Loading...
R7C-Accept Recommendation-Adopt 2011 Citywide Stormwater Management Master PlanCOMMISSION ITEM SUMMARY Condensed Title: A Resolution Of The Mayor And The City Commission Of The City Of Miami Beach, Florida, That The Mayor And City Commission Hereby Accept The Recommendation Of The Finance And Citywide Projects Committee And Adopting The 2011 Citywide Stormwater Management Master Plan. Issue: 1 Shall the Mayor and the City Commission approve the Resolution? Item Summary!Recommendation: The City of Miami Beach is one of 16 municipalities that entered into an lnterlocal Agreement with Miami-Dade County in 1993, authorizing Miami-Dade County to be the lead permittee in submitting a National Pollutant Discharge Elimination System (NPDES) Stormwater Permit Application. One condition of the lnterlocal Agreement requires Miami Beach to develop a Stormwater Management Master Plan (SWMMP) that is consistent with Miami-Dade County's Master Plan. In 1997, the City prepared a SWMMP that determined stormwater infrastructure needs based on water quality, flooding potential, City staff rankings, and complaints. The 1997 SWMMP has proven to be out-of-date as a result of changes in land use, modifications to the contributing watersheds as a result of re-grading and new construction, and sea level rise. The new SWMMP project has created a comprehensive, citywide model, using more powerful software than was available in 1997 that evaluates the existing system using survey data and Light Detection and Ranging (LIDAR) technology, simulates inter-basin flows, and identifies those basins that are experiencing a reduced level of service. Improvements are identified in a schematic fashion that provides one cohesive design for the City. The SWMMP also reviewed climate change and estimates of projected sea level rise. The consultant made use of a variety of published resources and analyzed historic sea level data. In particular, the consultant used data from the National Oceanic and Atmospheric Administration to determine the existing mean high water (MHW) and projections from the Army Corps of Engineers (ACOE) to estimate historical, intermediate, and high rates of sea level rise. The SWMMP uses the ACOE intermediate projection for sea level rise over the next 20 years. As a result, for all new projects, a sea level elevation of 0.67 feet NAVD88 (based upon the ACOE intermediate projection of sea level rise) is being used for stormwater design purposes and an elevation of 3.2 feet NAVD88 is being used as a minimum for seawall elevations. The previous design criterion required by the City was 0.04 feet NAVD88 for sea level elevation. There was no minimum seawall elevation. (Note NAVD88 is a vertical control datum established to define elevations). At the August 22, 2012 Finance and Citywide Projects Committee meetings, staff presented the SWMMP. The Committee approved the plan with the recommendation to use a 20-year planning horizon. THE ADMINISTRATION RECOMMENDS ADOPTING THE RESOLUTION. Advisory Board Recommendation: ! Approval by FCWPC Financial Information· Source of Amount Funds: 1 OBPI Total Financial Impact Summary: C1t Clerk's Office Le islat1ve Trackin MIAMI BEACH Account 245 Approved AGENDA ITEM ---..::R-'-1-L--C._ DATE 11-ll{-1'2.-. MIAMI BEACH City of Miami Beach, 1700 Convention Center Drive, Miami Beach, Florida 33139, www.miamibeachfl.gov COMMISSION MEMORANDUM TO: Mayor Matti Herrera Bower and Members of the City Commission FROM' Kathie G. Brooks, Interim City Manager~ DATE: November 14, 2012 SUBJECT: A RESOLUTION OF THE MAYOR AND THE CITY COMMISSION OF THE CITY OF MIAMI BEACH, FLORIDA, THAT THE MAYOR AND CITY COMMISSION HEREBY ACCEPT THE RECOMMENDATION OF THE FINANCE AND CITYWIDE PROJECTS COMMITTEE AND ADOPTING THE 2011 CITYWIDE STORMWATER MANAGEMENT MASTER PLAN. ADMINISTRATION RECOMMENDATION The Administration recommends adopting the resolution. BACKGROUND The City of Miami Beach is one of 16 municipalities that entered into an lnterlocal Agreement with Miami-Dade County in 1993, authorizing Miami-Dade County to be the lead permittee in submitting a National Pollutant Discharge Elimination System (NPDES) Stormwater Permit Application. (There are now 33 municipalities that are party to the lnterlocal Agreement.) One condition of the lnterlocal Agreement requires Miami Beach to develop a Stormwater Management Master Plan (SWMMP) that is consistent with Miami-Dade County's Master Plan. In 1997, the City prepared a SWMMP that prioritized drainage basins, recommended a five-year Capital Improvements Program, and provided hydrologic and water quality calculations for the priority basins. The 1997 SWMMP determined stormwater infrastructure needs based on water quality, flooding potential, City staff rankings, and complaints. The basins ranked the highest were made priority basins and received funding for stormwater improvements. Non-priority basins received no funding. The 1997 SWMMP has proven to be out-of-date as a result of changes in land use, modifications to the contributing watersheds as a result of re-grading and new construction, and sea level rise. Further, it did not provide a citywide model that could provide the data needed to plan comprehensive Citywide stormwater infrastructure improvements. At its June 9, 2010 meeting, the City Commission, via Resolution No. 2010-27 422, authorized Camp Dresser & McKee (now COM Smith) to prepare a new SWMMP. The draft is now complete (Attachment A is the Executive Summary for the Plan). 