New_Smyrna_Beach_-_Stormwater_Master_Plan_Phase_2_-_Background_and_Scope_of_Work_(01_17_25).docx

City of New Smyrna Beach Stormwater Master Plan (SMP) Phase II Background The City of New Smyrna Beach (NSB) watershed is approximately 41 square-miles and includes major watercourses such as Spruce Creek, Turnbull Canal, and Halifax River/Indian River within its boundaries. The basin areas east of Interstate 95 are mostly developed with older neighborhoods constructed prior to SJRWMD permit regulations. The newer developments are located on west side of Interstate 95, including Venetian Bay master planned community. State Road 44 and U.S. Highway 1 bisect the city limits and serves as a major hurricane evacuation route for the residents on beach side.

The city last completed a Stormwater Master Plan in December 1998. Since the 1990’s the city’s population has grown from about 16,500 to over 33,000 residents today. In September 2022, Hurricane Ian impacted the city and caused over 1,000 homes to be flooded. Then in October 2024, Hurricane Milton caused major arterial, collector, and local roads flooding with about 30 homes structural flooding. As a result, the mitigation of flood risks, protecting properties from future flooding, and upgrading the city stormwater infrastructure are priorities for the City Commission, NSB residents, and local businesses.

In April 2024, the city initiated the Stormwater Master Plan Phase I work. This phase includes data collection and review of existing ERP permits, incorporating latest state-wide LiDAR data and aerial imagery, investigating known flooding areas and field reconnaissance, assembly and evaluation of the watershed boundaries, water quantity and quality assessments, and ArcGIS mapping of drainage infrastructure using the Water Management District GWIS database file format. Phase I is expected to be completed in April 2025 by the City of New Smyrna Beach Engineering Division.

On November 19, 2024, Volusia County BOCC approved a Transform386 grant for the city-wide Stormwater Master Plan Phase II scope of work. The SMP Phase II work will be project managed by Volusia County staff and will commence immediately after the completion of Phase I. The Phase II scope of work consists of the following major tasks:

1. Stormwater Model Development - Existing Conditions and Proposed Conditions ICPR Version 4.0 (Expert) 1D Models with supporting data

2. Level of Service (LOS) improvement alternatives analysis and cost estimates

3. Floodplain mapping and FEMA permitting

4. Public outreach meetings and presentations

5. Conceptual design plans for the alternatives

6. Final deliverable Stormwater Master Plan Report

SMP Scope of Services – Phase II

Task 1 – Project Initiation

One (1) week of the kick-off meeting, the CONSULTANT shall prepare meeting minutes and distribute them to COUNTY staff for review and comment. A project estimate schedule shall be prepared and distributed at the kick-off meeting.

Task 2 – Stormwater Model Development

The required scope of services under this task, shall include but not be limited to:

Subtask 2.1 Stormwater Network Feature Database The CONSULTANT shall follow the Geographic Watershed Information System Database Design Document Version 2.1 (GWIS 2.1) published by the Southwest Florida Water Management District (SWFWMD) for with the Interconnected Channel and Pond Routing software called “StormWise” Version 4.08.03 or latest (formerly known as ICPR 4) by Streamline Technologies.

Subtask 2.2 Preliminary Model Schematic & Hyrdological Unit (Sub-basin) Delineation The CONSULTANT shall delineate the hydrological units (sub-basins) using GIS tools and available topographic information. The CONSULTANT shall develop the model schematic for the SMP using naming conventions approved by the COUNTY and CITY.

Subtask 2.3 Model Parameterization The CONSULTANT shall incorporate the parameterized model features into GWIS

2.1 identified below:

· CN Look-up table

· Selected design storm events

· Time of Concentration (Tc)

· Node Storage

· Initial water level conditions in the system to be modeled

· System outfall boundary conditions

· Channel representations

· Bridge representations

· Pipe representations

· Weir representations

· Drop structures

Subtask 2.4 Model Setup and Design Storm Simulations The CONSULTANT shall transfer model parameters from the GWIS 2.1 geodatabase into the StormWise model framework. The CONSULTANT shall review preliminary model results for a single design storm event for numeric stability (continuity error of less than 5 percent). The CONSULTANT shall simulate the Mean Annual, 5-year, 10-year, 25-year, 50-year, and 100-year storm events based on the Natural Resources Conservation Service (NRCS) Type II (Florida Modified) rainfall distribution of a 24-hour duration. In addition, the CONSULTANT shall simulate the 25-year storm based on SJRWMD 96-hour distribution and City of New Smyrna Beach 100-year 72-hour storm event to account for either closed basin / hydrological units that discharge to landlocked lakes and water bodies. The CONSULTANT shall confirm with the COUNTY and CITY, the rainfall volume associated with each design storm event in advance of the stormwater model simulations.

