Le Bourget-du-Lac, France
Le Bourget-du-Lac, France

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Pezet F.,SAFEGE | Dorioz J.-M.,French National Institute for Agricultural Research | Quetin P.,French National Institute for Agricultural Research | Lafforgue M.,SAFEGE | Trevisan D.,French National Institute for Agricultural Research
Journal of Hydrologic Engineering | Year: 2014

Recent improvements in the Soil and Water Assessment Tool (SWAT) model take account of hydrological processes controlling a variable source area (VSA). This model, SWAT-VSA, accounts for changes in the nature and extent of the VSA over the course of a hydrological cycle by considering global catchment storage capacity, which varies with soil moisture between threshold values whose spatial distribution is determined by topography. The objective of this work is to evaluate the contribution of several aquifers with specific storage capacities to global catchment storage, its dynamics; and subsequent effects on VSA and non-point-source pollution. For this purpose, a method called SWAT-mVSA (SWAT-multi VSA) was used in a catchment representative of the agricultural conditions of large perialpine lakes to calculate soluble reactive phosphorus (SRP) fluxes because SRP has a major influence on receiving waters. SWAT-mVSA predicted components of the hydrological balance and SRP fluxes more accurately than SWAT-VSA. This underlines the importance of VSAs in mobilizing and transporting non-point-source pollutants such as nutrients, pesticides, or bacteria. © 2014 American Society of Civil Engineers.


Mirats-Tur J.M.,CETaqua | Jarrige P.-A.,SAFEGE | Meseguer J.,CETaqua | Cembranoa G.,CETaqua | Cembranoa G.,Polytechnic University of Catalonia
Procedia Engineering | Year: 2014

This paper presents the practical results obtained on the field from two different methods for identifying and locating leaks in water distribution systems using network modeling based algorithms. Both methods are based on the sensitivity analysis of pressure measurements to the demand variation in any node in the distribution system. This work is mainly focused on the obtained results using both methodologies in two different leak episodes, both in Icaria pilot DMA sector in Barcelona. The first episode is a non-calibrated real multi-leak scenario. The second episode was a calibrated artificial leak. Results are similar for both methods, and the identification of location of leaks is found within 150 meter from the actual leaks. © 2013 The Authors.


Metadier M.,Safege | Metadier M.,CNRS Laboratory of Civil and Environmental Engineering | Bertrand-Krajewski J.L.,CNRS Laboratory of Civil and Environmental Engineering
Water Science and Technology | Year: 2011

Continuous high resolution long term turbidity measurements along with continuous discharge measurements are now recognised as an appropriate technique for the estimation of in sewer total suspended solids (TSS) and Chemical Oxygen Demand (COD) loads during storm events. In the combined system of the Ecully urban catchment (Lyon, France), this technique is implemented since 2003, with more than 200 storm events monitored. This paper presents a method for the estimation of the dry weather (DW) contribution to measured total TSS and COD event loads with special attention devoted to uncertainties assessment. The method accounts for the dynamics of both discharge and turbidity time series at two minutes time step. The study is based on 180 DW days monitored in 2007-2008. Three distinct classes of DW days were evidenced. Variability analysis and quantification showed that no seasonal effect and no trend over the year were detectable. The law of propagation of uncertainties is applicable for uncertainties estimation. The method has then been applied to all measured storm events. This study confirms the interest of long term continuous discharge and turbidity time series in sewer systems, especially in the perspective of wet weather quality modelling. © IWA Publishing 2011.


Metadier M.,Safege | Metadier M.,INSA Lyon | Bertrand-Krajewski J.-L.,INSA Lyon
Water Science and Technology | Year: 2011

With the increasing implementation of continuous monitoring of both discharge and water quality in sewer systems, large data bases are now available. In order to manage large amounts of data and calculate various variables and indicators of interest it is necessary to apply automated methods for data processing. This paper deals with the processing of short time step turbidity time series to estimate TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) event loads in sewer systems during storm events and their associated uncertainties. The following steps are described: (i) sensor calibration, (ii) estimation of data uncertainties, (iii) correction of raw data, (iv) data pre-validation tests, (v) final validation, and (vi) calculation of TSS and COD event loads and estimation of their uncertainties. These steps have been implemented in an integrated software tool. Examples of results are given for a set of 33 storm events monitored in a stormwater separate sewer system. © IWA Publishing 2011.


Metadier M.,Safege | Metadier M.,INSA Lyon | Bertrand-Krajewski J.-L.,INSA Lyon
Water Research | Year: 2012

