The flushing rate (movement of fresh water from wetlands 

 into bayous and to the Gulf) increases when north-south 

 bayous are straightened and deepened. This results because 

 the water does not have time to unload sediment and nutrients 

 in the wetland area. The faster movement of water in the 

 bayous and canals also causes erosion along the unstable 

 banks of the streams. Other channels that are dug east-west 

 across the marsh create spoil banks that interrupt the 

 normal north-south sheet-like flow of water. This flow of 

 water is important because it disperses nutrients and 



detritus over the wetlands. Additionally, man-made channels 

 disrupt nursery areas of many commercially important marine 

 animals (e.g., shrimp and menhaden). Dredging and channeling 

 for the building of oil wells and pipelines can often 

 destroy vegetation and habitats of marsh animals. (See 

 Mumphrey et al . (1975: 86-89) for a more complete discussion.) 

 Burying pipelines and the revegetation of their paths through 

 the marshes mitigates but does not eliminate the effects of 

 the associated channels (Willingham et_al. , 1974). Also, 

 creative dispersal of spoil banks can mitigate some of the 

 effects of channelization. 



Where deep, straight canals are cut, salt wedges can 

 result and extend far inland, causing the death of vegetation 

 which results in the loss of nutrients, habitat, and erosion 



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