Daniel Delahaye

• Professor
• University of Caen Normandy

Depuis le milieu du vingtième siècle, les paysages bocagers du nord-ouest de la France subissent d’importantes mutations. Sous l’effet de la transformation foncière des exploitations agricoles, les parcellaires sont rationnalisés, remembrés et les haies sont fréquemment arasées. Ces mutations ont pour répercussion de multiplier les transferts hydro...

Land use and landscape structure play an important role in the functioning of flash floods on the arable plateaus of northern France. Landscape structures have changed considerably over the last decades with an increase in runoff-producing surfaces and an enlargement of the plots. This evolution results in an increase in runoff volumes accompanied...

Fire regimes are important components of environmental dynamics, but our understanding of them is limited. Despite recent advances in the methodologies used to remotely sense and map fires and burned areas and new case studies that shed light on local fire use and management practices, the scientific community still has much to learn about anthropo...

Tout en maintenant les traditions de son terroir, réputé pour l’excellence de son lait et de ses savoir-faire, Isigny Sainte-Mère est à la pointe de la performance industrielle et de la traçabilité. Aujourd’hui, elle se développe à l’export et conquiert le marché chinois...

Les transferts hydro-sédimentaires issus des processus de ruissellement érosif des sols agricoles génèrent de multiples aléas au sein des hydrosystèmes (érosion des sols, pollution de l'eau, inondations aux exutoires, etc.). Dans les espaces bocagers, ces transferts ne sont pas rares et les mutations paysagères enregistrées au cours des 70 dernière...

Soil erosion is one of the major environmental threats that is related to agricultural land use in France, especially in Normandy, where agricultural land occupies 65% of the territory. This region is located on a chalky plateau that is affected by the karst phenomena. One of the characteristics of this karst landscape is the low proportion of surf...

Many authors focus on the concept of sediment connectivity to predict the sedimentary signal delivered at catchment outlets. In this framework, the sedimentary signal is seen as an emergent aggregation of local links and interactions. The challenge is then to open black boxes that remain within a sediment cascade, which requires both accurate geomo...

There is fragmentary knowledge of the hydrosedimentary dynamics of rivers in Normandy during the installation of numerous watermills dating from the MiddleAges and onwards. The rates of erosion and sedimentation that have occurred in Norman Rivers over the last two millennia are poorly understood as are the anthropogenic and climatic forces which h...

En Basse-Normandie, la connaissance des dynamiques hydrosédimentaires des cours d'eau avant et pendant la mise en place des nombreux aménagements hydrauliques depuis le Moyen-âge est très fragmentaire. On sait peu de choses sur les rythmes d'érosion et de sédimentation qui ont joué dans les cours d'eau bas-normands au cours des deux derniers millén...

There is fragmentary knowledge of the hydrosedimentary dynamics of rivers in Normandy before and during the installation of numerous watermills dating from the Middle Ages and onwards. The rates of erosion and sedimentation that have occurred in Norman rivers over the last two millennia are poorly understood as are the anthropogenic and climatic fo...

Hy drosedim entary fluxes that run from agricultural plots down to the water stream s are currently associated with m any social, econom ic and env ironm ental issues such as diffuse pollution, soil infertility, soil loss, floods, etc. While the genesis of these transfers are well-known at the scale of the agricultural plot, flow dy nam ics occurri...

In Sudanian savannas, frequent fires are required to maintain a mix of trees and grasses. After a century of long conflict over fire utilisation and resource management, arising from colonial scientists reacting against traditional practice, fire has become a management tool used to shape tropical vegetation. Many examples show that fire is allowed...

Some “flash floods” with high suspended content affect at the end of spring and during the summer some parts of the Paris Basin, in north-western France, causing dramatic human and property damage: 269 events have been induced by 79 high rains between 1983 and 2005. Such events are the most dangerous form of floods encountered in this area because...

In the region of Basse-Normandie, the process of “agricultural modernisation” started in the 1950s has led to an unprecedented reorganisation of rural spaces and landscapes. The irregularity of the fabric of land plots was corrected by successive land consolidation schemes the stated objective of which was to “do away with the past”. However, in sp...

En Basse-Normandie, la « modernisation agricole » engagée au tournant des années 1950 a induit une recomposition sans précédent des espaces et des paysages ruraux. L'irrégularité de la trame parcellaire a été corrigée par des remembrements successifs dont l'objectif affiché était de faire « table rase du passé ». Pourtant, malgré la diminution sens...

This paper presents an application of a cellular automaton-based run-off model (RUICELLS) to a series of small dry valleys in the Seine-Maritime department, northern France, to better assess their susceptibility to flash flood. These muddy floods shortly follow high rainfall (50–100 mm in less than 6 h) and occur in very small areas (<20 km2). A su...

Quantification and characterization of hydrological and sedimentary transfers are now major challenges to preserving European soils and water resources (Law on Water, Water Framework Directive). In northwestern France, stream water quality is currently reduced by suspended sediment. However, in these low-energy water systems, sediment origin and dy...

