The monitoring network within this area

Hydrionis holds 1,045 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

1,045

Values held

1909–2026

Record spans

Gauges within the San Miguel 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 SAN MIGUEL RIVER NEAR PLACERVILLE, CO

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1909–2025.

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	SAN MIGUEL RIVER NEAR PLACERVILLE, CO (m³/s)
1909	283
1911	67.4
1930	48.4
1931	20.2
1932	36.0
1933	41.6
1934	18.6
1942	41.3
1943	25.5
1944	86.6
1945	40.5
1946	34.5
1947	37.7
1948	45.6
1949	67.1
1950	24.5
1951	20.8
1952	48.4
1953	49.8
1954	17.0
1955	32.3
1956	27.8
1957	66.5
1958	61.7
1959	31.7
1960	48.7
1961	38.2
1962	29.2
1963	25.9
1964	39.6
1965	68.0
1966	24.4
1967	27.3
1968	51.5
1969	30.0
1970	65.1
1971	38.8
1972	24.7
1973	75.3
1974	31.1
1975	56.9
1976	30.9
1977	14.6
1978	50.1
1979	62.0
1980	54.7
1981	32.6
1982	50.1
1983	108
1984	78.7
1985	55.2
1986	43.6
1987	50.7
1988	31.4
1989	22.3
1990	32.6
1991	29.2
1992	27.1
1993	45.9
1994	36.8
1995	59.7
1996	34.0
1997	50.7
1998	33.4
1999	62.0
2000	36.0
2001	52.7
2002	15.9
2003	47.6
2004	28.9
2005	45.9
2006	26.8
2008	51.5
2009	51.8
2010	54.1
2011	44.7
2012	16.8
2013	25.8
2014	46.4
2015	48.4
2016	46.4
2017	40.2
2018	12.8
2019	43.3
2020	26.0
2021	20.8
2022	23.6
2023	32.0
2024	40.8
2025	26.4

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	1909–2025
Completeness	76.9% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	4 separate periods inside 1909–2025 hold no value. The longest runs from 1912 to 1929 — 18 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1909 and is not continuous from it: 117 years separate the first value from the last, and 77% 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 SAN MIGUEL RIVER NEAR PLACERVILLE, 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. 1911–2024.

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	SAN MIGUEL RIVER NEAR PLACERVILLE, CO (mm)
1911	358
1931	155
1932	300
1933	219
1943	255
1944	360
1945	274
1946	228
1947	307
1948	343
1949	309
1950	184
1951	148
1952	340
1953	211
1954	165
1955	187
1956	176
1957	393
1958	401
1959	169
1960	254
1961	266
1962	260
1963	174
1964	211
1965	359
1966	195
1967	173
1968	246
1969	241
1970	291
1971	252
1972	175
1973	359
1974	185
1975	330
1976	177
1977	98.0
1978	264
1979	321
1980	274
1981	174
1982	330
1983	457
1984	462
1985	399
1986	349
1987	382
1988	206
1989	172
1990	166
1991	223
1992	247
1994	227
1995	414
1996	222
1997	412
1998	271
1999	370
2000	231
2001	244
2002	102
2003	202
2004	217
2005	283
2006	226
2007	291
2008	317
2009	257
2010	247
2011	275
2012	155
2013	180
2014	275
2015	285
2016	264
2017	271
2018	95.0
2019	331
2020	145
2021	148
2022	170
2023	282
2024	194

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	1911–2024
Completeness	74.6% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	3 separate periods inside 1911–2024 hold no value. The longest runs from 1912 to 1930 — 19 years with no reading. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1911 and is not continuous from it: 114 years separate the first value from the last, and 75% 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

1 automated snow station sits inside this drainage area, weighing the snowpack rather than measuring how deep it is.

713

Fullest snowpack recorded at Lone Cone, in 1997 (mm of water)

163

Thinnest, in 1990 (mm of water)

March

Month the pack is usually at its fullest

May

Month the pack has gone by, in half of years

Peak snowpack at Lone Cone

Water years 1981–2026. 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	Lone Cone (mm)
1981	262
1982	525
1983	486
1984	410
1985	494
1986	484
1987	486
1988	317
1989	476
1990	163
1991	425
1992	434
1993	613
1994	370
1995	586
1996	334
1997	713
1998	419
1999	306
2000	341
2001	353
2002	248
2003	350
2004	349
2005	443
2006	270
2007	351
2008	553
2009	417
2010	435
2011	339
2012	325
2013	326
2014	345
2015	278
2016	360
2017	513
2018	215
2019	537
2020	292
2021	305
2022	377
2023	591
2024	347
2025	265
2026	206

Read against the river

Lone Cone and SAN MIGUEL RIVER NEAR PLACERVILLE, CO both sit in this drainage area, and their records overlap by 44 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 Miguel and what each holds
Gauge	Measures	Values	Record
SAN MIGUEL RIVER NEAR PLACERVILLE, CO	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	299	1909–2026
SAN MIGUEL RIVER AT NATURITA, CO.	burned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year	192	1917–2026

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 — 14030003. 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
SAN MIGUEL RIVER NEAR PLACERVILLE, 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 MIGUEL RIVER AT NATURITA, 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 4 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	118	yes, 20 or more
Values held	1,045	yes, 1000 or more
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-09172500.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 Miguel gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-san-miguel/

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 Miguel 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 confidence2025-06-03

Source: USGS — National Water Information System, USGS site 09172500, 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.