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Mitigating for MRGO with the Inner Harbor Navigation Canal


Images at two scales from Google Earth

Figure 1a (top) and Figure 1b (bottom) Images at two scales from Google Earth

by Len Bahr, PhD*Len2.21.10

After years of brainstorming about effective ways to reconnect the Mississippi River to its dying delta I rarely hear truly novel ideas. Navigation and environmental stakeholders traditionally find themselves at loggerheads, so it is even rarer to hear an idea that could serve both important navigation and coastal restoration goals.

Last week a colleague and expert on hydraulic engineering whispered just such an idea into my ear. This person eschews politics and wishes to remain anonymous, but I am happy to endorse what I believe is a truly important and deceptively simple concept.

The idea is to turn an expensive, plain vanilla, single purpose navigation project in the Pontchartrain Basin into a dual-purpose project to help mitigate the enormous environmental destruction caused by the Mississippi River Gulf Outlet (MRGO).

IHNC Lock replacement

Navigation interests have long lobbied for authorizing and now completing a $1.3 billion replacement lock for the Inner Harbor Navigation Canal (IHNC) structure in eastern Orleans Parish, where it connects the Gulf Intracoastal Waterway (GIWW) to the river (Fig. 1a). The existing lock, built in 1921, is too narrow and shallow to accommodate new generation barges in the GIWW between the State of Mississippi and the Mississippi River (Fig. 2).

Inner Harbor Navigation Canal Lock Replacement Project (graphic from the USACE)

Figure 2. Inner Harbor Navigation Canal Lock Replacement Project, which could double as a major conduit for river water. Ggraphic from the USACE)

This IHNC lock replacement project has been cussed and discussed for years. It has strong political support from the Port of New Orleans and from Senator Mary Landrieu, especially since the Mississippi River Gulf Outlet (MRGO) was closed to shipping in 2009. I have little doubt that New Orleans’ Mayor-elect Mitch Landrieu is also a strong supporter of the project. For example, Port of New Orleans’ CEO Gary LaGrange is on the economic development council appointed by the soon-to-be Hizzoner.

On the other hand, the IHNC lock project has had virtually no support from the environmental community and it has been locally opposed in the Holy Cross neighborhood. Environmental attitudes about the IHNC could change dramatically, however, were the project to morph into a critical river water conduit to protect NOLA.

The project was authorized under the Water Resources Development Acts (WRDA) of 1986 and 1996. Limited funds have been appropriated for site preparation and pre-construction has been underway since 2003. Recently, however, the project has stalled over concerns about the adequacy of its environmental impact assessment.

The latest roadblock involves stripping IHNC project funding from the 2011 Corps budget. This decision implies little interest in or support for the lock replacement by the Obama administration. Our two senators have been attempting to restore the construction funds in the corps budget, with a limited chance of success.

Proposal: use the IHNC project to mitigate MRGO

After winning the long struggle to close MRGO, the challenge for coastal restoration throughout the Pontchartrain Basin has shifted to stopping the bleeding from MRGO and mitigating at least some of the extensive damage created by that ill-conceived canal. Virtually all experts agree that achieving this goal depends fundamentally on conveying a significant volume of river water and sediments to the central part of the basin, including the Biloxi Marshes in eastern St. Bernard Parish.

So far, the primary means discussed for this purpose is a conveyance canal that would be dredged from the river at Violet to the upper end of the MRGO that would convey roughly 7,000 cubic feet per second (cfs) of river water. This proposed diversion project is on the relatively modest scale of the Caernarvon project that was completed in 1990. It would be locally beneficial but could not handle a volume sufficient to have regional impacts on the Biloxi Marsh target area (Fig. 1b).

In general, the further upriver a diversion project is located within the delta the more effectively it can disperse water and sediment to dying wetlands. The IHNC structure is about seven miles upriver from Violet and, with expanded channel dimensions of 110′ width x 36′ depth, it could convey river water at a flow rate sufficient to significantly impact the target zone. The hydraulics expert who suggested this concept assured me that a relatively high (but unspecified) volume flow would not compromise the operation of the lock for barge transit.

