Rainwater tanks to prevent flooding in periods of heavy rainfall

On Saturday, the storms, which continued until Sunday morning, swept several areas such as Tarragones, Bex Camp, Valles or Maresme, reaching in cities such as Arenys de Mar 28 liters in half an hour.

big Rain showers of short duration, but of great intensityWhich in many cases ended The sewer system overflows They turned the streets into canals.

In periods of heavy rain, more than 40 liters can fall in Barcelona in 30 minutes. This water is filtered through the sewer and joins the sewage in the sewerage network which does not reach on such days. This generates a High risk of flooding.

Underground, the way to avoid them is… Rain tankswhich maintains an uncontrolled flow of water which, in the face of an increasingly heavy and heavy rainfall scenario, becomes more necessary, according to Gustavo Ramón, Operations Director of Barcelona Cycle de Ligua.

“We store this water during rainfall, and after it passes and the level drops, we empty the tanks into the sewage network. This prevents flooding in the city and reduces the impact of residual water and rainwater draining onto the beaches.”

Now, in the city there Fifteen rain tanksWhich began construction in the nineties.

The underground reservoir in Joan Miro Park, which was opened in 2003, has a total capacity of 55,000 cubic metres, equivalent to the volume of water 22 Olympic swimming pools. With a depth of 17 metres, it regulates the flows of the Tarragona Avenue complexes to prevent flooding in the Gran Via area, the Zona Franca promenade and the Ciutat Vella.

On average, this large tank is filled two or three times each year. But everything has changed as a result of the current drought. With little rain, the reservoirs have not been 100% full in three years. According to Ramon, it is now “full to 20, 30 or 50% maximum.”

This tank contains two ships. One is drained by gravity and the other is emptied by pumps. But there is no benefit from water in one or the other.

“We store water and then treat it in purification plants, because it is highly polluted, and carries wastewater and what rainwater carries.”

Looking to the coming years, the city council plans to build more tanks. The problem is that the climate crisis has made rainfall less, but when it does, storms become more ferocious.