City of Naples Stormwater Master Plan Update

Transcription

1 City of Naples Stormwater Master Plan Update 60% Submittal Review September 6, 2017 Presented by AECOM, AMEC Foster Wheeler, and Angie Brewer & Associates

2 Agenda Introductions Background Objective Goals Components of the Stormwater Master Plan Preliminary Findings Next Steps Page 2

3 Introductions AECOM Amy Eason, PE AMEC Greg Corning, PE and William Tucker, PhD Angie Brewer and Associates Kevin Sudbury Other Team Members Cella Molnar Special Thanks to the City Staff!!!! Page 3

4 Why Stormwater? The City of Naples receives an average annual rainfall of 55 inches which equates to approximately 13 billion gallons of water in a year. Stormwater is discharged into the Gulf of Mexico, Naples Bay, Moorings Bay local lakes and waterbodies, and groundwater. Many private properties have stormwater management systems that detain or retain stormwater. These systems must be maintained. City infrastructure conveys and treats the stormwater. Page 4

5 Why do we need a Stormwater Master Plan? Stormwater runoff is an increasingly important resource that needs to be managed from both a water quantity and quality standpoint. A plan allows the City to record and evaluate current stormwater management practices. Allows the City to establish goals and provide a foundation for future policy decisions. Establishes Capital Projects for the next 10+ years. Aerial of the City of Naples Page 5

6 Background 1996 Stormwater Master Plan prepared by City Staff 1998 CDM prepared Assessment Report on Basin CDM prepared Design Development Report for Basin CDM prepared Interim Report on Basin Staff updated Council on status of 1996 plan ($42M) 2007 TetraTech prepared Stormwater Master Plan ($78M) Page 6

7 Objective The objective for this plan is to develop a clear, comprehensive, and forwardlooking master plan (updated from 2007) that encompasses Naples stormwater management program, presents a detailed investigation into key components of stormwater as it is related to the City, establishes goals and provides a foundation for future policy decisions. This Stormwater Master Plan Update will help the City guide its stormwater management program for the next 10 or more years. Page 7

8 Goals The goals of this Stormwater Master Plan Update are: protection of the health, safety and welfare of City residents protection of and improvement to the City s surface and ground water resources protection of public and private property protection and restoration of ecology planning wise and strategic investments into the storm water management system. Page 8

9 Which components are being evaluated in the Stormwater Master Plan? Water Quantity (Flooding) Water Quality and Ecology Level of Service Regulatory and Development Code Review Climate Adaptation Best Management Practices (BMP) Review Operational Strategies Capital Improvement Program Funding Stormwater & Natural Resource Divisions Public Involvement Page 9

10 Information and Data Collection Drainage Studies Master Plans Other Relevant Sources Federal Emergency Management Agency (FEMA) U.S. Geological Survey (USGS) National Oceanic and Atmospheric Administration (NOAA) South Florida Water Management District (SFWMD) Florida Department of Environmental Protection (FDEP) Big Cypress Basin Board Collier County City of Naples Page 10

11 Data Collection Hydrologic Data Rainfall Data Tidal Data Groundwater Data Basin Data Neighborhoods General geography Topographic Future land use and zoning Soil Information Stormwater Infrastructure Page 11

12 GIS Data A comprehensive GIS system inventory improves the ability of the City to study the infrastructure system in relation to other datasets available in GIS, such as planning data, flood zones, capital improvement projects, water, wastewater, and reuse systems. This information is not only critical to proper project planning and design, but can be useful in evaluating the value of the stormwater management assets for accounting purposes. In addition, aids in determining issues when it comes to operation and maintenance. Page 12

13 GIS Preliminary Recommendation Reconcile data For example, swales appear to be identified as open drains perhaps that can be identified as swales. Minor water bodies can be identified as the identified water body. For example, the entire data set has to be reviewed to find a named Lake Review the attribute data insure that proper data is being collected Contract a surveyor with GPS equipment or an engineering firm with a GIS department that can collect asset data Page 13

14 Water Quantity General Information FEMA Floodplain Mapping Types of Flooding o Tailwater and Tidal Issues o Primary Conveyance Issues (Canals, Ditches and Major Culverts o Secondary/Tertiary Conveyance Issues (Ditches, Swales, and Minor Culverts) o Renewal and Replacement (R&R) Deficiencies o Inlet and Structure Inadequacies (Throat Capacity & Spacing) o Operation and Maintenance Deficiencies o Groundwater Flooding Basin Assessments Page 14

