Angeles Tunnel

[4][5] The tunnel also supplies water to the adjacent Castaic Power Plant, a pumped-storage hydroelectricity generation facility.

[3][6][7] To facilitate power generation, the tunnel's flow is bidirectional.

[6][8][9] The water is then stored in the Elderberry Forebay, adjacent to Castaic Lake.

During off-peak hours, water is pumped uphill through the tunnel in the opposite direction from Elderberry Forebay and returned to Pyramid Lake.

[6] This operation reduces the energy cost of moving water along the California Aqueduct.