Riego

AVSWAT 2000
Biesbrouck B., Wyseure G., Van Orschoven J. and Feyen J.

February 2002 Katholieke Universiteit Leuven (K.U.Leuven) Laboratory for Soil and Water Management (LSWM) Vital Decosterstraat 102, B-3000 Leuven, Belgium

The e-manual is based on the theoretical documentation and user’s manual ‘Soil and water assessment tool User’s Manual, version 2000’ (Neitch et al., 2001) and‘ArcView interface for SWAT2000’ (Di Luzio et al., 2001), publications published by the USDA-ARS the Texas Agricultural Experiment Station, Temple, Texas, USA. The web-based version of the manual was developed as a didactic tool for the undergraduate and graduate students of the Faculty of Agriculture and Applied Biological Sciences of K.U.Leuven, following the Surface Hydrology course, and the alumni ofthe Interuniversity Programme in Water Resources Engineering (IUPWARE, K.U.Leuven and VUB). The e-manual is intended to guide students, engineers and scientists in running the model. Combination of the software and theoretical e-manuals enables to explain the underlying theory of the software steps one has to go through running the model. The advantage of the web-based form is that user’s can gothrough the theoretical and software manuals and sample problem at their own pace, as frequent as they want, without the need of an instructor.

Forword
Environmental awareness contributed lately considerably to the interest of better understanding the hydrology of watersheds, and in particular in understanding how human interferences alters the water cycle, quantitatively and qualitatively.Numerical models in combination with timeseries of catchment variables, to which those models are calibrated and validated, helps to grasp with the mind the underlying processes, the interaction of the hydrologic cycle with the environment and the way changes in land use and climate affect catchment hydrology. An understanding of the hydrologic processes is a necessary prerequisite to the developmentof rational designs and for good management of the water resources. There are, of course, many model codes that describe hydrological processes with varying degrees of mathematical analysis and number of equations. Independent the type of model, application of all hydrologic models require more or less the same steps, i.e. schematization of the catchment to a structure that is processable by amodel code, selection of the most appropriate code, collection of input data, model calibration and validation, and postprocessing of the simulation results. The AVSWAT model code was selected to illustrate the different steps the user traditionally goes through before a model can be used in a predictive way. The main reasons that the AVSWAT model code was selected is that it belongs to the publicdomain and is freely available on the WEB, the model is semi-mechanistic and spatially distributed, able to describe the water flow, sediment and nutrient (pollutant) transport of mainly rural catchments. The different steps are illustrated using the hydrologic information of a real case study, the watershed of the river Nete, a medium-sized catchment (390 km2) in the north-east of Belgium. Thee-manuals only illustrate how the AVSWAT model code processes the water flow in the different components of the hydrologic cycle. The user is guided automatically through the theoretical and software manuals, and the e-manuals are structured in such a way that the user at any moment can switch from the theoretical to the software manual and vice-versa. The theoretical manual provides information onthe steps in the software manual. Furthermore the manuals are equipped with an online demonstration facility, illustrating the movements of the mouse in the different steps. In going through the manuals the AVSWAT model is applied to the case study catchment, illustrates how the catchment is structured to be processable by the model, prepare input, run the model and analyses the model output....