To evaluate the hydrologic and biogeochemical response of freshwater watersheds to climatic variability properly, a mathematical model with detailed parameterization in describing the hydrologic and thermal processes in a watershed is needed. For this purpose, the Enhanced Trickle Down model was modified to predict the hydrologic and thermal responses of freshwater watersheds to various climate change scenarios. Modifications of the model included the incorporation of an energy transfer submodel, an improved hydraulic conductivity scheme, and the coupling with a point source snowmelt model. The results of calibration and verification of the model using 8 years of field data collected at the Agricultural Research Service, W-3 watershed, located near Danville, Vermont, are presented. Forecast System. Their results indicated a seasonal shift in the snow accumulation pattern, increased winter runoff, and increased flood maxima under atmospheric carbon dioxide doubling scenarios. The Thornthwaite moisture index (an indicator of precipitation relative to evapotranspiration) was used to examine the effects of climatic changes on water resources in United States by McCabe et al. [1990]. The above studies, although very useful, provide a first cut estimate of the effect that climatic changes would have on freshwater watersheds. The uncertainty introduced in the estimates is due to the structure of the above mentioned models that incorporate simplified parameterizations of the hydrologic cycles. This paper presents the development of a model for the evaluation of the hydrologic and climate feedback responses of watershed ecosystems, using a detailed parameterization to describe the hydrologic and thermal processes of the terrestrial and aquatic portions of freshwater watersheds. The model presented in this paper is based on the Enhanced Trickle Down (ETD) model [Nikolaidis et al., 1988, 1989], which was modified to include an energy budget submodel and improved parameterization of the evapotranspiration, snow hydrology, and hydraulic conductivity components of the model. The model was calibrated and verified using field data from the W-3 watershed near Danville, Vermont. A conventional sensitivity analysis was also performed on the model parameters to determine which processes are most important. The aim of this research is to develop a tool that would reduce the uncertainties in evaluating the effects of global climate change on freshwater watersheds. This modified version of the ETD model represents an advance over the simple precipitation/soil moisture relationship studies presented earlier, and it is expected to provide better insight into the study of the effects of climatic change on watersheds.
MODEL DEVELOPMENT
The Enhanced Trickle Down (ETD) model is a mathemat-
The SPCC regulations entail numerous requirements for the storage of oil. The intent of this paper is to summarize several of the complex requirements associated with oil storage at a facility subject to the SPCC regulations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.