City of Forest Hills, Tennessee Multi-Hazard Mitigation Plan
Prepared by AMEC Environment and Infrastructure Hazard Mitigation and Emergency Management Program Nashville, Tennessee
DRAFT
City of Forest Hills, Tennessee Multi-Hazard Mitigation Plan
DRAFT
Prepared by AMEC Environment & Infrastructure Hazard Mitigation and Emergency Management Program Nashville, Tennessee
EXECUTIVE SUMMARY
The purpose of natural hazards mitigation is to reduce or eliminate long-term risk to people and property from natural hazards. The City of Forest Hills developed this multi-hazard mitigation plan to reduce future losses to the City resulting from natural hazards. The plan was prepared pursuant to the requirements of the Disaster Mitigation Act of 2000 and to achieve eligibility for the Federal Emergency Management Agency (FEMA) Hazard Mitigation Assistance (HMA) programs.
The City’s planning process followed a methodology prescribed by FEMA, which began with the formation of a Hazard Mitigation Planning Committee (HMPC) comprised of key stakeholders from the City of Forest Hill, in addition to local, state and federal agencies. The HMPC conducted a risk assessment that identified and profiled hazards that pose a risk to the City of Forest Hills, assessed the City’s vulnerability to these hazards, and examined the capabilities in place to mitigate them. The City is vulnerable to several hazards that are identified, profiled, and analyzed in this plan. Thunderstorms (hail/high winds/lightning), tornadoes, and winter storms are among the hazards that can have a significant impact on the City.
Based upon the risk assessment, the HMPC identified goals and objectives for reducing risk to natural hazards. The goals of this multi-hazard mitigation plan are to:
Goal 1: Reduce the risk of natural hazards to the people, property, and environment of the City of Forest Hills
Goal 2: Improve the capabilities of the City of Forest Hills to mitigate natural hazards and reduce exposure
Goal 3: Promote effective training and educational opportunities regarding natural hazards and risk
Goal 4: Implement the mitigation actions identified in the Local Hazard Mitigation Plan
To meet identified goals and objectives, the plan recommends 15 mitigation actions, which are summarized in the table on the following page. The HMPC also developed an implementation plan for each action, which identifies priority level, background information, ideas for implementation, responsible agency, timeline, cost estimate, potential funding sources, and more.
The multi-hazard mitigation plan has been formally adopted by the City of Forest Hills Board of Commissioners and will be updated within a five-year timeframe.
The City of Forest Hills, Tennessee i Multi-Hazard Mitigation Plan DRAFT
Mitigation Action Matrix
HMPC Action Goals Addressed Hazards Addressed Priority
1. Publish information on the availability of severe weather alerts through Severe Weather; new and innovative ways, such as text messaging, email, and mobile- High Goals 1, 2, 3 Flood enabled webpages.
2. Develop a comprehensive public education program for the natural High Goals 1, 3 Multi-Hazard hazards and risk identified in the Local Hazard Mitigation Plan.
3. Publish information on streets currently designated as priority for snow Winter Storms; High Goals 1, 3 removal and evacuation. Landslides
4. Coordinate with Metropolitan-Nashville Davidson County Office of Emergency Management (OEM) for inclusion of the City of Forest Hills High Goals 1, 2 Multi-Hazard in the Emergency Operations Plan
5. Identify and prioritize, as applicable, capital improvement projects to High Goals 1, 4 Flood address stormwater infrastructure deficiencies and/or problem areas.
6. Develop sheltering plan for severe weather hazards through coordination with OEM and Red Cross, including capability of new City High Goals 1, 2 Multi-Hazard Hall to serve as shelter
7. Update vulnerability assessment for breach of Radnor Lake dam based upon the inundation profile in the USACE 1989 study and updated Medium Goals 1, 2 Dam Failure topography and parcel information for the City of Forest Hills.
8. Identify areas not currently within storm siren coverage and potential Medium Goals,1, 2 Severe Weather locations for additional sirens.
9. Strengthen communication with neighboring communities Medium Goals 1, 2 Multi-Hazard
10. Implement contingency communications plan Low Goals 1, 2 Multi-Hazard
11. Promote safe rooms for individual residences Low Goals 1, 3 Severe Weather
The City of Forest Hills, Tennessee ii Multi-Hazard Mitigation Plan DRAFT
HMPC Action Goals Addressed Hazards Addressed Priority
12. Implement and enforce hillside protection component of zoning Low Goals 1, 4 Landslides ordinance
13. Participate in the floodplain map modernization process with Low Goals 1, 2, 4 Flood Metropolitan Nashville-Davidson County
14. Distribute National Flood Insurance Program information Low Goals 1, 3 Flood
15. Coordinate annual meetings of the City of Forest Hills Hazard Mitigation Planning Committee to monitor, evaluate, and update the multi-hazard Low Goal 4 Multi-Hazard mitigation plan
The City of Forest Hills, Tennessee iii Multi-Hazard Mitigation Plan DRAFT
TABLE OF CONTENTS
Chapters
1 Introduction and Planning Process ...... 1.1
1.1 Purpose ...... 1.1
1.2 Background and Scope ...... 1.1
1.3 The 10-Step Planning Process ...... 1.2 1.3.1 Phase 1: Planning Process ...... 1.4 1.3.2 Phase 2: Risk Assessment ...... 1.7 1.3.3 Phase 3: Mitigation Strategy...... 1.7 1.3.4 Phase 4: Plan Maintenance...... 1.8
2 Community Profile ...... 2.1
2.1 City of Forest Hills Planning Area Profile ...... 2.1 2.1.1 Geography and Topography...... 2.1 2.1.2 Climate ...... 2.1 2.1.3 Population/Demographics ...... 2.3 2.1.4 History ...... 2.3 2.1.5 Economy/Industry ...... 2.4 2.1.6 Agriculture...... 2.5
2.2 Capabilities Summary...... 2.5
3 Risk Assessment ...... 3.1
3.1 Hazard Identification ...... 3.2 3.1.1 Methodology ...... 3.2 3.1.2 Disaster Declaration History ...... 3.3
3.2 Hazard Profiles ...... 3.6 3.2.1 Methodology ...... 3.6 3.2.2 Dam Failure ...... 3.8 3.2.3 Drought ...... 3.10 3.2.4 Earthquake ...... 3.14 3.2.5 Extreme Temperatures ...... 3.21 3.2.6 Flood ...... 3.24 3.2.7 Landslide ...... 3.27 3.2.8 Land Subsidence - Sinkholes ...... 3.30 3.2.9 Thunderstorms (hail/high winds/lightning) ...... 3.33 3.2.10 Tornado ...... 3.38
The City of Forest Hills, Tennessee iv Multi-Hazard Mitigation Plan DRAFT
3.2.11 Wildfire ...... 3.41 3.2.12 Winter Storm ...... 3.45 3.2.13 Hazard Profiles Summary ...... 3.49
3.3 Vulnerability Assessment ...... 3.50 3.3.1 Methodology ...... 3.50 3.3.2 Community Asset Inventory...... 3.51 3.3.3 Social Vulnerability ...... 3.55 3.3.4 Estimating Potential Losses by Hazard ...... 3.57 3.3.5 Future Land Use and Development ...... 3.62
3.4 Summary of Key Issues ...... 3.62
4 Mitigation Strategy ...... 4.1
4.1 Goals and Objectives...... 4.1
4.2 Identification and Analysis of Mitigation Actions ...... 4.3
4.3 Implementation of Mitigation Actions ...... 4.4
5 Plan Maintenance Process ...... 5.1
5.1 Monitoring, Evaluating, and Updating the Plan ...... 5.1 5.1.1 Hazard Mitigation Planning Committee ...... 5.1 5.1.2 Plan Maintenance Schedule ...... 5.2 5.1.3 Plan Maintenance Process ...... 5.2
5.2 Incorporation into Existing Planning Mechanisms ...... 5.3
5.3 Continued Public Involvement ...... 5.3
Appendices
Appendix A: Adoption Resolution
Appendix B: Planning Process Documentation
Appendix C: Mitigation Alternatives
The City of Forest Hills, Tennessee v Multi-Hazard Mitigation Plan DRAFT
PREREQUISITES
44 CFR requirement 201.6(c)(5): The local hazard mitigation plan shall include documentation that the plan has been formally adopted by the governing body of the jurisdiction requesting approval of the plan. For multi-jurisdictional plans, each jurisdiction requesting approval of the plan must document that it has been formally adopted.
Note to Reviewers: When this plan has been reviewed and approved, pending adoption, by FEMA Region IV, the adoption resolution will be signed by City of Forest Hills Board of Commissioners and added to Appendix A. A model resolution is provided on the following page.
The City of Forest Hills, Tennessee vi Multi-Hazard Mitigation Plan DRAFT
Model Resolution
Resolution # ______
Adopting the City of Forest Hills Multi-Hazard Mitigation Plan Whereas, the (Name of Government/District/Organization seeking FEMA approval of hazard mitigation plan) recognizes the threat that natural hazards pose to people and property within our community; and Whereas, undertaking hazard mitigation actions will reduce the potential for harm to people and property from future hazard occurrences; and Whereas, the U.S. Congress passed the Disaster Mitigation Act of 2000 (“Disaster Mitigation Act”) emphasizing the need for pre-disaster mitigation of potential hazards; Whereas, the Disaster Mitigation Act made available hazard mitigation grants to state and local governments; Whereas, an adopted Multi-Hazard Mitigation Plan is required as a condition of future funding for mitigation projects under multiple FEMA pre- and post-disaster mitigation grant programs; and Whereas, the (Name of Government/District/Organization) fully participated in the FEMA-prescribed mitigation planning process to prepare this Multi-Hazard Mitigation Plan; and Whereas, the Tennessee Emergency Management Agency (TEMA) and the Federal Emergency Management Agency Region IV officials have reviewed the “City of Forest Hills Multi-Hazard Mitigation Plan”, and approved it contingent upon this official adoption of the participating governing body; Whereas, the (Name of Government/District/Organization) desires to comply with the requirements of the Disaster Mitigation Act and to augment its emergency planning efforts by formally adopting the City of Forest Hills Multi-Hazard Mitigation Plan. Whereas, adoption by the governing body for the (Name of Government/District/Organization), demonstrates the jurisdiction’s commitment to fulfilling the mitigation goals and objectives outlined in this Multi-Hazard Mitigation Plan. Whereas, adoption of this legitimacies the plan and authorizes responsible agencies to carry out their responsibilities under the plan. Now, therefore, be it resolved, that the (Name of Government/District/Organization) adopts the “City of Forest Hills Multi-Hazard Mitigation Plan” as an official plan; and Be it further resolved, the (Name of Government/District/Organization) will submit this Adoption Resolution to the Tennessee Emergency Management Agency (TEMA) and Federal Emergency Management Agency Region IV officials to enable the plan’s final approval.
Passed: ______
______Certifying Official
The City of Forest Hills, Tennessee vii Multi-Hazard Mitigation Plan DRAFT 1 INTRODUCTION AND PLANNING PROCESS
1.1 Purpose
The City of Forest Hills has prepared this local hazard mitigation plan to better protect the people and property of the City from the effects of hazard events. This plan demonstrates the community’s commitment to reducing risks from hazards and serves as a tool to help decision makers direct mitigation activities and resources. This plan was also developed to make Forest Hills eligible for certain federal disaster assistance, such as the Federal Emergency Management Agency’s (FEMA) Hazard Mitigation Grant Program and Pre-Disaster Mitigation program.
1.2 Background and Scope
Each year in the United States, natural disasters take the lives of hundreds of people and injure thousands more. Nationwide, taxpayers pay billions of dollars annually to help communities, organizations, businesses, and individuals recover from disasters. These monies only partially reflect the true cost of disasters, because additional expenses to insurance companies and non- governmental organizations are not reimbursed by tax dollars. Many natural disasters are predictable, and much of the damage caused by these events can be alleviated or even eliminated.
Hazard mitigation is defined by FEMA as “any sustained action taken to reduce or eliminate long-term risk to human life and property from a hazard event.” The results of a three-year, congressionally mandated independent study to assess future savings from mitigation activities provides evidence that mitigation activities are highly cost-effective. On average, each dollar spent on mitigation saves society an average of $4 in avoided future losses in addition to saving lives and preventing injuries (National Institute of Building Science Multi-Hazard Mitigation Council 2005).
Hazard mitigation planning is the process through which hazards that threaten communities are identified, likely impacts of those hazards are determined, mitigation goals are set, and appropriate strategies to lessen impacts are determined, prioritized, and implemented. This plan documents the City of Forest Hills’s hazard mitigation planning process and identifies relevant hazards and vulnerabilities and strategies the City will use to decrease vulnerability and increase resiliency and sustainability.
The City of Forest Hills Multi-Hazard Mitigation Plan geographically covers everything within the City’s jurisdictional boundaries (hereinafter referred to as the “planning area”).
This plan was prepared pursuant to the requirements of the Disaster Mitigation Act of 2000 (Public Law 106-390) and the implementing regulations set forth by the Interim Final Rule published in the Federal Register on February 26, 2002, (44 CFR §201.6) and finalized on
The City of Forest Hills, Tennessee 1.1 Multi-Hazard Mitigation Plan DRAFT October 31, 2007. (Hereafter, these requirements and regulations will be referred to collectively as the “Disaster Mitigation Act.”) While the act emphasized the need for mitigation plans and more coordinated mitigation planning and implementation efforts, the regulations established the requirements that local hazard mitigation plans must meet in order for a local jurisdiction to be eligible for certain federal disaster assistance and hazard mitigation funding under the Robert T. Stafford Disaster Relief and Emergency Act (Public Law 93-288). Because the City planning area is subject to many kinds of hazards, access to these programs is vital.
Information in this plan will be used to help guide and coordinate mitigation activities and decisions for local land use policy in the future. Proactive mitigation planning will help reduce the cost of disaster response and recovery to communities and their residents by protecting critical community facilities, reducing liability exposure, and minimizing overall community impacts and disruptions. The City of Forest Hills planning area has been affected by hazards in the past and is thus committed to reducing future impacts from hazard events and becoming eligible for mitigation-related federal funding.
1.3 The 10-Step Planning Process
Requirements §201.6(b) and §201.6(c)(1): An open public involvement process is essential to the development of an effective plan. In order to develop a more comprehensive approach to reducing the effects of natural disasters, the planning process shall include: 1) An opportunity for the public to comment on the plan during the drafting stage and prior to plan approval; 2) An opportunity for neighboring communities, local and regional agencies involved in hazard mitigation activities, and agencies that have the authority to regulate development, as well as businesses, academia, and other private and nonprofit interests to be involved in the planning process; and 3) Review and incorporation, if appropriate, of existing plans, studies, reports, and technical information. [The plan shall document] the planning process used to develop the plan, including how it was prepared, who was involved in the process, and how the public was involved.
The City of Forest Hills recognized the need and importance of a local hazard mitigation plan and initiated its development. The City contracted with AMEC Earth & Environmental (AMEC) to facilitate and develop the plan. AMEC’s role was to:
Assist in establishing the Hazard Mitigation Planning Committee (HMPC) as defined by the Disaster Mitigation Act (DMA); Meet the DMA requirements as established by federal regulations and following FEMA’s planning guidance; Facilitate the entire planning process;
The City of Forest Hills, Tennessee 1.2 Multi-Hazard Mitigation Plan DRAFT Identify the data requirements that HMPC participants could provide and conduct the research and documentation necessary to augment that data; Assist in facilitating the public input process; Produce the draft and final plan documents; and Coordinate the Tennessee Emergency Management Agency and FEMA Region IV plan reviews.
AMEC established the planning process for the City of Forest Hills Multi-Hazard Mitigation Plan using the DMA planning requirements and FEMA’s associated guidance. This guidance is structured around a four-phase process:
1) Planning Process 2) Risk Assessment 3) Mitigation Strategy 4) Plan Maintenance
Into this process, AMEC integrated a more detailed 10-step planning process used for FEMA’s Community Rating System (CRS) and Flood Mitigation Assistance programs. Thus, the modified 10-step process used for this plan meets the requirements of six major programs: FEMA’s Hazard Mitigation Grant Program, Pre-Disaster Mitigation program, Community Rating System, Flood Mitigation Assistance Program, Severe Repetitive Loss program, and new flood control projects authorized by the U.S. Army Corps of Engineers.
Table 1.1 shows how the modified 10-step process fits into FEMA’s four-phase process.
Table 1.1. Mitigation Planning Processes Used to Develop the City of Forest Hills Multi- Hazard Mitigation Plan
DMA Process Modified CRS Process 1) Planning Process 201.6(c)(1) 1) Organize the Planning Effort 201.6(b)(1) 2) Involve the Public 201.6(b)(2) and (3) 3) Coordinate with Other Departments and Agencies 2) Risk Assessment 201.6(c)(2)(i) 4) Identify the Hazards 201.6(c)(2)(ii) 5) Assess the Risks 3) Mitigation Strategy 201.6(c)(3)(i) 6) Set Goals 201.6(c)(3)(ii) 7) Review Possible Activities 201.6(c)(3)(iii) 8) Draft an Action Plan 4) Plan Maintenance 201.6(c)(5) 9) Adopt the Plan 201.6(c)(4) 10) Implement, Evaluate, and Revise the Plan
The City of Forest Hills, Tennessee 1.3 Multi-Hazard Mitigation Plan DRAFT 1.3.1 Phase 1: Planning Process
Planning Step 1: Organize the Planning Effort
A Hazard Mitigation Planning Committee (HMPC) was created for the City of Forest Hills and included representatives from the Board of Commissioners, officials of the City, City Staff, citizens and other local, state, and federal organizations responsible for making decisions in the plan and agreeing upon the final contents. The agencies or organizations listed in Table 1.1 participated on the HMPC.
Table 1.2. Hazard Mitigation Planning Committee – Participating agencies and organizations
Hazard Mitigation Planning Committee Members
Al Deck, City Manager Matt Foster, City Attorney Brad Bivens, City Engineer Mort Stein, City Planner Bill Coke, Board of Commissioners John Lovell, Board of Commissioners Tim Douglas, Board of Commissioners David Waller, Planning Commission Lanson Hyde, Board of Zoning Appeals Clay Jackson, Cultural and Natural Resources Kevin Penney, Metro Office of Emergency Management and local resident
The DMA planning regulations and guidance stress that each local government seeking FEMA approval of their mitigation plan must participate in the planning effort in the following ways:
Participate in the process as part of the HMPC; Detail areas within the planning area where the risk differs from that facing the entire area; Identify potential mitigation actions; and Formally adopt the plan.
For the City of Forest Hills planning area’s HMPC, “participation” meant the following:
Attending and participating in the HMPC meetings; Providing requested data (as available); Reviewing and providing comments on plan drafts; Advertising, coordinating, and participating in the public input process; and Coordinating the formal adoption of the plan by the governing boards.
The City of Forest Hills, Tennessee 1.4 Multi-Hazard Mitigation Plan DRAFT The planning process officially began with a kick-off meeting in Green Hills, Tennessee, on December 2, 2010. The meeting covered the scope of work and an introduction to the DMA requirements. Participants were provided with a Data Collection Guide, which included worksheets to facilitate the collection of information necessary to support development of the plan. Using FEMA guidance, AMEC designed these worksheets to capture information on past hazard events, identify hazards of concern to each of the participating jurisdictions, quantify values at risk to identified hazards, inventory existing capabilities, and record possible mitigation actions.
