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Commercial use of sediments from SW Pass?

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rivermouth1

Is this an appropriate location for an artificial barrier island to expand the economy and protect NOLA?

Editor’s note: On November 23 the state released a strongly-worded letter to Gary Locke, Secretary of the US Department of Commerce, requesting that Locke intercede to force the US Army Corps of Engineers (corps) to recreate some of Louisiana’s sunken landscape with the huge volume of sediments dredged each year from SW Pass in the lower Mississippi River.

The policy of the corps has always been to discard (waste) most of these sediments, which has fomented a long drawn out struggle between the state and the corps. A guest post by a coastal legal authority on the legal implications of the outcome of this struggle is under preparation. While awaiting what I’m certain will be an important contribution, growing disbelief that we continue to squander the sediments from SW Pass justifies the following thoughts on technical and policy considerations.

Background

Southwest Pass is the sole deep draft channel connecting the world’s largest port complex* between Baton Rouge and New Orleans with international commerce via the Gulf of Mexico. Approximately 60 From 5-20 million cubic yards of sediments (twelve 1 to 4 Superdome equivalents or SDEs) are dredged every year from SW Pass, about 100 miles downriver from New Orleans, to maintain a 45′ deep channel across the bar.

12 superdomes

From one to four Superdome Equivalents (SDEs) the volume of sediment dredged from SW Pass each year, most discarded

Maintaining the channel through SW Pass is the single largest (and most expensive) dredging project in North America, which is why the New Orleans District has the largest budget of all American corps districts. Under current corps policy, most of the channel dredging, which takes place 24/7/365, involves the use of both hopper dredges and so-called dustpan dredges that discard this valuable sediment back into the flowing river as a “waste.”

These critical sediments eventually wind up falling off of the continental shelf to be lost forever. The alternative, placing sediments from SW Pass beneficially in areas adjacent to the river upstream from Head of Passes, would greatly increase the direct cost, which is why the corps has resisted changing their policy.

The dirty little secret that has always been swept under the rug (using dust pan dredges) is that the cumulative cost of wasting this essential land-building resource is certain to be orders of magnitude higher than placing the spoil where it’s needed. It is patently irrational for the state to seek $100 + billion to save the Louisiana coast when the physical resource needed for that purpose is being sacrificed on the alter of navigation.

The Dredge Hurley keeps the Mississippi River free and clear for commercial trade barges daily. This is the Dustpan Head of the Dredge itself - the part that collects sediment from the River's bottom. © Marissa Watson / NGT&F  Read more: http://channel.nationalgeographic.com/series/worlds-toughest-fixes/3567/Photos#tab-Photos/0#ixzz0YJDhRgSB

The Dredge Hurley keeps the Mississippi River free and clear for commercial trade barges daily. This is the Dustpan Head of the Dredge itself - the part that collects sediment from the River's bottom. © Marissa Watson / NGT&F

Fantasy Island

On January 31, 2009 LaCoastPost published a story about a pet idea of State Senator A.G. Crowe from Slidell that has been called Fantasy Island. The concept would be to create an artificial barrier island in the southernmost part of the Mississippi River Delta between SW Pass and South Pass, using the “waste” sediments dredged from SW Pass.

The created island would house a commercial port facility to transship cargo on and off mega ships too large (deep draft) to navigate the channel upstream to the Port of New Orleans. The transshipping concept at the river mouth is not new.

A consortium of business interests was formed some years ago to obtain funding to build a state-of-the-art facility in lower Plaquemines Parish near Venice. This project, called by several names including Starpoint, Milennium Port or Superport, would use monster cranes to efficiently transfer containerized cargo between mega container ships and traditional barges.

On November 3 Jen DeGregorio posted a story on NOLA.com on Sen. Crowe’s concept, which appears to be independent of and in competition with the Plaquemines Parish project. Although her story included a quote from Garret Graves, chair of the Coastal Protection and Restoration Authority (CPRA), navigation projects and the commercial uses of the lower river are rarely discussed at CPRA meetings. In other words navigation and economic development still appear to be considered separately from coastal protection and restoration by the Jindal administration.

This irrational situation must change if the paradigm under which the river has been managed is ever to be fixed.

As far as I know, there has been no public discussion of the potential connection between Senator Crowe’s island and the state demand for the corps to stop wasting the sediment dredged from SW Pass. I question whether creating an artificial island at the river mouth for commercial purposes would qualify as a beneficial use for the channel mud.

My sense is that the region between SW and South Passes of the Mississippi River delta is an exremely poor place on which to create an artificial island, especially for commercial purposes that involved permanent residents.

caption

Appropriate place for an artificial island (perhaps a Fleur de lis instead of a palm tree design)?

This area not only subsides more rapidly than any other part of the coast, it would become the prime target for hurricane force and it is just north of a zone that was described in a technical paper by Hooper and Suhayda (2006) as historically subject to sea floor slumping.

On November 27 I stumbled on this post on the economic failure of Fantasy Island in Dubai. At least in terms of public relations, this situation doesn’t bode well for the potential economic viability of Louisiana’s Fantasy Island.

Len Bahr (len.bahr@gmail.com)

*Based on tonnage.

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  2. Anonymous says:

    Len,

    No worries.

    These types of numbers get thrown around in so many differrent forms and forums, it becomes difficult to keep them straight.

    Plus I have a bad habit of breaking out the red pen and marking up mistakes…..

    Keep up the good work.

  3. Stupidity does not stop at the Corp.
    This our fed in action (INACTION) IN St Tammany Parish..
    From the Parish Presidents new letter…..
    At this time, the federal government has allocated over $14 Billion in hurricane protection for the south shore. That same federal government has spent $0 for hurricane protection on the north shore

    http://www.stpgov.org/leadership_president_learn_more.php

  4. Len,

    you may want to check some of your numbers (or provide your references for them). The average cy dredged from SWP per anum is more like 15-20 million. Also, hopper dredges are used to maintain deep draft channel in SWP, dustpan dredges are used to maintain the deep draft crossings between BR and NO, as well as the shallow draft channel above BR.

    • Thank you for spotting my mistake (I think the 60 million cu yd figure came from a Times-Picayune editorial). It seemed high to me too but I didn’t take the time to check it. My bad.

      The following quote from a communication from the governor’s office of coastal activities is in line with your figure:

      Dredging of the Southwest Pass area to maintain proper channel depths for navigation and commerce involves the removal of 5 million to 20 million cubic yards of sediment each year. While the state of Louisiana strongly supports the maintaining of shipping channels, it has asked that beneficial use of the dredged material also be made a key component of the management of the river.

  5. Charlir Viosca says:

    I hate the Corps of Engineers. When they get an idea they persue it like Hitler and there is no reasoning with them.
    I like it when they catch hell and would do anything possible to see them disbanded. I klnow that will not happen but someday they it ma come to pass.

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