Existing evidence suggests that the indirect impact of canals and spoil banks is both local and 

 regional and is a major contributor to coastal erosion (Figure 1). 



Project Outline 



It is the purpose of a research program at Louisiana State University (LSU) to establish a large- 

 scale experimental study of wetland hydrology to be followed over 10-20 years in direct cooperation 

 with landowners. In addition to smaller studies currently underway, planned new study sites would 

 be composed of at least 15, 2-ha impoundments fitted with adjustable water control devices. 

 Variability in waterflow, soil, plants, and animals will be determined. The only comparable large- 

 scale wetland manipulations we know of are at the Delta Waterfowl and Wetland Research Station, 

 Portage la Prairie, Manitoba. 



Wetlands, by virtue of their hydrologic couplings with the estuary, must be impounded in a 

 large way for researchers and managers to efficiently study mass-balance exchanges, to minimize 

 hydrologic disturbances at the edge, and to study component parts which move over large areas 

 in small numbers and high variability (e.g., waterflow, muskrats, and fish larvae). Despite the 

 need for large-scale study sites, there are no replicated experimental studies which purposefully 

 address the long-term implications of hydrologic alterations of Louisiana marshes. Truly long-term 

 environmental study sites in the United States number less than a dozen. In this study we plan 

 to build several large impounded wetlands (2 ha each) and develop management practices which 

 will have a positive long-term impact on marsh management goals, especially goals to reduce coastal 

 landloss and to learn about wetland ecology. It is our opinion that the most efficient way to 

 proceed is with large-scale experimental study designs which are followed over 10-20 years in direct 

 cooperation with landowners who have an obvious interest in the results. 



co 



co 



CO 

 CD 



600 1 200 



Area of Canals (ha) 



Figure 1. The relationship between the net ureal gain in ponds less than 60 ha formed between 

 1955-1978 and canal surface area (ha) for the 7-1/2 minute quadrangle maps in three areas of 

 the coastal region: (1) St Bernard, a former delta of the Mississippi River, on the eastern 

 border of that river; (2) Barataria, the hydrologic unit just west of the Mississippi River; and 

 (3) Terrebonne, the hydrologic unit on the western border of the Barataria hydrologic unit 

 Adapted from Turner and Rao (In press). 



347 



