shrug-l: And You Think We Have Flooding Problems In Florida

C. Henry Depew sisu26 at
Fri May 13 17:59:23 EDT 2011

     I read about this spill way and the 
potential problems if it failed many years 
ago.  It seems that the projected problem may come to pass after all.


>The Morganza Spillway flood control structure in 
>Pointe Coupee Parish could open as early as 
>Saturday but it could be delayed until Tuesday, 
>May 17, depending on conditions, the Mississippi 
>River Commission president said Monday. “If we 
>operate Morganza, there won’t be overtopping. If 
>we don’t operate Morganza 
 about three miles 
>south of Baton Rouge, we will have significant 
>overtopping there. LSU and a couple of other 
>significant infrastructure would be inundated,” 
>said U.S. Army Maj. General Michael Walsh of the Army Corps of Engineers.[1]
>The Morganza Spillway was opened for the first 
>and only time in 1973 to relieve pressure from 
>the Old River Control Structure (ORCS). [2][3] 
>The spillway received minor scouring and slight 
>damage to the stilling basin. After the 1973 
>flood, the structure was restored to its 
>original condition. In 2008, a flood caused 
>portions of the levee at the spillway to 
>deteriorate and sent floodwaters into cropland 
>located within the floodway. [4] It is because 
>of this damage to the levées around the spillway 
>and the extent to which the structure itself was 
>undermined by just the '73 test that the 
>Morganza Spillway has never been opened since, 
>though it would have been useful during several 
>subsequent years to relieve pressure on the Old 
>River Control Structure. Studies by the Army 
>Corps of Engineers after the test determined 
>that once opened, it would likely never close 
>again, and could be ripped from its footings, 
>allowing the Mississippi River to jump its banks 
>and flow primarily through the Atchafalaya 
>Basin. While this would leave New Orleans, Baton 
>Rouge, and the Port of New Orleans practically 
>high and dry, the Atchafalaya Basin would become 
>the the main artery of the Mississippi River 
>below Morganza and several cities along the 
>bucolic Atchafalaya River would be flooded and a 
>new delta would begin forming immediately. The 
>failure of the Morganza structure would be 
>disastrous beyond imagination for the residents 
>of south Louisiana and international commerce.[5] [6]
>Read the following description of the scenario 
>surrounding the failure of the Old River Flood 
>Control Structure. This scenario would be 
>unimaginable and far worse than Katrina or 
>anything else we would ever experience. I would 
>be willing to guess there is no emergency plan 
>in place for this scenario. I hope like hell this never happens.
>One of the reasons that people suggested that 
>the Atchafalaya would eventually "capture" (that 
>is, the main flow of water through our state 
>would exit Morgan City instead of its present 
>location at the mouth of the Mississippi) is 
>that the distance is so much shorter and steeper 
>to the Gulf via the Atchafalaya than the meandering Mississippi:
>- Old River Control Structure to Gulf via Atchafalaya: 142 mi
>- Old River Control Structure to Gulf via Mississippi: 335 mi
>If the events of 1973, as described above, 
>happened, how would life on the lower 
>Mississippi and Louisiana coast change? The 
>following description of possible life after the 
>change is excerpted from Kazmann and Johnson (1980:10-16).
>In the aftermath of the huge floods that would 
>cause the main flow of the river to jump to the 
>Atchafalaya River, aside from the cost, anxiety, 
>tragedy, and aggravation of dealing with massive 
>amounts of water being in the wrong place, there 
>would be lingering issues that would change the 
>way of life on the lower Mississippi. Instead of 
>70% flow down the lower Mississippi and 30% flow 
>down the Atchafalaya, the percentages would 
>probably reverse. The Atchafalaya would be a 
>rushing, raging river, even during the fall for 
>a period of time until it scoured the channel 
>and filled in the lower reaches so that the flow 
>would diminish. Morgan City would have to be 
>relocated, as would other communities and many 
>businesses, possibly including the massive 
>infrastructure of the offshore oil and gas 
>industry. Fisheries would be altered measurably 
>all across the delta. Oyster reefs would be 
>immediately destroyed, and would take several 
>years to reestablish and become productive. It 
>would probably take two decades to adapt to the 
>new environment around present day Morgan City. 
>Additionally, pipelines, bridges, and the like 
>that cross the Atchafalaya would be destroyed or 
>rendered unsafe. The ruptured natural gas 
>pipelines would place stress on fuel supplies 
>for energy companies, but they would quickly 
>change to more costly fuel sources and have 
>little or no interruption of service. Imagine 
>the traffic jams when and if bridges on I-10, 
>U.S. 90, and U.S. 190 collapse (what about the 
>railroads)? All trans-state traffic would have 
>to be rerouted to I-20 via I-55 through Jackson, 
