The effects of contemporary increases in riverine freshwater into the Arctic Ocean are estimated from ocean model simulations, using two runoff data sets. One runoff data set which is based on older climatological data, which has no inter-annual variability after 2007 and as such does not represent the observed increases in river runoff into the Arctic. The other data set comes from a hydrological model developed for the Arctic drainage basin, which includes contemporary changes in the climate. In the pan-Arctic this new data set represents an approximately 11% increase in runoff, compared with the older climatological data. Comparing two ocean model runs forced with the different runoff data sets, overall changes in different freshwater markers across the basin were found to be between 5-10%, depending on the area investigated. The strongest increases were seen from the Siberian rivers, which in turn caused the strongest freshening in the Eastern Arctic.

Issues surrounding gender equality are – and should be - front and centre in the water resources community, and other STEM fields. Very necessarily, the focus tends to remain on recruitment and inclusivity offering support for students and early career academics. The leaky pipeline concept used to describe the incremental loss of women from STEM fields with career duration results in a disproportionate loss of women, creating a parallel problem where highly qualified, top tier academics are disproportionately lost from the system after significant financial and personnel investment by institutions is made. Ultimately, the leaky pipeline undermines the extensive investment of the hydrology and other STEM communities in equity, diversity, inclusion, and accessibility (EDIA) recruitment and retention programs by cutting short career ambitions and the trajectories of diverse top performing individuals, resulting in no net benefit of EDIA policy investments. Addressing this critical gender gap requires the attention and support of the hydrology community of practice with specific focus on generating opportunities for advancement, confronting systemic and structural biases, and improving education around allyship. Institutions and professional organizations need to consciously grow diversity in leadership and recognize and outwardly manage the perception of academic excellence around slow research and education that attracts increased diversity. Supporting allyship, reducing competitiveness among community members, and reinforcing collaboration will not only attract, but retain, a higher proportion of diversity in the hydrology community, academia, and STEM professions in general. It is time for the water resources (and other STEM) communities to demand broader accountability and recognition of the barriers to women, implement and reward more diverse definitions of research excellence, and offer allyship training to the community of practice at large.

Lakes and reservoirs are an important part of the terrestrial water cycle. However, relatively little attention has been given to lake and reservoir water balance modelling, their impacts, and interaction with complex terrestrial system processes. In this work, we present the implementation of lakes and reservoirs into mizuRoute, a vector-based routing model (termed mizuRoute-Lakes) that is agnostic to the choice of hydrologic or land model. In this work, we demonstrate capabilities of mizuRoute-Lake in modeling the water balance of lakes and reservoirs namely (1) data-driven lake/reservoir models; (2) multi-model lake models; and (3) abstraction from lakes, reservoirs, and river segments. Applications presented in this work are at global, regional, and local scales. The data-driven and parametric capabilities that are provided in mizuRoute enable incorporating past or future altimetry data (e.g. from the Surface Water and Ocean Topography, SWOT, mission for estimation of lakes and reservoirs storage) or information from water management model simulations regarding water demand and reservoir operation under climate change scenarios. We believe the capabilities presented in mizuRoute-Lake will enable the modellers to diagnose and compare water balance models in a more rigorous manner.

This study investigates the impacts of climate change on the hydrology and soil thermal regime of ten sub-arctic watersheds (northern Manitoba, Canada) using the Variable Infiltration Capacity (VIC) model. We utilize statistically downscaled and bias-corrected forcing datasets based on 17 general circulation model (GCM) - representative concentration pathways (RCP) scenarios from phase 5 of the Coupled Model Intercomparison Project (CMIP5) to run the VIC model for three 30-year periods: a historical baseline (1981–2010), and future projections (2021–2050: 2030s and 2041–2070: 2050s), under representative concentration pathways (RCPs) 4.5 and 8.5. The CMIP5 Multi-Model Ensemble (MME) mean-based VIC simulations indicate a 15–20% increase and 10% decrease in the projected annual precipitation and snowfall, respectively over the southern portion of the basin and >20% rainfall increase over the higher latitudes of the domain by the 2050s. Snow accumulation is projected to decline across all sub-basins, particularly in the lower latitudes. Projected uncertainties in major water balance components (i.e., evapotranspiration, surface runoff, and streamflow) are more substantial in the wetland and lake-dominated Grass and Gunisao watersheds than their eight counterparts. Future warming increases soil temperatures >2.5°C by the 2050s, resulting in 40–50% more baseflow. Further analyses of soil temperature trends at three different depths show the most pronounced warming in the top soil layer (1.6°C 30-year-1 in the 2050s), whereas baseflow increases substantially by 19.7% and 46.3% during the 2030s and 2050s, respectively. These results provide crucial information on the potential future impacts of warming soil temperatures on the hydrology of sub-arctic watersheds in north-central Canada and similar hydro-climatic regimes.

A document by Tricia A. Stadnyk. Click on the document to view its contents.