PART 2. IMPACT ASSESSMENT 



Standardized procedures and nomenclature for impact assessments 

 are invaluable for effective environmental analysis. A relatively 

 sophisticated and useful method for determining oil and gas activity 

 impacts is described here in detail and incorporates considerable 

 information and terms developed in other volumes of this series. 

 Although the method of impact prediction given here seems relatively 

 complicated, careful examination of this section is likely to demon- 

 strate that the method is relatively simple and highly useful, and 

 is predicated on clearly evident elements in a framework of human 

 activities and environmental impacts. 



2.1 IMPACT TERMS AND CONCEPTS 



To reduce misunderstanding and provide clarity, the elements of 

 oil and gas activities and environmental analysis are categorized into 

 a standard set of terms. These terms are explained in some of the 

 following sections and those used in Part 2 of the text are usually 

 underlined to eliminate need for further interpretation. 



2.1.1 The Impact Cycle 



The standard elements of impact assessment are linked in a change 

 of causes and effects that starts with human needs and, at the end of 

 the cycle, returns to human needs (Figure 1). The workings of the 

 cycle become more apparent later in Part 2. The needs result in programs 

 which lead to the initiation of specific development projects . These 



Figure 1. An impact cycle, based on human needs, describing pathways 

 of cause and effect. 



CAUSAL SERIES 



HUMAN NEEDS 



r 



PROGRAM 



EFFECTS SERIES 

 ' 



ENVIRONMENTAL 

 IMPACT 



PROJECT 



(AND SUBPROJECTS) 



CONSTRUCTION 

 ACTIVITY 



OPERATIONS 

 ACTIVITY 



a 



ENVIRONMENTAL 

 DISTURBANCE 



3° EFFECT 



2° EFFECT 



1° EFFECT 



T 