ABSTRACT. In West Africa, studies on fluvial systems dynamics are rare and mainly conducted at the small scale to highlight the role of the climatic changes as single driver. This study aims to analyse the recent fluvial system dynamics of the small catchment (4400km²) of the Yamé river (Pays Dogon, Mali). To characterize the current fluvial patter...

Quantification and characterisation of hydrological and sedimentary transfers are now major challenges to preserving European soils and water resources (Law on Water, Water Framework Directive, WFD). Indeed, the consequences associated with these transfers can be catastrophic for continental and aquatic ecosystems, biodiversity and population (floo...

Quantification and characterisation of hydrological and sedimentary transfers are now major challenges to preserving European soils and water resources (Law on Water, Water Framework Directive, WFD). Indeed, the consequences associated with these transfers can be catastrophic for continental and aquatic ecosystems, biodiversity and population (floo...

We describe the methods and the main results obtained in the framework of the climaster project with the aim of contributing to the debate on climate change in the Grand Ouest (western part) of France. Concerning the climate, past long term series make it possible to analyse current climate change. One degree of temperature is the mean increase ove...

We describe the methods and the main results obtained in the framework of the climaster project with the aim of contributing to the debate on climate change in the Grand Ouest (western part) of France. Concerning the climate, past long term series make it possible to analyse current climate change. One degree of temperature is the mean increase ove...

This paper aims to investigate a new way of calculating potential impacts of flash floods. Mapping surface flow concentrations, using a new metric based on a cellular automaton RuiCells, is shown to qualitative align with observed and known instances of damage caused by flash floods in 5 small ‘dry valleys’ located in northern France (Parisian Basi...

This chapter provides a conclusion and future perspectives for Modeling and Optimization of Air Traffic. One of the great advantages of mathematical optimization is that it allows researchers in the domain to discover a wide range of application fields due to the quasi-universality of optimization requirements associated with human activities. Shor...

6554 (GEOPHEN-LETG). Courriel : daniel.delahaye@unicaen.fr 6 – Université Paris-Diderot (Paris 7), CNRS-UMR 8586 (PRODIG). Courriel : fort@univ-paris-diderot.fr 7 – Université Vincennes-Saint-Denis (Paris 8), CNRS-UMR 8591 (LGP). Courriel : emmanuele.gautier@cnrs-bellevue.fr 8 – Université Louis-Lumière (Lyon 2), CNRS-UMR 5600 (EVS). Courriel : Nic...

Co-Guest Editors would like to thank the authors who answered this call for papers and the eighteen anonymous reviewers. We also want to deeply thank Gilles Arnaud-Fassetta, Editor in Chief of the journal Géomorphologie: relief, processus, environnement for his confidence and his availability. Since a few decades hydro-geomorphologists use quantita...

This paper focuses on the spatial coexistence between different hazards (strong west winds, beach sedimentary crisis and flash floods) in outlets of small catchments in a sedimentary basin. This study was carried out in the department of Upper Normandy located in north-western France. To anticipate possible future hazards and damages without depend...

En Basse-Normandie, comme dans une grande partie des espaces ruraux européens, les transformations des systèmes de production agricole entamées au cours des années 1960 ont radicalement modifié les paysages et les rapports entretenus par les individus avec ces derniers. Cette contribution propose une étude des représentations paysagères des agricul...

Cet ouvrage donne pour la première fois une vue globale de la connaissance accumulée sur le changement climatique dans le Grand Ouest. Près de 80 spécialistes se sont mobilisés pour aborder ce champ très large d’interrogations : quelles sont les évolutions à venir dans une région où les modèles climatiques affichent la plus grande incertitude en pa...

Nous nous proposons dans cette communication de décrire la démarche et les principaux résultats qui ont été obtenus dans le cadre du projet CLIMASTER, pour contribuer au débat sur l’état actuel des connaissances sur le changement climatique (CC) dans le Grand Ouest. Vis-à-vis du climat, nous avons développé des analyses originales portant essentiel...

Cotton countryside in the Western Burkina Faso has rapidly evolved over the last fifty years. Agrarian and demographic transition has led to an important decline in bush areas. A phase of photo interpretation was conducted on a spatial extent comprising a dozen villages along the protected area of the Tui. After a description of spatial patterns wi...

Communication orale, Séminaire de clôture du programme interrégional PSDR GO, Climaster

Article de revue (Article scientifique dans une revue à comité de lecture)

Cellular Automata (CA) and Agent-Based Models (ABM) are used to better assess patterns and processes result-ing from environmental interactions using simple rules. Over the last ten years, the applications have been carriedout on various complex systems: flash floods, fire propagation, river meandering, landscape evolution... The fre-quent use thes...

Radio Phénix – Emission « L’ascenseur », 1ère diffusion le 19 mars 2011

Coordination : Olivier Planchon (COSTEL-LETG) ; 126 pages

These study analyze the role of protected areas on landscape evolution in western Burkina Faso. The analysis focuses on material change in landscape but also on representations due to those new protected areas. From aerial photography and investigations we try to understand how this area is observed by farmers. Different practices and perceptions o...

The cartography of erosion risk is mainly based on the development of models, which evaluate in a qualitative and quantitative manner the physical reproduction of the erosion processes (CORINE, EHU, INRA). These models are mainly semi-quantitative but can be physically based and spatially distributed (the Pan-European Soil Erosion Risk Assessment,...

