Runoff and sediment production in a mediterranean basin under two different land uses

Abstract

This study analyses the influence of two different land uses on the hydrology of the Vernegà experimental basin between the years 2005 and 2009. It is located in the Northeast of the Iberian Peninsula and is influenced by a Mediterranean climate, with an average annual rainfall of 646 mm. The study of rainfall distribution in the 1982 to 2009 period shows that the majority occurs during autumn, winter, and spring representing 33.2%, 25.5%, and 25.7% respectively of the total annual rainfall. Surface runoff is concentrated from October to June. Between 2005 and 2009, total runoff was 242.38 mm at the "Bosc" gauging station, which drains an area of 1.60 km2, and 298.54 mm at the "Campàs" gauging station, which drains an area of 2.57 km2 and is located at the outlet of the basin. More than 80% of the total surface runoff yielded during the study period corresponds to the 2005-2006 hydrologic year. Finally, Campàs gauging station registers a higher total runoff than Bosc gauging station. Part of this phenomenon may be due to the interception of rainfall and plant biomass in the forested area of the basin. In relation to the sediment yield, an overall increase in the two basins has been detected. Recent forest management practices undertaken in the catchment area are considered to be one of the most important reasons for this change.