A deluge from Storm Regina has pushed Catalonia’s internal water reservoirs to the brink of full capacity, a dramatic reversal of fortune following years of severe drought. The sustained downpour has filled the region’s basins to levels unseen in years, compelling the Catalan Water Agency (ACA) to conduct controlled releases from several dams to ensure safety and manage the sudden surplus.

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The current situation presents a stark contrast to March 2024, when the reservoir system hit a historic low of just 14%, plunging the region into a water crisis. A slow recovery began in the spring of 2024, with a succession of storms gradually replenishing reserves. Winter downpours then pushed capacity levels past 93% earlier this year. Now, Storm Regina appears to have completed the recovery, bringing a new set of challenges.

From Historic Lows to Overflowing Dams

According to the latest data from the ACA, the reservoir system for Catalonia’s internal basins has reached 98.7% of its total capacity. The Ter-Llobregat system, which supplies water to the Barcelona metropolitan area and over two million people, is at a remarkable 99.8%.

Several reservoirs are now exceeding their theoretical limits. The Susqueda reservoir, the largest in the internal basins, is currently holding 102% of its capacity. This has created the striking image of water spilling over the top of the dam, forcing authorities to increase its outflow to 200 cubic metres per second-a massive jump from the typical ecological flow of 4.6 cubic metres per second. This release has put the River Ter on alert downstream.

Other reservoirs are also over capacity, including La Llosa del Cavall and the small Riudecanyes reservoir. The Pasteral reservoir, critical for the water transfer to Barcelona, has reached an astonishing 128% of its standard capacity, as reported by VilaWeb. Meanwhile, major dams like La Baells and the Darnius-Boadella are both hovering at 97%.

Widespread Disruption and Emergency Alerts

While the rain is a blessing for water security, Storm Regina has caused significant disruption. The Montseny massif experienced some of the heaviest rainfall, with 234 litres per square metre at Puig Sesolles and 200 l/m² in Viladrau. These intense accumulations have saturated the ground and swelled rivers, creating hazardous conditions.

Emergency services were stretched thin. The 112 emergency line received over 500 calls related to more than 340 incidents by Saturday morning. In Llinars del Vallès, emergency teams are still searching for the driver of a van that was swept away by the swollen Mogent river.

The storm also impacted the region’s infrastructure. A landslide on the N-260 road between Ripoll and Sant Joan de les Abadesses injured a man and forced its closure. Flooding and further landslides shut down several other local and regional roads, according to the Catalan Transit Service.

A New Challenge: Managing Abundance

Although Storm Regina is beginning to lose intensity over Catalonia, Protecció Civil, the Catalan civil protection agency, is keeping its INUNCAT flood alert plan active. Officials warn that the risk of sudden river level rises remains high due to the saturated soil and ongoing dam releases. The high flows of the Muga and Ter rivers continue to be a primary concern.

The Ebro Hydrographic Confederation (CHE) has also issued warnings for potential flash floods in smaller rivers in the south of Catalonia. The focus for authorities has now pivoted from managing scarcity to carefully managing an abundance of water, a challenge Catalonia has not faced for several years.