No site for river water conveyance has been identified on the NOLA East Bank equivalent to the IHNC location, except for the Bonnet Carre’ floodway. The latter site, which discharges nutrient rich river water into the west end of Lake Pontchartrain, is forty miles west of the Biloxi Marsh target zone and has a very checkered history with the environmental community.

Expanding the scope of the IHNC project to include discharging a large volume of river water eastward along the GIWW would play a key role in preserving the Biloxi marshes to the east. Wetlands to the south will likewise depend on the proposed Myrtle Grove diversion project and its east bank counterpart, roughly 30 miles downstream from the IHNC project.

What’s wrong with the IHNC diversion concept?

The primary problem with the concept of adding a restoration function to the authorized IHNC project is bureaucracy. Proposing a significant design change could jeopardize the official WRDA authorization after many years of negotiation.

This concern is obviously warranted but it reflects a mind set from the pre-Katrina, pre-Superbowl, pre-Mayor’s election era. We’re now in a race against time, which demands new thinking.

IHNC replacement as a guinea pig for streamlining WRDA

Louisiana officials have long complained about bureaucracy within the Corps of Engineers and called for short-circuiting or bypassing the WRDA process, which typically requires forty years between project authorization and construction. The proposed modification of the IHNC project could serve as an ideal test case for challenging the status quo.

Streamlining the corps will be more than a cosmetic exercise

Streamlining the corps will be more than a cosmetic exercise

Winning this break with tradition would require a full court press, using all the political tools at our disposal. We should recruit former Senator John Breaux and his lobbying partner Trent Lott,** former Congressman and lobbyist Billy Tauzin and, of course, Mitch Landrieu. The current hiatus in IHNC project construction provides a perfect opportunity to mount a multi-pronged campaign to convert a classic public works project that reeks of pork into a centerpiece restoration project for the entire Pontchartrain Basin.

The three national environmental groups that have adopted Louisiana’s coastal effort*** would presumably endorse this campaign to turn the IHNC lemon into lemonade. These NGOs could effectively seek support in this mission from the new White House Interagency Ocean Policy Task Force.

The challenge would be to convince the Obama administration and congress to seek emergency authorization for an expedited engineering/design effort to convert the original IHNC replacement project into a high profile dual-purpose project. This keystone project would complement and rival in importance the $1.3 billion IHNC Lake Borgne surge barrier that is currently under construction.

The replaced lock structure should be designed to pass the maximum flow**** into the GIWW during high river stages that would not hamper navigation. Design modifications to effect this function should not be particularly complicated or expensive. As lagniappe, this change would dramatically expand the environmental benefits of the project, far exceeding its environmental costs.

*Founding editor (

**Former Mississippi Senator Lott has long used his considerable political clout to pressure Louisiana to divert Mississippi River river water toward his home state. He could have a huge influence on congress to authorize an expanded IHNC project.

***Environmental Defense Fund; National Wildlife Federation and the National Audubon Society.

****I originally suggested the very ambitious flow rate of 50K cfs but my hydraulics advisor suggested a non-specific but more modest target.

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  1. You put your mates information for shipping address.

  2. chris lerouge says:

    Good God, i’ve been saying this for yearsss! People look at me like im nuts. THey should put a lock at the Highrise and then let the st.claude locks open up full blast down the ICWW and then MRGO! talk about build up of sediment? Of course the CORPS and their infinite lack of wisdom built this huge ass wall across mrgo. FOR CHRIST Sake ROME IS BURNING! it doesnt take a rocket scientists to figure this out, just someone with enough testicles to let the river go at EMpire, violet, carnavon, Niomi (that’s just above the BP plant in jesuit bend), and at St. Claude street. To hell with the oyster fishermen!

  3. Kelly Haggar says:

    Echo from last month; Kelly Haggar on 2010-02-23 at 15:32:21.

    “Slides for the Violet Diversion program last night are at:

    The existing canal shown with red arrows at Violet was one of the 3 rejected options. The Arcadis studied plan selected by the Corps goes through the Meraux dot on Len’s map. It’s the last developable tract of any size in the whole parish. Post-Katrina Kathy spent Jan-Mar 06 as part of FEMA’s ESF-14 task in St .Bernard working on their recovery plan. Every state and national team (paid and volunteer) which came down to look at the Da Parish wanted to put their project in that cattle pasture. Now the Corps wants to run a diversion through it.

