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What are sediments?

“A sedimentary deposit is that body of solid materials accumulated at or near the surface of the earth under the low temperatures and pressures which normally characterize this environment.  The sediment is generally, but not always, deposited from a fluid in which it was contained either in a state of suspension or solution.  This definition encompasses most of the materials considered sediments (or sedimentary rocks).” In Sedimentary Rocks, by F.J. PETTIJOHN.

“‘Fluvial sediments’ are those sediments that consist of material transported by, suspended in, or laid down by a stream (Bates & Jackson, 1980).  (…)  Millions of tons of sediments are transported annually to oceans, with amounts determined by climate, topography, vegetation cover, land-use, and the susceptibility of the underlying rocks, soils or other unconsolidated materials to physical, chemical and biological weathering.” In Environmental Sedimentology, by C. Perry & K. Taylor.

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River sediments and ecosystem functioning

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What is a drainage basin?

“A river system is, by definition, the system of connected river channels in a drainage (or catchment) basin (or watershed) (Bridge 2003).”  The drainage divide separates a drainage basin from others.  Water drains from the mountain belt, along alluvial channels, creating tributaries that flow into one main channel down to the sea.  In Environmental Sedimentology, by C. Perry & K. Taylor.

As a result, the limits of a watershed are independent from any administrative borders, and each small tributary possesses its own drainage basin.

Here, the drainage basins and main european drainage divides, and two views of the Loire basin. ……………………………………………………………………………………………………………………………………………………………………………………………..

The Sediments Observation Network of the Loire river basin

site under construction

The Réseau d’Observation des Sédiments de la Loire et de ses Affluents (Réseau O.S.L.A.) was established in 2011.  This project  was initiated by researchers of the Loire basin (with the support of the Zone Atelier Loire), in consultation with the main decision makers (DREAL Centre, Agence de l’Eau Loire-Bretagne, EPLoire, GIP Loire-Estuaire, Regions, EDF…). Similarly to the RSO (see further), the main goal of the Réseau OSLA is to improve scientific knowledge of the sedimentary processes in the Loire continental basin, in order to optimize its sustainable management (especially in terms of flood and pollution risks, but also to achieve good ecological state).  Thus, the Réseau OSLA brings together a community of multidisciplinary researchers in order to help managers in their decision making. INFO-Sed is developed and updated as one of its actions, with two main goals: sharing the existing data and knowledge, and communicating on the Réseau OSLA’s future results. …………………………………………………………………………………………………………………………………………………………………..

The Rhône Sediments Observatory

www.graie.org/osr/

The Rhône Sediment Observatory (RSO) is a research program established in 2009 in response to management questions that emerged as part of the “Plan Rhône” framework, regrouping different research teams situated along the length of the river (CNRS, IRSTEA, ENTPE, IRSN, IFREMER).  The RSO constitutes one of the observatories of the Zone Atelier du Bassin du Rhône (ZABR).  It benefits from the support of the European Regional Development Fund (ERDF). Two tools are available to browse through the data collected by the RSO: MetaOSR and GeoOSR.  Reference documents as well as activity reports are also available for download. …………………………………………………………………………………………………………………………………………………………………..

The European Sediment Network

www.sednet.org/

  SedNet is a European network aimed at incorporating sediment issues and knowledge into European strategies to support the achievement of a good environmental status and to develop new tools for sediment management.  It focuses on all sediment quality and quantity issues on a river basin scale, ranging from freshwater to estuarine and marine sediments.  SedNet brings together experts from science, administration and industry.  It interacts with the various networks in Europe that operate at a national or international level or that focus on specific fields (such as science, policy making, sediment management, industry, education).

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Project executors

The INFO-Sed tool was created through a collaboration between the GéHCO laboratory (University of Tours, France) and the Géo-Hyd consulting firm (based in Orléans, France).

The GéHCO laboratory (E.A. 6293), created on January 1st, 2012, specializes in the fields of Earth Sciences and Environment.  The Unit consists in 28 people: 13 researchers, 4 BIATOSS, 6 doctorates, 5 short-term positions.  The GéHCO is part of the CNRS FREDD 3097 research federation (Environmental risks and hazards from the watershed to the coast), which includes 19 laboratories of the Poitiers-Limoges-La Rochelle PRES. GéHCO’s research studies the impacts of climate change and human activities on fluvial systems, watersheds, and associated natural resources (water, soils, sediments).  The analyses are retrospective (centuries and millennia) as well as prospective (21st century).

Research themes:

  1. Contamination fluxes, gradients and sources
  2. Erosion, transfers and watershed connectivity
  3. Rivers thermal regime and associated biogeochemical processes
  4. Solid transport and morphodynamics.

The director, professor Marc Desmet, is also in charge of the Sediment Observation Network of the Loire River Basin.

Created in 1998, Géo-Hyd is a consultant firm with dual skills in “Water and environment” and “GIS and applied computing”.  In order to ensure its expertise’s transversality and quality, Géo-Hyd is composed of 30 collaborators (doctors, engineers, masters), divided in two groups:

  1. Scientific and thematic resources: hydrogeologists, hydrobiologists, geographers, environment generalists, doctors in geosciences;
  2. Technical resources and engineering technology: computer scientists, programmers, analysts, GIS specialists, cartographers, data managers.

Among its references, Géo-Hyd has worked with french institutions of the environment and water fields (Agences de l’eau, DREAL, ONEMA, SOeS), research centers (IRSTEA, INERIS, INRA, BRGM), territorial collectivities, industrials (ALCAN/Pechiney, LDC, LAFARGE), agricultural structures and international organizations (French Development Agency, World Bank…). Géo-Hyd also takes part in public/private R&D projects supported by public innovation financing plans.  Its director, Daniel PIERRE, is the 1st Vice-President of the new Competitiveness Pole DREAM Water and Environments.

This has led Géo-Hyd to built a strong experience in mapping, treatment and development geomatics, centralization, management, data recovery and analysis in the fields of water and environment.