Someone has finally found a solution to New York's affordable housing crisis: turn Red Hook and the Columbia Waterfront into a futuristic super-neighborhood with 45 million new square feet of real estate, a new subway line, greenways, a marina for fun waterfront activities, and more. This very realistic proposal from engineering and construction giant AECOM was unveiled on Tuesday at a symposium titled "What Do You Want Your City To Be? Reimagining Southwest Brooklyn" at the Rudin Center for Transportation at NYU. The proposed redevelopment of what would simply be called Southwest Brooklyn would cover 246 acres, an area eight times the size of the Hudson Yards project. That $20 billion project, which was touted as all private development, has of course already consumed hundreds of millions of dollars of city subsidies. Then there's the extension of the 7 train, which took 8 years and cost $2.5 billion.

The Southwest Brooklyn project would create a new arm of the IRT branching off the southern end of the 1 train. The line, which in name would resurrect the dead 9 train (may its memory be a blessing), would run under the harbor to Red Hook and connect with the F/G and R at 4th and 9th. The train would solve a problem that's bedeviled Red Hook since it was guillotined by the BQE—lousy transportation options and both physical and economic isolation from the rest of Brooklyn.

The new square footage—there are also less ambitious proposals for adding 25 and 35 million square feet—would come from high and mid-rise development on land that's currently empty or low density. The city and Port Authority own large swaths of land in the area, including the little-used 80-acre Red Hook Container Terminal, which the PA has considered shutting down, so in theory that could be a starting point for the project. Under the AECOM proposal, the new neighborhood would get 50,000 new units of housing, including 11,000 affordable units (there are currently 3,000 units), and 1.8 extra miles of public waterfront access. AECOM estimates that the project would create around 55,000 jobs.

There would be a pedestrian corridor called the Red Hook Rambla, which hopefully would not be overrun with pickpockets like the original Rambla in Barcelona. In the renderings, the Red Hook Rambla looks a bit like a pedestrian "street" in a fancy mall, just with row houses on either side. Still, the computer-generated kids frolicking about seem happy.

In recognition of the challenges posed to waterfront areas by climate change, the good people at AECOM offer a range of resiliency measures, including building up the coastline, constructing berms and flood barriers, and putting up a flood gate for the Gowanus Canal. But one still questions the wisdom of adding tens of millions of square feet and tens of thousands of housing units in a region of the city that suffered terrible flooding during Hurricane Sandy and has been designated a Zone 1 Hurricane Evacuation area, i.e. at highest risk of flooding during a storm.

Cash rules every redevelopment and urban infrastructure project around us but there's not a lot in the AECOM proposal about cost. The firm estimates that the 25-, 35- and 45-million square foot plans would generate enough revenue to cover "basic development costs." It notes, however, that the most ambitious version would cover only 45 percent of the $3.5 billion subway cost. Theoretically, that would leave a gap of $1.5 billion, but the $3.5 billion price tag seems like a ridiculous lowball, so who knows how large the gap would be.

It's unclear if anyone at the Port Authority or the de Blasio administration is seriously considering any of this, but AECOM is a major force in NYC development, and it's worth noting that AECOM's senior vice president, Chris Ward, was formerly a top executive at the Port Authority. "We have to recognize that growth is necessary to create a waterfront that people can use, affordable housing and a mass-transit connection to a neighborhood where one doesn't exist," Ward tells Crain's.

You can check out the whole plan here.