A flow-based ensemble strategy to assess the impact of climate change on watershed hydrology

Session: 35. - Watershed Modeling across all Scales from Small to Large

Feifei Dong, University of Toronto, [email protected]
Alex Neumann, University of Toronto Scarborough, [email protected]
Dong-Kyun Kim, University of Toronto Scarborough, [email protected]
Laud Matos, Environment and Climate Change Canada, [email protected]
George Arhonditsis, University of Toronto Scarborough, [email protected]

Abstract

Evaluation of hydrological response to future climate change is essential for risk assessment and adaptive management implementation in a watershed context. To assess climate change and its future impact on watershed hydrology, we developed a modelling framework integrating the Soil and Water Assessment Tool (SWAT) model with projections of General Circulation Models (GCMs). A season-specific, multi-site calibration strategy was used to characterize the hydrological processes in the Hamilton Harbour watershed. Temperature and precipitation projections of multiple GCMs were then used to force the calibrated SWAT model. We then evaluated several weighting schemes to combine the GCM projections and reproduce flow frequency distributions in six flow gauging stations. Our results suggest that a flow-based weighted ensemble outperformed the rest of methods examined. Our analysis projects that stream flow rates will likely increase in the winter and decrease during the growing season. Evapotranspiration across the watershed is also projected to increase due to warmer conditions. Our presentation will also attempt to shed light on the inteplay between urbanization and climate change and its potential implications on the basic features of extreme events (frequency, return period, intensity, and persistence).

1. Keyword
watersheds

2. Keyword
risk assessment

3. Keyword
climates

4. Additional Keyword
SWAT