The monitoring network within this area

Hydrionis holds 330 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

330

Values held

1907–2026

Record spans

Gauges within the Upper Green 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 GREEN RIVER AT MUNFORDVILLE, KY

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1915–2025.

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	GREEN RIVER AT MUNFORDVILLE, KY (m³/s)
1915	1,119
1917	889
1918	807
1919	892
1920	1,028
1921	651
1922	606
1924	1,070
1926	544
1927	1,048
1928	682
1929	759
1930	462
1931	340
1932	1,065
1933	895
1934	875
1935	1,271
1936	663
1937	2,044
1938	442
1939	852
1940	614
1941	433
1942	561
1943	1,147
1944	575
1945	1,022
1946	555
1947	595
1948	1,237
1949	1,300
1950	1,215
1951	634
1952	1,589
1953	660
1954	476
1955	991
1956	1,028
1957	895
1959	651
1961	521
1962	2,175
1963	665
1964	1,243
1965	719
1966	450
1967	954
1968	1,068
1969	360
1970	694
1972	674
1974	1,274
1975	1,402
1976	609
1977	518
1978	1,741
1981	629
1982	665
1983	892
1984	1,849
1986	416
1987	663
1988	552
1989	1,266
1990	796
1991	575
1993	377
1994	991
1995	974
1996	459
1997	1,150
1998	634
1999	657
2000	530
2002	629
2003	784
2004	640
2006	609
2007	439
2008	702
2009	770
2010	1,611
2011	841
2013	711
2014	674
2015	728
2017	558
2019	773
2021	1,184
2022	762
2023	623
2024	640
2025	1,427

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	1915–2025
Completeness	84.7% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	16 separate periods inside 1915–2025 hold no value. The longest runs from 1979 to 1980 — 2 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1915 and is not continuous from it: 111 years separate the first value from the last, and 85% 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 GREEN RIVER AT MUNFORDVILLE, KY, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1970–2025.

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	GREEN RIVER AT MUNFORDVILLE, KY (mm)
1970	655
1971	599
1972	952
1973	742
1974	898
1975	909
1976	606
1977	710
1978	822
1979	1,232
1980	386
1981	564
1984	868
1985	462
1990	682
1991	698
1992	581
1993	459
1994	809
1995	748
1996	762
1997	779
1998	821
1999	417
2000	339
2001	347
2002	667
2003	857
2004	889
2005	454
2006	601
2007	452
2008	559
2009	798
2010	602
2011	907
2012	411
2013	792
2014	664
2015	874
2016	630
2017	547
2018	902
2019	891
2020	1,040
2021	744
2022	624
2023	445
2024	594
2025	1,077

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	1970–2025
Completeness	89.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1970–2025 hold no value. The longest runs from 1986 to 1989 — 4 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1970 and is not continuous from it: 56 years separate the first value from the last, and 89% 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 Upper Green and what each holds
Gauge	Measures	Values	Record
GREEN RIVER AT MUNFORDVILLE, KY	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	243	1915–2026
GREEN RIVER AT LOCK 6 AT BROWNSVILLE, KY	catchment area, annual maximum river flow	87	1907–2026

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 — 05110001. 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
GREEN RIVER AT MUNFORDVILLE, KY	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
GREEN RIVER AT LOCK 6 AT BROWNSVILLE, KY	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 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	120	yes, 20 or more
Values held	330	no
Distinct measurements	5	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-03308500.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), Upper Green gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-upper-green/

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 Upper Green 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 confidence2025-04-06

Source: USGS — National Water Information System, USGS site 03308500, 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.