TRAYNOR, J. In 1913, the defendant city of Los Angeles completed its aqueduct to the Owens River Valley and, from 1919 to 1937, diverted into it virtually all the flow of the Owens River, which formerly emptied into Owens Lake, a body of salt water without outlet. As a result the lake dried up and its subsurface became a crystalline cake impregnated with brines containing valuable chemicals. On the shores of the dry lake plaintiff had two plants to which brines pumped from wells on the bed of the lake were piped for the production of soda products. Plaintiff acquired the older of the two plants in 1932, when it leased mineral rights in the lake from the State of California. Plaintiff subsequently extended its pipe lines several miles farther along the bed of the lake, drilled wells, and installed pumps and brine heaters, acquiring the necessary leases and rights of way from the state. The brines thus made available were of higher alkalinity and therefore of greater value than those previously obtained. To improve its efficiency in extracting chemicals from the brines so as to increase production, plaintiff built a new plant and adopted a new process.
