T.F. Green Airport Improvement Program - FEIS Chapters - PVD

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) Evaluation6.21.8 Wetlands and WaterwaysThe DEIS included 11 conceptual wetland mitigation sites to compensate for unavoidable losses of 7.8 acres ofwetlands associated with Alternative B2 airport enhancements to Runway 23 and Runway 34. Wetland impactsassociated with safety enhancements to Runway 34 (including the relocation of Taxiway C, extension ofRunway 23 north across Airport Road, the relocation of the AMF access drive, and the full relocation of AirportRoad) have been subsequently reduced to 5.8 acres. Unlike the Preferred Alternative, Alternative B2 woulddirectly impact Buckeye Brook and Wetland A5 immediately adjacent to the brook and would therefore involvethe loss of a greater array of wetland functions and values. The wetland impacts associated with Alternative B2are listed below and presented in Table 6-19. 496• 5.6 acres of wetlands providing a groundwater discharge function,• 2.9 acres of wetlands providing flood storage at the principal level,• 2.0 acres and 2.1 acres of wetlands providing sediment/toxicant/pollutant removal and nutrientremoval/retention/transformation, at the principal level, respectively,• 5.6 acres of wetlands providing groundwater recharge and discharge function,• 1.7 acres of wetlands providing a production export function,• 0.1 acres of wetlands providing sediment/shoreline stabilization,• 1.7 acres of wetlands providing fish and shellfish habitat function mostly at the principal level,• 3.8 acres of wetlands providing a wetland wildlife habitat function mostly at the principal level,• 0.2 acres of wetlands providing recreational value, and• 1.7 acres of wetlands with uniqueness/heritage value.Table 6-19Alternative B2: Wetland Functions and Values Impacted (acres)Program GWR/D- S/T/P R- NR/R/T- WLH- T&E U/H- VQ/A Element SWGW FFA WQ WQ PE S&S S F&SH WWH SH REC AES AESRunway 34 5.6 2.9 2.0 2.1 1.7 0.1 1.7 3.8 - 0.2 1.7X.X Principal Wetland Function or Value. S&S S Sediment and Shoreline Stabilization.X.X Additional Wetland Function or Value likely provided by wetland. F&SH Fish and Shellfish Habitat.GWR/D Groundwater Recharge/Discharge. WLH Wildlife Habitat.SWGW Surface Water and Groundwater. WWH Wildlife and Wildlife Habitat.FFA Floodflow Alteration. T&E SH Threatened and Endangered Species Habitat.S/T/P R Sediment/Toxicant/Pathogen Retention. REC Recreation.NR/R/T Nutrient Removal/Retention/Transformation. ED/SV Educational/Scientific Value.WQ Water Quality. U/H Uniqueness/Heritage.PE Production Export. AES Aesthetic.VQ/A Visual Quality/Aesthetics.As shown in Tables 6-19 and 6-20, Alternative B2 would have greater impacts to wetlands than Alternative B4and would therefore require more acres of wetland mitigation and more wetland mitigation sites.Alternative B2 would impact 5.8 acres of wetland, 5.2 acres of which are within the Buckeye Brook watershed.Except for the wetland creation/restoration proposed at Mitigation Sites 5 and 7, and preservation proposed at496 Alternative B2 would impact 1.8 acres of emergent wetland (0.4 acres is dominated by the invasive common reed), 0.6 acres scrub-shrub, and 3.4 acresforested wetland.Chapter 6 – Mitigation 6-48 July 2011\\Mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH06_Mitigation_JUL_2011.doc