HydrionisGlobal Water Intelligence
HUC8 subbasin

Blackfoot

4 monitoring stations within this area in United States, holding 1,835 values between 1903 and 2026. A United States federal hydrologic unit at the eight-digit subbasin level — a drainage area, not a river. Many subbasins take the name of the largest river within them, and the gauges below are anywhere inside the area, including on tributaries.

United StatesHUC8 subbasin

The monitoring network within this area

Hydrionis holds 1,835 values from 4 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.

4
Gauges
1,835
Values held
1903–2026
Record spans
Gauges within the Blackfoot huc8 subbasin
4 monitoring points, positioned as the publisher records them.
Gauges within the Blackfoot huc8 subbasinBLACKFOOT RIVER NR SHELLEY ID, BLACKFOOT RIVER NR BLACKFOOT ID, BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID, BLACKFOOT RIVER AB RESERVOIR NR HENRY IDBLACKFOOT RIVER NR SHELLEY IDBLACKFOOT RIVER NR BLACKFOOT IDBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT IDBLACKFOOT RIVER AB RESERVOIR NR HENRY ID

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 BLACKFOOT RIVER NR SHELLEY ID
The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1903–2025.
Shading marks when something was recorded, not what caused the line.
Largest measured flow of each year at BLACKFOOT RIVER NR SHELLEY IDLargest measured flow of each year at BLACKFOOT RIVER NR SHELLEY ID: BLACKFOOT RIVER NR SHELLEY ID in m³/s, from 1903 to 2025.Hurricane Katrina water and sanitation collapse0255075100m³/s19031916192719391951198820062017

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.

EventTypePeriodStandingAuthority
Hurricane Katrina water and sanitation collapseFlood2005-08-29 – 2005-09-30Documented 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
PeriodBLACKFOOT RIVER NR SHELLEY ID (m³/s)
190327.4
190449.6
190517.2
190638.2
190767.1
190822.4
190955.5
191218.4
191336.2
191428.3
191531.7
191626.2
191730.0
191827.9
191925.7
192035.1
192147.3
192234.5
192351.8
192428.2
192529.2
192639.1
192718.5
192828.1
192939.4
193036.0
193136.5
193330.6
193415.3
193525.1
193630.9
193736.0
193823.2
193935.4
194032.8
194132.0
194235.4
194321.5
194440.8
194525.3
194726.0
194831.1
194934.5
195043.0
195132.8
197657.5
197735.4
197830.9
198031.1
198133.7
198242.5
198357.2
198458.9
198545.3
198791.2
198832.3
198925.2
199128.1
199225.9
199328.0
199429.2
199518.6
199649.8
199749.3
200131.1
200221.7
200630.0
200726.6
200819.6
200918.0
201021.9
201142.2
201227.2
201324.7
201430.9
201519.9
201618.1
201751.3
201831.7
201939.9
202029.7
202131.7
202226.5
202324.4
202465.4
202525.7

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 existMeasured
Period held1903–2025
Completeness69.9% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps
  • 9 separate periods inside 1903–2025 hold no value. The longest runs from 1952 to 1975 — 24 years with no reading. They are drawn as breaks in the line and are never interpolated across.
ContinuityThe record begins in 1903 and is not continuous from it: 123 years separate the first value from the last, and 70% of the years between them are held. The span is not the record.
Last read from the publisher2026-10-01
RedistributionPermitted by the upstream licences
Commercial reusePermitted by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow 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 BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID, as a depth
The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1932–2012.
Shading marks when something was recorded, not what caused the line.
Water leaving the catchment above BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID, as a depthWater leaving the catchment above BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID, as a depth: BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID in mm, from 1932 to 2012.Hurricane Katrina water and sanitation collapse050100150200mm19321946195619661976198619962006BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1932: 31.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1933: 27.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1934: 20.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1935: 17.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1936: 34.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1941: 34.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1942: 37.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1943: 51.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1944: 34.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1945: 55.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1946: 62.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1947: 41.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1948: 48.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1949: 33.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1950: 76.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1951: 79.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1952: 63.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1953: 45.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1954: 35.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1955: 29.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1956: 41.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1957: 58.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1958: 38.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1959: 28.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1960: 24.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1961: 22.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1962: 38.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1963: 37.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1964: 39.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1965: 99.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1966: 35.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1967: 39.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1968: 44.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1969: 68.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1970: 64.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1971: 131 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1972: 140 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1973: 72.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1974: 102 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1975: 105 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1976: 128 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1977: 27.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1978: 50.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1979: 45.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1980: 50.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1981: 39.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1982: 97.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1983: 158 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1984: 188 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1985: 103 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1986: 162 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1987: 54.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1988: 24.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1989: 35.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1990: 28.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1991: 29.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1992: 13.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1993: 46.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1994: 28.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1995: 42.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1996: 61.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1997: 147 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1998: 91.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 1999: 84.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2000: 50.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2001: 18.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2002: 17.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2003: 15.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2004: 20.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2005: 24.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2006: 41.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2007: 30.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2008: 28.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2009: 39.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2010: 28.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2011: 88.0 mmBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID 2012: 46.0 mm

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.

