The monitoring network within this area

Hydrionis holds 379 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

379

Values held

1917–2026

Record spans

Gauges within the Headwaters Connecticut River 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 CONNECTICUT RIVER NEAR DALTON, NH

The highest instantaneous discharge the publisher recorded in each year — a flood peak as measured, not a daily average of one. 1928–2025.

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	CONNECTICUT RIVER NEAR DALTON, NH (m³/s)
1928	1,254
1929	799
1930	484
1931	450
1932	572
1933	1,014
1934	892
1935	637
1936	1,368
1937	555
1938	555
1939	668
1940	886
1941	547
1942	654
1943	606
1944	578
1945	705
1947	617
1948	476
1949	453
1950	603
1952	518
1953	980
1954	966
1955	767
1956	510
1957	391
1958	810
1959	416
1960	776
1961	518
1962	586
1963	597
1964	691
1965	243
1966	413
1967	436
1968	433
1969	833
1970	680
1971	487
1972	912
1973	589
1974	753
1975	459
1976	640
1977	532
1978	532
1979	558
1980	323
1981	586
1982	708
1983	496
1984	804
1985	343
1986	719
1987	827
1988	481
1989	790
1990	1,096
1991	612
1992	753
1993	490
1994	779
1995	847
1996	861
1997	428
1998	1,189
1999	462
2000	682
2001	915
2002	917
2003	564
2005	513
2007	617
2008	555
2009	422
2010	467
2011	940
2012	442
2013	600
2014	1,002
2015	510
2016	377
2017	589
2018	651
2019	1,056
2020	493
2021	498
2022	379
2023	481
2024	600
2025	677

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	1928–2025
Completeness	95.9% of the periods in that span are held. Gaps are drawn as breaks and never interpolated.
Known gaps	4 separate periods inside 1928–2025 hold no value. They are drawn as breaks in the line and are never interpolated across.
Continuity	The record begins in 1928 and is not continuous from it: 98 years separate the first value from the last, and 96% 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 CONNECTICUT RIVER NEAR DALTON, NH, as a depth

The year's flow spread over the land draining to this gauge, in millimetres — the same unit rainfall is measured in. 1928–2025.

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	CONNECTICUT RIVER NEAR DALTON, NH (mm)
1928	794
1929	705
1930	633
1931	533
1932	716
1933	673
1934	697
1935	608
1936	834
1937	751
1938	701
1939	650
1940	579
1941	455
1942	592
1943	766
1944	601
1945	803
1946	644
1947	742
1948	543
1949	521
1950	648
1951	607
1952	585
1953	592
1954	977
1955	623
1956	609
1957	597
1958	702
1959	693
1960	597
1961	543
1962	662
1963	619
1964	542
1965	505
1966	563
1967	567
1968	596
1969	841
1970	651
1971	574
1972	673
1973	917
1974	807
1975	607
1976	839
1977	773
1978	622
1979	649
1980	525
1981	710
1982	668
1983	728
1984	660
1985	560
1986	637
1987	536
1988	595
1989	637
1990	857
1991	681
1992	540
1993	603
1994	628
1995	545
1996	915
1997	672
1998	746
1999	641
2000	744
2001	524
2002	715
2003	673
2004	647
2005	902
2006	879
2007	759
2008	938
2009	786
2010	766
2011	854
2012	598
2013	690
2014	724
2015	684
2016	582
2017	749
2018	707
2019	864
2020	627
2021	458
2022	615
2023	804
2024	777
2025	598

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	1928–2025
Completeness	100.0% of the periods in that span are held.
Continuity	Continuous: every year from 1928 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 Headwaters Connecticut River and what each holds
Gauge	Measures	Values	Record
CONNECTICUT RIVER NEAR DALTON, NH	burned area within 50 km, catchment area, annual maximum river flow, mean river flow	233	1928–2026
CONNECTICUT R AT FIRST CONN LK NR PITTSBURG, NH	catchment area, annual maximum river flow, mean river flow	146	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 — 01080101. 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
CONNECTICUT RIVER NEAR DALTON, NH	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
CONNECTICUT R AT FIRST CONN LK NR PITTSBURG, NH	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	110	yes, 20 or more
Values held	379	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-01131500.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), Headwaters Connecticut River gauge records, accessed 2026-09-02, hydrionis.com/waters/united-states-headwaters-connecticut-river/

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 Headwaters Connecticut River 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 confidence2025-03-19

Source: USGS — National Water Information System, USGS site 01131500, 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.