Impacts of Changing Climatic Conditions in the Upper Thames River Basin

Abstract

This paper presents the application of the inverse approach in the study of high and low flows due to changing climatic conditions in the Upper Thames River basin, southwestern Ontario. The inverse approach is an alternative to statistical downscaling of global circulation model outputs, typically used in climate change studies. At the core of the inverse approach is a weather generator model that uses locally observed climate data, together with outputs from global circulation models, to generate an arbitrary long record of regional climatic conditions. A base case and two climate scenarios are produced by a weather generator, whose output is used as input into: (a) an event hydrologic model (for high flows); and (b) a continuous hydrologic model (for low flows). Changing hydrologic conditions are identified through frequency analysis for both flood and low flow hydrographs (obtained as outputs from hydrologic models). Changes in local water resources management practices, guidelines and design standards are recommended on the basis of the analysis of altered climates and their impacts on the hydrologic flow regime.