conversion of these wetlands to more saline types will adversely affect nnigratory puddle 

 ducks, OS relative abundance of these waterfowl in the LCR is highest in the fresher 

 marsh types (Palmisano 1973). Based on rather conservative projections of declines in 

 habitat quality and abundance in the LCR, it has been estimated that demand for 

 waterfowl hunting will exceed available supply by 454,000 man-days by the year 2020 

 (U.S. Fish and Wildlife Service 1976). Habitat quality and quantity for other marsh birds 

 such as rails, gallinules, American coot, and various wading birds will also be reduced by 

 continued wetland deterioration. Nutria comprised roughly 70% of Louisiana's total fur 

 harvest between 1970 and 1975 (O'Neil and Linscombe 1975). Nutria catch per acre is 

 highest in fresh marsh, declining progressively in the intermediate, brackish, and saline 

 marsh types (Palmisano 1973). 



Alligator populations also reached peak levels in fresh to intermediate marshes 

 (McNease and Joanen 1978). Accordingly, continued wetland deterioration can be 

 expected to result in declines in fur harvest and alligator populations, especially as land 

 loss and saltwater intrusion reduce fresher marsh acreage. 



DISCUSSION OF MEASURES TO REDUCE WETLAND DETERIORATION 



Except for regulation of development, the primary measures investigated to date 

 for control of wetland deterioration in the LCR have involved diversion of Mississippi 

 River water into adjacent marshes and estuarine areas for salinity control and creation 

 of new subdeltas. A plan for introduction of Mississippi River water into the subdelta 

 marshes of southeast Louisiana was submitted by the Fish and Wildlife Service to the 

 U.S. Army Corps of Engineers in 1959 (U.S. Fish and Wildlife Service 1959). This plan 

 included a recommendation for the construction of four water control structures, having 

 a combined discharge capacity of 620 m-^/sec (24,000 cfs), to divert Mississippi River 

 water for salinity control. The structures would have benefited an estimated 107,000 ha 

 (264,500 acres) of marsh and estuarine waters. The annual benefits of this plan in 

 increased oyster yields, furbearer harvest, and waterfowl utilization were estimated at 

 $841,600, exceeding costs by 62%. That plan, now known as the "Mississippi Delta 

 Region, Louisiana" project, was authorized by Public Law 89-298 on 27 October 1965. 

 Detailed planning of one of the four authorized diversion structures was initiated in 1969, 

 but was suspended when local interests failed to furnish economic justification for their 

 requested change in the location of that structure (U.S. Army Corps of Engineers 1975). 

 It should be noted that, despite the obvious need for the project to mitigate the adverse 

 effects of the Mississippi River mainline levees, the project is classified as 

 "enhancement", making local Interests responsible for 25% of the project costs. This has 

 been cited by local interests as one reason for their reluctance to participate in the 

 project. Now there is renewed local Interest, however, in one of the four diversion 

 structures (Caernarvon site), and a new letter of assurance is reportedly forthcoming 

 from the State of Louisiana to the Corps of Engineers indicating a willingness to assume 

 25% of the project cost. The most comprehensive treatment of measures for arresting 

 land loss and saltwater intrusion in the LCR is contained In a report prepared by Gagliano 

 et al. (1973b) under contract to the U.S. Army Corps of Engineers. That study was 

 conducted in conjunction with a broad evaluation of the LCR by on ad hoc interagency 

 group and evaluated two primary measures for addressing wetland deterioration, 

 including: 



(I) controlled introduction of Mississippi River water into adjacent estuarine 

 marshes and bays for salinity control and nutrient input; and 



103 



