California has one of the most ambitious and highly engineered water delivery systems on the planet, and it’s being eyed for a new extension. The Delta Conveyance Project is Governor Gavin Newsom’s proposal for a 45-mile underground tube that would tap fresh water from its source in the north and carry it beneath a vast wetland to users in the south. The Delta is the exchange point for half of California’s water supply, and the tunnel is an extension of the State Water Project, which was built in the 1960s. It’s a 700-mile maze of aqueducts and canals that sends Delta water from the Bay Area down to farms and cities in Central and Southern California. This is a local story about a global issue, the future of water. In a three-part series of field reports and podcasts, Bay City News reporter Ruth Dusseault looks at the tunnel’s stakeholders, its engineering challenges, and explores the preindustrial Delta and its future restoration.