Notes
Exhibit 175 (AR018443) summarizes wetland mitigation credit for Sea-Tac Airport Master Plan Update improvements. Tables detail in-basin mitigation (102.27 acres, 29.80 credit) and out-of-basin mitigation (65.38 acres, 42.91 credit) for a total of 167.65 acres and 72.71 mitigation credits. Specific mitigation sites include Vacca Farm, Miller Creek Wetland and Riparian Buffer, Tyee Valley Golf Course, Des Moines Creek Buffer, Lora Lake, Borrow Area 3, and West Branch Des Moines Creek Buffer. Credit ratios applied: wetland restoration 1:1, wetland enhancement 1:2, buffer enhancement 1:5, preservation 1:10. Out-of-basin wetland creation includes forest (17.20 acres), shrub (6.0 acres), emergent (6.20 acres), and open water (0.60 acres). In-basin mitigation provides a 5:1 aerial replacement ratio for 18.37 acres permanent plus 2.05 acres temporary wetland impact.