Montejaque dam water levels drop 20 metres as subsoil absorbs record flood
A century after its failed launch, the Los Caballeros dam in Malaga province has successfully managed its first major flood event without incident
The Los Caballeros dam in Montejaque (Malaga province) challenged its nickname - 'the ghost dam' - on 13 February, when it reached its highest level in history, within 30 centimetres of its absolute capacity.
Thanks to the efficiency of the spillway siphons, it started to release water. At the same time, the subsoil has been absorbing water thanks to the good weather.
On 6 March, the level had dropped to ten metres below the limit. On 24 March, it had dropped another ten metres. This would mean that there are still some 50 metres to go, bearing in mind that the level above the riverbed is 74 metres (above the foundations it is 84).
The dam, therefore, poses no threat to the nearby population and is becoming an increasingly popular place to visit.
Failure to seal the dam
A century later, the vaulted, double-curved wall, which is anchored to the two hills (Tavizna and Taviznilla) by means of abutments, is in remarkable condition. The dam is very slender at the top - three metres, compared to 17 above the foundations. Its average thickness is 6.7 metres.
It was built in 36 weeks, in 24-hour shifts. It was the work of Swiss engineer Henri Edwuard Gruner, who had gained experience back home.
Failures in the geological calculations, however, have left the dam unable to hold water in a stable and safe manner, despite attempts to seal it, even from inside the Cueva del Gato.
Historic release of water
On 13 February, the eight kilometres of galleries in the Hundidero-Gato cave complex acted as a flood control system. Although the Guadiaro flowed down towards Estación de Benaoján, Jimera de Líbar and Cortes de la Frontera, there were no incidents.
According to estimates, the siphons released between five and six million cubic metres of the nearly 36 for which Los Caballeros was designed. It was a happy ending to a very uncertain situation created around a system that had never been tested.
The file for the termination of the concession to produce electricity, something that never happened, must determine how technically this dam should be deactivated.
