CESI’s project on the Letino Dam for Enel Green Power

CESI was commissioned by Enel Green Power to design the interventions aimed at increasing the discharge capacity and the structural safety of Letino concrete gravity Dam. Letino is a lake in the province of Caserta, in the Campania region, in Italy.    

In order to comply with the requests of the control authority GDD of the Italian Ministry of Infrastructure and Transport, the project included the following hydraulic improvements, which led to triple the discharge capacity and to allow the safe discharge of a 1000 years return period flood:

• Increase of the discharge capacity of the spillway, achieved by lowering the elevation of the sill through its partial demolition and reconstruction
• Realization of a new unloading device, represented by a Middle Level Outlet which crosses the dam

In the same way, structural safety was increased by means of the following measures:

• Injections grouting within the dam body and in foundation rock, with the aim of obtaining a concrete with better mechanic properties
• Rebars grouting in the upper/middle height of the dam, in order to improve its behavior with regard to the seismic load conditions
• Integration of a new drainage system, to reduce the expected uplift pressures at the dam-rock contact interface and within the dam body
• Realization of a curtain grouting in foundation, near the upstream face of the dame, to reduce the seepage from the reservoir
• Remediation of the gunite in correspondence of the upstream face of the dam, in order to improve its impermeability
• Realization of a concrete wall on the crown of the dam, to comply with what the technical legislation foresees in terms of hydraulic freeboard
• Upgrade of the monitoring system

Particular attention was paid to the constructability aspects, due to the large number of activities foreseen in the project and the necessity to plan them in order to maximize safety aspects and minimize times of realization.

Once again, this project showcases CESI’s expertise and commitment to improve the status of Italian dams, facing both problems connected to hydraulic aspects and those related to structural safety.