Forge River Watershed Sewer Project Environmental Assessment Town of Brookhaven, Suffolk County, New York FEMA-DR-4085-NY October 2018 U.S. Department of Homeland Security Federal Emergency Management Agency, Region II 26 Federal Plaza New York, NY 10278 Environmental Assessment Forge River Watershed Sewer Project, Town of Brookhaven, NY TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................... 1 1.1 SUFFOLK COUNTY COASTAL RESILIENCY INITIATIVE ...................................................................................................... 1 1.2 FORGE RIVER WATERSHED SEWER PROJECT ENVIRONMENTAL REVIEW PROCESS .............................................................. 1 2.0 PURPOSE AND NEED ....................................................................................................... 2 3.0 PROJECT BACKGROUND ............................................................................................... 2 4.0 ALTERNATIVES................................................................................................................ 4 4.1 ALTERNATIVE 1: NO ACTION .................................................................................................................................. 4 4.2 ALTERNATIVE 2: PROPOSED ACTION: MASTIC-SHIRLEY SEWER DISTRICT ESTABLISHMENT .................................................. 4 4.2.1 Combination of Gravity and Low-Pressure Sewers Collection System ................................................... 4 4.2.2 Exclusively Low-Pressure Sewers Collection System .............................................................................. 6 4.2.3 Advanced Wastewater Treatment Facility............................................................................................. 6 4.2.4 Implementation and Construction ......................................................................................................... 6 4.3 ALTERNATIVE 3: ON-SITE TREATMENT AND DISPOSAL—REPLACING EXISTING ON-SITE WASTEWATER TREATMENT AND DISPOSAL SYSTEMS WITH INNOVATIVE/ALTERNATIVE ON-SITE WASTEWATER TREATMENT AND DISPOSAL SYSTEMS (I/A OWTS ALTERNATIVE) ............................................................................................................................................................... 7 4.3.1 Treatment Methods ............................................................................................................................... 7 4.3.2 Implementation and Construction ......................................................................................................... 7 4.4 ALTERNATIVES CONSIDERED BUT DISMISSED .............................................................................................................. 8 4.4.1 Centralized System with Different Wastewater Treatment Technology ................................................ 8 4.4.2 Centralized System with Different Collection System Infrastructure ..................................................... 8 4.4.3 Centralized System with Alternative Location(s) for the AWTF ............................................................. 8 4.5 SUMMARY EVALUATION OF ALTERNATIVES ................................................................................................................ 9 5.0 AFFECTED ENVIRONMENT AND POTENTIAL IMPACTS ........................................ 9 5.1 RESOURCE TOPICS DISMISSED FROM DETAILED ANALYSIS ........................................................................................... 10 5.2 TOPOGRAPHY AND SOILS ..................................................................................................................................... 10 5.2.1 Existing Conditions ............................................................................................................................... 10 5.2.2 Potential Impacts and Proposed Mitigation ........................................................................................ 11 5.3 AIR QUALITY AND GREENHOUSE GASES .................................................................................................................. 12 5.3.1 Existing Conditions ............................................................................................................................... 12 5.3.2 Potential Impacts and Proposed Mitigation ........................................................................................ 13 5.4 WATER QUALITY ................................................................................................................................................ 16 5.4.1 Existing Conditions ............................................................................................................................... 16 5.4.2 Potential Impacts and Proposed Mitigation ........................................................................................ 19 5.5 WETLANDS AND COASTAL RESOURCES ................................................................................................................... 21 5.5.1 Existing Conditions ............................................................................................................................... 21 5.5.2 Potential Impacts and Proposed Mitigation ........................................................................................ 23 5.6 FLOODPLAINS, STORMS, AND SEA LEVEL RISE .......................................................................................................... 25 5.6.1 Existing Conditions ............................................................................................................................... 25 5.6.2 Potential Impacts and Proposed Mitigation ........................................................................................ 26 5.7 VEGETATION ..................................................................................................................................................... 28 5.7.1 Existing Conditions ............................................................................................................................... 28 5.7.2 Potential Impacts and Proposed Mitigation ........................................................................................ 29 i Environmental Assessment Forge River Watershed Sewer Project, Town of Brookhaven, NY 5.8 WILDLIFE AND FISH ............................................................................................................................................. 31 5.8.1 Existing Conditions ............................................................................................................................... 31 5.8.2 Potential Impacts and Proposed Mitigation ........................................................................................ 33 5.9 THREATENED AND ENDANGERED SPECIES AND CRITICAL HABITATS ............................................................................... 36 5.9.1 Existing Conditions ............................................................................................................................... 36 5.9.2 Potential Impacts and Proposed Mitigation ........................................................................................ 39 5.10 CULTURAL RESOURCES ........................................................................................................................................ 41 5.10.1 Existing Conditions ............................................................................................................................... 41 5.10.2 Potential Impacts and Proposed Mitigation ........................................................................................ 44 5.11 AESTHETIC RESOURCES ........................................................................................................................................ 45 5.11.1 Existing Conditions ............................................................................................................................... 45 5.11.2 Potential Impacts and Proposed Mitigation ........................................................................................ 46 5.12 LAND USE AND PLANNING ................................................................................................................................... 47 5.12.1 Existing Conditions ............................................................................................................................... 47 5.12.2 Potential Impacts and Proposed Mitigation ........................................................................................ 49 5.13 ENVIRONMENTAL JUSTICE .................................................................................................................................... 51 5.13.1 Existing Conditions ............................................................................................................................... 51 5.13.2 Potential Impacts and Proposed Mitigation ........................................................................................ 54 5.14 NOISE .............................................................................................................................................................. 55 5.14.1 Existing Conditions ............................................................................................................................... 55 5.14.2 Potential Impacts and Proposed Mitigation .......................................................................................