May 22, 2012 Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan ASFPM 2012 Annual Conference Timothy J. Trautman, P.E., CFM Flood Mitigation Program Manager Charlotte-Mecklenburg Storm Water Services Darrin R. Punchard, AICP, CFM Senior Project Manager AECOM

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Agenda Overview Flood Risk Scoring System Risk Reduction Recommendations Flood Mitigation Priority Scores Pilot Study Process Keys to Success 2

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Purpose of the Plan 3 Recommend specific flood mitigation techniques at a building or parcel level Assist in planning, prioritizing and funding future flood mitigation projects Use a new, comprehensive and holistic approach Create a broader and more inclusive risk-based strategy

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan What’s Unique About This Plan 4 Determine Individualized Flood Risk Develop Public & Private Risk Reduction Actions Prioritize Flood Mitigation Projects Implement Balanced Flood Mitigation Capital Program

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan The Need for This Plan 5 Under the Previous Plan –Successfully implemented the acquisition and demolition of 200+ flood-prone structures –Very few properties remain that are deemed cost-effective under FEMA grant requirements –Several significant flood events in recent years –SRL properties and non-compliant buildings Next phase of Capital Improvement Projects

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Overview of the Plan 6 Fully developed plan document, but also very dynamic in nature Fueled by spatial datasets, databases and automated tools –Executive Summary & Introduction –Flood Risk Assessment –Risk Reduction Recommendations –Flood Mitigation Priority Scores –Planning Process & Plan Maintenance Citizen Review Committee (CRC)

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Concept 7 Flood Risk Property Score Flood Property Damage (Impacts) Storm Probability (Frequency) Structure Location Risk Reduction Recommendations Evaluate all flood mitigation techniques Four recommendation categories Mitigation Priority Scores Accounts for other community benefits & factors not included in flood risk Combined with Risk Score to prioritize: Properties Projects (groups) Risk Assessment & Risk Reduction Plan

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Flood Risk Property Score 8 Part of a larger Flood Risk Scoring System Relative indicator of a property’s risk Analyzes factors related to flood impacts, storm frequency and structure location

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Flood Risk Factors 9 –Finished Floor Elevation (living space) –Frequency of flooding –Location within the floodplain (including velocity zones) –Crawl space –Mechanical and electrical systems –Vehicles –Ingress/egress from the building and property –Exterior improvements (detached garages, sheds, pools, etc.) –Number of dwelling units impacted

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Flood Risk Example 10

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan What This Looks Like 11 Detached Garage Velocity ZoneCommunity Encroachment Area Line Parking Area Source of Flooding

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Risk Reduction 12 Guide for public and private flood mitigation activities Analyzes the effectiveness and appropriateness of flood mitigation techniques for each property

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan13

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan 19 Mitigation Techniques 14 1.Property Acquisition and Structure Demolition 2.Structure Demolition and Rebuild 3.Property Acquisition and Structure Relocation 4.Property Acquisition, Demolition or Relocation, and Re-sale 5.Structure Elevation 6.Abandon Basement and Fill 7.Dry Floodproofing of Structures 8.Wet Floodproofing of Structures 9.Audible Flood Warning System for Individual Property 10.Storm Water Detention Facilities 11.Storm Water System Control 12.Automated Flood Notifications 13.Public Education 14.Flood Insurance 15.Levee/Floodwall Protection for Multiple Structures 16.Protecting Service Equipment 17.Partial Dry Floodproofing 18.Partial Wet Floodproofing 19.Levee/Wall/Berm for a Single Structure

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Recommendation Categories 15 Each mitigation technique is evaluated and placed into one of four categories: Highly Effective, Recommended The mitigation technique was determined to be highly effective by exceeding the criteria for the effective category and meeting all of the requirements for this category. This category was developed to identify techniques that were highly effective in reducing risk or provided an additional community benefit. Effective The mitigation technique was determined to be feasible and effective by exceeding the minimum criteria and meeting all of the criteria for this category. Further Evaluation Needed The minimum criteria for the mitigation technique is met but further evaluation or additional data is needed to determine if the technique is a viable option. Not Recommended The minimum criteria for the mitigation technique is not met. Therefore, the technique is likely not feasible, effective, or may be cost prohibitive.

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Evaluation Process 16

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan17 Evaluation Process

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan18 “Dashboard” Results

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Analyzing Results 19

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Flood Mitigation Priority Score 20 Used to prioritize flood mitigation efforts across the county Individual properties as well as grouped projects –Community-based benefits –Other factors not included in the Flood Risk Property Score

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Priority Score Factors 21 –Life and human safety –Cost effectiveness –Proximity to other mitigation projects –Property added to flood zone –Repetitive Loss (RL) structure –Property adjacent to publicly owned land –Property located on five-year planned greenway trail –Property located on five-year planned sanitary sewer route –Property intersects with water quality buffer –Property located in an Environmental Focus Area –Property covered by NFIP policy –Historic preservation and cultural asset protection –Other

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Priority Score Example 22

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Pilot Study Process 23 Two areas were used to manually test and refine proposed scoring methods –126 properties –Mix of residential/commercial Results were used to identify and address potential items of concern –Scoring methodology –Data accuracy –Compare with actual flood event data

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Automation 24 Buildings (ECs) Parcels Flood Hazards

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Automation ArcGIS extension 25

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Automation 26

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Automation 27

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Keys to Success 28 Quality data Active involvement from stakeholders Holistic approach to mitigation –Prioritization based heavily on flood risk, but also mitigation feasibility and other important community factors –Capture opportunities to group properties –Capitalize on multi-objective projects to achieve other public benefits

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan29 Questions?

Charlotte-Mecklenburg Flood Risk Assessment and Risk Reduction Plan Communicating Plan Results