the new york city green infrastructure plan requires usd billion of investment from the public and private sectors in swales green roofs and other source controls to manage runoff this will have further benefits including cooler temperatures improved air quality more green space lower energy bills and higher property values new york city s green infrastructure plan will change the city form and reduce combined sewer overflows csos by billion gallons per year billion gallons more than the existing grey strategy at a savings of more than usd billion over the year implementation period