Hydro-socio-economic implications for water management strategies: the case of Roussillon coastal aquifer

In many Mediterranean coastal areas, agriculture, drinking water supply, tourism and industry strongly depend on the available groundwater resources. As a result of the significant economic development during the last three decades along the coast, abstractions from coastal aquifers have increased tremendously, frequently leading to overexploitation and saltwater intrusion. Geological, hydrogeological and socio-economical studies as a multidisciplinary approach on a coastal Mediterranean aquifer- the Roussillon - have been carried out in order to design effective water management strategies on areas sensitive to seawater intrusion risk. Geology provides geometry and architecture of the different aquifers, hydrogeology assess the seawater intrusion risk while socio-economic study includes consulting the stakeholders with the aim of suggesting water management and policy option acceptable to the majority of population. This paper then highlights the economic interests at stake, diversity of viewpoints expressed by stakeholders and political dimension of the issue, which are likely to be encountered for all similar situations on both sides of the Mediterranean Sea.GESTION DE L'EAU;STRATEGIE;HYDROGEOLOGIE;SOCIOLOGIE;ECONOMIE;MER MEDITERRANEE;ROUSSILLON

A pluridisciplinary methodology for intregrated management of coastal aquifer - Geological, hydrogeological and economic studies of the Roussillon aquifer (Pyrénées-Orientales, France)

In order to study Mediterranean coastal water management, a pluridisciplinarity approach is developed. Reservoir geology and some of its tools, used in oil prospecting, are applied to build a detailed sedimentary model. The analysis of depositional environments and sedimentary process allows the correlation of pre-existing data (outcrop, borehole, and seismic profile) using Genetic stratigraphy (onshore domain) and seismic stratigraphy (offshore domain). The interpretation results in a better knowledge of the sedimentary geometries following correlations between onshore and offshore domains. It is thus possible to differentiate the coastal groundwater aquifers precisely and to establish their relative connections. At the same time, hydrogeological investigations such as hydrochemistry and geophysical prospecting allow us to elaborate the hydrogeological conceptual model of the case studies. Variable-density flow and solute transport simulations constitute the hydrogeological work. Experimental economy constitutes the third part of this integrated methodology. It assesses the effectiveness of institutional arrangements to cope with aquifer overexploitation. Feed-back from these three fields of research will also authenticate our methodology. This approach applied on Roussillon basin (South-west of French Mediterranean coastline) could be exported to many other coastal area

Hydro-socio-economic implications for water management strategies: the case of Roussillon coastal aquifer

In many Mediterranean coastal areas, agriculture, drinking water supply, tourism and industry strongly depend on the available groundwater resources. As a result of the significant economic development during the last three decades along the coast, abstractions from coastal aquifers have increased tremendously, frequently leading to overexploitation and saltwater intrusion. Geological, hydrogeological and socio-economical studies as a multidisciplinary approach on a coastal Mediterranean aquifer- the Roussillon - have been carried out in order to design effective water management strategies on areas sensitive to seawater intrusion risk. Geology provides geometry and architecture of the different aquifers, hydrogeology assess the seawater intrusion risk while socio-economic study includes consulting the stakeholders with the aim of suggesting water management and policy option acceptable to the majority of population. This paper then highlights the economic interests at stake, diversity of viewpoints expressed by stakeholders and political dimension of the issue, which are likely to be encountered for all similar situations on both sides of the Mediterranean Sea

Electrical Conductivity Studies on Individual Conjugated Polymer Nanowires: Two-Probe and Four-Probe Results

<p>Abstract</p> <p>Two- and four-probe electrical measurements on individual conjugated polymer nanowires with different diameters ranging from 20 to 190 nm have been performed to study their conductivity and nanocontact resistance. The two-probe results reveal that all the measured polymer nanowires with different diameters are semiconducting. However, the four-probe results show that the measured polymer nanowires with diameters of 190, 95&#8211;100, 35&#8211;40 and 20&#8211;25 nm are lying in the insulating, critical, metallic and insulting regimes of metal&#8211;insulator transition, respectively. The 35&#8211;40 nm nanowire displays a metal&#8211;insulator transition at around 35 K. In addition, it was found that the nanocontact resistance is in the magnitude of 10⁴&#937; at room temperature, which is comparable to the intrinsic resistance of the nanowires. These results demonstrate that four-probe electrical measurement is necessary to explore the intrinsic electronic transport properties of isolated nanowires, especially in the case of metallic nanowires, because the metallic nature of the measured nanowires may be coved by the nanocontact resistance that cannot be excluded by a two-probe technique.</p

