New York is turning to a more natural form of water management known as blue belts.

Instead of building pipes, ditches and dams, the city is increasingly relying on a network of ponds, streams and wetlands to absorb the water -- like this installation on Staten Island. These natural features are often cheaper than hard infrastructure, and can also function as recreation areas.

Much of New York City's environmental planning -- both flood and otherwise -- has been consolidated around a concept called PlaNYC. Launched in 2007, experts praise PlaNYC for its data-driven and holistic approach to environmental management.

"It's one of the best plans we've seen out there," said Fred Ellermeier, vice president of smart integrated infrastructure at Black and Veatch, a global engineering and construction firm. "New York has provided a template for other cities."