The monitoring network within this area

Hydrionis holds 472 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

472

Values held

1897–2026

Record spans

Gauges within the Hiwassee 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 VALLEY RIVER AT TOMOTLA, NC

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1905–2025.

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	VALLEY RIVER AT TOMOTLA, NC (m³/s)
1905	97.1
1906	75.3
1908	64.8
1909	110
1914	113
1915	103
1917	215
1918	115
1920	183
1922	205
1924	57.5
1926	60.0
1928	143
1929	103
1931	53.8
1932	103
1934	147
1935	82.1
1936	229
1937	100
1938	91.7
1939	94.3
1940	40.8
1941	25.9
1942	68.0
1944	110
1945	81.3
1946	158
1947	174
1948	89.2
1950	155
1951	196
1953	108
1954	183
1955	109
1956	106
1957	236
1958	86.9
1959	85.5
1961	122
1963	193
1964	165
1965	155
1966	189
1967	71.9
1969	161
1971	105
1972	105
1973	111
1975	184
1976	125
1977	174
1978	74.5
1979	217
1980	248
1981	57.5
1982	174
1984	151
1985	84.4
1986	45.3
1987	81.6
1988	87.8
1989	104
1990	269
1991	77.6
1992	142
1994	337
1995	343
1996	168
1997	177
1998	88.9
1999	101
2000	68.0
2001	61.2
2002	89.8
2003	170
2004	69.7
2006	60.0
2007	43.0
2008	49.0
2009	147
2011	68.0
2012	53.2
2013	200
2014	120
2015	212
2017	51.3
2018	115
2019	129
2020	215
2021	123
2022	191
2023	93.7
2024	108
2025	106

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	1905–2025
Completeness	78.5% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	23 separate periods inside 1905–2025 hold no value. The longest runs from 1910 to 1913 — 4 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1905 and is not continuous from it: 121 years separate the first value from the last, and 79% 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 VALLEY RIVER AT TOMOTLA, NC, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1905–2025.

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	VALLEY RIVER AT TOMOTLA, NC (mm)
1905	899
1906	1,335
1907	985
1908	810
1909	1,102
1915	680
1916	811
1919	743
1920	1,253
1921	933
1922	1,189
1923	978
1924	732
1925	506
1926	757
1927	901
1928	1,090
1929	1,329
1930	591
1931	528
1932	1,147
1933	738
1934	616
1935	621
1936	977
1937	729
1938	870
1939	703
1940	475
1941	396
1942	825
1943	791
1944	802
1945	704
1946	841
1947	695
1948	831
1949	1,133
1950	982
1951	773
1952	700
1953	668
1954	682
1955	669
1956	783
1957	1,090
1958	744
1959	741
1960	670
1961	981
1962	970
1963	891
1964	1,085
1965	795
1966	802
1967	1,029
1968	683
1969	703
1970	562
1971	935
1972	1,084
1973	1,009
1974	1,119
1975	1,004
1976	933
1977	904
1978	656
1979	1,194
1980	943
1981	515
1982	1,045
1983	765
1984	857
1985	532
1986	498
1987	621
1988	413
1989	1,325
1990	1,121
1991	1,001
1992	949
1993	732
1994	1,278
1995	917
1996	1,104
1997	988
1998	817
1999	742
2000	508
2001	554
2002	881
2003	1,072
2004	828
2005	746
2006	550
2007	371
2008	502
2009	1,081
2010	733
2011	730
2012	644
2013	1,276
2014	694
2015	942
2016	535
2017	575
2018	1,033
2019	1,240
2020	1,309
2021	1,054
2022	969
2023	898
2024	690
2025	795

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	1905–2025
Completeness	94.2% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1905–2025 hold no value. The longest runs from 1910 to 1914 — 5 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1905 and is not continuous from it: 121 years separate the first value from the last, and 94% 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 Hiwassee and what each holds
Gauge	Measures	Values	Record
VALLEY RIVER AT TOMOTLA, NC	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	266	1905–2026
HIWASSEE RIVER ABOVE MURPHY, NC	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	206	1897–2026

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 — 06020002. 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
VALLEY RIVER AT TOMOTLA, NC	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
HIWASSEE RIVER ABOVE MURPHY, NC	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	130	yes, 20 or more
Values held	472	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-03550000.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), Hiwassee gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-hiwassee/

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 Hiwassee 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 confidence2025-04-07

Source: USGS — National Water Information System, USGS site 03550000, 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.