SUMMARY COMMENTS OF PANEL MODERATORS 



CAUSES: CHANGES IN DISPERSAL OF FRESH WATER AND SEDIMENTS 



Mr. Gerald G. Bordelon, Chairman, Louisiana Coastal Commission 



The various alterations which man has made to Louisiana's coastal environment for 

 flood protection, navigation, and mineral resource extraction have had many 

 consequences which were not perceived when they were undertaken. This has largely 

 resulted from interruptions of the natural flow of water and sediment on which our 

 estuarine and coastal areas depend. 



The most pervasive alterations have been the control of the Mississippi River flow. 

 Including impoundments up in the watershed, which have reduced to half the previous 

 sediment load of the lower river; leveeing of the river for flood protection, which has 

 prevented the flux of sediments and fresh water in the interdistributary basins adjacent 

 to active delta lobes; and regulated division of the river between the Atchafalaya River 

 and the Mississippi River proper. Over the years, we have also taken various steps to 

 control the coastline Itself, such as jetties and seawalls, some of which we now discover 

 have had some serious negative consequences. All of these alterations have been made 

 to benefit mankind, but now we find that there are also eventual human costs as well. At 

 the same time, nature takes its course, where It takes away it can also give, as in the 

 case of the rapid progradatlon of the Atchafalaya River delta and the chenier plain 

 coast. 



The coastal wetlands of Louisiana need good supplies of fresh water and sediments 

 to maintain their integrety and vitality. We have seen in presentations and discussions, 

 that marshes need a continued sediment supply to offset subsidence and sea-level rise. 

 This is a particularly profound observation, given the possibility of increased sea-level 

 rise in the future. Furthermore, wetlands and estuaries need fresh water, literally the 

 life blood of Louisiana. Fresh waters carry sediments and nutrients, but are particularly 

 needed to maintain the salinity gradients In the estuaries. Saltwater intrusion has caused 

 serious problems for the oyster industry and has caused rapid deterioration of freshwater 

 wetlands. 



Various approaches have been discussed to deal with the problem of restoring fresh 

 water and sediment supplies to our coastal areas. These range from river diversions of 

 various scales, either for maintenance of salinity levels or wetlands accretion, to 

 management of the Atchafalaya delta to maximize the creation of productive habitats, 

 and to nourishment of sand-starved barrier Islands. Although the panelists and audience 

 differed widely in their preferred approaches, all seemed to agree that whatever Is done 

 should be In concert with natural processes rather than in vain attempts to defeat them. 



In summary, natural processes exacerbated by alterations to freshwater and 

 sediment flows have caused major problems which have such significant consequences 

 that we as a society must challenge them. It appears that we need to take Immediate 

 action on a number of necessary long-range plans and accomplish the societal 

 adjustments which will be required. 



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