The geomorphic activity of forest roads and its dependencies in the Tatra Mountains

Forest roads in mountain areas have a significant impact on the changes of water circulation and cause the development of numerous erosion and accumulation forms. The aim of the study was to investigate the magnitude of geomorphic changes within forest roads, determine the factors influencing it, and assess the rate of erosion/accumulation within these roads. Geomorphological mapping of forest roads (6.2 km) was conducted. Roads were divided into homogeneous morphogenetic sections, and a set of parameters was measured for each of them. In order to determine the main factors responsible for relief changes within the roads, the Principal Component Analysis was used. The t-test for two independent samples was also used to check the influence of the bedrock type on the geomorphic changes within roads. Repeated cross-sectional profile measurements were conducted to determine the intensity of erosion and accumulation processes. Our results show that the magnitude of geomorphic changes within forest roads mostly depends on the presence of subsurface flow interception from the cutslope, which in most cases occurs when a road is constructed across a convergent slope area. The strength of the bedrock also has a significant impact on relief transformations, which is expressed in the higher amount of accumulation and erosion features, and higher dissection depths within weaker rocks. The highest annual rate of road deepening is 10 cm yr−1.