Homeland Security Watch

News and analysis of critical issues in homeland security

May 12, 2011

The mighty Mississippi tamed?

Filed under: Preparedness and Response,Strategy — by Philip J. Palin on May 12, 2011

Tuesday’s flood crest at Memphis exceeded the 1927 high-water mark and fell just short of the all-time 1937  record.  Yet as headlined by the Associated Press: Despite flooding, Memphis remains open for business.

In the eight decades since passage of the Flood Control Act of 1928 the Mississippi has become less a river and much more an engineered system of maintained channels, levees, and floodways.   In 1927 there were at least a thousand deaths and flooding left more than 600,000 homeless. This week  the threat was largely contained (broadly understood, see below).

The engineered system worked largely as planned. Many aspects of planning and implementation are undeniably impressive.   I am especially impressed that  floodways and the Bonnet Carre Spillway were built into the original and subsequent legislation and appropriations. Moreover water flow easements and other legal requirements for the floodways have been sufficiently maintained to survive a Supreme Court challenge.

The seldom-used floodways and spillway are a great example of trans-generational resilient design. Resilience is an outcome of anticipating turbulence by broadening and deepening the basin in which turbulence can occur while the system maintains its essential character. The US Army Corps of Engineers estimated that opening the Bird’s Point Floodway in Southeast Missouri may have redirected as much as 550,000 cubic feet per second of water volume. (Read more about the floodways at the USACE Mississippi River and Tributaries Project website.)

A couple of cautionary notes:  The typical flow rate for the Mississippi is about 450,000 cubic feet per second.  This week at Memphis the river was running about 1.4 million cfs.  In 1927 the flow rate reached 2,345,000 cfs.   How would the levees at Memphis have dealt with an extra million cubic feet per second? When the flood peaks next week at Vicksburg it may over top some levees by up to 12 inches.  In non-protected or low-priority areas along the river and in the delta the high water will consume everything in its path.  This is part of the system’s design.

The US Army Corps of Engineers organizes its design, development, and management around a “hypo-flood” that anticipates 2,710,000 cfs at the confluence of the Mississippi and Yazoo Rivers near Vicksburg.   Fortunately, the mid-South precipitation forecast is mostly scant until the middle of next week.  The upper Mississippi is past its surge. This suggests continuity of the current system.

Many engineered systems (and ecological systems) are characterized by a certain precariousness.   The system is adaptive and resilient until — suddenly — it is not.   When the adaptive capacity of a system is exceeded, a cascade of failures can result in catastrophic collapse.  Tuesday in Memphis we stayed on this side of that terrible threshold.  Barring some surprise (this would be a bad moment for the New Madrid fault to rock-and-roll) the lower Mississippi “system” should continue on its present edge for the next week and more.

We pay a price — and not just financial — for engineering the Mississippi.  There are several negative, often unintentional consequences worth our attention (in another blog).  But at Cairo and Memphis the system performed as planned.

Fundamental to our comparative success this Spring has been an acceptance of our limitations.  The floodways reflect prudent preparedness for the extraordinary, the infrequent, and the potentially catastrophic.  How might we systematically apply this principle to policy, strategy, planning, and management for other areas of homeland security?

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6 Comments »

Comment by John Comiskey

May 12, 2011 @ 6:22 am

Briefly and in broad terms, homeland security strategists, planners, and managers offer Mississippi-river-mitigation for homeland security.

Some of it is lost in [pork barrel] politics and parochialism. The Mississippi flood-mitigation system is instructive as are most counterfactual and especially catastrophic counterfactual prevention and mitigation initiatives in that the need for the system was and is self-evident. Stakeholder participation is an imperative.

I am curious as to those non-protected and low priority areas and not in the pejorative. Why are they non-protected/low-priority? When was this decision made and how are the non-protected/low priority areas reconciled? Nudges? Insurance? Subsidiaries? To be clear; there may be good/great reasons to prioritize. Moreover, IMHO it is in identifying the non-protected-low-priority stakeholders and bringing them to the table that homeland security initiatives might paradigm.

QHSR 2010 identified HLS as “ultimately” being about National Security. UBL’s demise may advance the all-hazards approach to HLS and maybe a folding of HLS into National Security and particularly to include educational, economic, and climate security.

Comment by William R. Cumming

May 12, 2011 @ 7:31 am

Well an interesting post by Phil! Too soon to tell would be my call as to whether the “system” worked! Why? Most of the river south of Cairo Illinois was leveeed post the 1927 flood described by John Barry in his Rising Tide. Of course it had nothing to do with tide.
The problem is this system is aging in many places and the fact that it was largely built with WPA workers and dollars means it could not be built today or perhaps even repaired. It may not be my life time but the River will ultimately win. Morganza spillway I thought was already partially open and the Old River Control Structure is another point of stress to watch.

The NOLA some of this system designed to protect will eventually be lost to one of its five major flood challenges. That is in fact now why NOLA is no longer ranked 38 in population by the 2010 census and in fact never was dominant in the financial sector like it was pre-1927. NOLA is a city largely preserved by mythology not reality.

And Memphis is a huge city but still will have significant flooding for the rest of the month. Now on to Vicksburg and Natchez?

Comment by Philip J. Palin

May 12, 2011 @ 8:31 am

Bill, I very much share your concern regarding long-term maintenance. Related is the increased risk being attracted by the risk-management system itself. But I spend so much time questioning the value of command-and-control(Newtonian) approaches I feel ethically compelled to notice when an engineered system engaged a staggering threat and did its job as designed. Whatever happens next, at Cairo and Memphis the system worked.

John, you raise some important questions, worth more time than I have right now. But there is a piece in this morning’s Washington Post that begins to address your questions. Please see: A Choice Between Two Floods.

Comment by William R. Cumming

May 12, 2011 @ 7:50 pm

Saturday AM decision will be made to open Morganza Spillway.

Comment by William R. Cumming

May 13, 2011 @ 11:31 pm

Apparently decision made to open the Morganza Spillway over next several days. USACOE has released maps showing expected innundation of lands. WOW! First opening since 1953?

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