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 , 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 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 design criteria for the project; however, the proposed stormwater management system will also conform to any additional design requirements of the Florida Department of Environmental Protection (FDEP) and United States Army Corps of Engineers (USACE).

For continuity with the previous drainage evaluations performed for the island of Key West, the project limits have been differentiated into drainage systems based on the City’s 2012 Stormwater Master Plan, which utilized existing geographical, topographical and waterbody discharge divides, as well as based on adjacent existing and proposed projects within the island.

1.2 Scope This Drainage Report describes the existing drainage conditions and addresses the proposed drainage improvements for Bertha Street and First Street corridor from South Roosevelt Boulevard to North Roosevelt Boulevard. It has been prepared as part of the Environmental Resource Permit (ERP) package to be submitted to SFWMD for review and approval. Accordingly, proposed stormwater management facilities have been designed to conform to SFWMD water quality and water quantity criteria. The scope of this Drainage Report consists of addressing the permitting water quality and water quantity requirements as well as the establishment of a detailed hydrologic and hydraulic model to evaluate the existing and proposed drainage conditions (flood stages and discharges) within the limits of the project. The analysis demonstrates that the proposed improvements will have no negative drainage impacts to the surrounding areas and that the proposed stormwater management facilities will have the capacity to adequately treat and attenuate roadway runoff within the project limits.

1.3 Survey and Data Collection Field and record data collected for this project includes previously issued plans or permits, as‐built plans, field reviews, topographic survey, geotechnical testing, and aerial image observation. Topographic survey was provided by the project’s surveyor, Longitude, for the entire project limits, with supplemental topographical and subsurface utility information shown based on the best information available. In addition to topographic survey, geotechnical data, was provided by the project’s geotechnical consultant, PSI.

Drainage Report 1st Street / Bertha Street Roadway Improvements 3 The topographic survey was used to develop base maps and assist in establishing the pre‐ development hydrologic and hydraulic conditions. The City of Key West’s Stormwater Master Plan and Stormwater Infrastructure Maps, existing SFWMD permits, as‐built plans were obtained and used to establish existing drainage conditions, for the evaluation of offsite contributory drainage areas, for the drainage design and modeling, and permit application submittal.

Drainage Report 1st Street / Bertha Street Roadway Improvements 4 Chapter 2 Location and Description of Project

2.1 Project Location The project is located in Key West, Monroe County, Florida. The subject roads are 1st Street, from North Roosevelt Blvd (US 1) to Flagler Avenue and Bertha Street, from Flagler Avenue to South Roosevelt Blvd (A1A). The project site is located within Section 04 ‐ Township 68 South ‐ Range 25 East as well as Section 05 ‐Township 68 South ‐ Range 25 East.

2.2 Project Description Monroe County has plans to construct repairs and improvements to 1st Street and Bertha Street in the City of Key West, Florida. The approximately 0.8‐mile project improvements include milling and resurfacing, asphalt reconstruction, drainage system improvements and new signing and pavement markings which will enhance the operations of the corridor for motorists, bicyclists and pedestrians. The purpose of this report is to document the drainage analyses and design associated with the proposed improvements, as well as, document that the regulatory agency requirements for stormwater management are met.

2.3 Project Typical Sections Refer to Appendix A for the Project Typical Sections.

Drainage Report 1st Street / Bertha Street Roadway Improvements 5 Chapter 3 Environmental Permitting Criteria

3.1 Environmental Permitting This section outlines Federal, State and local stormwater quality criteria and environmental permitting requirements applicable to the proposed roadway improvements. The criteria and parameters outlined in this report are derived from the applicable regulations, permit design manuals and design standards. The project is under the jurisdiction of the South Florida Water Management District (SFWMD), which will require an Environmental Resource Permit (ERP) for the proposed roadway improvements. There is no existing permit for the First Street limits of the project, however, Bertha Street was permitted by the District in 1991 under Permit No. 44‐00416‐S. Accordingly, a modification of the existing permit is sought for the project.

3.2 Stormwater Quality Criteria Full water quality treatment of stormwater runoff is required for reconstruction areas within the roadway corridor.

3.2.1 South Florida Water Management District (SFWMD) The SFWMD has lead jurisdiction over the stormwater quality criteria for the project and generally requires that all projects meet state water quality standards, as set forth in Chapter 62‐40, Florida Administrative Code (FAC). According to the SFWMD Basis of Review for Environmental Resource Permit Applications (Permit Volume II), all projects must meet the following volumetric retention/detention requirements:  For wet detention systems, the first inch of runoff from the project or the total runoff from 2.5 inches times the percentage of imperviousness, whichever is greater, must be detained on site. A wet detention system maintains the bottom elevation lower than one foot above the seasonal high groundwater elevation and does not bleed‐down more than one‐half inch of detention volume in 24 hours;  The dry detention systems shall provide 75 percent of the required wet detention volume. Dry detention systems consist of those with bottom elevation at least one foot above the seasonal high groundwater elevation or control elevation for the area;  Retention systems can only provide 50 percent of the wet detention volume;  Projects with more than 50 percent of imperviousness, discharge to receiving water bodies must be made through baffles, skimmers, or other mechanism suitable for preventing oil and grease from discharging to or from the retention/detention areas

Drainage Report 1st Street / Bertha Street Roadway Improvements 6 3.3 Stormwater Quantity Criteria SFWMD requires that offsite discharge rates be limited to rates not causing adverse impacts to existing off‐site properties, and: 1. Historic discharge rates, 2. Rates determined in previous SFWMD permit action, or 3. Basin allowable discharge rates. Based on the proposed roadway improvements, there will be no significant net increase in impervious area, nor will there be a significant loss of above ground storage within the roadway; therefore, no significant increase in stormwater runoff is anticipated.

3.4 Total Maximum Daily Load (TMDLs) and Nutrient Impaired Water Bodies The Florida Department of Environmental Protection (FDEP) has developed a Basin Management Action Plan (BMAP) which implements certain measures in order to restore and protect state waters and addresses Total Maximum Daily Load (TMDLs) requirements for impaired waterbodies. TMDLs represent the maximum amount of a given pollutant that a waterbody can assimilate and still meet water quality standards, including its applicable water quality criteria and its designated uses. TMDLs are developed for waterbodies that are verified as not meeting their water quality standards. Section 303(d) of the Federal Clean Water Act requires states to submit to the United States Environmental Protection Agency (EPA) lists of surface waters that do not meet applicable water quality standards (impaired waters) and establish a TMDL for each pollutant causing the impairment of listed waters on a schedule. The FDEP has developed such lists, commonly referred to as 303(d) lists, since 1992. The list of impaired waters in each basin, referred to as the Verified List, is also required by the FWRA (Subsection 403.067[4], Florida Statutes [F.S.]); the state’s 303(d) list is amended annually to include basin updates. The proposed project is located within WBID 6014A, WBIDs 8073, 8073E, 8073H, and WBID 8079 and will ultimately contribute stormwater to coastal Key West and Outlying Islands, including Smathers Beach, Key West’s South Beach, and the Atlantic Ocean, which are currently impaired for Copper (6014A), for Nitrogen (8073 & 8079), and for Bacteria (8073E & 8073H). Refer to Appendix A for the Impaired Waters, TMDLs, and Map.

3.5 FEMA Floodplain Impacts The project’s floodplain information is obtained from numbers 12087C1516K and 12087C1517K of the Federal Emergency Management Agency’s (FEMA) Flood Insurance Rate Map (revised February 18, 2005). The project limits are located within Zone AE with Base Flood Elevations ranging from 7 feet to 10 feet NGVD 29 (5.65 feet to 8.65 feet NAVD 88). In accordance with Executive Order 11988m “Floodplain Management”, USDOT Order 5650.2, “Floodplain Management Protection”, and Federal‐Aid Policy Guide 23 CFR 650A, floodplains

Drainage Report 1st Street / Bertha Street Roadway Improvements 7 must be protected. The intent of these regulations is to avoid or minimize highway encroachments within the base floodplains, and to avoid supporting land use development incompatible with floodplain values. Given the project’s scope and proposed improvements, there is no change in flood “risk” or adverse floodplain impacts associated with this project, accordingly floodplain encroachment compensation is not required for this project due to the net zero effect on the floodplain. Refer to the FEMA Floodplain Map and FEMA Firmettes in Appendix A.

