High Resolution Modelling of Climate Change Impacts on Water Supply and Demand, Crop Nutrient Usage and GHG emissions, Similkameen Watershed, British Columbia, Canada

Abstract:

The Similkameen watershed in southern British Columbia, Canada is expected to warm substantially in the coming decades. A higher proportion of winter rain to snow and an earlier onset of spring snowmelt are likely to result in lower spring stream flow peaks. The reduction in winter water storage, combined with longer, warmer, and drier summers, poses a challenge for water resources in an irrigation-based agricultural watershed. There are already substantial irrigation developments, and water demands are expected to increase to maintain current agricultural production, further stressing a shrinking summer water supply.

Agriculture releases significant amounts of CO2, CH4 and N2O to the atmosphere, accounting for approximately 8% of anthropogenic greenhouse gas (GHG) emissions in Canada, excluding CO2 emissions from fuels. Agricultural GHG fluxes are complex but the active management of agricultural systems offers possibilities for mitigating GHG emissions. Although GHG emissions derived from soil have been researched for several decades, there are still geographic regions and agricultural systems that have not been well characterized.

This work will address a series of questions for the Similkameen watershed. For a range of climate scenarios, we will: (i) use the GENESYS (GENerate Earth SYstems Science input) hydrometeorological model to simulate historical and future water supplies; (ii) link GENESYS and AquaCrop models to assess climate driven changes in water requirement and associated crop productivity; and (iii) link GENESYS and HOLOS (whole-farm model and software program that estimates GHG emissions) to estimate farm and regional level GHG emissions and seasonal nutrient balance for the crops in the watershed.