The monitoring network within this area

Hydrionis holds 427 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

427

Values held

1869–2026

Record spans

Gauges within the Middle Guadalupe 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 Comal Rv at New Braunfels, TX

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1869–2025.

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	Comal Rv at New Braunfels, TX (m³/s)
1869	0
1870	0
1872	0
1913	0
1928	140
1929	0
1930	166
1931	0
1932	0
1933	28.9
1934	33.1
1935	0
1936	0
1937	149
1938	119
1939	12.1
1940	62.0
1941	0
1942	0
1945	117
1946	190
1948	0
1949	63.7
1951	23.0
1952	991
1953	96.8
1955	16.7
1956	34.0
1957	244
1958	71.4
1959	34.0
1960	69.7
1961	63.7
1962	24.3
1964	36.8
1965	195
1967	58.6
1968	168
1969	25.4
1970	104
1972	1,722
1973	227
1974	53.8
1975	270
1976	161
1977	108
1978	126
1980	27.8
1981	108
1982	143
1983	22.1
1984	16.4
1985	109
1986	127
1987	16.0
1989	26.2
1990	19.5
1991	45.6
1993	188
1994	152
1996	17.1
1997	53.2
1998	23.1
2000	28.9
2001	49.0
2002	580
2004	419
2006	84.1
2007	151
2008	20.9
2009	30.3
2010	886
2011	12.4
2012	28.9
2013	17.6
2015	83.5
2018	36.5
2019	39.4
2020	32.6
2021	41.9
2023	18.5
2024	24.0
2025	189

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	1869–2025
Completeness	52.9% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	20 separate periods inside 1869–2025 hold no value. The longest runs from 1873 to 1912 — 40 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1869 and is not continuous from it: 157 years separate the first value from the last, and 53% 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 Comal Rv at New Braunfels, TX, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1933–2025.

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	Comal Rv at New Braunfels, TX (mm)
1933	826
1934	843
1935	896
1936	972
1937	949
1938	936
1939	798
1940	764
1941	955
1942	972
1943	904
1944	928
1945	992
1946	1,012
1947	945
1948	737
1949	777
1950	695
1951	545
1952	595
1953	523
1954	360
1955	245
1956	103
1957	508
1958	857
1959	840
1960	885
1961	908
1962	708
1963	552
1964	508
1965	766
1966	709
1967	500
1968	904
1969	778
1970	830
1971	585
1972	969
1973	1,077
1974	1,040
1975	1,082
1976	1,026
1977	1,061
1978	879
1979	1,073
1980	759
1981	859
1982	737
1983	630
1984	335
1985	705
1986	805
1987	995
1988	736
1989	433
1990	475
1991	681
1992	1,232
1993	1,057
1994	851
1995	739
1996	464
1997	708
1998	1,106
1999	912
2000	713
2001	947
2002	1,244
2003	1,044
2004	1,165
2005	1,064
2006	725
2007	1,015
2008	862
2009	693
2010	1,003
2011	605
2012	590
2013	478
2014	345
2015	724
2016	1,001
2017	929
2018	770
2019	923
2020	753
2021	746
2022	462
2023	319
2024	316
2025	258

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	1933–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1933 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 Middle Guadalupe and what each holds
Gauge	Measures	Values	Record
Comal Rv at New Braunfels, TX	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	230	1869–2026
Guadalupe Rv abv Comal Rv at New Braunfels, TX	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	197	1928–2026

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 — 12100202. 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
Comal Rv at New Braunfels, TX	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
Guadalupe Rv abv Comal Rv at New Braunfels, TX	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	158	yes, 20 or more
Values held	427	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-08169000.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), Middle Guadalupe gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-middle-guadalupe/

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 Middle Guadalupe 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 confidence2025-06-12

Source: USGS — National Water Information System, USGS site 08169000, 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.