246 Citywide Storm water Management Master Plan November 14, 2012 Page 2 of3 ANALYSIS The new SWMMP project has created a comprehensive, citywide model, using more powerful software than was available in 1997 that evaluates the existing system using survey data and Light Detection and Ranging (LIDAR) technology, simulates inter-basin flows, and identifies those basins that are experiencing a reduced level of service. Improvements are identified in a schematic fashion that provides one cohesive design for the City. The SWMMP also reviewed climate change and estimates of projected sea level rise. The consultant made use of a variety of published resources and analyzed historic sea level data. In particular, the consultant used data from the National Oceanic and Atmospheric Administration to determine the existing mean high water (MHW) and projections from the Army Corps of Engineers (ACOE) to estimate historical, intermediate, and high rates of sea level rise. The consultant is basing its design recommendations on the ACOE intermediate projection for sea level rise over the next 20 years. The ACOE modified the equations for its curves in 2011. As a result, for all new projects, a sea level elevation of 0.67 feet NAVD88 (based upon the ACOE intermediate projection and an estimated sea level elevation of 0.29 feet NAVD88 as of 2009) is being used for stormwater design purposes and an elevation of 3.2 feet NAVD88 (a vertical control datum established in 1991 used to define elevations) is being used as a minimum for seawall elevations. The previous design criterion required by the City was 0.04 feet NAVD88 for sea level elevation. There was no minimum seawall elevation. The model has also been used to provide concurrency reviews of recently bid neighborhood improvement projects. These reviews have prompted changes to the stormwater designs of the neighborhoods due to inter-basin flows. As a result, the neighborhood improvements will be more effective in providing the required LOS and more flexible to account for the uncertainty relative to the rate of sea level rise. The neighborhoods reviewed to date are: • Biscayne Point • Central Bayshore • Lower North Bay Road • Lake Pancoast • Sunset Islands I & II In addition, the new criteria are being used in the preparation of the following projects: • Star Island • Palm and Hibiscus Islands • Sunset Islands Ill & IV • Sunset Harbour • Flamingo 61h Street • 161h Street • La Gorce Further, the SWMMP has developed order of magnitude cost estimates for the improvements required that total approximately $200 million in needed infrastructure improvements. These improvements will need to be made over an estimated span of 20 years, contingent upon the rate of sea level rise. It is important to note that the difference in cost from an earlier design estimate using a sea level elevation of 0.5 feet NAVD88 had a minimal cost difference to the revised sea level elevation of 0.67 feet NAVD88. 247 Citywide Storm water Management Master Plan November 14, 2012 Page 3 of3 At the June 28, 2012 Finance and Citywide Projects Committee, there was a technical discussion on the existing MHW and the rate of sea level rise. As a result, the Committee directed staff to have a public discussion on sea level rise and to return with the results. This SWMMP Sea Level Rise Discussion was held on Friday, August 17, 2012. The presentation (Attachment B) began with a discussion contrasting the City's previous SWMMP to the new SWMMP. The presentation then focused on sea level rise and the reports and data available to estimate MHW and the rate of sea level rise. Following this, the consultant discussed how sea level rise was incorporated into the draft SWMMP and into the recommended capital improvements. It was stressed that there is a large degree of uncertainty with the rate of sea level rise. As a result, the City has developed a flexible capital improvement plan that can accommodate various rates of sea level rise. The capital improvements will rely on backflow preventers at the outfalls, more pump stations, raised seawalls, and stormwater storage. The City will need to monitor the rate of sea level rise and adjust the plan accordingly. As sea level rises, the stormwater system will rely more upon pumps, and as the existing pumps age, they will be replaced with larger pumps. The presentation was generally positive with acknowledgement that the City is in the forefront of developing a capital program to address sea