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Don’t sneeze at Atchafalaya policy changes! Part one: adjusting the coastal faucet


Editor’s note: This is the first of a two-part series discussing far reaching modifications in management policy re the Atchafalaya River, changes that will affect all of south Louisiana. These shifts include considering: (1) altering the historic flow ratio between the Atchafalaya and lower Mississippi Rivers; and (2) expanding the Louisiana coastal area to include the Atchafalaya basin.



The July 5th Advocate carried a lead story by Richard Burgess on the fact that the US Army Corps of Engineers (corps) is at long last considering changing its rigid decades-old policy of maintaining a constant 70/30 split of the lower Mississippi River flow, with 70% always heading toward New Orleans and 30% of the combined Red and Mississppi flow toward Morgan City.

This marks a real paradigm shift that’s not to be sneezed at! It’s an all too rare occasion to celebrate and commend the corps. Read on.

Varying views of the Atchafalaya

One of the most prominently mispronounced names in Louisiana is “Atchafalaya,” phonetically adapted from a Choctaw name meaning “long river.” This name is ironic for a short river with a huge flow capacity. At only 135 miles in length and a potential flow volume of ~1 million cubic feet per second (cfs) the Atchafalaya has by far the highest flow/length ratio on the continent!

No matter how it’s pronounced, Atchafalaya conjures up widely disparate pictures in the minds of those familiar with the name:

Truckers driving I-10 between Los Angeles and  Jacksonville cross the Atchafalaya Basin on a 19 mile causeway, where speeding tickets are generously awarded. I’m sure that this stretch has generated colorful nicknames.

Louisianians appreciate the Atchafalaya as the source of most of the wild crawfish consumed locally each year. The watermen and women who supply this demand appreciate the Atchafalaya as a significant source of their annual income.

Nature lovers, including poets,* fishermen, hunters, kayakers, birders and ecologists think of the Atchafalaya as the largest and most bountiful freshwater swamp ecosystem in North America. Wildlife photographers including the well-known CC Lockwood happily provide books of Atchafalaya Basin photographs for coffee tables constructed of polished slabs of ancient bald cypress lumber.

Long before oil and gas resources distracted basin landowners from their economic interest in surface issues, families and corporations benefitted royally from Atchafalaya bald cypress lumber. Sadly, most of the 1,000+ year old trees that provided this beautiful red, rot resistant lumber were logged out by 1920 – many for railroad ties.

The corps views the Atchafalya Basin primarily as a hydraulic conduit or floodway, the principal relief valve for the maximum flow volume likely to be experienced in the lower Mississippi River system within five hundred years. The corps-speak term for this “hypothetical” future event is Project Flood. Because of its status as a national floodway,** the corps has ultimate authority over the Atchafalaya.

I think of the Atchafalaya as the most promising source of river water available to sustain south Louisiana.

The “Simmesport spout”

Atchafalaya basin shown in green. Simmesport is located at the "LA" on this map.

Atchafalaya basin shown in green. Simmesport is located at the "LA" on this map.

Simmesport Louisiana is a small town at the very center of Louisiana, strategically located just south of the end of the Red River (the southernmost Mississippi tributary) and the beginning of the Atchafalaya River (the northernmost Mississippi distributary). Simmesport also lies a mere eight miles west of the Mississippi mainstem.

Wikipedia includes a description of Simmesport the birthplace of Norma McCorvey, a.k.a, “Jane Roe,” the plaintiff in Roe v. Wade. I find it curious that the information listed for this otherwise unremarkable small town doesn’t mention its unique location at the nationally-significant nexus of these river tributary and distributary systems.

This strategic location represents the tip of the spout of the vast watershed “funnel” that collects water from 41% of the lower 48 states and a small part of Canada. All the precipitation collected by this funnel that hasn’t evaporated by the time it reaches Simmesport must pass through this spout.

