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

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) Evaluation5.11.4.2 Alternative B2This section describes the direct and indirect impacts that would occur under Alternative B2. Table 5-112 showsthe changes in impervious area within the affected drainage areas. This analysis has been revised since the DEISand now assumes that the existing roadways will not be removed within the acquisition areas with the exceptionof roadways that are to be relocated, such as Airport Road, or are physically impacted by the ImprovementProgram. Compared to the No-Action Alternative, Alternative B2 would increase the total impervious area by79.9 acres, of which the majority is split among the Buckeye Brook North drainage area (32.0 acres caused by thefully relocated Airport Road, the new taxiways, and Integrated Cargo areas), Buckeye Brook South drainage area(35.0 acres caused by the Runway 16-34 RSA enhancements, the reconfigured taxiways, and the south service area)and the Tuscatucket Brook watershed (13.4 acres caused by the Runway 5-23 extension). The increases would bepartially offset by decreases due to removing commercial and residential parking lots required for construction forPartially Relocated Airport Road. The Alternative B2 would include stormwater controls that will managedischarges to Warwick Pond, Buckeye Brook North, Buckeye Brook South, and Tuscatucket Brook and will limitpeak flows and erosion at the outfalls and in the downstream reaches of these brooks. In addition, CallahanBrook will have reduced overall peak flow due to the decreased impervious area in the watershed.Table 5-112 Impervious Surfaces by Drainage Area (Alternative B2)Impervious Area (acres) 1 Alternative B2 Change in Impervious Area 2Drainage Area No-Action Alternative B2Required forConstruction 3Voluntary LandAcquisition Areas 4 TotalBuckeye Brook North 236.9 268.9 +33.5 (1.5) +32.0Warwick Pond 11.7 12.6 +0.9 0 +0.9Buckeye Brook South 161.6 196.6 +35.0 0 +35.0Mill Cove (cumulative) 5 410.3 478.1 +65.3 (1.5) +67.8Tuscatucket Brook 35.0 48.4 +13.4 0 +13.4Callahan Brook 24.3 22.9 0 (1.4) (1.4)Brush Neck Cove (cumulative) 6 59.3 71.3 +13.4 (1.4) +12.0Total 469.6 549.4 +78.7 (2.9) +79.9Source: VHB, Inc.1 Portions of the watersheds that fall within the maximum combined footprint of the Alternatives (including both on- and off-Airport areas). 2 Includes existing pavement, proposed pavement, and impervious surfaces from land acquisitions. Existing roadways were assumed to remain impervious.3 Construction elements include EMAS, parking, roadways, taxiways, and RSA and RPZ clearing, depending on drainage area.4 Associated with the Completed and Current Part 150 VLAP.5 The Mill Cove drainage area consists of the combined Buckeye Brook North, Warwick Pond, and Buckeye Brook South drainage areas evaluated in this analysis.6 The Brush Neck Cove drainage area consists of the combined Tuscatucket Brook and Callahan Brook drainage areas evaluated in this analysis.Table 5-113 shows that Alternative B2 would result in a 17.8-acre increase to the total area of roadways andparking, however, all new roadway and parking areas would include mitigation measures designed to meetstate stormwater requirements and would not adversely affect water quality.Chapter 5 - Environmental Consequences 5-214 July 2011\\mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH05_Environmental_Cons_JUL_2011.doc