level rise projections. There were also some concerns expressed about the SWMMP. It was questioned why the consultant developed a master plan with a 20-year horizon instead of a 30-year or 50-year horizon. It was explained that the life cycle of a pump is approximately 20 years. After 20 years, a pump that has reached the end of its life cycle could be replaced with a larger pump depending on the rate of sea level rise. The consultant calculated the additional cost of the capital improvements for a 30-year time frame. While it requires larger pumps in certain locations, the 30-year time frame does not change the requirements for catch basins, piping, and seawalls and the difference in cost was $10 million. There were also questions about the ability of the City to deal with sea level rise beyond the 20-year or 50-year horizons. It was stressed that the SWMMP provides flexibility beyond the time horizons discussed. At the August 22, 2012 Finance and Citywide Projects Committee, staff presented the results of the Discussion (Attachment C) and an analysis of the costs differences between a 20-year planning horizon and a 30-year planning horizon. The Committee approved the plan with the recommendation to use a 20-year planning horizon. CONCLUSION The Administration recommends that the Mayor and City Commission adopt the resolution. Attachments: A. Stormwater Management Master Plan-Executive Summary B. SWMMP Sea Level Rise Workshop Presentation C. August 22, 2012 Finance and Citywide Projects Committee Presentation KGB/MAS/FHB/JJF/. T:IAGENDA\2012\11-14·12\Stormwater Management Master Plan· MEMO,docx 248 RESOLUTION NO.---- A RESOLUTION OF THE MAYOR AND THE CITY COMMISSION OF THE CITY OF MIAMI BEACH, FLORIDA, ACCEPTING THE RECOMMENDATION OF THE FINANCE AND CITYWIDE PROJECTS COMMITTEE AND ADOPTING THE 2011 CITYWIDE STORMWATER MANAGEMENT MASTER PLAN. WHEREAS, the City of Miami Beach is one of 16 municipalities that entered into an I nterlocal Agreement with Miami-Dade County in 1993, authorizing the County to be the lead permittee in submitting a National Pollutant Discharge Elimination System Stormwater Permit Application; and WHEREAS, one condition of the lnterlocal Agreement requires the City to develop a Stormwater Management Master Plan (SWMMP) that is consistent with Miami-Dade County's Master Plan; and WHEREAS, in 1997, the City prepared a SWMMP that prioritized drainage basins, recommended a five-year Capital Improvements Program, and provided hydrologic and water quality calculations for the priority basins; and WHEREAS, the 1997 SWMMP needs to be updated as a result of changes in land use, modifications to the contributing watersheds, and sea level rise; and WHEREAS, at its June 9, 2010 meeting, the City Commission, via Resolution No. 2010- 27422, authorized the City's consultant, Camp Dresser & McKee (now COM Smith), to prepare a new SWMMP; and WHEREAS, the SWMMP accounts for climate change and sea level rise; and WHEREAS, the new SWMMP establishes a comprehensive, Citywide model that simulates inter-basin flows and identifies those basins that are experiencing a reduced level of service; and WHEREAS, a SWMMP Sea Level Rise Discussion (the Discussion) was held on August 17, 2012, and included a discussion contrasting the previous SWMMP to the new proposed SWMMP; and WHEREAS, at the August 22, 2012 Finance and Citywide Projects Committee, following a presentation by City staff on the results of the Discussion, and an analysis of the costs differences between a 20-year planning horizon and a 30-year planning horizon, the Committee recommended approval of the new SWMMP, with the recommendation to use a 20-year planning horizon. 249 NOW, THEREFORE, BE IT RESOLVED BY THE MAYOR AND CITY COMMISSION OF THE CITY OF MIAMI BEACH, FLORIDA, that the Mayor and City Commission hereby accept the recommendation of the Finance and Citywide Projects Committee and adopt the 2011 Citywide Stormwater Management Master Plan. PASSED and ADOPTED this 141h day of November, 2012. ATTEST: Rafael Granado, City Clerk APPROVED AS TO FORM & LANGUAGE & F"'lli EXECUTION Matti Herrera Bower, Mayor T:\AGENDA\2012\11-14-12\Stormwater Management Master Plan-RESO.docx 250 .......................... Attachment A mmary 1 Introduction and und On June 9, 2010, the City of Miami Beach (City) authorized CDM Smith Inc. (CDM Smith) to develop a City-wide Comprehensive Stormwater Management Master Plan (SWMMP) in order to evaluate and update its storm water management practices, infrastructure, funding, and regulatory policies. Miami Beach is one of 16 municipalities that entered into an Interlocal Agreement (ILA) with Miami- Dade County in 1993 (subsequently 17 additional municipalities have also entered an ILA with Miami- Dade County), authorizing Miami-Dade County to be the lead permittee in submitting a National Pollutant Discharge Elimination System (NPDES) Stormwater Permit Application, which was required by federal law. One condition of the ILA requires the City of