Coastbusters: Investigation of Ecosystem Based Coastal Stabilisation Solutions
Type:
Presented during:
WODCON XXII - Enhance the Harmony between Dredging and Ecology
Authors:
T. Sterckx, E. Lemey, M. Huygens, J. Fordeyn, B. Groenendaal, D. Delbare, T. Vanagt, B. Pycke, A. Semeraro and T. Mascart
Abstract
"Conventional coastal protection solutions such as dykes and embankments are increasingly being challenged by changes in sea level rise, more aggressive climatic conditions, land subsidence, erosion of beaches and altered sediment flow. Maintenance of these conventional structures will become unsustainable; hence, innovative alternatives are necessary to guarantee coastal resilience. The Coastbusters project aims to develop three nature-based solutions for sustainable coastal protection. These solutions will create new habitats based on known 'biobuilder species' in the form of biogenic coastal reefs. The purpose of the reefs is to induce natural accretion of sand, attenuate storm waves and reinforce the foreshore against coastal erosion, thus, adding to coastal protection. Three key biobuilding concepts were identified to be tested to strengthen conventional coastal engineering: (1) Tube-building polychaete worm reefs (Lanice conchilega), (2) Marine flora fields (seaweed and seagrass) and (3) Bivalve reefs (mussels and oysters). Based on a critical assessment of the actual state of the art, adapted innovative designs are evaluated in an integrated feasibility analysis prior to further step up pilot projects in the field. The created biostabilisation power of the biogenic reefs is tested in both laboratory experiments and in-situ pilot projects in front of the Belgian Coast. For each of the three concepts, the following generic goals were identified: (1) The organism survives the dynamic conditions of the foreshore and maintains its ecological functions - environmental survivability status. (2) The reef, built as a specific biogenic structure, is stable and creates ecological added value within the local coastal ecosystem - ecological added value (ecosystem services). (3) The natural reef develops in such a way that local sedimentation and natural stabilisation of the foreshore occurs - technical valorisation value (adding to coastal protection). As for each of the three concepts the same 'success' criteria are formulated, a uniform monitoring and evaluation approach is set up in an integrated way. The project was awarded an innovation grant from the Flemish government in March 2017 and runs for 3 years. This paper describes the selection process of the concepts including their design, development (from laboratory tests into a pilot scale setup in front of the Belgian coast), deployment and monitoring."
Keywords: Nature based solutions, Sustainable coastal protection, Ecosystem based design, Environmental&ecological dredging, ecosystem services, biogenic reefs.