DRAINAGE REPORT PERMIT SUBMITTAL (FO EVISION 1st STREET – BERTHA STREET ROADWAY IMPROVEMENTS PROJECT Prepared For: Monroe County Department of Engineering 1100 Simonton Street, Room 2-216 Key West, FL 33040 November 2019 Prepared By: EAC Consulting, Inc. 5959 Blue Lagoon Drive, Suite 410 Miami, FL 33126 Darren Dyer, P.E. CA # 7011 FL License No. 73951 EAC No. 17078.HW01-00 TABLE OF CONTENTS Chapter 1 Project Overview ...................................................................................................................................... 3 1.1 Introduction ................................................................................................................................................. 3 1.2 Scope ............................................................................................................................................................ 3 1.3 Survey and Data Collection ......................................................................................................................... 3 Chapter 2 Location and Description of Project ........................................................................................................ 5 2.1 Project Location ........................................................................................................................................... 5 2.2 Project Description ...................................................................................................................................... 5 2.3 Project Typical Sections .......................................................................................................................... 5 Chapter 3 Environmental Permitting Criteria .......................................................................................................... 6 3.1 Environmental Permitting ........................................................................................................................... 6 3.2 Stormwater Quality Criteria ........................................................................................................................ 6 3.2.1 South Florida Water Management District (SFWMD)............................................................................ 6 3.3 Stormwater Quantity Criteria ..................................................................................................................... 7 3.4 Total Maximum Daily Load (TMDLs) and Nutrient Impaired Water Bodies ........................................... 7 3.5 FEMA Floodplain Impacts ......................................................................................................................... 7 3.6 Environmental Surroundings ...................................................................................................................... 8 3.7 Required Permits ....................................................................................................................................... 8 Chapter 4 Design Criteria and Parameters ............................................................................................................... 9 4.1 Stormwater Management Facilities .......................................................................................................... 9 4.1.1 Retention/Detention Ponds ................................................................................................................... 9 4.1.2 Conveyance Systems ............................................................................................................................... 9 4.2 Optional Pipe Materials ........................................................................................................................... 10 4.3 Sea Level Rise ........................................................................................................................................... 10 4.4 Roadway Base Protection ..................................................................................................................... 11 4.5 Project Datum ....................................................................................................................................... 11 Chapter 5 Existing Drainage .................................................................................................................................... 12 5.1 Existing Drainage Patterns .................................................................................................................... 12 5.1.1 Bertha Street Drainage System ............................................................................................................. 12 5.1.2 Flagler Avenue & First Street Drainage System ................................................................................... 12 5.1.3 First Street Drainage System ................................................................................................................ 12 5.2 Control Elevations ................................................................................................................................. 13 5.2.1 Seasonal High Groundwater Table (SHGWT) ....................................................................................... 13 5.2.2 Tailwater Elevations .............................................................................................................................. 13 Drainage Report 1st Street / Bertha Street Roadway Improvements 1 5.3 Geotechnical Characteristics ................................................................................................................. 13 5.3.1 Soils Information ................................................................................................................................... 13 5.3.2 Geotechnical Data ................................................................................................................................. 14 Chapter 6 Drainage Analysis Methodology ............................................................................................................ 15 6.1 System Delineation and Parameters .................................................................................................... 15 6.2 Drainage Modeling Overview ............................................................................................................... 15 6.2.1 Existing Stormwater Master Plan ICPR Model ..................................................................................... 15 6.2.2 First Street / Bertha Street ICPR Model ............................................................................................... 15 6.3 Drainage System Modeling ................................................................................................................... 15 6.4 Design Storms and Rainfall Depths ...................................................................................................... 16 6.5 Time of Concentration .......................................................................................................................... 16 6.6 Pre‐Development ICPR Model .............................................................................................................. 16 6.7 Post‐Development ICPR Model ............................................................................................................ 17 Chapter 7 Stormwater Management Systems Evaluation ..................................................................................... 18 7.1 Proposed Drainage Patterns ................................................................................................................. 18 7.1.1 System 1 – Bertha Street ...................................................................................................................... 18 7.1.2 System 2 – Flagler Avenue & First Street ............................................................................................. 18 7.1.3 System 3 – First Street .......................................................................................................................... 18 7.2 Stormwater Management Facilities Evaluation ................................................................................... 19 7.3 Conclusion ............................................................................................................................................. 19 Appendix A – Figures, Exhibits & Maps Appendix B – Pre‐Development Drainage Maps Appendix C – Post‐Development Drainage Maps Appendix D – Regulatory Calculations Appendix E – Site Facility Calculations Appendix F – Conveyance Calculations Appendix G – Pre‐Development ICPR Model Appendix H – Post‐Development ICPR Model Appendix I – Model Summary Tables Appendix J – Geotechnical, Environmental & SLR Reports Appendix K – Record Documents Drainage Report 1st Street / Bertha Street Roadway Improvements 2 Chapter 1 Project Overview 1.1 Introduction Monroe County Engineering and Public Works Department is proposing roadway and streetscape improvements for First Street and Bertha Street on the island of Key West. In conjunction with the proposed streetscape improvements, the County is proposing to replace and upgrade the existing drainage system. Currently, the surrounding lands consist of residential and commercial areas. The project is located in Monroe County Florida and is within the jurisdictional boundary of the South Florida Water Management District (SFWMD). The regulations of SFWMD will govern the minimum stormwater management