Citrus, Hernando, and Pasco Coastal Hazard Analysis. Flood Risk Review Meeting Citrus, Hernando, and Pasco Counties, Florida December 14, 2017

Transcription

1 Citrus, Hernando, and Pasco Coastal Hazard Analysis Flood Risk Review Meeting Citrus, Hernando, and Pasco Counties, Florida December 14, 2017

2 Introductions Risk MAP Project Team FEMA Region IV RAMPP (study contractor) BakerAECOM (independent review support) Project Stakeholders Community CEOs Community FPAs Political Representatives Other State and Federal Agencies Public 2

3 Agenda for Today Introductions Risk MAP Program Overview Project Timeline Coastal Study Overview Work Session Review of work maps Answer questions 3

4 FEMA s Risk MAP Program Mapping Assessment Planning Regulatory Products: Flood Insurance Study (FIS) FIRM (Coastal re-mapping) New Non-Regulatory Products and Datasets Will deliver quality data that increase public awareness and lead to action that reduces risk to life and property 4

5 Why the Coastal Flood Risk Study Is Being Updated Flood risk changes over time Effective study based on outdated hurricane modeling and topographic data Ability to more accurately define risk and account for significant development in project area To gain a complete and current picture of coastal flood risks. This helps community: Plan for the risk Communicate the risk to your citizens Take action to reduce flood risk to lives and property Build smarter and safer 5

6 Why the Coastal Flood Risk Study Is Being Updated (Cont d) Current surge analysis is 30 to 40+ years old Surge updated using FEMA Coastal Flood Storm Surge Model in 1979 Surge study included climate data through 1977 Your risk is better defined through Updated elevation data (topographic data and aerial imagery) New climatological data based on recent storms Computing resources a lot has changed in 30 years! Updated coastal hazard methodologies/modeling Improvement in Geographic Information System (GIS) technologies to improve coastal mapping accuracy 6

7 Project Timeline for Citrus, Hernando and Pasco Discovery Meeting Jan 2013 Mesh Review Meeting Sept 2013 Storm Surge Analysis Update Meeting April 2016 Flood Risk Review Meeting TODAY! Open House / CCO Spring/Summer

8 Coastal Study Outreach Efforts Coastal Community Engagement Plan RIV Website: Outreach Factsheets Outreach Meetings: Initial Community Coordination Discovery Meeting Storm Surge Analysis Update Meeting Flood Risk Review Meeting Final CCO Meeting Open House Resilience Meeting 8

9 Basic Elements of a Coastal Flood Risk Study Base Flood Elevation (BFE) on FIRM includes four components: 1. Storm surge stillwater elevation (SWEL) Determined from 2. Amount of wave setup storm surge model 3. Wave height above storm surge elevation 4. Wave runup above storm surge elevation (where present) 9

10 Citrus County Effective vs. New Coastal Study Coastal Study Component Topographic data Effective Study (1984) New Study (2017) 1979 USGS 5 foot contour interval 2007 FDEM LiDAR SWELs 1979 Coastal Flooding Storm Surge Model Modeled transects Wave setup No Yes Wave runup No No LiMWA No Yes 2017 West Florida Storm Surge Study 10

11 Hernando County Effective vs. New Coastal Study Coastal Study Component Topographic data Effective Study (1984) New Study (2017) 1979 USGS 5 foot contour interval 2007 FDEM LiDAR SWELs 1979 Coastal Flooding Storm Surge Model Modeled transects Wave setup No Yes Wave runup No No LiMWA No Yes 2017 West Florida Storm Surge Study 11

12 Pasco County Effective vs. New Coastal Study Coastal Study Component Topographic data Effective Study (1981) New Study (2017) 1979 USGS 5 foot contour interval 2007 FDEM LiDAR SWELs 1979 Coastal Flooding Storm Surge Model Modeled transects Wave setup No Yes Wave runup No Yes LiMWA No Yes 2017 West Florida Storm Surge Study 12

13 Topographic and Bathymetric Data 13

14 Topographic and Bathymetric Data 14

15 Topographic and Bathymetric Data 15

16 Topographic and Bathymetric Data 16

17 Citrus County Transects 17

18 Hernando County Transects 18

19 Pasco County Transects 19

20 Wave Runup Runup modeled for beaches, bluffs, cliffs and coastal structures Methods: TAW CSHORE Runup2.0 20

21 Wave Runup How runup is mapped? SWEL SWEL+Runup Ground profile Profile view of Transect

22 Primary Frontal Dune (PFD) a continuous or nearly continuous mound or ridge of sand with relatively steep seaward and landward slopes immediately landward and adjacent to the beach and subject to erosion and overtopping from high tides and waves during major coastal storms NFIP regulations 22

23 Flood Zone Mapping 23

24 Mapping: Flood Hazard Zones Base Flood Elevation (BFE): The height in feet above a certain datum (in this case, NAVD 88) that flood waters have a 1 percent annual chance of reaching or exceeding in any given year Zone VE: Defined by wave heights of 3 feet or greater Zone AE: Defined by wave heights ranging from 0 to 3 feet Zone AO: Shallow flooding with average depths between 1 to 3 feet 24

25 Mapping: LiMWA Limit of Moderate Wave Action (LiMWA) Defines the inland limit of the area expected to receive wave action of 1.5-foot or greater CRS benefit for communities requiring VE Zone construction standards in areas defined by LiMWA 25

26 Workmap Symbology City of Dunedin, City of Clearwater 26

27 Work Session Review Work Maps Base Flood Elevations (BFEs) Flood Zone designations (VE vs AE) Limit of Moderate Wave Action (LiMWA) Answer questions Thank you for your participation! 27

28 Thank you We look forward to continuing to work with you to help Citrus, Hernando and Pasco Counties become more resilient to flooding. 28

29 Questions Contact Information Mark Vieira Emily Dhingra Kevin Slover

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