HR: 0800h
AN: H41D-0446    [Abstracts]
TI: Effects of Land Use Change on Evapotranspiration and Water Yield in the Great Lakes Region
AU: * Mao, D
EM: maod@purdue.edu
AF: Department of Agricultural and Biological Engineering, Purdue University, 225 S. University St. 1146 ABE Buildiing, West Lafayette, IN 47907 United States
AU: Cherkauer, K A
EM: cherkaue@purdue.edu
AF: Department of Agricultural and Biological Engineering, Purdue University, 225 S. University St. 1146 ABE Buildiing, West Lafayette, IN 47907 United States
AB: Human activities have affected the exchange of energy and water between atmosphere and land surface through land use change. Conversion of large regions of pre-settlement forest and grassland to a majority cropland cover in the Great Lakes region has resulted in regional scale changes to hydrologic responses. Understanding the impact of historic land use change is important for management of future resources. Effects of land use change on the water and energy cycle of three Great Lakes states: Minnesota, Wisconsin, and Michigan, are analyzed using the Variable Infiltration Capacity (VIC) model. Land Data Assimilation System (LDAS) meteorological and soil data as well as pre-settlement and modern vegetation data taken from the USGS Land Use History of North American (LUHNA) were used as model input. Default vegetation input parameters were adjusted for the region based on a review of published studies. Results from a single grid cell vegetation sensitivity test show that on an average annual basis, forests transpire more than cropland and cropland more than grassland due to seasonal variations in Leaf Area Index (LAI) and stomatal resistances of vegetations. The hydrologic impact of region wide land use change was then analyzed by comparing simulations using both pre-settlement and current vegetation cover but the same meteorological forcings. Simulated changes resulting from land cover change vary with season and vegetation types. Reduction in forest cover increases water yield by decreasing evapotranspiration. Conversion between forest types resulted only in small differences in evaporation and water fluxes response. The most significant hydrologic changes were located in the southern part of the region where land use change has been primarily forest converted to cropland.
DE: 1655 Water cycles (1836)
DE: 1803 Anthropogenic effects (4802, 4902)
DE: 1836 Hydrological cycles and budgets (1218, 1655)
DE: 1842 Irrigation
SC: Hydrology [H]
MN: Fall Meeting 2005