The HMPC continued to communicate during the planning process with a combination of face- to-face meetings, phone interviews and email correspondence. The meeting schedule and topics are listed in Table 1.2. The sign-in sheets and meeting minutes for each of the meetings are included in Appendix B.
Table 1.3. Schedule of HMPC Meetings
Meeting Topic Date HMPC #1 Kickoff meeting: introduction to DMA, the planning process, and December 2, 2010 hazard identification HMPC #2 Review of risk assessment; Identification of plan goals and objectives May 6, 2011 HMPC #3 Mitigation action identification and prioritization; discussion of process June 30, 2011 to monitor, evaluate, and update plan
Planning Step 2: Involve the Public
Early discussions with the City of Forest Hills established the initial plan for public involvement. At the kick-off meeting, the HMPC also discussed options for public involvement and agreed to an approach using established public information mechanisms and resources within the community. Public involvement activities included press releases, website postings, a public meeting, and the collection of public comments on the draft plan.
The public meeting was held during the draft-plan development and prior to finalizing the plan as further described in Table 1.3. Where appropriate, stakeholder and public comments were incorporated into the final plan, including the sections that address mitigation goals and strategies. All press releases and website postings are on file with the City of Forest Hills. The plan is Source: City of Forest Hills website; available online at http://www.cityofforesthills.com/ http://www.cityofforesthills.com/
The City of Forest Hills, Tennessee 1.5 Multi-Hazard Mitigation Plan DRAFT Table 1.4. Schedule of Public Meetings
Meeting Topic Meeting Date Meeting Location Plan overview and public comments August 11, 2011 City Hall
Planning Step 3: Coordinate with Other Departments and Agencies
Early in the planning process, the HMPC determined that data collection, mitigation strategy development, and plan approval would be greatly enhanced by inviting state and federal agencies and organizations to participate in the process. Based on their involvement in hazard mitigation planning, their landowner status in the City, representatives from the following agencies were invited to participate on the HMPC:
Tennessee Emergency Management Agency National Weather Service American Red Cross U.S. Army Corps of Engineers
The HMPC also used technical data, reports, and studies from the following agencies and groups:
Metro Office of Emergency Management Metro Tax Appraisers Office Metro Planning Department Metro Public Works Department National Drought Mitigation Center National Oceanic and Atmospheric Administration National Climatic Data Center National Register of Historic Places Natural Resource Conservation Service (formerly the Soil Conservation Service) National Weather Service U.S. Fish and Wildlife Service U.S. Geological Survey
Other Community Planning Efforts and Hazard Mitigation Activities Coordination with other community planning efforts is also paramount to the success of this plan. Hazard mitigation planning involves identifying existing policies, tools, and actions that will reduce a community’s risk and vulnerability to hazards. The City of Forest Hills uses a variety of comprehensive planning mechanisms, such as general plans and ordinances, to guide growth and development. Integrating existing planning efforts and mitigation policies and action strategies into this plan establishes a credible and comprehensive plan that ties into and supports other community programs. The development of this plan incorporated information from the
The City of Forest Hills, Tennessee 1.6 Multi-Hazard Mitigation Plan DRAFT following existing plans, studies, reports, and initiatives as well as other relevant data from neighboring communities and other jurisdictions.
The City of Forest Hills Comprehensive Plan The City of Forest Hills Floodplain Ordinance Metro Nashville-Davidson County Flood Insurance Study Metro Nashville-Davidson County Multi-Hazard Mitigation Plan The City of Forest Hills Zoning Ordinance The City of Forest Hills Subdivision Regulations State of Tennessee Multi-Hazard Mitigation Plan
Other documents were reviewed and considered, as appropriate, during the collection of data to support Planning Steps 4 and 5, which include the hazard identification, vulnerability assessment, and capability assessment.
1.3.2 Phase 2: Risk Assessment
Planning Steps 4 and 5: Identify the Hazards and Assess the Risks
AMEC led the HMPC in an exhaustive research effort to identify and document all the hazards that have, or could, impact the planning area. Data collection worksheets were developed and used in this effort to aid in determining hazards and vulnerabilities and where risk varies across the planning area. Geographic information systems (GIS) were used to display, analyze, and quantify hazards and vulnerabilities. The HMPC also conducted a capability assessment to review and document the planning area’s current capabilities to mitigate risk and vulnerability from hazards. By collecting information about existing government programs, policies, regulations, ordinances, and emergency plans, the HMPC could assess those activities and measures already in place that contribute to mitigating some of the risks and vulnerabilities identified. A more detailed description of the risk assessment process and the results are included in Chapter 3 Risk Assessment.
1.3.3 Phase 3: Mitigation Strategy
Planning Steps 6 and 7: Set Goals and Review Possible Activities
AMEC facilitated brainstorming and discussion sessions with the HMPC that described the purpose and the process of developing planning goals and objectives, a comprehensive range of mitigation alternatives, and a method of selecting and defending recommended mitigation actions using a series of selection criteria. This information is included in Chapter 4 Mitigation Strategy. Additional documentation on the process the HMPC used to develop the strategy is in Appendix C: Mitigation Alternatives and Prioritization.
The City of Forest Hills, Tennessee 1.7 Multi-Hazard Mitigation Plan DRAFT Planning Step 8: Draft an Action Plan
Based on input from the HMPC regarding the draft risk assessment and the goals and activities identified in Planning Steps 6 and 7, AMEC produced a complete first draft of the plan. This complete draft was distributed for HMPC review and comment. Other agencies were invited to comment on this draft as well. HMPC and agency comments were integrated into the second draft, which was advertised and distributed to collect public input and comments. AMEC integrated comments and issues from the public, as appropriate, along with additional internal review comments and produced a final draft for the Tennessee Emergency Management Agency and FEMA Region IV to review and approve, contingent upon final adoption by the governing boards of each participating jurisdiction.
1.3.4 Phase 4: Plan Maintenance
Planning Step 9: Adopt the Plan
In order to secure buy-in and officially implement the plan, the plan was adopted by the City of Forest Hills. The adoption resolution is presented Appendix A.
Planning Step 10: Implement, Evaluate, and Revise the Plan
The true worth of any mitigation plan is in the effectiveness of its implementation. Up to this point in the planning process, all of the HMPC’s efforts have been directed at researching data, coordinating input from participating entities, and developing appropriate mitigation actions. Each recommended action includes key descriptors, such as a lead manager and possible funding sources, to help initiate implementation. An overall implementation strategy is described in Chapter 5 Plan Implementation and Maintenance. A plan update and maintenance schedule and a strategy for continued public involvement are also included in Chapter 5.
The City of Forest Hills, Tennessee 1.8 Multi-Hazard Mitigation Plan DRAFT 2 COMMUNITY PROFILE
Chapter 2 provides a profile of the City of Forest Hills planning area and identifies capabilities already in place in the city to help mitigate hazards addressed in this plan.
2.1 City of Forest Hills Planning Area Profile
2.1.1 Geography and Topography
The City of Forest Hills is located in middle Tennessee south of Nashville in Davidson County, and encompasses 9.47 square miles. Neighboring incorporated cities include: Oak Hill, Berry Hill, and Belle Meade.
The landscape, as described by the name, is predominantly steep, heavily vegetated terrain with predominantly low to medium density residential land use. Otter Creek flows through the south- central section of the City boundaries. A detailed hydraulic study of Otter Creek has defined the regulatory floodplain and floodway within the City. Richland Creek, located in the northwest corner of the City boundaries, does not have a defined regulatory floodplain nor floodway. Both Otter Creek and Richland Creek are a part of the greater Cumberland River Watershed.
Figure 2.1 shows a map of the City of Forest Hills planning area, including major waterways and elevation variation.
2.1.2 Climate
The City of Forest Hills receives an average of 518 inches of rain per year, significantly more than the U.S. average of 36.5 inches. Average annual snowfall is 4.9 inches. The average number of days with any measurable precipitation is 112. On average, there are 205 sunny days per year in Forest Hills. The July average high is 90°F, and the January average low is 28°F. Table 2.1 shows the county’s annual climate averages in comparison to the national averages.
Table 2.1 Forest Hills—Annual Climate Averages
Climate Forest Hills United States Rainfall (in.) 51 36.5 Snowfall (in.) 4.9 25 Precipitation Days 112 100 Sunny Days 205 205 Avg. July High 90 86.5 Avg. Jan. Low 27.9 20.5 Comfort Index (higher=better) 35 44 UV Index 4.6 4.3 Elevation ft. 536 1,060 Sources: http://www.bestplaces.net/city/tennessee/forest_hills#
The City of Forest Hills, Tennessee 2.1 Multi-Hazard Mitigation Plan DRAFT
Figure 2.1 Forest Hills County Planning Area
The City of Forest Hills, Tennessee 2.2 Multi-Hazard Mitigation Plan DRAFT
2.1.3 Population/Demographics
According to the U.S. Census, the population of Forest Hills in 2010 was estimated to be 4,812. Population density was 508 people per square mile. The City’s population increased by 2.2 percent between 2000 and 2010.
Table 2.2 Forest Hills—Population
Jurisdiction 1990 2000 2010 Forest Hills 4,231 4,710 4,812 Source: U.S. Census Bureau
Select Census demographic and social characteristics for Forest Hills are shown in Table 2.3.
Table 2.3 Forest Hills—Demographic and Social Characteristics
Characteristic
Gender/Age (2010 Census) Male 2,399 Female 2,413 Under 18 Years 1,202 65 Years and Over 848 Race/Ethnicity (2010 Census) White 4,608 Hispanic/Latino (Any Race) 56 Other (2005-2009 Estimates) Average Household Size 2.87 High School Grad or Higher (%) 97.5 Source: U.S. Census Bureau, 2010 and 2005-2009 Estimates
2.1.4 History
Nashville was settled by Anglo-Europeans in 1780. As Nashville assumed prominence on the western frontier, a road known as the Natchez Trace was created to provide an overland route for settlers returning from New Orleans. Many settlers in the Ohio and Cumberland River valleys floated on rafts down the Mississippi River to New Orleans to sell their goods. Prior to the invention of the steamboat, western settlers had no choice but to walk home through the wilderness to reach home. In order to provide an improved road, the Natchez Trace was constructed from Nashville to Natchez, Mississippi. Construction on the road began in 1802. Recently it has been discovered that one of the main routes of the Trace extended through what is now Forest Hills. With the decline of travel on the Natchez Trace, this roadbed became known as Compton Road, named for the prominent Compton family of the vicinity.
In the early 19th century relatively few large farms existed within what is now Forest Hills. This was primarily because of the area’s topography of steep forested hills, which proved difficult to The City of Forest Hills, Tennessee 2.3 Multi-Hazard Mitigation Plan DRAFT
till. In the northwest corner of the city limits are rich bottomlands along the tributaries of Richland Creek.
The area was developed as a suburb of Nashville in the wake of the post-World War II population and economic boom. Forest Hills was born as a result of the ensuing conflicts between suburban residents and Nashville city government as Nashville struggled to deal with the ramifications of suburban growth. Since 1970, hundreds of dwellings have been built in Forest Hills, and the community no longer retains many tracts of open space or farmland. Most dwellings are sited on parcels of one to two acres, and only a small number of houses are located on tracts of ten acres or more. Several of the community’s hills and ridges such as the properties along Laurel Ridge Drive and Fredericksburg Drive have also been developed in recent decades.
The growth and development of Forest Hills has resulted in the loss of most of the community’s eighteenth and nineteenth century dwellings. Only a handful of properties dating from this early period remain extant.
2.1.5 Economy/Industry
According to the 2007 Economic Census, the industries that employed the highest percentages of Forest Hill’s labor force were management, professional, and related occupations (68.3%); sales and office occupations (23.5%); service occupations (5.7%); construction (1.4%); and production, transportation, and material moving occupations (1.1%). Select economic characteristics for the City of Forest Hills are shown in Table 2.4.
Table 2.4 Forest Hills—Economic Characteristics, 2005-2009 Estimates
Characteristic Median Families below Household 2.3% 158,839 Poverty Level Income ($)* Individuals Per Capita below Poverty 2.9% 73,165 Income ($) Level Population Median Home 606,600 in Labor 2,397 Value ($) Force Source: U.S. Census Bureau (2005-2009), www.census.gov/
The City of Forest Hills, Tennessee 2.4 Multi-Hazard Mitigation Plan DRAFT
According to the 2007 Economic Census, 2,397 people in the City of Forest Hills labor force with an unemployment rate of 4.8 percent. This figure is less than the state unemployment rate of 10.2 percent. Table 2.5 contains information about City of Forest Hills business establishments and payroll values by occupational sector in 2005-2009.
Table 2.5 Forest Hills—Establishments and Payroll Values by Sector, 2005-2009
No. of Percent of Total Annual Occupational Sector Establishments Total (%) Payroll ($) Retail trade 2 6.7 D Information 2 6.7 D Real estate and rental 5 16.7 D and leasing
Professional, Scientific, 4 13.3 82,000 and Technical Services Administrative and Support and Waste Mang 2 6.7 D and Remediation Srvs Health Care and Social 8 26.7 D Assistance Arts, Entertainment, and 5 16.7 D Recreation Accommodation and food 1 3.3 D services Other Services 1 3.3 D Total 30 -- 82,000 Source: US Census Bureau; Note, an establishment is a single physical location at which business is conducted and/or services are provided. D: Withheld to avoid disclosing data for individual companies; data are included in higher level totals.
2.1.6 Agriculture
Although, even historically, Forest Hills was not very heavy in agriculture due to the steep forested nature of the area, a few large farms existing in the 19th century in the northwest corner of the city limits in the rich bottomlands along the tributaries of Richland Creek. Fertile farming lands were also located along Otter Creek. Farming primarily ended in the 1070s when the majority of farmland was purchased and split into smaller residential lots. Very little agriculture is currently conducted in Forest Hills.
The City of Forest Hills, Tennessee 2.5 Multi-Hazard Mitigation Plan DRAFT
2.2 Capabilities Summary
Table 2.6 summarizes the existing regulatory tools and planning mechanisms for the City of Forest Hills. These plans, codes, and ordinances form a framework that supports this hazard mitigation plan. It is expected that future updates of these planning mechanisms will acknowledge, integrate, and implement this hazard mitigation plan, as necessary and appropriate.
Table 2.6 City of Forest Hills—Summary of Mitigation-Related Plans and Policies
Capability City of Forest Hills Comprehensive Plan updated 2010 Emergency Operations Plan N/A, under jurisdiction of OEM Economic Development Plan No commercial parcels Construction of City Hall Capital Improvements Plan and ten year plan Building Code International Building Code Building Code Year 2006 Fire Department ISO Rating N/A Stormwater Management Ordinance Municipal Code Title 14, Ch 5 Stream Management Ordinance No Zoning Management Ordinance 2010, update in progress Subdivision Regulations, Subdivision Regulations update in progress Erosion Management Ordinance No Floodplain Map Yes, 04/20/2001 Floodplain Management Ordinance Yes Elevation Certificates Maintained Yes National Flood Insurance Program Yes Community National Flood Insurance Join Date 09/19/07 NFIP Community Number 470407 NFIP Community Rating System No Number NFIP CRS Effective Date N/A Local Electric Utilities Nashville Electric Service Local Water Utilities Metro Water Services Local Sewage Treatment Utilities Metro Water Services Local Natural Gas Utilities Piedmont Gas Local Telephone Utilities Bell South, Comcast, various Community Has a Fire Insurance N/A Rating Fire Insurance Rating N/A
The City of Forest Hills, Tennessee 2.6 Multi-Hazard Mitigation Plan DRAFT CHAPTER 3 RISK ASSESSMENT
44 CFR Requirement §201.6(c)(2): [The plan shall include] A risk assessment that provides the factual basis for activities proposed in the strategy to reduce losses from identified hazards. Local risk assessments must provide sufficient information to enable the jurisdiction to identify and prioritize appropriate mitigation actions to reduce losses from identified hazards.
The risk assessment process identifies and profiles relevant hazards and assesses the exposure of lives, property, and infrastructure to these hazards. The goal of the risk assessment is to estimate the potential loss in Forest Hills, including loss of life, personal injury, property damage, and economic loss, from a hazard event. The risk assessment process allows Forest Hills to better understand their potential risk to natural hazards and provides a framework for developing and prioritizing mitigation actions to reduce risk from future hazard events.
The risk assessment for Forest Hills and its jurisdictions followed the methodology described in the FEMA publication 386-2, Understanding Your Risks: Identifying Hazards and Estimating Losses (2002), which includes a four-step process:
Identify Hazards Profile Hazard Events Inventory Assets Estimate Losses
This chapter is divided into three parts: hazard identification, hazard profiles, and vulnerability assessment:
Section 3.1 Hazard Identification identifies the hazards that threaten the planning area and describes why some hazards have been omitted from further consideration. Section 3.2 Hazard Profiles discusses the threat to the planning area and describes previous occurrences of hazard events and the probability of future occurrence. Section 3.3 Vulnerability Assessment assesses the City’s total exposure to natural hazards, considering critical facilities and other community assets at risk, and assessing growth and development trends.
The City of Forest Hills, Tennessee Chapter 3-1 Multi-Hazard Mitigation Plan DRAFT
3.1 Hazard Identification
Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the type…of all natural hazards that can affect the jurisdiction.
3.1.1 Methodology
Data on the past impacts and future probability of these hazards in the Forest Hills planning area was collected from the following sources:
o Tennessee State Hazard Mitigation Plan (2010 update), o Nashville/Davidson County Multi-Hazard Mitigation Plan (2010 update), o Information on past extreme weather and climate events from the National Oceanic and Atmospheric Administration’s (NOAA) National Climatic Data Center, o Disaster declaration history from the Federal Emergency Management Agency (FEMA), and the Public Entity Risk Institute, o The National Drought Mitigation Center Drought Reporter, o Information provided by members of the Hazard Mitigation Planning Committee, and o Various articles and publications available on the internet (sources are indicated where data is cited).
The HMPC eliminated two hazards from the Tennessee’s State Hazard Mitigation Plan (2010) list of ―Hazards of Prime Concern‖ from further profiling. Those were expansive soils and levee failure. The HMPC determined that the City is not vulnerable to these hazards to a level that would warrant inclusion in this plan.
The HMPC identified 11 natural hazards that have affected Forest Hills historically or that have the potential to affect the City. Listed alphabetically, these hazards are:
Dam Failure Land Subsidence and Sinkholes Drought Thunderstorms (hail, high winds, lightning) Earthquake Tornado Extreme Temperatures Wildfires Flood Winter Storms Landslides
The City of Forest Hills, Tennessee Chapter 3-2 Multi-Hazard Mitigation Plan DRAFT
3.1.2 Disaster Declaration History
One method used by the planning advisory committee to identify hazards was to examine events that triggered federal disaster declarations. Federal and/or state declarations may be granted when the severity and magnitude of an event surpasses the ability of the local government to respond and recover. Disaster assistance is supplemental and sequential. When the local government’s capacity has been surpassed, a state disaster declaration may be issued, allowing for the provision of state assistance. Should the disaster be so severe that both the local and state governments’ capacities are exceeded; a federal emergency or disaster declaration may be issued allowing for the provision of federal assistance.
