The monitoring network within this area

Hydrionis holds 5,451 values from 23 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.

23
Gauges
5,451
Values held
1891–2026
Record spans
Gauges within the Santa Ana huc8 subbasin
23 monitoring points, positioned as the publisher records them.
Gauges within the Santa Ana huc8 subbasinSANTA ANA R NR MENTONE CA, MEEKS AND DALEY CN NR COLTON CA, LYTLE C NR FONTANA CA, LYTLE+BRLNE+COND+INF - W27 CA, CAJON C NR KEENBROOK CA, LONE PINE C NR KEENBROOK CA, DEVIL CYN C NR SAN BERNARDINO CA, TEMESCAL C NR CORONA CA, SAN ANTONIO C NR CLAREMONT CA, SANTA ANA R NR MENTONE CN + CN CA, MILL C NR YUCAIPA CA.+ CANALS CA, PLUNGE C NR EAST HIGHLANDS CA, CITY C WATER CO CN NR HIGHLAND CA, CITY C NR HIGHLAND CA, CITY C NR HIGHLAND CA.+ CANALS CA, E TWIN C NR ARROWHEAD SPRINGS CA, WATERMAN CANYON CREEK NR ARROWHEAD SPRINGS CA, SAN ANTONIO C NR CLAREMONT + CN CA, SANTIAGO C A SANTA ANA CA, SANTA ANA R A SANTA ANA CA, MILL C NR YUCAIPA CA, SAN TIMOTEO C NR REDLANDS CA, CUCAMONGA C NR UPLAND CASANTA ANA R NR MENTONE CAMEEKS AND DALEY CN NR COLTON CALYTLE C NR FONTANA CALYTLE+BRLNE+COND+INF - W27 CACAJON C NR KEENBROOK CALONE PINE C NR KEENBROOK CADEVIL CYN C NR SAN BERNARDINO CATEMESCAL C NR CORONA CASAN ANTONIO C NR CLAREMONT CASANTA ANA R NR MENTONE CN + CN CAMILL C NR YUCAIPA CA.+ CANALS CAPLUNGE C NR EAST HIGHLANDS CACITY C WATER CO CN NR HIGHLAND CACITY C NR HIGHLAND CACITY C NR HIGHLAND CA.+ CANALS CAE TWIN C NR ARROWHEAD SPRINGS CAWATERMAN CANYON CREEK NR ARROWHEAD SPRINGS CASAN ANTONIO C NR CLAREMONT + CN CASANTIAGO C A SANTA ANA CASANTA ANA R A SANTA ANA CAMILL C NR YUCAIPA CASAN TIMOTEO C NR REDLANDS CACUCAMONGA C NR UPLAND CA

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 SANTA ANA R NR MENTONE CA
The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1891–2025.
Shading marks when something was recorded, not what caused the line.
Largest measured flow of each year at SANTA ANA R NR MENTONE CALargest measured flow of each year at SANTA ANA R NR MENTONE CA: SANTA ANA R NR MENTONE CA in m³/s, from 1891 to 2025.Hurricane Katrina water and sanitation collapse05001,0001,5002,000m³/s18911928194319581973198820002014

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.

EventTypePeriodStandingAuthority
Hurricane Katrina water and sanitation collapseFlood2005-08-29 – 2005-09-30Documented 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
PeriodSANTA ANA R NR MENTONE CA (m³/s)
18911,521
1916824
19174.64
1918107
19194.11
192076.5
192131.1
192251.0
19245.49
19251.90
192652.4
1927680
192810.0
192914.7
19300
193142.5
19332.07
193522.1
193623.2
1937227
19381,481
193921.9
194039.4
19423.79
1943147
194425.2
194570.8
194641.1
19484.45
19493.06
19509.91
19511.08
19536.91
195458.0
195634.0
195748.4
195861.4
195918.5
19602.32
196224.0
196324.9
19642.61
196519.5
1966433
19688.16
1969433
197039.1
197155.8
197322.0
19745.89
197639.1
197714.3
197861.4
197947.6
1980168
19816.51
198265.1
198392.9
198433.7
198637.4
19884.19
19899.91
19904.02
199122.9
199229.4
1993199
199412.4
1995255
199638.2
199753.0
199885.2
19994.22
20006.97
20011.39
200317.3
20042.07
200583.8
200618.1
20079.49
200812.1
20091.84
201089.5
2011142
20132.94
20144.19
20154.84
20176.99
20182.63
201927.9
20209.94
20215.32
202325.1
202410.7
202516.0

