Hazard of highways by water induced soil erosion in Saxony-Anhalt / Gefährdung von Autobahnen durch Wassererosion in Sachsen-Anhalt

Thunderstorms with heavy rainfall induced flooding of motorways in Saxony-Anhalt repeatedly. Such events are usually connected with soil erosion on fields near the roads and lead, apart from loss of soil fertility, to damage on infrastructure and expose traffic to danger. Endangered street sections are there was surface runoff as a result of heavy rain could be able to trespass a lane. The aim of the investigation were the detection of both prospective trespassing points and street sections of highest risk at the motorways A 2, A 38, A 14, A 9, A143 and the national highway B 6n (up to Güsten). Under usage of digital elevation data and modeled runoff pathways 215 prospective trespassing points have been detected. Data of land use, approximated erosion risk and content of surface runoff are used to find the street sections of highest risk. The approach was exemplarily validated using field observations. It shows that the approach is useful for a first priority assessment of endangered street sections. Limitations mainly result from spatial resolution of digital elevation data. Before planning real measures against flooding and erosion the results have to be checked by field investigations and use of higher resulted digital elevation data.