FEDER - MARC SA - CHERLOC PROJECT
Kohesio
ENTREPRISE MARC SA
The world's coastal landscapes are constantly being transformed by the construction of infrastructure (seawalls, jetties) which make it possible to meet the growing demands for economic activities. The natural coastal environment is fragmented by human constructions encroaching on the ecological habitats of the intertidal zones. This character is particularly marked on the Channel coasts where the tidal range is high. Until recently, the response to a marine submersion event was approached from a pure engineering angle with the construction of a new infrastructure in response. Over the past ten years, a paradigm shift has taken place by integrating nature and society into the technical approach to coastal projects. In the Netherlands, the Building with Nature concept is emerging through a very large-scale, full-scale experiment (Sand Motor) in order to protect a coastal stretch using large-volume sand replenishment and to provide a gentle, long-term response to the problem of coastal erosion. In Northern Europe, for example, buffer zone strategies allow the progressive construction of sedimentary reservoirs and wetlands, favorable to the ecosystem, and playing a protective role until the next 100-year storm. The variables and conditions of the environmental system are integrated from the earliest considerations of the project, taking into account long-term changes at the limit of the engineering time scale. Here, the ecosystem services are already of great magnitude through the function of mitigating marine submersion but also through the creation of leisure and recreation areas, through the formation of a rich ecosystem on the coastal fringe, through the preservation of fresh water tables. The main objective of this project is to create and study two pilot sites in the Normandy region by integrating two types of artificial blocks into existing dikes (Cherbourg, Ouistreham) through approaches of social acceptability, biodiversity and coastal engineering. This multidisciplinary project involves a regional maritime works company (MARC SA), a design and research office (ARTELIA), an engineering school (ESITC Caen), three research laboratories from the University of Caen (CERREV, BOREA, M2C) and Ports de Normandie. Severe hydrodynamic conditions involve the use of concrete blocks (BCR, ACCROPODETM) in place of natural riprap in order to ensure increased stability of the defense work and also to limit crossings. A shell block (Double-Cube) was developed in the M2C laboratory. This block has many advantages (performance, ease of installation, multi-use), however it has not yet reached the industrial demonstrator stage. Likewise, ARTELIA has designed a new generation of foot blocks for embankment dykes: AccroBermII (ABII). The ABII foot block replaces the foot stop (stabilization of the carapace) thanks to its circular shape. Due to its hollow shape, its stability is also ensured by filling with riprap. Several environmental advantages then emerge (limited impact on the seabed, limited indirect environmental impacts, interactions with biodiversity). A comparative study of the biodiversity of a coastal stretch protected by artificial or natural riprap will be carried out through ecosystem approaches on macroflora, macrofauna and microalgae biofilms. CERREV will question the reactions of the populations of the Region regarding the potential installation of these blocks. Presenting the consequences of flood risks may not necessarily raise awareness or accept potential remediation. CERREV will analyze these reactions in order to facilitate the choice among the possibilities.
Smarter Europe / Research and innovation / Research and innovation activities in private research centres including networking