Analysing Hydrological Regime of a River Network in a Mediterranean Basin Using Multivariate Analysis

This paper presents a study aimed at analysing the hydrological regime of a number of stream reaches using Hydrological Indexes (HI), which describe magnitude, frequency, duration, timing and rate of change of hydrologic conditions. The Indicator of Hydrological Alteration Indexes software (IHAs) was used to calculate 33 HIs in 9 gauging stations of the Candelaro river basin (S-E Puglia). Daily streamflow data recorded over a long time period were used to calculate the HIs, which depend on some basin characteristics: climate, topography, land use, management, soil type, and other factors. The Principal Component Analysis was applied to these 33 Indexes to identify subsets of HIs that describe the major aspects of regime while minimizing redundancy. The authors report that streams draining small watershed are mainly described by duration, variability and predictability indices. These HIs can adequately represent the major aspects of Mediterranean streams flow regime.