Modeling the Impacts of Climate Change on Water Supply Reliabilities
Ranjan S. Muttiah, Ralph A. Wurbs
International Water Resources Association Water International, Volume 27, Number 3, September 2002
Ranjan S. Muttiah, Texas Agricultural Experiment Station, Texas A&M University, Temple, Texas, USA, and Ralph A. Wurbs, Member IWRA, Texas A&M University, College Station, Texas, USA
A strategy is presented for predicting impacts of future climate change on water supply capabilities, which is based on using output from a general circulation model (GCM) developed by the Canadian Center for Climate Modeling and Analysis (CCCma) with a watershed hydrology model and a river/reservoir system management model. The GCM output was used to adjust input to a watershed hydrology model in order to predict the corresponding impacts on streamflows. Output from the watershed model was used to adjust naturalized streamflows in a river/reservoir system management model in order to determine the corresponding impacts on water supply reliabilities.
The methodology was applied in an investigation of capabilities for supplying water to the City of Houston and other users in the San Jacinto River Basin of Texas. Historical versus 2040 to 2059 climate scenarios were compared. Study results indicate that long-term mean streamflows under 2040 to 2059 climate conditions were higher than under historical climate due to significant increases in floods and other high flows. However, flows were lower for the future climate scenario during periods of normal and low flows. Seasonal variations in flows were greater with the future climate scenario than the historical climate. Reservoir storage fluctuations increase under future climate. Due to relatively large storage capacities, reliabilities for water supply diversions were improved somewhat under future climate conditions.
This research stems in part from studies associated with the Water Rights Analysis Program (WRAP), which TWRI has helped support over several years.
Go to the International Water Resources Association to obtain the paper.