ANALYSIS OF INFILTRATION RATES OF SOILS ON THE INNER SLOPES OF THE LAKE SFÂNTA ANA CRATER

The present study consists of the comparative analysis of infiltration rates of soils under different land-cover conditions (dirt trails, grass plots and different types of forest stands) on the inner slopes of the Sfânta Ana crater, the catchment area of Lake Sfânta Ana in Romania. According to historical data, the depth and the surface of Lake Sfânta Ana have been undergoing significant changes during the last century, it lost in depth and the surface area shrunk approximatively 1,5 hectares. The losses are considered to be the consequences of the sedimentation as a result of the inflow processes from the catchment area, reduction of water level and eutrophication. The assessment and comparative analysis of steady infiltration rates of soils under different land-use categories in the catchment area were carried out to identify the possible sources of generation of surface flows responsible for sediment transport towards the lake using In Situ determinations with Double Ring Infiltrometers (DRI). Statistically significant differences were found between samples collected from grass plots, forests and the dirt trails, and within different forest stand structures. Results show that dirt trails and grass plots can be held responsible for the generation of surface flows. The main cause of low infiltration rates is soil compaction. Different forest stands are characterized by steady infiltration rates with high values and therefore provide effective protection. High forest coverage must be maintained in the crater, the problem of soil compaction on grass plots and dirt trails must be addressed.