Applicability of hydromorphological monitoring data to locate flood risk reduction measures: Blanice River basin, Czech Republic.

This paper presents a new methodological approach, using hydromorphological monitoring data from river networks, to identify stream elements that may negatively influence the course of floods, as well as elements suitable for modifications that will reinforce the natural retention potential of the floodplain. The approach uses data derived from hydromorphological monitoring that conforms to the EN 14614 standard "Water quality--Guidance standard for assessing the hydromorphological features of rivers." Four major aspects of stream modifications that can potentially affect the course and consequences of floods, and that can be derived from hydromorphological monitoring, were identified. These are: (1) modifications that increase the speed of runoff, (2) modifications that restrict the retention potential of the floodplain, (3) potential obstacles to the flood course, and (4) improper alterations of stream route modifications. A GIS is used to identify and locate these critical aspects of stream and floodplain modification. This method was applied in the Blanice River basin, an area in central Europe hit by a severe flood in August 2002. The critical modifications identified were compared with geomorphological mapping to display the different effects of individual types of modifications.