The lower section of the Besòs is on its way to becoming a fundamental tap to ensure water supply in the Barcelona region. A set of actions in the lower basin of this river will allow the volume of resources that can be used to be multiplied by four. Among the most outstanding actions are the project to carry out, for the first time, a direct capture of water from the river, with the forecast that it will go into production at the end of the year or at the beginning of next year. Until now, the intakes were only underground.
The president of the Generalitat, Pere Aragonès, announced yesterday an investment of 25 million to multiply by four the utilization of the flows of the Besòs potable water station, in the neighborhood of Trinitat Vella, which supplies the network of Barcelona and the metropolitan area. These 25 million will be advanced by the Catalan Water Agency (ACA) and will be used to finance works that are part of the short-term measures against the drought by the Generalitat.
The current drought will cause the center of gravity on the availability of new resources to move to El Besòs. Until now, the main taps that supply the Barcelona region are the Ter and Llobregat reservoirs, the Prat and Blanes desalination plants and the reuse of regenerated water at the Prat treatment plant. Now, instead, the lower stretch of Besòs will play an important role. It is quite a paradox, since the groundwater of this river has been abused throughout the last century, to the point that its high pollution caused it to stop being used for domestic purposes. However, between the years 1990 and 2000 these flows (captured in Trinidad) were again made drinkable thanks to modern technologies (reverse osmosis), effective enough to treat drinking water.
The experts point out that these underground reserves in Besòs do not suffer from very remarkable pollution caused by a specific pollutant, but rather a very varied pollution of small amounts. A miracle in the treatment makes it possible to drink with the new techniques. "What comes out of the plant is almost distilled water, which must be mineralized to be suitable for human consumption", say sources from the Agbar company.
Now 200 liters per second of water from the aquifer are made potable at the Besòs de Trinitat station. But a plan will be pushed to increase the intakes, up to 860 liters per second (a little less than what a reservoir of 30 hm3 stores, three times the volume of Siurana), between underground waters (of the aquifer) and superficial (of the river itself). The actions will take place between the end of this year and the beginning of the next.
First of all, a facility that was about to start operating during the drought of 2008 will be remodeled and modernized, so that it will now be possible to improve the catchment to increase production up to 400 l/s a from the month of June.
"There is a lack of water from the aquifer, the wells are very low and do not give us all the water we need", say sources in Agbar.
For this reason, the second innovative action will be to take advantage of and make potable the flows of Rec Comtal, a millenary hydraulic work at the entrance to Barcelona that transports underground water that emerges. The goal is to use all its available water.
A canalization of about four kilometers of the Rec Comtal has been preserved, which runs between the outcrop at the confluence of the Besòs and Ripoll rivers and its mouth in the Besòs. Currently, the Rec Comtal transports between 500 and 600 liters per second. "The idea is to capture these flows so that they are not wasted", say the same sources.
The problem now is that this facility runs outdoors and there is a risk of contamination. Therefore, to avoid this danger, a large pipeline will be built parallel to the Besòs river, so that it will link the source of the Rec Comtal and the water treatment plant. This new line, which will be about six kilometers long, will be an emergency work, and will run parallel to the river, in an area of public hydraulic domain, which will reduce the impacts.
Finally, it is planned to carry out a first abstraction of surface water (directly from the Besòs River) of 300 l/s, which must be ready by the end of the year or the beginning of 2024, in the same way than the set of performances. The forecast is that these two new investments (the use of Rec Comtal and the first direct capture of the river) will go through strict treatment systems (ultrafiltration and reverse osmosis).
Pere Aragonès stated that the solution to the current drought is "to make more efficient use of water and have new infrastructures". "We cannot control the intensity of the drought or its duration, but we must be prepared to face the most serious situations, we must be prepared for the worst situations, including those of extreme harshness," he added.
The president defended that the investments to deal with the drought should not be counted in the deficit of the public administrations of budgetary discipline. "The current regulations on budgetary stability establish that natural disaster priorities can be exempted from meeting the deficit. I think it is a good example", he warned.
