The monitoring network within this area

Hydrionis holds 380 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

380

Values held

1929–2026

Record spans

Gauges within the Apalachicola 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 APALACHICOLA RIVER AT CHATTAHOOCHEE FLA

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1929–2025.

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	APALACHICOLA RIVER AT CHATTAHOOCHEE FLA (m³/s)
1929	8,297
1930	2,025
1932	1,291
1933	2,093
1934	1,795
1935	1,325
1936	4,106
1937	2,110
1938	3,058
1939	2,860
1940	2,002
1941	697
1942	2,803
1943	4,049
1944	4,021
1945	1,651
1946	2,413
1947	2,061
1948	3,426
1950	1,051
1951	1,028
1952	2,475
1953	2,585
1955	1,254
1956	1,866
1957	2,701
1958	2,662
1959	1,846
1960	4,446
1961	3,823
1962	2,206
1963	1,923
1964	4,134
1966	4,644
1967	2,551
1968	2,189
1969	2,325
1970	2,917
1971	3,851
1972	2,917
1973	3,823
1974	2,186
1975	3,936
1976	2,016
1977	2,042
1978	4,927
1979	2,860
1980	3,030
1981	2,263
1982	2,328
1983	2,384
1984	2,243
1985	1,642
1986	1,727
1987	2,302
1988	1,433
1989	1,691
1990	5,125
1991	2,560
1992	1,863
1994	5,833
1995	2,860
1996	2,803
1997	1,841
1998	6,485
2000	1,031
2001	2,832
2002	663
2003	2,549
2004	1,957
2005	4,502
2006	1,424
2007	1,087
2008	1,654
2009	3,766
2011	1,073
2012	988
2013	3,171
2014	3,058
2015	1,611
2017	2,410
2018	1,671
2019	2,738
2020	4,899
2021	1,812
2022	2,294
2023	2,248
2024	3,228
2025	2,161

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	1929–2025
Completeness	91.8% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	8 separate periods inside 1929–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1929 and is not continuous from it: 97 years separate the first value from the last, and 92% 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 APALACHICOLA RIVER AT CHATTAHOOCHEE FLA, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1929–2025.

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	APALACHICOLA RIVER AT CHATTAHOOCHEE FLA (mm)
1929	793
1930	444
1931	281
1932	383
1933	427
1934	303
1935	265
1936	623
1937	521
1938	341
1939	422
1940	382
1941	249
1942	453
1943	482
1944	536
1945	383
1946	564
1947	545
1948	740
1949	586
1950	303
1951	260
1952	386
1953	495
1954	288
1955	225
1956	277
1957	352
1958	405
1959	448
1960	480
1961	494
1962	421
1963	363
1964	805
1965	529
1966	545
1967	439
1968	305
1969	332
1970	390
1971	559
1972	440
1973	647
1974	473
1975	708
1976	536
1977	446
1978	478
1979	480
1980	478
1981	242
1982	443
1983	607
1984	525
1985	303
1986	280
1987	413
1988	276
1989	409
1990	474
1991	473
1992	460
1993	463
1994	628
1995	447
1996	441
1997	472
1998	631
1999	225
2000	188
2001	322
2002	218
2003	533
2004	347
2005	586
2006	262
2007	195
2008	294
2009	574
2010	444
2011	196
2012	153
2013	470
2014	448
2015	406
2016	418
2017	314
2018	444
2019	438
2020	629
2021	485
2022	369
2023	352
2024	474
2025	321

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	1929–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1929 to 2025 is held.
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 Apalachicola and what each holds
Gauge	Measures	Values	Record
APALACHICOLA RIVER AT CHATTAHOOCHEE FLA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	231	1929–2026
APALACHICOLA RIVER NR BLOUNTSTOWN,FLORIDA	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	149	1929–2026

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 — 03130011. 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
APALACHICOLA RIVER AT CHATTAHOOCHEE FLA	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
APALACHICOLA RIVER NR BLOUNTSTOWN,FLORIDA	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	98	yes, 20 or more
Values held	380	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-02358000.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), Apalachicola gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-apalachicola/

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 Apalachicola 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 confidence2025-04-09

Source: USGS — National Water Information System, USGS site 02358000, 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.