The California Water Fix, the planning document from the CalFed process, mandates that some method of correcting the salt water influx to the Delta must be found. California water officials believe that the solution would be a series of pumps that would deliver fresh water from above the point where water is now extracted. The tunnel from the pumps would carry the water 35 miles away from the Delta to the San Joaquin Valley system. The federal agencies in charge have said in this draft proposal that the building of the tunnel will not imperil endangered species like the Delta Smelt and Coho salmon. The proposal pits fishermen, environmental groups, delta farmers and others, that worry it will make it easier to take Northern California water against Southern California water interests, farmers and water agencies.
Even with the approval from the federal government there remain many hurdles. One of the issues if the Southern California water agencies can convince their customers that the cost is worth the value to be gained. The increasing uncertainty of water delivery, due to potential damage from earthquakes and increasing pressure from endangered species, with current infrastructure is one reason the state has continued to push for the tunnels as a solution.