In 2011, the Department of Environmental Protection (DEP) enforced its Climate Change Program Assessment and Action Plan by researching the potential effects of climate change on the city's water supply. Areas projected to be affected were determined by the DEP's climate change impact scenarios. Funded projects included the Croton Walter Filtration Plant, which opened in 2015 to filter sediments entering the water supply after storms, and the renovation of the Delaware Aqueduct. The DEP took action on its own projects such as improving the sewage system by developing a new stormwater drainage strategy focused on areas threatened by flooding and sewer backups and overflows. There was an overall emphasis on maximizing synergy and minimizing tradeoffs among energy, air, water, land, and climate policies.