15 FEMA Map Page 15

16 Basin Assessments Reviewed any existing basin studies Reviewed FEMA maps Reviewed topographic information and overlaid the complain database and the repetitive loss structures Identified potential causes of issues Low Topography Small Discharge Pipes No conveyance system inlets and pipes No swales Page 16

17 Example Assessment Page 17

18 Repetitive Loss Area Analysis Repetitive loss structures are building structures that have been subjected to insurance claims to flooding at least twice in 10 years with claims in excess of $1,000 Two general areas according to City: Area 1 16 th Avenue South Only 1 repetitive loss structure (Pre-FIRM) and 1 additional structure with a flood claim Area 2 9 th & 10 th Avenue South Only 1 repetitive loss structure (Pre-FIRM) Page 18

19 Repetitive Loss Area Analysis Basin Number of Claims Claim Paid Total Claims Paid = 16 between 2007 and now Last update = 18 claims Page 19

20 Water Quantity Preliminary Recommendation Complete the recommended Capital Improvement Projects identified in the Capital Improvement Section to help address localize flooding issues Complete Basin Assessment for all basins. Page 20

21 Water Quality and Ecology I. Receiving Waters and Inputs 1. Naples Bay i. Golden Gate Canal (150 million GPD) ii. Upland stormwater iii. Gordon River iv. Rock Creek v. Haldeman Creek 2. Gulf of Mexico i. Beach outfalls ii. Naples Bay iii. Moorings Bay 3. Moorings Bay i. Upland stormwater 4. Gordon River i. Golden Gate Canal ii. Upland stormwater 5. Upland surface waters Page 21

22 Water Quality and Ecology II.Review of Existing Data 1. Relevant documents published since the 2007 SMP were reviewed i. Most were prepared by the City with contractor support, in addition ii. Relevant FDEP and SFWMD reports 2. Some important findings i. The City has collected valuable water quality and ecological data since 2007 ii. The City has evaluated and used these data to 1. Improve understanding of water quality concerns affecting, and affected by, the City 2. Develop action plans by City staff to be considered for incorporation in this Plan update iii. Critical regulatory developments (FDEP) have occurred since 2007 Page 22

23 Water Quality and Ecology II.Review of Existing Data 3. Summary of Identified Project Needs i. Description of City of Naples Stormwater System ii. 1. The stormwater system includes BMP such as storm sewers, water control structures, rain gardens, vegetated swales, filter marshes, and 28 stormwater retention ponds. Of those 28 lakes, 23 are private or undetermined; and 5 are on City property 2. Since 2007 the City has constructed or supported community actions to increase number of rain gardens and swales, constructed filter marshes, and made stormwater lake improvements, e.g. Lake Manor Restoration Stormwater System Project Needs 1. Continue to implement additional BMPs as identified above 2. Update the Stormwater Lakes Management Plan 3. Resources required to maintain BMPs increase as they age or additional BMPs are constructed 4. Excess nutrient levels in Naples Bay have been reduced, although levels of copper and bacteria have increased 5. City staff educate and assist citizen actions now, but the City does not have a comprehensive environmental outreach program Page 23

24 Water Quality and Ecology III.Regulatory Standards Affecting the Stormwater Management Plan Page 24

25 Water Quality and Ecology IV. Evaluation of the City s Water Quality Monitoring Program 1. Past and Current Water Quality and Biological Monitoring Programs i. City monitors surface estuarine waters in Naples Bay, the Gordon River, Moorings Bay. These data are used by FDEP to evaluate the quality of waters of the State ii. City monitors upland stormwater lakes (15 of 28) and pump stations iii. City monitors fish populations and seagrass beds in Naples Bay iv. Parameters include turbidity, salinity, temperature, DO, nutrients, bacteria, and metals Page 25

26 Water Quality and Ecology IV.Evaluation of the City s Water Quality Monitoring Program 2. Summary of Water Quality and Biological Data i. Several local, state, and federal agencies participate ii. iii. 1. City of Naples, Collier County 2. SFWMD, FDEP 3. USGS, NOAA Increasing trends for copper, chlorphyll-a, turbidity, and fecal coliform bacteria Decreasing trends for total nitrogen (TN) and total phosphorous (TP) 1.2 Annual Copper Frequency Above 3.7 µg/l CURLEW GORDEXT HALDCR NBAYNL NBAYWS OYSBAY ROCKCR Page 26