3.6 Environmental Surroundings Wetlands There are no existing wetlands located within the project limits. Contamination There are nine sites identified as existing and/or potential contamination sources within 250 feet of the project limits based on the project’s Assessment of Potential Contamination report, prepared by SWC and dated November 5, 2018. Refer to Appendix J for an excerpt from the report.

3.7 Required Permits The following is a guideline of the environmental permitting requirements anticipated for the project:  South Florida Water Management District (SFWMD) Individual Environmental Resource Permit(s), including modifications to the following permits: o SWM 44‐00416‐S  SFWMD Consumptive Use (Dewatering) Permit  Florida Department of Environmental Protection (FDEP) NPDES Permit  A United States Army Corps of Engineers (USACE) Section 404 Dredge & Fill Permit is not required, since there are no wetlands within the project limits.

Drainage Report 1st Street / Bertha Street Roadway Improvements 8 Chapter 4 Design Criteria and Parameters

Proposed drainage facilities have been designed in accordance with the following design criteria and parameters established by Monroe County, SFWMD and FDOT: 1. Florida Department of Transportation (FDOT) FDM 2. Florida Department of Transportation (FDOT) Standard Plans 3. Florida Department of Transportation (FDOT) Drainage Manual 4. SFWMD Environmental Resource Permit Applicant’s Handbook Volumes I and II The following subsections describe the design criteria for the available best management practices (BMP's) governing the project’s drainage design.

4.1 Stormwater Management Facilities

4.1.1 Retention/Detention Ponds Size Requirements:  No minimum area requirement for dry ponds. The bottom elevation of dry ponds must be set at least one foot above the control elevation. Freeboard:  Per FDOT, as a safety factor for hydrologic inaccuracies, grading irregularities, control structure clogging, and downstream stage uncertainties, at least 1‐ft of freeboard is required above the maximum stage of the pond. The freeboard is the vertical distance between the maximum design stage elevation of the pond and the inside edge of the berm. For linear treatment swales, the minimum freeboard is 0.50‐ft. Discharge Structures:  Per SFWMD, control structure(s) shall include a baffle system to encourage discharge from the center of the water column rather than the top or bottom. Baffle design shall be per FDOT Standard Plans 425‐070.  Per SFWMD, control structures shall be designed so that the gravity control devices are sized based upon a maximum design discharge of ½ inch of the retention volume in 24 hours. The devices shall incorporate dimensions no smaller than six square inches, three inches minimum dimension, and/or 20 degrees for “V” notches.

4.1.2 Conveyance Systems Conveyance systems collect and carry stormwater runoff to receiving bodies of water, other conveyance systems, detention ponds, retention ponds, and French drains. The two main conveyance systems used in roadway projects are storm sewer systems and roadway and median ditches or swales. The design of both storm sewer systems and

Drainage Report 1st Street / Bertha Street Roadway Improvements 9 conveyance ditches/swales shall be based on FDOT drainage design criteria. The criteria are summarized as follows:  For General design, a 3‐year recurrence interval shall be used in the design of storm sewer systems.  Design of storm sewer systems shall maintain hydraulic grade line (HGL) a minimum of one foot below gutter line when minor losses are not computed in the design. When minor losses are considered, HGL may be maintained at the gutter line.  Design of storm sewer system shall maintain minimum and maximum velocities of 2.5 and 15 feet per second, respectively.  Roadway and median ditches shall be designed to convey the 10‐year frequency storm. Outfall ditches shall be designed to convey the 25‐year frequency storm.  The minimum freeboard for linear dry detention ponds (swales) is 0.5 ft.  The maximum allowed velocity in grassed ditches shall be 5.5 feet per second. For velocities higher than 5.5 feet per second, linings other than grass shall be used such as paved concrete, flexible, riprap, geo‐grid or interlocking concrete blocks.  Two feet sumps shall be provided at all drainage structures when downstream pipe is relatively flat or when the structure has more than one pipe connection (to/from), to minimize entrance of sediments into drainage pipes.  The minimum pipe size and design service life are 18 inches and 100 years, respectively.

4.2 Optional Pipe Materials FDOT’s Culvert Service Life Estimator was utilized in the determination of optional pipe materials for the project. Existing soil properties were based on geotechnical corrosion test results included in the geotechnical data provided by the project’s geotechnical consultant. Refer to Appendix E for the results of the Optional Pipe Material Analysis and Appendix J for the Geotechnical Report.

4.3 Sea Level Rise The County has determined that the improvements for this project should include roadway reconstruction based on sea level rise (SLR) criteria. A sea level rise analysis was performed by GIT Consulting, refer to Appendix J for the report documenting the proposed recommendations. Based on the referenced SLR study (Table 2), the minimum edge of pavement (EOP) elevation for the project was recommended to be elevation 2.30 (ft‐NAVD), in order to achieve a 2% flood exceedance on an annual basis for the year 2060. For the year 2040, the minimum edge of pavement elevation for the project corridor should be set at 1.30 (ft‐NAVD), in order to achieve a 2% flood exceedance on an annual basis. The County has directed that a minimum edge of pavement elevation should be set at 1.30 (ft‐ NAVD) in order to maintain the county’s interim criteria of 2% annual flood exceedance through the design year, 2040.

Drainage Report 1st Street / Bertha Street Roadway Improvements 10 4.4 Roadway Base Protection FDOT has established the following criteria for base protection of roads:  Freeways and Rural Multilane Mainline facilities shall provide a 3‐ft clearance for the roadway base course above the base clearance water elevation (i.e. SHGWT).  Ramps shall provide a 2‐ft clearance for the roadway base course above the base clearance water elevation (SHGWT).  All other facilities shall provide a 1‐ft clearance for the roadway base course above the base clearance water elevation (SHGWT). Using a base clearance water elevation (SHGWT) of 0.00 ft NAVD, the minimum roadway base elevation allowable for all other facilities is 1.00 ft NAVD. The applicable criterion for First Street and Bertha Street is 1‐ft clearance for an FDOT owned roadway. However, First Street and Bertha Street are not owned by the Department and are owned by Monroe County. Since achieving 1 foot of base clearance for First Street and Bertha street is not feasible, alternative methods for stabilizing the roadway base layer will be employed, such as geogrid or equivalent products.

4.5 Project Datum All elevations in this report, calculations and drainage plans are in reference to the North American Vertical Datum, NAVD 1988 (NAVD 88). However, some existing permits, record drawings/as‐builts, and other referenced documents provide elevations in reference to the National Geodetic Vertical Datum of 1929 (NGVD 29). Accordingly, a datum conversion has been provided in order to convert elevations between the two datums. The datum shift was determined using the NGS Vertcon2 conversion tool and was provided within the City of Key West’s Stormwater Master Plan (SWMP), 2012. The datum shift used to convert NAVD 88 to NGVD 29 within the study is summarized in Table 4.5 below. Refer to Appendix A for the referenced excerpt from the SWMP.

Table 4.5 – Datum Conversion from NAVD 88 to NAVD 29

Location Latitude Longitude Conversion (ft.) 1st Street/Bertha Street 24° 33’ 26” N 81° 47’ 14’ ‐1.345

Drainage Report 1st Street / Bertha Street Roadway Improvements 11 Chapter 5 Existing Drainage

The First Street / Bertha Street project corridor contains 3 distinct drainage systems, one on Bertha Street, from S. Roosevelt Boulevard (A1A) to Flagler Avenue, one consisting of the Flagler Avenue Drainage System, and one on First Street from north of Flagler Avenue to N. Roosevelt Boulevard (US1).

