Climate change impact on the hydrology of Spencer Creek watershed in Southern Ontario, Canada

This study is for the assessment of climate change impact on the future hydrology of Spencer Creek watershed located in Southern Ontario, Canada under the A2 scenario of the Special Report on Emissions Scenarios (SRES). The study is particularly concerned with changes in the climate variables and the seasonal and interannual flow regimes of the study area. The analysis also addresses the annual exceedance probability of extreme precipitation, temperature and flow events. Potential hydrologic effects of climate change were assessed for the Spencer Creek by imposing changes in precipitation and temperature derived from the North American Regional Climate Change Assessment Program (NARCCAP) climate simulations between 2040 and 2069. The climate models results were used as input to three hydrological models to produce projections of Spencer Creek watershed discharges. The results were compared to the observed discharges between 1989 and 2008. Notwithstanding the variability between the different regional climate model and hydrological model projections that envelop the future climate scenarios and the hydrological modeling uncertainties, all future simulations show an increase in the average interannual discharge, but also a noteworthy change in the seasonal distribution of the discharges. While the former is mainly attributed to the average annual precipitation, which tends to increase, the change in seasonal distribution of discharges is in line with the temperature increase of the winter and spring seasons that results in earlier snowmelt. Important changes were found in the annual exceedance probability (recurrence interval) of the extreme precipitation, temperature and runoff events.