Potential diversion of 200,000 to 500,000 acre/ft/yr of water from the Missouri 

 River for a coal slurry pipeline is also rather negligible. Larger diversions for 

 irrigation in the upper Midwest may be more significant but are probably 

 uneconomical unless funded by the Federal Government. 



Rodney Adams: If one colored on a map the areas where the projects discussed may 

 provide some benefits, there would be a large void between the Houma Navigation 

 Canal and the Barataria Waterway and in certain areas in St. Bernard Parish. We 

 need some more critical permitting procedures in these areas where such mitigative 

 approaches are infeasible. 



Martha Landry: Where have the sediments which used to come down the Mississippi 

 River been diverted? 



Raphael Kazmann: Although in the upper Missouri and Arkansas Rivers there are 

 reservoirs which can contain about twice the normal annual flow of the river, 25 

 percent of the reservoir capacity is to be used for storage of sediment. Missouri 

 River water used to have a tremendously high suspended sediment load which has 

 now been greatly reduced. They have not yet designed reservoirs which will allow 

 sediments to effectively bypass containment, although about 10 years ago the Bureau 

 of Reclaimation was optimistic about designing such devices. 



Dag Nummedal: If by design or default the Mississippi was fullydiverted tothe Atchafalaya, 

 what would be the effect on chenier plain progradation? 



John Wells: With 30 percent of the Mississippi River water and sediment flow there is 

 substantial progradation which should accelerate once the Atchafalaya Bay fills. If 

 this increased to 60 percent or more, there would be very rapid effects in about 10 

 years. 



Walter Sikora: The sedimentation phenomena described for the lower Barataria Bay 

 results from reworked sediments in a saline or brackish medium. This may result in 

 more rapid sedimentation from water flowing into the marsh than in the case of 

 freshwater diversions into a marsh. The suspended sediments in the fresher water 

 may settle much more slowly. 



Richard Hatton: When the water flows into the marsh the sheet flow rates are very slow, 

 such that the sediments are deposited after travelling only short distances. 



John Wells: It now appears that the effect of salt flocculation has been overemphasized 

 and that sedimentation by organic binding of fine particles is important both in 

 marine and fresh waters. 



Bob Gerdes: If enough small diversion structures were built along the lower river, would 

 that reduce the pressure on the Old River control structure during floods? 



Raphael Kazmann: They would have no effect because they are too far away, up to 200 

 river miles. Relief spillways must be close. Even the opening of the Morganza 

 spillway, 10 to 12 miles away, during the 1973 flood had less of an effect than 

 expected at the Old River control structure. 



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