Incidences de la notion de cours d’eau sur la gestion et la pérennité des étangs. Le cas de la dérivation

En France, la conception des cours d’eau est qualitative et environnementale et leur réglementation très forte. La gestion des étangs sur cours d’eau est fortement dépendante de cette même réglementation. Pour favoriser l'atteinte du bon état écologique des cours d'eau, l'aménagement de plus en plus promu est le système de dérivation dont le but est de réduire les méfaits réels et/ou supposés de ces plans d'eau. Mais l’absence de définition des cours d’eau et la grande méconnaissance de l’impact de la dérivation, plus encore selon les différents types d’étangs, peuvent engendrer une gestion inadaptée des étangs et/ou mettre en jeu leur pérennité. Il est donc nécessaire d’éclairer la notion de cours d’eau par une réflexion sur la réglementation et la gestion induite par celle-ci ainsi que d'éclairer l’utilité de la dérivation au moyen d'apports scientifiques.In France, apprehension of watercourse is qualitative and environmental and his regulation is powerful. Management ponds on watercourse is highly dependent of the same regulation. More and more promoted, diversion is supposed to reduce ponds damages, to achieve good environmental status. But the lack of definition of watercourse and widespread ignorance of the impact of the diversion, even for different types of ponds can lead to an inadequate management of ponds and / or jeopardize their sustainability. Therefore, it is necessary to clarify the concept of watercourse with a reflection on the regulation and management induced by it as well as the usefulness of the bypass scientific contributions.In Frankreich ist die Wasserwirtschaft qualitativ und ökologisch ausgerichtet und einer starken Regulierung unterworfen. Die Bewirtschaftung von Teichen, die sich auf Wasserstraßen befinden, basiert auf letzteren Vorschriften. Zur Erreichung eines guten ökologischen Zustandes der Gewässer wird immer mehr das Bypass-System gefördert mit dem Ziel, die möglichen und / oder reellen negativen Folgen dieser Wasserflächen zu reduzieren. Die fehlende Definition der Fließgewässer und die große Unkenntnis über die Auswirkungen der Umleitung, inklusivehinsichtlich verschiedenerTeicharten, können ein schlechtes Management der Teiche verursachen und ihre Nachhaltigkeit gefährden. Hieraus ergibt sich die Notwendigkeit, das Konzept der Fließgewässer anhand einer Analyse der Regulierung und der daraus resultierenden Bewirtschaftung, näher zu beleuchten und die Nützlichkeit des Bypass-Systems wissenschaftlich zu überprüfen

European perspectives on regional estimates of standing water bodies and the relevance of man-made ponds

International audienceThe majority of terrestrial standing water bodies (SWB) are small in size, however, their abundance and distribution is not fully known and they are under-represented in legislation. Also, the models for global inventories of SWB are so far not sufficiently designed for estimating the relative abundance of small SWB (below 0.2 ha) and provide differing estimates. In this pilot study, we suggest a bottom-up approach for estimating the number of SWB at EU-level that combines the ground-validated data on water bodies from state inventories and data from peer-generated map databases; we assess the inventories and relative importance of small terrestrial water bodies of two different countries, Estonia and France

Field Effectiveness of Pandemic and 2009-2010 Seasonal Vaccines against 2009-2010 A(H1N1) Influenza: Estimations from Surveillance Data in France

BACKGROUND: In this study, we assess how effective pandemic and trivalent 2009-2010 seasonal vaccines were in preventing influenza-like illness (ILI) during the 2009 A(H1N1) pandemic in France. We also compare vaccine effectiveness against ILI versus laboratory-confirmed pandemic A(H1N1) influenza, and assess the possible bias caused by using non-specific endpoints and observational data. METHODOLOGY AND PRINCIPAL FINDINGS: We estimated vaccine effectiveness by using the following formula: VE  =  (PPV-PCV)/(PPV(1-PCV)) × 100%, where PPV is the proportion vaccinated in the population and PCV the proportion of vaccinated influenza cases. People were considered vaccinated three weeks after receiving a dose of vaccine. ILI and pandemic A(H1N1) laboratory-confirmed cases were obtained from two surveillance networks of general practitioners. During the epidemic, 99.7% of influenza isolates were pandemic A(H1N1). Pandemic and seasonal vaccine uptakes in the population were obtained from the National Health Insurance database and by telephonic surveys, respectively. Effectiveness estimates were adjusted by age and week. The presence of residual biases was explored by calculating vaccine effectiveness after the influenza period. The effectiveness of pandemic vaccines in preventing ILI was 52% (95% confidence interval: 30-69) during the pandemic and 33% (4-55) after. It was 86% (56-98) against confirmed influenza. The effectiveness of seasonal vaccines against ILI was 61% (56-66) during the pandemic and 19% (-10-41) after. It was 60% (41-74) against confirmed influenza. CONCLUSIONS: The effectiveness of pandemic vaccines in preventing confirmed pandemic A(H1N1) influenza on the field was high, consistently with published findings. It was significantly lower against ILI. This is unsurprising since not all ILI cases are caused by influenza. Trivalent 2009-2010 seasonal vaccines had a statistically significant effectiveness in preventing ILI and confirmed pandemic influenza, but were not better in preventing confirmed pandemic influenza than in preventing ILI. This lack of difference might be indicative of selection bias

