'Sponge cities' can cope with increased water levels, and New York City is working to become more porous. New York City is preparing for both chronic storm eventsthese cloudburst events that we see occurring more and more frequentlyas well as extreme storm events like Ida, says Jennifer Cherrier, a professor of earth and environmental sciences at Brooklyn College. About 39% of the city is already green space like parks, tree-lined streets, and waterfront areas. They help absorb floodwater andhave high amounts of sandy soil to absorb water better than clay-based soil. Closer analysis will enable the city to plan where to strategically green up, including the expensive upgrading of its very old sewage system.