Philippe Chauvelon

The Vaccarès Lagoon System, located in the central part of the Rhône Delta (France), is a complex shallow coastal lagoon, exposed to a typical Mediterranean climate and a specific hydrological regime affected by man-controlled exchanges with the sea and agricultural drainage channels. In this article, we report the results obtained by a series of m...

Evapotranspiration (ET) can be mapped using thermal infrared and spectral reflectance data. Various ET models have been developed but there was no competitive evaluation of them over a large range of situations. Ensemble model averaging is a tool that can be used for deriving ET from multi-model simulations. In this study, we used bayesian model av...

Alternative agricultural systems, such as organic farming (OF), are promising options to sustain both agriculture productivity and environmental health. However, the adoption of OF by farmers is occurring more slowly than is advocated. A key factor limiting farmers is an inability to predict socio-economic consequences of converting to OF. To overc...

The spatiotemporal structure of wind-driven circulation patterns and associated water exchanges can drive important bio-hydrodynamic interactions in shallow lagoons. The Vaccarès lagoon system is a complex shallow hydrosystem located in the central part of the Rhône Delta (France). It is internationally recognized as part of a biosphere reserve wit...

The spatiotemporal structure of wind-driven circulation patterns and associated water exchanges can drive important bio-hydrodynamic interactions in shallow lagoons. The Vaccarès lagoon system is a complex shallow hydrosystem located in the central part of the Rhône Delta (France). It is internationally recognized as part of a biosphere reserve wit...

Is the regional conversion to Organic Farming (OF) possible? What could be the consequences at different scales in terms of social and economic development as well as nature conservation? Taking the heterogeneity of farms and farming systems in the region into account, are there farmers more prone to conversion and others that face greater obstacle...

Evapotranspiration (ET) is a fundamental variable of the hydrological cycle and its estimation is required for irrigation management, water resources planning and environmental studies. Remote sensing provides spatially distributed cost-effective information for ET maps production at regional scale. We have developed EVASPA tool for mapping ET from...

Oral presentation (EGU Vienna)

The "Ile de Camargue" is a complex hydrosystem, including agricultural drainage basins, marshes, and the brackish shallow Vaccarès lagoon system. This hydrosystem is particularly affected by water management and its endykement from the river and the sea. Decrease of sediment river input to the coast and sea level rise contribute to a global erosion...

The "Ile de Camargue" is a complex hydrosystem, including agricultural drainage basins, marshes, and the brackish shallow Vaccarès lagoon system. This hydrosystem is particularly affected by water management and its endykement from the river and the sea. Decrease of sediment river input to the coast and sea level rise contribute to a global erosion...

The purpose of this work was to develop a coupled hydrological and chemical model that can simulate time-dependent concentrations of pesticides and their degradation products in shallow coastal water bodies of variable volumes. The model was applied to simulate the exposure of two herbicides, oxadiazon and MCPA, in three interconnected lagoons whic...

We show limits and potential applications of satellite images linked with agricultural and natural habitats and flooded duration problematic. Satellite images could play a major role in the study and monitoring context. When we started our satellite images collection in 1975, it allowed us to map annual variations of habitats and flooded areas. Sin...

Although the colonisation of coastal rivers on the Atlantic and Mediterranean coast by glass eels, Anguilla anguilla, has been well studied and understood, the colonisation of lagoons by glass eels is much less known. For the first time in the Mediterranean region, the installation of a glass eel fish-pass in Grau de la Fourcade channels in the Rhô...

A field study on the runoff of pesticides was conducted during the cultivation period in 2004 on a hydraulically isolated rice farm of 120 ha surface with one central water outlet. Four pesticides were studied: Alphamethrin, MCPA, Oxadiazon, and Pretilachlor. Alphamethrin concentrations in runoff never exceeded 0.001 microg L(-1). The three other p...

Although the colonisation of coastal riv-ers on the Atlantic and Mediterranean coast by glass eels, Anguilla anguilla, has been well studied and understood, the colonisation of lagoons by glass eels is much less known. For the first time in the Mediterranean region, the installation of a glass eel fish-pass in Grau de la Fourcade channels in the Rh...

The multidisciplinary research project "GIZCAM" began in January 2006 and will last 3 years, coordinating several research axes in order to promote Integrated Coastal Zone Management. It is scheduled to finalize a simulation model of the "Ile de Camargue" (Rhone Delta central area) hydrological functioning; to make it more modular in order to integ...

This paper aims to define if natural conditions (wind rose and beach morphology) are favorable to dune formation on Camargue beaches under erosion. First, aeolian transport has been measured with sediment traps at the beginning and at the peak of a storm. When the storm starts the beach is not yet flooded and the berm provides sand to the dune. The...

The fish and macro-crustacean community of the Vaccarès lagoon (Rhône River delta, South France) was sampled monthly from 1993 to 2002. The lagoon salinity shifted from 15 in 1993 to 5 in 1994–1997 and went back to 15 in 1999–2002. Connections with the sea also varied during the study period with larger openings in 1996–1997. During the study perio...

In autumn and winter 1993-94, two major floods of the Rhone river caused dyke breaching in the delta. Water from inundated area was mainly transfered to the Vaccares lagoon, and from the lagoon to the sea, either by gravity or pumping. As a consequence, great quantities of supended matter entered the hydrosystem, and the flushing of the lagoons cau...