27 Water Quality and Ecology IV.Evaluation of the City s Water Quality Monitoring Program 3.Recommendations for Improvement of the Water Quality and Biological Monitoring Programs i. Recommendations in the 2015 City report Naples Bay Monitoring Design should be implemented contingent on partnerships with cooperating agencies and funding sources. ii. These include: 1. Partner with SFWMD and Collier County to improve monitoring of discharge from Golden Gate Canal, Rock Creek and Haldeman Creek. 2. Modify features of the Naples Bay biological monitoring program Page 27

28 Level of Service (LOS) Analysis Level of Service represents degrees of protection provided for various development and natural features expressed in terms of storm events to be accommodated by the applicable drainage facilities. Water Quantity LOS protects the public and property from flooding Water Quantity LOS protecting surface waters from erosion and degradation Page 28

29 LOS Water Quantity Policy 1-10 states that the LOS standard for surface water management for all development, redevelopment and the primary drainage systems requires no flooding during a 5-year, 1-hour storm event for roads, yard drainage, pump stations and trunk lines and requires no flooding during a 100-year storm event for building finished floor elevations. Policy 1-11 states that all new development, redevelopment or substantial improvement of platted properties within the City shall be reviewed to assure compliance with local ordinances, design criteria and building code requirements, which include stormwater management systems to be constructed to minimum standards. This policy includes single-family, multi-family and non-residential mixed use properties. Page 29

30 LOS Water Quantity Section Stormwater construction standards. Any new development, redevelopment or substantial improvement of platted properties within the City of Naples shall be reviewed to assure compliance with the following minimum stormwater design criteria: GOAL A Unless otherwise specified by previous South Florida Water management District (SFWMD) permits or District criteria, a storm event of a one-hour duration and 5 year return frequency shall be used in computing the minimum off-site discharge rates from private properties to the City s stormwater system. The stormwater conveyance system should be designed sufficiently so that the conveyance shall pass the design flow while ensuring that the backwater head does not exceed the proposed berms, walls or other containment systems in a twenty five year 24 hour storm event. The side lot swales and other emergency conveyance facilities may be designed to pass the water forward to the Public Right of way. Page 30

31 LOS Water Quantity Preliminary Recommendations Conduct a Basin by Basin analysis to determine what the existing level of service should be and then evaluate whether the LOS can be greater due to capacity and storage Evaluate if a tiered system is needed. (redevelopment versus new development; commercial versus single family residential versus multi-family) Page 31

32 LOS - Water Quality I. Water Quality LOS 1. Existing requirements for pollution abatement i. BMAPs and TMDLs Table 6.2. TMDL Summary Table TMDL Name/ID Water -body Class Acres Basin City of Naples Stormwater Major Basin Nutrients included in TMDL (or impairment) Causative Pollutant (parameter) Requirements of TMDL BMAP o New Construction Standards Gordon River Extension, WBID 3278K (formerly 3259C) III 5,153 Everglades West Coast Basin Group All of Basin IX and Basin V Small portion of Basin I (eastsoutheast section of basin) Approximately 1/3 of Basin VIII (north portion) low dissolved oxygen (DO) total nitrogen (TN) TMDL of TN = 0.74 mg/l Requirement: 29 percent reduction of TN This TMDL does not have an associated BMAP o Retrofit Standards Naples Bay Coastal, WBID 3278R4 II 9,581 Everglades West Coast Basin Group N/A Iron, Copper N/A Development of Naples Bay 2-year TMDL is still in progress. N/A Page 32

33 LOS - Water Quality I. Water Quality LOS 2. Existing requirements for pollution abatement i. New Construction Standards ii. 1. The current water quality design criteria LOS requires a project-specific BMP implementation to meet a presumed pollutant removal of 85 percent Total Suspended Solids (TSS), Total Nitrogen (TN), and Total Phosphorus (TP). Retrofit Standards 1. Developments should provide reasonable assurances that their proposed stormwater quality retrofit will provide additional water quality treatment such that there is a net reduction of the stormwater pollutant loading into receiving waters i. addition of treatment capacity to an existing stormwater management system ii. iii. adding treatment or attenuation capability to an existing developed area removing pollutants generated by, or resulting from, previous stormwater discharges Page 33

