Degree of contamination . This has the same weight in the cleanup de- 

 cision scheme as the biological-cultural sensitivity factor with the same 

 range of relative values (1-9). 



The extent of contamination of a shoreline is dependent upon the type 

 of oil, type of substrate, currents and wind direction, and intensity. The 

 degree of contamination can be assessed by the depth of surface contamination 

 or penetration and extent of coverage for that particular shore. 



For spills that affect inland water courses, stream bank vegetation and 

 debris affects the degree of contamination. In many cases, this material 

 serves as a natural oil absorbent; however, it can also be difficult and time 

 consuming to remove. 



Oil migration . Oil that has contaminated a shoreline may pose a serious 

 threat to other clean shorelines downstream of the affected area. In the case 

 of inland spills, water currents, wind direction, and intensity will affect 

 oil movement. Even oil that may be entrapped can be moved if a wind shift 

 occurs. In a riverine environment with alongshore and currents, oil can be 

 moved from one site to another. 



This factor is one that incorporates the likelihood of change in the 

 physical conditions, namely, the weather. A storm front moving through the 

 spill affected area can change the wind direction, intensify wave action; 

 thereby, moving the oil from one site to another. 



This potential must be evaluated and given a weighted numerical value; 

 = no likelihood for change, 4 = change is imminent. 



Spatial distribution . It is possible that more than one shoreline will 

 be given the same cleanup priority value according to the decision scheme. 

 In this event, the upstream areas should be given priority for cleanup; there- 

 fore, any residual oil lost during removal will be contained at the downstream 

 site. 



Use of the Priority Scheme 



The OSC can use the priority ranking decision scheme (Figure 1), as a 

 guide in selecting when and where he should implement cleanup measures. As 

 conditions change or as new information becomes available, the OSC can use 

 the decision scheme to reorder the cleanup priorities. 



The following are some hypothetical spills that are presented as test 

 cases to illustrate the utility of a decision scheme for generating a 

 priority scheme. 



106 



