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Distributed GIS-based Hydrologic Modelling of Santa Catalina Island (CA), USA

A hydrologic modelling system based on GIS (Geographic Information System) technology has been applied to the island of Santa Catalina (CA) to assess the extent of runoff processes and to estimate soil erosion. Digital and analogic data for topography, vegetation cover, precipitation patterns and soil characteristics have been assembled, adapted and organised in a distributed database in ESRI Arc/INFO format. The processing modules based on AML (Arc Macro Language) scripts were used for the semi-automatic extraction of stream networks from the Digital Elevation Model (DEM) representing topography, to calculate the rainfall/runoff ratios according to the SCS (Soil Conservation Service) method, and to estimate soil erosion potential using an adapted version of RUSLE (Revised Universal Soil Loss Equation). Remote Sensing techniques of cluster analysis have been used to produce a vegetation map, while the extracted channel networks and related morphometric analysis addressed analytically the hydrologic characteristics of the island. Attention has been devoted to the conceptual formulation of the model as a process of semplification from the broader geomorphological system. An assessment of model validity is conducted by considering the several processing steps in some detail from both conceptual and informational perspectives, and RUSLE in particular is considered in terms of the risks associated with the generalisation of the model from the designed range of applicability.

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1 Abstract A hydrologic modelling system based on GIS (Geographic Information System) technol- ogy has been applied to the island of Santa Catalina (CA) to assess the extent of runoff processes and to estimate soil erosion. Digital and analogic data for topography, vegeta- tion cover, precipitation patterns and soil characteristics have been assembled, adapted and organised in a distributed database in ESRI Arc/INFO format. The processing modules based on AML (Arc Macro Language) scripts were used for the semi-automatic extraction of stream networks from the Digital Elevation Model (DEM) representing topography, to calculate the rainfall/runoff ratios according to the SCS (Soil Conserva- tion Service) method, and to estimate soil erosion potential using an adapted version of RUSLE (Revised Universal Soil Loss Equation). Remote Sensing techniques of clus- ter analysis have been used to produce a vegetation map, while the extracted channel networks and related morphometric analysis addressed analytically the hydrologic char- acteristics of the island. Attention has been devoted to the conceptual formulation of the model as a process of semplification from the broader geomorphological system. An assessment of model validity is conducted by considering the several processing steps in some detail from both conceptual and informational perspectives, and RUSLE in par- ticular is considered in terms of the risks associated with the generalisation of the model from the designed range of applicability. 5

Tesi di Laurea

Facoltà: Pianificazione del Territorio

Autore: Marco Ruocco Contatta »

Composta da 53 pagine.

 

Questa tesi ha raggiunto 228 click dal 28/08/2008.

 

Consultata integralmente una volta.

Disponibile in PDF, la consultazione è esclusivamente in formato digitale.