Impact of hilly-mountain watercourses on skid roads/trails, case study

Abstract

Numerous authors have written about the problems of the occurrence of erosion processes on primary and secondary forest traffic infrastructure, emphazing their importance in the formation of sediment, as well as their negative impact on the watercourses near the both types of forest traffic infrastructure. Secondary forest traffic infrastructure may have an especially negative impact on watercourses. It is built with low technical criteria, so if not repaired, it is highly likely that it will become a source of sediment (Bajrić, 2012). Previous practical experience in the forestry in FB&H show that the rehabilitation of secondary forest traffic infrastructure is carried out only occasionally, or it is completely left out. Besides that, superficial approach to designing secondary forest traffic infrastructure in the conditions when a developed hydrological network is present may cause serious and negative consequences for watercourses. The introduction of forest mechanization in the phase of timber transportation increases the production of sediment from secondary forest traffic infrastructure. Meghatan and Kidd (1972) state that erosion is the most common phenomenon on the surface of secondary forest traffic infrastructure due to large longitudinal slope and the impact of the forest mechanization wheels. This research shows that out of 10 intersections of secondary forest traffic infrastructure and watercourses there is a significant impact of watercourses that of forest mechanization on 6 intersections, while in 2 cases that impact is very significant and it is neccessary to repair the secondary forest traffic infrastructure in order to enable the mechanization to pass safely. This research shows that out of 10 intersection positions of secondary forest traffic infrastructure and watercourses, at 6 we have a significant impact of water flow which makes it difficult for the mechanization to pass, while in 2 cases this impact is very pronounced and it is necessary to repair them in order to enable the mechanization to pass safely. Out of the total lenght of 13,469 m of watercourses in the research area, secondary forest traffic infrastructure has a strong to extreme impact on 7,451 m (55.32%) of the watercourses. An extreme impact of secondary forest traffic infrastructure on watercourses has been registered on the length of 1,101 m or 8.17% of the watercourses in the reaearch area, on which there has been a complete change of the natural direction of water flow. The obtained results show that the no rehabilitation measures of secondary forest traffic infrastructure have been carried out in any of the three compartments which have been selected for the research. The focus of the results of this research is on the intersections between secondary forest traffic infrastructure and watercourses in the conditions of dense hydrological network, where it is neccessary to construct temporary culverts. They are made of flexible plastic pipes. Quality solution for secondary forest traffic infrastructure crossings over hilly mountain watercourses minimizes the risk of the occurrence of erosion processes on secondary forest traffic infrastructure, which can cause ravine flows or its surfaces may become a torrent bed in extreme cases.