Flood pulse concept and its application in river-floodplain system

As the fourth river-ecological theory after river continuum concept, flood pulse concept mainly states the ecological significance of lateral hydrological connectivity between river and its floodplains in the processes of river-floodplain system, with emphasis on the importance of flood pulse and the integrity of river-floodplain system. This paper mainly introduced the conceptual model of flood pulse, its main viewpoints, and application advances in river-floodplain system. Three aspects of flood pulse concept were applied. On the aspect of physiognomic processes, the 'dominant' discharge of channel form was particularly emphasized. On the biogeochemical cycle, nitrogen study took the first place, and flood pulse was considered as the principal driving force for the metabolism and biogeochemical cycle of river-floodplain system. As for the biological processes in river-floodplain system, most studies were focused on macrophytes and the animals represented by water birds and fish. It was indicated that intentional flood pulse should be advocated as a restorative management strategy for the improvement of plant productivity, management of exotic species, and restoration of overall biodiversity. In arid regions, the main issues for water birds conservation were the frequency and extent of flooding effects on the distribution of breeding habitat and/or refuge, and the water use across the landscape, which were of vital significance to the wetland water birds conservation in arid/semiarid areas of west Songhuajiang-Nenjiang Plain. The flood pulse concept was developed on the basis of the observations on neotropical Amazon river. With its application in other types of areas, the functions of other environmental factors excluding flood pulse sticked out, and the ecological effects of human disturbances on flood pulse were more and more visualized. Therefore, the study on the variations of floodplain processes under the coupling effects of flood pulse and other environmental factors with the disturbance of human activities should be strengthened, and accordingly, a universal model of relatively stronger applicability could be brought forward.