The federal government may issue a disaster declaration through FEMA, the U.S. Department of Agriculture (USDA), and/or the Small Business Administration. FEMA also issues emergency declarations, which are more limited in scope and do not include the long-term federal recovery programs of major disaster declarations. Determinations for declaration type are based on scale and type of damages and institutions or industrial sectors affected.
A USDA Secretarial disaster declaration provides assistance to farmers and other rural residents, as the result of natural disasters. The City of Forest Hills does not have any rural areas and thus has not had any USDA designations.
Table 3.1 lists federal disaster declarations received in Davidson County which includes the City of Forest Hills from 1994 to 2010. Each of the disaster events affected multiple counties; estimated damages reflect total losses to all counties.
The City of Forest Hills, Tennessee Chapter 3-3 Multi-Hazard Mitigation Plan DRAFT
Table 3.1 Disaster Declaration History in Davidson County, 1994 to Present.
* FEMA Individual & Declaration Declaration Disaster Public Number Date Description Counties Involved Assistance Major Disaster Declarations Benton, Campbell, Cannon, Carroll, Cheatham, Chester, Clay, Crockett County, Davidson, DeKalb, Decatur, Dickson, Dyer, Fayette, Severe Gibson, Giles, Hardeman, Hardin, Haywood, Storms, Henderson, Henry, Hickman, Houston, Flooding, 1909 5/04/2010 Humphreys, Jackson, Lauderdale, Lawrence, $322 million Straight-Line Lewis, Macon, Madison, Marshall, Maury, Winds, and McNairy, Montgomery, Obion, Perry, Pickett, Tornadoes Putnam, Robertson, Rutherford, Shelby, Smith, Stewart, Sumner, Tipton, Trousdale, Wayne, Williamson, and Wilson.
Benton, Cannon, Carroll, Cheatham, Severe Storms Cumberland, Davidson, Dickson, Dyer, Fayette, 1634 4/05/2006 $14 million and Tornadoes Gibson, Haywood, Maury, Sumner, Warren, and Weakley.
Anderson, Bedford, Benton, Bledsoe, Blount, Bradley, Cannon, Carroll, Cheatham, Chester, Cocke, Coffee, Crockett, Cumberland, Davidson, DeKalb, Decatur, Dickson, Dyer, Fayette, Gibson, Giles, Hamilton, Hardeman, Hardin, Severe Haywood, Henderson, Henry, Hickman, Houston, Storms, Humphreys, Jefferson, Knox, Lauderdale, 1464 5/08/2003 $60 million Tornadoes and Lawrence, Lewis, Lincoln, Loudon, Macon, Flooding Madison, Marion, Marshall, Maury, McMinn, Meigs, Monroe, Montgomery, Morgan, Obion, Perry, Polk, Rhea, Roane, Robertson, Rutherford, Sequatchie, Sevier, Shelby, Smith, Stewart, Sumner, Tipton, Trousdale, Warren, Wayne, Weakley, Williamson, and Wilson.
Severe Anderson, Benton, Cheatham, Davidson, Henry, Storms, Hickman, Houston, Jackson, Knox, Lake, Obion, 1331 6/12/2000 $3.7 million Tornadoes Perry, Pickett, Stewart, and Weakley. And Flooding
Cheatham, Chester, Davidson, Decatur, Severe Dickson, Hardeman, Hardin, Henderson, Storms, 1275 5/12/1999 Hickman, Houston, Humphreys, Lawrence, $5.3 million Tornadoes and McNairy, Perry, Stewart, Sumner, White, and Flooding Williamson.
Flooding, Anderson, Blount, Bradley, Campbell, Carroll,
Severe Cheatham Claiborne, Crockett, Davidson, 4/20/1998 Not Available Storms, & Dickson, Dyer, Gibson, Giles, Grainger, 1215 Hamblen, Hancock, Hardin, Hawkins, Jefferson, Tornadoes Knox, Lawrence, Loudon, Macon, Madison, Maury, Monroe, Morgan, Pickett, Polk, Rhea,
The City of Forest Hills, Tennessee Chapter 3-4 Multi-Hazard Mitigation Plan DRAFT
* FEMA Individual & Declaration Declaration Disaster Public Number Date Description Counties Involved Assistance Roane, Robertson, Sevier, Shelby, Sumner, Union, Wayne, Williamson, and Wilson. Benton, Carroll, Cheatham, Chester, Clay, Davidson, DeKalb, Decatur, Dickson, Dyer, Gibson, Hardeman, Hardin, Henderson, Henry, Tornadoes, 1167 03/07/1997 Houston, Humphreys, Jackson, Lake, Not Available Hail, Flooding Lauderdale, Madison, McNairy, Montgomery, Obion, Shelby, Stewart, Sumner, Tipton, and Weakley.
Bedford, Benton, Bledsoe, Bradley, Campbell, Cannon, Carroll, Cheatham, Chester, Clay, Coffee, Crockett, Cumberland, Davidson, DeKalb, Decatur, Dickson, Dyer, Fayette, Fentress, Franklin, Gibson, Giles, Greene, Grundy, Hardeman, Hardin, Haywood, Henderson, Henry, Hickman, Houston, 1010 02/28/1994 Ice Storm Humphreys, Jackson, Lauderdale, Lawrence, Not Available Lewis, Lincoln, Macon, Madison, Marshall, Maury, McMinn, McNairy, Meigs, Montgomery, Moore, Morgan, Overton, Perry, Pickett, Polk, Putnam, Robertson, Rutherford, Scott, Sequatchie, Shelby, Smith, Stewart, Sumner, Tipton, Trousdale, Union, Van Buren, Warren, Wayne, Weakley, White, Williamson, and Wilson.
Emergency Declarations Anderson, Blount, Bradley, Campbell, Carroll, Cheatham, Claiborne, Crockett, Davidson, Severe Dickson, Dyer, Gibson, Giles, Grainger, Storms, Hamblen, Hancock, Hardin, Hawkins, Jefferson, 1215 4/20/1998 Not Available Tornadoes and Knox, Lawrence, Loudon, Macon, Madison, Flooding Maury, Monroe, Morgan, Pickett, Polk, Rhea, Roane, Robertson, Sevier, Shelby, Sumner, Union, Wayne, Williamson, and Wilson.
Sources: Federal Emergency Management Agency, www.fema.gov/; Public Entity Risk Institute, www.peripresdecusa.org/ *Only FEMA’s portion of Individual and Public Assistance funds obligated for the entire disaster.
The City of Forest Hills, Tennessee Chapter 3-5 Multi-Hazard Mitigation Plan DRAFT
3.2 Hazard Profiles
Requirement §201.6(c)(2)(i): [The risk assessment shall include a] description of the…location and extent of all natural hazards that can affect the jurisdiction. The plan shall include information on previous occurrences of hazard events and on the probability of future hazard events.
3.2.1 Methodology
Each profile describes the hazard and its potential impacts, its location in the community, previous occurrences, and its probability of future occurrences. Profiles then go on to explore vulnerability and potential losses. The magnitude of the impact of a hazard event (past and perceived) is related directly to the vulnerability of the people, property, and the environment it affects. This is a function of when the event occurs, the location affected, the resilience of the community, and the effectiveness of the emergency response and disaster recovery efforts.
The level of information presented in the profiles varies by hazard based on the amount of information available. Resources used to compile these profiles are cited individually in each hazard section. With each update of this plan, new information will be incorporated to provide for better evaluation and prioritization of the hazards that affect the City of Forest Hills.
Detailed profiles for each of the identified hazards include information categorized as follows:
Hazard Description
This section consists of a general description of the hazard and the types of impacts it may have on a community.
Geographic Location
This section describes the geographic extent or location of the hazard in the planning area. Where available, maps are utilized to indicate the areas of the planning area that are vulnerable to the subject hazard. The geographic location was assigned a rank as defined in the following manner:
Extensive—50-100 percent of planning area affected. Significant—10-50 percent of planning area affected. Limited—less than 10 percent of planning area affected.
The City of Forest Hills, Tennessee Chapter 3-6 Multi-Hazard Mitigation Plan DRAFT
Previous Occurrences
This section includes information on historic incidents and their impacts based upon the sources described in Section 3.1 Hazard Identification and the information provided by the Hazard Mitigation Planning Committee.
Probability of Future Occurrence
The frequency of past events is used to gauge the likelihood of future occurrences. Where possible, the probability or chance of occurrence was calculated based on historical data. Probability was determined by dividing the number of events observed by the number of years and multiplying by 100. This gives the percent chance of the event happening in any given year. An example would be three droughts occurring over a 30-year period, which suggests a 10 percent chance of a drought occurring in any given year. The probability was assigned a rank as defined in the following manner:
Highly Likely—Near 100 percent chance of occurrence next year or happens every year. Likely—10-100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less. Occasional—1-10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years. Unlikely—Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years.
Magnitude/Severity
The magnitude of the impact of a hazard event (past and perceived) is related directly to the vulnerability of the people, property, and the environment it affects. This is a function of when the event occurs, the location affected the resilience of the community, and the effectiveness of the emergency response and disaster recovery efforts.
The magnitude of each profiled hazard is classified in the following manner:
Catastrophic—Multiple deaths; property destroyed and severely damaged; and/or interruption of essential facilities and service for more than 72 hours. Critical—Isolated deaths and/or multiple injuries and illnesses; major or long-term property damage that threatens structural stability; and/or interruption of essential facilities and services for 24-72 hours. Limited— Minor injuries and illnesses; minimal property damage that does not threaten structural stability; and/or interruption of essential facilities and services for less than 24 hours.
The City of Forest Hills, Tennessee Chapter 3-7 Multi-Hazard Mitigation Plan DRAFT
Negligible—No or few injuries or illnesses; minor quality of life loss; little or no property damage; and/or brief interruption of essential facilities and services.
3.2.2 Dam Failure
Description
Dams are man-made structures built for the purpose of power production, agriculture, water supply, recreation, and flood protection.
Dams are usually designed to withstand a flood with a computed risk of occurrence. For example, a dam or levee may be designed to contain a flood at a location on a stream that has a certain probability of occurring in any one year. If a larger flood occurs, then that structure will be overtopped. Overtopping is the primary cause of earthen dam failure. Failed dams or levees can create floods that are catastrophic to life and property because of the tremendous energy of the released water and the amount of development located within the area protected by the dam or levee.
Dams and levees typically are constructed of earth, rock, concrete, or mine tailings. Two factors which influence the potential severity of a full or partial dam failure include:
The amount of water impounded; and The density, type, and value of development and infrastructure located downstream.
Dam failures can result from any one or a combination of the following causes: Deliberate intention (terrorism); Prolonged periods of rainfall and flooding; Earthquake (liquefaction / landslides); Inadequate spillway capacity, resulting in excess overtopping flows; Internal erosion caused by embankment or foundation leakage or piping; Improper design; Improper maintenance; Negligent operation; and/or Failure of upstream dams on the same waterway.
The City of Forest Hills, Tennessee Chapter 3-8 Multi-Hazard Mitigation Plan DRAFT
Geographic Location
The State requires emergency action plans for all high and significant hazard dams. Dams that fit this specification do not exist within the City of Forest Hills. However, east of the City along Otter Creek is Radnor Lake Dam. Radnor Lake Dam is of earthen construction, 54 feet high with a length of 850 feet. Its capacity is 2,035 acre feet. Normal storage is 1,132 acre feet. It drains an area of 2.3 square miles. Radnor Lake was created by the Louisville and Nashville Railroad Company in 1914, and was initially used for watering steam locomotives and supplying the watering pens for shipped livestock. A concrete spillway weir and floodwall were added to the dam in 1981. The dam is currently owned by Tennessee Department of Environment and Conservation (TDEC) and is inspected each year by the Division of Safe Dams.
Figure 3.1 Radnor Lake Earthen Dam
Source: maps.google.com
Significant—10-50 percent of planning area affected.
Previous Occurrences
There have been no incidents of dam failure affecting the City of Forest Hills.
Probability of Future Occurrences
Dam failure is generally a secondary effect of other causes and hazards’ thus calculating probability is difficult. Based on the past performance of this structure during flooding conditions, the HMPC determined that the probability of this hazard is ―unlikely‖.
The City of Forest Hills, Tennessee Chapter 3-9 Multi-Hazard Mitigation Plan DRAFT
Unlikely—Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years.
Magnitude/Severity
There have been no documented failure upstream from the City or in the City thus the probability of failure is low. If failure were to occur, it could affect people and structures in the inundation path.
Critical—Isolated deaths and/or multiple injuries and illnesses; major or long-term property damage that threatens structural stability; and/or interruption of essential facilities and services for 24-72 hours.
3.2.3 Drought
Description
A drought is a period of drier-than-normal conditions that results in water-related problems. Precipitation (rain or snow) falls in uneven patterns across the country. The amount of precipitation at a particular location varies from year to year but, over a period of years, the average amount is fairly constant. The average monthly precipitation for Nashville is presented in the table below.
Table 3.2 Precipitation Summary (inches) 1948-2010 Southeast Regional Climate Center
Station Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Nashville International 4.35 4.07 4.86 4.16 4.97 3.94 3.77 3.31 3.51 2.79 3.96 4.41 48.11 Airport Old Hickory 3.88 4.18 4.80 4.09 4.95 3.84 3.58 3.06 3.44 2.83 3.93 4.74 47.33 Dam Source: http://www.sercc.com/cgi-bin/sercc/cliMAIN.pl?tn6402
When no rain or only a very small amount of rain falls, soils can dry out and plants can die. When rainfall is less than normal for several weeks, months, or years, the flow of streams and rivers decline, and the water levels in lakes, reservoirs, and wells falls. If dry weather persists and water-supply problems develop, the dry period can become a drought. Lower river levels can also cause transportation interruptions on navigable streams.
A common indicator of drought is the Palmer Drought Severity Index (PDSI). The PDSI is a soil moisture algorithm calibrated for relatively homogeneous regions. It is used by many U.S. government agencies and states to trigger drought relief programs. It was also the first comprehensive drought index developed in the United States. The classifications of the PDSI are presented in the table below.
The City of Forest Hills, Tennessee Chapter 3-10 Multi-Hazard Mitigation Plan DRAFT
Table 3.3 Palmer Classification
Palmer Classifications
4.0 or more Extremely wet
3.0 to 3.99 Very wet
2.0 to 2.99 Moderately wet
1.0 to 1.99 Slightly wet
0.5 to 0.99 Incipient wet spell
0.49 to -0.49 Near normal
-0.5 to -0.99 Incipient dry spell
-1.0 to -1.99 Mild drought
-2.0 to -2.99 Moderate drought
-3.0 to -3.99 Severe drought
-4.0 or less Extreme drought Source: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/cdus/palmer _drought/wpdanote.shtml
The PDSI indicates that for the period of 1895 through 1995 the central portion of Tennessee was in a severe to extreme drought 5 to 10 percent of the time. According to Tennessee Department of Environment and Conservations’ Drought Management Plan (Revised February 2010), the Tennessee Department of Agriculture’s Division of Forestry works in cooperation with local governments to assess the need for bans on open burning on a county basis according to an established set fire risk indicators.
The beginning of a drought is difficult to determine. Several weeks, months, or even years may pass before people recognize that a drought is occurring. The end of a drought can occur as gradually as it began. Dry periods can last for 10 years or more. The first evidence of drought usually is seen in records of rainfall. Within a short period of time, the amount of moisture in soils can begin to decrease. The effects of a drought on flow in streams and rivers or on water levels in lakes and reservoirs may not be noticed for several weeks or months. Water levels in wells may not reflect a shortage of rainfall for a year or more after a drought begins.
Periods of drought are not uncommon in Middle Tennessee. Drought in the City of Forest Hills adversely affects surface and ground water supplies. Drought can also create favorable conditions for wildfires.
The City of Forest Hills, Tennessee Chapter 3-11 Multi-Hazard Mitigation Plan DRAFT
Geographic Location
Drought has occurred in throughout the City of Forest Hills thus the planning area affected is ―extensive‖.
Extensive—50-100 percent of planning area affected.
Previous Occurrences
There have been 16 recorded droughts encompassing the Tennessee and Davidson County area since 1797.
Table 3.4 Historic Drought Years in Tennessee
Year Comment
1985-88 Most severe drought in state’s history
1980-81
1969-71
1966-67
1953-54 Third most severe drought
1940-42 Second most severe drought
1930-31 Fourth most severe drought
1925-26 35-50 % of normal
1913-14
1894-96 Tennessee River-1.5 ft below base level
1887
1877-78
1853-54 Especially bad in Middle Tennessee
1830
1819 Cumberland River lowest since 1784
1797 Especially bad in Middle Tennessee Source: Data by Allen R. Coggins (n.d.) from historic references, an analysis of National Weather Services data and Tennessee Department of Agriculture crop records.
The City of Forest Hills, Tennessee Chapter 3-12 Multi-Hazard Mitigation Plan DRAFT
Probability of Future Occurrences
Lack of precipitation for a given area is the primary contributor to drought conditions. Since precipitation levels cannot be predicted in the long term, it is difficult to determine the probability of future occurrences of drought. Figure 3.2 shows the Palmer Drought Severity Index for the U.S. from 1895-1995. The City of Forest Hills is in a region of central Tennessee that experienced severe and extreme drought 5-10 percent of the time during that 100-year period. Considering this historical data as well as more recent periods of drought, the HMPC determined the probability of future occurrence of drought to be ―occasional‖.
Figure 3.2 Palmer Drought Severity Index
Note: Green square is the approximate location of Forest Hills.
Occasional—1-10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years
Magnitude/Severity
Drought impacts are wide-reaching and may be economic, environmental, and/or societal but for the City of Forest Hills, the severity is ―negligible‖.
Negligible—No or few injuries or illnesses; minor quality of life loss; little or no property damage; and/or brief interruption of essential facilities and services.
The City of Forest Hills, Tennessee Chapter 3-13 Multi-Hazard Mitigation Plan DRAFT
3.2.4 Earthquake
Description
Earthquakes can be one of nature’s most damaging hazards. An earthquake is a shaking or trembling of the earth’s surface caused by the lifting, shifting, breaking, or slipping of a fault line. Stresses in the earth’s outer layer push the sides of the fault together. Stress builds up and rocks slip suddenly, releasing energy in waves that travel through the earth’s crust and cause the shaking that is felt during an earthquake.
Central and southeast United States earthquakes are being monitored and researched by multiple sources such as the U.S. Geological Survey, Center for Earthquake Research and Information at the University of Memphis, Central United Stated Earthquake Consortium, St. Louis University, and the University of Kentucky. Several methods have been developed to quantify the strength of an earthquake. The most recognized methods for measuring earthquake strength are:
Richter Magnitude is a measure of earthquake strength or the amount of energy released. This scale was originally developed by Charles Richter in 1935. Magnitude is expressed in whole numbers and decimals, with each succeeding whole number representing a tenfold increase in the energy released. There is only one Richter value calculated for the epicenter of a specific earthquake. (The epicenter is the location on the surface of the earth directly above where an earthquake originates. It is determined by measuring the amplitudes of ground motion on seismograms.)
