Forests and Their Hydrological Effects in Mediterranean Mountains

This article considers the effects of forests on the hydrology of a Mediterranean mountain area. Variations of climate factors, discharge, interception, and water table depth in the San Salvador forested experimental catchment in the Central Spanish Pyrenees were studied and the results compared with those from two deforested catchments. The hydrological response of the San Salvador catchment had the following properties: 1) it had both smaller peak flows and smaller low flows than the deforested catchments; 2) most rainstorm events produced almost no discharge response; 3) the intensity of precipitation had no influence on the magnitude of peak flows; and 4) depth to the water table was the most important factor in the relationship between precipitation and discharge. These results confirm that forest conservation reduces floods and soil erosion, particularly on steep slopes.