Broward County, Florida 100 -Year Flood Elevation Map and - - PowerPoint PPT Presentation

Broward County, Florida 100 -Year Flood Elevation Map and Associated Modeling

Bid No. R2114367P1 September 27, 2017

Meet the AECOM Team

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Key Team – Roles and Responsibilities

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Key Benefit: AECOM has assembled a proven technical team capable of adding value with innovations.

Pradeep Nagarajan, PE Project Manager Maria Loinaz, PhD, PE Modeling Technical Lead Pamela Adams Stakeholder Coordination Lead Davicka Thompson Public Education & Information Lead Fernando Miralles-Wilhelm, PhD, PE, BCEE, DWRE/PMP Climate Change and Sea Level Rise Technical Lead

Team Qualifications

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• Developers of current MIKE SHE / MIKE 11 model

for the 100-year Flood Elevation Map

• Knowledge of all major drainage basins in the

County

• Prepared 100-year Flood Elevation Maps for:
• Palm Beach County, FL
• Brevard County, FL
• St. Lucie County, FL
• Indian River County, FL
• Clay County, FL

Key Benefit: Tools and team to perform this work.

AECOM Relevant Projects

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Digital Flood Insurance Rate Map and Flood Insurance Study Report, FEMA Region IV Br Broward County, , FL FL

Benefit: Knowledge Transfer

• Team has all internal tools used

to develop County Digital Flood Insurance Rate Maps

• Team understands sensitivities
• f the model and how they react

to events

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Benefits Relevant Projects Bring

Kissimmee Basin Modeling and Operations Study So South Florida W a Wat ater M Man anagement Di Distric ict

Benefit: Continuity

• Team that developed the KBMOS

model also worked on the Broward County’s MIKE SHE / MIKE 11 model, will also work on the 100-year Flood Model

• Original tools and routines

Key Benefit: Ability to integrate and deliver modeling, improve CRS rating and stakeholder involvement.

Relevant Projects – Community Rating System

Sarasota County Watershed Model Maintenance and GIS Update – Lemon Bay Model Saras asota a County, F , FL

Benefit: Proven Approach

• National Flood Insurance Program and the

Community Rating System Program

• Floodplain Management Plan
• Model calibration utilizing data from major storm events
• Hydrologic and Hydraulic modeling

National Flood Insurance Program / Community Rating System / Local Mitigation Strategy Assistance

Sar aras asota County, F , FL

Benefit: Reduced Flood Insurance Rates

• National Flood Insurance Program and the Community

Rating System Program

• Development of Community Involvement Plan
• Stormwater Regulations
• Qualified for Flood Mitigation Funds

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Project Understanding and Approach

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Project Understanding

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• Consistency performed in 2014

model update and precursor models(NADA, SADA, CADA)

• Thorough understanding of the

MIKE SHE/MIKE 11 model (complexities; constraints; and performance)

• Knowledge and lessons learned

during the previous updates Update Broward County 100-year Flood Elevation Map through:

• Refinement of the latest County-

wide integrated MIKE SHE/MIKE 11 H&H Model that includes:

• Future climatic conditions
• Sea Level Rise

The Main Objective The Team Brings

Key Benefit: Each update is unique and adaptive.

Overall Innovative Project Approach

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Public lic Engagem emen ent an and Stakeh eholder er Involvem emen ent

Key Benefit: Proactive, collaborative stakeholder approach to identify and address concerns.

Development / Update of Existing Conditions FEMA MIKE SHE/MIKE 11 Model

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Existing Conditions Model Calibration \ Validation \ and Simulation

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Development / Update of Future Conditions FEMA MIKE SHE/MIKE 11 Model

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Development of Future Conditions 100-Year Floodplain Delineation

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Public Engagement Approach

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• Purpose
• Introduce project and highlight benefits
• Communicate early and often
• Listen to stakeholders
• Address outstanding concerns
• County Benefits
• Feedback from stakeholders early in the

development process

• Public education
• Community support of the project

Stakeholder workshop for Kissimmee Basin project

Key Benefit: Inform and garner stakeholder support.

–Residents –Civic and Business Organizations –Government Partners –Academia/Schools –Healthcare Systems –Environmental Advocates –Utilities and Regulators (e.g., SFWMD, FPL) –Elected Officials

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Public Engagement and Key Stakeholders

Key Stakeholders

Educate and inform stakeholders on the importance of developing and delivering solutions to efficiently address flooding concerns; and work collectively to improve the Community Rating System.

• Stakeholder meetings
• Traditional media outreach
• Social media
• Interactive webpage
• Short educational video
• Mobile applications
• Brochures / newsletters / infographics
• Utility bill inserts
• Planning model simulations

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Engagement Tools and Activities

Key Benefit: Utilize as many platforms as are available and appropriate to convey messages efficiently.