Modified Mercalli Intensity Scale is an evaluation of the severity of ground motion at a given location measured relative to the effects of the earthquake on people and property. This scale was developed by Wood and Nueman in 1931, based on Mercalli’s 1902 original version. Intensity is expressed in Roman numerals I – XII. The Mercalli scale is the most effective means of determining the approximate magnitude of a quake that occurred in historic time prior to the advent of uniform seismic detection devices and the Richter Scale.
Table 3.5 Comparison of Richter Magnitude and Modified Mercalli Intensity Scales
Richter Modified Mercalli Scale Effects Magnitude 1-2 I. Instrumental Not felt Felt by only a few people, especially on upper 3 II. Just perceptible floors of tall buildings Felt by people lying down, seated on a hard 3.5 Ill. Slight surface, or in the upper stories of tall buildings Felt indoors by many, by few outside; dishes and 4 IV. Perceptible windows rattle Generally felt by everyone; sleeping people may be 4.5 V. Rather strong awakened 5 VI. Strong Trees sway, chandeliers swing, bells ring, some
The City of Forest Hills, Tennessee Chapter 3-14 Multi-Hazard Mitigation Plan DRAFT
damage from falling objects 5.5 VII. Very strong General alarm; walls and plaster crack Felt in moving vehicles; chimneys collapse; poorly 6 VIII. Destructive constructed buildings seriously damaged 6.5 IX. Ruinous Some houses collapse; pipes break Obvious ground cracks; railroad tracks bent; some 7 X. Disastrous landslides on steep hillsides Few buildings survive; bridges damaged or 7.5 XI. Very disastrous destroyed; all services interrupted (electrical, water, sewage, railroad); severe landslides Total destruction; objects thrown into the air; river 8 Xll. Catastrophic courses and topography altered Source: http://www.cpo.com/home/Portals/2/Media/post_sale_content/PES/PES_Chap_20/TeachingIllustrations/20_1_mercalli_vs_ric hter_scale.pdf
Geographic Location
Forest Hills is within proximity of two seismic zones: the New Madrid Seismic Zone and the Southern Appalachian Seismic Zone, a portion of which is known as the East Tennessee Seismic Zone.
The New Madrid Seismic Zone extends from west-central Mississippi northward past Cape Girardeau, Missouri. The center of this seismic zone is in New Madrid, Missouri, which is approximately 210 miles west of Forest Hills. It is the major source of seismic activity east of the Rocky Mountains. Although activity in the New Madrid Seismic Zone is less frequent than along the West Coast, when tremblers do occur, the destruction covers more than 20 times the area of an equivalent West Coast earthquake because of underlying geology. The largest earthquake in continental United States, according to the U.S. Geological Survey (USGS), occurred on the New Madrid fault in 1811.
The figure below is a schematic map of the New Madrid seismic zone showing major tectonic features, state boundaries, and major rivers. Instrumentally recorded seismicity delineates faults that probably ruptured in 1811-1812. Currently, aseismic structures (dashed lines) may also represent potential earthquake sources such as the Reelfoot rift boundaries, the Commerce geophysical lineament, the Crittendon County fault zone, and the Bootheel lineament.
The City of Forest Hills, Tennessee Chapter 3-15 Multi-Hazard Mitigation Plan DRAFT
Figure 3.3 Schematic Map of New Madrid Seismic Zone
Source: Impact of Earthquakes on the Central USA, Mid-America Earthquake Center
The Southern Appalachian Seismic Zone (SASZ) extends from Alabama to Virginia with the most recent activity extending from northwestern Georgia through east Tennessee (the portion known as the East Tennessee Seismic Zone or ETSZ). The ETSZ is the most active seismic region in the eastern United States. Given the rate of seismicity in the ETSZ, it is somewhat surprising that the largest known earthquake in the ETSZ was the 1973 Alcoa, Tennessee earthquake, which had a magnitude of only 4.6 on the Richter magnitude scale. Several methods have been developed to quantify the strength of an earthquake. The most recognized methods for measuring earthquake strength are:
The City of Forest Hills, Tennessee Chapter 3-16 Multi-Hazard Mitigation Plan DRAFT
Ground Motion Amplification
Ground motion is the movement of the earth’s surface due to earthquakes or explosions. It is produced by waves generated by a sudden slip on a fault or sudden pressure at the explosive source and travels through the earth and along its surface. Ground motion is amplified when surface waves of unconsolidated materials bounce off of or are refracted by adjacent solid bedrock. The seismic hazard in the Metro Nashville/Forest Hills area is shown in Figure 3.4, which uses contour values to indicate the earthquake ground motions that have a common probability of being exceeded in 50 years.
In developing Figure 3.4, the ground motions being considered at a given location are those from all future possible earthquake magnitudes at all possible distances from that location. The ground motion coming from a particular magnitude and distance is assigned an annual probability equal to the annual probability of occurrence of the causative magnitude and distance.
The method assumes a reasonable future catalog of earthquakes, based upon historical earthquake locations and geological information on the recurrence rate of fault ruptures.
When all the possible earthquakes and magnitudes have been considered, a ground motion value is determined such that the annual rate of its being exceeded has a certain value. Therefore, as presented on Figure 3.4 for the given probability of exceedance, two percent, the locations shaken more frequently will have larger ground motions.
The City of Forest Hills, Tennessee Chapter 3-17 Multi-Hazard Mitigation Plan DRAFT
Figure 3.4 Seismic Hazard Map of Tennessee
Thus the entire planning area would be affected by an earthquake tremor.
Limited—less than 10 percent of planning area affected.
Previous Occurrences
In recent history no major earthquake events have affected the City of Forest Hills. Figure 3.5 below presents all earthquakes that have occurred in the Southeast United States from 1970 through 1999. The activity within the New Madrid and Southern Appalachian Seismic Zones is clearly defined as well as the lack of activity within Forest Hills.
The City of Forest Hills, Tennessee Chapter 3-18 Multi-Hazard Mitigation Plan DRAFT
Figure 3.5 Historic Earthquake Events
Source: Center for Earthquake Research and Information; http://folkworm.ceri.memphis.edu/grabbag/SE_epi.html Note: Pink Circle shows the approximate location of Forest Hills.
Probability of Future Occurrences
According to the Tennessee Emergency Management Agency, instead of a prediction of when an earthquake will strike, an estimate of the likelihood of an earthquake recurring within a given time frame should be given:
In all of western Tennessee, an event of magnitude greater than 5.0 can be expected once every year, a magnitude of 6.0 or greater should occur every 50 years, and a magnitude 7.0 or greater should occur every 600 years.
The highest recurrence rate of large earthquakes in Tennessee occurs in the northwestern quadrant of the state.
New zones of relatively small seismicity have been identified near the Georgia-Tennessee border at Chattanooga, and roughly along Interstate 75 between Chattanooga and Knoxville. This area has not been studied enough to ascertain the expectancy of seismic event histories or likelihoods.
The City of Forest Hills, Tennessee Chapter 3-19 Multi-Hazard Mitigation Plan DRAFT
The New Madrid Fault is an active fault, averaging more than 180 events per year that measure 1.0 or more on the Richter scale. This is equivalent to approximately 15 events per month. Events measuring 2.5-3.0 on the Richter scale includes tremors large enough to be felt and are noted annually. Every 18 months, the New Madrid Fault releases a shock of 4.0 or more, capable of local minor damage. Magnitudes of 5.0 or greater occur approximately once per decade, can cause significant damage, and are felt in several states. A damaging earthquake in the New Madrid area (6.0 or greater) occurs about every 80 years (the last one occurred in 1895).
A major earthquake in the New Madrid area (7.5 or greater) happens every 200-300 years (the last one occurred in 1812). It is predicted that there is a 25 percent chance of a disastrous major earthquake by 2040. A New Madrid Fault rupture this size would be felt throughout half the United States and damage would be expected in 20 states or more. Events measuring 6.0- 7.6 have more significant probabilities in the near future. A 6.0 shock has a 90 percent chance of occurring by the year 2040.
Only one or two earthquakes with magnitudes equal to or greater than 3.0 are expected in the SASZ per year. The extrapolated, expected recurrence time for earthquakes with magnitudes of 6.0 or greater in the SASZ is 186 years (Bollinger et al., 1989).
Considering this historical data on earthquakes, the HMPC determined the probability of future occurrence of damaging earthquakes to be ―occasional‖.
Unlikely—Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years.
Magnitude/Severity
Considering the location of the City of Forest Hills in relation to existing fault lines and historic earthquake activity, this hazard’s magnitude/severity is ―limited‖.
Limited— Minor injuries and illnesses; minimal property damage that does not threaten structural stability; and/or interruption of essential facilities and services for less than 24 hours.
The City of Forest Hills, Tennessee Chapter 3-20 Multi-Hazard Mitigation Plan DRAFT
3.2.5 Extreme Temperatures
Description
Extreme temperature events, both hot and cold, can have severe impacts on natural ecosystems, agriculture and other economic sectors, and human health and mortality. The normal monthly temperatures for Forest Hills/Davidson County are presented in the table and figure below.
Table 3.6 Temperature Summary (°F) 1971-2000 Southeast Regional Climate Center
Station Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual
Nashville International 47.0 51.5 60.6 71.0 79.0 86.6 89.8 89.1 82.9 72.3 59.9 50.2 70.0 Airport (Maximum) Nashville International 28.5 31.2 38.9 48.0 57.1 65.4 69.5 68.2 61.1 48.8 38.9 31.5 48.9 Airport (Minimum) Source: http://www.sercc.com/cgi-bin/sercc/cliMAIN.pl?tn6402
Figure 3.6 Normal Monthly Temperatures for Davidson County
Source: http://www.sercc.com/cgi-bin/sercc/cliMAIN.pl?tn6402
The City of Forest Hills, Tennessee Chapter 3-21 Multi-Hazard Mitigation Plan DRAFT
High Temperatures
Temperatures that remain 10 degrees or more above the average high temperature for the region and last for several weeks are defined as extreme heat by FEMA. Humid or muggy conditions, which add to the discomfort of high temperatures, occur when high atmospheric pressure traps damp air near the ground.
In an effort to alert the public to the hazards of prolonged heat and humidity episodes, the National Weather Service devised the "heat index‖. The heat index is an accurate measure of how hot it feels to an individual when the affects of humidity are added to high temperature. Table 3.7 presents heat index values and their potential physical effects.
The National Weather Service will issue a Heat Advisory for Davidson County when daytime heat indices are at or above 105°F and nighttime heat indices are at or above 80°F. An Excessive Heat Warning is issued when the heat index equals or exceeds 115°F for three hours or longer with a minimum heat index of at least 80°F during a 24-hour period. An excessive heat advisory is also issued when heat advisory conditions persist for at least 3 days. In either of these scenarios, the heat becomes dangerous for a large portion of the population.
Those at greatest risk for heat-related illness include infants and children up to four years of age, people 65 years of age and older, people who are overweight, and people who are ill or on certain medications. However, even young and healthy individuals are susceptible if they participate in strenuous physical activities during hot weather. Also, during extreme heat events, infrastructure, energy sources in particular, can be stressed, and long-term extreme heat can stress water sources, particularly if occurring during a period of drought.
Table 3.7 Heat Index Values and Effects
Source: National Weather Service, Heat Index Chart
The City of Forest Hills, Tennessee Chapter 3-22 Multi-Hazard Mitigation Plan DRAFT
Cold Temperatures The National Weather Service will issue a Wind Chill Advisory for Davidson County when wind-chill temperatures are expected to reach –4°F to –20°F. In 2001, NWS implemented an updated Wind Chill Temperature (WCT) index. This index was developed by the National Weather Service to describe the relative discomfort/danger resulting from the combination of wind and temperature. Wind chill is based on the rate of heat loss from exposed skin caused by wind and cold. As the wind increases, it draws heat from the body, driving down skin temperature and eventually the internal body temperature.
Specifically, the new WCT index:
Calculates wind speed at an average height of five feet (typical height of an adult human face) based on readings from the national standard height of 33 feet (10m); Is based on a human face model; Incorporates modern heat transfer theory (heat loss from the body to its surroundings, during cold and breezy/windy days);
Lowers the calm wind threshold to 3 mph; Uses a consistent standard for skin tissue resistance; and Assumes no impact from the sun (i.e., clear night sky). Extreme cold can cause hypothermia (an extreme lowering of the body’s temperature), frostbite and death. Infants and the elderly are particularly at risk, but anyone can be affected. While there are no firm data on hypothermia (cold) death rates, it is estimated that 25,000 older adults die from hypothermia each year. The National Institute on Aging estimates that more than 2.5 million Americans are especially vulnerable to hypothermia, with the isolated elderly being most at risk. About 10 percent of people over the age of 65 have some kind of temperature-regulating defect, and 3-4 percent of all hospital patients over 65 are hypothermic.
Also at risk are those without shelter or who are stranded, or who live in a home that is poorly insulated or without heat. Other impacts of extreme cold include asphyxiation (unconsciousness or death from a lack of oxygen) from toxic fumes from emergency heaters; household fires, which can be caused by fireplaces and emergency heaters; and frozen/burst pipes.
Geographic Location
The City of Forest Hills is susceptible to extreme temperatures throughout the City.
Extensive—50-100 percent of planning area affected.
The City of Forest Hills, Tennessee Chapter 3-23 Multi-Hazard Mitigation Plan DRAFT
Previous Occurrences
There have been 110 recorded extreme temperature events in Davidson County since 1816. Averaged temperature maximums and minimums for each month are shown in Table 3.8.
Table 3.8 Average Maximum and Minimum Temperatures by Month
Average High Average Low Average High Average Low Month Temperature Temperature Month Temperature Temperature January 46 28 July 89 70 February 51 31 August 88 68 March 61 39 September 82 61 April 70 47 October 71 49 May 78 57 November 59 40 June 85 65 December 49 32 Source: http://www.weather.gov/climate/xmacis.php?wfo=ohx
Probability of Future Occurrences
On average, these events have occurred once every 0.5 years, suggesting a similar recurrence period. This hazard’s probability is ―highly likely‖ (event is probable within the calendar year). An extreme heat event is more likely to occur in the summer months of May, June, July, August, and September, and an extreme cold event is more likely to occur in the winter months of November, December, January, February, and March.
Highly Likely—Near 100 percent chance of occurrence next year or happens every year.
Magnitude/Severity
Extreme temperature events are not uncommon for Middle Tennessee. This hazard’s magnitude/severity is ―limited‖.
Limited— Minor injuries and illnesses; minimal property damage that does not threaten structural stability; and/or interruption of essential facilities and services for less than 24 hours.
3.2.6 Flood
Description
Floods are among the most frequent and costly natural disasters in terms of human hardship and economic loss. There are several different types of likely flood events in Tennessee including flash, riverine, and urban stormwater. Regardless of the type of flood, the cause can almost always be attributed to excessive rainfall, either in the flood area or upstream reach.
The City of Forest Hills, Tennessee Chapter 3-24 Multi-Hazard Mitigation Plan DRAFT
The term "flash flood" describes localized floods of great volume and short duration. In contrast to riverine flooding, this type of flood usually results from a heavy rainfall on a relatively small drainage area. Precipitation of this sort usually occurs in the spring and summer.
Riverine floods result from precipitation over large areas. This type of flood occurs in river systems whose tributaries may drain large geographic areas and include many independent river basins. The duration of riverine floods may vary from a few hours to many days. Factors that directly affect the amount of flood runoff include precipitation, intensity and distribution, the amount of soil moisture, seasonal variation in vegetation, snow depth, and water-resistance of the surface areas due to urbanization.
Urban flood events result as land loses its ability to absorb rainfall as it is converted from fields or woodlands to roads, buildings, and parking lots. Urbanization increases runoff two to six times over what would occur on undeveloped terrain. During periods of urban flooding, streets can become swift moving rivers.
All flood events may result in upstream flooding due to downstream conditions such as channel restriction and/or high flow in a downstream confluence stream. This type of flooding is known as backwater flooding.
Geographic Location
The City of Forest Hills is located primarily with in the watershed of Otter Creek which flows into the Little Harpeth River and then into the Harpeth River and eventually into Cumberland River. As part of the National Flood Insurance Program (NFIP), floodplains and floodways on many local streams have been established and are regulated by local floodplain management ordinance. The most recent Flood Insurance Study (FIS) for Forest Hills was published by FEMA in 2001. The FIS includes Flood Insurance Rate Maps (FIRM) that presents the adopted floodplains, floodways, and flood profiles for streams in the City of Forest Hills. Figure 3.7 shows examples of the mapped floodplains in the City of Forest Hills.
The City of Forest Hills, Tennessee Chapter 3-25 Multi-Hazard Mitigation Plan DRAFT
Figure 3.7 Excerpt of Floodplain on Otter Creek from DFIRM 47037C0336 F
Source: FEMA
Limited—less than 10 percent of planning area affected.
Previous Occurrences
According to the National Climatic Data Center Storm Events database, there have been 44 recorded flood events in Davidson County, encompassing the City of Forest Hills, since 1950.
Probability of Future Occurrences
The terms "10 year", "50 year", "100 year" and "500 year" floods are used to describe the estimated probability of a flood event happening in any given year. A 10 year flood has a 10 percent probability of occurring in any given year, a 50 year event a 2 percent probability, a 100 year event a 1 percent probability, and a 500 year event a 0.2 percent probability. While unlikely, it is possible to have two 100 or even 500 year floods within years or months of each other.
The potential for flooding can change and increase through various land use changes and changes to land surface. A change in environment can create localized flooding problems inside and outside of natural floodplains through the alteration or confinement of natural
The City of Forest Hills, Tennessee Chapter 3-26 Multi-Hazard Mitigation Plan DRAFT
drainage channels. These changes can be created by human activities or by other events, such as wildfires, earthquakes, or landslides.
Floods having a 1-percent chance of occurrence in any given year are identified as special flood hazard areas (SFHA). According to the National Climatic Data Center, from 1993 to the present (2010), there were 44 flood events in 17 years. This results in a probability of over 100% for a given year for at least minor flooding. This hazard’s probability for a significant event is ―highly likely‖ (event is probable within the calendar year).
Highly Likely—Near 100 percent chance of occurrence next year or happens every year.
Magnitude/Severity
Critical—Isolated deaths and/or multiple injuries and illnesses; major or long-term property damage that threatens structural stability; and/or interruption of essential facilities and services for 24-72 hours.
3.2.7 Landslide
Description
The term landslide includes a wide range of ground movement, such as rock falls, deep failure of slopes, and shallow debris flows. Although gravity acting on an over-steepened slope is the primary reason for a landslide, there are other contributing factors:
Erosion by rivers, glaciers, or ocean waves create over steepened slopes;
Rock and soil slopes are weakened through saturation by snowmelt or heavy rains;
Earthquakes create stresses that make weak slopes fail;
Earthquakes of magnitude 4.0 and greater have been known to trigger landslides;
Volcanic eruptions produce loose ash deposits, heavy rain, and debris flows; and
Excess weight from accumulation of rain or snow, stockpiling of rock or ore from waste piles or from man-made structures may induce weak slopes to fail.
