Early 1900s hydroelectric development in the upper San Joaquin River basin was not limited to Southern California Edison. In 1910, the San Joaquin Electric Company built a dam on Willow Creek, a tributary of the San Joaquin River, forming Bass Lake as part of the Crane Valley hydroelectric project. Water from Bass Lake was diverted to a powerhouse on the San Joaquin River beginning in 1917, and two more powerhouses were added in 1919, increasing the total generating capacity to about 28 MW. The Crane Valley project and San Joaquin Electric was purchased by San Joaquin Light and Power Company in 1909, which was in turn purchased by Pacific Gas and Electric Company (PG&E) in 1936. In 1920, Kerckhoff Dam was completed on the San Joaquin River about southwest of Big Creek as part of PG&E's Kerckhoff hydroelectric project. The dam initially operated with a capacity of 38 MW in the Kerckhoff No. 1 Powerhouse on Millerton Lake. In 1983, the 155 MW Kerckhoff No. 2 Powerhouse was added, bringing the total capacity to 193 MW.