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First meetings between FODs
From 26 to 29 April 2011, Onema organised the first annual symposium of the overseas departments. The meeting brought together, in Vincennes, the "water and aquatic environment" section heads of the departmental environmental agencies or the Water offices of Guadeloupe, Martinique, Guiana, Reunion and Mayotte. The goal was to identify R&D needs, jointly define and set priorities for the corresponding work and to discuss overseas aspects of the national framework for water data. The work will address the status of surface and groundwater, hydromorphology, chemical monitoring, ecotoxicology, the development of bioindicators, etc.


Contact: olivier.monnier@onema.fr

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Chlordecone - step two with the 2011-2013 national plan
Chlordecone is a pesticide that was widely used in the Caribbean to destroy banana root borers, before being banned in 1993. Given the health, environmental, social and economic issues raised by the persistent contamination of environments in Guadeloupe and Martinique, the national action plan was revived. Studies co-funded by Onema revealed that the substance has contaminated all environments, from the river basins where the product was used to marine waters, via transfer mechanisms that require further research. The goal of the second plan for 2011-2013 is to shift from monitoring to operational management of efforts to counter the impacts of the pollutant. The priority is to find a means to degrade the substance or at least reduce its impact. Better knowledge on transfer mechanisms from plants to soil and from soil to water should help in rapidly setting up corrective measures for the contamination. The project as a whole is part of an overall effort to share knowledge and research projects between the two Caribbean islands.


Contact: nicolas.domange@onema.fr

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Green technologies and treatment of effluents
Depending on the FOD, between 20 and 40% of the population has access to collective sanitation systems. With Cemagref, Onema funds experiments intended to optimise certain treatment techniques. The goal of the first project, dealing with the design of planted drying beds used to treat sludge and sewage from non-collective sanitation systems, is to adapt the technique to the tropical context. Initial results stress the need to respect certain key aspects to ensure system longevity, namely the start-up phase to allow plants to develop correctly, a sufficient number of drying beds with alternating supply, etc. A guide containing recommendations on system sizing will be published in 2012. A second project addresses the design and management of wastewater-treatment systems using planted filters and intended for small to mid-sized local governments. Two pilot sites have been designated, one in Martinique and the other in Guadeloupe.


Contact: stephane.garnaud@onema.fr

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Monitoring aquifers in the Caribbean
What is the impact of rising sea levels on aquifers? What is the risk of saltwater reaching groundwater and impacting the quality of water resources? These questions are vitally important in the overseas territories where the rise in sea levels caused by climate change (approximately one metre according to the latest estimates) combines with surges in water levels caused by tropical storms. Onema has funded a study by BRGM. In Reunion, Guadeloupe and Martinique, researchers collected data on aquifer characteristics, their salinity and coastal topography. Using the data, they then mapped the risks of aquifers being affected by saltwater due to an increase in sea levels. The researchers will subsequently model the situation for Reunion and Guadeloupe and the results on the exposure of aquifers will make it possible to address the most vulnerable.


Contact: pascal.maugis@onema.fr

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Selecting bioindicators for coral reefs

How can the ecological status of coral reefs, a feature specific to the tropical islands of the overseas territories, be evaluated? To determine the best bioindicators for these environments, a special work group was set up at the beginning of 2011. The group, managed by Onema and the National museum of natural history, comprises experts from IRD in Nouméa and other research institutes. Its mission is to assess the relevance of biological-quality factors currently being studied and to propose new ideas. Candidates for high-performance indicators on the impact of human activities on reef waters are macroalgae, for situations involving eutrophication, and certain groups of benthic invertebrates, for problems of hypersedimentation.


Contact: olivier.monnier@onema.fr

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A database on river obstacles
The inventory of obstacles to river flow, managed by Onema and designed to comply with WFD requirements, is now being set up for the FODs. The updated and consolidated data on obstacles are transmitted by the local entities, i.e. the departmental environmental agencies and the Water offices. The data will then be mapped using a version of the Géobs tool adapted to the overseas territories. Due to the difficulty of accessing certain obstacles, more work will be required to complete the inventory in Guiana. The database will serve to set work priorities in view of re-establishing ecological continuity.


Contact: jean-marc.baudoin@onema.fr

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Measuring the passability of installations
Analysis of the passability of an installation, i.e. the capacity of fish to overcome the obstacle, is based on the ICE (information on ecological continuity) protocol that was created in continental France for species whose behaviour is now well known. The protocol comprises a database and a decision tree used to diagnose installation passability. It is now being tested in Reunion where continuity issues are different, notably in terms of the species and families involved, e.g. macrocrustaceans. The protocol also covers continuity for sediment. In the overseas territories, the flow rates of rivers combined with high precipitation results in significant particle flows. A scientific and technical guide on the general principles and methods involved in the protocol is now being drafted and should be published by the end of 2011.


Contact: jean-marc.baudoin@onema.fr

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A status report on migratory species
In setting up the national management strategy for migratory fish, Onema and the National museum of natural history will co-fund a complete inventory of migratory species in the FODs, with the exception of Guiana which will be studied later. To draw up the status report, the museum will collect all available data on populations, on pressures (fishing, installations, pollution) and on existing management systems in Guadeloupe, Martinique, Reunion and Mayotte. The results of the study will be used to harmonise management techniques for migratory fish between continental France and the FODs.


Contact: benedicte.valadou@onema.fr

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Test on the Carhyce protocol in Martinique
The Carhyce protocol, deployed in continental France in 2009, lists the measurements that must be made on rivers in view of restoring good hydromorphological quality. To adapt the protocol to the characteristics of the overseas territories, e.g. heavy particle flows and changes in river beds due to the tropical climate, it will be tested at the end of 2011 in Martinique in the stations of the surveillance-monitoring network. One result should be better monitoring of sediment transport. The data collected in the field will be entered into a database for analysis. A guide on protocol use in the FODs will be published at the end of 2012.

Contact: jean-marc.baudoin@onema.fr

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Carthage database now available in Guiana
Following two years of work, the Guiana river basins are now included in the Carthage hydrographic database. Thanks to the Guiana regional environmental agency and assistance from many partners (Cemagref, Defence ministry, private companies, IGN, Water office, IRD, etc.), the database now provides more in-depth information on the specific hydrographic characteristics of the Amazonian basin, notably its rivers, water bodies, obstacles, wetlands (marshes, mangroves, swamp forests, floodable savannas, rice paddies, coastal mud flats) and former gold-washing sites. Onema carried out the project under the management of the departmental environmental agency. The database will be freely accessible starting in the summer of 2011.

Contact: helene.augu@onema.fr

 

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