A typology of Corsican headwater catchments based on multivariate analysis of morphometric characteristics

Abstract

This article is a study of headwater catchments and streams that aims at a first morphological typology of such catchments for Corsica island. Such typology offers a base for various studies or assessments regarding, for instance, water management, geological hazards assessments or faunal and/or floral species conservation. Corsica island comprises 120 peaks over 2000 m above sea-level. Herein, the characteristics and developments of 83 Corsican headwater catchments found above 1200 m above sea-level are evaluated using a digital elevation model, a principal component analysis and a hierarchical cluster analysis based on 14 morphometric parameters. It appears that 65.31% of the data’s total variance is clarified by the first three principal components. On the first principal component maximum elevation, mean elevation, mean slope and Melton ratio are found opposed to area and perimeter. Moreover, a latitudinal gradient on the first principal component is confirmed by the supplementary variable latitude’s coordinate. On the second principal component the form factor is opposed to the Lemniscate ratio. The most representative catchment points are best highlighted in terms of the catchments of the seven main streams. The cluster analysis allows to divide the catchments into four groups or types, unequivocally reflecting the first principal component and emphasising the comparable results for the two analyses. These four types of catchments are numerically characterised by four main parameters, which are area, Melton ratio, mean elevation and mean slope. A first morphological typology for Corsican headwater catchments is proposed in accordance to both principal components and cluster analyses.