SACRAMENTO, Calif. (AP) – A congressman wants to ban environmental lawsuits challenging a plan to build two gigantic tunnels to divert water from Northern to Southern California. The Sacramento Bee says Republican Rep. Ken Calvert inserted the ban in a proposed Interior Department spending bill released Tuesday. If Congress approves the provision, it might gut some existing lawsuits and bar future ones challenging environmental impact studies. The $17-billion WaterFix project would create two tunnels to carry water from the Sacramento River southward to the San Francisco Bay Area, farm-rich Central Valley and Southern California urban areas. Critics who’ve filed a dozen lawsuits over the years say it could be an environmental disaster and they accuse Calvert of trying to do silence opposition. But Calvert says after a decade of studies, enough is enough.