FCC Construcción has completed the reservoir of Castrovido, Burgos. He built reservoir has as objective river regulation Arlanza, thus pursuing the protection of populations riverside in front of floods and damming volumes needed for use them for urban supply, ecological purposes and irrigation.

The project consisted of the execution of a main gravity dam with a plant straight, built with vibrated mass concrete. The crowning height is 1,048
meters above sea level and has a maximum height above foundations of 95 meters, consisting of a length of 534 meters.

The dam has two spillways at different heights. Both spillways discharge their flows over a buffer bowl existing in the central part of the dam foot.

It has two conduits for bottom drains that have a double gate each one as well as two semi-cylindrical intake towers: one for a hydroelectric plant; another as a water intake. For the auscultation, control and maintenance of the body of dam and its foundation four levels of inspection galleries have been built horizontal, two perimeter galleries, accessed through galleries cross-sections to one side and the other of the downstream dam and giving access to the chambers valves, in addition to housing various elements for the auscultation of the dam; and one drainage control gallery.

In turn, FCC Construcción has developed a "Los Vados" tail dam consisting of in a cylindrical vault 12 meters high and laterally embedded in two stirrups-gravity buttresses, and with two closing wings against the slopes.

Among those services that are affected by the construction of the reservoir, find the road section of the CL-117 Comarcal road that runs between Castrillo de la Reina and Palacios de la Sierra. The intersection project of access to the industrial park of Palacios de la Sierra as well as the extension of the BUV-8226. A town of the Administration has been built to cover the need for permanent residence in the event of alert and emergency situations that could be produced in a timely manner, and by the continuous control and surveillance of all systems and facilities that the correct exploitation of this type of works requires. It includes the execution of electrical lines for the electrical supply to the different mechanisms of operation and services of both dams and the town of the administration.

It is a project in which the aspects have been taken care of to the maximum environmental aspects of the ecosystem: it has been recovered, restored and integrated the landscape is affected by the project; the river basin has been reforested Arlanza by planting conifers as well as the tail of the reservoir. They havecreated four artificial islands in the area of the tail reservoir as well as a beach in the same area. The tail reservoir will be dedicated to sports, ecological and cultural uses: jetty, viewpoints, bird observatory, playground, parking, conditioning of areas for sport fishing, picnic areas and information booth.