Planning for SLR Resiliency in Virginia Beach

Transcription

1 Old Dominion University ODU Digital Commons May 18, 2016: The Economic Impacts of Sea-Level Rise in Hampton Roads Hampton Roads Intergovernmental Pilot Project: Meetings Planning for SLR Resiliency in Virginia Beach Brian Batten Dewberry Greg Johnson City of Virginia Beach Follow this and additional works at: pilotproject_meetings_may2016 Part of the Oceanography and Atmospheric Sciences and Meteorology Commons, and the Public Affairs, Public Policy and Public Administration Commons Repository Citation Batten, Brian and Johnson, Greg, "Planning for SLR Resiliency in Virginia Beach" (2016). May 18, 2016: The Economic Impacts of Sea- Level Rise in Hampton Roads This Presentation is brought to you for free and open access by the Hampton Roads Intergovernmental Pilot Project: Meetings at ODU Digital Commons. It has been accepted for inclusion in May 18, 2016: The Economic Impacts of Sea-Level Rise in Hampton Roads by an authorized administrator of ODU Digital Commons. For more information, please contact

2 Planning for SLR Resiliency in Virginia Beach Brian Batten, Ph.D., CFM, Dewberry Greg Johnson, P.E., Shanda Davenport, P.E., CFM, AICP, City of Virginia Beach

3 Outline Local flooding issues Virginia Beach s resiliency stance Synergy of ongoing efforts Overview of Comprehensive SLR Study

4 SLR and Recurrent Flooding

5 Community Issues

6 Flood Complaints

7 Resiliency Viewpoint Ensure the vibrant future of Virginia Beach Core Strategies:

8 Moody s Questionnaire to VB Does the existing/future CIP include spending for mitigation or resiliency? Has your governing body discussed the capital or financial implications of rising sea levels? Has there been an estimate on potential impacts from rising sea levels or flooding? Please discuss how flooding has impacted the city s budget and how flood mitigation efforts may impact future budgets? Have there been any zoning /long-term planning adjustments downtown and along the waterfront to mitigate future flooding impacts? What is management s current view on the potential impact/vulnerabilities in your community from rising sea levels and a heightened risk of extreme weather events?

9 Proactive Project Design Design policy guidelines SLR and Capital Improvement Projects Adopted Recommendations: Explore additional 1.5 ft of SLR in the design and documentation of infrastructure projects 3 ft for major projects Can accommodation be meaningfully achieved? How is design informed by these conditions?

10 Capital Improvement Plan Stormwater Master Plan Synergized Activities Resilient Planning and Infrastructure Water Quality Sea Level Rise Comp. Study

11 Water Quality Challenges Compliance Issues

12 Comprehensive Stormwater Master Plan Little Creek Elizabeth River Lynnhaven River Owl Creek Stormwater management and flood mitigation Stormwater quality improvement TMDLs (TN, TP, TSS, bacteria) Regulatory compliance NPDES MS4, TMDLs Sea level rise and tidal surge North Landing River Back Bay Capital improvement planning and funding

13 Comprehensive SLR/Recurrent Flooding Study Flood risk assessment Combined flooding Adaptation strategy formulation Policy and Planning Risk Aggregation Strategy evaluation Feasibility Return on Investment Watershed-based adaptation plans Policy, Comprehensive Plan Capital improvement planning and funding

14 Comprehensive SLR Study Approach

15 Informed Resiliency Planning

16 Phase 1: Impact Assessment How will vulnerability change with increasing flood levels due to SLR? Where will we see the flood footprint expand? How much more frequent will flooding occur? What assets are vulnerable? How will losses change? How will insurance requirements change? What assets are at the highest risk?

17 VB SLR Scenarios Life Cycle Alignment Time Horizon/ Time Period SLR Value Relevance Use Municipal Planning years ft Comprehensive Plan & Outcomes Short end of Commercial and Utility life-cycles Vulnerability assessment Key planning value Basis for evaluation of all adaptation strategies Critical Infrastructure Long-term awareness Adaptive Capacity years ft Utility Infrastructure life-cycle Transportation infrastructure lifecycles Residential structure lifecycles Secondary vulnerability assessment to provide insight into long-term risk Basis for long-term infrastructure decisions Evaluate cost-effectiveness of additional protection for adaptable resilience strategies

18 Selected Scenarios vs Federal Curves 3 ft 1.5 ft Action Evaluate for Adaptive Capacity

19 Assessment Conditions Tidal Future permanent inundation Nuisance Repetitive losses/issues Storm Surge Regulatory, disaster scenarios, economics

20 Hazard Evaluation Process Flood Stillwater Surfaces Combined Flooding Floodplain Delineation Depth Grids Total Flood Elevation Surface Wave Hazard Modeling Evaluation/ Summarization Exposure/Risk Analyses

21 Long-term Changes in Surge Propagation

22 Combined Flood Conditions

23 Bringing together the elements Coastal Flooding Stormwater Conveyance Combined Flooding

24 Results: Existing Condition 10-yr coastal surge/10-yr 24-hr duration rainfall Change in Flood Exposure (mi 2 ) Structure Flood Depths Coastal Only = 1.25 Combined Flooding = 1.56 Difference = 0.31 Change in Building Exposure Coastal Only = 277 Combined Flooding = 957 Difference = 680

