New Orleans, Floating

The City of New Orleans has a close relationship with water. It borders Lake Pontchartrain, Lake Borne, and The Mississippi River with an intricate network of canals, lakes, swamps, and marshes that feed into the Gulf of Mexico. New Orleans could be referred to as a water city. The Port of New Orleans has one of the most busiest port complexes in the world. The 14,500-mile inland waterway is very active with marine traffic.

The chief sectors of New Orleans economy are: offshore drilling, shipping, shipbuilding, aerospace manufacturing, and tourism which drive the economy for a profitable side of its relationship with water. The downside of this water relationship is its vulnerable low-lying landscape and weather patterns. A typical cross section view of New Orleans topography shows the grade that resembles a bowl-like land surface area indented in water. The city is situated below thw water line of the Mississippi River and Lake Pontchartrain. Weather is a constant threat to the city with its busy hurricane season and it being 51% below sea level is cause for serious concern.

Studies from The Army Corps of Engineers and the American Society of Professioal Engineers have shown severe cases of coastal erosion. The rising sealeves brought on by global warming have been calculated at a rise of 12 inches per century.In the case of New Orleans careful attention must be paid to geological data, weather history, forecasting and researching rising water levels before any kind of new programs or structures are planned.

There are solutions and projects in planning.Actor Brad Pitt’s Make it Right proposal is to rebuild the lower 9th Ward with affordable, sustainable homes for working families. The homes are built on concrete piers approximately 8 to 10 feet above grade.

The Netherlands are also a water city under the constant threat of flooding as 3/4 of its land mass is below sea level.Architects Herman Hertzberger and Koen Ulthius have taken a different approach to flooding by working with water instead of against it. Herman Hertzberger built his first floating house in 1986. His “Watervilla” is a home that sits on a steel floatation system with a foam-filled concrete box below that can be rotated with 2 steering wheels.

Koen Olthius’ firm Waterstudio believes “let the water in and even make freinds with it” instead of constantly pumping water. Waterstudio has pattened technology to create floating foundations with foam and concrete. The piles are sunk in the ground and the foundations move up and down with the water levels. This technology allows for larger structures than a typical houseboat in Amsterdam. Elizabeth English is affiliated with Louisiana State University is also using floating foundations in retrofitting shot gun houses in New Orleans.

With this technology developed by the Dutch, its floatation blocks are made of an expanded polystyrene material also known as styrofoam, which is a deceptively strong material commonly used in concrete foundations.

Floating infrastructure is also implemented. There are currently 4 floating airports in Japan. Other stetigies in flood protection are coastal barriers. The Watergates in Japan are gates that are lowered in the event of a storm. The Maeslant Barrier in Holland closes with 2 clam shell barriers that meet in the center. The Thames Barrier is the second largest barrier in the world located downstream from London. It is a unique machine in which a piston pulls a rocker arm that rotates the barriers like a barrel.New building technologies and materials are constantly developed.New Technology and communication makes for an accelerated pace of research and design.

The question that comes to mind is: How can we rebuild The City of New Orleans and protect it from potential disasters with innovative design and construction methods? Is there a way that the two can co-exist in harmony with respect to nature and New Orleans itself?

KEY: LOWEST TO HIGHEST ELEVATION:DARKEST TO LIGHTEST

-4.00 to -1.25

-1.25 to -.50-.50 to 0

0 to .51 to 2

2 to 33 to 4

4 to 8.5

New Orleans Elevations

City of New Orleans Ground Elevationsfrom Canal Street at the Mississippi River

to Lake Pontchartrain

Canal St.at River

St. LouisCathedral

Esplanade at St Paul

Derbigny at I-10

Gentilly Blvd. at Allen

Dillard University Campus

St. Anthony at Wildair Dr.

Wainright Dr.at L.C. Simon

UNO Side ofWainright Dr.

30

20

10

0

-10

-20 -20

-10

0

10

30

20

Floodwalls along Mississippi River

23 feet18 ft Project flowline

Avg. Annual Highwater 14 ft

MississippiRiver Bank

GentillyRidge

AB

HurricaneProtection Levee

& Floodwall

17.5 feet

SPH Design Elevation 11.5 ft

Normal Lake 1.0 ft Level

Lake Ponchartrain

A

B

NewOrleans

LakePontchartrain

The City of New Orleans is 51% below Sea Level with a mean elevation of 5 feet abovesealevel. The section above shows New Orleans in a “bowl-like” land surface indented in water with the neighboring Lake Pontchartrain and Mississippi River protected by natural levees and man made seawalls.

TOPOGRAPHY AND SOIL CONDITIONS

Lake Pontchartrain

Block Diagram of the City of New Orleans

TOPOGRAPHY AND SOIL CONDITIONS

Metairie-Gentilly Ridge Distributary

Sand

Swamp

Highly Organic Clays & Peat

Organic and High water content clays

Clay

Second Pleistocene Formation

New Orleans

First Pleistocene

Natural Levee

Marsh

Interdistributary Bay

Delta Front DepositsProDelta Deposits

Shelf Deposits

Fresh Marsh

Levee ChannelLeft: Block Diagram of New Orleans The Metaire Distributaries Channel extends to a depth of 50 feet. Note faults below lake Pontchartrain.