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 existMeasured
Period held1891–2025
Completeness69.6% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps
  • 18 separate periods inside 1891–2025 hold no value. The longest runs from 1892 to 1915 — 24 years with no reading. They are drawn as breaks in the line and are never interpolated across.
ContinuityThe record begins in 1891 and is not continuous from it: 135 years separate the first value from the last, and 70% of the years between them are held. The span is not the record.
Last read from the publisher2026-10-01
RedistributionPermitted by the upstream licences
Commercial reusePermitted by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow 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 SANTA ANA R NR MENTONE CA, as a depth
The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1899–2024.
Shading marks when something was recorded, not what caused the line.
Water leaving the catchment above SANTA ANA R NR MENTONE CA, as a depthWater leaving the catchment above SANTA ANA R NR MENTONE CA, as a depth: SANTA ANA R NR MENTONE CA in mm, from 1899 to 2024.Hurricane Katrina water and sanitation collapse0200400mm18991918193419501966198219982014

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.

EventTypePeriodStandingAuthority
Hurricane Katrina water and sanitation collapseFlood2005-08-29 – 2005-09-30Documented 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
PeriodSANTA ANA R NR MENTONE CA (mm)
189936.0
190049.0
190192.0
190255.0
1903135
190550.0
1906155
1907258
190828.0
190991.0
1911115
191210.0
19136.00
191472.0
1915132
191722.0
191873.0
19196.00
192060.0
192151.0
1922213
192318.0
19245.00
19255.00
192636.0
1927117
19284.00
19298.00
193011.0
193110.0
193249.0
19337.00
19349.00
193512.0
193622.0
1937158
1938309
193915.0
194021.0
194172.0
19426.00
194356.0
194418.0
194546.0
194619.0
19479.00
19481.00
19495.00
19503.00
19517.00
195238.0
19532.00
195424.0
19553.00
19566.00
19576.00
195864.0
19592.00
19601.00
19611.00
196217.0
19632.00
19641.00
196555.0
196692.0
196786.0
19687.00
1969491
197058.0
197140.0
197211.0
197369.0
197414.0
19759.00
197615.0
19778.00
1978168
1979136
1980409
198112.0
198253.0
1983262
198416.0
19859.00
198626.0
19874.00
19884.00
19895.00
19901.00
199113.0
199223.0
1993291
199414.0
1995194
199635.0
199726.0
1998199
199927.0
200015.0
20013.00
20025.00
200319.0
200419.0
2005230
200659.0
200719.0
200843.0
200914.0
201052.0
2011164
201223.0
201316.0
201414.0
201513.0
20169.00
201733.0
201811.0
2019122
202066.0
202126.0
202228.0
2023236
2024118

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 existDerived Computed by Hydrionis
Period held1899–2024
Completeness97.6% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps
  • 3 separate periods inside 1899–2024 hold no value. They are drawn as breaks in the line and are never interpolated across.
ContinuityThe record begins in 1899 and is not continuous from it: 126 years separate the first value from the last, and 98% of the years between them are held. The span is not the record.
Inputs last read2026-10-01 · when the records this was computed from were last read from their publishers
Calculation date2026-08-24 · when the calculation method was last versioned, not a reading of any publisher
RedistributionPermitted by the upstream licences
Commercial reusePermitted by the upstream licences. No Hydrionis access tier can widen this.
MethodologyHow this was produced

