The monitoring network within this area

Hydrionis holds 349 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

349

Values held

1923–2026

Record spans

Gauges within the Blackwater 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 Blackwater River at Blue Lick, MO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1923–2025.

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	Blackwater River at Blue Lick, MO (m³/s)
1923	263
1924	306
1925	200
1926	283
1927	493
1928	1,529
1930	226
1931	90.6
1933	195
1938	555
1939	278
1940	150
1941	110
1942	379
1943	790
1944	917
1945	357
1946	320
1947	365
1948	442
1949	276
1951	677
1953	167
1954	93.2
1955	146
1957	89.2
1958	229
1959	101
1960	459
1961	850
1962	306
1963	97.7
1964	150
1965	736
1966	197
1967	328
1968	255
1969	549
1970	382
1971	255
1972	161
1973	1,000
1974	592
1975	294
1976	151
1977	433
1979	416
1980	153
1981	289
1982	340
1983	629
1984	345
1985	776
1986	1,269
1988	183
1989	126
1990	878
1991	212
1992	180
1993	541
1994	748
1995	586
1996	428
1997	428
1998	677
2000	306
2001	549
2002	558
2003	242
2004	252
2005	459
2006	156
2007	578
2008	413
2009	447
2010	464
2011	343
2012	323
2013	617
2014	374
2015	436
2016	487
2017	558
2018	227
2019	445
2020	462
2021	396
2022	280
2023	153
2024	379
2025	394

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	1923–2025
Completeness	88.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	9 separate periods inside 1923–2025 hold no value. The longest runs from 1934 to 1937 — 4 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1923 and is not continuous from it: 103 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	2026-08-31
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 Blackwater River at Blue Lick, 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. 1923–2025.

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	Blackwater River at Blue Lick, MO (mm)
1923	163
1924	167
1925	104
1926	241
1927	442
1928	316
1929	438
1930	50.0
1931	84.0
1932	97.0
1939	76.0
1940	84.0
1941	200
1942	360
1943	228
1944	350
1945	319
1946	176
1947	360
1948	291
1949	358
1950	180
1951	548
1952	149
1953	68.0
1954	43.0
1955	110
1956	17.0
1957	75.0
1958	206
1959	74.0
1960	227
1961	596
1962	181
1963	34.0
1964	110
1965	463
1966	94.0
1967	249
1968	187
1969	539
1970	297
1971	125
1972	91.0
1973	541
1974	311
1975	222
1976	84.0
1977	221
1978	164
1979	104
1980	58.0
1981	226
1982	419
1983	327
1984	410
1985	673
1986	534
1987	187
1988	77.0
1989	69.0
1990	424
1991	97.0
1992	238
1993	678
1994	361
1995	423
1996	243
1997	266
1998	632
1999	315
2000	115
2001	437
2002	209
2003	100
2004	344
2005	251
2006	59.0
2007	232
2008	546
2009	531
2010	585
2011	333
2012	117
2013	313
2014	193
2015	406
2017	334
2018	105
2019	416
2020	359
2021	379
2022	143
2023	49.0
2024	197
2025	143

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	1923–2025
Completeness	93.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1923–2025 hold no value. The longest runs from 1933 to 1938 — 6 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1923 and is not continuous from it: 103 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 Blackwater and what each holds
Gauge	Measures	Values	Record
Blackwater River at Blue Lick, MO	catchment area, annual maximum river flow, mean river flow	196	1923–2026
BLACKWATER RIVER NEAR BRADLEY AL	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	153	1967–2026

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 — 03140104. 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
Blackwater River at Blue Lick, 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	2026-08-26
BLACKWATER RIVER NEAR BRADLEY AL	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	104	yes, 20 or more
Values held	349	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-06908000.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), Blackwater gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-blackwater/

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 Blackwater 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 confidence2025-04-23

Source: USGS — National Water Information System, USGS site 06908000, 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.