Weather: records of rain fell in Charente-Maritime during the month of September

Thursday 10th October 2024 05:10 AM

It’s been a while since we’ve been so wet in the two Charentes. Rain has been a part of our daily lives for several months, the result: the soils are waterlogged. Records were set in September, notably in La Rochelle: 105.6 millimeters of rain in one month of the start of the school year, never seen since 2000 ! In Cognac, the average since 1991 was 62 millimeters; in comparison, there were 128 millimeters this month.

“We haven’t had this much rain since September 1999”

Precipitation well above normal, accumulations sometimes “one and a half to two times higher than normal” for the month of September, the figures are glaring. “In addition, this was the case in previous months, which means that we have had excess rain for some time,” completes Frédéric Montigny, Water project manager at the Nouvelle Aquitaine Regional Biodiversity Agency.
Since last September, both departments have experienced surpluses “of the order of plus 30 plus 60% above normal over the entire period”. A monthly record dating from September 2000 was broken in La Rochelle. The hydrologist summarizes: “we haven’t had this much rain since September 1999 with the passage of a storm at that time.”

Tablecloths and watercourses at very high levels

Consequence which results from these bad weather: the groundwater tables are full. The situation is “largely favorable“and quite new; not usual at this time of year.”All the piezometers in the two departments indicate a level above average, with even more than half of the measuring stations indicating very high levels for the period.
The flow of watercourses is also affected, they have tended to increase, “with values sometimes almost double what is observed for the flow rates of certain rivers on the Charente for example, whether upstream or downstream..

There are already risks of flooding, with some yellow alerts, particularly in neighboring departments. The hydrologist recalls that there is the Vigicrue website, “with daily bulletins, or even a little more frequent than that. They look at the water levels which make it possible to calculate the flow of waterways based on the expected precipitation.”