It is a cooperative venture between the LADWP and the Department of Water Resources of the State of California.

From here it flows through a permanent pipeline waterway to Warne Power Plant, which is located at the inlet to Pyramid Lake.

The plant rating is 1,247,000 kilowatts (Nominal installed capacity is higher (over 1,500 MW), however when all main units are operating at full load in generate, they are de-rated by friction losses from the water flow in the Angeles Tunnel).

[3] Visible from Templin Highway and normally mistaken for a water tank, the surge chamber sits at the south end of the Angeles Tunnel.

[4] The chamber is there to relieve excess pressure in the tunnel and penstocks if the plant were to experience an emergency shutdown of its generators.

This assures the availability of at least 10,000 acre-feet (12,000,000 m3) of water which can be pumped back to Pyramid Lake by the use of off peak energy when economical to do so.

The water which normally flows through the West Branch of the State Aqueduct during off peak periods, is stored in the higher level Pyramid Lake.