It’s difficult to appreciate how much power this flowing water represents, especially during spring when total combined flows of the Red and Mississippi average about 1.3 million cfs. For comparison, imagine 130 Potomac Rivers flowing past Washington DC!***

The Old River Control Structure – the world’s largest faucet

When Mother Nature was still in control the Simmesport spout resembled the nozzle on a watering can, sprinkling water throughout the delta via multiple distributaries. Mother nature has been displaced (temporarily, I’m sure) as the river manager. This occurred after the largest historic flood of the river system in 1927 prompted the US Congress to order the corps to build the $11 billion flood control/navigation initiative known as the Mississippi River and Tributaries Project (MR&T).

The MR&T project eliminated the watering can distributary system by constraining all river water to two leveed and channelized waterways unable to sustain the delta. Equally damaging was the decision to maintain an unchanging flow ratio between these two waterways, presumably to preclude political disagreement and controversy.

Faucet systems are used to adjust and optimize the volume from two supply pipes coming into a basin. That’s why it’s strange that the corps, arguably the world’s largest plumbing company, installed the world’s biggest faucet in the 1960’s and upgraded it in the 1970’s, only to post a “do not adjust” sign on the device.

Despite entreaties by many Louisianians, including former Gov. Mike Foster, the corps has steadfastly refused to consider significant adjustment to the traditional flow ratio between the Atchafalaya and Mississippi channels. This ratio has no technical significance whatsoever. It’s just a round number based on data from the 1950’s, long before Louisiana’s coastal crisis had been widely recognized.


Left spigot: Atchafalaya, right spigot: lower Mississippi

Now, for whatever reason, the corps’ opposition to consider adjusting the flows between the two spigots so as to better sustain the coast appears to be softening. I happily raise a glass of wine in toast and say, “Better late than never.”

The most concise and understandable description of the Atchafalaya River system of which I am a aware was a product of the Loyola University Center for Environmental Communication (LUCEC). I assume that the piece was written by director Bob Thomas and I strongly recommend reading it for a description of the history and design of the ORCS “faucet.”

Part two coming soon…

Len Bahr

*For example, Henry Wadsworth Longfellow: “Evangeline.”

**The corps also manages the Atchafalaya for navigation, but although long involved in regulatory (wetland permitting) issues such as oil and gas pipeline and logging permits within the basin, the corps has never viewed the Atchafalaya as a fundamental part of the coastal ecosystem.

***A token portion of this power has been tapped since 1990, when the Sidney A. Murray Hydroelectric Plant (the only plant of its type on the entire Mississippi River system) was installed between the Mississippi and Atchafalaya rivers to take advantage of the small difference in head between the two rivers.

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  2. Len Bahr says:

    Your statement is correct about congressional establishment of the 30:70% split (which goes back to the fifties). My sense is that congress set this ratio on the advice of the corps, however, and I think congress would approve changing the ratio if approached with supportive science. I think the corps has assumed that this woud entail a political hassle so they've avoided the issue. The corps should focus on providing technical advice, not prejudging what the politics will support.

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  4. Len Bahr says:

    An additional thought. For years agency and engineering groups have explored three separate concepts: (1) increasing Atchafalaya flows into the Terrebonne marshes; (2) an artificial conveyance channel into the Terrebonne and Barataria basins (3rd delta concept of Woody Gagliano); and (3) releasing huge volumes of water into the Barataria and Pontchartrain basins above Head of Passes (so-called hang-a-left, or delta management project). Each concept is affected by and absolutely constrained by the other two and by the flow ratio at the Old River Control Structure but each concept has been discussed in a vacuum. Go figure.

    • Will Courtney says:

      Len,wasn't the flow ratio set by congress? I forget what Latitude line is used but I understood that at (whatever latitude) the combined flow from both the Red and the Atchafalaya could not exceed 30%of the combined flow of all three rivers and that there is a 5% allowable adjustment that can be made by the Corps. Is this correct?


  1. The Ratio of the Atchafalaya to the Mississippi « Quinta Scott’s Weblog - [...] for Atchafalaya water and sediment for rebuilding wetlands in the Terrebonne Basin. Len Bahr at lacoastpost explains the role…

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