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

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) EvaluationTable 5-117 shows that Alternative B4 would not result in any change to the total area of roadways and parking.The majority of the increases in impervious surfaces for Alternative B4 is not from new roadways or parkingareas, but is the result of new runway, taxiway, and building areas. The construction of any new imperviousareas would be designed to meet the 2010 Rhode Island Stormwater Design and Installation Standards Manual andtherefore would not adversely affect water quality. The partial relocation of Airport Road and the relocation ofportions of the Airport service roads in the Mill Cove drainage area, and the 4.5 acres of new roadways andparking areas in the Brush Neck Cove drainage area would not adversely affect downstream water quality andwould reduce potential pollutant loading to receiving Callahan Brook streams.Alternative B4 would decrease the amount of road and parking lot impervious surfaces by 1.0 acres in the BrushNeck Cove watershed, thus improving water quality by removing potential pollutant sources. The 1.0 acreincrease in roadway and parking lot impervious surfaces in the Mill Cove watershed would include mitigationmeasures designed to meet state stormwater requirements and would not adversely affect water quality in thereceiving waters of Buckeye Brook and Warwick Pond.Table 5-117 Alternative B4: Impervious Roadway and Parking Areas by Drainage Area 1Change in Roadway and Parking Area (acres) 2Voluntary LandNo-Action Required for AcquisitionDrainage Area Alternative Alternative B4 Construction 3 Areas 4 TotalBuckeye Brook North 106.8 106.8 0.0 0.0 0.0Warwick Pond 0.8 0.8 0.0 0.0 0.0Buckeye Brook South 50.5 51.5 +1.0 0.0 +1.0Mill Cove (cumulative) 5 158.1 159.1 +1.0 0.0 +1.0Tuscatucket Brook 21.0 18.5 (4.0) +1.5 (2.5)Callahan Brook 19.1 20.6 (0.5) +2.0 +1.5Brush Neck Cove (cumulative) 6 40.1 39.1 (4.5) +3.5 (1.0)Total 198.2 198.2 (3.5) +3.5 0.0Source: VHB, Inc.1 The areas in this table represent the portions of the watersheds that fall within the maximum combined footprint of the Alternatives (including both on- andoff-Airport areas). Totals are rounded. Existing roadways were assumed to remain impervious.2 The roadway and parking areas are a subset of the impervious areas referred to in Table 5-116 (e.g., 198.2 acres of the 539.8 acres total impervious acres areattributed to parking and roadway surfaces).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 5-118 shows that Alternative B4 would result in a 0.9 percent increase to the total pollutant load whencompared to the No-Action Alternative. Infiltrating stormwater BMPs and pervious surfaces located betweenimpervious surfaces (taxiways and runways) and the stormwater collection system would effectively mitigatepollutant loading impacts in receiving waters of Spring Green Pond, Buckeye Brook, and Warwick Pond.Chapter 5 - Environmental Consequences 5-218 July 2011\\mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH05_Environmental_Cons_JUL_2011.doc