HR: 11:20h
AN: H11H-05    [PDF]
TI: Impacts of Climate Change on Regional Water Balance, With Application to the Illinois River Basin
AU: * Niemann, J D
EM: jniemann@engr.colostate.edu
AF: Colorado State University, Department of Civil Engineering, Fort Collins, CO 80523-1372
AU: Eltahir, E A
EM: eltahir@mit.edu
AF: Massachusetts Institute of Technology, Department of Civil and Environmental Engineering, Cambridge, MA 02139
AB: The objective of this analysis is to investigate the sensitivity of regional water balance components to changes in climate. To accomplish this objective, a simple model is developed to describe the partitioning of precipitation into surface runoff, groundwater runoff, and evapotranspiration. The fluxes are first described at the local-instantaneous scale and then integrated over the spatial and temporal distributions of precipitation and soil saturation to determine regional-climatological average fluxes and soil saturation. The model is applied first to the Illinois River Basin, where numerous observations are available to constrain the model components. The spatial distribution of soil saturation is found to conform to an Erlang distribution, while the temporal distribution of the spatially-averaged soil saturation conforms to a Beta distribution. Climate changes are assumed to come through changes in precipitation and potential evapotranspiration, and the sensitivity of the hydrologic components is assessed by calculating the partial derivatives of the components with respect to precipitation and potential evapotranspiration. We evaluate the sensitivity of the soil saturation as well as the main hydrologic fluxes (surface runoff, groundwater runoff, and evapotranspiration) for the current Illinois climate. We also investigate the sensitivity of hypothetical regions that differ from the Illinois base case in controlled ways. This procedure allows us to assess the roles played by various physical characteristics of the region. For Illinois, the soil saturation is observed to be more sensitive to changes in precipitation than the hydrologic fluxes. We also find that soil type is a key factor in determining the sensitivity of hydrologic fluxes to climate changes.
DE: 1699 General or miscellaneous
DE: 1836 Hydrologic budget (1655)
DE: 1866 Soil moisture
SC: Hydrology [H]
MN: 2003 Fall Meeting