This paper presents one of the largest databases on the quality of urban wet weather discharges measured since the development of continuous in-sewer water quality sensors in the late 1990s. Five years of continuous turbidity measurements enabled the validation of 263 and 239 rainfall events, respectively on two experimental catchments in Lyon (France), Chassieu (185. ha separate sewer) and Ecully (245. ha combined sewer). Except for high rainfall events of summer and second half of winter, analysis of database representativeness showed that all seasons were relatively well represented. As a first analysis of the database, traditional tools used in the urban drainage field were applied to assess: i) statistics and analysis of distributions of TSS and COD events loads and event mean concentrations (EMCs) and ii) the correlations between these statistics and events characteristics and iii) M(V) curves describing the intra-event mass distribution. Results showed that: i) EMCs and loads were approximately log-normally distributed, with a clear impact from wastewater contribution in Ecully, ii) EMCs are not correlated with storm event characteristics, whereas loads have shown significant correlation with key storm event variables such as total event volume, rainfall depth, maximum rainfall intensity and discharge and iii) M(V) curves dynamic could be classified in three categories, however with no clear correlation with storm event characteristics. The visual analysis of continuous time series of TSS and COD pollutographs, derived from turbidity time series showed that event pollutographs were highly variable, due to complex interacting processes during and between events, and suggests that further progress in knowledge and modelling of urban wet weather pollutant loads and pollutographs should be based on more detailed analyses of continuous time series rather, than on the traditional single event approach. © 2011 Elsevier Ltd.


Floriat M.,Safege | Gandouin C.,Safege | De Lombardon A.,Cabinet dAvocats Verdier Le Prat | Verdier L.,Cabinet dAvocats Verdier Le Prat
Techniques - Sciences - Methodes | Year: 2013

As pluvial basins often use large space in our urban environment, it is now necessary to think differently in order to share this space with different uses of the hydraulic structure. Based on Safege return experiences, this article presents the principles for a shared space, the difficulties observed and how, own to juridical and technical conceptions, we are able to securise and carry out such a project.


The 27th of January 2012 decree aims at reducing water intake for potable uses, at improving drinking water networks efficiency and sustainability, and enhancing financial management of these networks. Moreover, by imposing an objective of yield, this decree indirectly implies an increase of the rhythm of renewal of the drinking water networks.


Vincent L.,SAFEGE | Michel L.,SAFEGE | Catherine C.,SAFEGE | Pauline R.,SAFEGE
Water Science and Technology | Year: 2014

Finding alternative resources to secure or increase water availability is a key issue in most urban areas. This makes the research of alternative and local water resources of increasing importance. In the context of political tension with its main water provider (Malaysia), Singapore has been implementing a comprehensive water policy for some decades, which relies on water demand management and local water resource mobilisation in order to reach water self-sufficiency by 2060. The production of water from alternative resources through seawater desalination or water reclamation implies energy consumptive technologies such as reverse osmosis. In the context of increasing energy costs and high primary energy dependency, this water self-sufficiency objective is likely to be an important challenge for Singapore. The aim of this paper is to quantify the long-term impact of Singapore's water policy on the national electricity bill and to investigate the impact of Singapore's projects to reduce its water energy footprint. We estimate that 2.0% of the Singaporean electricity demand is already dedicated to water and wastewater treatment processes. If its water-energy footprint dramatically increases in the coming decades, ambitious research projects may buffer the energy cost of water self-sufficiency. © IWA Publishing 2014.


In 2006, DEFACTO, the public institution for the planning of La Défense district ordered a study to estimate the consequences of a 1910 type flood on the district of La Défense 10 and to define actions to reduce flood vulnerability. The company SAFEGE has been chosen to work on this study. Two main steps have been followed. The first one consisted in doing a diagnosis of buildings vulnerability but also of other elements that could affect the companies work. Visits and meetings have been organised to define which elements would be flooded. This work led to analyse the equipment's vulnerability but also the direct impact of the flood. The second part of the study consisted in proposing actions to reduce flood vulnerability. It was based on an estimation of minimal needs for the company to be able to work. Two scenarios have been studied. The first one proposes no change compared with the initial situation. It is made to determine the length, work and costs that would be necessary to repair the damage. The second one is to propose preventive and curative actions to reduce flood vulnerability.The global aim is to guarantee the continuity of the companies' work. © Société Hydrotechnique de France, 2011.


This paper presents one of the largest databases on the quality of urban wet weather discharges measured since the development of continuous in-sewer water quality sensors in the late 1990s. Five years of continuous turbidity measurements enabled the validation of 263 and 239 rainfall events, respectively on two experimental catchments in Lyon (France), Chassieu (185 ha separate sewer) and Ecully (245 ha combined sewer). Except for high rainfall events of summer and second half of winter, analysis of database representativeness showed that all seasons were relatively well represented. As a first analysis of the database, traditional tools used in the urban drainage field were applied to assess: i) statistics and analysis of distributions of TSS and COD events loads and event mean concentrations (EMCs) and ii) the correlations between these statistics and events characteristics and iii) M(V) curves describing the intra-event mass distribution. Results showed that: i) EMCs and loads were approximately log-normally distributed, with a clear impact from wastewater contribution in Ecully, ii) EMCs are not correlated with storm event characteristics, whereas loads have shown significant correlation with key storm event variables such as total event volume, rainfall depth, maximum rainfall intensity and discharge and iii) M(V) curves dynamic could be classified in three categories, however with no clear correlation with storm event characteristics. The visual analysis of continuous time series of TSS and COD pollutographs, derived from turbidity time series showed that event pollutographs were highly variable, due to complex interacting processes during and between events, and suggests that further progress in knowledge and modelling of urban wet weather pollutant loads and pollutographs should be based on more detailed analyses of continuous time series rather, than on the traditional single event approach.

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