>Mississippi, adding up to 615 miles to the trip 
>(not to mention time delays from the traffic 
>jams). The protective levees of the Atchafalaya 
>Basin would have to be upgraded to handle the new pressure from spring flows.
>The lower Mississippi would still have a copious 
>amount of water, but it would be slack compared 
>to today. Shipping could continue to be an 
>important industry, but it would be interrupted 
>for a time. The slack water would allow (cause) 
>the thalweg to fill in and stop deep-draft 
>shipping. However, after intensive dredging 
>efforts it may be found that a 50 ft channel can 
>be easily maintained because of the tremendous 
>decrease in sediment. New Orleans, possibly 
>Baton Rouge, and all other cities and towns 
>along the lower Mississippi would no longer be 
>able to get their drinking water from the river. 
>It would become too salty, since the lower fresh 
>water flow would not offset the tidal movement 
>of the Gulf. Can you imagine the cost of piping 
>or trucking enough drinking (and flushing, etc.) 
>water from north of Lake Pontchartrain to supply 
>the needs of Greater New Orleans? Can you 
>imagine Greater New Orleans without water for 
>drinking and sanitation? Even when the water was 
>just barely increasing in salinity, there would 
>be severe damage to water heaters, fire 
>sprinklers, fire truck pumping systems, and 
>more. As mentioned above, the fisheries 
>(especially those associated with the fresh 
>water river) would suddenly change. And what 
>about the massive petrochemical industry 
>corridor? Aside from the impact on shipping, 
>which they could weather over time, industry 
>could no longer use fresh river water for 
>thermo-electric cooling. The saltier water would 
>corrode all the pipes and related 
>instrumentation. Of course, industry would 
>change to salt-tolerant materials, but that 
>would be costly and time consuming. Also, the 
>sugarcane industry would have problems without sufficient fresh water.
>All of this adjustment, and we have not delved 
>into the intensity of impact on people's lives 
>during the crisis and the adjustment period. All 
>normal routines would stop. Businesses would be 
>closed, as would schools, normal government, 
>etc., etc. Virtually the entire population would 
>spend months and months just coping - just 
>putting their and others' lives back together. 
>Imagine the emotional strain to the population - 
>people losing a lifetime of accomplishment. This 
>would be a tragedy of monumental proportions. It 
>would interrupt life much like World War II.
>One can also imagine the impact on the nation. 
>Massive use of Federal dollars to protect and 
>restore Louisiana's infrastructure. Loss of 
>natural gas (there would be brown-outs 
>throughout the eastern seaboard). Commerce would 
>be interrupted by restriction of travel and 
>Louisiana=s inability to focus on supplying 
>items traditionally demanded from her natural 
>resources by the nation. Prices of all Louisiana 
>products (from the natural resources [fisheries, 
>oil, gas] to industrial products [poly vinyl 
>chloride, polyethelene, etc.]) would soar. The 
>interruption of the pogie fisheries would be 
>very negative for such food industries as 
>chicken, catfish, and hogs. New Orleans is one 
>of the most important ports in the nation, and 
>it would suddenly cease to function; all 
>shipping and related industries on the 
>Mississippi River would stop. International 
>trade would be further imbalanced. The massive 
>fertilizer business would shut down and the agriculture industry would falter.
>And what about the economy of south Louisiana? 
>For a period of time, all the revenue would dry 
>up and tourism would collapse. Even Mardi Gras 
>would possibly come to a halt!!! Only the 
>mosquitoes would do well! And probably the cockroaches and Formosan termites.
>Long term, we would adapt. Once the drinking and 
>sanitation water issues were resolved, tourism 
>would return. Coastal erosion could be reversed 
>on the west side of the present-day Mississippi 
>River. Shrimp, oysters, and other fisheries 
>would probably flourish after a number of years 
>due to new marshes being produced and nutrient 
>rich sediments being redistributed.
>This would obviously place a lot of stress on at 
>least two generations of residents. We would 
>survive, but it would be a new Louisiana and Mississippi River delta.
>1.  Burgess, Richard "Flow to trigger Morganza use"
>      Retrieved 2011-05-10
>2. "Morganza Floodway". US Army Corps of Engineers
>      Retrieved 2011-05-10.
>3.  Weeks, John A.. "Morganza Floodway"
>      Retrieved 2011-05-10
>4.  "Water Over the Levee in Louisiana: 3,000 acres of wheat acres hurt"
>      Midsouth Farmer, April 8, 2008
>      Retrieved 2011-05-10
>5. Old River Control Structure - Louisiana and 
>Mississippi river flood protection - Controlling The River
>     Retrieved 2011-05-10
>6.  McPhee, John "The Control of Nature: Atchafalaya"
>      The New Yorker 1987-02-23
>      Retrieved 2011-05-10

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