Right:Block Diagram shows underlying sediments, overlain peaty soils.

Soil conditions of New Orleans are of a soft compressible material which sometimes consists of cypress deposits.

Levee wall with concrete wall

Levees of New Orleans

Natural levee

Concrete wall

Sheet piling

Section of a typical levee wall in New Orleans

Levee failures partly were due to overtopping Coastal erosion and poor foundation materials. Sample of material is made up of several layers of cypress swamp deposits, clays, and shells. The sheeting as shown above was did not reach a proper depth. New seawalls are being installed with increased heights and foundations ofdepths to 100 feet below grade.

CREOLE COTTAGE 1790-1850

Scattered throughout New Orleans, The Creole Cottage are foundPredominantly the French Quarter, the surrounding areas of Faubourg Marigny, the Bywater and Esplanade Ridge.The Creole Cottage is a one story house set at at ground level with asteep roof pitch. It is set close to the property line and has a symetricalfront exterior with four openings.

NEW ORLEANS ARCHITECTURAL STYLES

Wood /StuccoFacade

Steep Roof Pitch

Set at Ground LevelSet Close to

Property Line

AMERICAN TOWNHOUSE 1820-1850Located In Central Business District, Lower Garden District, Faubourg Marigny and The French Quarter. American Townhouses are typically narrow, three storieswith a stucco or brick facade. The second floor usually features abalcony.

Narrow 3 story wood framed w/ brick or stucco facade

Front exterior close to property line

Steeply pitched roof(sometimes) w/ severaldormers

SHOTGUN HOUSE 1850-1910

The shotgun house is a narrow residence approximatley12 Ft wide situated on block piers about 2 to 3 feet above grade. They can be found throughout new orleans and many other southern towns. It’s name comes from aligned openings. One can “fire a shot gun” through the front door and out of the back door without hitting a wall. It was also said that the original shotgun houses were built from the wood from “shotgun shell crates”.

Wood frame w/ wood cladding

symetrical 4 opening in front elevation

Aligned openings for ventiliation

DOUBLE-GALLERY HOUSE1820-1850The Double Gallery House was built as a variation of The American Townhouse. It features two covered galleries which are framed with a colonade supporting entablature with an asymetrical arrangement of its openings. The Double Gallery house is loacated in the Garden District, Uptown, and the Esplanade Ridge.

MAKE IT RIGHTActor Brad Pitt’s proposal for rebuilding the Lower 9th Ward with affordable, sustainable homes. Make it Right has completed nearly 50 homes and broughtover 200 home people back to the Lower 9th Ward. More than 150 new homes are planned in the lower 9th Ward.

FLOOD CONTROL

Concrete piers 8 to 10 feetabove grade

Solar panels

Many Shotgun houses are being retrofitted with the Base Flood Elevation(BFE) system. The structure is situated at grade with new telescopic posts and beams that rise with flood water levels. These structures elevate asmuch as 12 to 15 feet. The renovation is concealed in the foundation as the original traditionalarchitecture is preserved.

Water level at 2’-0 above gradeShot gun house at dry conditions

Block piers on original shotgun houses

New Beams & piles for “lifting” house as water level rises.

RENOVATING HOMES WITH BUOYANT FOUDATIONS

Water level at 4’-0 above grade Water level at 8’-0 above grade

WATERVILLAArchitect Herman Hertzberger’s “Watervilla” floats on a concrete box below. It is typically moored to the shore on posts driven into the ground. Utilities for the home are routed to the home with flexible pipes. The structure rises and descends with the water levels. The home can be rotated at any angle. Waterstudio has built 25units. Floating architecture has many possibilities for land starved cities as well as flood prevention.

THE CITIDELThe Netherlands have similar flooding conditions as New Orleans. Half of the country sits at below sealevel.Architects Koen Ulthius and Herman Hertzberger are taking a different approach to flooding problems by designing structures that float on flood waters.

FLOATING INFRASTRUCTURE

Japan has 4 floating Airports

Kawai International Airport

New Kitakyushu Airport

Kobe Airport

Chubu Centrair International Airport

Possible locations for floating airports in New Orleans.

Section Drawing of floating airport terminal. Foundation is below terminal with subway train stopping at elevator for passengers arrivals and departures.

COASTAL BARRIERS

Watergates

Coastal Barriers have used as defence in the threat of flooding and on occasion of a tidal wave or tsunami. Additional programs such as roadways,sustainable energy or additional programs can be added.

Stormbarriers placed at estuaries in The City of New Orleans

Watergates section drawing

THAMES BARRIERThe Thames River Barrier has a“barrel” like system that rotates to an open or closedsystem. The bottom is dredged out in order for the gate to close. The barrier is usuallyclosed 5 to 6 times each year. Flooding is a concern to London from offshore storms and torrential rain storms.

Piston (not shown, under metal hood) drives rocker arm which rotates barrier.

Barrier (shaded)

River bottom

Rocker arm

Water level

Barrier Section