This March, Spain experienced significant rainfall that could have replenished its water supply by more than 6,000 hectometers cubed, equivalent to the annual consumption of its population.

However, this water has largely been released into the sea due to the non-execution of over one hundred reservoirs and dams outlined in the National Hydrological Plan (PHN), initially approved in 2001.

The PHN, set in motion by former Prime Minister José María Aznar's government, proposed the construction of 863 water management infrastructures, including transfers, channels, dams, reservoirs, and desalination plants.

The ambitious plan required substantial funding but faced strong opposition from environmental groups, particularly in regions such as Catalonia and Aragon.

Following his election win in 2004, Prime Minister José Luis Rodríguez Zapatero repealed the most ambitious project of the PHN, the Ebro River transfer, which was designed to supply water to regions including Barcelona, Valencia, Murcia, and Andalusia.

As of now, two decades later, many of the key reservoirs and dams remain unbuilt, often due to environmental concerns, lack of funding, or cost-benefit evaluations.

In the 2023 hydrographic plans revision decree, the Ministry of Ecological Transition revived 29 of these delayed projects, which collectively aim to provide an additional storage capacity of 3,400 hectometers cubed.

However, almost 70 dams and reservoirs have been permanently shelved.

The National Federation of Irrigation Communities (Fenacore), under the leadership of Juan Valero, has called for expedited construction of these infrastructures, asserting that they not only address agricultural needs but can also save lives during extreme weather events.

Some ongoing projects have already encountered years of delays.

Valencia city avoided damage from flooding caused by a Delta Weather System (DANA) last October, largely due to the redirection of the Turia River’s course implemented after deadly floods in 1957. Valero emphasizes this as proof that hydrological infrastructure prevents loss of life.

The original 2001 hydrological plan included the construction of four dams in the province of Valencia designed to contain cyclical floods: the Marquesado dam (capacity of 240 hm3) on the Magro River, the Vilamarxant dam (40 hm3), the Estubeny dam on the Sellent River, and the Montesa dam (15 hm3) on the Canyoles River.

None have been developed.

In 2008, the Ministry of Environment announced the abandonment of the Marquesado dam project, estimated to cost approximately 30 million euros, due to soil conditions that could jeopardize its safety.

The dam was intended to mitigate overflow on the Magro River, which experienced flooding last October that affected towns such as Utiel.

Four years later, during a period of severe budget constraints with Spain approaching an international bailout, the Rajoy government canceled a bidding process for the construction of the Sellent Dam, which was planned to rise 70 meters and protect regions in Costera and Ribera.

Additionally, the Vilamarxant and Montesa dams, designed to manage river overflow in localities like Camp de Turia and l'Horta, have also remained unconstructed.

The Cheste dam announcement in 2004 by the Zapatero government aimed to control runoff in 16 municipalities by the Poyo ravine, which suffered significant flooding last October; however, this project was never realized and would have been inadequate for a flood that exceeded 100 hectometers if constructed as planned.

In the Murcia region, several dams anticipated in the PHN have also gone unbuilt over the past two decades.

These include the Lébor dam (15 hm3) on the Guadalentín River, and the Torregorda dam (10 hm3), among others, which were intended to enhance irrigation in the area.

Through the 2023 decree, the Ministry now prioritizes the construction of four new projects in Murcia: the Béjar, Tabala, Torrecilla, and Nogalte dams, which will collectively provide a storage capacity of 22 hectometers cubed.

The repeal of the Ebro transfer has rendered many of the PHN’s projects obsolete, including proposed reservoirs such as Biscarrués (200 hm3) in Huesca, Jánovas (86 hm3) in the Aragón Pyrenees, and Barrón (30 hm3) on the Arga River in Navarre, all of which faced environmental resistance.

The Ministry is now focusing on projects that have faced significant challenges previously, such as enlarging the Yesa reservoir in Navarre, which aims to expand its capacity from 400 to 1,500 hectometers cubed.

This project has been delayed due to technical changes and legal disputes but is expected to be completed by 2027. Similarly, the Mularroya dam (103 hm3) in Zaragoza is nearing completion after several years of setbacks.

March 2023 became the rainiest month since 2018, boosting built reservoirs to an average capacity of 71%.

Just last week, reservoirs benefitted from over 3,000 hectometers cubed of input.

However, rainfall distribution has been uneven across the Peninsula, with regions like Madrid experiencing record downpours, while reservoirs in the Segura River still remain below their average capacity over the last decade.

Barcelona has faced ongoing water supply issues, resorting to blending desalinated water with river water from the Ter, and even considering shipping water from the Sagunto purification plant in Valencia.

The Ebro transfer was originally intended to mitigate such challenges in the eastern Spanish regions.

In Andalusia, several proposed dams from the PHN remain unrealized, including the San Calixto dam (40 hm3) on the Guadiana Menor, which was meant to supply water to Granada and Jaén, along with the Coronada dam (60 hm3) in Huelva.

The Ministry of Ecological Transition is now looking to revive other proposed projects in Andalusia, such as the Gibralmedina dam (70 hm3), which is under design by the Andalusian government, and the Cerrad dam (290 hm3) in Jaén.

Additional projects in the Cádiz province include five potential dams: Charco Redondo (80 hm3), Zahara (222 hm3), Almodóvar (5.6 hm3), Arcos (15 hm3), and El Álamo (228 hm3).

In Huelva, three significant projects await government attention: Alcolea (274 hm3), Piedras (70 hm3), and improving the Andévalo dam (up to 250 hm3).