FINAL SUPPLEMENTAL ENVIRONMENTAL ASSESSMENT Plantation Key Colony / North Plantation Key Proposed Wastewater Treatment System Village of Islamorada Monroe County, Florida Prepared For Federal Emergency Management Agency Region IV 3003 Chamblee-Tucker Rd. Atlanta, GA 30341 Prepared By URS Group, Inc. 200 Orchard Ridge Drive, Suite 101 Gaithersburg, MD 20878 700 South Royal Poinciana Blvd. Suite 1000 Miami Springs, FL 33166 October 20, 2003 TABLE OF CONTENTS ABSTRACT .......................................................................................................................................................... Ab-1 SECTION 1 INTRODUCTION....................................................................................................................... 1-1 1.1 PROJECT AUTHORITY ................................................................................................................................... 1-1 1.2 RELATED ENVIRONMENTAL DOCUMENTS.................................................................................................... 1-1 1.3 PROJECT LOCATION ..................................................................................................................................... 1-1 1.4 PURPOSE AND NEED..................................................................................................................................... 1-3 SECTION 2 ALTERNATIVES ANALYSIS.................................................................................................. 2-1 2.1 ALTERNATIVE 1 – NO ACTION ALTERNATIVE.............................................................................................. 2-1 2.2 ALTERNATIVE 2 – CENTRALIZED WASTEWATER TREATMENT PLANT ON BAYSIDE SITE)............................ 2-1 2.2.1 Wastewater Collection and Transmission System ........................................................................ 2-2 2.2.1.1 Collection System.................................................................................................................. 2-2 2.2.1.2 Transmission System Components ........................................................................................ 2-3 2.2.2 Wastewater Treatment Plant ......................................................................................................... 2-5 2.2.2.1 Site Description...................................................................................................................... 2-5 2.2.2.2 System Components .............................................................................................................. 2-6 2.2.2.3 System Operation................................................................................................................... 2-7 2.2.2.4 Effluent Disposal ................................................................................................................... 2-8 2.2.3 Construction Activities ................................................................................................................. 2-9 2.2.4 Operation and Maintenance ........................................................................................................ 2-10 2.3 ALTE3.2 Water Resources and WaterRNATIVE 3 – CENTRALIZED WASTEWATER TREATMENT PLANT ON OCEANSIDE............................... 2-10 2.3.1 Site Description........................................................................................................................... 2-10 2.4 ALTERNATIVES CONSIDERED BUT ELIMINATED FROM FURTHER CONSIDERATION .................................... 2-12 SECTION 3 AFFECTED ENVIRONMENT AND ENVIRONMENT CONSEQUENCES ...................... 3-1 3.1 TOPOGRAPHY, SOILS, AND GEOLOGY .......................................................................................................... 3-1 3.1.1 Topography................................................................................................................................... 3-1 3.1.2 Soils .............................................................................................................................................. 3-1 3.1.3 Geology......................................................................................................................................... 3-3 3.2 WATER RESOURCES AND WATER QUALITY ................................................................................................. 3-4 3.2.1 Groundwater ................................................................................................................................. 3-4 3.2.2 Inland, Nearshore, and Offshore Waters....................................................................................... 3-5 3.2.2.1 Inland Waters......................................................................................................................... 3-5 3.2.2.2 Nearshore and Offshore Marine Waters ................................................................................ 3-5 3.2.2.3 Stormwater............................................................................................................................. 3-6 3.2.3 Floodplains and Wetlands............................................................................................................. 3-8 3.2.3.1 Floodplains ............................................................................................................................ 3-8 3.2.3.2 Wetlands ................................................................................................................................ 3-9 3.3 BIOLOGICAL RESOURCES ........................................................................................................................... 3-10 3.3.1 Terrestrial Ecosystems ................................................................................................................ 3-13 3.3.1.1 Pine Rocklands and Tropical Hardwood Hammocks .......................................................... 3-14 3.3.1.2 Mangrove Forests and Salt Marshes .................................................................................... 3-15 3.3.1.3 Freshwater Systems ............................................................................................................. 3-16 3.3.1.4 Dunes and Coastal Ridges ................................................................................................... 3-16 3.3.2 Aquatic Ecosystems .................................................................................................................... 3-16 3.3.2.1 Seagrass Beds and Sand Flats .............................................................................................. 3-17 3.3.2.2 Coral Reefs .......................................................................................................................... 3-18 3.3.2.3 Hardbottom.......................................................................................................................... 3-18 3.3.2.4 Sandy Bottom ...................................................................................................................... 3-18 3.3.2.5 Alternative 1 - No Action Alternative.................................................................................. 3-18 3.3.2.6 Alternative 2 - Centralized Wastewater Treatment Plant on Bayside Site........................... 3-19 3.3.2.7 Alternative 3 - Centralized Wastewater Treatment Plant on Oceanside .............................. 3-19 3.3.3 Special Status Species................................................................................................................. 3-20 P:\GAITHERSBURG\89-FR954414.00\SEAS\SEA -- ISLAMORADA\PLANTATION FSEA FINAL DRAFT 10-21-03.DOC i TABLE OF CONTENTS 3.4 AIR QUALITY ............................................................................................................................................. 3-21 3.5 CULTURAL RESOURCES.............................................................................................................................. 3-22 3.6 SOCIOECONOMIC RESOURCES .................................................................................................................... 3-24 3.6.1 Tourism....................................................................................................................................... 3-24 3.6.2 Fishing Industry .......................................................................................................................... 3-26 3.6.3 Local Fees and Taxes.................................................................................................................. 3-27 3.6.4 Public Health............................................................................................................................... 3-29 3.7 DEMOGRAPHICS AND ENVIRONMENTAL JUSTICE ....................................................................................... 3-29 3.7.1 Population and Race.................................................................................................................... 3-30 3.7.2 Income and Poverty .................................................................................................................... 3-30 3.7.3 Wastewater Fees and Affordability for Keys Low-income Residents ........................................ 3-31 3.8 WASTES AND HAZARDOUS MATERIALS ..................................................................................................... 3-33 3.9 INFRASTRUCTURE .....................................................................................................................................