The restoration project of the bottom outlet of the Pozzillo Dam is a funded initiative under the National Recovery and Resilience Plan (PNRR). This project aims to enhance the safety and efficiency of Sicilian water infrastructures, ensuring a continuous and secure water service for the local community and the agricultural sector that relies on the dam’s water.

Located in the Municipality of Regalbuto, Enna, the dam required urgent interventions to guarantee its long-term functionality and prevent potential risks related to structural damage and excessive sedimentation.

The main planned works include:

Construction of a New Intake
A new intake will be constructed at an elevation of 333 meters above sea level, connecting to the existing discharge tunnel located at 317 meters above sea level. The tunnel will have an overall length of about 40 meters, with an initial section at a slight incline and a second curvilinear and inclined section, with a diameter varying between 5 and 4.3 meters.

Excavation and Installation of the Interception Shaft
A vertical shaft approximately 39 meters deep will be excavated to connect the new discharge to the existing tunnel, allowing for the interception and diversion of the water flow.

Defense Works for the Channelization of the Riverbed
Support structures using O-Pile technology will be constructed to confine the dredged volume.

Removal of Lake Sediments
Sediments accumulated in the area in front of the new intake will be removed to ensure a continuous and unobstructed water flow.

Consolidation of the Downstream Banks
Works will be carried out to consolidate the banks downstream of the dam to prevent erosion and ensure structural stability.

Maintenance and Cleaning of Existing Structures
Extraordinary maintenance will be performed on the lining of the dam’s bottom outlet tunnel and the access shaft to the maneuvering chamber, including the replacement of hydraulic and electrical systems controlling the new gates.

The main specialized activity necessary for the successful completion of the work is the construction of the support structures for the excavation required to intercept the existing discharge tunnel to which the new bottom outlet will be connected.

The implementation of “O-Pile” (interconnected piles) using the Down-The-Hole (DTH) reverse circulation system with sacrificial shoe represents an advanced method for installing large-diameter piles in difficult geotechnical conditions. This technology is particularly suitable for hard or very compact soils where other drilling methods might be ineffective. This system is especially effective in ensuring the stability of deep excavations and protecting work areas from water infiltration and ground settlements.

The “O-Pile” will be partly constructed from land and partly from the water. To accomplish the latter, a modular floating pontoon will be used.