Precipitacions i escorrentia a les conques torrencials de Mallorca

Abstract

The aim of the thesis is to study the flood events and the flood peaks originated in the torrential catchments of Mallorca. The importance of flooding in the Mediterranean area is well-known. These natural phenomena are everyday elements of life and, until recently, were an usuful tool for agricultural societies. At present, and due to the demographic and urban changes in the Mediterranean basin, floods have become a risk factor that should be studied to prevent damages, the loss of property and human lives. The study of peak flows involves analyzing precipitation, as a factor that triggers flood events, and the main features of the selected watersheds, features that can increase or decrease the flood peaks. Since in Mallorca the most widespread form of flooding is the flashflood, there has been a research form a methodology about how to study flash floods. A characterization of rainfall and runoff in Mallorca has been developed. Data about flows is poorly known due to the lack of an extended gauging network and the use of a post-event study method was applied in order to calculate the flow levels. Post-event research has been widely accepted as an adequate system to do this kind of research. A field work research was done to find sections with good high water marks, marks that provide information about the level reached by the water at the time of the flood. This methodology has been applied to two basins of the Serra de Tramuntana range, basins that, in the first decade of the 21st century, have been affected by torrential episodes of medium intensity.