Miami Beach to develop a SWMMP that is consistent with Miami-Dade County's Master Plan. This report is the update and expansion of the SWMMP. The SWMMP is intended to be a guide for improving the City's stormwater management system performance for the next 20 years, with considerations of potential sea level change (SLC) over 20- years of stormwater infrastructure and a 50-year planning horizon for sea wall heights. SLC, to the extent it occurs, will worsen flooding potential in the by raising the water table and by making it more difficult to discharge stormwater out of the area. The SWMMP provides a preliminary schedule of prioritized capital improvements necessary to allow the City's stormwater systems: 1. to meet the increasing performance and regulatory demands 2. to modernize existing systems for both flood control and water quality 3. to maintain the City-desired flood control level of service (LOS). The City is a highly urbanized coastal community located in southeast Florida and is a major economic resource to the region. Bounded by the Atlantic Ocean and the environmentally sensitive Biscayne Bay Aquatic Preserve, which is also an Outstanding Florida Water (OFW) requiring strict environmental protection, the study area covers approximately 4,200 acres. The area has relatively low-lying land that is intersected by intracoastal waterways with limited natural storage and large areas of re- development. The subtropical climate entails high-intensity rainfall and significant tidal influence. These factors all contribute to historical and potential future severe rainfall and tidal flooding. .2 Progra and Obj Specific objectives of the SWMMP were defined through the initial project meetings to identify adaptable and sustainable stormwater management solutions that: • Objective No. 1: Quantify and improve flood control LOS, that is, the degree of flood protection achieved, based on a 20-year capital improvement program; • Objective Number 2: Quantify economic impact of flooding; • Objective No.3: Facilitate and prioritize operation and maintenance (O&M); " Objective No.4: Augment existing infrastructure for storage and treatment; © 2012 CDM Smith All Rights Reserved 251 ES-1 Executive Summary ,. Stormwater Management Master Plan " Objective No. 5: Coordinate and guide review of projects under current design/construction and facilitate accelerated analysis of "early out" projects; " Objective No.6: Identify stormwater harvesting-reuse and recharge well opportunities for conservation of fresh water; • Objective No.7: Refine and recommend updates to the City's stormwater ordinances and assess sufficiency of the City's Stormwater Utility; and " Objective No. 8: Provide recommendations for seawalls to mitigate the effects of sea level increases over the next 50 years . . 3 ethod As part of this SWMMP, surface water modeling was performed using the EPA Stormwater Management Model (SWMM) to estimate and evaluate existing flooding LOS and alternative solutions to meet refined LOS targets. Water quality evaluations were conducted using the COM Smith Watershed Management Model (WMM). These tools can be used to support design and implementation. Model development came from a multitude of resources. The following is a list of some of the data sources: " Actual rainfall data collected from rain gages throughout the City and at Miami International Airport " Design storms as defined by SFWMD and other methodologies (i.e. FOOT) " South Florida Water Management District (SFWMD) and City land use plans " Subsurface and geotechnical information obtained from the Natural Resources Conservation Service (NRCS) and projects under design by other consultants for the CIP Office " Mean high tide elevations at Virginia Key collected by the National Ocean Service (NOS) which is a branch of the National Oceanic and Atmospheric Administration (NOAA) " Miami-Dade County and privately sourced aerial mapping of the City • Light Detection and Ranging (LiDAR) data from SFWMD • LiDAR data from Miami-Dade County '" Models developed by other consultants for projects currently under construction or with construction completed for the City's CIP Office and the Florida Department of Transportation (FDOT) • Basis of Design Reports and design plans developed by other consultants for FOOT and projects currently under construction or with construction completed for the City's CIP Office " Construction record drawings for construction completed for the City's CIP Office • Survey data collected by the CDM Smith team's topographic surveyor, Hadonne KM3226ESdocx © 2012 CDM Smith All Rights Reserved 252 ES-2 Executive Summary ~ Stonnwater Management Master Plan " Neighborhood surveys developed by the City • Geographic Information System (GIS) coverages of the City, which are maintained by the City's Information Management System (IMS) CDM Smith used the United States Army Corps of Engineers (USACE) guidance document (Engineering Circular 1165-2-212: Sea-Level Consideration