The past week was marked by a lack of rainfall, leading to stable or declining water levels in Île-de-France. While the situation remains generally stable on major watercourses, the Marne at Gournay is experiencing significant artificial variations due to dam work. Small watercourses have also shown a stable trend.
At the end of September, groundwater levels are mostly around average or moderately low in several areas of the region, such as Buhy, Bréva, and Perdreauville. The 2025-2026 recharge period, concentrated in February, was deemed short and of low intensity. The drainage period, which began in March, continues with an overall downward trend. The Buhy piezometer crossed its alert threshold in week 32, while those in Mareil-le-Guyon and Bréval reached their vigilance threshold in weeks 37 and 38 respectively.
Some light to moderate rainfall is anticipated for the coming week. However, the water situation is expected to remain stable at already very low levels, with a possibility of temporary improvement in the absence of significant new precipitation.
For further information or to subscribe to the drought bulletin's mailing list, you can contact DRIEAT Île-de-France via email at: DRIEAT-if.etiage@developpement-durable.gouv.fr.
The provisional publication calendar for drought bulletins aims to provide regular information to prefectures for the implementation of restrictive measures and to standardize the processing of hydrometric data. From October onwards, the weekly publication of bulletins will depend on the evolving situation.