5.1 Existing Drainage Patterns

5.1.1 Bertha Street Drainage System System 1 consists of a series of isolated ditch bottom inlets that collect runoff on both sides of the street and convey to a series of wells located on the south side the roadway. Eleven (11) individual systems exist on Bertha St. between S. Roosevelt Blvd. and Flagler Ave., each consisting of two (2) inlets, a detention box, and a drainage well. The existing drainage system(s) were permitted in 1991 by SFWMD under SWM 44‐00146‐S, providing full on‐site retention for the 5‐year, 20‐minute design storm. A minor modification was approved in 1994 by the District for the addition of concrete sidewalks and a bicycle path. It has been noted that Bertha Street experiences flooding and standing water issues. Based on the relatively high groundwater condition, discharge capacity through the existing wells is limited. Also, since the drainage systems have no overflow via an outfall, any stormwater runoff in excess of the capacity of the existing wells, remains as standing water within the Bertha Street right of way, and drains down the side streets, Atlantic Blvd., Blanche St., and Venetia St. Based on the City of Key West’s Stormwater Master Plan, the portion of Bertha Street, northwest of Atlantic Blvd. is included as a part of drainage basin B110. Refer to Appendix K for excerpts from the Stormwater Master Plan, as well as a map of the City’s stormwater infrastructure.

5.1.2 Flagler Avenue & First Street Drainage System System 2 consists of two (2) ditch bottom inlets located at the curb returns just west of the intersection of First Street and Flagler Avenue. The inlets are connected to a manhole in the intersection. The manhole is part of a drainage trunkline pipe running from southwest to northeast along Flagler Ave., which provides conveyance for stormwater runoff collected along Flagler towards the Salt Ponds adjacent to Key West International Airport, to the north of the project corridor. Refer to Appendix K for excerpts from the Stormwater Master Plan, as well as a map of the City’s stormwater infrastructure.

5.1.3 First Street Drainage System System 3 consists of a closed drainage system consisting of curb and ditch bottom inlets providing stormwater collection and conveyance for First Street and portions of the side streets that intersect First. In addition to collecting runoff from the side streets, based on analysis that was prepared for the City of Key West’s Stormwater Master Plan, a

Drainage Report 1st Street / Bertha Street Roadway Improvements 12 significant portion of the neighborhood, south of First Street also drains to and is collected and conveyed by the First Street drainage system. The system outfalls to the ocean at Garrison Bight via a 36” outfall. In 2009, a triple chamber baffle box was installed on the existing First Street outfall pipe as a part of the Water Quality Improvement Program (FKWQIP), where a number of existing outfalls on Key West were retrofitted with the devices in order to improve the quality of the stormwater being discharged to offsite waterbodies. Refer to Appendix K for excerpts from the Stormwater Master Plan, as well as a map of the City’s stormwater infrastructure, and plans related to the existing water quality treatment baffle box.

5.2 Control Elevations

5.2.1 Seasonal High Groundwater Table (SHGWT) The SHGWT for the drainage systems within the project limits was determined based on information provided in the City of Key West’s Master Plan, and the SLR study provided by GIT Consulting. Refer to Appendix K for excerpts from the Stormwater Master Plan. The SHGWT is expected to be the same as Sea Level. Accordingly, to account for 6 inches of Sea Level Rise over the next 20 years, two SHGWT elevations were utilized:  Current year: SHGWT = 0.00’ NAVD  Year 2040: SHGWT = 0.50’ NAVD

5.2.2 Tailwater Elevations Similar to SHGWT, tailwater elevations were determined based on information provided in the City of Key West’s Master Plan, and the SLR study provided by GIT Consulting. Refer to Appendix K for excerpts from the Stormwater Master Plan. The tailwater for all drainage systems within the project limits is the waters of the Atlantic Ocean/ surrounding the island of Key West, so the tailwater elevation is sea level. Accordingly, to account for 6 inches of Sea Level Rise over the next 20 years, two SHGWT elevations were utilized:  Current year: SHGWT = 0.00’ NAVD  Year 2040: SHGWT = 0.50’ NAVD

5.3 Geotechnical Characteristics

5.3.1 Soils Information Review of the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soils Map, the entire project area is underlain by Urban Land (0 to 2% slopes). See Appendix A for the Soils Map.

Drainage Report 1st Street / Bertha Street Roadway Improvements 13

5.3.2 Geotechnical Data Geotechnical data is included in the Geotechnical Report by PSI, Inc. See Appendix J for a copy of the Geotechnical Report.

Drainage Report 1st Street / Bertha Street Roadway Improvements 14 Chapter 6 Drainage Analysis Methodology

6.1 System Delineation and Parameters In order to accurately define and simulate the drainage basins and systems within the project limits, the City of Key West’s Stormwater Master Plan (SWMP) – 2012 update was referenced. As a part of that effort, the City collected existing stormwater drainage reports, as‐built/record drawings, LIDAR, and other data. Accordingly, the Stormwater Master Plan provides a complete review and analysis of stormwater infrastructure within the island and serves as a well‐detailed guide for establishing existing drainage conditions within the project corridor and determining offsite contributing areas. The project corridor was subsequently subdivided based on existing collection and conveyance systems, while being cognizant of the offsite drainage areas that contribute stormwater runoff to the First Street and Bertha Street drainage systems, previously established by the SWMP. Please refer to Appendices B & C for pre & post‐development drainage maps, Appendix D for land use tables, and to Appendix K for excerpts from the City of Key West’s Stormwater Master Plan.

6.2 Drainage Modeling Overview The Interconnected Pond Routing (ICPR4) computer model was used to evaluate the proposed drainage systems for several design storm conditions.

6.2.1 Existing Stormwater Master Plan ICPR Model As a part of the City of Key West’s Stormwater Master Plan update, a drainage model was created in order to simulate conditions on the island. For that effort, an ICPR V3 model was utilized by the City at the time. As a part of the First Street / Bertha Street project, a copy of this existing model was obtained and updated in order to accurately simulate the existing and proposed conditions, based on an existing, vetted, and approved drainage model.

6.2.2 First Street / Bertha Street ICPR Model Utilizing and modifying the City of Key West’s Stormwater Master Plan ICPR model, a project‐specific drainage model was created in order to simulate conditions within the project corridor. Since the ICPR V3 software is no longer being supported by its developer, the existing model was upgraded to the current version, ICPR V4.

6.3 Drainage System Modeling Using ICPR4, Stormwater runoff hydrographs have been generated by the Soil Conservation Service (SCS) hydrograph method for the size of the drainage basins, land use, soil condition and regional location of this project.

Drainage Report 1st Street / Bertha Street Roadway Improvements 15 The drainage basin areas were estimated using the Bentley Microstation computer aided design and drafting (CADD) package. The runoff Curve Numbers (CN) for the on‐site basins were estimated to be 98, based on guidance within the FDOT Drainage Manual for curb‐and‐gutter roadway sections, comprised of impervious surface. Runoff CN values for offsite basins were based on the existing SWMP CN values. Refer to Land Use Tables in Appendix D.

6.4 Design Storms and Rainfall Depths To verify that the Stormwater quantity criteria are met, the 5‐year, 24‐hour, 10‐year, 24‐hour, 25‐ year, 72‐hour, and 100‐year, 72‐hour design storm events were simulated in ICPR, consistent with the City’s Stormwater Master Plan: Table 6.4 – Design Storm Events & Rainfall Depths Design Storm Event Rainfall Depth (inches) FLmod 5‐year, 24‐hour 6.0 FLmod 10‐year, 24‐hour 7.0 SFWMD 25‐year, 72‐hour 12.0 SFWMD 100‐year, 72‐hour 17.0

The Flmod modified distribution was used for the 24‐hour storm event routing. The SFWMD distribution was used for 72‐hour storm event routing, as outlined in the SFWMD Permit Manual.

