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

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) Evaluationfield-inspected to collect descriptive data used to classify and evaluate the wetland. The evaluation of wetlandfunctions and values follows the "Descriptive Approach” provided in the USACE Highway MethodologyWorkbook Supplement. 216 The Highway Methodology Workbook Supplement recognizes thirteen wetland functionsand values. These eight functions and five values can be grouped into the following four general categories:• Biological Functions;• Hydrological Functions;• Water Quality Functions; and• Societal Values.The degree to which a wetland provides each of these functions or values is determined by one or more of thefollowing factors: landscape position, substrate, hydrology, vegetation, history of disturbance, and size. Eachwetland may provide one or more of the listed functions or values at a significant level. Criteria used toevaluate the level at which a wetland provided each specific wetland function and value is found in the HighwayMethodology Workbook Supplement.The factors determining the level of function provided by a wetland can often be broken into two categories: theeffectiveness and the opportunity. The effectiveness of a wetland to provide a specified function is generallydependent on factors within the wetland, whereas the opportunity to provide a function is often influenced bythe wetland’s position in the landscape and adjacent land uses. A principal function or value is an importantphysical component of a wetland ecosystem, and/or considered of special value or significance to society, froma local, regional, and/or national perspective.The RIDEM Rules 217 Rule 10.02 recognizes that freshwater wetlands support wildlife and provide wildlifehabitat; support public recreation and aesthetic values; provide flood protection; protect surface water andgroundwater supplies; and protect water quality. These functions, and the criteria used to evaluate the level ofeach function a wetland provides, are similar to those described by the “Descriptive Approach”.4.9.2 Affected EnvironmentThe hydrologic setting influences some of the functions and values provided by wetlands. The Study Areaoccupies part of a broad outwash deposit known as the Warwick Plains Delta (Delta). The Delta is composedmostly of well-sorted sands and gravels deposited by melt waters during the last retreat of the North Americancontinental glacier from Rhode Island. During this deglaciation, Narragansett Bay and adjacent parts of RhodeIsland, including the Airport, were submerged beneath a freshwater lake, Glacial Lake Narragansett. The Deltawas formed as a submerged feature within this lake and was exposed after the deposits impounding the lakebreached, causing it to drain. Subsequent sea level rise again submerged the portion of the Delta south of theAirport site, forming Greenwich Bay.The Airport passenger terminal and runways were built on a high part of the Delta that forms a drainage divide.Drainage flows east and south of the Airport to the Providence River (Narragansett Bay) and Greenwich Bay.Drainage from much of the Study Area north and west of the Airport flows to the Pawtuxet River, which discharges216 Highway Methodology Workbook Supplement. NAEEP-360-1-30a. U.S. Army Corps of Engineers New England District. September 1999.217 Regulations Governing the Administration and Enforcement of the Freshwater Wetlands Act (RIDEM, 2010)Chapter 4 – Affected Environment 4-52 July 2011\\mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH04_Affected_Env_JUL_2011.doc