EventTypePeriodStandingAuthority
Hurricane Katrina water and sanitation collapseFlood2005-08-29 – 2005-09-30Documented 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
PeriodBLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT ID (mm)
193231.0
193327.0
193420.0
193517.0
193634.0
194134.0
194237.0
194351.0
194434.0
194555.0
194662.0
194741.0
194848.0
194933.0
195076.0
195179.0
195263.0
195345.0
195435.0
195529.0
195641.0
195758.0
195838.0
195928.0
196024.0
196122.0
196238.0
196337.0
196439.0
196599.0
196635.0
196739.0
196844.0
196968.0
197064.0
1971131
1972140
197372.0
1974102
1975105
1976128
197727.0
197850.0
197945.0
198050.0
198139.0
198297.0
1983158
1984188
1985103
1986162
198754.0
198824.0
198935.0
199028.0
199129.0
199213.0
199346.0
199428.0
199542.0
199661.0
1997147
199891.0
199984.0
200050.0
200118.0
200217.0
200315.0
200420.0
200524.0
200641.0
200730.0
200828.0
200939.0
201028.0
201188.0
201246.0

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 existDerived Computed by Hydrionis
Period held1932–2012
Completeness95.1% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps
  • One period inside 1932–2012 holds no value: 1937 to 1940, 4 years with no reading. It is drawn as a break in the line and is never interpolated across.
ContinuityThe record begins in 1932 and is not continuous from it: 81 years separate the first value from the last, and 95% of the years between them are held. The span is not the record.
Inputs last read2026-10-01 · when the records this was computed from were last read from their publishers
Calculation date2026-08-24 · when the calculation method was last versioned, not a reading of any publisher
RedistributionPermitted by the upstream licences
Commercial reusePermitted by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow this was produced

The snow standing above this water

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

775
Fullest snowpack recorded at Slug Creek Divide, in 1982 (mm of water)
182
Thinnest, in 2001 (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 Slug Creek Divide
Water years 1981–2026. Each point is the fullest month of that snow season.
Peak snowpack at Slug Creek DividePeak snowpack at Slug Creek Divide: Slug Creek Divide in mm, from 1981 to 2026.0200400600800mm19811987199319992005201120172024Slug Creek Divide 1981: 236 mmSlug Creek Divide 1982: 775 mmSlug Creek Divide 1983: 514 mmSlug Creek Divide 1984: 557 mmSlug Creek Divide 1985: 403 mmSlug Creek Divide 1986: 671 mmSlug Creek Divide 1987: 218 mmSlug Creek Divide 1988: 314 mmSlug Creek Divide 1989: 377 mmSlug Creek Divide 1990: 255 mmSlug Creek Divide 1991: 295 mmSlug Creek Divide 1992: 183 mmSlug Creek Divide 1993: 378 mmSlug Creek Divide 1994: 305 mmSlug Creek Divide 1995: 337 mmSlug Creek Divide 1996: 489 mmSlug Creek Divide 1997: 607 mmSlug Creek Divide 1998: 392 mmSlug Creek Divide 1999: 396 mmSlug Creek Divide 2000: 328 mmSlug Creek Divide 2001: 182 mmSlug Creek Divide 2002: 303 mmSlug Creek Divide 2003: 332 mmSlug Creek Divide 2004: 297 mmSlug Creek Divide 2005: 294 mmSlug Creek Divide 2006: 450 mmSlug Creek Divide 2007: 276 mmSlug Creek Divide 2008: 461 mmSlug Creek Divide 2009: 409 mmSlug Creek Divide 2010: 254 mmSlug Creek Divide 2011: 592 mmSlug Creek Divide 2012: 337 mmSlug Creek Divide 2013: 302 mmSlug Creek Divide 2014: 530 mmSlug Creek Divide 2015: 359 mmSlug Creek Divide 2016: 310 mmSlug Creek Divide 2017: 532 mmSlug Creek Divide 2018: 348 mmSlug Creek Divide 2019: 429 mmSlug Creek Divide 2020: 456 mmSlug Creek Divide 2021: 349 mmSlug Creek Divide 2022: 279 mmSlug Creek Divide 2024: 508 mmSlug Creek Divide 2025: 442 mmSlug Creek Divide 2026: 245 mm

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
PeriodSlug Creek Divide (mm)
1981236
1982775
1983514
1984557
1985403
1986671
1987218
1988314
1989377
1990255
1991295
1992183
1993378
1994305
1995337
1996489
1997607
1998392
1999396
2000328
2001182
2002303
2003332
2004297
2005294
2006450
2007276
2008461
2009409
2010254
2011592
2012337
2013302
2014530
2015359
2016310
2017532
2018348
2019429
2020456
2021349
2022279
2024508
2025442
2026245

Read against the river

Slug Creek Divide and BLACKFOOT RIVER NR SHELLEY 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

GaugeMeasuresValuesRecord
BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT IDburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2531919–2026
BLACKFOOT RIVER NR SHELLEY IDburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2491903–2026
BLACKFOOT RIVER NR BLACKFOOT IDburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year1951963–2026
BLACKFOOT RIVER AB RESERVOIR NR HENRY IDcatchment area, annual maximum river flow361914–2026

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 — 17040207. 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.

GaugeEvidenceEstablished
BLACKFOOT RIVER AND BYPASS CHANNEL NR BLACKFOOT IDStated 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/42026-10-02
BLACKFOOT RIVER NR SHELLEY IDStated 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/42026-10-02
BLACKFOOT RIVER NR BLACKFOOT IDStated 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/42026-10-02
BLACKFOOT RIVER AB RESERVOIR NR HENRY IDStated 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/42026-10-02

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.

SignalHeldCounts
Gauges holding a real record3yes, 3 or more
Years spanned124yes, 20 or more
Values held1,835yes, 1000 or more
Distinct measurements6yes, 2 or more
Publishers measuring it2yes, 2 or more
Official identifiers1recorded, not counted

Use this data

Use this data

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), Blackfoot gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-blackfoot/

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 Blackfoot 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 confidence2015-10-15

Source: USGS — National Water Information System, USGS site 13068501, 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.

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