City Limits: The water first rose up out of the streets in Coney Island, recalls Ida Sanoff, sometime last summer.

“I was standing last summer on the corner of Mermaid Avenue and I think West 19th Street, and it hadn’t rained in several days, and the entire intersection was a lake,” she recalls. “And all of a sudden as I watched, the water started going down.” The next day at the same time, the same thing happened. “Sure enough, I pulled out my phone — the tide was going out.”

The phenomenon is known as “blue-sky flooding,” and occurs when rising tides reach the level of sewer outflows, sending seawater (and sewer water) backing up through storm drains. It’s become increasingly common along the Florida shore and other coastal cities, but until now hadn’t been a part of Coney Island life.

Meanwhile, a little less then a mile west down the peninsula, developer John Catsimatidis’ soon-to-open 21-story luxury rental project Ocean Dreams towers over the neighboring public housing blocks. And Sanoff’s puddled intersection itself is in the process of being torn up — ironically — for a sewer project to prepare the way for a massive 1,000-unit residential complex that is about to rise across the street from the Brooklyn Cyclones’ ballpark.

That juxtaposition — of a city with more residents at risk from sea level rise than any other in the U.S., yet still building new waterfront construction at a breakneck pace — has some New Yorkers wondering if two of the de Blasio administration’s signature issues, housing construction and green planning, are on a collision course along the city’s 520 miles of shoreline. The mayor’s office says it can do both, pointing to billions of dollars being spent to mitigate the impact of rising sea levels. Read more>>