Project Approach – Data Collection Activities

Development / Update of Existing FEMA MIKE SHE/MIKE 11 Model

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Data Collection and Review – Topo, Land Use and H&H Info/Reports Field Reconnaissance – Confirm the existence or non-existence of data Survey and Mapping (WSM) Sub-Consultant: Whidden

Project Approach – Update of Existing Conditions Model

Update of MIKE SHE Model

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Development of Rainfall Events for Existing Conditions

• Existing conditions: for calibration and

validation

• Review historical rainfall records (Past

10 years)

• Identify storms with maximum intensity
• ver 3-day period, possibly Hurricane

IRMA

• Evaluate rainfall patterns
• Convert to the precipitation rate file in

MIKE SHE format

Project Approach – Update of Existing Conditions Model

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• Update Model Software Version to 2017
• Check against old results
• Possibly re-conceptualize representation of rainfall-

runoff processes based on new options in the code.

• Update Time Varying Data to Simulation Period

(based on the Selected Calibrated Event)

• Rainfall
• Reference evapotranspiration
• Measured stages and flow (calibration and boundary

conditions)

• Structure operations
• Update Input Data with the Latest Available

Information

• Topography with Latest LiDAR
• Survey Information: canal cross-sections and

structures

• Land use (if applicable)

Project Approach – Existing Conditions Model Calibration/Validation

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Quality Checks

• Sub-basin Stage – Storage: LiDAR versus model topography input file
• Remove numerical instabilities
• Mass balance conservation in surface water - groundwater exchanges

Modify Parameters for Calibration

• Horizontal and vertical hydraulic conductivity (Kh and Kv)
• Surface water – groundwater exchange features (flood codes, leakage

coefficients)

• Surface and sub-surface runoff parameters (drainage, paved- areas)
• Manning’s n (overland flow and MIKE 11 cross sections)

Key Benefit: County gains future conditions model with climate change and sea level rise factors.

Project Approach – Future Conditions Model Development

Model Development for Future Conditions (2060 and 2100)

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• Updated and approved 10-yr, 25-yr, 50-yr, 100-yr and 500-yr design

storm events for Future Conditions (2060 and 2100)

• Inclusion of sea level rise from Compact 2015
• Climate change adaptation
• Key challenges:
• Tidal and groundwater boundary – Inclusion of sea level rise
• Non-Stationarity of IDF Curves – Future Climate Conditions

Addressing Key Challenges – Inclusion of SLR

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• Tidal Boundaries
• SFWMD – future tidal

conditions development

• Zone A Coastal modeling
• Antecedent (Initial)

Conditions and Groundwater Boundaries

• USGS MODFLOW models

Addressing Key Challenges – Future Climate Conditions

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Acknowledging Non-Stationarity –Current IDF curves assumes stationarity and statistics are constant (independent of time) –Increasing/decreasing trends already observed due to lower frequency climate variability (e.g., El Nino Southern Oscillation or Atlantic Multi-decadal Oscillation) –Stationary assumptions potentially result in lower IDF curves (USACE 2016)

Key Benefit: Automated post- processing tool to develop future IDF curves and visualize spatial variation in precipitation.

AECOM Toolbox to streamline analysis and development

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AECOM Forecasting Local Extremes (FLEx) Tool

Streamline Download and Analysis of Historical Station Data Large Downscaled GCM Datasets Flexible Compute Range of Anytime Epoch Different Statistical Tech. e.g., 95th perc. – 5 day max Precipitation Statistics Compute Generate IDF Curves Time Horizon Different RCP Scenarios Any GCMs GIS Toolbox Analyze Changes in Spacial Variation

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Post-process and Visualize Spacial Variation in Precipitation

Unique Data Processing Tools

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100-Year Flood Elevation Map and Associated Modeling

IDF, Historical data IDF, Under climate change Reports & Output Set Up Home

Home

Future IDF (FLEx)

Rainfall Conversion Terrain Processing Groundwater Conversion Wise-Floodplain

Automate the processing of rainfall data for any design event to different rainfall patterns to be utilized in MIKE SHE/MIKE 11 model Automatically merge the changes with recent aerial photography, land cover GIS feature classes, as-built and data from survey to create a single topography file from the existing LiDAR data This specific utility is to easily convert the updated MODFLOW output files to MIKE SHE/MIKE 11 input files to allow for future updates based on changes to the groundwater model or sea level rise projections. The merging tool is to integrate the results from the updated MIKE SHE/MIKE 11 model and Coastal Zone A Model by comparing the elevation results within a single grid, optimize the results and finally develop a single grid file that will eventually be used to develop the 100-year Flood Elevation Map

Unique Data Processing Tools

Community Rating System (CRS)

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Broward’s Community Rating System Score = 7

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Goals Elements Activities

Reduce flood damages to insurable property Strengthen and support the insurance aspects of the NFIP Encourage a comprehensive approach to floodplain management Public Information Activities (Under 300)

• Elevation certificates
• Map information service
• Outreach projects
• Hazard disclosure

Mapping and Regulation Activities (Under 400)

• Flood hazard mapping
• Higher regulatory

standards

• Flood data maintenance
• Stormwater management

Prepare and deliver presentations Hazard Disclosure Category Flood Hazard Mapping Higher Regulatory Standards Flood Data Maintenance and Stormwater Management Activity

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When the County partners with Our T eam, you will:

• Access to modeling resources
• Proven QA/QC program
• ISO 9001 certification for more than 10 years
• Improve your Community Rating System
• Major benefit:
• Future Planning
• Infrastructure Investments
• Development Requirements