Malaga loses twice as much water as it needs due to lack of dam río Grande river

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Up to 3,000 litres per second flow downstream of the Aljaima weir, which can only harness surface water, without the capacity to store it

Chus Heredia

Malaga

Monday, 22 December 2025, 16:27

The Río Grande river in Malaga province is running with a high flow rate at the moment. This is due to rainfall and snowfall in Sierra de las Nieves. The water is of very good quality and eventually flows into the Guadalhorce. There, at the Aljaima weir, it is used by the city's municipal water company Emasa, which also sends raw water to Cártama (around 100 litres per second). However, the system can only make use of the water as it flows, with a very limited storage capacity. This means that any excess flow spills over the dam and continues downstream. At present, the overflow reaches 3,000 litres per second, according to SUR sources.

This is twice as much water as what the city needs to have circulating in its network: between 1,500 and 1,600 litres per second, depending on the time of year.

1,600

litres per second is the flow that Malaga needs for its urban supply

The Río Grande's water, therefore, is now only used when it flows. Given the conditions of the river, that means many months of the year. The water is of very good quality, which does not rule out the possibility of drags and excess turbidity, especially in times of storms. The fact that it cannot be stored means that it does not decant and sometimes its use has to be stopped momentarily, as happened a few days ago.

Well system

The system collects water from the right bank of the river and sends it through a channel to a large tank where the flows from the 16 wells of the Aljaima-Fahala system, which have been rehabilitated by the regional government of Andalucía and the city council, also accumulate. Their maintenance is also costly. The casings, pipes, pumps, electrical systems, incrustation prevention measures, quality control must always be in good working order. In fact, Emasa has just put out to tender a contract for these resources and the five that have just been added in Bajo Guadalhorce (three in Perales and two in Puente del Rey).

Aljaima-Pilones-Atabal

At Aljaima, only a small amount of sodium hypochlorite is added to prevent damage from zebra mussels. From there, the water is sent to the El Atabal desalination plant. Beforehand, the equivalent of about two weeks' consumption can be stored in the small El Tomillar reservoir (Pilones), north of Parque Tecnológico de Andalucía, which functions as a large holding tank.

The dam project to regulate the Grande is controversial. It has attracted the interest of institutions such as the city council and the regional government. The interest is not only due to the need for water supply, but also to reduce the flooding of the Guadalhorce in times of 'danas' and storms.

The Cerro Blanco dam

The Cerro Blanco dam, which was to be located between Guaro and Coín, was originally planned within the framework of the repealed national hydrological plan. The strong contestation meant that its design was gradually converted into a large weir of somewhat lesser impact. But this plan did not go ahead either.

In any case, the supply to the city these days revolves around the Aljaima weir and the wells and reservoirs have been left to rest, which always saves pressure on resources.