Oct. 25 2013 03:00 AM

Like many older cities, Lancaster’s underground pipes collect both sewage and rainwater. During storms, the Pennsylvania city's sewage-treatment plant can't handle it all, so stormwater and sewage get diverted directly into the Conestoga River, which feeds into Chesapeake Bay. In 2012, about 750 million gallons of stormwater/sewage were allowed to flush into the Conestoga during storm events.

In 1998, the city’s original plan was to build massive storage tanks to store the runoff; instead, the city is two years into a 25-year, $140 million Green Infrastructure Plan. That plan seeks to reduce stormwater runoff through increasing the city's tree canopy, rain gardens, green roofs, porous pavement, rain barrels and other measures.

About 130 projects are underway, complete, or in final design. When that batch is done, by the end of 2014, about 100 million gallons of stormwater will have been captured.