Note: The ICPR analyses for the Stormwater Master Plan Phase II shall be performed using the “one- dimensional” method. Such that Drainage Areas, Time of Concentration, and Curve Numbers must be determined by the engineer and shown in the ICPR pre and post condition models.

Task 3 – Level of Service (LOS) Improvement Alternatives Analysis

Subtask 3.1 Alternatives Analysis and Project Ranking The CONSULTANT shall identify feasible stormwater Capital Improvement Projects (CIP) to meet the COUNTY and CITY’s selected LOS for the structures within the model (within the SMP) that are predicted not to meet the assigned LOS. The CONSULTANT shall document each alternative with a description of the proposed project and each project’s advantages and disadvantages. The CONSULTANT shall rank all the alternatives using a ranking approach considering the following factors:

· Flood control benefit and Level-of-Service (LOS) improvements

· Permitting requirements

· Water quality and environmental benefits and compliance with NPDES and TMDL requirements

· Engineer’s opinion of probable design and engineering costs

· Engineer’s opinion of probable right-of-way / property acquisition cost (if applicable)

· Engineer’s opinion of probable construction cost

· Operation and Maintenance (O&M) needs long-term

· Public acceptance for alternative

For those alternatives that provide a water quality benefit, the CONSULTANT shall perform a desktop analysis using the BMP TRAINS tool to estimate the pollutant load reduction for total nitrogen (TN) and total phosphorous (TP). A minimum of three (3) alternatives that provide a water quality benefit shall be evaluated.

All proposed alternatives must be permitted without opposition from the St. John’s River Water Management District (SJRWMD). CONSULTANT must coordinate with SJRWMD staff on permitting requirements prior to finalizing the alternatives.

The CONSULTANT shall provide cost estimates at the present worth dollar value for each identified alternative. The cost estimates shall be based on the conceptual layout and shall be subject to change pending more detailed designs that are beyond the scope of this study. The stormwater improvement alternatives shall focus on identified flooding problem areas. The CONSULTANT also shall develop GIS layouts for each conceptual alternative.

Task 4 – Floodplain Mapping and FEMA Permitting

Subtask 4.1 – Floodplain Delineation The CONSULTANT shall delineate the floodplain based on available digital topographic information and modeled predicted peak stages for the 100-year storm event. Floodplain areas will be delineated based on the greater stage indicated from the 100-year, 24-hour stage event or higher storm intensity event if required by FEMA. The floodplain delineation digital shape features shall be included in the GWIS 2.1 database. The CONSULTANT also shall compare the preliminary floodplain with the effective FEMA flood hazard zone and document in the study. For those areas that do not have recent detailed one-foot contour information, the extent of the floodplain shall be approximated using FEMA 265 (Zone A Manual) guidelines.

Subtask 4.2 – FEMA Letter of Map Revision (LOMR) Package The CONSULTANT shall compile all the necessary documents and data necessary for submitting a Letter of Map Revision (LOMR) package to FEMA. This task shall focus on establishing base flood elevations for areas currently designated as Zone A and providing updated based flood elevation data for existing Zone AE areas where applicable. This task shall include the preparation and submittal to FEMA of the following:

· Complete application MT-2 forms

· LOMR submittal report that incorporates project documentation, model data, figures, exhibits prepared as part of the other aforementioned tasks in the proposal

· Annotated FIRM map for areas of requested map change

· Technical Support Data Notebook (TSDN) supporting documentation. The TSDN directory shall conform to current FEMA guidelines. The complete TSDN directory structure shall be developed, however, only those directories relevant to this study shall be populated.

· Internal Senior and Peer review QA/QC

· LOMR Package Production, Electronic Deliverables and Delivery

The CONSULTANT shall be responsible to address ALL FEMA requests for information (RAI) required to obtain FEMA’s approval of the LOMR.

