A project that might make much of the Sacramento River vanish into three giant holes in the ground will not jeopardize the waterway’s ailing salmon and smelt populations, according to new analyses from the federal government. The Delta Tunnels – which would be 35 miles long, cost at least $15 billion to build and be capable of sending much of the state’s biggest river to farmers and urban users – received a stubby thumbs-up from the Trump administration on June 26.