PART 1. INTRODUCTION 



The contents of this volume identify largely with procedures for 

 environmental assessment in areas affected by offshore oil and gas 

 recovery operations. In so doing, it lists oil and gas activities 

 and facilities in standard terms, and categorizes them in detail with 

 ecological disturbances and impacts. 



The subject material is simplified by accepting the premise that 

 the principles of environmental assessment are the same whether the 

 issue concerns a permit review, a tract rejection, an evaluation of an 

 environmental impact statement (EIS), or an informal appraisal of poten- 

 tial environmental impacts. 



The material presented is a condensed reference source for eco- 

 logical disturbances, and is structured to serve as a guide for impact 

 assessment. References to a number of interrelated subjects, each of 

 which is explained to the exclusion of other subjects, necessarily 

 require repetitious material throughout Parts 3 and 4. 



The four parts of this report and brief descriptions are as 

 follow: Part I, Introduction ; Part II, Impact Assessment , describes 

 a recommended process for assessing impacts, identifies events that 

 occur in sequence from development to impact, uses standardized nomen- 

 clature for assessment analysis, and recognizes ecological disturb- 

 ances as the key element for assessing impacts; Part III, Generation 

 of Disturbances by OCS Projects , reviews relevant data on ten types 

 of OCS-related projects that may create ecological disturbances (the 

 information is partly drawn from Volumes I and II of this series and 

 the text is organized into project groups); Part IV, Potential 

 Disturbances of Standard Subprojects , provides detailed review of 

 ecological disturbances caused by OCS-related oil and gas development. 

 The 20 subp>"ojects were standardized to avoid extensive repetition 

 regardless of the specific project for which the subproject is proposed. 



Ecological effects of impact assessment are not traced out in 

 detail in this volume because its purpose is to identify the sources of 

 disturbance rather than to trace the effects through to impacts. The 

 underlying assumption is that the reviewer or assessor has sufficient 

 knowledge to predict the sequence from disturbance to effects, and 

 from effects to impacts, after the distrubances are identified. 



