Surface hydrology-climate interdependency in the Central Valley Agrosystem

In water controlled agrosystems such as California’s Central Valley, assessing the interdependence between climate and surface hydrology is needed to better understand the sustainability of water resources. The Central Valley also represents an important “field-laboratory” to assess large-scale aspects of the hydrological cycle and water resources. The present work aims to evaluate how agricultural activities affect surface hydrology during the summer and winter cycles of the 2001-2009 period. To model surface hydrological processes, we use the Variable Infiltration Capacity (VIC) model, forced with gridded precipitation, minimum and maximum temperatures using the index station method, provided by the University of Washington. Vegetation changes associated with agricultural activities in the Central Valley are estimated from MODIS LAI and ingested into VIC throughout 2001-2009, which is interesting because it includes both quite wet and very dry episodes. Soil moisture and evaporation observations at different points are used to assess the reliability VIC simulations. The interdependency between agriculture and surface hydrology with respect to climate is evaluated through the intraseasonal and interannual changes in agricultural activities and modeled hydrological measures, as represented by changes in the MODIS-LAI and the changes in soil moisture and evapotranspiration. Future work will include linkages to conjunctive use through the Central Valley Hydrologic Model with the MODFLOW Farm Process that simulates the interdependency between the surface water-groundwater interactions and climate.