    Yeah, there’s some local opposition . . . .

  4. Its nice to see some creative thinking on IHNC. I’ve always thought that this project would be well served by a dialogue that goes beyond “yes or no/stop or go” approach. I think the Port has a legitimate concern with the age and functionality of the lock, as well as its dimensions. One problem that Len does not address here is that the current design of the lock isn’t geared toward the size of the “new generation” barges he is referencing. It’s dimensions are intended to accommodate moderately-sized ocean-going container traffic. Its a relic of when the port was attempting to develop a container handling facility on the GIWW. That plan has been abandoned for years, and the Port of NOLA has admitted in the past that we need to “forget about” container handling sites on the IHNC entirely. That’s what Napoleon Ave. is for. So instead of building a small lock designed for barges that can operate rapidly to handle upticks in traffic, we’re getting another behemoth of a lock that will lead to 300,000 cubic yards of sediment being dumped on the north bank of Bayou Bienvenue. These sediments have been found to be “acutely toxic to benthic animals” – that’s the Corps’s own EIS talking right there. While the dredged sediments from the river certainly deserve some “beneficial use,” I’m not sure that the IHNC sediments have any beneficial use beyond their current semi-sequestered state. Also – I would imagine that having the lock double as a sediment diversion would cause all kinds of dredging issues in the IHNC/GIWW, not exactly something that the Corps is going to be too keen on considering that the MRGO court decision zeroed on their poor maintenance of the MRGO. I’m no engineer, but I would assume that this would require a bottom-up redesign of the entire project. As of today, the Corps has redesigned this project for at least FIVE different sites, and has redesigned the functionality and construction method at least a dozen times. So Len is correct that convincing the Corps to undertake this would require a “full court press” – they would need to see support from all quarters, HCNA and its allies, the Port, etc, to undertake something like this. We all know that getting the restoration arm of the Corps to collaborate with the development arm is nearly impossible – and the MRGO restoration team wants nothing to do with the lock replacement project, I can tell you that for sure. The lock was authorized in the same bill as the MRGO. Too close to home for them I think. We need to move beyond the binary nature of our discussion of this project and put some ideas out there that can garner support from a variety of actors. Well done.

  5. Great idea and post!
    But you should take a look at the BreauxLott client list:
    and tell me most of those people don’t understand the economics of Shipping over Water as opposed to Land.
    Tauzin is loose now from Ho’Doggin for Pharma, but really, come on who’s got that kind of grease?
    But this is one of the best Ideas I’ve seen in a while.
    Is it too simple to work?
    Remember, no Land no Property Rights.

  6. Don Boesch says:

    Born and raised just blocks from the IHNC Lock and having crawfished in the what-used-to-be swamp east of the canal in back of the Lower 9, I see this as an interesting proposal. However, an obvious question concerns the degree of sedimentation and channel shoaling that would result as the IHNC and GIWW widen.

  7. Ted Falgout says:

    I have been saying we should do this ever since the MRGO was marked for closure.
    I also agree that NOW is the time to marry navigation with Levee protection and Restoration.
    We should evaluate every lock we have south of NO to determine how much water we could allow through them on a regular basis.

  8. Jim Rives says:


    Your graphic fostered deep feelings of nostalgia in me. In 1980 I made a graphic with a yellow highlighter and a really big blue line map to illustrate water flows for a St. Bernard Parish presentation to Colonel Sands and some Port of New Orleans grandees on the subject of using the Inner Harbor Locks for freshwater introduction.

    Thus, I’m not sure how novel this idea is, but I think that it does have merit.

  9. HeidiHoe says:

    Who needs navigation when dug out canoes worked just fine in ages past????

  10. Your comment has merit. A diversion here could reduce the size of diversion structures elswhere in the Upper Pontchartrain Estuary.

  11. It seems to me that we can’t just say that flood protection and coastal restoration are linked, and leave it at that. Navigational is the third sphere of sustaining Louisiana’s coast, and when talking about flood protection & coastal restoration, we can’t ignore navigation. While I can’t comment on the specifics, I like this proposal in general because it involves all three. And, since navigation generates revenue, it would seem to increase the likelihood that this coastal restoration and flood protection protection project will get funded.

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