Landslides constitute a major geologic hazard because they are widespread, occurring in all 50 states, and cause $1 to 2 billion in damages and more than 25 fatalities, on average, each year. Landslides pose serious threats to highways and to structures that support fisheries, tourism, timber harvesting, mining, and energy production, as well as general transportation. Landslides commonly happen concurrently with other major natural disasters such as
The City of Forest Hills, Tennessee Chapter 3-27 Multi-Hazard Mitigation Plan DRAFT
earthquakes and floods, which exacerbate relief and reconstruction efforts. Expanded development and other land uses have increased the incidence of landslide disasters.
Geographic Location
Steep slopes, present throughout the Middle Tennessee area, specifically in south-central Davidson and north-central Williamson Counties, have the potential to be unstable. Landslides have occurred in this area due to construction-altered colluvium soils on steep slopes adjacent to the Highland Rim escarpment. Colluvium soils are derived from the weathering and erosion of the siliceous Fort Payne Formation, and are composed chiefly of silt- to clay-sized fragments of silica with some fragments ranging up to boulder size.
The City of Forest Hills is located directly along the ridges of the Highland Rim escarpment. Additionally, the higher hills with associated landslide slumps are those within the upper Otter Creek watershed and the Beech Creek watershed.
Significant—10-50 percent of planning area affected.
Previous Occurrences
Several landslides occurred in Nashville in the early 1970s. In particular, many landslides occurred in 1975, partially because of heavy rainfall for the year. Approximately 40 slides were visited after the rains of March 11-13, 1975. No structures were damaged due to these slide events, although many resulted in damage ranging from cracking of retaining walls and driveways to failure of dwelling foundations and major damage to walls and other structures.
Most recently, the severe storms and flooding of the May 2010 event caused multiple landslides throughout the City of Forest Hills. There were 53 reported incidents within the community (see Figure 3.8)
Probability of Future Occurrences
Although the physical cause of many landslides cannot be removed, geologic investigations, good engineering practices, and effective enforcement of land use management regulations can reduce landslide hazards.
Likely—10-100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less.
The City of Forest Hills, Tennessee Chapter 3-28 Multi-Hazard Mitigation Plan DRAFT
Figure 3.8 Landslide Events following May 2010 event
The City of Forest Hills, Tennessee Chapter 3-29 Multi-Hazard Mitigation Plan DRAFT
Magnitude/Severity
Critical—Isolated deaths and/or multiple injuries and illnesses; major or long-term property damage that threatens structural stability; and/or interruption of essential facilities and services for 24-72 hours.
3.2.8 Land Subsidence - Sinkholes
Description
Subsidence is caused when the ground above manmade or natural voids collapses. Subsidence can be related to mine collapse, water and oil withdrawal, or natural causes such as shrinking of expansive soils, salt dissolution (which may also be related to mining activities), and cave collapses. The surface depression is known as a sinkhole. If sinkholes appear beneath developed areas, damage or destruction of buildings, roads and rails, or other infrastructure can result. The rate of subsidence, which ranges from gradual to catastrophic, correlates to its risk to public safety and property damage.
Karst is a distinctive topography in which the landscape is shaped by the dissolving action of water on carbonate bedrock (usually limestone, dolomite, or marble). Davidson County is characterized by gently-folded and flat-lying carbonate rocks, indurate limestone, and dolomite that have not been strongly deformed. Dissolution in this region may produce solution, collapse, and cover-collapse sinkholes.
Solution sinkholes form as the limestone dissolves, creating sunken areas in the land surface. Collapse sinkholes form when caves collapse and suddenly drop a portion of the land surface above. Damage to buildings commonly results from collapse of soil and/or rock material into an open void space near or beneath man-made structures.
Ground subsidence into even a small opening may be very costly if a structure sits on the overlying surface. Sinkhole collapses are often unpredicted and sudden, although they occur more frequently after heavy rainfall. Heavy rainfalls increase the soils’ weight and decrease its strength and stability. Construction can also trigger collapses by directing runoff into a vulnerable area, or weakening the cover of an incipient collapse. Finally, lowering of the water table by a nearby well or from quarry pumping can also trigger collapse when the buoyant effect of groundwater is removed.
The City of Forest Hills, Tennessee Chapter 3-30 Multi-Hazard Mitigation Plan DRAFT
Figure 3.9 Collapse Features of Karst Topography
Source: http://www.nationalatlas.gov/articles/geology/a_karst.html
Geographic Location
Figure 3.10 illustrates soil types and the possible location of karst features in Tennessee. The figure basically shows that the City of Forest Hills is mostly underlain with a soil type that is conducive to sinkholes and soil subsidence.
The City of Forest Hills, Tennessee Chapter 3-31 Multi-Hazard Mitigation Plan DRAFT
Figure 3.10 Karst Topography of Tennessee
Source: ky.water.usgs.gov/projects/cjt_karst/index.htm Note: Major karst areas in the Interior Low Plateaus study region. Karst areas underlain by Mississippian limestones are shaded green, and by Ordovician limestones are shaded tan. Grey shading indicates areas with no karst or only minor karst.
Limited—less than 10 percent of planning area affected.
Previous Occurrences While area formations susceptible to sinkhole formations have been noted in Davidson County adjacent to Percy Priest Lake, no noted occurrences of sinkholes have been documented in the City of Forest Hills.
Probability of Future Occurrences
According to the Tennessee Geological Survey, land subsidence is possible in Forest Hills. However based on the infrequency of previous occurrences, this hazard’s probability is ―occasional‖.
Occasional—1-10 percent chance of occurrence in the next year or has a recurrence interval of 11 to 100 years.
The City of Forest Hills, Tennessee Chapter 3-32 Multi-Hazard Mitigation Plan DRAFT
Magnitude/Severity
Magnitude and severity is based upon past events. With no previous occurrences, no reported injuries or damages, this hazard’s magnitude/severity is ―limited‖.
Limited— Minor injuries and illnesses; minimal property damage that does not threaten structural stability; and/or interruption of essential facilities and services for less than 24 hours.
3.2.9 Thunderstorms (hail/high winds/lightning)
Description
Thunderstorms are defined as localized storms, always accompanied by hail, high winds, lightning, heavy rain causing flash flooding (discussed separately in Section 3.2.5) and sometimes tornadoes (discussed separately in Section 3.2.9). Thunderstorms can produce a strong out-rush of wind known as a down-burst, or straight-line winds which may exceed 120 mph. These storms can overturn mobile homes, tear roofs off of houses and topple trees.
According to the National Oceanic and Atmospheric Administration, approximately 10 percent of the thunderstorms that occur each year in the United States are classified as severe. The typical thunderstorm is 15 miles in diameter and lasts an average of 30 minutes. A thunderstorm is classified as severe when it contains one or more of the following phenomena:
Hail measuring ¾ inch or greater; Winds gusting in excess of 50 knots (57.5 mph); or A tornado.
A severe thunderstorm watch is issued by the National Weather Service when the weather conditions are such that a severe thunderstorm is likely to develop. This is the time to locate a safe place in the home and to watch the sky and listen to the radio or television for more information.
A severe thunderstorm warning is issued when a severe thunderstorm has been sighted or indicated by weather radar. At this point, the danger is very serious and it is time to go to a safe place, turn on a battery-operated radio or television, and wait for the "all clear" from authorities.
Hail
Hail can occur when strong rising currents of air within a storm, called updrafts, carry water droplets to a height where freezing occurs. Then the grown ice particles fall to the ground. Severe thunderstorms can produce hail that can be three quarters of an inch or more in
The City of Forest Hills, Tennessee Chapter 3-33 Multi-Hazard Mitigation Plan DRAFT
diameter and fall at speeds more than 100 mph. Hailstones of this size cause more than $1 billion in damages to properties and crops nationwide annually. Large hail can reach the size of grapefruit.
Based on information provided by the Tornado and Storm Research Organization, Table 3.9 describes typical damage impacts of the various sizes of hail.
Table 3.9 TORRO Hailstorm Intensity Scale
Intensity Diameter Diameter Typical Damage Impacts Category (mm) (inches) Size Description Hard Hail 5-9 0.2-0.4 Pea No damage
Potentially 10-15 0.4-0.6 Mothball Slight general damage to plants, crops Damaging Significant 16-20 0.6-0.8 Marble, grape Significant damage to fruit, crops, vegetation Severe 21-30 0.8-1.2 Walnut Severe damage to fruit and crops, damage to glass and plastic structures, paint and wood scored Severe 31-40 1.2-1.6 Pigeon's egg > Widespread glass damage, vehicle bodywork squash ball damage Destructive 41-50 1.6-2.0 Golf ball > Pullet's Wholesale destruction of glass, damage to tiled egg roofs, significant risk of injuries Destructive 51-60 2.0-2.4 Hen's egg Bodywork of grounded aircraft dented, brick walls pitted Destructive 61-75 2.4-3.0 Tennis ball > Severe roof damage, risk of serious injuries cricket ball Destructive 76-90 3.0-3.5 Large orange > Severe damage to aircraft bodywork Soft ball Super 91-100 3.6-3.9 Grapefruit Extensive structural damage. Risk of severe or Hailstorms even fatal injuries to persons caught in the open Super >100 4.0+ Melon Extensive structural damage. Risk of severe or Hailstorms even fatal injuries to persons caught in the open Source: Tornado and Storm Research Organization (TORRO), Department of Geography, Oxford Brookes University Notes: In addition to hail diameter, factors including number and density of hailstones, hail fall speed and surface wind speeds affect severity.
High Winds
A severe thunderstorm can produce winds that can cause as much damage as a weak tornado and these winds can be life threatening. The damaging winds of thunderstorms include downbursts, microbursts, and straight-line winds. Downbursts are localized currents of air blasting down from a thunderstorm, which induce an outward burst of damaging wind on or near the ground. Microbursts are minimized downbursts covering an area of less than 2.5 miles across. They include a strong wind shear (a rapid change in the direction of wind over a short distance) near the surface. Microbursts may or may not include precipitation and can produce winds at speeds of more than 150 miles per hour. Damaging straight-line winds are high winds across a wide area that can reach speeds of 140 miles per hour.
The City of Forest Hills, Tennessee Chapter 3-34 Multi-Hazard Mitigation Plan DRAFT
Figure 3.11 shows the wind zones of the United States based on maximum wind speeds; the City of Forest Hills is located within wind zone IV, the highest inland categories. The entire City is in zone IV. High winds, often accompanying severe thunderstorms, can cause significant property and crop damage, threaten public safety, and have adverse economic impacts from business closures and power loss.
Figure 3.11 Wind Zones of the United States
Lightning
Lightning is defined as any and all of the various forms of visible electrical discharge caused by thunderstorms. According to the National Weather Service, lightning is one of the most underrated severe weather hazards. The second deadliest weather killer in the United States, it ranks above hurricanes or tornadoes with an average of 73 deaths and 300 injuries each year.
Cloud-to-ground lightning can kill or injure people by direct or indirect means. The lightning current can branch off to a person from a tree, fence, pole, or other tall object.
The City of Forest Hills, Tennessee Chapter 3-35 Multi-Hazard Mitigation Plan DRAFT
Similarly, objects can be directly struck and this impact may result in an explosion, fire, or total destruction; or the damage may be indirect when the current passes through or near it. Sometimes current may enter a building and transfer through wires or plumbing, and damaging everything in its path. In urban areas, lightning may strike a pole or tree and the current then travel to several nearby houses and other structures and enter them through wiring or plumbing.
Geographic Location
The entire City is susceptible to severe thunderstorms including hail, high winds and lightning.
Extensive—50-100 percent of planning area affected.
Previous Occurrences
There have been 338 recorded thunderstorm/high wind events in Davidson County since 1872. – need hail, wind & lightning.
Figure 3.12 shows that the City is located in an area with an average of 30-50 days with thunderstorms per year per 10,000 square miles. Figure 3.13 shows frequency of lightning in the City to be approximately four to eight lightning strikes per square kilometer per year.
The City of Forest Hills, Tennessee Chapter 3-36 Multi-Hazard Mitigation Plan DRAFT
Figure 3.12 Average Number of Thunderstorm Days Per Year
Figure 3.13 Location and Frequency of Lightning in Tennessee
Source: National Weather Service, www.lightningsafety.noaa.gov/lightning_map.htm Note: Green square indicates approximate location of Forest Hills
The City of Forest Hills, Tennessee Chapter 3-37 Multi-Hazard Mitigation Plan DRAFT
Probability of Future Occurrences
Thunderstorms are likely to occur in the Forest Hills area approximately 50 to 70 days each year. The last reported lightning event in Forest Hills occurred in 1997 and did $100,000 in property damage.
Highly Likely—Near 100 percent chance of occurrence next year or happens every year.
Magnitude/Severity
There have been 9 lightning events recorded in Davidson County (including the City of Forest Hills) since 1990, according to the National Climatic Data Center. Of the 9 notable events, there have been 19 reported injuries and one death. The total property damage for these nine events is approximately $590,000.
There have been 82 hail events recorded in Davidson County (including the City of Forest Hills) since 1990, according to the National Climatic Data Center. Of the 82 notable events, there have been no reported injuries or deaths or property damage.
There have been 244 thunderstorm wind events recorded in Davidson County (including the City of Forest Hills) since 1990, according to the National Climatic Data Center. Of the 244 notable events, there have been 17 reported injuries. 1 death, and $4.2M in property damage.
This hazard’s magnitude/severity is ―limited‖.
Limited— Minor injuries and illnesses; minimal property damage that does not threaten structural stability; and/or interruption of essential facilities and services for less than 24 hours.
3.2.10 Tornado
Description
The National Weather Service defines a tornado as a violently rotating column of air pendant from a thunderstorm cloud that touches the ground. Tornados are generally considered the most destructive of all atmospheric-generated phenomena. In an average year, more than 800 tornadoes are reported in the United States. More tornados occur during the months of May and June than in other months. Additionally, over 30 percent of recorded tornado activity has occurred between the hours of 3:00 pm and 6:00 pm, and an additional estimated 25 percent has occurred between 6:00 pm and 9:00 pm. Thus, over half of all tornadoes occur between 3:00 and 9:00 pm.
Tornados follow the path of least resistance making valleys and flatter land areas most susceptible. The typical tornado path is 16 miles long with a width of less than one quarter
The City of Forest Hills, Tennessee Chapter 3-38 Multi-Hazard Mitigation Plan DRAFT
mile. Tornadoes have resulted in some of the greatest losses to life of any natural hazard, with the mean national death toll being between 80 and 100 persons every year.
Tornados are classified using the tornado scale developed by Dr. Theodore Fujita. The Fujita Tornado Scale assigns a category to tornados based on their wind speeds and relates this to the general type of damage that is expected. Ratings range from F0 (light damage), to F5 (total destruction). The scale is presented in Table 3.10. Approximately ninety percent of tornados nationwide recorded between 1956 and 2001 were F2, F1, and F0 tornados. Most of these (68 percent of all tornados) were F1 and F0 tornados.
Table 3.10 Fujita Scale
The Enhanced Fujita Scale’s damage indicators and degrees of damage can be found online at www.spc.noaa.gov/efscale/ef-scale.html.
Geographic Location
Figure 3.14 illustrates the number of F3, F4, and F5 tornadoes recorded in the United States per 3,700 square miles between 1950 and 2006. The City of Forest Hills is in the section shaded medium blue, indicating 5-10 tornadoes of this magnitude during this 56-year period. Additionally, as previously shown in Figure 3.11, the City of Forest Hills is in Wind Zone IV, the zone in the U.S. that has experienced the most and the strongest tornado activity.
Extensive—50-100 percent of planning area affected.
The City of Forest Hills, Tennessee Chapter 3-39 Multi-Hazard Mitigation Plan DRAFT
Figure 3.14 Tornado Activity in the United States, 1950-2006
Note: Red Rectangle is the approximate location of Forest Hills, Tennessee.
Previous Occurrences
Several severe tornadoes have passed through the area around Forest Hills, damaging property and taking lives in many of those instances. The tornado that occurred on April 16, 1998 caused the most damage ever in Davidson County because its path was through downtown Nashville. As a result, 35 buildings in downtown Nashville were "red tagged", meaning they were rendered structurally unsound. Nashville Electric Service reported that 75,000 customers were without power.
Probability of Future Occurrences
Based on NOAA, Storm Prediction Center Statistics, Forest Hills is located in an area of High Risk for tornadoes.
Likely—10-100 percent chance of occurrence in next year or has a recurrence interval of 10 years or less.
The City of Forest Hills, Tennessee Chapter 3-40 Multi-Hazard Mitigation Plan DRAFT
Magnitude/Severity
During the 1952 to 2010 time period, there were two reported deaths in the Davidson County area. 103 injuries were reported. Total property damage for events between 1950 and 2010 is estimated at $ 121 million. This hazard’s magnitude/severity is ―critical‖.
Critical—Isolated deaths and/or multiple injuries and illnesses; major or long-term property damage that threatens structural stability; and/or interruption of essential facilities and services for 24-72 hours.
3.2.11 Wildfire
Description
A wildfire is an uncontrollable fire spreading through vegetative fuels, exposing and possibly consuming structures. Wildfires often begin unnoticed and spread quickly and are usually signaled by dense smoke that fills the area for miles around. Generally, there are three major factors that sustain wildfires and allow for predictions of a given area’s potential to burn. These factors include:
Fuel; Topography; and Weather.
Fuel is the material that feeds a fire and is a key factor in wildfire behavior. Fuel is generally classified by type and by volume. Fuels sources are diverse and include everything from dead tree needles, twigs, and branches to dead standing trees, live trees, brush, and cured grasses. Man-made structures and other associated combustibles are also to be considered as a fuel source. The type of prevalent fuel directly influences the behavior of wildfire. Light fuels such as grasses burn quickly and serve as a catalyst for spreading wildfires.
An area’s topography (terrain and land slopes) affect its susceptibility to wildfire spread. Fire intensities and rates of spread increase as slope increases due to the tendency of heat from a fire to rise via convection. The natural arrangement of vegetation throughout a hillside can also contribute to increased fire activity on slopes
Weather components such as temperature, relative humidity, wind, and lightning also affect the potential for wildfire. High temperatures and low relative humidity dry out the fuels that feed the wildfire creating a situation where fuel will more readily ignite and burn more intensely. Wind is the most treacherous weather factor. The issue of drought conditions contributes to concerns about wildfire vulnerability.
The City of Forest Hills, Tennessee Chapter 3-41 Multi-Hazard Mitigation Plan DRAFT
The Wildland-Urban Interface (WUI) is the area where houses meet or intermingle with undeveloped wildland vegetation. This makes the WUI a focal area for human-environment conflicts such as wildland fires, habitat fragmentation, invasive species, and biodiversity decline. Using geographic information systems (GIS), U.S. Census and USGS National Land Cover Data was integrated to map the WUI. The image below presents the identified WUI for Tennessee. The City of Forest Hills is wholly located within the WUI intermix and interface areas. These two components of WUI, intermix and interface, have some differences that are potentially significant in wildland fire management. In terms of fuels, vegetation dominates intermix, and structural fuels dominate interface. Vegetation and structures ignite and burn differently, and thus fire behavior changes with the mix of these two WUI fuel types.
Figure 3.15 Tennessee Wildland Urban Interface 2000
The National Weather Service Fire Weather Program emerged in response to a need for weather support to large and dangerous wildfires. This service is provided to federal and state land management agencies for the prevention, suppression, and management of forest and rangeland fires. The National Weather Service Forecast Office in Nashville provides year- round fire weather forecasts for most of Middle Tennessee. Routine fire weather forecasts are issued daily for Tennessee Division of Forestry Districts 4 and 5 (See Figure 3.16).
