Terms have been standardized and are mutually exclusive to the extent 

 possible. 



In addition to constructionand operation, two other types of acti- 

 vities are recognized. First, choosing a location for a facility is an 

 activity that precedes construction but is usually related to a project, 

 not a subproject. Second, designing a subproject also precedes construction. 

 The layout of units within a parcel is considered to be an aspect of design. 



2.2.3 Disturbances and Effects 



Activities that lead to perturbations of the environment, or disturbances , 

 may trigger a complex sequence of effects. The effect series is made up of 

 a number of elements that proceed from one to another and that often interact 

 or feed back. For simplicity. Figure 1 shows only three stages, or orders, of 

 effects. At times the linkage may be longer and more involved. At other 

 times it is simple and the effect series is short-circuited; for example, 

 land clearing (construction activity ) may lead directly to extensive fresh- 

 water dilution of an estuary from rapid stormwater runoff ( disturbance ) and 

 cause salinity reduction ( effect ) which results in a mass death of edible 

 clams ( impact ) or detriment to mankind, the loss of the clam resource, comes 

 from the first-order effect , dilution. 



Usually the sequence of effects that lies between disturbance and impact 

 has more similarity to a web than to a chain because of the interactions and 

 feedbacks. Often a profusion of effects leads directly from a single dis- 

 turbance . Conversely, a number of separate disturbances may multiply a 

 single effect . A typical array of effects is illustrated in Figure 2. 



Table 2. Standard Subprojects for Use in Impact Assessment of OCS-Related 

 Primary and Secondary Development 



Subproject 



Number Subproject Title 



SP-1 Navigational Improvement 



SP-2 Piers 



SP-3 Bulkheads 



SP-4 Beach Stabilization 



SP-5 Site Preparation 



SP-6 Site Development 



SP-7 Artificial Watercourses and Water Bodies 



SP-8 Roadways and Bridges 



SP-9 Groundwater Supply 



SP-10 Sewage Systems 



SP-11 Overland Transmission Systems 



SP-1 2 Stormwater Systems 



SP-1 3 Solid Waste Disposal 



SP-1 4 Industrial Wastewater Systems 



SP-15 Industrial Cooling Water Systems 



SP-16 Pest Control 



SP-1 7 Dikes and Levees 



SP-18 Offshore Platforms and Structures 



SP-19 Marine Transport of Oil 



SP-20 Submerged Transmission Systems 



