A dynamic connectivity metric for complex river wetlands

Abstract

Surface water connectivity between rivers and floodplain lakes is essential to maintain biodiversity and ecological functioning in floodplain wetlands. This study proposes a method to analyze the spatial and temporal connectivity using hydraulic modeling and freely available remote sensing data. A novel dynamic connectivity metric introduced here accounts for the entire flow path, which can be a substitute for flow connectivity indicators and statistical connectivity indicators. The metric allows comparing the hydrological connectivity between different phases of a flood event, between different flood events, and potentially between different catchments. The method was applied to the Northern Lakes of the Narran River catchment in New South Wales, Australia. The results indicate that there is no clear transition in the connectivity between different stages of a flood event in the flat Narran River wetland compared with other wetlands connecting to deeper river channels. Thus, the proposed metric brings a more comprehensive observation on hydrological connectivity in floodplain wetlands than previously developed metrics, which is expected to further support ecological and water management studies in river catchments.