MARSH IMPOUNDMENTS FOR THE MANAGEMENT 

 OF WILDLIFE AND PLANTS IN LOUISIANA 



Robert H. Chabreck and George M. Junkin 



School of Forestry, Wildlife and Fisheries 



Louisiana State University Agricultural Center 



Baton Rouge, LA 70803 



ABSTRACT 



Marsh impoundments are widely used in coastal regions for improving wildlife habitat, 

 aquaculture, water storage for agricultural irrigation and industrial uses, the flooding of marshes 

 for mosquito control, and the maintenance of favorable water depths for navigation. Impoundments 

 used to improve wildlife habitat can be categorized into four types by water depth and salinity 

 regimes: permanently flooded with freshwater, manipulated freshwater, permanently flooded with 

 brackish water, and manipulated brackish water. Their effects on wildlife and plants vary with the 

 species involved and the type of impoundment. 



Impoundments have been widely used in Louisiana for waterfowl management. This type of 

 management has been particularly effective in improving marshes for ducks, but habitat for other 

 forms of wildlife is also improved. Marsh impoundments have certain limitations, which at times 

 make it necessary for landowners to use other types of management. First, impoundments are 

 costly to construct and maintain. Also, without facilities for pumping water, years that are 

 unusually wet or dry generally result in poor food production. Impoundments can be built only 

 in areas that will support a continuous levee. In certain areas, such as southeastern Louisiana, 

 impoundment use is limited because of the fluid nature of the subsoil. 



INTRODUCTION 



Marshes along the Louisiana coast occupy approximately 985,000 ha and constitute over 40% 

 of the total marsh area of the gulf and Atlantic coasts (Alexander et al. 1986). One-fourth of 

 the waterfowl in North American use the Louisiana coastal region as winter or transient habitat 

 (Hansen and Hudgin 1966). 



Because of the widespread deterioration of coastal marshes, the rapid inland advancement of 

 saltwater, and the reduction in quality wildlife habitat, marsh management is becoming increasingly 

 important. Impoundments and water management are critical aspects of marsh management and 

 may be necessary to maintain the existing condition of a marsh or to improve the marsh's value 

 as wildlife habitat. 



The term "impoundment" shall be defined as any area of wetland enclosed by an earthen dike 

 in which various types of water-control structures may be installed for draining or flooding the 

 area (Williams 1987). Marsh impoundments are hydrologically isolated and are widely used in 

 coastal regions for improving wildlife habitat, aquaculture, water storage for agricultural irrigation 

 and industrial uses, flooding marshes for mosquito control, and maintaining favorable water depths 

 for navigation. In this paper, we will deal primarily with impoundments for improving wildlife 

 habitat. 



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