Groundwater Level Trend Analysis in France over the period 2000-2022

In May 2024, IGRAC calculated the groundwater level trend in French observation wells over the period 2000 – 2022. The results of the calculations contributed to the press article “300 contaminants dans nos nappes: polluant par polluant, notre analyse des eaux souterraines en France". The methodology is described in the report “Updated Methodology for Data Selection and Groundwater Level Trend Analysis," available on IGRAC’s GitHub repository. The objective of this analysis is to statistically evaluate whether there is a significant trend in groundwater levels over time.

The monitoring data were downloaded from the ADES website.

The results are presented in one Excel file and in PNG plots (one per well). The Excel file includes the results of the standard Mann-Kendall Test and the Hamed-Rao Modified Mann-Kendall Test, highlighting whether a trend is detected, along with its slope, significance, and other related parameters described below. The plots show the monthly groundwater level values (blue dots) that were first compiled and selected to identify the Mann-Kendall trend and the Sen's slope (red line).

For any questions, please contact: info@un-igrac.org