Magali Dechesne

Performance of Stormwater Infiltration Basins on the Long Term

Infiltration basins are good systems to decentralize stormwater management. They are widely used in Lyon, France, as a result of urban development. But, because of topsoil clogging, infiltration basins can become unsustainable over time. This paper defines context indicators for assessing the present state of selected basins: a clogging indicator and a contamination indicator. It is found that clogging increases as a time function. Metals are analyzed at different depths. The topsoil layer acts as a pollutant trap; metals are concentrated in the top 30 centimeters of soil.

Projet « MGD Infiltration »: Maîtrise et gestion durable des ouvrages d'infiltration des eaux pluviales en milieu urbain

ABSTRACT Storm water infrastructures based on pipe networks have reached their limits (concentration of the pollution, increase in flooding risks of and in investment costs). The managers and the designers turn towards new stormwater approaches such as infiltration strategies supposed to be more sustainable (easy integration in urban area, reduction of peak rates and pollution loads of urban runoff by reducing the imperviousness, limitation of stormwater discharges in the watercourses…). However, their development asks questions on their long term behaviour and their real performances must be quantified. The aim of the research that has just been lunched is divided into two parts. The first one (Part 1) is devoted to a better understanding/description of their long term functioning in order to improve design, maintenance and management strategies of the technical systems (Part 2). This second part will be carried out by the means of construction of reliable performance indicators and the development of multicriteria decision aid methods.