Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?

CONS
• Very expensive
• Not cost effective

Since the wall is above the force couple, the taller the wall becomes the longer the lever surge forces have to apply pressure to. In order to resist overturning the base must be extremely heavy (4′ to 5′ thick) and H-piles must be extremely deep. In many cases they are driven to a depth of 120′. Because they are driven in at an angle they must be considerably longer than 120′ to reach that depth

The Army Corp of Engineers estimated cost is $14,000 to $19,000 per linear foot. That comes to $75 million to $100 million per mile.

There are hundreds of miles of levees that cannot be built because short tracks of t-wall levees have sucked up all of the funding.

I-walls do not work because they rely on the passive pressure of the soil, which is the horizontal pressure of the soil. The passive pressure of the soft soils in the New Orleans area is not very strong.

The force of the storm surge is exerted on the top of the wall and the bottom is not supported by the soft soils.

In addition,  the height to which an I-wall can be built is limited,  and over topping scours out the soil supporting the backside

Seepage is also a major problem.

Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur?

If a clay levee is properly built tall enough, wide enough, and given enough time to compact, there likely won’t be a failure. However, The cost of properly building clay levees tall enough and wide enough is ENORMOUS due to the shear size of the structure. Earth levees that are expected to withstand powerful tidal surge must be very wide. In many cases a levee with an elevation in excess of 20 feet must be 500ft-750ft wide. The levee itself might only be 120ft-150ft wide, however, expansive rinforcing berms (150ft-250ft) must be put on both sides of the levee. This helps to keep it stable and prevent global failure. All of this extra clay and the expropriation of property is expensive.

Sam Z. Scandaliato, P.E.
S.Z.S. Consultants, Inc.
616 Baronne Street, Ste. 302
New Orleans, LA 70113
Phone: (504) 561-5724
Fax: (504) 561-5726                                                                                                   

Email: samzscan@bellsouth.net

CLAY LEVEES

Estimated at $4,000 to $8,000 per linear foot, without the cost of buying land owners property to build them wide enough.

When proposing that hundreds of miles of clay levees be built to protect South Louisiana the same questions are repeatedly given.

• Have we located enough clay to build these levees?
• How much will all that clay cost?
• Where will it come from?
• If we use the best land for borrow, what are we protecting?
• They say to go higher they will have to go wider. Will they have to take my land?
• How long will they take to build?
• What is the impact on the environment and infrastructure?
• How do you control compaction of the clay used for the levees?
• How do you account for massive underground subsidence due to the weight of the levees?

THE TRUE COST OF CLAY IS HOW MUCH?

Because of the vast need for clay and the shortage of it, the price seems to have escalated. The cost of the clay, ultimately, could be unknown. Buying it, digging it and moving it is only part of the cost.

It has been said that the best land to build on or farm is the same land that is being proposed for borrow. It is the marginal land that is unsuitable for farming, industry, or clay for levees. This is a problem because know one wants to have thousands of acres of holes in the ground where good land used to be. Once these pits are opened the land becomes forever useless to agriculture, industry, or expansion of the population. The clay is moved and put in place for near $35 per cubic yard, and that is the last time that land will benefit the the economy or the people in any meaningful way.

• No more cattle.
• No more sugarcane
• No subdivisions
• No warehouses to support industry
• … EVER!

YOU’RE TAKING MY LAND?

In addition to finding enough clay, earth levees that are expected to withstand powerful tidal surge must be very wide. In many cases a levee with an elevation in excess of 20 feet must be 500ft-750ft wide. This means enough land must be taken(with compensation) from the land owner to facilitate the width of the structure. This adds to the cost of the levee significantly. However it should be noted that in many cases this is not factored into the construction cost. The land must be purchased by the local government, and then right of way is given.

T-WALLS

There are no peripheral cost of T-Walls. The construction costS are enough.

Estimated at $14,000 to $19,000 per linear foot

($75 million to $100 million per mile)–The New Orleans District alone has 330 miles of levee. Will there ever be enough funding for the whole State to have this? Not likely.

DOUBLE WALL IMPACT PROTECTION LEVEE

• It does not have the peripheral cost that a clay levee has–fits in existing rights of way.
• It uses no clay–Sand is readily available and cheap.
• It can be constructed quickly–It does not need months or years to settle.

The Double Wall design offers surge protection similar to that of a T-Wall design, with a construction cost similar to that of an earth levee.

Estimated at $5,000 to $6,000 per linear foot

Advantages:

• Fast, simple installation
• Low maintenance
• Can be built in the existing rights-of-way
• No expropriation of private property required
• No seepage problems
• Saves taxpayer dollars
• Uses the existing soil conditions to maximize protection
• Protects against surge up to a Category 5 hurricane.
• Does not rely on mechanical pumps
• No special soils (clays) that are required for earthern levees
• Eliminates the need for huge clay pits that would cause severe area subsidence
• Higher, stronger, and less expensive than T-Wall levees
• No grass to grow and maintain
• Optional protective zinc coating on exposed steel eliminates any future maintenance.