Stable

Yesterday I wrote about forests showing drought stress. Today the picture is more nuanced: drinking water reserves are holding, but rivers and streams are in trouble.

The Esch-sur-Sure reservoir sits at about 316.5 metres above sea level, holding roughly 42 million cubic metres of water. That is nearly four metres above the lowest level ever recorded, back in 2011. Rain in March and April, plus significant rainfall upstream in Belgium, filled the reservoir to near its maximum of 319.5 metres before summer began.[1]

The respite is partly seasonal. Schools are closed, people are on holiday, and the collective construction pause in August means lower consumption. Marc Hans, Director of the Water Management Agency, warns this is temporary. When holidays end and consumption rises again, reserves could deteriorate quickly without sustained rainfall.[2]

SEBES, the syndicate that processes the reservoir water, is currently producing 75,000 cubic metres of drinking water per day. August is typically quieter at 60,000. The facility can handle up to 110,000 cubic metres daily, and additional groundwater sources can be activated if needed.[1]

Rivers are a different story

While the reservoir is fine, rivers and streams in northern Luxembourg are recording levels lower than anything seen during the 2022 drought. Low water means higher temperatures, less oxygen, and more concentrated pollutants. Migration routes for fish and aquatic insects get cut off when stretches dry out entirely.[2]

Restoring groundwater takes longer than fixing river levels. The soil needs to be thoroughly soaked before water can seep into aquifers, a process that can take up to two months. Brief heavy showers do not help. Sustained rainfall over weeks is what is needed.[2]

A pouch in Housen

In Parc Housen, a municipality in the north, they installed a water pouch that can hold 1,200 cubic metres. When the local swimming pool closes for maintenance, the water goes into the pouch instead of being discharged into the River Our. It is then used to irrigate football fields at night, and the fire brigade can tap it for firefighting. The pilot project cost about 200,000 euros, with 175,000 covered by the state.[3]

Simple, practical, and the kind of thing every municipality with a pool could replicate.

Three pillars

The Water Management Agency is working on three fronts: reducing consumption, protecting groundwater better, and developing new sources. One potential future source is the Moselle river, whose water could be treated for drinking. A national vigilance phase remains in place, but a red alert with nationwide restrictions has never been declared in Luxembourg.[2]

The good news: the tap is not about to run dry. The uncomfortable truth: the ecosystem around the tap is already hurting.