6.5 Time of Concentration The pre‐ and post‐development condition onsite drainage basins within the site are relatively small and highly impervious. These basins are presumed to have a TOC less than 10 minutes. Therefore, a 10‐minute TOC was assumed for all basins where the majority of runoff occurs via overland flow, consistent with the FDOT Drainage Manual. For offsite drainage basins served by relatively long storm drainage systems (conduits and/or channels), the TOC was estimated based on the City of Key West’s Stormwater Master Plan.

6.6 Pre‐Development ICPR Model For the pre‐development conditions, the City’s Stormwater Master plan ICPR model was updated to include Bertha Street. An overland weir simulating the Bertha Street roadway cross section was included in the model, in order to simulate how stormwater would overflow from Bertha Street into the adjacent areas. Existing drainage wells on Bertha Street were not included in the model, due to their low discharge capacity. Since the wells were originally designed for the 5‐ year, 20‐minute design storm, as any effect they had on flood stages for the design storm events modeled would be negligible, consistent with observations of Bertha Street flooding. Please refer to Appendix G for pre‐development model input & results.

Drainage Report 1st Street / Bertha Street Roadway Improvements 16 6.7 Post‐Development ICPR Model For post‐development conditions, the City of Key West’s Stormwater Master Plan ICPR model was updated to simulate a new trunkline servicing Bertha Street was simulated as discharging to the future Dennis Street Pump Station. Similarly, the existing trunkline on First Street & modified system was simulated in order to represent the post‐development conditions, as well as the new inlets proposed within the roadway. For both streets, there was no change in land use or impervious area, nor any negligible change in the above ground storage volume. Water quality treatment will be provided for both streets prior to offsite discharge via existing and proposed water quality treatment devices, hydrodynamic separators, or approved equivalent products. Please refer to Appendix H for pre‐development model input & results, and to Appendix I for a comparison of pre‐vs‐post development peak flood stages.

Drainage Report 1st Street / Bertha Street Roadway Improvements 17 Chapter 7 Stormwater Management Systems Evaluation

7.1 Proposed Drainage Patterns

7.1.1 System 1 – Bertha Street System 1 will collect stormwater runoff from the roadway in a similar fashion as its current design, however, with additional collection and conveyance capacity since a brand new drainage system is proposed. Along the roadway, more inlets are provided than in the existing condition, in order provide sufficient collection of stormwater runoff to satisfy spread criteria. Larger lateral drainage pipes for increased capacity, as well as a maximum 36‐inch diameter trunkline provide conveyance of stormwater runoff towards the Dennis Street Stormwater Pump Station at Venetia Street for discharge to the existing salt ponds adjacent to Key West International Airport and Key West High School. Full on‐site water quality treatment will be provided by means of a new water quality treatment device / hydrodynamic separator prior to discharge into the pump station. Existing shallow injection wells and associated detention boxes will be abandoned in place and removed, respectively.

7.1.2 System 2 – Flagler Avenue & First Street System 2 will continue to collect stormwater runoff along Flagler Avenue in the same way the existing system does; however, the two existing ditch bottom inlet structures in the roadway pavement will be replaced by two Type 5 curb inlets for stormwater collection. No additional inlets are required along First Street between System 2 and System 3 to satisfy spread criteria. Conveyance for this system to the existing Flagler Avenue trunkline will be maintained via existing pipes.

7.1.3 System 3 – First Street System 3 will collect stormwater runoff from the roadway in a similar fashion as its current design, however, with additional collection and conveyance capacity within the First Street right‐of‐way, where new curb inlets are proposed. Whereas in the existing condition, stormwater runoff from First Street would run down into the side streets and was collected by ditch bottom inlets located at the curb returns, the proposed drainage system for First Street will provide collection via curb inlets on First Street, which will connect to the existing trunkline providing conveyance for First Street. Since the existing First Street trunkline pipe was originally constructed in 1960, prior to installation of the new drainage system modifications, the pipe will be inspected for structural adequacy and restored/remediated as necessary, in order to provide continued service for First Street. A backflow prevention device / check valve will be installed on the existing trunkline, downstream of the existing manhole near Vivian Lane, in order to help mitigate King Tide flooding events. Existing side street connections will be maintained, in order to preserve existing drainage patterns. The proposed system will function similarly to the

Drainage Report 1st Street / Bertha Street Roadway Improvements 18 existing system and will utilize the existing trunkline north of Roosevelt Boulevard and stormwater discharges will continue to discharge into the Atlantic Ocean via the existing outfall at Garrison Bight. Full on‐site water quality treatment will be provided by means of the existing water quality treatment device / triple chamber baffle box prior to offsite discharge.

7.2 Stormwater Management Facilities Evaluation Based on the proposed drainage design evaluation for the proposed improvements, the stormwater management facilities will meet the County’s requirements.

7.3 Conclusion Based on the proposed drainage design evaluation for the proposed improvements, the stormwater management facilities required to meet FDOT drainage criteria, as well as SFWMD permit criteria, no negative drainage impacts are anticipated for the surrounding areas and the proposed stormwater management facilities will have the capacity to adequately treat and attenuate roadway runoff within the First Street and Bertha Street roadway rights‐of‐way, with no additional offsite right‐of‐way acquisition required solely for drainage purposes.

Drainage Report 1st Street / Bertha Street Roadway Improvements 19

APPENDIX A FIGURES, EXHIBITS & MAPS

MONROE COUNTY MIAMI-DADE COUNTY

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1 S T Legend )"C5A PROJECT LIMITS

B E R T H A S T

UVA1A

1,000 500 0 1,000 Feet MONROE COUNTY O Drawn By: EG 1ST STREET/ BERTHA STREET PROJECT LOCATION MAP FIGURE Checked by: DD

ROADWAY IMPROVEMENTS 1 Date: 6/14/19 MONROE COUNTY MIAMI-DADE COUNTY

¤£1 VD T BL AREA VEL OSE SHOWN N RO

1 S T Legend )"C5A PROJECT LIMITS EXISTINGOfficial ELU LAND USE ELU Commercial

Conservation

Educational

Industrial

B E Institutional R T H A Military S T Other Public - Utilities and Right-of-WaysROW UVA1A Public Buildings and Grounds

Recreational

Residential

Right-of-Ways

Utilities

Vacant or Undeveloped 1,000 500 0 1,000 Feet MONROE COUNTY O Drawn By: EG 1ST STREET/ BERTHA STREET EXISTING LAND USE MAP FIGURE Checked by: DD

ROADWAY IMPROVEMENTS 2 Date: 6/14/19 MONROE COUNTY MIAMI-DADE COUNTY 100

¤£1 VD T BL AREA VEL OSE SHOWN N RO

7

1 S T Legend )"C5A PROJECT LIMITS 15 7 SoilEXISTING Map LAND USE 7: Udorthents-Urban land complex 11

11: Urban land, 0% - 2% slopes

15: Cudjoe marl, tidal 99

18: Beaches 7

B and ROW E 99: Water R T H A 100: Waters of the Atlantic Ocean S T

UVA1A

18

100 1,000 500 0 1,000 Feet MONROE COUNTY O Drawn By: EG 1ST STREET/ BERTHA STREET SOILS MAP FIGURE Checked by: DD

