Дамба «Вал Дам» (г. Сарагоса)

This huge dam, operating since 2001, is located in the River Val valley, almost at the mouth of the River Queiles and just a few meters upstream from the town of Los Fayos (Zaragoza). It was the first project undertaken under the "Aragon Water Agreement", as a storage dam to regulate water supplies and irrigate the areas of the Queiles valley that only received the necessary water in exceptionally rainy seasons. The works included an inter-basin diversion from the deep Queiles River to the Val River, which runs through a more level valley and is better suited for the construction of a dam. Thus, one of the rivers provides the water, whilst the other provides the valley in which to store it.

The reservoir has a useful capacity of 24 hm³; it guarantees water supply to 51,300 inhabitants and the irrigation of 12,855 Ha; it laminates the banks of the Queiles River, thereby protecting the Los Fayos village, and provides new surroundings for tourist and leisure purposes.

The dam was built in roller-compacted concrete, giving the downstream face its characteristic steps, reaching an impressive height of 90 m and a crest length of 400 m. The spillway 20 m wide and located at the centre of the dam, is also stepped; at the foot is the stilling basin, 60 m. long. Preliminary studies were conducted on the hydraulic operation of the spillway/stilling basin lock, using a scale model at the CEDEX laboratory, in Madrid. The bottom outlets consists of two conduits, 1.2 m wide, regulated by double gates, opening onto the stilling basin itself, and the irrigation points, located on the left margin, consist of two conduit, 0.9 m wide, also closed with double gates.

To enable the inter-basin diversion from the Queiles River, the Val reservoir was fitted with a diversion dam 13 m high and 70 m long, with a channel for river water supply regulated with gates.

In relation to the body of the dam, the most representative works figures includes the use of 740,000 m³ of concrete and 1,800,000 tonnes of aggregates for manufacturing purposes; the excavation of 597,000 m³; the construction of galleries 900 m long; or the execution of 23,000 m drills for drainage and injection. Amongst the figures located outside the dam, 12,000 m³ were excavated in tunnels, 50,000 m³ of concrete was used, a 2.4 km access road was built and paved, 16.3 km of service paths were provided, 6.5 km of suspended high-voltage line, 640,000 m³ of excavation work in earth and rock, and 250 ha were cleared at the reservoir basin, amongst others.

Apart from the body of the dam, control, administration and surveillance offices were built; equipment was installed; the crest was reinforced; the mouths of the drains were executed, including the outlet channel, lighting and finishings, adjustments, hydro-seeding and other steps required for the perfect finish of this unique construction.

During the works, the proximity of the town of Los Fayos was taken into account, and many steps were taken to reduce any possible disturbance; an access road was built to avoid heavy traffic in the town and the works facilities (storage of aggregates, grinding and classification plant, regulated concrete plant and concrete transportation components) were located upstream from the dam.