Improved water supply to the city of Málaga
Casasola Dam stands at a distance of 19 kilometres from Málaga city centre. Its objective is twofold: to eliminate the historic problem of flooding caused by the Campanillas River and to improve Málaga's water supply.
This arch-gravity dam has got a vertical slope upstream and a slope of 0.45 downstream. The upstream face features a three-centre arch whose centres' radii measure 200, 120 and 200 metres. The crown is 240 metres long.
The dam stands 76 metres above its foundations, with its crown at a height of 160 metres. The crown is nine metres wide and accommodates seven metres of road and two one-metre-wide sidewalks that overhang the edges. The volume of water held by the dam at its normal maximum level is 23.64 hm3. The hydrogram of the designed inflow, which is defined as the inflow for a 5,000-year return period, displays a peak flow of 1,745 m3/s. The spillway has a fixed lip and is formed of three separate 20-metre-long spans. The thresholds of the spans on the sides are four metres below the crown (at a height of 156 metres), and the threshold of the central span is 2.5 metres below the thresholds of the lateral spans (at a height of 153.5 metres).
Horizontal operation and inspection galleries were built at three levels: There are two perimeter galleries connected to one another, and there is a vertical shaft housing the material lift together with an accompanying staircase. The first two galleries extend for 35 metres into the abutting rock to facilitate inspection of the rock massif and simplify any future injection work. The intermediate gallery provides access to the bottom draining and water intake chambers.
The total volume of concrete set in the dam was over 200,000 m3, arranged in 16 radial blocks separated by flat joints injected with cement grout after the heat generated by hydration had dissipated, when the space between blocks was at its maximum. Implementation was completed in 36 months, with a monthly maximum production of 15,000 m3.
The dam's foundations were dug out using explosives. In the first few metres of the left-hand side it became necessary to use a backhoe excavator with a hydraulic hammer and lots of popholing, because the massif was heavily fractured on the surface.
The earth was treated with consolidation grouting, a waterproofing wall and a drainage wall, plus supplementary waterproofing and drainage walls on the left-hand side.