A single rainstorm can whisk 10,000 tons of dirt and grit and millions of pounds of toxics and nutrient pollution into the Chesapeake Bay. Officials from Maryland, Pennsylvania, Virginia, and the District of Columbia are unveiling plans today to rein in rain-related pollution problems, in the first major restoration effort they’ve announced since pledging well over a year ago to take action on the issue. Runoff is polluting nearly 1,600 miles of streams and wreaking havoc on thousands of acres of habitat for crabs and fish. The officials hope to encourage new construction strategies in the region, so that future developments leave natural drainage systems in place to absorb rainwater on site. Currently, rainwater is flushed into nearby creeks and sewage overflow systems.