The City of Forest Hills, Tennessee Chapter 3-42 Multi-Hazard Mitigation Plan DRAFT
Figure 3.16 Tennessee Fire Districts
Geographic Location
The City is generally a suburban estate community with a few large undeveloped parcels which retain their rural character. This rural character includes wooded or forest areas.
Significant—10-50 percent of planning area affected.
Previous Occurrences
According to the National Climatic Data Center Storm Events database, there have been 0 recorded wildfire events in Davidson County, including the City of Forest Hills, since 1950.
Probability of Future Occurrences
The US Forest Service both observes and forecasts a low fire danger potential for the City of Forest Hills (See Figure 3.17).
Unlikely—Less than 1 percent chance of occurrence in next 100 years or has a recurrence interval of greater than every 100 years.
Magnitude/Severity
Magnitude and severity is based upon past events. With no previous occurrences, no reported injuries or damages, this hazard’s magnitude/severity is ―limited‖.
Limited— Minor injuries and illnesses; minimal property damage that does not threaten structural stability; and/or interruption of essential facilities and services for less than 24 hours.
The City of Forest Hills, Tennessee Chapter 3-43 Multi-Hazard Mitigation Plan DRAFT
Figure 3.17 Observed and Forecast Fire Danger Class
The City of Forest Hills, Tennessee Chapter 3-44 Multi-Hazard Mitigation Plan DRAFT
3.2.12 Winter Storm
Description
Winter storms are especially hazardous in terms of closing emergency routes, creating power and utility system failures, and immobilizing economic activity. Commuters may become stranded, airports may close, and emergency and medical services may be disrupted. Accumulations of snow and ice can cause roofs to collapse and knock down trees and power lines. Ice can disrupt communications and power for days while utility companies repair extensive damage. Even small accumulations of ice can be extremely dangerous to motorists and pedestrians. Bridges and overpasses freeze before other surfaces and are particularly dangerous.
The types of winter precipitation which may occur in Forest Hills include:
Snow Flurries -- Light snow falling for short durations, resulting in a light dusting or no accumulation. Snow Showers -- Snow falling at varying intensities for brief periods of time. Some accumulation possible. Blowing Snow -- Wind-driven snow that reduces visibility and causes drifting. May be falling snow or loose snow picked up off the ground by the wind. Blizzard -- Winds of more than 35 miles per hour with snow and blowing snow reducing visibility to near zero. Sleet -- Forms from rain drops that freeze into ice pellets before reaching the ground. Sleet usually bounces when hitting a surface and does not stick. It can, however, accumulate and make driving treacherous. Typically occurs at temperatures from 30 to 31 degrees on the ground and 32 to 34 degrees in the clouds. Freezing Rain -- Falls onto a surface with a temperature below freezing, causing it to freeze to surfaces such as trees, cars and roads and form a coating of ice. Can be very hazardous even in small accumulations. Typically occurs at temperatures from 30 to 33 degrees on the ground and 34 to 36 degrees in the clouds.
The average monthly snowfall for Davidson County area is presented in the Table 3.11.
The City of Forest Hills, Tennessee Chapter 3-45 Multi-Hazard Mitigation Plan DRAFT
Table 3.11 Average Monthly Snowfall
Geographic Location
Figure 3.18 shows that freezing rains occurs 3-6 hours per year in Forest Hills and most of Tennessee. Figure 3.19 shows moderate winter storm hazard for Forest Hills.
Extensive—50-100 percent of planning area affected.
Figure 3.18 Average Number of Hours per Year with Freezing Rain in the United States
Source: American Meteorological Society. ―Freezing Rain Events in the United States.‖ http://ams.confex.com/ams/pdfpapers/71872.pdf. Note: Star shows approximate location of Forest Hills, Tennessee
The City of Forest Hills, Tennessee Chapter 3-46 Multi-Hazard Mitigation Plan DRAFT
Figure 3.19 Winter Storm Hazards in the United States
The City of Forest Hills, Tennessee Chapter 3-47 Multi-Hazard Mitigation Plan DRAFT
Previous Occurrences
There have been 164 recorded winter storm events in Davidson County, including the City of Forest Hills since 1779.
Averaged snowfall in inches, for each month is shown in Table 3.12.
Table 3.12 Record Snowfall (inches) by Month
Snowfall Snowfall Month (inches) Month (inches) January 3.6 July 0.0 February 3.1 August 0.0 March 1.0 September 0.0 April 0.4 October 0.0 May 0.0 November 0.1 June 0.0 December 0.5 Source: http://www.weather.gov/climate/xmacis.php?wfo=ohx
Probability of Future Occurrences
The City of Forest Hills and Davidson County may anticipate 6 to 12 inches of snowfall annually. This hazard’s probability is ―highly likely‖.
Highly Likely—Near 100 percent chance of occurrence next year or happens every year.
Magnitude/Severity
There have been 19 notable winter weather events reported in Forest Hills since 1994, according to the National Climatic Data Center. Of the 19 notable events, no deaths and 11 injuries were recorded. Damages associated with winter storms in the City are usually related to downed power lines and power infrastructure. These damages and the associated losses as a result of disruptions in normal daily operations can be costly.
One significant winter weather event can have multiple impacts including property damage and damages to power lines and infrastructure from falling trees and limbs, prolonged power outages, road damage, road hazards, and road closures, school, government and business closures.
This hazard’s magnitude/severity is ―critical‖.
Critical—Isolated deaths and/or multiple injuries and illnesses; major or long-term property damage that threatens structural stability; and/or interruption of essential facilities and services for 24-72 hours.
The City of Forest Hills, Tennessee Chapter 3-48 Multi-Hazard Mitigation Plan DRAFT
3.2.13 Summary of Hazard Profiles
This section summarizes the results of the hazard profiles and assigns a level of overall planning significance to each hazard as low, moderate, or high. Significance was determined based on the hazard profile, focusing on key criteria such as frequency and resulting damage, including deaths/injuries and property and economic damage. This assessment was used by the HMPC to prioritize those hazards of greatest significance to the planning area, thus enabling the City of Forest Hills to focus resources where they are most needed. Thos hazards that occur infrequently or have little or no impact of the planning area were determined to be of low significance. Those hazard determined to be of high significance were characterized as priority hazards that required further evaluation in Section 3.3 Vulnerability Assessment.
Table 3.13 Summary of Hazard Profiles
Geographic Planning Hazard Location Probability Magnitude Significance Dam Failure Significant Unlikely Critical Low Drought Extensive Occasional Negligible Low Earthquake Limited Unlikely Limited Low Land Subsidence and Sinkholes Limited Occasional Limited Low Wildfires Significant Unlikely Limited Low Extreme Temperatures Extensive Highly Likely Negligible Moderate Flood Limited Highly Likely Critical Moderate Landslides Significant Likely Critical Moderate Thunderstorms (hail, high winds, lightning) Extensive Highly Likely Limited High Tornado Extensive Likely Critical High Winter Storms Extensive Highly Likely Critical High Source HMPC
The City of Forest Hills, Tennessee Chapter 3-49 Multi-Hazard Mitigation Plan DRAFT
3.3 Vulnerability Assessment
Requirement §201.6(c)(2)(ii): [The risk assessment shall include a] description of the jurisdiction’s vulnerability to the hazards described in paragraph (c)(2)(i) of this section. This description shall include an overall summary of each hazard and its impact on the community.
Requirement §201.6(c)(2)(ii)(A): The plan should describe vulnerability in terms of the types and numbers of existing and future buildings, infrastructure, and critical facilities located in the identified hazard areas.
Requirement §201.6(c)(2)(ii)(B): [The plan should describe vulnerability in terms of an] estimate of the potential dollar losses to vulnerable structures identified in paragraph (c)(2)(i)(A) of this section and a description of the methodology used to prepare the estimate.
Requirement §201.6(c)(2)(ii)(C): [The plan should describe vulnerability in terms of] providing a general description of land uses and development trends within the community so that mitigation options can be considered in future land use decisions.
3.3.1 Methodology
The vulnerability assessment further defines and quantifies populations, buildings, critical facilities, and other community assets at risk to natural hazards. The vulnerability assessment for this plan followed the methodology described in the FEMA publication Understanding Your Risks—Identifying Hazards and Estimating Losses (2002).
The vulnerability assessment was conducted based on the best available data and the significance of the hazard. Data to support the vulnerability assessment was collected from the following sources:
County and jurisdictional GIS data (hazards, base layers, and assessor’s data) Statewide GIS datasets compiled by state and federal agencies FEMA’s HAZUS-MH loss estimation software Existing plans and reports
The vulnerability assessment first describes community assets in the City of Forest Hills, including the total exposure of people and property; critical facilities and infrastructure; natural, cultural, and historic resources; and economic assets. Secondly, the assessment considers the social vulnerability of the City to hazards, including characteristics of gender, age, race/ethnicity, and wealth and poverty. Next, hazards of high and medium significance are evaluated in greater detail and potential losses are estimated where data is available. Development trends, including population growth, housing demand, and land use patterns, are analyzed in relation to hazard-prone areas. The end of the chapter summarizes the key issues and conclusions identified in the risk assessment process.
The City of Forest Hills, Tennessee Chapter 3-50 Multi-Hazard Mitigation Plan DRAFT
3.3.2 Community Assets
This section assesses the population, structures, critical facilities and infrastructure, and other important assets in the City of Forest Hills that may be at risk to natural hazards.
Total Exposure of Population and Structures
Table 3.14 shows the total population, number of structures, and assessed value of improvements to parcels by jurisdiction. Land values have been purposely excluded because land remains following disasters, and subsequent market devaluations are frequently short term and difficult to quantify. Additionally, state and federal disaster assistance programs generally do not address loss of land or its associated value.
Table 3.14. Maximum Population and Building Exposure by Jurisdiction
Population Number of Total Structure Community 2010 Structures Value ($)* Forest Hills 4,812 2,120 $585,451 Sources: HAZUS-MH (MR 5) (structures) *Dollar amounts in thousands
Critical Facilities and Infrastructure
A critical facility may be defined as one that is essential in providing utility or direction either during the response to an emergency or during the recovery operation. FEMA’s HAZUS-MH loss estimation software uses three categories of critical assets. Essential facilities are those that if damaged would have devastating impacts on disaster response and/or recovery, and high potential loss facilities are those that would have a high loss or impact on the community. Transportation and lifeline facilities are the third category of critical assets. Examples of each are provided below.
Essential Facilities High Potential Loss Facilities Transportation and Lifelines Hospitals and other Power plants Highways, bridges, and medical facilities Dams and levees tunnels Police stations Military installations Railroads and facilities Fire stations Hazardous material sites Airports Emergency operations Schools Water treatment facilities centers Shelters Natural gas and oil facilities Day care centers and pipelines Nursing homes Communications facilities Main government buildings
The City of Forest Hills, Tennessee Chapter 3-51 Multi-Hazard Mitigation Plan DRAFT
Table 3.15 is an inventory of critical facilities in the City of Forest Hills, based upon the HMPC. Figure 3.20 displays the locations of these facilities.
Table 3.15. Inventory of Critical Facilities
Facility
City of City Forest Hills Forest Airports 0 Colleges 0 Dams—low hazard 0 Dams—significant hazard 1 Emergency medical services stations 0 Fire stations 0 Health care facilities 0 Power plants 0 Gov’t Bldgs – City Hall 1 Schools 1 Churches/Religious Facilities 4 Totals 7 Source: HAZUS-MH (MR 5) (structures) and HMPC
The City of Forest Hills, Tennessee Chapter 3-52 Multi-Hazard Mitigation Plan DRAFT
Figure 3.20 City of Forest Hills Critical Facilities
The City of Forest Hills, Tennessee Chapter 3-53 Multi-Hazard Mitigation Plan DRAFT
Other Assets
Assessing the vulnerability of the City of Forest Hills to disaster also involves inventorying the natural, historic, cultural, and economic assets of the area. This is important for the following reasons:
The City may decide that these types of resources warrant a greater degree of protection due to their unique and irreplaceable nature and contribution to the overall economy. If these resources are impacted by a disaster, knowing about them ahead of time allows for more prudent care in the immediate aftermath, when the potential for additional impacts is higher. The rules for reconstruction, restoration, rehabilitation, and/or replacement are often different for these types of designated resources. Natural resources can have beneficial functions that reduce the impacts of natural hazards, such as wetlands and riparian habitat, which help absorb and attenuate floodwaters. Losses to economic assets (e.g., major employers or primary economic sectors) could have severe impacts on a community and its ability to recover from disaster.
The City of Forest Hills is located within the USGS 7.5 Quadrangle. The following endangered species have been identified within this quadrangle:
Vertebrate Animals - Bachman’s Sparrow; Streamside Salamander; Bewick’s Wren; and Barn Owl
Invertebrate Animals -Nashville Crayfish
Vascular Plants - Tennessee Milk-vetch; Davis’ Sedge; American Chestnut; Leafy Prairie-clover; Goldenseal; American Water-pennywort; Butternut; Duck River Bladderpod; Michigan Lily; Shaggy False Gromwell; Thicket Parsley; White Water- buttercup; and Water Stitchwort
The National Register of Historic Places identifies the following historic properties in the City of Forest Hills:
Mrs. Edward B. Craig House; Dubuisson--Neuhoff House; Guildfor Dudley Sr. and Anne Dallas House; Houston Jr., P.D. House; Thomas P. Kennedy Jr. House; Richard E. Martin House; Dr. Cobb Pilcher House.
After a disaster, economic vitality is the engine that drives recovery. Every community has a specific set of economic drivers, which are important to understand when planning ahead to reduce disaster impacts to the economy. When major employers and sectors suffer severe
The City of Forest Hills, Tennessee Chapter 3-54 Multi-Hazard Mitigation Plan DRAFT
losses and/or are unable to return to normal operations, impacts ripple throughout the community.
3.3.3 Social Vulnerability
Certain demographic and housing characteristics may amplify or reduce overall vulnerability to hazards. These characteristics, such as age, race/ethnicity, income levels, gender, building quality, public infrastructure, all contribute to social vulnerability. A Social Vulnerability Index compiled by the Hazards and Vulnerability Research Institute in the Department of Geography at the University of South Carolina measures the social vulnerability of U.S. counties to environmental hazards for the purpose of examining the differences in social vulnerability among counties. Based on national data sources, primarily the 2000 census, it synthesizes 42 socioeconomic and built environment variables that research literature suggests contribute to reduction in a community’s ability to prepare for, respond to, and recover from hazards (i.e., social vulnerability). Eleven composite factors were identified that differentiate counties according to their relative level of social vulnerability: personal wealth, age, density of the built environment, single-sector economic dependence, housing stock and tenancy, race (African American and Asian), ethnicity (Hispanic and Native American), occupation, and infrastructure dependence.
Figure 3.21 City of Forest Hills Critical Facilities
Source: http://webra.cas.sc.edu/hvri/products/sovi.aspx
The City of Forest Hills, Tennessee Chapter 3-55 Multi-Hazard Mitigation Plan DRAFT
Compared to other areas of the nation, the City of Forest Hills’ social vulnerability is medium. To better understand the characteristics behind this ranking, the HMPC researched information from the 2000 census on four factors of social vulnerability: gender, age, language spoken in home, and wealth/poverty. One characteristic of social vulnerability is differential access to resources and greater susceptibility to hazards. All factors considered here are related to this characteristic. Table 3.16 displays these variables and compares them to the same variables for Colorado and the United States. These factors of social vulnerability hold many implications for disaster response and recovery and are important considerations when identifying and prioritizing mitigation actions and overall goals and objectives of the plan.
Table 3.16 Measures of Social Vulnerability
Community United States Tennessee Davidson County City of Forest Hills Total Population 308,745,538 6,346,105 626,681 4,812 (2010) Total Housing Units 129,969,653 2,780,857 285,197 2,141 (2009) % Female 50.7 51.3 51.5 47.7 (2009) % Under Age 18 24.3 23.7 22.2 not available (2009) % Over Age 65 12.9 13.4 10.8 14.7 (2009) % Speak Language Other than English in Home 19.6 5.9 13.8 4.6 (2005-2009) % Individuals Below Poverty Level 14.3 17.2 17.1 2.9 (2009) Median Value ($), Owner-Occupied Homes $185,400 $128,500 $159,000 $606,600 (2005-2009) Source: US Census Bureau.gov
The City of Forest Hills, Tennessee Chapter 3-56 Multi-Hazard Mitigation Plan DRAFT
3.3.4 Estimating Potential Losses by Hazard
This section describes overall vulnerability and identifies structures and estimates potential losses to buildings, infrastructure, and critical facilities located in identified hazard areas. This assessment was limited to the hazards that were considered moderate or high in planning significance, based on HMPC input and the hazard profiles. Hazards ranked of low significance due to a lack of notable past damage or very low probabilities are not included in the vulnerability assessment. These include the following:
Dam Failure Drought Earthquake Land subsidence and sinkholes Wildfires
This assessment is also limited by the data available for the high or moderate ranked hazards. The methods of analysis vary by hazard type and data available. Many of the identified hazards, particularly weather related hazards, affect the entire planning area, and specific hazards areas cannot be mapped geographically. For these hazards, which include extreme temperatures, thunderstorms, tornadoes, and winter storms, vulnerability is mainly discussed in qualitative terms because data on potential losses to structures is not available. Geographic hazard areas can be mapped for the following identified hazards: flood and landslide.
Flood
Existing Development
The best available data for flooding in City of Forest Hills was generated by HAZUS-MH MR5, FEMA’s software program for estimating potential losses from disasters. The current flood insurance rate map for the City was completed in 2001.
HAZUS-MH was used to generate a 100- and 500-year floodplain for major rivers and creeks in the City. The software produces a flood polygon and flood-depth grid that represents the base flood. While not as accurate as official flood maps, such as digital flood insurance rate maps, these floodplain boundaries are for use in GIS-based loss estimation. Once the floodplain was generated, the software’s census-block data was used to estimate population displacement and potential losses to the City.
HAZUS-MH provides reports on the number of buildings impacted, estimates of the building repair costs, and the associated loss of building contents and business inventory. Building damage can result in additional losses to a community as a whole by restricting a building’s ability to function properly. Income loss data accounts for business interruption and rental income losses as well as the resources associated with damage repair and job and housing losses. These losses are calculated by HAZUS-MH using a methodology based on the building damage estimates. Flood damage is directly related to the depth of the potential flooding. For
The City of Forest Hills, Tennessee Chapter 3-57 Multi-Hazard Mitigation Plan DRAFT
example, a two-foot flood generally results in about 20 percent damage to the structure (which translates to 20 percent of the structure’s replacement value).
