The monitoring network within this area

Hydrionis holds 812 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.

2

Gauges

812

Values held

1923–2026

Record spans

Gauges within the San Luis 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 KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1923–2007.

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	KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO (m³/s)
1923	2.15
1924	6.14
1925	1.22
1926	3.68
1936	8.66
1938	4.47
1939	2.55
1940	1.39
1941	11.5
1942	8.24
1943	2.15
1944	3.40
1945	3.11
1946	2.92
1947	2.83
1948	4.67
1949	3.74
1950	0.991
1951	1.33
1952	3.17
1953	3.91
1954	0.708
1955	1.70
1956	1.39
1957	5.10
1958	6.00
1959	1.90
1960	1.70
1962	3.03
1964	2.63
1965	3.68
1966	3.60
1967	2.07
1968	4.56
1969	1.44
1970	3.54
1971	2.38
1972	0.991
1973	7.36
1974	2.27
1975	6.54
1976	2.66
1977	2.15
1978	1.64
1979	3.57
1980	4.11
1981	1.87
1982	1.61
1999	3.45
2000	2.04
2001	5.97
2002	0.232
2003	1.59
2004	1.84
2005	2.46
2006	1.13
2007	1.70

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	1923–2007
Completeness	67.1% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	5 separate periods inside 1923–2007 hold no value. The longest runs from 1983 to 1998 — 16 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1923 and is not continuous from it: 85 years separate the first value from the last, and 67% 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 KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1924–2006.

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	KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO (mm)
1924	187
1925	74.0
1937	77.0
1938	128
1939	88.0
1940	46.0
1941	193
1942	172
1943	76.0
1944	113
1945	77.0
1946	53.0
1947	97.0
1948	123
1949	140
1950	37.0
1951	42.0
1952	111
1953	102
1954	42.0
1955	51.0
1956	47.0
1957	197
1958	165
1959	74.0
1960	78.0
1961	60.0
1962	102
1963	45.0
1964	73.0
1965	142
1966	61.0
1967	40.0
1968	98.0
1969	72.0
1970	110
1971	78.0
1972	54.0
1973	161
1974	72.0
1975	153
1976	78.0
1977	45.0
1978	72.0
1979	129
1980	129
1981	33.0
1999	106
2000	72.0
2001	113
2002	17.0
2003	54.0
2004	64.0
2005	72.0
2006	53.0

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	Derived Computed by Hydrionis
Period held	1924–2006
Completeness	66.3% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	2 separate periods inside 1924–2006 hold no value. The longest runs from 1982 to 1998 — 17 years with no reading. 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: 83 years separate the first value from the last, and 66% 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

The snow standing above this water

2 automated snow stations sit inside this drainage area, weighing the snowpack rather than measuring how deep it is.

265

Fullest snowpack recorded at Medano Pass, in 2008 (mm of water)

23

Thinnest, in 2018 (mm of water)

February

Month the pack is usually at its fullest

May

Month the pack has gone by, in half of years

Peak snowpack at Medano Pass

Water years 1996–2026. Each point is the fullest month of that snow season.

A water year runs October to September and is named for the year it ends, so the snow of one winter stays in one point. The value is the fullest month, not the fullest day: a pack that peaked sharply mid-month reads lower here than a single measurement taken at the right moment would.

View the data behind this chart

Underlying data
Period	Medano Pass (mm)
1996	106
1997	201
1998	193
1999	70.0
2000	115
2001	183
2002	101
2003	173
2004	144
2005	258
2006	46.0
2007	170
2008	265
2009	157
2010	166
2011	112
2012	177
2013	139
2014	108
2015	148
2016	139
2017	180
2018	23.0
2019	237
2020	168
2021	167
2022	168
2023	116
2024	110
2025	80.0
2026	69.0

Read against the river

Medano Pass and KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO both sit in this drainage area, and their records overlap by 10 years. That is the span the two have in common, not a count of years both actually hold — either record may have gaps inside it. The two are shown separately rather than on one axis: millimetres of stored water and cubic metres per second are not commensurable, and a difference between them would mean nothing.

Being in the same drainage area does not put the snowpack upstream of the gauge. A subbasin is an area, and snow on one tributary can join the river below a gauge on another — so a weak relationship here may say more about which tributary was measured than about the snow.

Every gauge Hydrionis holds within this area

Gauges within the San Luis and what each holds
Gauge	Measures	Values	Record
KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	204	1923–2026
SAN LUIS CREEK NEAR PONCHA PASS, CO.	catchment area, annual maximum river flow	8	1979–2026

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 — 13010003. 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
KERBER CR ABV LITTLE KERBER CR NR VILLA GROVE, CO	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
SAN LUIS CREEK NEAR PONCHA PASS, CO.	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	1	no
Years spanned	104	yes, 20 or more
Values held	812	no
Distinct measurements	6	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-08224500.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), San Luis gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-san-luis/

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 San Luis 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 confidence2007-05-16

Source: USGS — National Water Information System, USGS site 08224500, 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.