Beginning of the Project and the First Royal Visit
A sad event such as a big flood in Málaga in 1907 was the opportunity for making a reservoir, which had been wished for since the Hydroelectric Company El Chorro was created. It was meant to control the river flow of the Guadalhorce. This happening was the reason for the first visit to the city by Algonso XIII. He came with the Prime Minister Mr Maura and the Minister of Public Works Mr Gasset. The result of the visit was creation of the Division of Hydraulic Company in Southern Spain, whose main purpose was to perform works that were needed to protect inhabitants, create irrigation channels and control water flow in the area. One of the engineers that were hired for this job was Mr Jiménez Lombardo, who, among other projects, carried out the first dam on the River Turón.
To this positive state of affairs we could add the fact that the Hydroelectric Power Company was working well. Later on, this made it possible for its Sevillian engineer, Rafael Benjumea (1876-1952), the driving force behind the project, to build a big dam for watering Hoya de Málaga, a big and fertile plain in the Guadalhorce (wheat in Arabic) River Valley. This building project had an additional aim; this is to control the amount of river flow that was coming to the Hydroelectric Power Station El Chorro, which used to depend on seasonal rainfall.
After the project was finished by Jimenez Lombardo in 1913, a geological survey done by a civil engineer, Mr Gutiérrez de Gándara, motivated the relocation of the dam to a lower place. A year later, in August 1914, ‘La Gaceta de Madrid’, a public newspaper, officially approved works on El Chorro Reservoir. The original project forecast the building of a dam at an altitude of 35 metres and a reservoir of 27 cubic hectometres water collection following the 1911 Gasset Act.
From financial point of view, the project was funded by the State (that covered half of the costs, and invested 40% more before the works started) and the Hydroelectric Company El Chorro, which was only supposed to pay 10% of the price.
The works were developing at a fast pace, and were watchfully supervised by Benjumea, who acted as an extraordinary constructor and planner. Some five kilometres away from the dam, he built the cement factory Pórtland in order to assure material supply that was in danger of cutting off due to World War I.
The Role of the Railway and Electric Machines
As there were no roads, all the material for works was moved by trains to the building site. For this purpose, a halt, named ‘El Coscojal, was built between the train stops Gobantes and El Chorro. From that point to the quarry, a small train that was meant to transfer material to the dam was going along the branch made for this purpose. At first, single file of donkeys was used for stocking sand, but, as soon as parts of reservoirs were filled with water, they started to use motor barges to bring sand from some of the close dry river beds. A small settlement for six hundred workers on the dam was built. There was also a company shop that sold cheap essential products.
Nevertheless, maybe the most innovative thing was the modern electric machinery that was used. It consisted of water extraction pumps, concrete mixers, cranes, capstans, pneumatic drills, which would get electricity through a particular grid that was extended from the Hydroelectric Power Station El Chorro to the precipices where the dam was being built. As we have already said, there was a lack of cement at the time due to World War I, so it was necessary to control its use. Therefore, after 20 metres of foundations below the river bed were laid, huge dry-stone pillars were built with cranes on them all around the building site in order to move and position big stone blocks more easily. These stones used to be placed on the fresh concrete so they would stick well.
The works on the upstream part of the dam and the slopes were faster so that the dam would be used for dumping waste material. The parameter of the dam which was downstream was made of reddish stone that formed aesthetically pleasing dry-stone walls covered by concrete.
The New Dam
Little time after the works on the project began, this one was rewritten. The height of the dam was increased to 50 metres and the reservoir’s capacity was 80 cubic hectometres. Having the new project been approved, the works continued at a fast pace in a rugged but beautiful scenery and without foreign interfering in spite of all the difficulties they had to get machines and spare parts from the more developed countries in Europe during the First World War.
Finally, the works were finished, and King Alfonso XII came to place the last stone of this enormous dam during torrential rain on 21st May 1921. This event was made public in the newspaper ‘Blanco y Negro’ (Black and White). Interestingly, he used an ashlar similar to those used by Romans’ engineers in their works of architecture and engineering. Elegant stone chair and table were used to give splendour to a solemn royal opening ceremony.