Floating megacity designed for the banks of the Mississippi

Arcologies, which are essentially entire cities crammed into a single high population density megastructure, are still the realm of science fiction – or games such as Simcity. But with the rebuilding of New Orleans after Hurricane Katrina ongoing, a group of designers have come up with the proposal for just such a structure designed to sit on the bank of the Mississippi. Called the New Orleans Arcology Habitat (NOAH), the structure would house 40,000 residents along with all services and amenities that would allow them to live their entire lives within its walls if they so desired.

With much of New Orleans built below sea level and the city prone to extreme winds, NOAH’s designers chose to go with the concept of a floating structure whose open triangular frame shape is designed to dissipate severe winds by allowing weather to blow through the structure in any direction with a minimum of massing interference. The structure’s outer edges are also curved and tilted to further dissipate wind loads, while both curved and flat surfaces would be outfitted with secured sliding hurricane panels to form a protective exterior barrier.

While the 1,200 ft (366 m) structure is actually designed to float, it wouldn’t be set adrift on the Mississippi. Instead a water filled basin around 1,200 ft (366 m) in diameter and 250 ft (76 m) deep would be constructed on the bank of the Mississippi. The basin would partially be carved out of the existing land and also extended out into the river.

he actual foundation of the NOAH superstructure would then float within the basin thanks to its multi-cavity “hull” consisting of high strength concrete cells that form a matrix of approximately 40 x 40 cells. This matrix is designed to give the structure buoyancy and form the frame for the steel framed superstructure. The designers estimate that structure will draft 180 ft (55 m) within the water-filled basin, allowing for a minimum 50 ft (15 m) space between the floor of the basin and the floor of NOAH’s foundations.

Inside, “sky gardens” will be placed every 30 floors within the three main towers to act as community spaces. Designed as an all-pedestrian environment, only select horizontal areas will be fitted with moving walkways and/or electric train carriers, while vertical commuters will travel via a series of local and express elevators.

With no need for cars – although a parking garage to house 8,000 cars would be built within the foundations – NOAH is designed to be carbon neutral with solar array banding panels, wind turbines, river-based turbines, passive glazing system, sky garden heating/cooling vents, grey water treatment and fresh water recovery and storage systems.

NOAH’s estimated 30 million-square-footage (2.8 million m2) would be broken up into 20,000 residential units, three hotels, 1,500 time share units, three casinos, 1 million square feet of commercial space, 8,000 car garage, 100,000 square foot district school system, 50,000 square foot public works, 50,000 square foot administrative offices and 20,000 square foot district health care facility.

The NOAH design team sees the structure as a viable plan, not only for New Orleans but for any coastal urban area. And while there are many advantages to the concept of arcologies, they remain very much on the drawing-board at this stage.