Upgrade of the under sluice in the Pedrezuela dam in Madrid

Constructed in 1968 to regulate water in the course of the river Guadalix in the north of the Community of Madrid, the Pedrezuela dam is a hydraulic infrastructure measuring 52 m in height. Despite the drainage valves causing the lowest possible impact on the land, intervention was required to solve two problems. 
 
Firstly, the original orientation of the valves was causing destabilisation of the slope of the access road and, secondly, the cofferdam pen stocks located upstream were causing leakage downstream due to their poor condition. 
 
This intervention offered a comprehensive solution for the dam and its surroundings. Firstly, the hollow jet Howell-Bunger discharge valves were reoriented so that the water impacts with the ground in the lowest area of the two slopes on both banks, thus avoiding the destabilisation of the slopes due to scour. 

 

Secondly, there are downstream Howell-Bunger valves which, although they can shut off the flow, are not expressly designed for this purpose, but rather to expel the stream in a specific way. Two new downstream pen stocks with gate valves with a diameter of 1800 mm were installed. This makes it possible to completely shut off the sluices and plug the leakage of the upstream pen stocks. Moreover, this solution allows the hollow jet valves to be open without being operational, which facilitates maintenance. 
 
The work was completed with the construction of a new control house for the under sluices.