The Water, Environment and Urban Systems Laboratory (Leesu) is a research group shared by École nationale des ponts et chaussées and Université Paris-Est Créteil (Research group numbered 200920634U)

Director : Ghassan Chebbo

Deputy Director : Julie Gobert
Deputy Director : Gilles Varrault

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The research object of Leesu is urban water, through various approaches:

• Hydrological and physical studies (water runoff, transfer through urban systems, lake studies),
• Biogeochemical studies about emissions, fate and impacts of chemical and microbiological contaminants in the city/device/receiving environment continuum,
• Studies about politics, water uses, practices and their evolutions.

The Leesu develops a multi- and interdisciplinary research, an applied and involved research in environmental sciences. Our research is in line with major societal issues such as the development of a sustainable city that is resilient to change, the optimization of water resources, the protection of groundwater and aquatic ecosystems...

Its ambition is to develop innovative concepts for sustainable water management in a resilient city, founded in fields of expertise developed in the last 10 years: modeling and the use of models, micro-pollutants and pathogens in human-impacted catchment basins, multiscale approaches, limnology, urban water uses, and urban planning. The approach is interdisciplinary, a balance between in situ observations and/or in controlled lab conditions, and their interpretation, culminating in quantitative and predictive models.

Long-lasting partnerships

Leesu anchors its activities in close and lasting operational partnerships with local authorities in the Paris region and with industrial companies in the water sector.

These partnerships are developed in the Urban Hydrology Observatory OPUR and relies on high-frequency data acquisition, field monitoring devices, as well as Chemical and microbiological analytical platforms. Various sociological investigation techniques (qualitative and quantitative) are also used to understand the social and political uses as well as the implementation of water solutions.

In France, Leesu is a major actor in the field of urban hydrology and has close relationships with other similar observatories, OTHU (Lyon) and ONEVU (Nantes), members of the URBIS network. Leesu is also a member of an Observatory of alpine lakes (OLA). Leesu researchers are also members of national working groups (ANSES, AFNOR, ASTEE, CEP).

International collaborations

Leesu members have close and long-term international collaborations with Brasil (UFMG) and Lebanon (Université Libanaise and Lebanese National Research Center). Since 2014, partnerships have been developed with China and projects started with Vietnam and Africa.
Leesu members are also involved in international scientific networks:

• Working Group of the Joint committee of urban drainage (IWA/IAHR)
• Working Group Microplastics of the ISO
• NORMAN network (Network of reference laboratories, research centres and related organisations for monitoring of emerging environmental substances)