Morphodynamics of a 1000-year flood in the Kamp River, Austria, and impacts on floodplain morphology

This paper investigates the, impact of a 1000-year flood in August 2002 on floodplains and valley morphology of all Austrian Mixed alluvial bed river. Dicharges with a recurrence interval between 500 and 2000 year., used distinctive overbank scouring and material deposition in the floodplains. After the 1000-year flood, those morphologically affected areas were at random intervals (documented over the whole longitudinal profile. In addition to overbank erosion in curved sections (cut-offs) river bed locally widened, floodplain stripping occurred and local overbank scours were documented along Straight parts of the river. A Ill model, combined with field measurements, was Used to analyse the. cause of these erosional landforms. Based on the modelled hydraulic conditions for a one-year flood (30-78 m(1) s(1)) and the catastrophic 2002 event (700-800 m(1) s(1)), the numerical results allowed a cause-effect study with 19 parameters. Deterministic and statistical analysis (ANOVA, discriminant analysis) showed that the morphodynamic effects of the 2002 flood were influenced by the variability of valley morphology of the Kamp River, which led partially 10 supercritical flow during flood (constriction. These processes were in some cases also anthropogenically influenced. Lateral constriction and expansion of the valley geometry over distances led to scouring, and aggradation within the inundated areas during the event. These morphological features Were therefore responsible for the elongated scour holes in the floodplains. Copyright (C) 2009 John Wiley & Sons, Ltd.