Innovations pour la gestion durables de l'eau en ville - connaissance et maîtrise de la contamination des eaux pluviales urbaines. – INOGEV
Innovation for a sustainable management of pollution in cities. Stormwater pollution
The reduction of pollutant discharges to limit their impact on the environment is a major preoccupation of most cities. A multidisciplinary study involving both environmental and social sciences for a better management of pollutant fluxes in cities is proposed. This project aims at helping water managers from local governments to define efficient strategies for the management of pollutant fluxes.
Characterization and quantification of pollutant fluxes. Socio historical analysis of relations between researchers and stormwater managers.
The reduction of pollutant discharges to limit their impact on the environment is a major preoccupation of most cities. Indeed, urban discharges are considered as a major cause of the deterioration observed in receiving waters. Water regulation is becoming more and more stringent. Especially, the Water Framework Directive (Directive 2000/60/EC) setting as an objective a «good ecological and chemical state of surface waterways and groundwater by 2015« fixes drastic reductions of mineral and organic micropollutants (priority substances, emerging pollutants) in water bodies. However, the analysis of these substances is still scarce and often difficult. It is, therefore, necessary to identify the main pollutant sources and their behavior in the urban cycle (atmosphere, impervious surfaces, basins) in order to act efficiently. This project aims at helping water managers from local governments to define efficient strategies for the management of pollutant fluxes by analyzing the transfer of knowledge between research results and technicians. The system considered in this study is an urban separate catchment where different compartments are taken into account (atmosphere, surfaces, catchment outlet). The question is to quantify fluxes and to precise their origin for a better modeling and to propose methods to help local governments in the management of pollutant fluxes and the follow up of the measures they have taken.
The project is composed of 5 tasks : Methodology. Three urban separate catchments were chosen to estimate pollutant fluxes at their outlet. 77 pollutants (metals, polycyclic aromatic hydrocarbons, pesticides, alkylphenols, polybromodiphenyl ethers) were analyzed in the different compartments of these basins (atmosphere, surfaces, catchment outlet). Methodology harmonization was made concerning sampling, analyses, data treatment). Besides, a socio historical analysis of collaborations between researchers and local authorities was made. Characterization of atmospheric pollutant sources and their deposition on urban surfaces. Atmospheric contribution to the global pollution of a catchment was studied through experimentations and modeling. In particular, a focus was made on dry deposition fluxes, seldom studied in urban environments. Characterization and quantification of micropollutant fluxes at the catchment scale. Two approaches were used to better understand wet weather pollutant discharges in urban environments and to model these discharges: a global approach of fluxes measurement and a more detailed approach aiming at better understanding the leaching of pollutants. Analysis of innovation practices in the stormwater management policy of cities. Research is made on the knowledge transfer and the application of innovation results cities. The collaboration between scientists from the 3 observatories in hydrology and local authorities is particularly studied. Management. The objective of this task is to analyze how the results obtained in the previous tasks can be useful to elaborate a sustainable policy in urban environments.
Redaction of protocols for sampling and blank samples. Micropollutant analysis results are available on the INOGEV website and a reflection for a common data base is carried out in the frame of the URBIS SOERE. Dry deposition was measured by means of tracers (fluoresceine and Be). The nature of urban surfaces as well as meteorological conditions, thermophoresis and surface position play a role in dry deposition velocities. For example, there is one order of magnitude between deposition on smooth an rough surfaces. The use of Be as a tracer of atmospheric particles was validated. Particle size and rain intensity influence particle scavenging by the rain. Modeling of urban dry deposition. Many pollutants, which were seldom studied in stormwater were analyzed and a data base available to water managers for the evaluation of the impact of stormwater on the pollution of receiving waters was created. The influence of land cover on stormwater quality at the catchment outlet was low. Pullutant concentrations greatly varied throughout time. A social historical analysis of practices, based on interviews between researchers and technicians was made. The involvement of researchers and local authorities in the coproduction of research programs varies from one observatory to the other; it is higher in Paris and Lyon than in Nantes. The observatories are now recognized at the scientific level (SOERE label). The role of «mediators« as a link between research and public services (for example a former PhD student working for a local authority) is highlighted.
The synergy created through the INOGEV project has reinforced the collaboration between the three French observatories in urban hydrology now regrouped as the URBIS SOERE (Observation and Experimentation System for the Research in Environment). The major results of the project concern:
1) the harmonization of the methods (sampling, analyses, data treatment) in the 3 observatories;
2) the development of a new method for the measure of dry atmospheric deposition and the validation of the use of 7Be as a tracer of atmospheric pollutants;
3) the implementation of a large pollutant data base which will be available to water managers for the evaluation of stormwater impact on receiving waters;
4) the socio historical analysis of the relations between researchers from the 3 observatories and local authorities to favor the knowledge transfer.
The valorization of the results of the INOGEV project was made through :
1) papers in the international literature (e.g. Percot et al., 2013, Use of beryllium-7 as a surrogate to determine the deposition of metal and polycyclic aromatic hydrocarbon through urban aerosols in Nantes, France, Atm. Env. 74 338-345) ;
2) articles in technical the literature;
3) technical workshop (http://www.graie.org/othu/pdfothu/JTOTHU5-ACTES-9fev12web6.pdf);
4) more than 15 international or national conferences (e.g. NOVATECH 2013, EAC 2011, 2012, 2013, etc.) ;
5) micropollutant data base and reports available on the INOGEV website (http://www.irstv.cnrs.fr); 6) closing workshop in Nantes (3-4 December 2013) organized with Nantes Métropole, ONEMA and CERTU.
This project aims at helping local authorities to define efficient strategies for the management of pollutant fluxes, analysing the knowledge transfer between research results and their operational application. The system considered in this study is an urban catchment with a separative system, where 3 compartments are studied: the atmosphere, urban surfaces (roofs, roads’) and the catchment outlet. The originality of the project consists in: Implementing a multidisciplinary approach including social sciences and environment sciences; Maintaining the HURRBIS inter-laboratory network, unique in the world, on a long term basis; Quantifying micro-pollutants in the different compartments to precise their origin; Analysing the mechanisms of knowledge transfer so as to optimize urban sanitation management. The implementation of the project will be based on the experience of HURRBIS inter-laboratory network developed in France during the last 15 years: OPUR (Observatoire des Polluants urbains, in Paris), OTHU (Observatoire de Terrain en Hydrologie Urbaine, in Lyon) et SAP (Secteur Atelier Pluridisciplinaire, inNantes). This inter-observatory synergy will be completed by the competences of other partners, especially for the characterisation and transport of atmospheric pollutants. Socio-politic collaborations between local authorities and researchers will also be taken into account.
Project coordination
The author of this summary is the project coordinator, who is responsible for the content of this summary. The ANR declines any responsibility as for its contents.
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