1. (1) The purpose of this section is to describe the method of ranking vulnerability of marine and estuarine environments, excluding the Columbia River estuary environment to oil spills for the purposes of assessing damages using the compensation schedule.
2. (2) Marine and estuarine waters of the state excluding the Columbia River estuary are divided into sixteen regions and one hundred thirty-one subregions for purposes of RCW 90.48.366, as designated on the maps attached as Appendix 5 of this chapter.

3. (3) A spill vulnerability score (SVS) shall be calculated at the time of a spill for the most sensitive subregion and season impacted by the spill. The SVS rates the vulnerability of public resources to spilled oil based on the propensity of the oil to cause acute toxicity and mechanical injury, and to persist in the environment. SVS is determined by summing the vulnerability scores for marine birds, marine mammals, fishery species, recreational use and habitats for the subregion(s) and most sensitive season impacted by the spill. The formula to be used to calculate SVS for each of the three oil effects, acute toxicity, mechanical injury, and persistence, is as follows:

   Spill vulnerability score (SVS)_ij=

   HVS_i + BVS_j + MVS_j + MFVS_j + SFVS_j + SAVS_j + RVS_j

   where	HVSi = habitat vulnerability to oil's propensity to cause i
   	BVS = marine bird vulnerability score (WAC 173-183-420(3));
   	MVS = marine mammal vulnerability score (WAC 173-183-460(3));
   	MFVS = marine fisheries vulnerability score (WAC 173-183-430(3));
   	SFVS = shellfish vulnerability score (WAC 173-183-440(3));
   	SAVS = salmon vulnerability score (WAC 173-183-450(5));
   	RVS = recreation vulnerability score (WAC 173-183-470(3));
   	i = acute toxicity (AT), mechanical injury (MI), or persistence (PER); and
   	j = the most sensitive season affected by the spill: Spring, summer, fall, or winter

[Statutory Authority: RCW 90.48.366, 90.56.050, 90.48.035. WSR 13-01-055 (Order 11-05), § 173-183-400, filed 12/14/12, effective 1/14/13. Statutory Authority: Chapter 90.48 RCW. WSR 92-10-005 (Order 91-13), § 173-183-400, filed 4/23/92, effective 5/24/92.]