The monitoring network within this area

Hydrionis holds 336 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

336

Values held

1916–2026

Record spans

Gauges within the Lower Clear Fork Brazos 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 Clear Fk Brazos Rv at Ft Griffin, TX

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	Clear Fk Brazos Rv at Ft Griffin, TX (m³/s)
1924	144
1925	193
1926	354
1927	143
1928	343
1929	162
1930	728
1932	951
1933	96.6
1935	527
1936	408
1937	85.2
1938	408
1939	262
1940	245
1941	518
1942	182
1944	102
1945	151
1946	221
1947	236
1949	140
1950	105
1951	85.5
1952	36.8
1953	487
1954	191
1955	487
1956	117
1957	858
1958	166
1959	158
1960	187
1961	197
1962	501
1963	164
1964	30.3
1965	201
1966	218
1967	24.6
1968	157
1969	405
1970	58.0
1971	303
1972	52.1
1974	185
1975	210
1976	67.7
1978	4,219
1979	162
1980	113
1982	267
1983	38.5
1985	88.6
1986	178
1988	69.9
1989	50.1
1990	391
1991	240
1992	481
1993	77.0
1994	181
1995	218
1996	42.2
1997	153
1998	73.1
1999	50.4
2000	62.9
2001	88.9
2002	148
2003	138
2004	174
2005	470
2006	85.2
2007	286
2008	69.4
2009	69.9
2010	174
2012	1.44
2013	27.0
2014	12.0
2015	399
2016	297
2017	221
2018	134
2020	320
2021	561
2022	38.5
2023	79.0
2024	62.0
2025	306

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	89.2% 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. 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 89% 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 Clear Fk Brazos Rv at Ft Griffin, TX, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1939–2025.

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	Clear Fk Brazos Rv at Ft Griffin, TX (mm)
1939	19.0
1940	21.0
1941	82.0
1942	15.0
1943	5.00
1944	8.00
1945	19.0
1946	11.0
1947	18.0
1948	8.00
1949	9.00
1950	10.0
1951	8.00
1952	1.00
1953	14.0
1954	7.00
1955	20.0
1956	1.00
1957	102
1958	8.00
1959	12.0
1960	8.00
1961	26.0
1962	32.0
1963	8.00
1964	1.00
1965	14.0
1966	13.0
1967	3.00
1968	12.0
1969	21.0
1970	5.00
1971	27.0
1972	10.0
1973	10.0
1974	23.0
1975	13.0
1976	7.00
1977	6.00
1978	47.0
1979	8.00
1980	30.0
1981	19.0
1982	34.0
1983	6.00
1984	4.00
1985	17.0
1986	33.0
1987	31.0
1988	6.00
1989	5.00
1990	35.0
1991	42.0
1992	69.0
1993	9.00
1994	12.0
1995	10.0
1996	5.00
1997	14.0
1998	2.00
1999	3.00
2000	5.00
2001	5.00
2002	10.0
2003	6.00
2004	11.0
2005	24.0
2006	3.00
2007	34.0
2008	8.00
2009	3.00
2010	14.0
2011	1.00
2012	1.00
2013	2.00
2014	1.00
2015	24.0
2016	35.0
2017	10.0
2018	59.0
2019	57.0
2020	23.0
2021	35.0
2022	2.00
2023	8.00
2024	6.00
2025	26.0

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	1939–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1939 to 2025 is held.
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 Clear Fork Brazos and what each holds
Gauge	Measures	Values	Record
Clear Fk Brazos Rv at Ft Griffin, TX	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	277	1924–2026
Clear Fk Brazos Rv at Eliasville, TX	catchment area, annual maximum river flow	59	1916–2026

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 — 12060104. 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
Clear Fk Brazos Rv at Ft Griffin, TX	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
Clear Fk Brazos Rv at Eliasville, TX	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 2 of them, which makes it a profile, not indexed.

Information-gain signals held for this water body
Signal	Held	Counts
Gauges holding a real record	2	no
Years spanned	111	yes, 20 or more
Values held	336	no
Distinct measurements	4	yes, 2 or more
Publishers measuring it	1	no
Official identifiers	1	recorded, not counted

Use this data

Machine-readable JSON /api/v1/observations/by-subject/gauge-usgs-08085500.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 Clear Fork Brazos gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-lower-clear-fork-brazos/

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 Clear Fork Brazos 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 confidence2025-05-01

Source: USGS — National Water Information System, USGS site 08085500, 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.