GIS AND DIP'S APPLICATION TO THE GEOMORPHOLOGICAL ANALYSIS OF FLUVIAL DYNAMICS. A PRACTICAL CASE: THE RIVER JARAMA IN MADRID (SPAIN)

摘要

In this paper, morphological changes of Jarama river and its tributaries, Henares and Manzanares, are studied in an area near Madrid (Parque del Sureste, Madrid). Aerial photographs from two different periods, 1956 and 1999, have been analysed using Geographical Information Systems (Arc View 3.2) and Digital Image Processing (Erdas Imagine 8.4) software. In each period, channel length, fluvial space and riparian area, sinuosity index and meander shape have been measured, as well as the increase of rip-rapped reaches and gravel extractions areas. The results show a significative reduction of the fluvial space in the study area (from 1713 ha in 1956 to 936 ha in 1999) due to agricultural or industrial occupations and gravel mining. Simultaneously, an increase of channel realignment and rip-rap works have been observed. The GIS and DIP software used in this work seem to be very useful tools to quantify morphological and land use changes, allowing the evaluation of spatial and temporal trends in river channel dynamics.