Table 3.17 Estimated Displaced Persons and Impacted Buildings
Displaced Impacted Jurisdiction Persons Buildings
Forest Hills 287 16
Source: HAZUS-MH MR5
Table 3.18. Estimated Building Losses
Rental Cost Cost Lost Income Building Contents Inventory Relocation Wages Loss Total Loss Percent Jurisdiction Damage ($) Damage ($) Loss ($) Loss ($) ($) ($) ($) of Total
Forest Hills 4,415 3,220 50 1 4 0 7,691 1.3
Source: HAZUS-MH MR5 *Dollar amounts in thousands
Default HAZUS-MH data was used to develop the loss estimates. Thus, the potential losses derived from HAZUS-MH, the best available data, may contain some inaccuracies. The building valuations used in HAZUS-MH MR3 are based on RSMeans 2006 and commercial data is based on Dun & Bradstreet 2006. There could be errors and inadequacies associated with the hydrologic and hydraulic modeling of the HAZUS-MH model. The damaged building counts generated by HAZUS-MH are susceptible to rounding errors and are likely the weakest output of the model due to the use of census blocks for analysis.
Critical Facilities at Risk Critical facilities data from the HMPC, the National Bridge Inventory, and the National Inventory of Dams (the latter two from HAZUS-MH) was used along with the floodplain generated by HAZUS-MH to identify critical facilities in the floodplain. There is only one critical facility in the City of Forest Hills floodplain, Percy Priest Elementary School, as identified in Figure 3.22. Additionally, all buildings which touch the 100- and 500-year floodplains are also identified; this includes the 16 structures damaged by the 100-year event.
The City of Forest Hills, Tennessee Chapter 3-58 Multi-Hazard Mitigation Plan DRAFT
Figure 3.22. Critical Facilities in the 100-Year Floodplain in Forest Hills
The City of Forest Hills, Tennessee Chapter 3-59 Multi-Hazard Mitigation Plan DRAFT
National Flood Insurance Program As provided by the NFIP Coordinator for the State, there are currently 47 flood insurance policies in force and there have been a total of 10 previous flood insurance claims.
Landslide
Existing Development
In order to determine the vulnerability of Forest Hills to landslides, percent slopes were determined in a GIS environment utilizing digital elevation models (DEMs). DEMs represent topography either by a series of regular grid points with assigned elevation values or as a triangulated irregular network (TIN) where each point is stored by its coordinates and the surface is represented by triangular facets.
Percent slope is computed as a change in elevation (∆z) over a certain distance (∆s) where ∆z is the difference in elevation between the given grid point and the lowest grid point in its neighborhood, and ∆s is the distance between those two points.
Once percent slopes were determined throughout the planning area, those parcels which encompassed a slope of 30-percent or greater were identified (see Figure 3.23). Note, a 30- percent slope is equivalent to a 16-degree slope. Of the 63 identified landslide incidents occurring due to the May 2010 event, 51 occurred on parcels with slopes greater than 30- percent.
A total of 489 parcels encompass a slope of 30-percent or greater. Estimated building loss was assumed to be the total value of the structure.
Table 3.19 Estimated Building Losses
Cost Number of Percent Building Percent of Jurisdiction Parcels of Total Damage ($) Total
Forest Hills 489 22 214,858,800 36.7
Source: Parcel Data from Metropolitan Nashville-Davidson County Tax Assessor
Road closures are a primary impact of landslide events in Forest Hills. Landslides that close roads affect the economic well-being of the community.
The City of Forest Hills, Tennessee Chapter 3-60 Multi-Hazard Mitigation Plan DRAFT
Figure 3.23. Parcels with Slopes Greater than 30-percent
The City of Forest Hills, Tennessee Chapter 3-61 Multi-Hazard Mitigation Plan DRAFT
3.3.5 Future Land Use and Development
The risk of flooding to future development should be minimized by the floodplain management programs of the City, if properly enforced. Risk could be further reduced by strengthening floodplain ordinances and floodplain management programs beyond minimum NFIP requirements.
The risk of landslides to future development should be minimized by the hillside protection ordinance of the City. Incorporating the steep slope areas into the development review process could prevent siting of structures and infrastructure in identified hazard areas. For those locations with identified previous incidents of landslides, corrective and preventative measures include slope reduction or reestablishment of the former natural slope; interception of subsurface water; and diversion of surface water before it enters the material.
3.4 Summary of Key Issues
The Forest Hills Risk Assessment revealed a number of problem areas to be addressed in the mitigation strategy. These key findings are summarized in the following list:
The majority of past disaster declarations, as well as past damages, have been related to flooding, severe storms, and tornadoes.
Sensitive natural areas and species primarily occur along streams and drainages.
Identified facilities in the floodplain include one school, Percy Priest Elementary, and residential structures.
Identified facilities in the steep slope areas are residential structures. No critical facilities were identified in these areas. For the purpose of the local hazard mitigation plan, a slope of 30-percent or greater was identified. For the hillside protection plan, the determining slope for inclusion should be further researched.
Hazard events that cause road closures, such as landslides, affect the community.
There is one high hazard dam, Radnor Lake, which is located directly upstream of the community. Although no dam failures have occurred in the past, the inundation mapping of a dam failure should be obtained from TDEC.
There is not a large percentage of population that does not speak English at home; therefore, outreach to non-English speaking populations is not a primary focus in the City of Forest Hills.
Winter weather events create problems with utilities and roadway safety.
The City of Forest Hills, Tennessee Chapter 3-62 Multi-Hazard Mitigation Plan DRAFT
4 MITIGATION STRATEGY
44 CFR Requirement 201.6(c)(3): The plan shall include a mitigation strategy that provides the jurisdiction’s blueprint for reducing the potential losses identified in the risk assessment, based on existing authorities, policies, programs and resources, and its ability to expand on and improve these existing tools.
This section presents the mitigation strategy developed by the Hazard Mitigation Planning Committee (HMPC) based on the risk assessment. The mitigation strategy was developed through a collaborative group process and consists of goals, objectives, and mitigation actions. The HMPC used the following definitions, which are based upon those found in FEMA publication 386-3, Developing the Mitigation Plan (2002):
Goals are general guidelines that explain what you want to achieve. Goals are defined before considering how to accomplish them so that they are not dependent on the means of achievement. They are usually long-term, broad, policy-type statements. Objectives define strategies or implementation steps to attain the identified goals and are specific and measurable. Mitigation Actions are specific actions that help achieve goals and objectives.
4.1 Goals and Objectives
The HMPC developed goals and objectives to provide direction for reducing hazard-related losses in the City of Forest Hills. These were based upon the results of the risk assessment and a review of goals and objectives from other state and local plans, specifically, the State of Tennessee Hazard Mitigation Plan and the City of Forest Hills Comprehensive Plan. This review was to ensure that this plan’s mitigation strategy was integrated with existing plans and policies.
Through a brainstorming process at their second and third meeting, the HMPC identified a variety of possible goals and then came to a consensus on four main ones. Following the development of goals, the HMPC identified specific objectives to achieve each goal. Goals and objectives are listed below, but are not prioritized:
Goal 1: Reduce the risk of natural hazards to the people, property, and environment of the City of Forest Hills
Reduce the vulnerability of future development Protect and preserve the community character and natural resources Maintain and improve the flood mitigation program
The City of Forest Hills, Tennessee 4.1 Multi-Hazard Mitigation Plan DRAFT Goal 2: Improve the capabilities of the City of Forest Hills to mitigate natural hazards and reduce exposure
Improve the quality and availability of hazard-related data and geographic information to better understand vulnerability Strengthen communication and coordination between Forest Hills and surrounding communities, public agencies, businesses, and non-profit organizations
Goal 3: Promote effective training and educational opportunities regarding natural hazards and risk
Improve public understanding of hazards and risk Identify and develop needed training and education for targeted audiences
Goal 4: Implement the mitigation actions identified in the Local Hazard Mitigation Plan
Prioritize mitigation funding and activities based upon the most likely and damaging future events Incorporate mitigation into existing and future policies in the community
The City of Forest Hills, Tennessee 4.2 Multi-Hazard Mitigation Plan DRAFT 4.2 Identification and Analysis of Mitigation Actions
44 CFR Requirement §201.6(c)(3)(ii): The mitigation strategy shall include a section that identifies and analyzes a comprehensive range of specific mitigation actions and projects being considered to reduce the effects of each hazard, with particular emphasis on new and existing buildings and infrastructure.
To identify and analyze potential mitigation actions to achieve the mitigation goals, the HMPC discussed the key issues that emerged in the Risk Assessment at their third meeting. Each hazard identified in Section 3.1 was evaluated. Only those hazards with an overall vulnerability ranking of moderate or high were determined to be a priority hazard and were considered further in the development of hazard-specific mitigation measures. The following are Forest Hills’s priority hazards:
Severe Weather - Extreme Temperatures - Thunderstorms (high winds, hail, lightning) - Tornadoes - Winter Storms Dam Failure Drought/Wildfire Flood Landslides
The HMPC eliminated other hazards from further consideration in the development of mitigation actions because the risk of a hazard event in the City is unlikely, the vulnerability of the City to the hazard is low, or capabilities are already in place to mitigate its negative impacts. It is important to note that many of the final mitigation actions are multi-hazard actions designed to reduce potential losses from all types of hazard events.
At their third meeting, the HMPC was provided the following list of categories of mitigation actions, which originated from the National Flood Insurance Program’s Community Rating System, as well as definitions and examples for each category:
1) Prevention: Administrative or regulatory actions or processes that influence the way land and buildings are developed and built 2) Property protection: Actions that involve the modification of existing buildings or structures to protect them from a hazard or remove them from the hazard area 3) Structural: Actions that involve the construction of structures to reduce the impact of hazard 4) Natural resource protection: Actions that, in addition to minimizing hazard losses, also preserve or restore the functions of natural systems 5) Emergency services: Actions that protect people and property during and immediately after a disaster or hazard event
The City of Forest Hills, Tennessee 4.3 Multi-Hazard Mitigation Plan DRAFT 6) Public education and awareness: Actions to inform and educate citizens, elected officials, and property owners about the hazards and potential ways to mitigation them
The HMPC then analyzed a list of potential structural and nonstructural mitigation alternatives, which were organized by hazard and based upon the risk assessment, existing capabilities, and plan goals and objectives. Through a facilitated planning process, each committee member developed ideas for mitigation actions based upon these alternatives and their own ideas. Duplicate ideas were condensed to a refined list of mitigation actions that were written on index cards and categorized by mitigation action type.
Some alternatives identified did not make it to this refined list because they were determined by the HMPC to not be politically, technically, or financially feasible or because no champion for the action was present in the group. However, these ideas are still captured in Appendix C and may be readdressed if funding opportunities change or during the next plan update process.
4.3 Implementation of Mitigation Actions
44 CFR Requirement §201.6(c)(3)(ii): The mitigation strategy shall include an action strategy describing how the actions identified in paragraph (c)(2)(ii) will be prioritized, implemented, and administered by the local jurisdiction. Prioritization shall include a special emphasis on the extent to which benefits are maximized according to a cost benefits review of the proposed projects and their associated costs.
To prioritize the mitigation actions, the HMPC voted on the identified actions. For this “multi- voting” approach all of the mitigation actions under consideration were presented on index cards. Each member of the HMPC was then given 5 votes, or colored dots, to apply to the mitigation actions he felt most important. The number of dots on each index card was added up. Based upon the number of dots, or votes, they received, the mitigation actions were assigned a priority of high, medium, or low.
This process of identification and analysis of mitigation options allowed the HMPC to come City of Forest Hills, Mitigation Actions to consensus and to prioritize recommended mitigation actions. Emphasis was placed on the importance of a cost-benefit analysis in determining project priority; however, this was not a quantitative analysis. The Disaster Mitigation Act regulations state that benefit- cost review is the primary method by which mitigation projects should be prioritized. Recognizing the federal regulatory requirement to prioritize by benefit-cost and the need for any publicly funded project to be cost-effective, the HMPC decided to pursue implementation
The City of Forest Hills, Tennessee 4.4 Multi-Hazard Mitigation Plan DRAFT according to when and where damage occurs, available funding, political will, local priority, and priorities identified in the State of Tennessee Hazard Mitigation Plan. Cost-effectiveness will be considered in additional detail when seeking FEMA mitigation grant funding for eligible projects identified in this plan.
Tables 4.1 summarizes identified actions and provides information on the hazards addressed and plan goals achieved. The individual action items, as recommended and prioritized by the HMPC, are presented in order of priority. Each action item includes the background information, ideas for implementation, responsible office, potential funding, cost estimates, benefits, and timeline for each identified action.
The City of Forest Hills, Tennessee 4.5 Multi-Hazard Mitigation Plan DRAFT
Table 4.1. Mitigation Action Matrix
HMPC Goals Hazards Action Priority Addressed Addressed
Severe 1. Publish information on the availability of severe weather alerts through new and High Goals 1, 2, 3 Weather; innovative ways, such as text messaging, email, and mobile-enabled webpages. Flood
2. Develop a comprehensive public education program for the natural hazards and High Goals 1, 3 Multi-Hazard risk identified in the Local Hazard Mitigation Plan.
Winter 3. Publish information on streets currently designated as priority for snow removal High Goals 1, 3 Storms; and evacuation. Landslides
4. Coordinate with Metropolitan-Nashville Davidson County Office of Emergency Management (OEM) for inclusion of the City of Forest Hills in the Emergency High Goals 1, 2 Multi-Hazard Operations Plan.
5. Identify and prioritize, as applicable, capital improvement projects to address High Goals 1, 4 Flood stormwater infrastructure deficiencies and/or problem areas.
6. Develop sheltering plan for severe weather hazards through coordination with High Goals 1, 2 Multi-Hazard OEM and Red Cross, including capability of new City Hall to serve as shelter.
7. Update vulnerability assessment for breach of Radnor Lake dam based upon the inundation profile in the USACE 1989 study and updated topography and parcel Medium Goals 1, 2 Dam Failure information for the City of Forest Hills.
8. Identify areas not currently within storm siren coverage and potential locations Severe Medium Goals,1, 2 for additional sirens. Weather
The City of Forest Hills, Tennessee 4.6 Multi-Hazard Mitigation Plan DRAFT 9. Strengthen communication with neighboring communities. Medium Goals 1, 2 Multi-Hazard
10. Implement contingency communications plan. Low Goals 1, 2 Multi-Hazard
Severe 11. Promote safe rooms for individual residences. Low Goals 1, 3 Weather
12. Implement and enforce hillside protection component of zoning ordinance. Low Goals 1, 4 Landslides
13. Participate in the floodplain map modernization process with Metropolitan Low Goals 1, 2, 4 Flood Nashville-Davidson County.
14. Distribute National Flood Insurance Program information. Low Goals 1, 3 Flood
15. Coordinate annual meetings of the City of Forest Hills Hazard Mitigation Planning Committee to monitor, evaluate, and update the multi-hazard mitigation Low Goal 4 Multi-Hazard plan.
The City of Forest Hills, Tennessee 4.7 Multi-Hazard Mitigation Plan DRAFT
Recommended Action Items
Mitigation Action 1 – Severe Weather Alerts
Publish information on the availability of severe weather alerts through new and Project Description: innovative ways, such as text messaging, email, and mobile-enabled webpages.
Local Prioritization: High
Primary Hazard : Severe Weather; Flood
While the timing of some hazard events may leave little time for residents to respond, some hazards, such as the onset of severe weather, can be Issue/Background: addressed through the development of a direct public alert system or publication of free email, text, sms alerts services.
Research existing weather alert services which provide text or email weather alerts for specific areas. Plan for Implementation and Publish alert information to City website Administration: Additionally, enhance efforts to promote awareness and use of the NOAA Weather Alert receivers and warning program by all citizens.
Lead Agency: City Manager Metropolitan Nashville-Davidson County – Office of Emergency Management; Partners: Web Designer Funding Description: Forest Hills existing operating budget
Total Cost: Staff time for research and upload of information to City website Benefits: Life safety, property protection (Losses Avoided) Completion Date: Within 1 year
The City of Forest Hills, Tennessee 4.8 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 2 – Comprehensive Public Education Program
Develop a comprehensive public education program for the natural hazards and Project Description: risk identified in the Local Hazard Mitigation Plan.
Local Prioritization: High
Primary Hazard : Multi-Hazard
Forest Hills is subject to several natural hazards, each of which poses a different degree of risk and associated vulnerability. Some hazards have a combination of attributes, including a high likelihood of occurrence, a specific location that is likely to be affected, and proven approaches that can reduce the impact; therefore the HMPC has recommended that specific actions be taken in Issue/Background: regard to these hazards.
For other hazards, where either the likelihood of occurrence is very low, the area of likely impact cannot be specified, or there is very little that can be done to reduce the impacts of the hazard, the HMPC has determined that the best approach would be to raise public awareness.
An educational program for the community should include information describing historical events and losses, the likelihood of future occurrences, the range of possible impacts, appropriate actions citizens can take to save lives and minimize property damage, and resources for additional information. Any information provided through this effort should be accurate, specific, timely, and consistent with current and accepted local emergency management procedures.
Compile mitigation brochures from the following organizations: FEMA; TEMA; American Red Cross; Metropolitan Nashville-Davidson County – Office of Emergency Management
Plan for Distribute these materials to City of Forest Hills residents. Materials can Implementation and be distributed at city council meetings, commission meetings, city hall, Administration: and other appropriate venues.
Use a variety of information outlets including local news media, distribution of brochures and leaflets, water bill inserts, websites, and public service announcements. Current brochures and flyers should be put on display in office buildings, libraries, and other public places. In addition, information should be linked to billing e-payments.
Investigate opportunities to cooperate with Realtor Associations in preparing the public information program strategy. Possibilities include developing a real estate agents’ brochure or a process whereby real estate agents disclose hazard information to potential property purchasers, for example through the listing services.
The City of Forest Hills, Tennessee 4.9 Multi-Hazard Mitigation Plan DRAFT Continue all public information activities currently taking place. Review effectiveness and revise accordingly.
Lead Agency: City Manager
Partners: Metropolitan Nashville-Davidson County – Office of Emergency Management Forest Hills existing operating budget; 5% state set aside from future HMGP Funding Description: funding and PDM funds $5-$20,000 depending upon printing and mailing costs, level of volunteer Total Cost: participation, and scope and frequency of events. Benefits: Life safety, property protection (Losses Avoided) Completion Date: Annually
Mitigation Action 3 – Priority Streets
Publish information on streets currently designated as priority for snow removal Project Description: and evacuation.
Local Prioritization: High
Primary Hazard : Winter Storms; Landslides
Following a hazard event access to impacted areas of the city is very important. Issue/Background: As a result, to avoid isolation, Forest Hills has evacuation and priority snow removal routes in an effort to be resilient to natural hazards.
Evacuation and priority snow routes are established. Plan for Publication of routes to City’s website. Implementation and Administration: An outreach program that educates the public on evacuation routes taking into account neighborhood specific needs.
Lead Agency: City Manager
Partners: Planning Commission; Web Designer
Funding Description: Forest Hills existing operating budget
Total Cost: Staff Time Benefits: Loss of life and infrastructure damage (Losses Avoided) Completion Date: Within 1 year
The City of Forest Hills, Tennessee 4.10 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 4 – Emergency Operations Plan Coordination
Coordinate with Metropolitan-Nashville Davidson County Office of Emergency Project Description: Management (OEM) for inclusion of the City of Forest Hills in the Emergency Operations Plan
Local Prioritization: High
Primary Hazard : Multi-Hazard
Assistance agreements between agencies, organizations, and jurisdictions provide a mechanism to quickly obtain emergency assistance in the form of Issue/Background: personnel, equipment, materials, and other associated services. The primary objective is to facilitate rapid, short-term deployment of emergency support prior to, during, and after an incident. Plan for Develop formal agreements with external partners (e.g. non-profit organizations, Implementation and cities, and state agencies) to work together on risk reduction efforts in the City. Administration: Lead Agency: City Manager
Partners: Metropolitan Nashville-Davidson County – Office of Emergency Management
Funding Description: Forest Hills existing operating budget
Total Cost: Staff Time Benefits: Loss of life and infrastructure damage (Losses Avoided) Completion Date: Within 1 year
The City of Forest Hills, Tennessee 4.11 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 5 – Stormwater Infrastructure
Identify and prioritize, as applicable, capital improvement projects to address Project Description: stormwater infrastructure deficiencies and/or problem areas.
