The monitoring network within this area

Hydrionis holds 780 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.

Gauges

780

Values held

1921–2026

Record spans

Gauges within the Lower Grand 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 Grand River near Sumner, MO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1924–2025.

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	Grand River near Sumner, MO (m³/s)
1924	1,036
1925	934
1926	1,597
1927	1,354
1928	1,328
1929	3,115
1930	515
1931	1,008
1932	646
1935	2,039
1936	1,161
1937	1,042
1938	230
1939	1,283
1940	510
1941	1,288
1942	2,546
1943	1,716
1944	3,256
1945	2,441
1946	2,529
1947	5,097
1948	1,727
1949	1,529
1950	997
1951	1,699
1952	1,617
1953	1,674
1954	674
1955	1,297
1956	912
1957	637
1958	2,534
1960	2,945
1961	1,858
1963	1,557
1964	1,280
1965	2,189
1966	663
1967	2,888
1968	1,481
1969	2,124
1970	2,322
1971	943
1972	1,014
1973	2,112
1975	881
1976	1,855
1977	963
1978	2,138
1979	3,370
1980	844
1981	1,841
1982	1,909
1983	1,489
1984	2,206
1985	1,642
1987	1,869
1989	1,178
1990	1,419
1991	2,169
1992	2,053
1993	4,701
1994	1,042
1995	2,277
1997	2,308
1998	2,178
2000	1,000
2001	2,112
2002	2,056
2003	179
2004	4,163
2005	1,620
2006	677
2007	2,832
2008	2,676
2009	2,231
2010	2,407
2011	1,501
2012	1,141
2013	2,424
2014	2,246
2015	2,212
2017	2,551
2018	648
2019	3,087
2021	1,249
2023	1,475
2024	1,926
2025	1,181

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	1924–2025
Completeness	88.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	11 separate periods inside 1924–2025 hold no value. The longest runs from 1933 to 1934 — 2 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1924 and is not continuous from it: 102 years separate the first value from the last, and 88% 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 Grand River near Sumner, MO, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1925–2025.

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	Grand River near Sumner, MO (mm)
1925	168
1926	319
1927	216
1928	328
1929	369
1930	81.0
1931	255
1932	195
1933	64.0
1934	64.0
1935	286
1936	75.0
1937	140
1938	24.0
1939	97.0
1940	56.0
1941	153
1942	265
1943	193
1944	248
1945	318
1946	192
1947	452
1948	109
1949	158
1950	125
1951	291
1952	156
1953	96.0
1954	51.0
1955	83.0
1956	36.0
1957	50.0
1958	256
1959	283
1960	320
1961	420
1962	242
1963	93.0
1964	113
1965	263
1966	63.0
1967	219
1968	90.0
1969	288
1970	219
1971	105
1972	125
1973	595
1974	195
1975	130
1976	115
1977	165
1978	320
1979	240
1980	97.0
1981	161
1982	446
1983	198
1984	295
1985	202
1986	330
1987	262
1988	39.0
1989	40.0
1990	221
1991	234
1992	370
1993	782
1994	104
1995	334
1996	272
1997	216
1998	413
1999	204
2000	35.0
2001	320
2002	99.0
2003	32.0
2004	368
2005	121
2006	41.0
2007	236
2008	571
2009	450
2010	537
2011	187
2012	95.0
2013	193
2014	231
2015	415
2016	231
2017	191
2018	151
2019	590
2021	266
2022	126
2023	98.0
2024	158
2025	135

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	1925–2025
Completeness	99.0% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1925–2025 holds no value: 2020. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1925 and is not continuous from it: 101 years separate the first value from the last, and 99% 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

Every gauge Hydrionis holds within this area

Gauges within the Lower Grand and what each holds
Gauge	Measures	Values	Record
Grand River near Sumner, MO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	335	1924–2026
Locust Creek near Linneus, MO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	247	1929–2026
Medicine Creek near Galt, MO	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	198	1921–2026

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 — 10280103. 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
Grand River near Sumner, MO	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
Locust Creek near Linneus, MO	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
Medicine Creek near Galt, MO	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	3	yes, 3 or more
Years spanned	106	yes, 20 or more
Values held	780	no
Distinct measurements	5	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-06902000.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), Lower Grand gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-lower-grand/

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 Lower Grand 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 confidence2025-06-26

Source: USGS — National Water Information System, USGS site 06902000, 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.