An Alternative to the Peripheral Canal

The present mode of water transfer through the Sacramento—San Joaquin Delta is not adequate to meet both future export requirements and maintain desired water quality. A 42-mile long Peripheral Canal that would convey project water around the estuary is favored by state agencies and water contractors but opposed by Northern California water interests who prefer an open water transfer alternative. Water quality control effectiveness was evaluated by means of mathematical models for the present system, the Peripheral Canal, and the alternative. Results of simulations indicated that both the Peripheral Canal and the alternative can control salinity intrusion in the western Delta. The Peripheral Canal was shown to maintain net seaward flow in most channels, while the alternative, because of its through-Delta nature, caused upstream flow in channels leading to export pumps. The alternative was shown to be more effective in maintaining water quality in the central and southern Delta. It was found to be capable of assuring water quality at the export location adequate for intended uses.