Gis-based morphometric analysis of two major watersheds, Western Crete, Greece

Watershed analysis based on a geographic information system (GIS) was carried out in two agriculturalwatersheds in the central area of Chania prefecture on the is land of Crete, Greece. The digital data for deriving geomorphometric parameters significant for the evaluation of watershed condition were extracted from topographical, geological, hydrological and hydrolithologicalmaps, and were updated by Landsat-ETM'satellite imagery. Geomorphometric parameters such as drainage density, stream frequency, hypsometric integrals and hypsometric curves, especially at the sub-basin level, enabled an understanding of the relationships among the different aspects of the drainage patterns and their influence on landform processes, drainage, and land erosion properties. Geomorphometric parameter analysis coupled with fractal analysis and statistical analysis of the stream tributaries revealed that the two watersheds have undergone severe erosion in the past, and are still susceptible to surface erosion, while their development has been significantly affected by geomorphological and lithological factors such as faults, slope, and rock permeability.