in 1961, ground was broken on oroville dam, and in 1963, work began on the california aqueduct and san luis reservoir. the first deliveries to the bay area were made in 1962, and water reached the san joaquin valley by 1968. due to concerns over the fault-ridden geography of the tehachapi mountains, the tunnel plan was scrapped; the water would have to be pumped over the mountains' crest. in 1973, the pumps and the east and west branches of the aqueduct were completed, and the first water was delivered to southern california. a peripheral canal, which would have carried swp water around the vulnerable and ecologically sensitive sacramento–san joaquin river delta, was rejected in 1982 due to environmental concerns. the coastal branch, which delivers water to coastal central california, was completed in 1997.