The purpose of this project was to collect water samples from small rivers and estuaries throughout the Canadian Arctic Archipelago (CAA) to determine whether or not they significantly differed (on a purely geochemical basis) from larger North American rivers such as the Mackenzie and Yukon Rivers.  Water samples were collected from ten rivers (Coppermine, Ellice, Back, Hayes, Kuujuua, Karasok, Thomsen, Cunningham, Kangiqtugaapk, and Koogaaluk Rivers) during July and/or August of 2014, 2015, and 2016.  During both 2015 and 2016, water samples were also collected from the estuaries into which these rivers discharge.  These water samples were chemically analyzed to determine the influences of the river(s), sea ice melt, and seawater to each estuary.  Vertical profiles of temperature and salinity were collected within the estuaries to help determine the size and shape of the river plumes.  Together, these data help us to better understand the circulation and mixing within the estuaries.  Although the majority of the water samples were collected by research scientists during a 4-week period each summer, additional water samples were collected from the Coppermine and Kangiqtugaapk Rivers by local community members trained for this task.  Samples were collected on a weekly basis between June and October to determine how the chemistry of the rivers changed over time, and in response to the large decrease in the discharge that occurs between spring/early summer (peak discharge) and late fall (lowest or zero discharge). 

A postdoctoral research associate, K-12 science teacher, and graduate student all received training and experience collecting water samples from rivers and estuaries in high latitude environments as part of this project.  In addition, individuals living in Kugluktuk and Clyde River received training in the collection and storage of river water samples for chemical analyses.  Informal talks and radio interviews were also conducted at many of the communities visited in order to provide information about the project, address questions and concerns, and share preliminary scientific results.  A project website was constructed to further educate the public about the ongoing work and provide a platform for data access.  Annual reports were provided to local communities, agencies, and permitting and licensing organizations in three languages (English, Inuktitut, and Inuinnaqtun) to maximize the dissemination of project results.

We found that the combined discharge of rivers draining the CAA region is equal to that of the Mackenzie River, on the order of 300 km³ yr^-1.  We also found that CAA rivers vary considerably in their geochemical makeup due to differences in the rock and mineral content among drainage basins.  In general, CAA rivers differ from the Mackenzie and Yukon Rivers in terms of their geochemistry; it is important to consider these differences when studying the circulation and exchange of freshwater between the Arctic Ocean, the straits and channels of the CAA, and Baffin Bay.

The volume of water discharged by the rivers studied during this project varied considerably, from mean annual rates of 0.7 m³ s^-1 (Kangiqtugaapk River) to 494 m³ s^-1 (Back River).  There are three sources of relatively fresh water to Arctic estuaries:  river runoff, precipitation, and sea ice meltwater.  These freshwaters mix with saltier, ocean waters to produce the brackish waters of the estuary.  Despite the large range in runoff, rivers supplied > 50 % of the total freshwater in each estuary.  Furthermore, estimates of the time the river water spends in the estuary before being flushed out to sea (i.e., the residence time) indicated that river waters were generally present in the estuary for only a few days and the total time spent in the estuary was not dependent upon the rate of discharge. 

Last Modified: 10/25/2018
Modified by: Matthew B Alkire