This presentation will explore climate change and flow regulation impacts on daily and annual river discharge variations and trends into Hudson Bay, the Nechako and Fraser River Basins over the past half-century or so. The first part of the presentation will focus on the 3.7 million km2 Hudson Bay drainage basin for which daily observed streamflow data from the Water Survey of Canada, Manitoba Hydro, Ontario Power Generation and Hydro-Québec for 21 rivers were used to analyze the basin from 1960 to 2016. Decadal hydrographs were developed to assess the changing hydrological regimes in both regulated and unregulated sub-basins and spectral analyses are used to infer the dominant modes of temporal variability on the river discharge input to Hudson Bay. While the unregulated systems exhibit signals of climate change, these remain secondary relative to flow regulation even at the larger Hudson Bay drainage basin scale. More information and registration.