ROADWAY IMPROVEMENTS 3 Date: 6/14/19 MONROE COUNTY MIAMI-DADE COUNTY

¤£1 VD T BL AREA VEL OSE SHOWN N RO

1 S T Legend )"C5A

PROJECT LIMITS

Political Jurisdictions

Flood Hazard Zones Zone Type

1%FLOOD Annual ZONE Chance Flood Hazard

B E Regulatory Floodway S R T H A S EXISTINGSpecial Floodway LAND USE T FLOOD ZONE A1A Area of Undetermined Flood Hazard UV

0.2% Annual Chance Flood Hazard

Future Conditions 1% Annual Chance Flood Hazard 1,000 500 0 1,000 and ROW Feet Area with Reduced Risk Due to Levee S

MONROE COUNTY O Drawn By: EG 1ST STREET/ BERTHA STREET FEMA FLOOD ZONE MAP FIGURE Checked by: DD

ROADWAY IMPROVEMENTS 4 Date: 6/14/19

National Flood Hazard Layer FIRMette Legend 24°33'45.03"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

W " Without Base Flood Elevation (BFE) 7

3 Zone A, V, A99 .

0 With BFE or Depth Zone AE, AO, AH, VE, AR 2 ' SPECIAL FLOOD 7

4 HAZARD AREAS Regulatory Floodway ° 1 8 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to OTHER AREAS OF Levee. See Notes. Zone X FLOOD HAZARD Area with Flood Risk due to Levee Zone D

NO SCREEN Area of Minimal Flood Hazard Zone X Effective LOMRs

OTHER AREAS Area of Undetermined Flood Hazard Zone D

GENERAL Channel, Culvert, or Storm Sewer STRUCTURES Levee, Dike, or Floodwall

20.2 B Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation

8 Coastal Transect Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary Coastal Transect Baseline OTHER Profile Baseline FEATURES Hydrographic Feature

Digital Data Available

No Digital Data Available MAP PANELS Unmapped Ü

The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location.

This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 7/11/2019 at 11:10:42 AM and does not reflect changes or amendments subsequent to this date and 8

1 time. The NFHL and effective information may change or ° 4

6 become superseded by new data over time. ' 4 2 .

9 This map image is void if the one or more of the following map 2

" elements do not appear: basemap imagery, flood zone labels, W

USGS The National Map: Orthoimagery. Data refreshed April, 2019. legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for Feet 1:6,000 24°33'12.30"N unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. National Flood Hazard Layer FIRMette Legend 24°33'34.06"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

W " Without Base Flood Elevation (BFE) 0

5 Zone A, V, A99 .

4 With BFE or Depth Zone AE, AO, AH, VE, AR 1 ' SPECIAL FLOOD 7

4 HAZARD AREAS Regulatory Floodway ° 1 8 0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to OTHER AREAS OF Levee. See Notes. Zone X FLOOD HAZARD Area with Flood Risk due to Levee Zone D

NO SCREEN Area of Minimal Flood Hazard Zone X Effective LOMRs

OTHER AREAS Area of Undetermined Flood Hazard Zone D

GENERAL Channel, Culvert, or Storm Sewer STRUCTURES Levee, Dike, or Floodwall

20.2 B Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation

8 Coastal Transect Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary Coastal Transect Baseline OTHER Profile Baseline FEATURES Hydrographic Feature

Digital Data Available

No Digital Data Available MAP PANELS Unmapped Ü

The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location.

This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 7/11/2019 at 11:07:25 AM and does not reflect changes or amendments subsequent to this date and 8

1 time. The NFHL and effective information may change or ° 4

6 become superseded by new data over time. ' 3 7 .

0 This map image is void if the one or more of the following map 5

" elements do not appear: basemap imagery, flood zone labels, W

USGS The National Map: Orthoimagery. Data refreshed April, 2019. legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for Feet 1:6,000 24°33'1.34"N unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. National Flood Hazard Layer FIRMette Legend 24°33'18.04"N SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT

W

" Without Base Flood Elevation (BFE)

0 Zone A, V, A99 6 .

0 With BFE or Depth Zone AE, AO, AH, VE, AR ' SPECIAL FLOOD 7 4

° HAZARD AREAS Regulatory Floodway 1 8

0.2% Annual Chance Flood Hazard, Areas of 1% annual chance flood with average depth less than one foot or with drainage areas of less than one square mile Zone X Future Conditions 1% Annual Chance Flood Hazard Zone X Area with Reduced Flood Risk due to OTHER AREAS OF Levee. See Notes. Zone X FLOOD HAZARD Area with Flood Risk due to Levee Zone D

NO SCREEN Area of Minimal Flood Hazard Zone X Effective LOMRs

OTHER AREAS Area of Undetermined Flood Hazard Zone D

GENERAL Channel, Culvert, or Storm Sewer STRUCTURES Levee, Dike, or Floodwall

20.2 B Cross Sections with 1% Annual Chance 17.5 Water Surface Elevation

8 Coastal Transect Base Flood Elevation Line (BFE) Limit of Study Jurisdiction Boundary Coastal Transect Baseline OTHER Profile Baseline FEATURES Hydrographic Feature

Digital Data Available

No Digital Data Available MAP PANELS Unmapped Ü

The pin displayed on the map is an approximate point selected by the user and does not represent an authoritative property location.

This map complies with FEMA's standards for the use of digital flood maps if it is not void as described below. The basemap shown complies with FEMA's basemap accuracy standards The flood hazard information is derived directly from the authoritative NFHL web services provided by FEMA. This map was exported on 7/11/2019 at 10:54:13 AM and does not reflect changes or amendments subsequent to this date and 8

1 time. The NFHL and effective information may change or ° 4

6 become superseded by new data over time. ' 2 3 .

1 This map image is void if the one or more of the following map 4

" elements do not appear: basemap imagery, flood zone labels, W

USGS The National Map: Orthoimagery. Data refreshed April, 2019. legend, scale bar, map creation date, community identifiers, FIRM panel number, and FIRM effective date. Map images for Feet 1:6,000 24°32'45.32"N unmapped and unmodernized areas cannot be used for 0 250 500 1,000 1,500 2,000 regulatory purposes. MONROE COUNTY MIAMI-DADE COUNTY

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1 S T Legend )"C5A

PROJECT LIMITS

B E S R T H A S EXISTING LAND USE T FLOOD ZONE UVA1A

FLOOD ZONE

and ROW S 1,000 500 0 1,000 Feet MONROE COUNTY O Drawn By: EG 1ST STREET/ BERTHA STREET USGS QUADRANGLE MAP FIGURE Checked by: DD

ROADWAY IMPROVEMENTS 5 Date: 6/14/19 MONROE COUNTY MIAMI-DADE COUNTY

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1 S T Legend )"C5A

PROJECT LIMITS

B E S R T H A S EXISTING LAND USE T FLOOD ZONE UVA1A

FLOOD ZONE

and ROW S 1,000 500 0 1,000 Feet MONROE COUNTY O Drawn By: EG 1ST STREET/ BERTHA STREET USGS TOPO MAP FIGURE Checked by: DD

ROADWAY IMPROVEMENTS 5 Date: 6/14/19

U.S. DEPARTMENT OF THE INTERIOR KEY WEST QUADRANGLE U.S. GEOLOGICAL SURVEY FLORIDA - MONROE COUNTY 7.5-MINUTE SERIES

-81.8750° -81.7500° 4 000m 24.6250° 12 E 13 14 15 16 17 18 19 20 21 22 23 24 24.6250° Bluefish Channel

23 2723000mN Calda Channel

22 22 Calda Bank

Jack Channel 21 21 Garrison Bight Channel

Northwest Channel

5 5

5 5 5 20 20

10 Pearl 5 5 Basin 10 5 NAS KEY WEST FLEMING 5 NAS KEY WEST KEY MAGAZINE DREDGERS KEY-SIGSBEE MAIN Fleming E RD Pearl 5

Bank Key 5 5 5 19

19 5 Dredgers Man of War 5 Key 5 Harbor 5

D R 5

Y

E R D D 5 K R 5  E 5 E n R G E ▄ O N 5 B M I S 5 IL M G G 5 5 E I Salt L 5 S F ^ 5 Pond 5 ^ 5 D Keys R E D G E R S K Frankfort E Y 18 R 5 D 18 Bank 5 5