for Civil Works Programs) for incorporating the direct and indirect effects of projected future sea level change (SLC) across a projected 20-year project life cycle. The USACE guidance document presents an approach for planning studies and engineering design for evaluating a range of possible future rates of SLC, represented as three equation-based scenarios (or curves): low, intermediate and high. CDM Smith performed sensitivity analysis by evaluating the three scenarios to maximize the benefits of the recommendations under varied degrees of potential future SLC. Evaluation of LOS performance and adaptability of the SWMMP-recommended system are based on the intermediate scenario (curve), which based on the 20-year life cycle is projected to have a tidal mean high water condition of approximately 0.67 ft. NAVD. However, adjustment calculations have been performed for the high projections (0.84 ft. NAVD) in the instance that SLC accelerates (figure 1). This SLC sensitivity analysis included a variety of mean high tide elevation predictions over the next 20 years in combination with SFWMD defined design storm events. As a complement to the engineering evaluation, CDM Smith utilized the Federal Emergency Management Agency's (FEMA) Hazards United States (HAZUS) tool designed to estimate hazard- induced losses for use by federal, state, regional and local governments, and private enterprises in planning for risk mitigation, emergency preparedness, response and recovery. using a standard FEMA tool, the City will benefit in the coordination of future activities related to flood proofing, grant assistance, and management of repetitive loss properties. The analysis, which was performed for South Beach, incorporated existing elevations, structure and land use data along with information from the detailed flood model (SWMM). The HAZUS model generates an output that consists of a damage amount in dollars that is based on the percentage of total value loss a structure incurs during a flood event, like the statistically calculated once-in-S-year storm (5.9 inches of rainfall in 24 hours). level of The primary purposes of LOS criteria are to protect public safety and property. Program goals are to maintain passable roads for emergency and evacuation traffic during 5.9 inches of rainfall in 24 hours and to keep flood stages below the first floors of homes and buildings. The LOS criteria were first used to identify and define potential problem areas using the stormwater model developed for this study. The LOS criteria were then used to evaluate the effectiveness of contemplated improvements. LOS achievement decisions directly affected the size and cost of proposed improvement alternatives. Improvements and 1ons CDM Smith developed recommendations and proposed modifications to language included in the City's Public Works Manual, City ordinances, and policy documents. Implementation of these modifications should be coordinated with the various City Departments including Public Works, CIP, Planning, City Attorney, Finance, Budget and Performance Improvement, and the City Manager's Office. Recommendations were made based on the following major categories: .KM3226.ES.docK © 2012 CDM Smith All Rights Reserved ES-3 253 N CJ'I ~ USACE curves are based on the Circular EC 1165-2-212, 0.9 -~-USACE NRC Curve I 0.8 _ .... USACE NRC Curve llltntor~ @ ""dr»w USACE NRC Curve Ill 0.2 0.1 0 1980 !>:'M~nf>FSdno: © 2012 CDM Smith All Rights Reserved Key Tidal Data 1:1.16 NOM 1985 1990 1995 Armua!!zed "'w~'~'= NOM Data 2000 2005 Year Executive Summary " Stormwater Management Master Pl;m on October 1, 2011 and 2.013. 2010 2015 2020 2025 2030 Historic and Proiected Mean Water Levels at ES-4 Executive Summary " Stormwater Management Master Plan • Data Management • Stormwater Models and Future Condition Analysis In recognition of SLC, tidal conditions for future modeling efforts should utilize tidal boundary conditions as defined by the latest version of the SWMMP. This version of the SWMMP recommends a tidal boundary condition of 0.67 ft. NAVD. It is based on USACE guidance intermediate scenario projections for SLC based on a current day (Year 2009) mean high water elevation at 0.29 ft. NAVD and a projected Year 2030 mean high water elevation at 0.67 ft. NAVD (See Figure 1). " Stormwater Harvesting and Reuse " Sea-Level Rise Considerations The SWMMP recommends the City monitor SLC phenomena and possibly participate with local and regional climate change advisory committees regarding regional recommendations related to SLC. " Seawall Height Considerations In recognition of SLC and seasonal (Fall and Spring) annualized mean higher high tidal elevations of 1.6 ft. NAVD (Year 2009). The SWMMP recommends based on the USACE guidance intermediate scenario, the establishment of a minimum seawall height of 3.2 ft. NAVD, which provides greater than 50 years of sea wall protection against future mean higher high tidal elevations. " Pump Station O&M " Storage Facility Standards