This data set describes the stable water isotope (δ18O-H2O, δ2H-H2O), Dissolved Organic Carbon (DOC), and Nutrient (Nitrate + Nitrite, Phosphate, Silicate) data collected from 53 rivers, lakes, and glaciers throughout the Canadian Arctic Archipelago (CAA) and Hudson Bay as part of the Canadian Arctic Archipelago Rivers Program (CAA-RP; 2016 – 2019); ArcticNet / Amundsen Science biogeochemical surveys (2017-2019); the Canada 150 C3 Expedition (2017); and the BaySys project (2018). Water samples were collected according to methods developed by the Arctic Great Rivers Observatory (http://www.arcticgreatrivers.org/), described in detail in Brown et al., 2020. Water collected for stable water isotope, DOC, and Nutrient analyses was filtered through 0.22 μm Sterivex cartridges (Millipore) into triply rinsed glass (isotopes) or HDPE (Nutrients, DOC) vials; HDPE vials were acid cleaned prior to use. Samples for the determination of DOC and Nutrients were frozen until analyses, whereas stable isotope samples were stored in the dark at room temperature or refrigerated until analyses. Analytical methods are described in the accompanying metadata file. Where indicated, water Temperature and Conductivity at the time of sampling were determined as described in the dataset metadata file.

Acknowledgments:This sampling program would not be possible without the help of many enthusiastic and supportive partners who have carried sampling kits with them across the CAA! Many thanks go to the Captain and Crew of the CCGS Amundsen, the Captain and Crew of the RV Martin Bergmann, the Captain Crew of the MV Polar Prince, and the staff at the Canadian High Arctic Research Station, as well as Austin Maniyogina, Amanda Dumond, Patrick Duke, Shawn Marriott, Francis Emingak, Araleigh Cranch, Richard Sims, Peter Van Buren, Geraint Element, Kathleen Munson, Mohamed Ahmed, Kate Yezhova, ArcticNet, Amundsen Science, Adrian Schimnowski, Tara Mascarenhas, Mark Graham, Eddy Carmack, Mike Dempsey, and Baba Pedersen for sample collection and logistical assistance, as well as Sarah-Ann Quesnel, Cynthia Wright, Owen Cowling, Joseph Orchardo, Gretchen Swarr, Jean-Eric Tremblay, Jonathan Gagnon, Gabriele Deslongchamps, Helmuth Thomas, Monica Nelson, Tonya Burgers, Jacoba Mol, and Araleigh Cranch for assistance with laboratory analyses. The Canadian Arctic Archipelago Rivers Program was supported by the Department of Fisheries and Oceans Canada, the Woods Hole Oceanographic Institution Coastal Ocean Institute, the Arctic Research Foundation, and Polar Knowledge Canada.