Every gauge Hydrionis holds within this area

Gauges within the Santa Ana and what each holds
GaugeMeasuresValuesRecord
SANTA ANA R NR MENTONE CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3921891–2026
PLUNGE C NR EAST HIGHLANDS CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3561919–2026
CITY C NR HIGHLAND CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3541919–2026
DEVIL CYN C NR SAN BERNARDINO CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3501920–2026
E TWIN C NR ARROWHEAD SPRINGS CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3481920–2026
LYTLE C NR FONTANA CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3361918–2026
SANTA ANA R A SANTA ANA CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year3071923–2026
LYTLE+BRLNE+COND+INF - W27 CAburned area within 50 km, annual maximum river flow, mean river flow, mean river flow, water year3061904–2025
SANTA ANA R NR MENTONE CN + CN CAburned area within 50 km, annual maximum river flow, mean river flow, mean river flow, water year2861912–2025
WATERMAN CANYON CREEK NR ARROWHEAD SPRINGS CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2841912–2026
CITY C NR HIGHLAND CA.+ CANALS CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2711924–2026
LONE PINE C NR KEENBROOK CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2661920–2026
SANTIAGO C A SANTA ANA CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2521930–2026
CAJON C NR KEENBROOK CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2041920–2026
SAN ANTONIO C NR CLAREMONT CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year2011917–2026
TEMESCAL C NR CORONA CAburned area within 50 km, catchment area, annual maximum river flow, mean river flow, mean river flow, water year1841928–2026
CITY C WATER CO CN NR HIGHLAND CAburned area within 50 km, mean river flow, mean river flow, water year1561927–2024
MILL C NR YUCAIPA CA.+ CANALS CAburned area within 50 km, mean river flow, mean river flow, water year1481919–2019
MEEKS AND DALEY CN NR COLTON CAburned area within 50 km, mean river flow, mean river flow, water year1471920–2019
SAN ANTONIO C NR CLAREMONT + CN CAburned area within 50 km, mean river flow, mean river flow, water year1461916–2019
MILL C NR YUCAIPA CAcatchment area, annual maximum river flow561920–2026
SAN TIMOTEO C NR REDLANDS CAcatchment area, annual maximum river flow521927–2026
CUCAMONGA C NR UPLAND CAcatchment area, annual maximum river flow491928–2026

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 — 18070203. 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
GaugeEvidenceEstablished
SANTA ANA R NR MENTONE CAStated 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/42026-10-02
PLUNGE C NR EAST HIGHLANDS CAStated 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/42026-10-02
CITY C NR HIGHLAND CAStated 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/42026-10-02
DEVIL CYN C NR SAN BERNARDINO CAStated 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/42026-10-02
E TWIN C NR ARROWHEAD SPRINGS CAStated 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/42026-10-02
LYTLE C NR FONTANA CAStated 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/42026-10-02
SANTA ANA R A SANTA ANA CAStated 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/42026-10-02
LYTLE+BRLNE+COND+INF - W27 CAStated 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/42026-10-02
SANTA ANA R NR MENTONE CN + CN CAStated 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/42026-10-02
WATERMAN CANYON CREEK NR ARROWHEAD SPRINGS CAStated 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/42026-10-02
CITY C NR HIGHLAND CA.+ CANALS CAStated 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/42026-10-02
LONE PINE C NR KEENBROOK CAStated 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/42026-10-02
SANTIAGO C A SANTA ANA CAStated 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/42026-10-02
CAJON C NR KEENBROOK CAStated 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/42026-10-02
SAN ANTONIO C NR CLAREMONT CAStated 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/42026-10-02
TEMESCAL C NR CORONA CAStated 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/42026-10-02
CITY C WATER CO CN NR HIGHLAND CAStated 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/42026-10-02
MILL C NR YUCAIPA CA.+ CANALS CAStated 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/42026-10-02
MEEKS AND DALEY CN NR COLTON CAStated 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/42026-10-02
SAN ANTONIO C NR CLAREMONT + CN CAStated 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/42026-10-02
MILL C NR YUCAIPA CAStated 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/42026-10-02
SAN TIMOTEO C NR REDLANDS CAStated 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/42026-10-02
CUCAMONGA C NR UPLAND CAStated 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/42026-10-02

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 5 of them, which makes it a full profile.

Information-gain signals held for this water body
SignalHeldCounts
Gauges holding a real record22yes, 3 or more
Years spanned136yes, 20 or more
Values held5,451yes, 1000 or more
Distinct measurements5yes, 2 or more
Publishers measuring it2yes, 2 or more
Official identifiers1recorded, not counted

Use this data

Use this data

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), Santa Ana gauge records, accessed 2026-10-05, hydrionis.com/waters/united-states-santa-ana/

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 Santa Ana 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 11051500, 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.