Local Prioritization: High
Primary Hazard : Flood
Increased urbanization within the City of Forest Hills causes changes to the topography, ground cover, and stormwater management system within the community. These changes effect on the environment, primarily through the Issue/Background: subsequent increase in quantity of stormwater runoff. In some areas, the combination of increased runoff and the location of property near a stream causes frequent flooding.
Identify locations and assess the need to construct and/or replace Plan for Implementation existing storm water infrastructure throughout the City of Forest Hills and Administration: Obtain funding and implement storm water/drainage improvements
Lead Agency: City Manager
Partners: City Engineer
Funding Description: Forest Hills existing operating budget
Total Cost: Cost of stormwater infrastructure investigation - $5,000 - $25,000 Benefits: Protection of property and infrastructure (Losses Avoided) Completion Date: Within 3 to 5 years
The City of Forest Hills, Tennessee 4.12 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 6 – Sheltering Plan
Develop sheltering plan for severe weather hazards through coordination with Project Description: OEM and Red Cross, including capability of new City Hall to serve as shelter.
Local Prioritization: High
Primary Hazard : Multi-Hazard
In the event of a natural hazard emergency, residents as well as vulnerable populations, such as the very young and the elderly may need to seek shelter. Issue/Background: The elderly and the very young are particularly vulnerable because they may require special accommodations. Developing and equipping an emergency shelter is important to accommodate the citizens of Forest Hills.
Develop a list of emergency shelter needs for residents and vulnerable populations. Identify emergency shelters in the city and inventory the existing equipment and supplies in each shelter. Pre-position supplies at each city-owned public shelter, either within the structure or in a Plan for shipping container. Implementation and Administration: To ensure a reliable power supply, provide an emergency generator and fuel tank at each public shelter.
Coordinate efforts with the American Red Cross.
Lead Agency: City Manager Metropolitan Nashville-Davidson County – Office of Emergency Management Partners: American Red Cross Funding Description: HMGP; PDM; staff time; Forest Hills existing operating budget
Total Cost: Staff time; Construction of FEMA 361 Shelter Benefits: Loss of life (Losses Avoided) Completion Date: Within 5 years
The City of Forest Hills, Tennessee 4.13 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 7 – Update to Dam Break Vulnerability Assessment
Update vulnerability assessment for breach of Radnor Lake dam based upon Project Description: the inundation profile in the USACE 1989 study and updated topography and parcel information for the City of Forest Hills.
Local Prioritization: High
Primary Hazard : Dam Failure
Developing risk assessment maps that show areas at risk for dam break can improve land use planning efforts; response/evacuation efforts; and can prevent future damage to property. Data obtained from TDEC Safe Dams Program Issue/Background: included inundation mapping from a study conducted by the USACE in 1989. Updating this information with current topography and parcel information will better assist the City in identifying vulnerable areas. Plan for Provide City Engineer with inundation information from USACE study. Review Implementation and inundation mapping and determine if vulnerability within community has Administration: increased due to increased development within the inundation area. Lead Agency: City Manager
Partners: City Engineer; TDEC Safe Dams
Funding Description: Forest Hills existing operating budget
Total Cost: Cost of additional vulnerability assessment - $2,000 - $10,000 Benefits: Life safety, property protection (Losses Avoided) Completion Date: Within 3 to 5 years
The City of Forest Hills, Tennessee 4.14 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 8 – Storm Siren Coverage
Identify areas not currently within storm siren coverage and potential locations Project Description: for additional sirens.
Local Prioritization: High
Primary Hazard : Severe Weather
The HMPC identified the need to improve warning systems in the city. These warning systems are necessary to let residents know of impending natural disasters or other emergency situations. Improving the City of Forest Hills’ Issue/Background: warning systems should involve identifying the current warning systems, identifying areas where needs are not being met, and developing strategies for improving those systems or addressing those needs.
Conduct an evaluation of the warning system to determine needs that are not being met.
Consult with the HMPC to develop recommendations for improvements. Plan for Implementation and Coordinate with the Metropolitan Nashville-Davidson County Office of Administration: Emergency Management warning systems.
Conduct public outreach efforts to make the public aware of warning systems in the community.
Lead Agency: City Manager
Partners: Metropolitan Nashville-Davidson County Office of Emergency Management Forest Hills existing operating budget; Homeland Security Grant; National Funding Description: Weather Service Grants Total Cost: Staff time; cost of sirens Benefits: Life safety, property protection; improved warning, increased lead time on (Losses Avoided) warning systems and mitigation efforts, reduced losses Completion Date: Within 3 to 5 years
The City of Forest Hills, Tennessee 4.15 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 9 – Communication with neighboring communities
Project Description: Strengthen communication with neighboring communities
Local Prioritization: High
Primary Hazard : Multi-Hazard
Strengthening the communication among neighboring communities in regards to hazard mitigation and emergency management will allow the communities to Issue/Background: gain a vested interest in implementation and establish relationships prior to emergency situations.
Identify departments or organizations within neighboring communities with which collaboration would be beneficial for furthering hazard mitigation and emergency response. Plan for Implementation and Administration: Develop a regular meeting schedule to discuss current issues and concerns with hazard mitigation implementation and emergency response.
Lead Agency: City Manager Metropolitan Nashville-Davidson County – Office of Emergency Management Partners: Neighboring communities of Belle Meade, Oak Hill and Nashville-Davidson County; Williamson County Funding Description: Forest Hills existing operating budget
Total Cost: Staff Time Benefits: Improved warning, increased lead time on warning systems and mitigation (Losses Avoided) efforts, reduced losses Completion Date: Within 1 year
The City of Forest Hills, Tennessee 4.16 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 10 – Contingency Communications Plan
Project Description: Implement contingency communications plan
Local Prioritization: Medium
Primary Hazard : Multi-Hazard
An emergency / disaster communications plan which provides intra- and inter- agency operability between the City of Forrest Hills and other relevant agencies, Issue/Background: in order to provide contingency communications if necessary during a casualty event where normal communications methods are failing.
Identify amateur radio spotters who would be willing to provide communications in an emergency, and provide a reliable communications link to the EOC or to report local conditions.
Plan for Implementation Recruit amateur radio operators for above task. and Administration: Purchase Public Safety radio equipment
Obtain a Public Safety Radio License under the Metropolitan Nashville Government by filling out the form and obtaining the proper callsigns and talk- group frequencies.
Lead Agency: City Manager
Partners: HMPC Member Steve Waterman
Funding Description: Forest Hills existing operating budget
Total Cost: Staff Time and Public Safety Radio Equipment (approximately $400 to $5000) Benefits: Life safety, property protection (Losses Avoided) Completion Date: Within 1 year
The City of Forest Hills, Tennessee 4.17 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 11 – Safe Rooms
Project Description: Promote safe rooms for individual residences
Local Prioritization: Medium
Primary Hazard : Severe Weather
Tornadoes and severe weather in Forest Hills pose a serious threat to buildings and their occupants. Residential structures may be built to existing code requirements, but that does not mean the structure can withstand winds from Issue/Background: extreme events such as tornadoes. The purpose of a safe room is to provide a space where individual homeowners can seek a refuge that provides a high level of protection.
Publish safe room and vendor information on City’s website from vendors certified by the National Storm Shelter Association.
Plan for Implementation and Administration: Publish FEMA design standards for safe rooms on City’s website.
Coordinate with TEMA on safe room initiatives as set forth by the state, if and when applicable.
Lead Agency: City Manager Metropolitan Nashville-Davidson County – Office of Emergency Management; Partners: Web Designer Funding Description: Forest Hills existing operating budget; HMGP; PDM
Total Cost Staff Time for materials and information publication Benefits: Life safety (Losses Avoided) Completion Date: Within 3 to 5 years
The City of Forest Hills, Tennessee 4.18 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 12 – Hillside Protection
Project Description: Implement and enforce hillside protection component of zoning ordinance
Local Prioritization: Medium
Primary Hazard : Landslides
Forest Hills has steep slope areas throughout the community. Roadway corridors lie under most of these steep slopes and generally above the slopes Issue/Background: are residential land uses. Steeps slopes are susceptible to landslide, caused by severe weather with a high likelihood of occurring.
Areas with slopes greater than 15% have been identified.
Through the Zoning Ordinance, develop setback requirements for structures in steep slopes areas identified through the Hillside Protection Program.
Plan for Implementation Educate residents where steep slopes are a major concern, including and Administration: information about longer-term mitigation, as well as short-term preparedness.
Publish map of hillside protection areas to City’s website
Include possible slope stabilization measures to dewater, drain, armor, or reinforce slopes (I.e. with shotcrete or gabions).
Lead Agency: Planning Commission
Partners: City Engineer; Web Designer
Funding Description: Forest Hills existing operating budget
Total Cost: Staff Time Benefits: Life safety, property protection (Losses Avoided) Completion Date: Ongoing
The City of Forest Hills, Tennessee 4.19 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 13 – Flood Map Modernization
Participate in the floodplain map modernization process with Metropolitan Project Description: Nashville-Davidson County
Local Prioritization: Medium
Primary Hazard : Flood
Metropolitan Nashville-Davidson County is currently involved with the FEMA map modernization process. The USACE Nashville District is currently completing 180 miles of new detailed study in Davidson County. Those models Issue/Background: are scheduled to be completed in December 2011. With the new models, FEMA will prepare the updated Flood Insurance Rate Maps (FIRMS) with preliminary issuance anticipated for summer 2012. Through this process, floodplains in Forest Hills will be updated along Otter Creek and extended along Richland Creek.
Plan for Implementation Forest Hills will attend meetings related to the map modernization process and and Administration: will review and comment, if appropriate, on preliminary DFIRMs when available.
Lead Agency: City Engineer
Partners: City of Forest Hills, Tennessee ECD Flood Map Modernization Program, FEMA
Funding Description: City of Forest Hills
Total Cost Staff time
Updated and more accurate floodplain maps Benefits: Development of floodplain management program (Losses Avoided) Reduced risk to people and property from flooding
Completion Date: Summer/Fall 2012
The City of Forest Hills, Tennessee 4.20 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 14 – NFIP Information
Project Description: Distribute National Flood Insurance Program information
Local Prioritization: Medium
Primary Hazard : Flood
Having information placed at City Hall and in local libraries will help to inform Issue/Background: Forest Hills citizens of the requirements for floodplain development and the availability of flood insurance.
Plan for Implementation Copies of publications produced by FEMA for the NFIP would be gathered and and Administration: reviewed. Copies of the materials could be collected and distributed to local libraries and City Hall
Lead Agency: Forest Hills City Manager
Partners: Nashville Public Library; City of Forest Hills; FEMA NFIP
Funding Description: Forest Hills Operating budget
Total Cost: 16 hours at $75 per hour = $1,200
Benefits: Improve access to information regarding the floodplain development program by (Losses Avoided) public and real estate agents, insurance agents, homeowners, and business owners.
Completion Date: In coordination with Action Item 13, Fall 2012
The City of Forest Hills, Tennessee 4.21 Multi-Hazard Mitigation Plan DRAFT Mitigation Action 15 – HMPC Annual Meeting
Coordinate annual meetings of the City of Forest Hills Hazard Mitigation Project Description: Planning Committee to monitor, evaluate, and update the multi-hazard mitigation plan
Local Prioritization: Medium
Primary Hazard : Multi-Hazard
Holding annual meetings to evaluate the plan’s progress and effectiveness will help to keep the plan action-oriented and will assist in a smoother five-year Issue/Background: update process. This action will also implement the process for monitoring, evaluating, and updating the plan described in Chapter 5 Plan Implementation and Maintenance.
The City of Forest Hills City Manager will coordinate these meetings. The first Plan for Implementation annual meeting will be held in September 2012 to evaluate progress and, if and Administration: necessary, update the hazard mitigation plan. The meeting will be held at the Forest Hills City Hall. Meeting agendas will incorporate the process described in Chapter 5 Plan Implementation and Maintenance.
Lead Agency: Forest Hills City Manager
Partners: All agencies involved in initial planning efforts and the Hazard Mitigation Planning Committee
Funding Description: Forest Hills existing operating budget
Total Cost: Minimal
Benefits: Keep plan current and accurate (Losses Avoided) Improve communication among Board of Commissioners, Planning Commission, and Zoning and Appeals
Completion Date: Annually, first meeting September 2012
The City of Forest Hills, Tennessee 4.22 Multi-Hazard Mitigation Plan DRAFT 5 PLAN MAINTENANCE PROCESS
This chapter provides an overview of the overall strategy for plan maintenance and outlines the method and schedule for monitoring, updating, and evaluating the plan. The chapter also discusses incorporating the plan into existing planning mechanisms and how to address continued public involvement.
5.1 Monitoring, Evaluating, and Updating the Plan
44 CFR Requirement 201.6(c)(4): The plan maintenance process shall include a section describing the method and schedule of monitoring, evaluating, and updating the mitigation plan within a five- year cycle.
5.1.1 Hazard Mitigation Planning Committee
With adoption of this plan, the HMPC will be tasked with plan monitoring, evaluation, and maintenance of the plan. The City of Forest Hills agrees to:
Meet annually and after a disaster event to monitor and evaluate the implementation of the plan; Act as a forum for hazard mitigation issues; Disseminate hazard mitigation ideas and activities to all participants; Pursue the implementation of high priority, low- or no-cost recommended actions; Maintain vigilant monitoring of multi-objective, cost-share, and other funding opportunities to help the community implement the plan’s recommended actions for which no current funding exists; Monitor and assist in implementation and update of this plan; Keep the concept of mitigation in the forefront of community decision making by identifying plan recommendations when other community goals, plans, and activities overlap, influence, or directly affect increased community vulnerability to disasters; Report on plan progress and recommended changes to the City of Forest Hills Board of Commissioners; and Inform and solicit input from the public.
The HMPC is an advisory body and will not have any powers over City staff. Its primary duty is to see the plan successfully carried out and to report to the community governing boards and the public on the status of plan implementation and mitigation opportunities. Other duties include reviewing and promoting mitigation proposals, hearing stakeholder concerns about hazard mitigation, passing concerns on to appropriate entities, and posting relevant information on the City website.
The City of Forest Hills, Tennessee DRAFT 5.1 Multi-Hazard Mitigation Plan DRAFT 5.1.2 Plan Maintenance Schedule
The HMPC agrees to meet annually and after a hazard event to monitor progress and update the mitigation strategy. A five-year written update of the plan will be submitted to the Tennessee Department of Emergency Management and FEMA Region IV per Requirement §201.6(c)(4)(i) of the Disaster Mitigation Act of 2000, unless disaster or other circumstances (e.g., changing regulations) require a change to this schedule.
5.1.3 Plan Maintenance Process
Evaluation of progress can be achieved by monitoring changes in vulnerabilities identified in the plan. Changes in vulnerability can be identified by noting:
Decreased vulnerability as a result of implementing recommended actions, Increased vulnerability as a result of failed or ineffective mitigation actions, and/or Increased vulnerability as a result of new development (and/or annexation).
Updates to this plan will:
Consider changes in vulnerability due to action implementation, Document success stories where mitigation efforts have proven effective, Document areas where mitigation actions were not effective, Document any new hazards that may arise or were previously overlooked, Incorporate new data or studies on hazards and risks, Incorporate new capabilities or changes in capabilities, Incorporate growth and development-related changes to inventories, and Incorporate new action recommendations or changes in action prioritization.
In order to best evaluate any changes in vulnerability as a result of plan implementation, the City of Forest Hills will follow the following process:
A representative from the responsible office identified in each mitigation action will be responsible for tracking and reporting on an annual basis to the jurisdictional lead on action status and provide input on whether the action as implemented meets the defined objectives and is likely to be successful in reducing vulnerabilities. If the action does not meet identified objectives, the jurisdictional lead will determine what additional measures may be implemented, and an assigned individual will be responsible for defining action scope, implementing the action, monitoring success of the action, and making any required modifications to the plan.
Changes will be made to the plan to accommodate for actions that have failed or are not considered feasible after a review of their consistency with established criteria, time frame, community priorities, and/or funding resources. Actions that were not ranked high but were
The City of Forest Hills, Tennessee DRAFT 5.2 Multi-Hazard Mitigation Plan DRAFT identified as potential mitigation activities will be reviewed as well during the monitoring and update of this plan to determine feasibility of future implementation. Updating of the plan will be by written changes and submissions and as approved by the City of Forest Hills Board of Commissioners.
5.2 Incorporation into Existing Planning Mechanisms
44 CFR Requirement §201.6(c)(4)(ii):[The plan shall include a] process by which local governments incorporate the requirements of the mitigation plan into other planning mechanisms such as comprehensive or capital improvement plans, when appropriate.
Where possible, plan participants will use existing plans and/or programs to implement hazard mitigation actions. Based on the capability assessment, the City of Forest Hills will continue to plan and implement programs to reduce losses to life and property from hazards. This plan builds upon the momentum developed through previous and related planning efforts and mitigation programs and recommends implementing actions, where possible, through the following plans:
The City of Forest Hills Comprehensive Plan The City of Forest Hills Stormwater Ordinance The City of Forest Hills Zoning Ordinance The City of Forest Hills Subdivision Regulations Metro Nashville-Davidson County Flood Insurance Study Metro Nashville-Davidson County Multi-Hazard Mitigation Plan Metro Nashville-Davidson County Emergency Operations Plan State of Tennessee Multi-Hazard Mitigation Plan
HMPC members involved in updating these existing planning mechanisms will be responsible for integrating the findings and actions of the mitigation plan, as appropriate. The HMPC is also responsible for monitoring this integration and incorporating the appropriate information into the five-year update of the multi-hazard mitigation plan.
5.3 Continued Public Involvement
44 CFR Requirement §201.6(c)(4)(iii): [The plan maintenance process shall include a] discussion on how the community will continue public participation in the plan maintenance process.
The update process provides an opportunity to publicize success stories from the plan’s implementation and seek additional public comment. Information will be posted in local newspapers and on the City website following the annual review of the mitigation plan. A public hearing(s) to receive public comment on plan maintenance and updating will be held during the update period. When the HMPC reconvenes for the update, they will coordinate with all stakeholders participating in the planning process, including those who joined the HMPC after the initial effort, to update and revise the plan. Public notice will be posted and public
The City of Forest Hills, Tennessee DRAFT 5.3 Multi-Hazard Mitigation Plan DRAFT participation will be invited, at a minimum, through available website postings and press releases to the local media outlets, primarily newspapers.
The City of Forest Hills, Tennessee DRAFT 5.4 Multi-Hazard Mitigation Plan DRAFT