Miami-Dade County Technical Update Meeting South Florida Coastal Study. May 11, 2016

Transcription

1 Miami-Dade County Technical Update Meeting South Florida Coastal Study May 11, 2016

2 Welcome and Introductions FEMA Region IV Christina Lindemer Technical Lead Production and Technical Services (PTS) Contractor Chris Bender Coastal Engineer 2

3 Agenda Risk MAP Overview Coastal Project Overview Status and Update Questions and Answers 3

4 Risk MAP Program Overview Risk MAP Objective (Coastal) To provide updated flood hazard data for 100% of the populated U.S. coast 4

5 Risk MAP Project Timeline Coastal Modeling FIRM Production 5

6 South FL Coastal Study What It Is Not The new FEMA Coastal Study is NOT a Hurricane Evacuation Study and is not meant to replace your current Hurricane Evacuation Study. 6

7 Ongoing Coastal Studies 7

8 South FL Coastal Study Project Goals 8

9 Study methodology DEM and Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Validation Canal Sensitivity Questions? 9

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11 SWAN+ADCIRC Water levels + currents + waves Parallelized code Forcing Windspeed, barometric pressure Tides Riverine flow Output Water-surface elevation Velocity Wave height, peak period, mean period, direction Radiation stress 11

12 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal Sensitivity 12

13 Seamless Topographic and Bathymetric Data Surface (DEM) Development 13

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15 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal Sensitivity 15

16 Hurricane Model Mesh 16

17 SFL Mesh Grid Resolution Resolution down to 50 feet in some areas High population density leads to complex road networks to capture Extensive canal systems 17

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19 Node spacing set to accurately represent topography/bathymetry Applies feature arcs to represent elevated or depressed features (e.g., roads or channels) 19

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21 Bathymetric Mesh SFWMD Control Structures 21

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23 Miami-Dade County 23

24 SWAN+ADCIRC mesh - Miami-Dade County Elevation, Feet-NAVD 24

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29 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal Sensitivity 29

30 Land Classification Data Need large-coverage datasets to provide consistent and comprehensive land cover data NOAA, EPA, USGS work together to develop Coastal Change Analysis Program (C-CAP) data 25 categories of land cover emphasis given to more detailed, up-to-date wetland information than currently available in other national land cover products 30

31 Land Classification Data Class No. Land Cover % Land Class in Study Area 0 Background - 1 Unclassified - 2 High Intensity Developed Medium Intensity Developed Low Intensity Developed Open Spaces Developed Cultivated Land Pasture/Hay Grassland Deciduous Forest Evergreen Forest Mixed Forest Scrub/Shrub Palustrine Forested Wetland Palustrine Scrub/Shrub 4.4 Wetland 15 Palustrine Emergent Wetland Estuarine Forested Wetland Estuarine Scrub/Shrub 4.3 Wetland 18 Estuarine Emergent Wetland Unconsolidated Shore Bare Land Water Palustrine Aquatic Bed Estuarine Aquatic Bed

32 Land Classification Data Working to improve methods to quantify land cover effects on storm surge Team member UCF LIDAR-based assessment of vegetation Field-based measurement of vegetation features Provide sensitivity study for validation models 32

33 Land Classification Data Seagrass and hardbottom in Biscayne Bay and the keys Manning s n 33

34 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal Sensitivity 34

35 Site Reconnaissance Effort Field reconnaissance completed at 89 locations Sites categorized into five classes: 1. surge conveyance pathways and four classes of raised features; 2. other manmade embankments (roads, railroads, and bridge approaches); 3. flood protection and other hydraulic control structures; 4. natural topographic features (including dunes); 5. shoreline features (shoals, breakwaters, jetties, groins, beach nourishments) 35

36 Site Reconnaissance Effort Create Google Earth dataset to catalog locations, notes, and photos Apply this data during mesh refinement stage 36

37 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal Sensitivity 37

38 JPM - Reasonable method to statistically represent storm parameters consistent with local climatology Use a coarse ADCIRC mesh (60,000 nodes) to run large number of storms USACE method of Optimal Sampling minimizes number of storms represented in final storm suite while maintaining sufficient accuracy 38

39 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal sensitivity 39

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43 Digital Elevation Model (DEM) Mesh Development Land Cover Data Analysis Site Reconnaissance JPM-OS Storm Suite Selection Validation Canal Sensitivity 43

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45 Elevation, ft-navd 45

46 Elevation, ft-navd 46

47 FEMA coastal flood risk study of south Florida underway SWAN+ADCIRC model with 2.3 million nodes uses seamless bathy-topo DEM Land cover data, field reconnaissance data incorporated into model mesh development Current work JPM-OS production storm suite Validation Canal sensitivity 47

48 South FL Coastal Study Process Discovery Data Acquisition Coastal Engineering Analyses Floodplain Mapping Produce Preliminary Flood Insurance Rate Maps Post-Preliminary Processing 48

49 South FL Coastal Study Project Schedule

50 Basic Elements of a Coastal Flood Risk Study Base Flood Elevation (BFE) on FIRM includes 4 components: 1. Storm surge stillwater elevation (SWEL) Determined from 2. Amount of wave setup storm surge model 3. Wave height above storm surge (SWEL) elevation 4. Wave runup above storm surge elevation (where present) 50

51 South FL Coastal Study Floodplain Mapping 51

52 South FL Coastal Study Miami-Dade Scope of Work Shoreline Miles Estimated WHAFIS Transects Transects Per Mile Estimated Panels Communities 28 Effective transects shown 52

53 South FL Coastal Study Community Meetings Community Meetings Discovery Kick-Off Meeting Discovery Meeting Technical Update Meeting Storm Surge Analysis Update Meeting Flood Risk Review Meeting Resilience Meeting Preliminary DFIRM Community Coordination Meeting Public Open Houses 53

54 South FL Coastal Study Points of Contact Christina Lindemer Michael DelCharco, PE