This paper presents a model of a heavily managed coastal Mediterranean wetland. The hydrosystem studied , called ``Ile de Camargue", is the central part of the Rhone river delta. It comprises flat agricultural drainage basins, marshes, and shallow brackish lagoons whose connection to the sea is managed. This hydrosystem is subject to strong natural...

We present a methodology using satellite images for the inventory and monitoring of temporarily flooded areas during the year. Radar images (ERS SAR C band) were used for this purpose. To calibrate and validate our images, a precise Digital Elevation Model (DEM) was made of the pilot site. The DEM, integrated in a Geographical Information System (G...

Restoration of wetlands has become an increasing field of application of ecological research due to mitigation regulations, changes in agricultural practices and an increasing consideration of the role of wetlands in the water cycle. In areas where the history of human use of natural areas is old and intense, restoration projects must not only cons...

The Isle of Camargue, central part of the Rhone delta, is a highly anthropized complex hydrosystem, combining agricultural drainage basins, marshes, and shallow brackish lagoons whose connection to the sea is managed. This system is submitted to a strong natural hydrological variability due to mediterranean climate and to an artificial hy- drologic...

A severe freshwater inflow during our long-term ichthyological study of the brackish Vaccars lagoon (1993–1998) helped us to assess the impact of sudden environmental changes on the specific biomass composition of the gobiid population and the catches per unit effort of the black goby Gobius niger, the common goby Pomatoschistus microps and the san...

In the Rhône River delta (France), flooded rice cropping requires constant irrigation from April to September. Irrigation volumes used are highly variable, and depend greatly on specific cropping practices. Land use characteristics were digitized, updated with classified satellite images, and placed in a GIS format. The actual irrigation volumes we...

In the Rhône River delta (France), flooded rice cropping requires constant irrigation from April to September. Irrigation volumes used are highly variable, and depend greatly on specific cropping practices. Land use characteristics were digitized, updated with classified satellite images, and placed in a GIS format. The actual irrigation volumes we...

Irrigation pumps are the main aquatic connexions between the Isle of Camargue and any other freshwater system. Fish passage was monitored in 2 sites among the 15 pumping stations of the Fumemorte catchment (68 km2) during an entire rice cultivation period, from April to October 1997.

Les pompes d'irrigation constituent la principale connexion aquatique entre l'île de Camargue et d'autres milieux d'eau douce. Nous avons suivi le passage de poissons dans 2 sites parmi les 15 stations de pompage du bassin du Fumemorte (68 km2) pendant toute la période rizicole, c'est-à-dire de fin avril à début octobre 1997. Les poissons peuvent s...

Wetlands are often extremely dynamic areas, as well at hydrological level as for the sedimentary transport. Trough the study of a pond system in the Camargue, we propose to set up a follow-up methodology of these «unforeseable» environments. The methodology relies on ground based measurements and on satellite imagery. All collected data are integra...

With the development of rice cultivation in the 50's, a great part of the Isle of Camargue, the central area of the Rhône river delta, was polderized. The Vaccarès lagoon system (110 km2, 65 km2 for the Vaccarès lagoon itself) represents the main part of the 'Réserve Nationale de Camargue'. Without human intervention, it is hydraulically isolated f...

Back-calculation formulae (BCF) frequently used for deriving fish growth can only be applied when considering a predefined reference axis to measure growth rings and daily growth increments on otoliths. Many otoliths are difficult to interpret and it is often not possible to age fish along the predefined axis. A back-calculation model which avoids...

Les formules classiques de rétrocalcul ne sont applicables que dans le cas de mesures d'annuli réalisées selon un axe standard de lecture. La modélisation du plan de la coupe transversale d'un otolithe par une ellipse permet de s'affranchir de cette contrainte. Considérant les coordonnées polaires d'un point sur un annuli et la taille correspondant...

Un dispositif semi-automatique de comptage des microstries de l'otolithe est présenté. Un système d'analyse d'image permet l'acquisition de l'information sous forme numérique. La modélisation de celle ci au moyen d'une méthode d'analyse des séries chronologiques contribue à l'estimation du nombre de périodes (microstries) contenues dans le signal....

Les systèmes d'analyse d'image permettent le stockage, la manipulation numérique d'images, et leur utilisation en sclérochronologie est en plein essor. Le logiciel présenté dans ce travail, développé sur micro-ordinateur, permet l'acquisition semi-automatique des données relatives à l'âge, résultant de l'observation des pièces dures. (Résumé d'aute...

La présente étude porte sur la détermination otolithométrique de l'âge d'un poisson exploité sur le plateau des Seychelles, #Lutjanus sebae$ (Cuvier, 1828). Les observations ont été effectuées sur des coupes transversales d'otolithes sagitta incluses à l'aide d'un dispositif d'analyse d'image. En raison des particularités du matériel biologique étu...

This work was part of the IMPLIT project ("Impact of extreme events (storms and sea surges) linked to climatic change, on the French coastal Mediterranean hydro-systems") developed within the framework of the GICC program ("Management and impact of climatic change"), (Ministry of Ecology and Sustainable Development). The objective of the Rhone delt...

In the western part of the Mediterranean basin, the Rhone delta is probably one of the most complex coastal hydrosystem, displaying very strong inter-relationships between human activities and ecosystem evolution. The Camargue has a made up complex hydrosystem of sub-horizontal drainage basin managed for an agriculture strongly dominated by rice cu...