5

5 5 5 £1 ¬«5 5 5 Middle ¤ 5

NAS 5 5 5 Ground Wisteria 10 5 5 10 KWTPA Island 5 5 5 5 5 5 5 NAVAL HOSPITAL 5 5

5 NORTHSIDE DR 5 5 5 KEY WEST 5 K Lakes Fleming E 5 N N Passage 5 5 Key Cut E D 5 Y ^ 5 D

5 R 5 5 17 5 NAS KEY WEST KEY WEST 5 5 17 5 & 5 NATIONAL PARK Ï PO H n 5 5 ▄ TRUMBO POINT ANNEX Trum bo ―│ 5 Key West 5 Point NAS 5 VE 1 FLAGLER AVE A 1 5 5 Bight PALM AVE N Garrison RSO E T F TTE AV H RIVIERA DR KWTA N ROOSEVELTPA BLVDRTY F Bight GA S 5 FO AVE T 5 10 RIS E MARGARET ST 5 AR AV Mule Key FRONT ST 5 5 H LES 5 5 £¤1 7 AP T ST n

5 H ▄ Ta n k I s l a n d WILLIAM ST 4TH ST 5 5TH ST S WHITEHEAD ST 5 ¬«5 T 5 CAROLINE ST 10 NAS KEY WEST VENETIAN DR ^F GEORGE ST1ST ST 5

EATON ST PEARY COURT n 5 ▄

5 FLEMING ST GEORGIA ST 10 Key West Cem !" VE 16 D ELIZABETH ST A U SOUTHARD ST R & V DUNCAN ST E 16 PO A OLIVIA ST  SEMINARY ST L  Key West International Airport n G 5 L Key ▄ n F LA BERTHA ST ▄ 5 ^ S F 5 WHITEHEADT ST TRUMAN AVE n West ▄

F 5 5 10 GRINNELL ST 5 ST 5 A ST EL  N 5 S ROOSEVELT BLVD G n O 5 N ▄ S A 10 VONPHISTERH STN ATLANTIC OCEAN JO 5 5 Smathers WASH INGTONWHITE ST ST 5 E T CATHERINE ST Beach 5 M H 5 M O D A M 5 V 5 AMELIA ST L 5 S A B 5 T S IC S NT T 5 LA 10 AT 5 5 10 5 5 5 5 Kingfish 5 15 10 5 15 Shoals 5

Whitehead Spit NAS KEY WEST TRUMAN ANNEX

14 14

Intracoastal Waterway

Main Ship 13 13 Channel

Hawk Channel

12 12

11 11

2710000mN 10

12 13 14 15 16 17 18 19 20 21 22 23 424000mE 24.5000° 24.5000° -81.8750° -81.7500°

× Produced by the United States Geological Survey FLORIDA ROAD CLASSIFICATION MN SCALE 1:24 000 North American Datum of 1983 (NAD83) Ø World Geodetic System of 1984 (WGS84). Projection and 1 0.5 0 KILOMETERS 1 2 Expressway Local Connector GN 1 000-meter grid:Universal Transverse Mercator, Zone 17R Secondary Hwy Local Road 5°28´ 1000 500 0 METERS 1000 2000 This map is not a legal document. Boundaries may be Ramp 4WD 97 MILS 10.50 1 generalized for this map scale. Private lands within government 0°20´ reservations may not be shown. Obtain permission before 6 MILS MILES WX Interstate Route /. US Route H State Route entering private lands. 1000 0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 QUADRANGLE LOCATION Imagery...... NAIP, November 2015 - February 2016 FEET Roads...... U.S. Census Bureau, 2016 UTM GRID AND 2017 MAGNETIC NORTH 1 Bay Keys Names...... GNIS, 1979 - 2018 DECLINATION AT CENTER OF SHEET Hydrography...... National Hydrography Dataset, 2002 - 2017 122 Snipe Keys CONTOUR INTERVAL 5 FEET USGSX24K23453 Contours...... National Elevation Dataset, 2011 3 U.S. National Grid NORTH AMERICAN VERTICAL DATUM OF 1988 Boundaries...... Multiple sources; see metadata file 2015 4 100,000 - m Square ID 34 Public Land Survey System...... BLM, 2017 This map was produced to conform with the 7643016360708 Wetlands...... FWS National Wetlands Inventory 2004 - 2009 MH National Geospatial Program US Topo Product Standard, 2011. A metadata file associated with this product is draft version 0.6.18 KEY WEST, FL ADJOINING QUADRANGLES Grid Zone Designation *7643016360708* NSN. NGA REF NO. 17R 2018 ENVIRONMENTAL RESOURCE PERMIT APPLICANT’S HANDBOOK VOLUME II Effective: MAY 22, 2016

A-13 ENVIRONMENTAL RESOURCE PERMIT APPLICANT’S HANDBOOK VOLUME II Effective: October 1, 2013

A-14 ENVIRONMENTAL RESOURCE PERMIT APPLICANT’S HANDBOOK VOLUME II Effective: October 1, 2013

A-18 ENVIRONMENTAL RESOURCE PERMIT APPLICANT’S HANDBOOK VOLUME II Effective: October 1, 2013

A-19 7/11/2019 Water Quality Assessments, TMDLs, and BMAPs Water Quality Assessments, TMDLs, and BMAPs

Florida Total Maximum Daily Load (TMDL)

TMDLs Adopted

TMDL Activities In Progress

Basin Management Action Plans (BMAPs)

Adopted BMAPs

Pending BMAPs

Waters Not Attaining Standards (WNAS)

This map displays the WBIDs that have been listed as Waters Not Attaining Standards, the TMDLS developed and the areas of the state that are currently involved in a BMAP. Data Layers available at http://geodata.dep.state.fl.us/

Esri, HERE, Garmin, USGS, NGA, EPA, USDA, NPS | FDEP, DEAR | FDEP | Florida Department of Environmental Protection (FDEP), DEAR | Florida DEP Watershed Assessment Section | environment, TMDL Total Maximum Daily Load Impairment, Environmental Monitoring and Modeling

https://fdep.maps.arcgis.com/home/webmap/print.html 1/1 6/13/2019 ArcGIS - Verified List Waterbody Ids (WBIDs) - Verified List WBIDs Verified List Waterbody Ids (WBIDs) - Verified List WBIDs

Verified List Waterbody Ids (WBIDs) - Verified List WBIDs

Coverage includes all the WBIDs (Waterbody IDs - RUN 54) that are currently included on the verified list for any 1mi parameter from Group 1, Cycle 1 through Group 5, Cycle 3, excluding WBID/parameter combinations that have subsequently been delisted in a later cycle. If a WBID is listed for multiple parameters the coverage contains overlapping polygons for each parameter. PLEASE NOTE: the verified list is not a list of all waters that do not meet water quality standards.

