La Punilla multipurpose scheme

The Punilla multipurpose project will be built on the Ñuble river, about 70 km East of Chillán in the Ñuble region (Central-South of Chile). The main purpose of the scheme is to secure and improve the irrigation in the valley. Additionally, the scheme is equipped with a powerhouse which uses the irrigation water releases to produce power (approx. 500 GWh/yr). The project main features are: - a 32 m high upstream rockfill cofferdam; - two diversion tunnels (D=10 m, L=850 m and 1'015 m) designed for an AEP 1:30 return period flood discharge of 1’800 m³/s; - a 137 m high CFRD (Concrete Face Rockfill Dam) which impounds a 625 Mm³ reservoir; - a gated spillway located on the left bank equipped with three radial gates (BxH=11,0 x 17,5 m) and a chute ending with a ski jump, designed for a discharge of 4'800 m³/s (AEP 1:1’000); - a bottom outlet (B=2.5 m, H=3.5 m, radial gate) located in a diversion tunnel; - a 410 m long penstock in tunnel and buried (D=5.2 to 2.2 m); - an external powerhouse equipped with two 47 MW Francis turbines (Q=2*52 m³/s); - a bottom outlet with two Howell Bunger dissipating valves (D=1.55 m) installed in dissipation chambers; - a substation of 220 kV.
Reference location
Ñuble Region, 400km south of Santiago
Final client
Astaldi SpA
Is Consortium
Start of works date
End of works date
Start of services date
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Preliminary studies; Construction supervision; Civil designs; Electromechanical designs; Special studies