EXPERIMENTAL MARSH MANAGEMENT IMPOUNDMENTS 



R.E. Turner, J.H. Cowan, Jr., LA Mendelssohn, G.W. Peterson, 

 R.F. Shaw, C. Swarzenski, and E.M. Swenson 



Center for Wetland Resources 



Louisiana State University 



Baton Rouge, LA 70803 



ABSTRACT 



Although most of the problems of wetland management are coupled to hydrologic changes and 

 hydrologic manipulations are the main management tool, there are no long-term experimental 

 studies of water regulation schemes for controlling landloss rates and managing fish, fowl, and fur. 

 Some of these changes take years to develop and perhaps reflect long-term variations in water 

 level and water quality. Experimental marshes have been constructed in various wetlands (salt- 

 brackish and intermediate-fresh) and are being used to test the effects of water management on 

 vegetation, soils and water chemistry. The objectives are to (1) establish and run long-term, 

 experimental research areas to develop best marsh management practices (a large land-holding 

 company will donate land, and funding is being sought for the dredging expenses of building the 

 impoundments and for one piece of equipment); (2) encourage coordinated research, develop 

 further funding, and regulate access and disturbance to the experimental study area; and, (3) work 

 with coastal landowners to better manage these wetlands for the long-term. Our emphasis is on 

 ecosystem studies involving Sea Grant funded studies of plant and soil properties, hydrology, and 

 fish and wildlife use. 



INTRODUCTION 



It is our purpose here to describe a major research initiative at Louisiana State University on 

 wetland hydrology and wetland management, the reasons for the project, what the project intends 

 to accomplish, and the limitations. 



Hydrologic Change: Direct and Indirect 



Hydrologic manipulations are perhaps the only manageable causal agent of change leading to the 

 high wetland loss and habitat changes observed in Louisiana. If there is a possibility for reversing 

 habitat changes, including wetland to water conversions, then hydrologic alterations are likely to 

 be involved. Existing active or direct management measures include annually or seasonally adjusting 

 water levels using weirs, flap gates, earthen plug, and levees. Several extensive water level 

 management schemes are employed on some refuges with mixed success, but are generally too 

 expensive for use on the vast majority of non-refuge wetlands. There are, however, no 

 experimental studies of how different management measures, proposed for different ends and 

 affecting a common resource, affect the long-term stability of the marsh and animals using it. 

 When management has been intentional, the faunal elements have been managed under a "fish, 

 fowl, or fur" scheme with mixed success, if evaluated at all. This is not a criticism of the present 

 management; it is an evaluation of what we do not know and need to know as the coastal landloss 

 and management problems continue. 



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