The monitoring network within this area

Hydrionis holds 322 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

322

Values held

1904–2026

Record spans

Gauges within the Lower Elk 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 ELK RIVER AT PROSPECT, TN

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1906–2025.

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	ELK RIVER AT PROSPECT, TN (m³/s)
1906	691
1907	646
1919	841
1920	1,402
1921	1,175
1922	1,175
1923	850
1924	991
1925	351
1926	1,730
1928	739
1929	2,308
1930	702
1931	445
1932	745
1933	903
1934	1,192
1935	799
1936	847
1937	1,223
1938	456
1939	1,186
1940	501
1941	459
1942	479
1944	1,229
1945	1,303
1946	1,320
1947	883
1948	2,832
1949	1,662
1950	1,339
1951	1,591
1952	1,068
1953	906
1954	1,235
1955	2,945
1956	1,036
1957	1,858
1959	493
1961	1,631
1962	1,130
1963	1,722
1964	980
1965	1,059
1966	481
1967	917
1968	765
1969	773
1971	784
1972	606
1973	3,313
1974	2,254
1975	2,390
1977	1,220
1978	971
1979	966
1980	1,444
1981	300
1982	782
1983	1,563
1984	900
1986	490
1988	572
1989	1,322
1991	2,917
1993	657
1994	1,555
2003	247
2004	1,464
2006	1,002
2007	476
2008	609
2010	895
2011	1,158
2012	558
2013	705
2014	572
2015	617
2017	354
2018	1,320
2019	2,212
2020	1,186
2021	1,093
2022	1,152
2023	671
2024	719
2025	1,286

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	1906–2025
Completeness	73.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	15 separate periods inside 1906–2025 hold no value. The longest runs from 1908 to 1918 — 11 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1906 and is not continuous from it: 120 years separate the first value from the last, and 73% 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 ELK RIVER NEAR PROSPECT, TN, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1905–1989.

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 (0 events)

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	ELK RIVER NEAR PROSPECT, TN (mm)
1905	535
1906	523
1907	479
1920	913
1921	535
1922	804
1923	744
1924	556
1925	314
1926	617
1927	633
1928	626
1929	933
1930	392
1931	314
1932	742
1933	646
1934	407
1935	462
1936	587
1937	664
1938	479
1939	701
1940	360
1941	257
1942	374
1943	344
1944	600
1945	660
1946	724
1947	483
1948	738
1949	741
1950	880
1951	758
1952	473
1953	513
1954	436
1955	640
1956	520
1957	817
1958	507
1959	514
1960	456
1961	687
1962	711
1963	517
1964	767
1965	479
1966	356
1967	672
1968	487
1969	489
1970	568
1971	466
1972	688
1973	987
1974	876
1975	952
1976	505
1977	789
1978	448
1979	870
1980	590
1981	212
1982	568
1983	830
1984	586
1985	340
1986	463
1987	345
1988	315
1989	993

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	1905–1989
Completeness	85.9% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	One period inside 1905–1989 holds no value: 1908 to 1919, 12 years with no reading. It is drawn as a break in the line and is never interpolated across.
Continuity	The record begins in 1905 and is not continuous from it: 85 years separate the first value from the last, and 86% 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 Elk and what each holds
Gauge	Measures	Values	Record
ELK RIVER NEAR PROSPECT, TN	catchment area, annual maximum river flow, mean river flow, mean river flow, water year	220	1904–2026
ELK RIVER AT PROSPECT, TN	catchment area, annual maximum river flow	102	1906–2026

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 — 06030004. 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
ELK RIVER NEAR PROSPECT, TN	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
ELK RIVER AT PROSPECT, TN	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	123	yes, 20 or more
Values held	322	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-03584500.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 Elk gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-lower-elk/

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 Elk 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 confidence1989-03-06

Source: USGS — National Water Information System, USGS site 03584500, 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.