and O&M " Outfalls/Backflow Preventer Standards and O&M 11 Recharge Well Standards and O&M 11 Swales O&M • Exfiltration Trench O&M " 100-Year Floodplain Storage • Stormwater Design Standards 6 Proposed Improve ents and Proje rdination Evaluations were performed for project areas to determine the level of infrastructure improvements necessary to meet the LOS for the statistically calculated once-in-S-year storm LOS. A tiered Best Management Practice (BMP) treatment train approach was used to identify the most effective solutions for each project area and to identify opportunities for flood control, water quality, aquifer recharge, and stormwater harvesting and irrigation use. The tiered approaches were incrementally formulated from the simplest tier 1 (e.g., back flow preventers) through the most complex and costly tier 4 (e.g., underground storage), and bundled together to determine the economic feasibility of © 2012 CDM Smith All Rights Reserved 255 ES-5 Executive Summary " Stormwater Management Master Plan proposed infrastructure improvements. Due to the anticipated significant capital investment and stringent permitting to discharge into Biscayne Bay, the tiered approach should allow the City to proceed with specific elements of the BMP treatment train as economic conditions permit. This would allow for future addition of tiers to ultimately meet the full 5-year LOS while monitoring and adjusting to sea-level rise conditions. .7 Proj nking and m end 1ons The results of the flood damage analysis using the HAZUS tool showed that the existing topographic conditions in Miami Beach have significant potential economic losses associated with flood events, for both rainfall-induced and tidally-induced events with the implementation of a Capital Improvement Program (CIP). A prioritized stormwater CIP list based on the ongoing projects and problem areas identified in the SWMMP was developed. In addition, COM Smith provided recommendations regarding overall stormwater management needs to achieve better O&M, policies, and standards for existing and future conditions. Three project categories have been identified: " Out (Near-Term Implementation) Projects and Currently Scheduled CIP Projects; " Concurrency-Reviewed (Review of Projects Currently Under Final Design and Construction) CIP Projects; and " SWMMP-Identified Projects. COM Smith recommends approximately $196 million in capital improvements (based on 0.5 ft NAVO (low scenario) to 0.67 NAVO (intermediate scenario) mean high water tidal conditions) proposed for the City's primary stormwater management system. CDM Smith has incorporated an additional sea- level rise adjustment of approximately $10 million to account for the potential phenomena of accelerated sea-level rise (up to 0.84 ft NAVD mean high tidal conditions) (high scenario), and subsequent additional stormwater facility needs. COM Smith also reviewed O&M costs associated within these identified capital projects. Table ES-1 shows the locations, timeframes and capital costs of the proposed projects. KM3226.ESdocx © 2012 CDM Smith All Rights Reserved ES-6 256 Executive Summary ,. Stormwater Management Master Plan Table ES-1 City of Miami Beach Stormwater Management Master Plan Capital Costs (in Million $) •under design The CIP was also evaluated both technically (SLC) and financially (capital cost) based on a 30-year planning horizon. However, given the design life of the pumping components and CDM Smith's experience in the development of other SWMMP, it was concluded that a 20-year planning cycle was appropriate with continued monitoring of SLC in shorter time increments. The financial analysis of the City's Stormwater Utility shows that it will require additional funding to finance the construction of recommended CIP projects and to operate and maintain the system over the next 20 years. The submitted SWMMP provides comprehensive recommendations for improving the City's stormwater management system performance for the next 20 years. Appropriate consideration has been given to potential sea-level rise, water quality of Biscayne Bay, and O&M of an expanded system. The presented capital improvements allow the City's stormwater systems to be flexible and adaptable in meeting the increasing LOS performance targets and regulatory demands. Specific objectives were defined through the initial project meetings, including the following; the means by which the SWMMP addresses them are also noted. • Objective Number 1: Quantify and improve flood control LOS based on a 20-year capital improvement program; SWMMP Solution: A comprehensive 20-year CIP was developed quantifying improvements to flood control LOS with flexibility to adapt to varying degrees of SLC; • Objective Number 2: Quantify economic impact of flooding; SWMMP Solution: HAZUS evaluation documents the economic impact of flooding on the region of the City that generates the majority of the City's tourism revenue. The $196 © 2012 CDM Smith All Rights Reserved 257 ES-7 