other impervious linings. Water infiltration rates are reduced by 

 losses of soil porosity, thereby decreasing soil moisture and water 

 percolation through the soil. Surface-water runoff, intensified by 

 compacted nonporous soils, lack of vegetative cover and increased 

 pad slopes and elevation, increases the erosional transport of 

 sediments and nutrients into adjacent areas. Sediment transport is 

 typically very localized in the coastal upland sites because of 

 little topographic relief or slope and more porous soils enclosing 

 the activity site. Large-scale upland effects at the ecosystem 

 level are of minor consequence. Sediment and nutrient transport 

 into adjacent wetlands or streams, however, is of greater concern as 

 sediment introduction may cause significant system changes. Analy- 

 sis, therefore, requires treatment through the appropriate aquatic 

 ecological system. Other soil structure aspects include soil 

 moisture and soil aeration linkages to the flora; groundwater 

 recharge, percolation, infiltration, and water-holding capacity 

 linkages to the hydrosphere; and evaporation pathways to the atmos- 

 phere. Even though seriously altered on the site (usually reduced), 

 these aspects are not considered for further analysis because (1) 

 biotic effects are not relevant since plant and animal recovery is 

 precluded by operational activities, or (2) the comparative effects 

 from a single small site on the ecosystem's hydrologic or atmospheric 

 regimes are considered to be very minor. 



Production facility construction may disrupt existing surface hydrol- 

 ogy by obstructing or filling intermittent drainages and shallow 

 depressions. Site placement in marshes or small ponds is treated in 

 the discussions of the marsh ecosystems. Drainage blocking may 

 result in temporary ponding of the upper drainage and an increase in 

 the macropore water storage. Site buildup in moist upland areas 

 increases the zone of aeration in the soil. Either alteration may 

 cause a local change in the existing soil air and soil moisture 

 regime such that the existing floristic assemblages are replaced by 

 species favored by the new equilibrium conditions. Dependent 

 consumer groups may change accordingly, depending upon the areal 

 extent of the alteration. Typically, however, the effects will 

 probably be localized and result in no fundamental ecosystem 

 changes. 



Small-scale releases of toxic substances inevitably occur at the 

 complex in spite of the preventive and maintenance procedures insti- 

 tuted. Ecological alterations associated with larger spills and 

 cleanup are treated as a separate section of this discussion. 

 Specific data documenting the ecological effects of toxic chemical 

 discharge into upland communities are very sparse in the literature. 

 However, soil salinity, which restricts or prohibits vegetative 

 growth, can be increased by seepage of oil field brine. It is 

 expected that ecological alterations as a result of normal opera- 

 tional procedures are very restricted in areal extent due to the 

 low-volume discharge and limited lateral mobility of substances 

 through soil strata. Local biotic effects are a function of the 

 substance's toxicity, quantity released, mobility through the food 



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