Shorelines in South Bay San Diego will never be fully immune from the sewage and chemical pollution that flows north from Mexico over the border through canyons and the Tijuana River. However, beach closures triggered by contaminated stormwater and Tijuana’s leaky sewer system can be dramatically reduced — from more than a hundred days a year to perhaps a just few dozen. That was the message last week from President Trump’s U.S. Environmental Protection Agency, which released the most comprehensive blueprint to date for addressing water pollution that fouls shorelines in Imperial Beach more than a third of the year on average.