Surface water hydrology in integrated watershed models: Patuxent case study.

Voinov, A., R. Costanza

ABSTRACT
The Patuxent Landscape Model (PLM) is designed to simulate fundamental ecological processes in interaction with an economic component that determines the land use patterns. The PLM is based on a modified General Ecosystem Model (GEM) that is replicated in each of the cells that compose the rasterized landscape. Hydrologic flows are crucial to link the cells together horizontally. Modeling surface water flows in the watershed scale implies certain restrictions on the spatial, temporal and structural resolution of the methods involved and processes considered. The spatial resolution in such models is coarse and the time step tends to be large enough to make space for simulation of other ecological and economic processes of interest. The quasi-empirical hydrologic module of the PLM was built in attempt to compromise between the heterogeneity of spatial hydrologic fluxing and the spatial and structural complexity of other model components. Rescaling experiments are performed to define the spatial sensitivity to various processes and land use changes. The calibration process and some scenario runs are discussed.