City of Key West, Esri, HERE, Garmin, INCREMENT P, USGS, METI/NASA, NGA, EPA, USDA | Florida DEP, Division of Environmental Assessment and Restoration (DEAR), Watershed Assessment Section

https://www.arcgis.com/home/webmap/print.html 1/1 Comprehensive Verified List includes updates from the Group 5 ‐ Cycle 3 Adoption (June 27, 2018)

OGC Water- 1998 303(d) Parameters Assessed Dissolved Concentration of Projected Year For Water- Priority for TMDL Verified Period Cycle Group Case Group Name Planning Unit County (-ies) WBID Water Segment Name body Parameters of Using the Impaired Oxygen/Biology Criterion or TMDL Comments7,8 body Type Development3 Assessment Data8 Number Class1 Concern Waters Rule (IWR) Pollutant of Concern Threshold Not Met Development3

1 5 09-0947 Florida Keys Lower Keys Monroe 6014A Key West Coastal 3M Copper > 3.7 µg/L Medium PP = No Data; VP = 9 / 31 < 21 days of beach 1 5 09-0951 Florida Keys Lower Keys Monroe 8073E South Beach (KW) Beach 3M Bacteria (Beach Advisories) High Beach advisories > 21 days/yr in 2002, 2003, 2004, 2005, and 2006. advisories < 21 days of beach 1 5 09-0954 Florida Keys Lower Keys Monroe 8073H Smathers Beach Beach 3M Bacteria (Beach Advisories) High Beach advisories > 21 days/yr in 2002, 2003, 2005, and 2006. advisories ENRG1 (AGM) 2016 (0.26 mg/L) ENRG1 2017 (0.32 mg/L) AGM ≤ 0.25 mg/L ENRG2 (AGM) ENRG2 2016 (0.34 mg/L) AGM ≤ 0.23 mg/L 2017 (0.26 mg/L) This waterbody is impaired for this parameter because the annual geometric Key West And Outlying ENRG3 ENRG3 (AGM) means exceeded the criterion more than once in a three year period during 3 5 18-0266 Florida Keys Lower Keys Monroe 8073 Coastal 3M Nutrients (Total Nitrogen) Medium Islands AGM ≤ 0.21 mg/L 2016 (0.25 mg/L) the verified period. This parameter is being added to the Verified List and the ENRG4 2017 (0.26 mg/L) department is requesting EPA add to the 303(d) List. AGM ≤ 0.21 mg/L ENRG4 (AGM) ENRG6 2016 (0.29 mg/L) AGM ≤ 0.17 mg/L 2017 (0.23 mg/L) ENRG6 (AGM) Insufficient Data ENRG3 (AGM) ENRG3 2016 (0.28 mg/L) This waterbody is impaired for this parameter because the annual geometric Atlantic Ocean (Monroe AGM ≤ 0.21 mg/L 2017 (0.25 mg/L) means exceeded the criterion more than once in a three year period during 3 5 18-0267 Florida Keys Lower Keys Monroe 8079 County; Cudjoe Key-Key Coastal 3M Nutrients (Total Nitrogen) Medium ENRG6 ENRG6 (AGM) the verified period. This parameter is being added to the Verified List and the West) AGM ≤ 0.17 mg/L 2016 (0.23 mg/L) department is requesting EPA add to the 303(d) List. 2017 (0.25 mg/L)

1 Florida's waterbody classifications are defined as: 1 - Potable water supplies 2 - Shellfish propagation or harvesting 3F - Recreation, propagation, and maintenance of a healthy, well-balanced population of fish and wildlife in fresh water 3M - Recreation, propagation, and maintenance of a healthy, well-balanced population of fish and wildlife in marine water 4 - Agricultural water supplies 5 - Navigation, utility, and industrial use 2 n is equal to the number of samples. When samples are collected at the same location less than 4 days apart, the median of those results represents a single sample for the purpose of determining n. 3 Where a parameter was identified as impaired under the IWR, a priority of “medium” was assigned. Exceptions are waters where the impairment poses a threat to potable water or human health, which have been assigned a “high” priority, and fecal coliform impairments, which have been assigned a “low” priority. All other listings are prioritized based on the following: it is our intent that listings with a "High" priority be addressed within the next 5 years, listings with a "Medium" priority be addressed within 5-10 years as resources allow, and listings with a "Low" priority be addressed within the next 10 years. 7 PP - Planning Period (10 year period; beginning and ending date vary by group/cycle combination); Where data are presented as x/y, x represents the number of exceedances and y represents the total number of samples. 8 VP - Verified Period (7.5 year period; beginning and ending date vary by group/cycle combination); Where data are presented as x/y, x represents the number of exceedances and y represents the total number of samples. A statewide TMDL for mercury, that will address this waterbody, is scheduled to be completed in 2012. N/A = Not Applicable, does not apply, or was not assessed in the previous cycle (i.e. it's a new WBID, waterbody type change, etc.). ^ Beach advisories are based on FL Dept of Health Enterococcus criterion of >103 CFU/100mL.

August 1, 2018 1 of 1 Florida Department of Envrironmental Protection Project Objective The objective of this evaluation was to determine the potential flooding issues on NSI using detailed computer simulation of stormwater runoff, storage, and flood routing. Storm surge from hurricanes is not included in this assessment.

Elevations and Reference Datum Elevations on a landscape are set relative to long-term elevations of the ocean and a network of fixed benchmarks. The U.S. National Geodetic Survey (NGS) maintains this network and has updated the historic standard established in 1929 with a new standard referred to as the 1988 datum. In practical terms, the landscape has not moved, but the yardstick used to measure the elevation has been shifted. The SFWMD and most municipalities has traditionally required the National Geodetic Vertical Datum of 1929 (NGVD29) for surveying and expressing elevations. However, the SFWMD and other municipalities are in the process of switching to the North American Vertical Datum of 1988 (NAVD88). This is clearly a time of transition so available literature is presented in one or the other reference datum. Except for the most recent aerial mapping by the state, elevations are typically expressed in NGVD29. The conversion between NAVD88 from NGVD29 in Key West is to subtract 1.345 feet (ft), so the NAVD88 elevation would be a smaller value for the same location. This conversion may vary slightly from one side of the City to the other, but this difference would be slight and of little consequence to normal public work facilities. The conversion was computed using the NGS VERTCON2 program at latitude 24° 33’ 26” N and longitude 81° 47’ 14” W (http://www.ngs.noaa.gov/cgi-bin/VERTCON/vert_con.prl). A main consequence of this datum conversion is a restatement of the sea level elevations surrounding Key West. The main National Oceanic and Atmospheric Administration (NOAA) tide gauge at Key West (ID: 8724580) is located in the boat basin on the west side of the main island. The updated tide levels are presented in Table 1 and are based on NOAA tide data from 1983 through 2001. From the updated NOAA data, one can see that while mean sea level used to be near -0.2 in the NGVD29 reference datum, it is now expressed close to -1.5 under the new NAVD88 datum. Similarly, stormwater evaluations are most often conducted under mean high water (MHW) conditions which used to be near elevation 1.1 NGVD29, but are now close to -0.2 NAVD88. For purposes of this study, the boundary condition at the ocean is being set at elevation 0 NAVD88, which is closer to the mean higher-high water (MHHW) which will represent a seasonally high high-tide level.

SEW/07112011-TM-FINAL.DOCX 6 NORTH STORMWATER DRAINAGE ASSESSMENT

TABLE 1 Tide Levels at the Key West NOAA Gauge in Different Vertical Datum North Stock Island Stormwater Assessment Elevation Elevation Description Acronym NAVD88 NGVD29

Mean Higher-High Water MHHW 0.05 1.40

Mean High Water MHW -0.24 1.11

Mean Tide Level MTL -0.88 0.47

Mean Sea Level MSL -1.52 -0.18

Mean Lower-Low Water MLLW -1.76 -0.42

Mean Range of Tide MN 1.28 1.28

Highest Water Level MAX 1.98 3.33

MAX DATE 9/8/1965

All elevations are in feet. Based on NOAA Gauge 8724580 for Key West, accessed 9/1/2009