34 LOS - Water Quality I. Water Quality LOS 1. Summary of past recommendations Table 6.1. Summary of LOS Criteria Requirements Agency Water Quality Requirements City of Naples (Existing Comprehensive Plan 1996) a City of Naples (Existing Comprehensive Plan Updated December 3, 2013) b SFWMD (Environmental Resource Permit Applicant's Handbook Volume II) c Wet Detention: 1st. 1" or 2.5" X % Imp. Dry Detention: Wet Det. X 75%, 1" Min. Retention: Wet Det. X 50%, 1" Min. Wet Detention: Best Management Practices (refer to Comprehensive Plan section Public Facilities and Water Resources Element Policy 1-11) Dry Detention: 1.25 Minimum Retention: 0.5 Minimum Wet Detention: 1st 1" or 2.5" X % Impervious, whichever is greater Dry Detention: Wet Detention X 75%, 1" Minimum Retention: Wet Detention X 50%, 1" Minimum Page 34

35 Water Quality and Ecology Preliminary Recommendations Continue Implementing BMPs and Low Impact Design Consider a RAP for Naples Bay Intergovernmental Coordination with all stakeholders for all regional water bodies (aka. Naples Bay) Support other government entities that are taking an active role in managing stormwater (aka. Collier County master plan and stormwater utility Encourage agencies to operate weirs to allow for recharge into the aquifer instead of discharging to the Gordon River and Naples Bay Page 35

36 Regulatory and Development Code Review Key purpose to review the City land development codes, ordinances, stormwater utility codes and policies related to stormwater management; identify inconsistencies and gaps; and provide recommendations to enhance long term water quality and stormwater management. City Codes and Ordinances The National Flood Insurance Program (NFIP) Community Rating System (CRS) for the City The City s National Pollutant Discharge Elimination System (NPDES) Phase II Permit/Municipal Separate Storm Sewer (MS4) Page 36

37 Regulatory and Development Code Review Recommendations Develop and implement code changes that assist the City to: Obtain a better Community Rating from the National Flood Insurance Program To be in a better position for future flood mapping, NFIP reform, and protection from future flood events (climate adaptation) Page 37

38 Climate Adaptation How does sea level (SLR) relate to stormwater management? Sea Level Rise Projections Existing and Potential Future Water Levels Storm Surge and SLR Maps Summary of SLR Impacts to Stormwater System Components Evaluate Resiliency Design Standards Discussion of stormwater management practices Key Vulnerabilities and Potential Adaptation Strategies Page 38

39 Climate Adaptation - Trends Page 39

40 Climate Adaptation Relative Sea Level Rise Projections Page 40

41 Climate Adaptation Projections (Inundation for MHHW+3 ft) Page 41

42 Climate Adaptation - Recommendations Consider preparing a Climate Adaptation Plan that would look into vulnerabilities and provide specific adaptation strategies, physical strategies, informational strategies, and governance strategies for adaption to climate change events Consider retrofitting outfalls to include tidal valves to prevent water from backing into the stormwater management system Page 42

43 Best Management Practice (BMP) Review Low Impact Development (LID) devices are specific BMPs intended to address stormwater management using natural processes Goals and benefits of LID BMPs include improving water quality, attenuating flows, recharging groundwater, reducing potable water consumption, habitat restoration, improving aesthetics, and potentially a cost reduction in community infrastructure. Page 43

44 Best Management Practice (BMP) Review Page 44

45 Best Management Practice (BMP) Review Current BMPs are encouraged and are currently used as credits. BMPs include: Common swale Home Roof Drains Connect Directly to Swales or Exfiltration Pervious Driveway Driveway Trench Drain Rain Gardens Pool and Deck Self-Containment Native Landscaping the does not require fertilizers/pesticides Rain Barrels Preliminary Recommendations The stormwater management manual should be expanded to show BMPs that are desirable and recommend design standards Page 45

46 Operational Strategies Stormwater Infrastructure Outfalls, Manholes, Pipes, Lakes, Pumps, Streets, and Filter Marsh Stormwater Maintenance Maintenance Activities Operations Equipment Employees Natural Resources Operations Page 46

