The monitoring network within this area

Hydrionis holds 1,033 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.

2

Gauges

1,033

Values held

1899–2026

Record spans

Gauges within the Middle Milk 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 Milk River at Havre MT

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1917–2025.

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	Milk River at Havre MT (m³/s)
1917	229
1918	259
1919	19.4
1920	116
1921	41.1
1922	94.6
1952	323
1953	195
1955	75.6
1956	36.2
1957	36.2
1958	39.9
1959	56.1
1960	46.2
1961	36.2
1962	33.4
1963	28.6
1964	37.9
1965	165
1966	42.5
1967	119
1968	41.3
1969	99.7
1970	39.6
1971	85.0
1972	48.4
1973	43.9
1974	44.7
1975	104
1976	37.9
1977	34.5
1978	222
1979	96.8
1980	44.5
1981	42.2
1982	46.4
1983	34.8
1984	36.2
1985	37.9
1986	42.8
1987	43.9
1988	43.0
1989	45.0
1990	52.4
1991	51.0
1992	47.3
1993	46.7
1994	215
1995	50.4
1996	152
1997	47.6
1998	38.2
1999	36.0
2000	36.0
2001	36.2
2002	64.8
2003	35.4
2004	36.8
2005	35.7
2006	36.0
2007	27.2
2008	30.3
2009	34.8
2010	137
2011	130
2012	38.8
2013	97.1
2014	52.1
2015	29.4
2016	24.7
2017	34.0
2018	233
2019	36.5
2020	26.6
2021	38.2
2022	32.8
2023	67.7
2024	33.1
2025	26.7

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 exist	Measured
Period held	1917–2025
Completeness	72.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1917–2025 hold no value. The longest runs from 1923 to 1951 — 29 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1917 and is not continuous from it: 109 years separate the first value from the last, and 72% 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 Milk River at Havre 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. 1900–2024.

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	Milk River at Havre MT (mm)
1900	11.0
1901	16.0
1902	37.0
1903	28.0
1904	16.0
1905	2.00
1906	7.00
1907	24.0
1908	25.0
1909	23.0
1910	10.0
1911	18.0
1912	22.0
1913	18.0
1914	9.00
1915	14.0
1916	40.0
1917	35.0
1918	29.0
1919	11.0
1920	29.0
1921	12.0
1955	33.0
1956	31.0
1957	29.0
1958	30.0
1959	34.0
1960	31.0
1961	22.0
1962	21.0
1963	23.0
1964	28.0
1965	51.0
1966	31.0
1967	45.0
1968	32.0
1969	39.0
1970	26.0
1971	32.0
1972	29.0
1973	24.0
1974	27.0
1975	40.0
1976	34.0
1977	17.0
1978	48.0
1979	41.0
1980	25.0
1981	28.0
1982	24.0
1983	17.0
1984	16.0
1985	20.0
1986	29.0
1987	23.0
1988	21.0
1989	28.0
1990	32.0
1991	31.0
1992	21.0
1993	37.0
1994	39.0
1995	26.0
1996	42.0
1997	34.0
1998	27.0
1999	21.0
2000	19.0
2001	13.0
2002	27.0
2003	23.0
2004	19.0
2005	21.0
2010	40.0
2013	29.0
2014	30.0
2015	21.0
2016	22.0
2017	24.0
2018	35.0
2019	20.0
2020	15.0
2021	20.0
2022	22.0
2023	24.0
2024	15.0

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	1900–2024
Completeness	68.8% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	3 separate periods inside 1900–2024 hold no value. The longest runs from 1922 to 1954 — 33 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1900 and is not continuous from it: 125 years separate the first value from the last, and 69% 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

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

231

Fullest snowpack recorded at Rocky Boy, in 1971 (mm of water)

29

Thinnest, in 2005 (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 Rocky Boy

Water years 1968–2026. 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	Rocky Boy (mm)
1968	125
1969	117
1970	191
1971	231
1972	96.0
1973	35.0
1974	160
1975	213
1976	109
1977	101
1978	214
1979	191
1980	121
1981	50.0
1982	167
1983	91.0
1984	136
1985	152
1986	98.0
1987	94.0
1988	125
1989	132
1990	121
1991	128
1992	70.0
1993	132
1994	168
1995	49.0
1996	117
1997	118
1998	90.0
1999	134
2000	88.0
2001	98.0
2002	108
2003	80.0
2004	133
2005	29.0
2006	110
2007	104
2008	113
2009	138
2010	89.0
2011	189
2012	68.0
2013	148
2014	166
2015	107
2016	69.0
2017	74.0
2018	163
2019	165
2020	183
2021	121
2022	82.0
2023	215
2024	62.0
2025	197
2026	56.0

Read against the river

Rocky Boy and Milk River at Havre MT both sit in this drainage area, and their records overlap by 57 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 Middle Milk and what each holds
Gauge	Measures	Values	Record
Milk River at Havre MT	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	292	1899–2026
Milk River at Malta MT	catchment area, annual maximum river flow	33	1903–2026

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 — 10050004. 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
Milk River at Havre 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	2026-10-02
Milk River at Malta 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	2026-10-02

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 4 of them, which makes it a full profile.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	1	no
Years spanned	128	yes, 20 or more
Values held	1,033	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-06140500.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), Middle Milk gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-middle-milk/

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 Middle Milk 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 06140500, 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.