Not Quite Waterworld

A good article on life in a city near sea level: “A Fifth of NYC Built on Bygone Water Now at Risk: Study Maps City’s ‘Blue Zones’” BY Samantha Maldonado. The source for much of the research cited in the article is “Blue Zones: Identifying Adaptation Opportunities UsingPast, Present, and Future Flooding in New York City” by Lucinda Royte and Eric Sanderson.

The very short version is that not all of the human interventions in the geography of New York will outlast sea-level rise, and not all were such great ideas to begin with. Some of the problem areas are natural problems: the Rockaway peninsula, for example, is a barrier island that somehow got attached to the mainland (the mainland of Long Island, not the mainland mainland) at one end. It is not particularly surprising that a barrier island is low-lying. Similarly, the west side of Staten Island has always been a swamp, which is why so little of it is heavily built up. The north shore of Jamaica Bay – the south end of Queens and the southeast end of Brooklyn – is also a serious problem.

The poster child for human-made problems is, of course, the landfill areas of Lower Manhattan: everything west of Greenwich Street or east of Pearl Street in the Financial District, and a lot of the land abutting Canal Street. There’s a plan in place to create protection here, but it’s one of those things that won’t be fully tested until it’s needed. That said, the problems aren’t anywhere as bad as they could be, because the local geography has a fair amount of elevation to it. Looking at a topo map of the city here, it’s clear that the heavily-built-up portions of the city are generally high enough to avoid the worst flooding potential. Trinity Church, at Wall Street and Broadway, is at an elevation of 27 feet: a sea-level rise of 25 feet would be a disaster in many more places than New York. The worst of the “Blue Zone” flooding is in low-lying areas that are either near the shore or, because of old landfill/drainage projects, do not drain properly in rainstorms.