Tensions over unanswered questions on how California’s largest water district might help pay for two proposed giant water tunnels boiled over into cursing at a meeting of the water district’s board members. Gov. Jerry Brown’s administration is pushing to get financing and regulatory approval squared away for the $15.7 billion water tunnels. The 35-mile-long tunnels would divert water from Northern California’s Sacramento River before it reaches the San Francisco Bay, delivering the water to Central and Southern California cities and farms.