La fécondation in vitro : une technique pour palier à l'infertilité des couples en France

REIMS-BU Santé (514542104) / SudocSudocFranceF

Ponds: conservation through a better management of environmental impacts. Diversion: an optimal management?

International audienceFrench ponds suffer from bad press regarding their environmental impact. In the context of aquatic environments protection, their survival is in jeopardy. Their management in order to reduce the hazard seems the only way to ensure their maintenance. To achieve this, water managers advocate the diversion described as the best way. But no scientific study corroborates their statements. That is why we propose a thermal study in the long-term of three ponds in the Loire headwater catchment. Indeed, temperature is a key parameter in water quality and a remarkable indicator. Given the results from more than 51,000 unpublished data, we argue that in this time scale, regardless of types of diversion ponds, this management can reduce or even remove the thermal impact ponds

Ponds: conservation through a better management of environmental impacts. Diversion: an optimal management?

International audienceFrench ponds suffer from bad press regarding their environmental impact. In the context of aquatic environments protection, their survival is in jeopardy. Their management in order to reduce the hazard seems the only way to ensure their maintenance. To achieve this, water managers advocate the diversion described as the best way. But no scientific study corroborates their statements. That is why we propose a thermal study in the long-term of three ponds in the Loire headwater catchment. Indeed, temperature is a key parameter in water quality and a remarkable indicator. Given the results from more than 51,000 unpublished data, we argue that in this time scale, regardless of types of diversion ponds, this management can reduce or even remove the thermal impact ponds

Les risques d’érosion sur les rives des étangs, le cas du démaigrissement des plages

International audiencePonds shore management and beach erosion risk. Ponds are very small water bodies where shore erosion mainly depends on wind waves. In Central-Western France (departments of Indre, Vienne, Haute-Vienne and Creuse) some fifty ponds present artificial beaches for tourism. Maps of effective lengths and fetches allow to estimate the beach erosion hazard. The example of the Rochegaudon pond (municipality of Chaillac), which is an oblong pond from north to south with a crescent form, shows that the theoretical maximum erosion (effective length calculation) occurs in the extremities and on the convex shore. The compass card of the meteorological station adds some information aboutsouth-western dominant winds. We suggest new morphoclimatic indicators such as asymmetric effective fetch and coefficiented fetch, whose computing and mapping show a maximum shore erosion in the north-east of the pond. This part of the shore just coincides with the beach of Rochegaudon, which took place on ancient micro-cliffs buried under a big artificial input of granitic sand. The choice of the beach location previously depended of criteria such as the nearness of the camping site, the road and the car park. At the present time the municipality manages the beach erosion by supplying every year the beach with sand

Les risques d’érosion sur les rives des étangs, le cas du démaigrissement des plages

International audiencePonds shore management and beach erosion risk. Ponds are very small water bodies where shore erosion mainly depends on wind waves. In Central-Western France (departments of Indre, Vienne, Haute-Vienne and Creuse) some fifty ponds present artificial beaches for tourism. Maps of effective lengths and fetches allow to estimate the beach erosion hazard. The example of the Rochegaudon pond (municipality of Chaillac), which is an oblong pond from north to south with a crescent form, shows that the theoretical maximum erosion (effective length calculation) occurs in the extremities and on the convex shore. The compass card of the meteorological station adds some information aboutsouth-western dominant winds. We suggest new morphoclimatic indicators such as asymmetric effective fetch and coefficiented fetch, whose computing and mapping show a maximum shore erosion in the north-east of the pond. This part of the shore just coincides with the beach of Rochegaudon, which took place on ancient micro-cliffs buried under a big artificial input of granitic sand. The choice of the beach location previously depended of criteria such as the nearness of the camping site, the road and the car park. At the present time the municipality manages the beach erosion by supplying every year the beach with sand