Executive Summary " Storrnwater Management Master Plan million CIP quantifies the economic requirements to meet LOS. Increasing the CIP to $206 million provides a financial adjustment to accommodate higher SLC projections; • Objective Number 3: Facilitate and prioritize O&M; SWMMP Solution: Refinements and expansion of current O&M practices have been evaluated with a projected cost as part ofthe development of recommendations. These considerations are included in projected future funding of the City's Stormwater Utility; • Objective Number 4: Augment existing infrastructure for storage and treatment; SWMMP solution: The BMP Treatment train tiered solutions augment the existing infrastructure with storage and treatment solutions; • Objective Number 5: Coordinate and guide review of projects under current design/ construction and facilitate accelerated analysis of "early out" projects; SWMMP solution: Early out projects have been developed and concurrency reviews have been performed to guide the development of stormwater solutions under construction that are consistent with the SWMMP; • Objective Number 6: Identify stormwater harvesting-reuse and recharge well opportunities for conservation of fresh water; SWMMP solution: Tier 1 through Tier 4 BMP Treatment Train recommendations recharge the Biscayne Aquifer under the City while developing storage solutions that promote irrigation and reuse of treated stormwater; • Objective Number 7: Refine and recommend updates to the City's stormwater ordinances and assess sufficiency of the City's Stormwater Utility; SWMMP Solution: Recommendations to refine ordinances and policies including those related to SLC are proposed while identifying the long-term revenue sufficiency of the Stormwater Utility; • Objective Number 8: Provide recommendations for seawalls to mitigate the eflects of sea level increases over the 50 years; SWMMP Solution: Preliminary inspection and elevation standards for seawalls have been made with consideration of SLC, based on USACE guidance documents. The presented SWMMP addresses the objectives defined at the initiation of the project. The developed solutions are consistent with the project statement defined at the project kickoff meeting: "Proposed solutions are needed that are accurate, timely, effective, and defensible." © 2012 CDM Smith All Rights Reserved 258 ES-8 N CJ'I <0 In 1997, The Stormwater Plan. Old Plan determined needs by: • Water quality • Flooding potential • Citizen complaints • City staff ranking New Plan dotcrmines needs by: •Data collection New Draft Stormwater Management MasterPlan • Accounts for sea level rise • Makes recommendations for 20·year capital improvements • Provides flexibility for various rates of sea level rise • Provides drainage analysis using modeling GOING FORWARD Implement Stormwater System Improvements • Install backflow preventers at outfai!s • Construct new stormwater pump stations • Add pumps to gravity systems • Create storage for stormwater • Raise seawalls to mandatee heights Monitor change in sea level rise; Modify programmed stormwater improvements 10/31/2012 r:rJ N 0') 0 international ! nternational -'!YY;f!Li,;P!~§!iJJ.iiYJlem;s; consulting firm Waterfront Projects Over 20 Years as consulting firm in South Florida Project~ in Florida, Caribbean, and Central America Tim Is Director of Engineering for Coastal Systems With firm for over 12 years 20 Years ot Experience-coastal, civil, marine structural engineering Beach Management Projects-Miami-Dade Tidal Hydraulic Studies-Riscayne Bay and S. Stormwater Management Design-Miami Beach ASCE Florida Infrastructure Report Card Committee-Coastal Areas-2008 10/31/2012 Tidal Boundary Conditions-Coastal Systems International Introduction Role of Coastal Systems on COM Smith Team Review of Key Terms and Defnltions Drainage Outfall Design Criteria Reference Tide! Datums Historical Tidal Data Analysis Sea Levei Rise Trends Recommendations to COM Smith Team Subconsuitant to COM Smith -Coastal Engineering analysis Biscayne Bay and Effect on Drainage Tidal Data Analysis 2 N 0') ~ ., '"., . Tidal Boundary Cond:tions: B:SC.Avr-,1!;:: BAV Definitions included in workshop handouts Visit NOAA web site WW\¥Xdesandcurrents"noaa"gov Tidal Boundary Conditions-Design tidal elevation at Biscayne Bay for drainage outfall hydraulic analysis NOAA-National Oceanic and Atmospheric Administration NAVD-North American Vertical Datum of 1988-geodetic vertical datum Water-The average of all the over the National Tidal Datum Current Tidal Epoch -based on data from 1983-2001 e-r~cr Mi.A.!V!: e::;;A(:.:-DRAiNAGE SYST.::l'v'! water 10/31/2012 WaterNays are Tidal T:dal Boundar; Ccmdit!ons: 3 N 0') N NOAA Tide • The Florid;;; Department of Tid;;. Bebw CMfa!i the East Coast of Transportation ( FDOT, 2012) requires the use of MH\IV !or culvert drainage d.,;sign ~ le'h~·J ~ tf@Xt with water levei data 10/31/2012 Water [NAVD, It] -!,86 -US -2,88 Current Tidal Epoch-based on data from 1983-2001 4 N 0') w Q(J.] i '~ ~ "' -;; ~ !'J'i); 20()(.