Sustainability of the multi-channel system in the Westerschelde under influence of dredging and disposal

Zheng Bing Wang

Monday 29 june 2015

16:00 - 16:12h at South America (level 0)

Themes: (T) Special session, (ST) Scheldt Estuary physics and integrated management

Parallel session: 3J. Special session: Scheldt Estuary physics and integrated management

The Westerschelde estuary is pre-eminently a system where sustainable coastal management is required. It serves as navigation channel to the Port of Antwerp, but it is also a Natura 2000 area. Its multi-channel system is an important natural characteristic. Deepening and maintenance of navigation channels are crucial human interferences. The disposal of dredged sediment can jeopardize the multi-channel system and thus the ecological value of the estuary. This paper presents an ongoing study meant to improve our knowledge on the morphological development of estuaries for supporting estuarine management considering accessibility for navigation and the ecological value. We focus on the question whether a multi-channel system in the Westerschelde can be sustained under pressure of future deepening and maintenance. Therefore, we explore the robustness of the system and try to quantify the threshold for which the system switches from a multi-channel system to a single-channel system. This is done by considering morphological development on different spatial scales, ranging from channel-shoal interaction to full estuary scale. Furthermore, the effects of sand transport and mud transport will be considered separately. The study is based on a combination of analyses of field data, theoretical analysis, process-based modelling with idealised schematisations and with complex geometries. The results of the study will directly be applied for developing better strategies for disposal dredged sediments, supporting decision making concerning sand mining and further deepening of navigation channels, and for monitoring the effects of human activities on the morphological development in the estuary.