Task 5 – Public Meetings

Subtask 5.1 – Meetings with County and/or City Commissioners The CONSULTANT shall attend two County or City Commission meetings that are coordinated by the COUNTY and/or CITY. The first meeting shall take place following the completion of the draft report. The second meeting shall provide a brief presentation of the study results with consideration of the comments received during the public meetings and from the County and/or City Commission on the draft report. The presentations shall be performed by the CONSULTANT and shall be prepared utilizing Microsoft Powerpoint and be limited to a maximum of 25 slides. The COUNTY and/or CITY shall schedule the presentation with the Commission.

Subtask 5.2 – Meeting with Citizen Groups The CONSULTANT shall attend and present at two (2) public meetings. The CONSULTANT shall prepare the necessary presentation materials for each meeting as well as respond to questions and solicit input regarding the proposed stormwater plans for the SMP. The COUNTY and/or CITY shall identify and secure the meeting venue.

Task 6 – Report

Subtask 6.1 – Stormwater Master Plan Final Flood Control Study Reports The CONSULTANT shall prepare the SMP Study Draft Reports for COUNTY and CITY review summarizing the data and results of Task 1 through Task 6 in digital (pdf) format. The CONSULTANT shall also provide, in digital format, the draft GWIS 2.1 geodatabase(s) of collected data used in the study and the StormWise (ICPR 4) stormwater model input. The CONSULTANT shall meet with the COUNTY and CITY to discuss the results of the reports and incorporate the COUNTY and CITY’s comments into the final reports. The CONSULTANT shall also provide meeting summary notes from both the County and/or City Commission and public meetings as an appendix to the draft and final reports. The CONSULTANT shall print and assemble the SMP report.

Control Study Final Reports into five hard copy with binders. The report shall include, but not be limited to, the following report section topics:

· Introduction

· Data Collection and Model Parameterization

· Model Development, Results, and LOS Evaluation Narrative

· Alternatives Analysis and Prioritization Narrative

· Summary and Conclusions Narrative Task 7 – Project Quality Management / Meetings Activities performed under this task consist of those general functions required to maintain the project schedule to ensure the quality of work included in this scope is consistent with COUNTY and/or CITY standards. Specific activities included are identified below:

Subtask 7.1 – Project Progress Meetings The CONSULTANT shall participate in three (3) project status review management meetings. These status meetings are intended for discussion regarding:

1) Results of data collection and survey needs

2) Results of stormwater model and LOS evaluation

3) Proposed alternatives, their advantages and disadvantages and their associated costs.

The CONSULTANT shall prepare meeting minutes following each progress meeting and provide them to the COUNTY and CITY within five (5) working days following the meeting.

The CONSULTANT shall coordinate and attend one (1) meeting with the SJRWMD to discuss the proposed alternatives.

Subtask 7.2 – Project Quality Management The CONSULTANT shall maintain an internal quality management system to review various milestone submittals.

Subtask 7.3 – Project Status Reports The CONSULTANT shall prepare and submit to the COUNTY a monthly written status report and invoice over the project’s duration. The CONSULTANT shall also provide bi-weekly e-mail updates.

Project Deliverables:

1) Five (5) signed and sealed (by a Professional Engineer registered in the State of Florida) of the SMP Study Final Report.

2) Digital Elevation Models (DEM) for the basin study where available.

3) GWIS 2.1 geodatabases containing:

· Hydrological units / sub-basins [ICPR_BASIN]

· Stormwater surface connectivity provided as the HydroNetwork [HYDREDGE and HYDROJUNCTION]

· Model Connectivity [ICPR_LINK and ICPR_NODE]

· Historical water levels [HISTORICAL_WATER_LEVELS]

· Land use map [GWID_LANDUSE]

· NRCS Soil Map [GWIS_SOIL]

· Curve Number Lookup Table [ICPR4_CURVE_NUMBER_ZONES]

· Delineated Floodplain [GWIS_FLOOD]

4) Support Data

· Documented flooding problems and complaints

· Topographic information (contours, break lines, spot grades, etc.)

· Basin boundary

· ERP’s incorporated into the basin model

· Data acquisition need locations

· Drainage System Classification for LOS analysis

· Model input / output files for the Mean Annual, 5-year,10-year, 25-year, 50-year, and 100-year, 24-hour events and the 25-year, 96-hour event (SJRWMD closed basin) and 100-year, 72-hour event (City of NSB LDR closed basin)

· Model input / output files for alternatives analysis

· Locations of final recommended alternatives

5) Meeting Attendance

· Kickoff meeting (one)

· Progress Meetings (three)

· SJRWMD Pre-Application meeting (one)

· County or City Commission Meetings (two)

· Public Meetings (two)