Derivation and analysis of morphologically relevant parameters from historical maps

摘要

Increasing morphological problems are being encountered with watercourses in central Europe, related to impacts on sediment regime with lack and surplus of material, higher bed shear stresses due to narrowing of river beds, and subsequent river beddegradation. Ecological deficits result from the tack of gravel bars, a missing of dynamic river morphology and a lowering of the groundwater table. Up to now, practical studies have generally used descriptive analyses of historical conditions of riversand their morphology (e.g. defining the morphology as braiding or meandering). This paper deals with the qualitative and especially the quantitative analysis of parameters derived from historical maps. Parameters such as river bed width, radius, slope and sinuosity are first described in a scaling context and then derived from two historical and the present situation at the river Mur in Austria. It is shown that this approach improves the quality of results based on historical maps and gives first ideasabout the solution of morphological problems.