Recent heavy rainfall in Wallonia has put several rivers on pre-flood alert, according to the latest update from the Walloon public service’s Hydrometry portal. While several rivers are affected, the alert thresholds are not expected to be reached. The channeled Dender and its tributaries may reach pre-alert thresholds in the middle of the day. The Senne basin’s expected increase in flow should be contained in flood retention structures and not cross pre-alert thresholds. Eastward, pre-alert thresholds could be reached Saturday afternoon on the Vesdre and its tributaries and Saturday evening on the Our. The Royal Meteorological Institute has issued a yellow rain warning from Friday to Sunday for light but continuous rains.
Due to the heavy rains observed in recent days, several rivers located in Wallonia were on pre-flood alert on Saturday morning, according to the latest update of the Hydrometry portal of the Walloon public service (SPW). In the current state of forecasts, however, the alert thresholds should not be reached.
Several rivers are affected. The pre-alert thresholds could thus be reached in the middle of the day on the channeled Dender and its tributaries. The increase in flow expected in the Senne basin should be able to be contained in the flood retention structures (empty and operational), and ultimately not cross the pre-alert thresholds.
The same reasoning applies to the Charleroi-Brussels canal. Further east, the pre-alert thresholds could on the other hand be reached this Saturday at the start of the afternoon on the Vesdre and its tributaries and at the end of the afternoon on the Amblève and its tributaries.
In the middle of the evening, the Our could follow. Regarding the Ourthe (middle and upper), the pre-alert thresholds could be crossed overnight from Saturday to Sunday in the downstream part of the basin, while overruns in the upstream part of the basin cannot be ruled out. For the upper and middle Semois, the Sure and the Chiers, heavy rainfall has been observed in the Semois basin (up to 30 l / m² locally) in the past 24 hours, notes the SPW.
Coupled with the precipitation forecast by Sunday midnight, the pre-alert thresholds could be reached in the upstream areas of the basin and the flows could remain around the pre-alert threshold until Sunday inclusive.
The Royal Meteorological Institute has issued a yellow rain warning for the period from Friday 4:00 p.m. to Sunday 12:00 a.m., during which the rains are expected to be light but continuous.
As the heavy rains continue to pour down in Wallonia, several rivers remain on pre-flood alert. However, the latest updates reveal that the alert thresholds should not be reached. While some rivers may still pose a potential risk, the flood retention structures are well-prepared and operational to contain the expected increased flow. With the Royal Meteorological Institute issuing a yellow rain warning, it is essential to monitor any further developments closely. Stay safe and stay alert during this unpredictable weather.