Two tunnels, one or none? The question continues to swirl around plans to perform major surgery on the sickly heart of California’s water system. Confronted with a shortage of funding, state officials announced last month that they would move ahead with the construction of one giant water tunnel under the Sacramento-San Joaquin Delta rather than two. But the announcement did little to settle the fate of the project, which Gov. Jerry Brown’s administration considers vital to sustaining water deliveries to one of the country’s richest agricultural regions and the urban sprawl of Southern California.