Morphodynamic Evolution of the Zackenberg Delta in North-East Greenland

The present study focuses on a quantification of the morphologic evolution of the Zackenberg delta in North-East Greenland. The time scale of this evolution ranges between days, events and decades. The study describes the impact of extreme discharge events on the delta morphology (delta plain and delta front) and schematize the fluxes of sediment and morphologic change between the different parts of the active and abandoned delta lobes. The extreme river discharges cause the main changes on the active delta lobe leading to channel shifts. Besides, average river discharges transport sediments to the fjord and can locally lead to lateral channel migration on the delta plain. Wave action dominates the changes on the abandoned delta where a spit migrates on the delta plain and partly closes the inner delta plain for wave action. This creates a salt marsh close to the former Zackenberg distributary. A conceptual sketch summarizes the fluxes of sediment and morphologic change between the different parts of the active and abandoned delta lobes. These findings bear insights on extreme events in Arctic coastal environments with impacts including damage of local infrastructure on delta plains.