Characterizing floods in the poorly gauged wetlands of the Tana River Delta, Kenya, using a water balance model and satellite data

Wetlands, such as those of the Tana River Delta in Kenya, are vital but threatened ecosystems. The flooding characteristics of wetlands largely determine their physical, chemical and biological properties, so their quantification is crucial for wetland management. This quantification can be achieved through hydrological modelling. In addition, the analysis of satellite imagery provides essential hydrological data to monitor floods in poorly gauged zones. The objective of this study was to quantify the main water fluxes and flooding characteristics (extent, duration and number of floods) in the poorly gauged Tana River Delta in East Africa during 2002-2011. To do so, we constructed a lumped hydrological model (the Tana Inundation Model, TIM) that was calibrated and validated with MODIS data. Further analysis of the MYD09A1 500 m composite product provided a map of the empirical probability of flooded state. In non-extreme years and for the current topology of the delta, the flood extent exceeded 300 km(2). Floods over 200 km2 occurred on average once a year, with a mean duration of 18 days. River discharge from the upper basin counted for over 95% of the total water inflow. The results are discussed in the light of possible improvements of the models and wetland management issues. This study provides the first known quantification of spatial and temporal flooding characteristics in the Tana River Delta. As such, it is essential for the water and natural resource management of the Tana River basin. The water balance approach was pertinent to the study of this system, for which information on its internal properties and processes is limited. The methodology, a combination of hydrological modelling and flood mapping using MODIS products, should be applicable to other areas, including those for which data are scarce and cloud cover may be high, and where a medium spatial resolution is required

Importance of a high resolution lithological and geometrical knowledge for Mediterranean coast sedimentary aquifers management. Application to the Roussillon basin, South of France

International audienceA good understanding of coastal aquifers is particularly important for their management and preservation,as well as for specific implementations (artificial recharge). A detailed knowledge of the lithology andgeometry of the aquitards and aquicludes is as important as that of the aquifers, particularly for seawaterencroachment dynamics. A new methodology, based on reservoir geology, is used to contribute to highresolutionlithological and geometrical knowledge of coastal sedimentary aquifers. The proposedmethodology is being applied on the Roussillon Basin, located along the southernmost part of the FrenchMediterranean coast, near the Spanish border. This basin covers an area of 700 km2 and comprises twoPliocene aquifers whose characteristics are linked to the Messinian event, and is overlain by the Quaternaryaquifer whose geometry is linked to eustatic variations. All these aquifers consist of alluvial and coastaldeposits. A detailed lithology and geometry model of this basin has been made mainly on the basis ofreservoir geology methods: (i) on-shore, through genetic stratigraphy and (ii) off-shore, through seismicstratigraphy. A detailed mapping of the elevation of the top and base of the aquifers andaquitards/aquicludes is thus available and will be used in a hydrogeological finite difference model. Thismodel will be used for various applications such as aquifer management, location of the outflow areas ofthe aquifers and sensitivity analysis on geometry (on-shore-off-shore)

Transport and vibrational properties of poly(3,4-ethylenedioxythiophene) nanofibers

Nanofibers of poly(3,4-ethylenedioxythiophene) (PEDOT) have been electrochemically synthesized by the template method and their morphology determined using electron microscopy. A comparative resonant Raman scattering study has been performed on films, bundles of fibers and individual fibers of different diameters. Their temperature dependent transport properties have also been investigated and compared with the case of a PEDOT thin film. The PEDOT is found to be in an insulating state close to the metal-insulator transition. The temperature dependence of the fibers' conductance is larger than for the films, and this variation increases for a smaller fiber diameter. These results suggest that a confining effect on the PEDOT structure occurs during the electrochemical synthesis in the template. (C) 2002 Elsevier Science B.V. All rights reserved

Correlation between onshore and offshore Pliocene-Quaternary systems tracts below the Roussillon Basin (eastern Pyrenees, France)

International audienc