Integrated Analysis of Storm Tidal Surge, Sea Level Rise, Precipitation and Low Impact Development for Flood Hazard Assessment in a Coastal Urban Watershed 2016 FLORIDA FLOODPLAIN MANAGERS ASSOCIATION (FFMA) CONFERENCE MARCH 30 TH,2016 PRESENTERS: JUSTIN JOYCE, MASTERS STUDENT, DEPT OF CIVIL, ENVIRONMENTAL, AND CONSTRUCTION ENGINEERING, UNIVERSITY OF CENTRAL FLORIDA NI-BIN CHANG, PH.D, P.E., DEPT OF CIVIL, ENVIRONMENTAL, AND CONSTRUCTION ENGINEERING, UNIVERSITY OF CENTRAL FLORIDA RAHIM HARJI, P.E., PINELLAS COUNTY THOMAS RUPPERT, ESQ, FLORIDA SEA GRANT PROGRAM

Introduction  Purpose of Analysis  Evaluating the results of various scenarios of SLR, storm-tide, and rainfall  Drivers for Analysis  Senate Bill 1094  Pinellas County  Results

Background: Risk  Coastal Hazards  Cyclonic storms (Storm surge/storm tide)  High Tide  Rainfall runoff  Vulnerability  Site Characterization  Infrastructure system  Exposure  Flood hazard mapping  Adaptive Capacity

Infrastructure Resilience to Flood Hazards  Resilience: Ability of infrastructure systems to absorb disturbance and bounce back after a disturbance  Reduced vulnerability  Greater adaptive capacity

Case Study: Cross Bayou Watershed  Sensitivity to coastal flooding hazards  County’s efforts to implement improved stormwater management within the watershed  County’s desire to evaluate long-term impacts of SLR and climate change

Case Study: Cross Bayou Watershed

Vulnerable Areas of the Cross Bayou Watershed. “Highpoint” residential area(top right) “Mariners Cove residential area (bottom right).

Hazards  Current:  Stormwater Runoff  High tide events (Cross Bayou Canal)  Future:  Tropical cyclones  Storm surge/storm tide  Sea Level Rise Source: National Geographic (top image). NOAA National Hurricane Center (bottom image )

Hazards: Sea Level Rise Source: Tampa Bay Climate Science Advisory Panel

Hazards: Tropical Cyclone TrackTime Period IntensityLandfall Location Direction of Approach RMW near landfall (km) 1 October 2030 Cat. 5 Indian Rocks Beach, FL SW-NE35 2 October 2030 Cat. 5 Tarpon Springs, FL S-NE35 3 October 2030 Cat. 5 Tallahassee, FL SE-NW35

Exposure: Flood Hazard Mapping

Hazards: Storm Events Storm Event ClassificationPeriod Small Storm Event Historical Record Median Storm Event Large Storm Event Small Storm Event+SLR Future Period 2030 Median Storm Event+SLR Large Storm Event+SLR

Storm Event Classification Date Frequency of Rainfall Data Frequency of Tidal Data Period Small Storm EventJuly minHourly Historical Record Median Storm Event Feb 1-4, minHourly Large Storm Event July 10-13, minHourly Small Storm EventAug 4-6, minHourly2030 Median Storm Event Dec 3-5, minHourly Large Storm EventOct 12-14, minHourly

Adaptive Capacity and Drainage System Resilience  Low Impact Development (LID) implementation  Decrease runoff  Decrease stress to drainage system

LID Siting & Choice  Drainage Area/Outfalls  Soil  Hydrologic soil grouping  Groundwater Table  Land Use  Local codes/standards  Stormwater manuals

LID Implementation Simulation TypeDescriptionLocation Existing  No LID implementation Not applicable LID Alternative 1  Pervious pavement only  High Point Elementary School  Pinellas County Jail complex parking lots LID Alternative 2  Pervious pavement  Green Roof  Swales  High Point (green roof, pavement and swales)  areas surrounding Pinellas County Jail (pavement only) LID Alternative 3  Pervious Pavement (w/ underground storage)  Green Roof  Dry Detention pond  Swales  High Point (green roof, pavement, swales and detention pond)  Areas surrounding Pinellas County Jail (pavement + storage)

Proposed LID Sites Site #Site LocationProposed LIDLID Sizing 1 High Point Elementary School 58 th St N Green Roof & Pervious Pavement (parking lot) 1.6 acres (green roof) 2 acres (pervious pavement) 2High Density Residential AreasBioswales0.35 acres 3South of 150 th Ave (High Point)Detention Pond2.8 acres 4Pinellas County Jail-Parking LotsPervious Pavement9.3 acres

Quantitative Resilience Metrics Interconnected Channel & Pond Routing (ICPR) software v.4 (Streamline Technologies, Inc., 2015) Graphic of ICPR Cross Bayou Watershed Model

Points of Interest

Resilience Metrics- Peak Outflow Reduction

Summary  Resilience tied to flood risk assessment  Quantitative metrics can be useful  Resilience must cover multiple aspects  Engineering  Social  Planning  Policy

Summary  Importance of groundwater  LID implentation  Sea level rise concerns  Complexity of Florida rainfall  Convective vs. frontal rain  Future Projections

References Chang, N., 2010: Hydrological Connections between Low-Impact Development, Watershed Best Management Practices, and Sustainable Development. J. Hydrol. Eng. 15, SPECIAL ISSUE: Low Impact Development, Sustainability Science, and Hydrological Cycle, 384–385. Egbert, G. D., Bennett, A. F., and Foreman, M.G.G.,1994: TOPEX/POSEIDON tides estimated using a global inverse model. Journal of Geophysical Research 99 (C12): Holling, C.S., 1973: Resilience and stability of ecological systems. Annual review of ecology and systematics, pp. 1– 23 Jones Edmunds and Associates, Inc., 2013: Floodplain Analysis, Cross Bayou Watershed Management Plan. Pinellas County Board of County Commissioners and Southwest Florida Water Management District. Kivett, J. R., 2015: Impacts of Sea Level Rise on District Operations. Water Resources Advisory Commission. South Florida Water Management District. February 5, Omer. M., 2013: The resilience of networked infrastructure systems. World Scientific. Pinellas County Planning Department, 2012: Pinellas County Comprehensive Plan. Accessed July [Available online at Stream Technologies, Inc., 2015: An Integrated Surface Water-Groundwater Model of the Cross Bayou Watershed. Wilby, R.L, Dawson, C.W., Barrow, E.M., 2002: SDSM—a decision support tool for the assessment of regional climate change impacts Environ. Model Softw., 17 (2): 145–157

Questions?