The monitoring network within this area

Hydrionis holds 366 values from 2 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

366

Values held

1911–2026

Record spans

Gauges within the Stillwater huc8 subbasin

2 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 Stillwater River near Absarokee, MT

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1911–2024.

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	Stillwater River near Absarokee, MT (m³/s)
1911	206
1912	177
1913	172
1914	172
1935	202
1936	146
1937	211
1938	134
1939	114
1940	148
1941	114
1942	241
1943	260
1944	278
1945	212
1946	144
1947	203
1948	300
1949	150
1950	196
1951	155
1952	225
1953	198
1954	193
1955	123
1956	244
1957	246
1958	158
1959	208
1960	109
1961	118
1962	191
1963	222
1964	202
1965	180
1966	141
1967	340
1968	195
1969	150
1970	292
1971	245
1972	182
1973	213
1974	328
1975	320
1976	157
1977	117
1978	181
1979	151
1980	184
1981	183
1982	221
1983	242
1984	199
1985	185
1986	156
1987	91.5
1988	161
1989	170
1990	176
1991	255
1992	236
1993	127
1994	123
1995	233
1996	229
1997	249
1998	149
1999	177
2000	133
2001	98.5
2002	200
2003	202
2004	129
2005	174
2006	140
2007	109
2008	181
2009	161
2010	204
2011	282
2012	179
2013	180
2014	205
2015	179
2016	160
2017	244
2018	215
2019	229
2020	260
2021	223
2022	479
2023	165
2024	217

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	1911–2024
Completeness	82.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1911–2024 holds no value: 1915 to 1934, 20 years with no reading. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1911 and is not continuous from it: 114 years separate the first value from the last, and 82% of the years between them are held. The span is not the record.
Last read from the publisher	2026-08-31
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 Stillwater River near Absarokee, MT, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1936–2024.

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	Stillwater River near Absarokee, MT (mm)
1936	187
1937	282
1938	308
1939	209
1940	280
1941	325
1942	390
1943	524
1944	436
1945	393
1946	299
1947	409
1948	394
1949	304
1950	364
1951	359
1952	390
1953	296
1954	299
1955	243
1956	365
1957	488
1958	325
1959	350
1960	214
1961	245
1962	390
1963	367
1964	331
1965	411
1966	285
1967	481
1968	402
1969	335
1970	439
1971	453
1972	410
1973	369
1974	465
1975	546
1976	456
1977	218
1978	388
1979	303
1980	375
1981	322
1982	376
1983	390
1984	399
1985	237
1986	309
1987	244
1988	249
1989	318
1990	294
1991	379
1992	348
1993	337
1994	260
2001	208
2002	286
2003	293
2004	248
2005	296
2006	257
2007	251
2008	338
2009	377
2010	313
2011	482
2012	266
2013	297
2014	487
2015	326
2016	265
2017	413
2018	480
2019	472
2020	357
2021	250
2022	386
2023	407
2024	295

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	1936–2024
Completeness	93.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1936–2024 holds no value: 1995 to 2000, 6 years with no reading. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1936 and is not continuous from it: 89 years separate the first value from the last, and 93% of the years between them are held. The span is not the record.
Last read from the publisher	2026-08-24
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 Stillwater and what each holds
Gauge	Measures	Values	Record
Stillwater River near Absarokee, MT	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	214	1911–2026
Whitefish River near Kalispell MT	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	152	1929–2026

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 — 10070005. 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
Stillwater River near Absarokee, MT	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	2026-08-26
Whitefish River near Kalispell MT	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	2026-08-26

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 3 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	116	yes, 20 or more
Values held	366	no
Distinct measurements	4	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-06205000.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), Stillwater gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-stillwater/

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 Stillwater 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 confidence2024-06-11

Source: USGS — National Water Information System, USGS site 06205000, 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 31 August 2026.