Brine may be introduced into the marsh unintentionally as a result of 

 leakage from flowlines or storage facilities. Although plants and 

 animals of the salt marsh can withstand salinities of up to 40 ppt, 

 freshwater species are intolerant of saline conditions. Introduction of 

 brine of high or even moderate salt concentration (and unnatural ion 

 distribution) stresses fresh marsh species to a point where survival is 

 not possible. Larval and juvenile stages of aquatic vertebrates, and 

 most aquatic invertebrate forms, are particularly affected by saline 

 water influxes; death or stunted growth may occur. Much of the impact of 

 brine effluent depends upon duration of discharge, quantity released, 

 brine concentration, brine temperature, and dilution factors. Though 

 some species may be able to tolerate moderate salinities, tolerance does 

 not last long under such stressed conditions. The salinity tolerances of 

 most species decreases with increased brine temperatures. In situa- 

 tions where chronic discharge is prevalent, fresh marsh species may be 

 replaced by more tolerant brackish marsh flora. Such changes, however, 

 would likely occur only in localized areas. 



Routine maintenance operations require regular visits to the complex. If 

 access is accomplished over leveed roads, temporary increases of dust and 

 sediment can result. If equipment monitoring, maintenance, and repair 

 require the use of boats, water turbidity increases within the access 

 canal banks. The extent of this increase depends upon the frequency of 

 boat passage, boat size and speed, and canal dimensions. Continued high 

 turbidity levels may inhibit phytoplankton and submergent plant produc- 

 tivity levels within canals. 



Ordinarily the effect of facility placement on waterflow patterns is 

 minor compared to the existing hydrologic alterations caused during site- 

 access phases. The small processing complex is but a minor component of 

 a much larger alteration-generating process. The pad itself may cause 

 restricted changes in water depth, water inflow, and turnover, which 

 subsequently cause localized changes in plant composition, but such events 

 are of minor consequences at the ecosystem level of consideration. 



Disturbances associated with road or canal construction, drilling and 

 operational activities, vehicular traffic, human presence, and noise 

 initially cause short-term wildlife displacement. Displacement may 

 become permanent if the wellsite or unmodified marsh is prepared for 

 long-term production (sometimes several decades in duration). Nearby 

 nesting, foraging, and escape cover may be degraded by the proximity of 

 continuous human activity and operational procedures. Sensitive wildlife 

 species may avoid otherwise favorable habitats because of human intrusion 

 into formerly undisturbed environments. Notable examples are abandonment 

 of nesting rookeries by wading and shorebirds and reduced use of favored 

 feeding areas by waterfowl. The magnitude of such displacement is diffi- 

 cult to quantify, especially since species have differing sensitivities 

 to disturbance. However, it should be recognized as an important consi- 

 deration which extends project impacts beyond the boundaries of the 

 immediate site for a long period of time. 



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