5 ms·

Simpler solution would be to bring landfill to raise the ground level of NYC. The first floors of buildings would be converted to extra levels of sub-floors and

by tpurves 10y ago

Simpler solution would be to bring landfill to raise the ground level of NYC. The first floors of buildings would be converted to extra levels of sub-floors and new lobbies/entrances built higher up. Or other buildings could be potentially jacked up to new higher up with new subfloors built inbetween to keep them connected to their old foundations. Or lastly, tear down the old structure and build a new building at the higher level. A lot of cities today are build on top of fill on top of remains of old or ancient cities still below ground.

kbenson 10y ago
I thought I heard once that quite a bit of Manhattan is already landfill (and many of the subfloors are already below sea level). If so, this sounds like it would be the obvious chosen solution.
- czinck 10y ago
  I don't know how much is in total, but the west side was expanded with landfill in the 19th century, and Battery Park City is made entirely of excavated dirt from other construction projects, mainly the Twin Towers.
namlem 10y ago
Why not just build dykes to prevent the flooding in the first place?
- johan_larson 10y ago
  Two problems: the ocean and the Hudson river. The sea approaches NYC from two directions. To the south is the passage between Long Island and Staten Island, and to the east is the passage between the mainland and Long Island. If your goal is to protect all five boroughs of NYC, you have to protect Brooklyn, which faces the open sea directly. So a huge seawall south of of Brooklyn, crossing over to Sandy Hook. That looks to be closer to 10 km straight across. The east is also tricky, because the Bronx reaches so far north and east. Your best bet is probably a dam at Sands Point, but it will have to be a good 4 km long. That should be fun. Finally there is the Hudson river, which flows north to south. You are going to have to divert that somewhere, or it will just pool up in New York harbor until it finds a way to the sea. A Yonkers-New Rochelle canal perhaps? If this is your plan, you will have the gratitude of an entire generation of civil engineers, construction workers, and financiers. Your taxpayers may be less enthusiastic.

by tpurves 10y ago

kbenson 10y ago

I thought I heard once that quite a bit of Manhattan is already landfill (and many of the subfloors are already below sea level). If so, this sounds like it would be the obvious chosen solution.

czinck 10y ago
I don't know how much is in total, but the west side was expanded with landfill in the 19th century, and Battery Park City is made entirely of excavated dirt from other construction projects, mainly the Twin Towers.

namlem 10y ago

Why not just build dykes to prevent the flooding in the first place?

johan_larson 10y ago
Two problems: the ocean and the Hudson river. The sea approaches NYC from two directions. To the south is the passage between Long Island and Staten Island, and to the east is the passage between the mainland and Long Island. If your goal is to protect all five boroughs of NYC, you have to protect Brooklyn, which faces the open sea directly. So a huge seawall south of of Brooklyn, crossing over to Sandy Hook. That looks to be closer to 10 km straight across. The east is also tricky, because the Bronx reaches so far north and east. Your best bet is probably a dam at Sands Point, but it will have to be a good 4 km long. That should be fun. Finally there is the Hudson river, which flows north to south. You are going to have to divert that somewhere, or it will just pool up in New York harbor until it finds a way to the sea. A Yonkers-New Rochelle canal perhaps? If this is your plan, you will have the gratitude of an entire generation of civil engineers, construction workers, and financiers. Your taxpayers may be less enthusiastic.