25 Sensitivity of Loss Analysis

26 Risk Assessment Focus Areas: Shoreline/Land Vulnerability Building Exposure Future Development Stormwater Groundwater Roads Public Utilities Agricultural Societal

27 Building Loss Model Hazus FEMA-backed Nationally applicable standardized methodology Loss models for estimation of earthquakes, floods and hurricanes GIS-based Hazus Flood Module Building-level loss analysis Isolate specific recurrence intervals Annualized loss

28 Hazus - Levels of Analyses Building-level Risk Assessments Other Specific Updates: Essential Facilities Roadway Bridges Primary Utility Features General Building Stock Update from Building-level Information Input Detailed Engineering / Hazard Data Level 3 Combinations of local and default hazard, building, and damage data Level 2 Default hazard, inventory, and damage information Level 1

29 Loss Estimation Process Flood Hazard Data Data Improvement Model Built Environment Perform Damage/Loss Estimation Assign Depth Damage Function Summarize Results Evaluate Economic and Social Impacts

30 Building Data Improvement Cost/Valuation adjustments Inflation Quality Garage sq ft Data gap filling across multiple attributes via web-based mapping resources, neighborhood trends Occupancy type cross-referencing Foundation/construction type standardization/verification Proper breakout of multi-family homes Commercial type ID via Google API First Floor Heights assignment through on multiple sources, gaps filled with validated linear regression-based equation

31 First Floor Height Regression Analyses General form of Multi-Variable Linear Regression: FFH = X 0 + a 1 X 1 + a 2 X a N X N Predictor Variables: Occupancy(x1), Year Built(x2), Foundation Type(x3) and Grade Difference (x4) Two sets of equations, based on year built: Prior to 2004: FFFFFF iiii ffffffff 0.96 iiii RRRRRRR = iiii RRRRRRRRR XX iiii RRRRRRRRR XX1 On or after 2004: FFFFFF iiii ffffffff = iiii RRRRRRR XX iiii PPPPPPPP 0.39 iiii CCCCCCCCCCCCCCCCCCCC XX XX iiii PPPPPPPP 1.31 iiii CCCCCCCCCCCCCCCCCCCC XX XX 4

32 First Floor Height Error Improvements ERROR STATISTICS Avg error drop: 32% Largest drop for Pile foundations: 46%

33 Hazus Flood Loss Outputs Direct Economic Losses Square Footage Damage % Damage Counts of Damaged Structures Total Loss Building Loss Contents Loss Inventory Loss Relocation Cost Income Loss Rental Income Loss Wage Loss Direct Output Loss Employment Loss Building Type Vehicle Damage and Loss Debris Generation Displaced Population and Short Term Needs

34 Hazus Flood Loss Outputs Indirect Economic Losses for Income & Employment within the following Market Sectors: Agriculture Mining Construction Manufacturing Transportation Trade Finance Services Government Miscellaneous TOTAL

35 Loss Changes from Today to 1.5 ft SLR Fold Increase Over Today 10 Year 25 Year 50 Year 100 Year 500 Year AAL

36 Insurance Economic Analysis Current Conditions: Policy/claim concentration Under-insurance issues on current policies in force Future Conditions & Regulatory Changes: Changes to insurance liabilities and residual risks Identify and prioritize mitigation of high risk assets Promotion of increased flood insurance penetration outside existing SFHA Flood Insurance Affordability: Cost burden of flood insurance to socio-economic vulnerable areas

37 Geographic Conflation Framework

38 Geographic Units Low Moderate-Low Low Low Low Moderate-High Moderate-Low Moderate-Low Moderate-Low High Moderate-High Moderate-High Moderate-High High High High

39 Loss Change Summarization Existing Condition 1.5 ft SLR Low Mild Moderate High Severe Low Mild Moderate High Severe

40 Distribution and Magnitude of Loss

41 Phase 2: Adaptation Strategies Objective: Develop, assess and prioritize a range of adaptation strategies through feasibility and performance metrics that incorporate stakeholder input to inform climate adaptation and resilience plans across the City s diverse geography. What strategies are needed to address the risk portfolio? What policy has to be created or changed? How can land use be managed? Where do structural solutions make sense? What s the return on investment? What strategies work best? When should implementation occur?

42 Environmental, Economic Diversity

43

44 Adaptation Tools

45 Phase 3: Implementation Objective: Integrate the best-performing adaptation strategies in actionable watershed-based climate adaptation and resilience plans that include funding and monitoring mechanisms to stimulate follow-on implementation. How do we move forward with the preferred solutions? What are the costs and design features? How do we fund? What is our action plan for each watershed? How do we get public buy-in, sponsors, and/or regional support?

46 Outreach - Integration Engage Coordinate Leverage Partners: HRPDC ODU/Virginia Sea Grant Georgetown Climate Center

47 Questions? Points of Contact: City of Virginia Beach Department of Public Works Greg Johnson, P.E Shanda Davenport, P.E., CFM, AICP Dewberry Brian Batten, Ph.D., CFM