canyon, in 2006 (mm of water)

197

Thinnest, in 1981 (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 Howell Canyon

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	Howell Canyon (mm)
1981	197
1982	993
1983	840
1984	953
1985	472
1986	932
1987	311
1988	436
1989	639
1990	302
1991	411
1992	319
1993	864
1994	327
1995	537
1996	741
1997	1,116
1998	796
1999	708
2000	633
2001	317
2002	656
2003	351
2004	649
2005	557
2006	1,170
2007	636
2008	791
2009	690
2010	562
2011	938
2012	577
2013	599
2014	704
2015	659
2016	807
2017	945
2018	570
2019	715
2020	591
2021	612
2022	642
2023	864
2024	824
2025	674
2026	435

Read against the river

Howell Canyon and SNAKE RIVER AT NEELEY ID 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 Lake Walcott and what each holds
Gauge	Measures	Values	Record
SNAKE R NR MINIDOKA ID AT HOWELLS FERRY	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	365	1910–2026
SNAKE RIVER AT NEELEY ID	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	324	1914–2026
SOUTH SIDE MINIDOKA CANAL NR MINIDOKA ID	burned area within 50 km, mean river flow, mean river flow, water year	166	1909–2019
SOUTH SIDE TWIN FALLS CANAL AT MILNER ID	burned area within 50 km, mean river flow, mean river flow, water year	165	1909–2019
P A LATERAL NR MILNER ID	burned area within 50 km, mean river flow, mean river flow, water year	147	1919–2019

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 — 17040209. 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
SNAKE R NR MINIDOKA ID AT HOWELLS FERRY	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
SNAKE RIVER AT NEELEY ID	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
SOUTH SIDE MINIDOKA CANAL NR MINIDOKA ID	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
SOUTH SIDE TWIN FALLS CANAL AT MILNER ID	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
P A LATERAL NR MILNER ID	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	5	yes, 3 or more
Years spanned	118	yes, 20 or more
Values held	1,719	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-13081500.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), Lake Walcott gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-lake-walcott/

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 Lake Walcott 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 confidence2025-06-23

Source: USGS — National Water Information System, USGS site 13081500, 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.