2.6 Creation of pathways for increased rate of flow of runoff 

 (buggy tracks and/or backfilled canals) 



2.7 Blockage or alteration of existing tidal drainage pattern 



2.8 Change in frequency of inundation in localized areas (buggy 

 tracks and/or backfilled canals) 



3. Attribute alterations 



The alterations associated with line installation and maintenance in 

 a salt marsh vary widely and depend primarily upon the type and size 

 of pipeline. 



Supply lines and flowlines laid on or parallel to an access road or 

 canal generally have less impact than those traversing unaltered 

 marsh. The movement of work crews and marsh buggies over the land 

 surface tramples and crushes vegetation. Depending upon the soil 

 moisture conditions, the vegetation may be completely uprooted and 

 destroyed in some areas. This results in an immediate decrease in 

 food and cover for the consumers in the area. The total area thus 

 affected is usually small in comparison to the remaining area of 

 productive vegetation, and the effects on animals, nitrogen fixa- 

 tion, and detritus export are insignificant. 



The depth and number of ruts created by marsh buggies is dependent 

 upon the number of vehicles and the degree to which they retrace 

 existing tracks. In areas that are submerged daily, the depressions 

 are less likely to significantly alter water-movement patterns. 

 Hence, in areas near the estuary, confinement of marsh buggy traffic 

 to a narrow corridor may be wise. However, in areas further removed 

 from the estuary, deep ruts resulting from retraced trails would 

 form a depression for the movement of water and, if deep enough, may 

 result in standing bodies of water after the tide has receded. The 

 orientation and depth of the depressions determine whether they (1) 

 remain for long periods of time and (2) increase or decrease the 

 frequency of inundation of a given area of land. Areas dominated by 

 saltgrass or shore grass may be replaced by stands of smooth cordgrass 

 when the frequency and/or duration of inundation increases. The 

 converse may occur when frequency and/or duration of inundation 

 decreases. The total area affected is site specific and could range 

 from insignificant to highly significant when compared to the total 

 area of salt marsh. Consumers that depend upon smooth cordgrass and 

 its epiphytes for food and/or cover may ultimately increase or 

 decrease. 



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