restoration procedures as is required by Federal and state regulations, 

 lease stipulations, and general company policy. Typically, restoration 

 includes removing or burying toxic substances, refilling all pits, knock- 

 ing down interior earthen levees, an., generally leveling the site. 

 Original site contours may be reestablished. Natural processes are 

 usually relied upon to reestablish ground cover. If revegetation is con- 

 ducted, commercially available seeds of hardy wery adaptable grasses, 

 such as bermuda grass, are sown on disturbed soils. Fertilization, 

 mulching, and final top dressing may occur. Vehicles generally exit 

 after distributing the seed and dressing the site. The site restoration 

 procedure is normally not a '^ery extensive operation on the levee system. 



Access canals that are cut through natural or artificial levees are 

 refilled only on rare occasions after they cease to be used. Because of 

 bank erosion, compaction and subsidence, there is rarely enough material 

 on site to repair them. However levees are often repaired by reinforced 

 plugs when canals are taken out of active service. 



2. Primary ecological alterations 



2.1 Increase in soil structure due to grading, filling, and plowing 



2.2 Decrease in soil toxicants due to removal of oil-, brine-, and mud- 

 contaminated soils 



2.3 Increase in available nutrients with fertilization 



2.4 Increased producer biomass by reseeding or replanting 

 Attribute alterations 



Procedures that reestablish soil structure damage by previous construc- 

 tion and operational activities are most beneficial; soil air concentra- 

 tions increase because of improved soil porosity, thereby enhancing the 

 soil environment for plant establishment. Soil moisture not only 

 provides necessary water for the plant, but it also moderates the extreme 

 effects of soil heat and soil salt content. These two aspects are 

 thought to be of minor importance, however. 



Replacement of leached and eroded nutrients through fertilization and 

 removal of toxic soil materials (brine, petrochemical wastes, and dril- 

 ling substances) speed natural recovery processes, enabling establishment 

 of more complex plant assemblages without requiring preceding serai 

 stages to develop necessary soil conditions. Fertilization has the 

 greatest petential for long-term benefits by improving soil structure. 



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