Cities find green ways to reduce storm floods

NEW ORLEANS (AP) — For more than a century, New Orleans has depended on canals and pumps to get rid of stormwater in a city where about half the land is below sea level.

Now the bustling Mississippi River port that expanded by filling in wetlands is spending $270 million to create spaces for rainwater, such as the water garden planned on a 25-acre site provided by nuns who lived there before Hurricane Katrina.

The city is also installing underground holding tanks, porous pavement and other measures to reduce storm flooding and stress on huge pumps built in the 1910s.

“We’ve got a scenario for everything,” said Mary Kincaid, the city’s chief resilience officer.

Tropical storms can dump amazing amounts of rain, and hurricane season starts June 1. But smaller storms can also overwhelm storm drainage.

So cities around the country are taking creative steps to tame stormwater as climate change increases the number and intensity of hurricanes and other storms. Rising sea levels also elevate groundwater levels in coastal communities, reducing the soil’s ability to absorb rain.

“Stormwater runoff is one of the fastest growing sources of pollution,” the federal Environmental Protection Agency states on its website. “When rain hits rooftops, parking lots and roads instead of wetlands, forests and grasslands, it tends to run into storm drains that are directly connected to our waterways.”

In Pittsburgh, as in about 850 other areas where storm drains tie into sewer lines, sewage sometimes backs up into basements, floods streets and pours into rivers.

To attack one neighborhood's problem, the Pittsburgh Water & Sewer Authority installed underground tanks and planted grasses and other native plants near a hilltop as a water-absorbent “bioswale.”

In New...