The stability of the water column in French ponds (Limousin region) by the calculation of the Wedderburn number

Conference dedicated to the World Meterological Day and the World Water DayInternational audienceOxygenation and biological life in lakes, reservoirs and ponds depend on the stability of the water column and on the rhythms of stratification and mixing periods. Slight thermal stratification in ponds often is regarded as the same as instability in shallow lakes. Nevertheless fetch in ponds is very short, what reduces the mixing. Wedderburn number (quotient of the buoyancy by the mixing) is used to quantify the stability in shallow water bodies. We calculate it for some ponds in French region Limousin, due to original hourly water temperature measurements in all depths and wind data of Météofrance stations. First results show that very high values (above 10) are frequent in summer and spring period (during 41% of the total time of 2 336 hours from May to July in three ponds). That is why we may consider Limousin ponds as stable stratified bodies of water despite their shallowness. Continuous measurements allow to calculate the diurnal cycle and other time scales of the Wedderburn number, with periods of weakening, when air temperatures and surface water temperatures decrease, wind speed increases and when the wind blows in the same direction with the length of the pond. The most complex variable is the depth of the thermocline; a light increase of the breeze thickens the upper warm layer and strengthens the stability, but an important increase of the wind tends to destroy the stratification

La stabilité de la colonne d’eau des étangs français (région Limousin) par le calcul du Nombre de Wedderburn

Conference dedicated to the World Meterological Day and the World Water DayInternational audienceOxygenation and biological life in lakes, reservoirs and ponds depend on the stability of the water column and on the rhythms of stratification and mixing periods. Slight thermal stratification in ponds often is regarded as the same as instability in shallow lakes. Nevertheless fetch in ponds is very short, what reduces the mixing. Wedderburn number (quotient of the buoyancy by the mixing) is used to quantify the stability in shallow water bodies. We calculate it for some ponds in French region Limousin, due to original hourly water temperature measurements in all depths and wind data of Météofrance stations. First results show that very high values (above 10) are frequent in summer and spring period (during 41% of the total time of 2 336 hours from May to July in three ponds). That is why we may consider Limousin ponds as stable stratified bodies of water despite their shallowness. Continuous measurements allow to calculate the diurnal cycle and other time scales of the Wedderburn number, with periods of weakening, when air temperatures and surface water temperatures decrease, wind speed increases and when the wind blows in the same direction with the length of the pond. The most complex variable is the depth of the thermocline; a light increase of the breeze thickens the upper warm layer and strengthens the stability, but an important increase of the wind tends to destroy the stratification.L’oxygénation et la vie biologique des lacs naturels, des lacs de barrage et des étangs dépendent des caractéristiques de stabilité de la colonne d’eau, c’est-à-dire des rythmes faisant alterner les périodes de stratification et de mélange. La fragile stratification thermique des étangs est souvent considérée dans la littérature scientifique comme équivalente à l’instabilité des lacs peu profonds. Néanmoins, le fetch (course du vent) sur les étangs est très court, ce qui réduit les possibilités de brassage. Le Nombre de Wedderburn (quotient de la flottabilité par la possibilité de brassage) est employé pour quantifier la stabilité dans les plans d’eau pelliculaires. Nous l’avons calculé dans plusieurs étangs limousins, à partir de nos mesures inédites de température horaire de l’eau à toutes les profondeurs et des données de vent des stations Météofrance. Les premiers résultats montrent que des valeurs très élevées (supérieures à 10) sont fréquentes en période estivale et au printemps (pendant 41% du temps total de 2 336 heures allant de mai à juillet dans les trois grands étangs de la Pouge, de Cieux et des Oussines). Ainsi, malgré leur faible profondeur absolue, on peut considérer que, en saison chaude, les étangs limousins se conduisent comme des plans d’eau stratifiés stables. Les mesures en continu permettent aussi de calculer le Nombre de Wedderburn à l’échelle du cycle diurne. En général le Nombre baisse, quand les températures de l’air et des eaux de surface diminuent, la vitesse du vent augmente et le vent souffle dans le même sens que la longueur de l’étang. La profondeur de la thermocline forme une variable complexe : une légère augmentation de la brise épaissit la couche chaude supérieure et renforce la stabilité, mais une augmentation importante du vent tend à détruire la stratification