47 Operational Strategies Preliminary Recommendations Initial Review suggests that more staffing for operations activities may be needed, particularly in future years. Further evaluation is needed and will be included in the final draft Page 47

48 Capital Improvement Program Evaluation of Past 10-Years 9 Water Quality Projects 7 completed 77 CIP Projects 44 completed Proposed Projects Basin Projects basin studies, site specific capacity studies, pipe upsizing, construction of swales, construction of outfalls, public education, concrete flumes, and swale reclamation Lake Management Projects 12 projects identified in last plan, 4 completed Water Quality Projects City Identified Projects Page 48

49 Capital Improvement Program Probable Cost Estimates (Provide in Final Draft) Ranking Projects (Provide in Final Draft) Proposed Capital Improvement Plan Page 49

50 Capital Improvement Program Preliminary Recommendations Implement and finance the proposed capital improvement program determined at the end of this planning process Update the current Lake Maintenance Plan Page 50

51 Funding Rate Comparison/Evaluation Three comparable FL communities selected Significant Similarities Dealing with Sea Level Rise Coastal with Population Swings No SW Impact Fees Monthly Fee Basis Significant Differences Fee Calculation ERU/ARU Calculation Method for determining Impervious Area Communities City of Naples City of Venice City of Jacksonville Beach City of Fort Walton Beach Page 51

52 Funding Strategy Completed six (6) funding strategies in the past year Typically completed at 90% stage Projects are evaluated at the element level to identify the maximum number of opportunities Anticipate at least fifteen (15) potential funding sources and likely more Funding sources provided are based on a cursory review but not matched to specific projects at the 60% stage Page 52

53 Stormwater & Natural Resources Divisions Review Division Evaluations Goals Missions Objectives Budgets Findings Looking for overlapping duties Evaluating divisions duties Page 53

54 Stormwater & Natural Resources Divisions Review Preliminary Recommendations Due to the increase in regulation, aging infrastructure, level of service, retrofitting existing stormwater facilities, and increase in stormwater infrastructure that deals with water quantity and quality, increased staff may be needed to maintain and monitor and operate stormwater infrastructure into the future. Some additional responsibilities may need to be outsourced after further analysis is completed on the budget and future capital improvements and operation and maintenance activities. For instance, additional water quality monitoring may be outsourced. Due to the City of Naples being a stakeholder in several environmentally sensitive areas, the Natural Resources division will need to take a more active role in securing the City s interest in regional activities. Page 54

55 Public Involvement Three Opportunities were given to the public to be involved in the planning process. Monday, January 23, 2017 Wednesday, February 22, 2017 Survey Monkey o Uploaded on City website February 22, 2017 thru July 11, 2017 o ed to homeowners associations and City Council on March 15, 2017 Page 55

56 Survey Results Concern with roadway flooding and recovery time of the flood events Concern with water quality issues in both regional and local waterbodies. Also, there is a stronger general interest in improving/restoring Naples & Moorings Bay and Gulf of Mexico/Naples Beaches over other water bodies (such as lakes). There is concern about sea level rise and participants would like to see the City adapting infrastructure for these changes. There is generally a belief that there is an adequate level of operation and maintenance of the stormwater management system. In addition, the information gathered indicates that the City s stormwater drainage system adequately moves stormwater off streets in a reasonable amount of time. Since the results are close, this question is hard to determine the public s opinion concerning the drainage system during the wet-season. Page 56

57 Survey Results (continued) The public believes that there is not enough regulation and that they would like to see more regulation in water quality. The public is content with its current stormwater utility fee. The public preferred curbing with underground storage and rain gardens, bioswales, floating vegetation and low impact design. As to preference on the function of a project, the public preferred water quality by two votes over projects that address flooding and the environment. Lastly, when ranking in priority order the stormwater projects/programs, the public felt it was more important to coordinate with Collier County, the Big Cypress Basin, and the Florida Department of Environmental Protection first, and then, stormwater lake and beach restoration. Page 57

58 Survey Results (continued) Summary of Priorities Select 4 Components that are the Most Important to You Water Quantity-Flooding and Recovery Regulation Water Quality and Ecology Capital Improvements Workshop Survey Climate Adaptation Operation and Maintenance Funding Page 58

59 Next Steps 90% Deliverable Address 60% Comments Complete remaining items 100% Deliverable Address 90% Comments Council Workshop Page 59

60 Thank You September 6, 2017