Woodwell Climate Research Center
info@arcticgreatrivers.org

Since 2003

ArcticGRO tracks the water and chemistry that the largest Arctic rivers carry to the Arctic Ocean.

Consistent water sampling on the six largest Arctic rivers, and daily discharge for 15 rivers. All data are free to use by anyone, for any purpose.

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Yukon River near Pilot Station. August 2015. Photo by John Schade.

15
rivers with daily discharge
6
largest Arctic rivers sampled for chemistry
1927
first year of discharge data (Kolyma)
2003
consistent chemistry sampling since
341
publications using ArcticGRO data

The six rivers ArcticGRO samples drain two-thirds of the Arctic Ocean watershed, so their chemistry tracks change across permafrost landscapes in Russia, Canada and Alaska. (Tank et al. 2023, Nature Geoscience)

Why Arctic rivers matter

Changes in river flow and chemistry reflect what is happening across vast, rapidly warming watersheds, and shape the coastal ocean that receives them. More about ArcticGRO

Satellite image of the Kolyma River delta, where the river's channels spread out and its sediment-laden water flows into the East Siberian Sea.
Image: Greg Fiske

Freshwater

Rivers deliver freshwater that shapes Arctic Ocean salinity, sea ice and circulation.

Three ArcticGRO team members collecting river water samples from a boat on the Yukon River at Pilot Station, Alaska.
Sampling at Pilot Station. Photo by Mia DiLorenzo

Carbon and nutrients

Rivers carry carbon from thawing permafrost, and nutrients, to coastal seas.

Max Holmes collecting a river water sample on the Lena River at Zhigansk.
Max Holmes sampling in Zhigansk

A climate signal

Long-term records show discharge from large Eurasian Arctic rivers increasing (Peterson et al. 2002).

Latest year

2025 on the Ob': spring flood peaked at 38,600 m³/s on 17–18 June

Explore all 17 stations →
Daily discharge of the Ob' River at Salekhard in 2025 compared with the 1991–2020 range and median; the spring flood peaked at 38,600 cubic metres per second on 17–18 June, above the median peak.

Daily discharge, m³/s. Data updated 10 December 2025 · Roshydromet / AARI provisional data.

Map of the Arctic showing the river basins monitored by ArcticGRO: Yukon, Mackenzie, Kolyma, Indigirka, Yana, Lena, Olenek, Yenisey, Ob', Pur, Nadym, Pechora, Mezen, Northern Dvina and Onega.

Where we work

Water chemistry is sampled near the mouths of the six largest Arctic rivers. Daily discharge comes from 17 gauges on 15 rivers, operated by Roshydromet, the U.S. Geological Survey and the Water Survey of Canada.

Meet the rivers Open the discharge explorer

More than twenty years of sampling, through every season

Daily discharge Water sample Project phases: PARTNERS, ArcticGRO I–V
Daily discharge of the Yukon, Mackenzie, Ob', Yenisey, Lena and Kolyma since 2003, with every ArcticGRO water sample marked on the hydrograph. Samples are spread across spring floods, summer and winter low flow in every year; sampling on the four Russian rivers ends in 2023.

Tap or click the chart to open it full size. Explore discharge and chemistry for each river.

Data updates

Water quality New portal for chemistry data Browse and download the latest water quality data. Discharge Discharge dataset on Zenodo Version v20261104, with a DOI to cite: 10.5281/zenodo.23957360 Publications Searchable list of 341 papers Filter by year and type, find free-to-read versions.