Data Sources Data was collected from available sources from literature and the City. On August 18, 2010, a CH2M HILL engineer and OMI representative conducted a field review. The City- operated outfalls were inspected. During this inspection, the first culvert on the east (City Outfall 60) was found because it was not too far from the road and the mangroves had been partially trimmed. This 18-inch pipe was nearly blocked in front of the pipe, both ends; but evidence of flow was present because of trash gathered near the end located in the swale (inside the loop). There were extensive mangroves in front of both pipe ends. A similar situation was found at City Outfall 61 located just north of 60. Most of the remaining outfalls were not found as their ends were deep within the mangroves growing in the swales and along the coastline. On December 7, 2010, CH2M HILL inspected these same pipes after OMI re-cleaned them and found all pipe ends and they were unblocked. However, the flow path between the end of some of the pipes and the open water were still covered by mangroves. There are 7 main pipes that drain the salt pond at its east end, and these were observed to be flowing freely during the review. These are large (36-inch by 48-inch elliptical) corrugated pipes, and through probing with a shovel it was determined that there was little sand deposition in these pipes. These pipes are not covered by mangroves and there is a strong tidal current flowing through these pipes. The pipe located near the north end was starting to have some mangroves encroach on it, so this needs to be monitored. OMI provided the approximate location, type and size of the outfalls that they had cleaned. However, OMI did not have invert elevations. The City had survey data for only four of the

SEW/07112011-TM-FINAL.DOCX 7 ¡ CONST. & £ SURVEY

25' 25'

EXIST. R/W 50'

R/W LINE R/W LINE

2' SOD

10' 2' 11' 11' 5' 2' 7'

SHARED TRAVEL LANE TRAVEL LANE BIKE SOD USE LANE PATH

4" 4"

PGL 0.02 (MAX.) 0.02 0.02 0.02 0.02

CURB & GUTTER CURB & GUTTER TYPE F TYPE F " 2 1 TYPE B STABILIZATION LBR 40

TYPICAL SECTION BERTHA STREET

STA. 200+65.90 TO STA. 206+40.00

NEW CONSTRUCTION

OPTIONAL BASE GROUP 6 WITH

TYPE SP STRUCTURAL COURSE (TRAFFIC B) (2")

TRAFFIC DATA

DESIGN SPEED = 35 MPH

POSTED SPEED = 30 MPH

REVISIONS RODNEY C. DEVERA, P.E. MONROE COUNTY SHEET DATE DESCRIPTION DATE DESCRIPTION P.E. LICENSE NUMBER 71384 DEPARTMENT OF ENGINEERING NO. EAC CONSULTING, INC. ROAD NO. COUNTY FINANCIAL PROJECT ID 5959 BLUE LAGOON DRIVE, SUITE 410 TYPICAL SECTIONS (1) MIAMI, FL 33126 N/A MONROE 441959-1-54-01 6 CERTIFICATE OF AUTHORIZATION 7011 mpereira 11/8/2019 8:57:17 AM \\mia-fileprint\Project\Project\17 Project\17078.HW01-00 1st St. - Bertha St\CADD\roadway\TYPSRD01.DGN ¡ CONST. & £ SURVEY

25' 25'

EXIST. R/W 50'

R/W LINE R/W LINE

2' SOD 2' SOD

10' 2' 11' 11' 5' 2' 5'

SHARED TRAVEL LANE TRAVEL LANE BIKE CONC. USE LANE SWK. PATH

4" 4"

0.0 PGL 2 0.02 (MA X.) (MAX.) 0.02 0.02 0.02

CURB & GUTTER CURB & GUTTER TYPE F TYPE F " 2 1 TYPE B STABILIZATION LBR 40

TYPICAL SECTION BERTHA STREET

STA. 206+40.00 TO STA. 208+40.00

NEW CONSTRUCTION

OPTIONAL BASE GROUP 6 WITH

TYPE SP STRUCTURAL COURSE (TRAFFIC B) (2")

TRAFFIC DATA

DESIGN SPEED = 35 MPH

POSTED SPEED = 30 MPH

REVISIONS RODNEY C. DEVERA, P.E. MONROE COUNTY SHEET DATE DESCRIPTION DATE DESCRIPTION P.E. LICENSE NUMBER 71384 DEPARTMENT OF ENGINEERING NO. EAC CONSULTING, INC. ROAD NO. COUNTY FINANCIAL PROJECT ID 5959 BLUE LAGOON DRIVE, SUITE 410 TYPICAL SECTIONS (2) MIAMI, FL 33126 N/A MONROE 441959-1-54-01 7 CERTIFICATE OF AUTHORIZATION 7011 mpereira 11/8/2019 8:57:17 AM \\mia-fileprint\Project\Project\17 Project\17078.HW01-00 1st St. - Bertha St\CADD\roadway\TYPSRD01.DGN ¡ CONST. & £ SURVEY

25' 25'

EXIST. R/W 50'

R/W LINE R/W LINE 7.5' PARKING

2' SOD

6' 2' 6' 11' 11' 5' 2' 5'

CONC. TRAVEL LANE TRAVEL LANE BIKE CONC. SWK. LANE SWK.

4" 4"

PGL 0.02 0.02 (MAX.) .) 2 0.0 (MAX 0.02 0.0 2 0.02

CURB & GUTTER TYPE F CURB & GUTTER TYPE F " 2 1 TYPE B STABILIZATION LBR 40

TYPICAL SECTION BERTHA STREET

STA. 208+40.00 TO STA. 221+60.00

NEW CONSTRUCTION

OPTIONAL BASE GROUP 6 WITH

TYPE SP STRUCTURAL COURSE (TRAFFIC B) (2")

TRAFFIC DATA

DESIGN SPEED = 35 MPH

POSTED SPEED = 30 MPH

REVISIONS RODNEY C. DEVERA, P.E. MONROE COUNTY SHEET DATE DESCRIPTION DATE DESCRIPTION P.E. LICENSE NUMBER 71384 DEPARTMENT OF ENGINEERING NO. EAC CONSULTING, INC. ROAD NO. COUNTY FINANCIAL PROJECT ID 5959 BLUE LAGOON DRIVE, SUITE 410 TYPICAL SECTIONS (3) MIAMI, FL 33126 N/A MONROE 441959-1-54-01 8 CERTIFICATE OF AUTHORIZATION 7011 mpereira 11/8/2019 8:57:17 AM \\mia-fileprint\Project\Project\17 Project\17078.HW01-00 1st St. - Bertha St\CADD\roadway\TYPSRD01.DGN ¡ CONST. & £ SURVEY

25' 25'

EXIST. R/W 50'

R/W LINE R/W LINE 7.5' PARKING 7.5' PARKING

6' 2' 6' 11' 11' 6' 2' 6'

CONC. TRAVEL LANE TRAVEL LANE CONC. SWK. SWK.

4" 4"

0.02 PGL 0.02 .) (MAX.) 2 0.0 (MAX 0.02 0.0 2 0.02

CURB & GUTTER TYPE F CURB & GUTTER TYPE F " 2 1 TYPE B STABILIZATION LBR 40

TYPICAL SECTION 1ST. STREET

STA. 221+60.00 TO STA. 242+11.77

NEW CONSTRUCTION

OPTIONAL BASE GROUP 6 WITH

TYPE SP STRUCTURAL COURSE (TRAFFIC B) (2")

TRAFFIC DATA

DESIGN SPEED = 35 MPH

POSTED SPEED = 30 MPH

REVISIONS RODNEY C. DEVERA, P.E. MONROE COUNTY SHEET DATE DESCRIPTION DATE DESCRIPTION P.E. LICENSE NUMBER 71384 DEPARTMENT OF ENGINEERING NO. EAC CONSULTING, INC. ROAD NO. COUNTY FINANCIAL PROJECT ID 5959 BLUE LAGOON DRIVE, SUITE 410 TYPICAL SECTIONS (4) MIAMI, FL 33126 N/A MONROE 441959-1-54-01 9 CERTIFICATE OF AUTHORIZATION 7011 mpereira 11/8/2019 8:57:17 AM \\mia-fileprint\Project\Project\17 Project\17078.HW01-00 1st St. - Bertha St\CADD\roadway\TYPSRD01.DGN