Yvonne Battiau-Queney

Recent shoreline mobility and geomorphologic evolution of macrotidal sandy beaches in the north of France

Abstract This paper examines shoreline mobility and sediment budget conditions on a sandy macrotidal coast with a well developed foredune. Aerial photographs and ‘bunker archaeology’ covering the last 50 years were analysed in order to determine the meso-scale evolution of Le Touquet beach, in northern France. Both methods show that shoreline retreat has been negligible or very slow and has been accompanied by an elevation of the foredune. DGPS cross-shore profiles show a balanced sediment budget over the last 7 years. Only a slight change of the beach face profile (0.2–0.5 m rise or fall) was observed while the foredune exhibited a sharper change. The French coast of the eastern English Channel differs from that of the French Atlantic coast which is currently being strongly eroded. The balanced sediment budget of the former is attributed to sand inputs from nearshore banks, which compensate exports due to longshore drift and to foredune development.

Constraints from deep crustal structure on long-term landform development of the British Isles and Eastern United States

Abstract It is assumed that some major landforms not easily explained by surface geology could be controlled by deep crustal properties. The concept was first applied in the British Isles and then to the U.S. Atlantic provinces. Both regions were affected by similar orogenies in late Precambrian/Paleozoic times and presently belong to the passive margins of the North Atlantic Ocean. In both areas, the pattern of rifting was greatly influenced by preexisting tectonic fabric of the continental crust. In the British Isles, pre-Mesozoic structures are cut obliquely by the Atlantic margin, while in the U.S. border, the present margin is nearly parallel to the Paleozoic sutures. The British Isles were affected by differential block-tectonics during the Tertiary. Examples are given of regional-scale landforms linked with crustal hinges. Recent data confirm the great heterogeneity of the crust beneath the British Isles. Each crustal unit has its own isostatic response according to the state of stress and its own dynamic equilibrium between rock resistance, erosion processes and uplift rate. In the Atlantic provinces of the United States, the regional physiographic framework is simpler, but allochthonous terranes thrust westward over the Grenville basement and shelf-sediments have buried some major discontinuities in the deep crust. Reverse faults associated with the NW-SE compressional stressfield are numerous but cannot explain regional-scale landforms like the Blue Ridge escarpment above the Piedmont. Rock control is not the direct cause of the escarpment. The Blue Ridge from reaches its highest relief where discontinuities in the deep crust interfere with surficial geological features. Ocean to continent creep processes are suggested to explain the sustained uplift of the Appalachian highlands and the relatively stable position of the mountainous front since middle Mesozoic times.

Using ArcGIS® Modelbuilder and Aerial Photographs to Measure Coastline Retreat and Advance: North of France

Abstract Chaaban, F.; Darwishe, H.; Battiau-Queney, Y.; Louche, B.; Masson, E.; El Khattabi, J., and Carlier, E., 2012. Using ArcGIS® Modelbuilder and aerial photographs to measure coastline retreat and advance: North of France. Coastal areas are naturally dynamic with changes occurring over periods of time. When the shoreline moves landward, coastal erosion becomes a serious problem, and the rate of change has to be calculated. Coastline retreat is one of the best indicators of coastal erosion. Here, the geographic information systems (GIS) platform (ArcGIS® 9.3.1; Esri software) is used to study the long-term (last 59 years) shoreline change in the area of Hardelot-Plage and Sainte Cécile–Plage (a north–south 14-km-long beach), in northern France. The primary aim of this study was to develop a methodology for calculating shoreline change using ArcGIS Modelbuilder and aerial photographs. Changes in 14 coastlines over the course of 59 years (from 1946 to 2005) were digitized and represented in ArcGIS 9.3.1 platform. Two hundred and ninety-two transects perpendicular to the shoreline were used to estimate coastal erosion and deduce the recession rate. The Modelbuilders (two models) created and used in this work are generic models that can be used for geoprocessing linear features. One model can be used to ascertain the intersection between linear features (transects and shorelines), adding a new field to the attribute table and calculating the geometry of the intersection points. A second model can be used to add a new field to the attribute table and calculate the distance on the transect lines between the linear reference feature and other linear features, in this study between the baseline (established adjacent to the series of shoreline positions) and the shoreline. The results show that the shoreline change rates between 1947 and 2005 along the Hardelot and Sainte Cécile coasts are generally negative; 82.2% of transects have values less than zero (i.e., retreat) and outside of the error margin (±10 m). Nevertheless the shoreline change shows successive phases of advance and retreat over the same period.

Geographical information system approach for environmental management in coastal area (Hardelot-Plage, France)

The use of geographic information system (GIS) minimizes the effort and improves the efficiency of numerical models. The GIS provides a platform for high capacity collection, management, manipulation, analysis, modeling and display of spatial data. The conceptual model is created using GIS objects including points, arcs and polygons so that it can accurately represent real world condition. According to the research problem, the geographical model is based on Hypergraph Based Data Structure method, and a conceptual data model has been created from which a physical data model was elaborated in ArcGIS9.3 platform. The groundwater modeling system (GMS) provides a powerful tool for hydrodynamics modeling and it is able to solve complex problems such as the groundwater flow and seawater intrusion. The sand-dune system of Hardelot-Plage (North of France) suffers from a lack of well-developed foredune. This problem is linked to the almost constant saturation of beach sand which is the potential source of dune nourishment. In the south of Hardelot, the coastline is slowly, but constantly retreating. To remedy this situation, a coupling between a GIS and GMS was adopted, in order to find the possible scenarios which could lower the piezometric surface in the concerned area and allow dune nourishment again. The GMS used supports the Modflow-2000 code. A direct approach to designing Modflow finite difference model is tedious and less intuitive, specifically for complex boundary and initial conditions. Therefore, a Modflow model can be developed either using a grid or conceptual model approach. The preparation of input data modeling is tedious and takes a long time. The model created in GMS was calibrated against the historical and observed water level data for 1995–2006. Then a hydrodispersive model (MT3d code in GMS) was launched for evaluating sea-water intrusion. The model was run to generate groundwater and salt concentration scenario during pumping tests.

The changing littoral. Anticipation and adaptation to climate change

This special issue gathers a selection of papers presented during Littoral 2016 in Biarritz organized by EUCC-France and the Coastal and Marine Union (EUCC). Entitled BThe Changing Littoral. Anticipation and Adaptation to Climate Change^ the conference allowed researchers and experts to take stock of scientific knowledge, new tools and methods of studying coastal zones (6 keynotes, 6 thematic workshops, 88 oral papers and 28 posters) (Battiau-Queney & Milon 2017). The conference addressed some fundamental questions about coastal environments and the different ways to reconcile nature and biodiversity conservation and sustainable development. It was also a noteworthy event to help French and European stakeholders present their Bsavoir-faire^ and exchange experiences about the practices and strategies of coastal management. Since decisions today will shape the future littoral, managers and policy makers have to adapt their strategy to the increasing vulnerability of coastal areas and to take account of the possible midand long-term effects of management practices. To do this they need a good knowledge of coastal systems and it is fundamental to disseminate the results of current research amongst managers, policy makers and the general public. Through Littoral 2016, EUCC-France and its partners have contributed to this objective. Research topics addressed in this special issue