Uncertainty in future streamflow for the Nelson-Churchill River, Manitoba, Canada

The impact of two types of reanalysis data (Watch Forcing Data (WFD) and HydroGFD2.0) on long-term water supply projection will be compared for the Nelson-Churchill River basins in Canada. This information is critical to Global Water Futures (GWF), who use reanalysis data in models to produce contemporary and long-term water supply information.


Issue to be addressed

The Nelson-Churchill River basin in Canada covers the Canadian Boreal and Prairie ecozones, has a highly seasonal (snowmelt and rainfall) regime, with low-relief and significant redistribution of snow, includes discontinuous permafrost, and is a major freshwater discharge to the Hudson Bay and Canadian pan-Arctic. This basin is susceptible to climate change impacts, which have already resulted in a changing hydrologic and climatic regime, with 3 of the top 5 worst Canadian floods in history occurring in recent decades within the basin (i.e., Manitoba). It is a relatively data-sparse region of hydrological, ecological and economic importance. As a result, long-term planning of water resources within the basin relies on hydrologic simulation, specifically, long-term simulation under future climates. In this region, there is considerable uncertainty in both historic climatology and future projections, which inherently impact long-term streamflow projections. We compare the changes in streamflow simulation and projection resulting from two reanalysis products: WFD and HydroGFD2.0.

Decision support to client

The HYPE model is of interest for use by various Canadian stakeholders through the Global Water Futures funded IMPC (Integrated Modelling Project of Canada’s largest River Basins) project, including Environment and Climate Change Canada and Manitoba Hydro, hydropower utility with generation capacity in the Nelson River basin. Manitoba Hydro is interested in using models, such as HYPE, for long-term planning of generation capacity under future climates. They are also an identified stakeholder in the IMPC project.

Temporal and spatial scale

Simulations will be derived for, and assessed over three specific periods: historic (1981-2010), near future (2021-2040), and far future (2041-2070). For stakeholder long-term planning (Manitoba Hydro), a combined future period will also be assessed from 2021-2070 given decision-making time horizons are on the order of 50-100 years. Though the historic reference period is from 1981-2010, simulations will be run from 1961-2015 for model calibration and validation. 

The spatial domain is the Nelson-Churchill River basin (~1.2 million km2), a regional-scale of National importance due to its influence on the freshwater regime of Hudson Bay. It is the primary water supply for Manitoba Hydro and one of the key basins of interest for the GWF-IMPC project. 

Knowledge brokering

The purveyor is part of the GWF-IMPC project and in direct contact with GWF and stakeholders interested in IMPC project outcomes, including Manitoba Hydro. As part of their mandate, GWF has mechanisms in place for technology transfer and stakeholder engagement. Knowledge is communicated through workshops, WebEx seminars, newsletters, technical documents and exchange of expertise (technical training seminars).