Simulation of vegetation and relief induced shadows on rivers with remote sensing data

Rivers are the lifelines of our environment. For this reason they are always in the focus of environmental studies. For the assessment of the ecological status of rivers the member states of the European Union have developed different monitoring programs and approaches. The shadowing of a river affects the temperature of the water and also the energy balance of the water body. Therefore changes in temperature also influence the biological and chemical status of rivers and lakes. The main objective of this study is the simulation of the shadowing of a section of the river Freiberger Mulde for a full year. This ensures that effects of different sun positions over the year (azimuth, elevation) and also local topography conditions in the close environment of the river section are taken into account. For all analyses a digital surface model and a digital elevation model with a geometric resolution of 2 m is available. The result of this simulation is a raster layer which represents the theoretical annual hours of shadowing of the river section. The results indicate a decrease of illumination of partly more than 80 %. In future this information can be expanded by means of further affecting factors such as the consideration of the phenological status of deciduous trees in the riparian zone.