This thesis deals with the use of engineered log jams at small and large rivers in southern Bavaria. Engineered log jams are stable large wood structures that consist out of logs, root logs, root wads and gravel which are used in river restoration to prevent the lack of dead wood. In doing so, they meant to provide both greater flow dynamics and increased habitat availabil- ity. The aim of the work is to document structural measures with engineered log jams on the Inn River in the district of Mühldorf on the Inn and on the Attel River in the district of Ebersberg and to use the findings from the measures to develop general criteria and recommendations for actions for the use of engineered log jams. Selection criteria include a near-natural sedi- ment regime, a focus on neuralgic sites, a minimum spatial extent, ownership of the land, safety distance to infrastructure and settlements, geological conditions, transport routes, and accessibility for construction site vehicles. When implementing structural measures with engi- neered log jams, a sufficient amount of dead wood should be installed, the size of the log jams should be adapted to the watercourse, materials should be procured in advance, the time pe- riod should be chosen appropriately, experienced workers should be recruited for the work in and around the water, arrangement with residents is recommendable, the watercourse mainte- nance adapted to the goals of the structural measurements and the whole process should be supported with a watercourse ecological monitoring. Using these findings and the GIS, addi- tional locations in the region suitable for the installation of engineered log jams were identified. In addition, discharge measurements were taken on the Attel River to determine variances concerning the flow, depth, and width due to the installation of ELJs. Despite any challenges during the construction measures due to the geological conditions on the Inn River caused by the upcoming Flinz, the large amount of dead wood required, and the transportation routes, two bar apex jams at the Inn River and eight bar apex jams and groyne-like ELJs on the Attel River could be successfully constructed. Fortunately, on the Inn River and the Attel River, sed- imentation processes and accumulations of dead wood can be already observed after the fi- nalization of the construction measures. In general, ELJs are a diverse and secure method to bring large amounts of dead wood into the water body to achieve positive effects on the water ecology through the dead wood. Thus, the use of ELJs should be further promoted in southern Bavaria.
«
This thesis deals with the use of engineered log jams at small and large rivers in southern Bavaria. Engineered log jams are stable large wood structures that consist out of logs, root logs, root wads and gravel which are used in river restoration to prevent the lack of dead wood. In doing so, they meant to provide both greater flow dynamics and increased habitat availabil- ity. The aim of the work is to document structural measures with engineered log jams on the Inn River in the district of Mü...
»