SIMULAZIONI NUMERICHE DI ACQUIFRI CARBONATICI IN AREE CORRUGATE: APPLICAZIONI AL SISTEMA IDROGEOLOGICO DELLA VALNERINA (ITALIA CENTRALE)

This thesis is subdivided into three parts. In PART ONE a description is provided on a bibliographic basis of the physical geological and hydrogeological features of the Nera basin. A conceptual model is developed for the entire hydrogeological basin upstream from Torre Orsina. Furthermore, a proposal is made for its subdivision into five subsystems considered as hydraulically isolated from each other. For each subunit hydrogeological budgets and synthetic schemata have been made. In PART TWO of the thesis the principles of hydrogeological modeling are treated with a brief outline of theoretical references, a broader description of the computer code adopted, the principle problems related to the construction of numerical models in general and for corrugated areas in particular. A schematic description is given of the relationships among units in the stratigraphic succession, the hydrogeological complexes and the layers for the numerical model. An illustration is given of the simplifications and the hypotheses leading up to the representation of multi-layer aquifers by means of a succession of superimposed horizontal layers which takes into account also the unsaturated portion of each aquifer. In PART THREE the models are presented of the two subsystems of the Valnerina hydrogeological basin. For each a detailed description of the conceptual reference model is given, then the numerical model and lastly the results of the permanent and transitory regime simulations. Sensitivity analysis allows an evaluation to be made of the effects of hydrodynamic parameters on the model. Lastly, a possible application for one of the models is proposed for two water resource management hypotheses. A more detailed summary of this thesis is set out in Chapter 10, "Summary and Conclusions".