Geomorphological and paleoenvironmental researches on Holocene sedimentation in the valleys of Normandy provide evidence for fluvial system changes related to climate and human activities in the Paris basin. Alluvial and colluvial deposits are important as archives of past environments changes. They can be used to construct the temporal frameworks...

The aim of this article is to review the current knowledge on flash floods occurring at the end of the spring or during the summer on the loamy plateaus of the Parisian Basin, in northwestern France. Classically named “muddy floods”, such hydrological hazards are significant as they cause losses of life and significant damage on buildings and infra...

Spatial organization of bush fires. Comparative approach in Burkina Faso Gestion des espaces Les feux de brousse en Afrique sub-saharienne sont le plus souvent considérés comme des aléas néfastes pour l'environnement. Pourtant il est maintenant avéré qu'ils participent, dans ces espaces tropicaux, à la structuration de la végétation des savanes. L...

The aim of this article is to review the current knowledge on flash floods occurring at the end of the spring or during the summer on the loamy plateaus of the Parisian Basin, in northwestern France. Classically named 'muddy floods', such hydrological hazards are significant as they cause losses of life and significant damage on buildings and infra...

The aim of this study is to propose preventive maps to provide better information on the flash floods occurring on the loamy plains of northern France (Paris Basin). Classically-named muddy floods in such areas, these events are significant as they cause important damage on buildings and infrastructures and can cause loss of life. Few studies have...

This paper focuses on the contribution of fluvial geomorphology to flood management. We define what fluvial geomorphologists understand by “fluvial risk” and examine the relationship between fluvial geomorphology and fluvial hazards. The paper details how fluvial geomorphology can present innovative approaches to flood prevention, river maintainanc...

In the areas with a dairy production and in a hedgerow landscape surrounding, the farms appearas the elementary units of the structuration of rural spaces and landscape. The study of the logics of organization of the farmers' practices thus appears as a pertinent grid to analyse the dynamics of the transformations of agricultural spaces and landsca...

In the areas with a dairy production and in a hedgerow landscape surrounding, the farms appear as the elementary units of the structuration of rural spaces and landscape. The study of the logics of organization of the farmers’ practices thus appears as a pertinent grid to analyse the dynamics of the transformations of agricultural spaces and landsc...

In bocage watersheds, the relationships between runoff producting areas and suspended sediments measurements are generally more difficult to assess than in openfield areas. Land use organisation and connectivity are the major controlling factors because man-made linear structures like hedges, roads or ditches networks strongly impact runoff pathway...

Cellular-based methods arising from the field of complex systems form a new paradigm for hydrology. These geosimulations, used more and more frequently, are supported by an array of advances both in hydrological sciences and in fields outside of geography. One of the most intriguing aspects of these models is the opportunity they provide for better...

Résumé Dans les régions laitières et bocagères d’Europe de l’ouest, fortement marquées par la présence de l’agriculture, l’organisation spatiale des activités agricoles apparaît comme centrale dans la structuration des paysages ruraux. L’analyse des facteurs de localisation des usages agricoles dans l’espace constitue une étape essentielle pour la...

Some “flash floods” with high suspended content affect at the end of spring and during the summer some parts of the Paris Basin, in north-western France, causing dramatic human and property damage: 269 events have been induced by 79 high rains between 1983 and 2005. Such events are the most dangerous form of floods encountered in this area because...

This paper focuses on the contribution of fluvial geomorphology to flood management. We define what fluvial geomorphologists understand by ‘fluvial risk’ and examine the relationship between fluvial geomorphology and fluvial hazards. The paper details how fluvial geomorphology can present innovative approaches to flood prevention, river maintainanc...

The beaches of Haute-Normandie, of which Quiberville and Pourville are the subject of this study, are characterised by W an accumulation of coarse sediment with it steep slope (10%) and, at the foot of this incline, a sandy foreshore with a low slope (1%) that is more dissipative, (2) a macrotidal environment and (3) a seawall, which stops them fro...

Classical morphometric indexes have been the first quantitative methods created by geomorphologists to compare the morphometric characteristics of many catchments and to quantify their theoretical hydrologic behaviour. Even if many indices still remain quoted in numerous hydrologic books, a few authors have recently underlined the drawbacks of such...

Agricultural statistics could be an interesting way to work about the spatial structures produced by agriculture on regional scale, in this case Normandy. The agricultural census gives a choice of a large panel of data which allow approaching the agricultural land patterns (main crops, permanent grass, etc.) and the economic configurations of the p...

In Basse-Normandie, soil erosion by water has weakened for more than 30 years the fertility of the cultivated soils and the quality of the water resource. The fight against erosion is registered as a priority in the policies of regional management which seek tools for diagnosis of fine scale on soil erosion risk. Tested for the Calvados (5500 km²),...

The soil erosion represents an important risk for agricultural lands and the areas located at the downstream: losses of soils, mud flows, turbidity and water pollution. In France, the intensive agricultural areas on silty soil appear among most sensitive to the soil erosion because of the evolution of the farming systems and the agricultural practi...