The impact of the 2016 flooding on water quality

Part of ZA Seine, PIREN-Seine, GIP Seine Aval and AESN have presented a summary of the research performed on the impact of the 2016 floods on water quality.



Following the floods of June 2016, and in response to requests from the authorities in the Seine-Normandy basin, the Agence de l'Eau Seine-Normandy brought together all of its partners in order to take stock of the impact of this milestone event on the river’s water quality.

Following extensive collaborative work involving numerous stakeholders and research bodies in the water domain, PIREN-Seine and GIP Seine Aval, a part of ZA Seine and in partnership with AESN, presented a summary note to the Basin Committee on 6 April 2017 summarising the impact of the Spring 2016 flooding on the quality of the water in the Seine basin. This summary identifies a degradation, which although present remains moderate, of a number of water quality indicators, such as a drop in dissolved oxygen and an increase in nitrate quantities following heavy rainfall, or even an increase in hydrocarbons in certain areas. A trend decrease in PCB sediment contamination was also noted, the result of a proactive ban since 1987.

The note also provided the opportunity to promote the harmonisation of data and resources by a variety of stakeholders, which enabled the production of a detailed and precise report covering the entire basin. Hailed by all of the stakeholders involved, this collaboration must now continue beyond this summary, and enable the integration of increasing numbers of observations, data and results in order to offer a global vision of the basin.


Download the summary


Partners and data providers:


Conseil départemental de l’Yonne

Conseil départemental du Val de marne

Eau de Paris

Mairie de Paris

SEDIF - Syndicat des eaux d’Île de France

SIAAP Syndicat interdépartemental pour l'assainissement de l'agglomération parisienne

Suez - Agences d’Ile de France

Syndicat de l'Orge Aval

Syndicat Intercommunal d'Aménagement, de Réseaux et de Cours d'Eau

Syndicat Intercommunal pour l'Aménagement Hydraulique de la Vallée de l'Yvette

Syndicat mixte du bassin supérieur de l'Orge Arceau

Syndicat mixte pour l'Assainissement et la Gestion des eaux du bassin versant de l'Yerres

Union des fédérations de pêche du bassin Seine-Normandie

Le Cedre

GIP Seine Aval


Cellule de transfert du PIREN-Seine (Association Arceau-IDF)

Agence française pour la biodiversité (ONEMA)

DRIEE Ile de France

Agence de l’Eau Seine-Normandie