\ ;'\ltl:'. \'eur Trend from observed daia is 0.118 inches/year 2 ~ t (J w -3 (1 t:: t"'l4 ·~ 334 1''"'-' Y""!.!r Trend from observed data is 0.118 inches/year 10/31/2012 :<>~f) 50-year i 00-year 0.85 i .34 5 N 0') ~ 1BOO 1850 1900 1950 2000 2050 2100 Source: I PC, 2007 Minimum Condition Virginia Key. Criteria 0.36' NAVD for Soundarv annual water levels observed at from 1999 data. 25-Year Projection is 0.41' NAVD Iterative Analysis to evaluate practicality and cost-effectiveness of stormwater management system and design that accounts for these minimum and MHWievels Sea Level Trends: 0.65' to 1 .66' MHW Elevation in 50 Years (CSI Projection, 2011 and CCATF Recommendation, 2008) Shoreline Elevations should be Reviewed Michael F. Schmidt, P.f., BCEE Senior Vice President for CDM Smith \<Vater Resources Technicai Market leader with 27 years experience on +80 storrnwater programs across Fiorida Managed /directed +160 water resource management programs Jason A. Johnson, I'. E. Senior Project Manager Principal Water Resources Engineer 15 years of international and domestic water resources/ stormwater management experience 10/31/2012 6 N 0') CJ1 . ·>>"·''''·; :: : ~·::v~i'ii ;Efj;\, :; ~~j:~ii; Stermw~r·M:ast~t;Rian·Goals ~ ' ' ' '"" " ' "" '' y' ,, ', ' ' '/ ' " ,'"" ',,' Adaptability Level of Service • Keep beiow homes and • Keep roads passable for emergency traffic as Terms and Definitions • Design Storm • Boundary Condition • Level of Service • • Best Management Practice (flMP) • Backflow Preventer • Outfa!l • Well • Reuse • IPCC • USACE City of Miami Beach Stormwater Issues • Low and relativelv flat terrain • Limited pervious area -Existing development -New construction " Tdal constraints and backflow • High groundwatertable • Aging infrastructure in corrosive conditions 10/31/2012 7 N 0') 0') • Evaluate current tidal guidelines and requirements by other Government agencies: • USACE «> SFWfv1D • NOAA • FDEP <il USGS • FOOT • FEMA ~~ Miami~Dade Co\Jntv • Evaluate 20 year for sea level rise -Use local data, when possible (i.e. Virginia Key) -Sensitivity analysis to tidal and ra;nfall conditions -Adaptability to varied sea-level rise projections (i.e. LJSACE guidance document) C/ly#III/Jiirlii~~~.Mim«rl'lt!t ~:~'~·············· -~ " ' ""..:...;;' :..;__:_-~~:z.t Biscayne Po:nt North Shore North Shore (72~d Street) Nocrnandy is!e Upper L>Gorce Low<i:r LaGor::.e LaG.:m::e/Aili~on l~l.;;nJ Oceanfront Nautilus Sunset Islands 3 & 4 Fiarntngo+ SUBTOT.4L Adjustment for highest sea I eve! rise projection $11 $7 $10 $20 $12 $14 $9 $0 3 $4 $3 $106M $196iv1 S10M Ort<I!III/Jiirlii-~~~1'/M .·! l ~~ Histori~.ancfi~rc>Jecteti:M~anHi~~W~t~i~~l$;~,;:.':!.ii Virgioia Ke,y. ·• .•. ::,·-;! ·{~: .. '~i ·-@-NO.AAEvoch m;; U5.1K.F ~'-HV<:Co ,Jr,; b<~;<:tJ,_,,, tl,e Er.giPeer•ngC:r~ui,11 f'"bli~'l~d Nl Octab<:r-1 2011 cmd tY;:mu :>r:plr!'T'bl! lj<! ·;·,··;,," .. ".'-i" "·;.i .. /' :Oi'" ... ;;.;of:.;-,F.·•:·:·Y:'"·;:;·::" , '; ·; ,o; ·.·;. Tlered Be$.Management·P'rattk:e .. ~sMP:}Ttea~ef'.ltf;;: Trairt'ApprQach Prhvid~ .. 4~P~~ii~ . . ..... Lower Cost atr4/_i!oildr_..._,~~~ 10/31/2012 8 N 0') ....... 32 into separate slides. keep the full slide and then add the steps in subsequent slides N 0') 00 ri~r~9 BE!~M~ .. ·; . Train APfll"Q{lch':Pr . ' ; ' ' {-;"'; ,/ ~' ',' "' ,, '';'' ,, ;'' ', /~? /' n '' Runoff and load Generation Tiered Best Management P~ctib~ (BMP} Treatment. . ~ . Train Approach Provides Ad(iptabiiity (cont.) ... ·.· Additional Treatment, Attenuation, &. Rechargl:'! Q~yl!f~~~~.I(;,:IJ;iJ~J·l/ Tiered BestManagentent. P~ctic~ {BMP} Tr~atro~nt. Train Approach Provides Adaptability (cont.} .. •·. • Tiered Best Managemen~Practi~e (s~P)Treatment . Train Approach Provides Adaptability {cont.) .. 1 Final Treatment, Attenuation, &Reuse .ctt¥"1'--~-~~~ r 1 ~..~:11'1!11 2 9 N 0') <0 Tiered Best Management Pr~ctice;(~MP)Treatment ·. Train Approach Provides Adaptability (cont.) ··Outfall atvct--$-~Mi>lt«l'l{m ~~=~M-atygf-III<Dth~IO<~Mt;stn~ Rec::omm~JJqatt~1:ff'()~d· P'ReiaeJa:i~;:;· · Sea~level Ri~e • Monitor and participate in future regional recommendations related to sea level rise • Follow USI\CE Civil Works and FEMI\ and in planning • Monitor pending IPCC recommendations regarding sea-level rise that are scheduled to be released to the oublic within the next three years • Review Udal data every five years and adapt the SWMP as appropriate Clty;;f-s-Jt~r-l'IM. 10/31/2012 10 N ....... 0 As 8 resuH. the Committee airected staff to have a publ;c discussion on sea level rise and to return with the resuits This SWMMP Sea Level Rise Modify storrnwater system as sea !eve! rises • instai! backfiow preventers at outlai!s • construct new stormwater pump stations • add pumps to gravity systems ~~ r.reB.te storage for stormwater • raise seawails to mandated heights Monitor change in sea level and refine luture adaptation strategies Re-prioritize ;nlrastructure requirements lt\ "!!!!!' 1 0/31/20'1 2 ;J::l rt" rt" Ill 0 ::r a ro ~ rt" n • I