La Concepción Reservoir: A Paradox of Abundance and Scarcity
La Concepción, the reservoir that supplies drinking water to a significant portion of the western Costa del Sol, is a perfect representation of the Mediterranean climate’s paradoxes and the province of Malaga’s relationship with this vital resource. Just over a year ago, the province was grappling with a severe drought. However, a year later, water had to be discharged for safety reasons and due to the reservoir reaching full capacity. If the water hadn’t been drained, the reservoir would have held one and a half times its capacity.
Preparing for a ‘Dead’ Reservoir
The Junta de Andalucía, as part of its drought plans, is now working on a project to maximize the use of the reserves in case the reservoir reverts to being classified as a ‘dead’ reservoir. A ‘dead’ reservoir is a somewhat outdated term that refers to when the water level drops below the water supply intakes, leading to a significant decrease in water quality due to increased sediment and organic matter and reduced oxygen levels.
Addressing the Last Drop
During the 1995 drought, the reservoir was left with only 0.4 million cubic meters of water. Various systems were put in place in stages at that time, but three decades later, they require a comprehensive overhaul. The project, designed by Irtene and SGS, has an initial budget of 1.1 million euros, including taxes, which the regional government has recently put up for tender.
Replacing the Deteriorated Pipe
In November 1981, an asbestos cement pipe was installed, which has logically deteriorated after more than 40 years. In 1995, three submersible pumps were installed on the dam’s surface, driving approximately 400 liters per second from a height of 44.00 meters to the intermediate intake at a height of 76.50 meters.
Considering Three Alternatives
Different alternatives have been explored to recover the reservoir’s extraction capacity in the event of a drought. The pros and cons of three alternatives have been analyzed. The first is to install a floating intake in the reservoir with submersible pumps. The second is an in-line pumping system, which would involve integrating the pumping equipment into the pipeline that currently connects the bottom outlet with the intermediate intake. The third would involve using the stilling basin when the water flows out of the dam’s spillway. Two possibilities are being considered for this option, with the preferred one being an independent conduction from the stilling basin to the existing impulsion conduction that connects with the outlet channel.
