Different large-scale factors frequently confound management problems. 

 Man-induced or natural phenomena that occur off the refuge or over an entire 

 region (part of which is occupied by the refuge) are constantly interacting 

 with the ecosystems found on the refuge. Examples include the Gulf Intracoastal 

 Waterway, channelization of the Mississippi River and other shipping lanes, 

 large-scale subsidence, periodic fires, periodic flooding, and altered sediment 

 and river-water input. Such features are affected by, and have influence on, 

 the petroleum exploration and extraction processes. 



Thus, the existence per se of a maze of canals and/or levees in a given 

 wetland area represents a loss of land habitat. More important, by providing 

 a route of intrusion, it makes possible an additional impact - complete ecosys- 

 tem conversion. The Sabine NWR is one example of such a situation. The 

 waters of Sabine and Calcasieu Lakes became increasingly saline due to channeli- 

 zation of shipping lanes. The existing network of canals on the refuge provides 

 an open passage for these waters into and through most parts of the refuge. 

 Areas that were fresh marsh are now brackish marsh. The Delta NWR is another 

 case where primary focus must be on regional phenomena. Any alteration which 

 serves to isolate the "inner ponds" of the delta accelerates the loss of 

 subaerial land habitat. The rate of subsidence in this area is great; there- 

 fore the existence of the delta ecosystem is dependent upon periodic flooding 

 and its concomitant deposition of new sediments. 



These regional phenomena cannot be completely controlled. Management 

 must face the situation and make intermittent (sometimes daily) decisions 

 concerning petroleum activities. It appears that an optimum strategy would be 

 to consider and categorize all pertinent phenomena, commencing with long-term 

 regional types and ranging downward through the ecosystems, culminating in 

 specific sites of concern. These long-term phenomena, along with the goals of 

 the particular refuge, must be kept in the foreground as periodic management 

 decisions are made. 



In regard to regulations and stipulations, this usually translates into: 



(1) minimizing total habitat losses during each phase of petroleum activities, 



(2) maintaining adequate major water flows for the particular wetland ecosystem, 

 and (3) providing for restoration of landforms and conditions after petroleum 

 operations have terminated. 



The first category, minimizing habitat loss, can be attained by encouraging 

 preferred methodologies: the push method of pipeline installation, double 

 ditching techniques, directional drilling, and revegetation. Standardization 

 of maximum dimensions would also be helpful for management. 



The second category, maintaining water flows, requires knowledge of the 

 water regimes of the entire region, ecosystem, and refuge. Without information 

 concerning sheetflow and drainage of specific sites on the refuge, risk-laden 

 decisions must be made. In planning for maintenance of existing water flows. 



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