SECTION 6 VULNERABILITY ASSESSMENT

Transcription

1 SECTION 6 VULNERABILITY ASSESSMENT This section identifies and quantifies the vulnerability of the MEMA District 1 Region to the significant hazards identified in the previous sections (Hazard Identification and Profiles). It consists of the following subsections: 6.1 Overview 6.2 Methodology 6.3 Explanation of Data Sources 6.4 Asset Inventory 6.5 Vulnerability Assessment Results 6.6 Conclusions on Hazard Vulnerability 44 CFR Requirement 44 CFR Part 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. The description shall include an overall summary of each hazard and its impact on the community. The plan should describe vulnerability in terms of: (A) The types and numbers of existing and future buildings, infrastructure, and critical facilities located in the identified hazard areas; (B) An estimate of the potential losses to vulnerable structures identified in paragraph (c)(2)(ii)(a) of this section and a description of the methodology used to prepare the estimate; (C) 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. 6.1 OVERVIEW This section builds upon the information provided in Section 4: Hazard Identification and Section 5: Hazard Profiles by identifying and characterizing an inventory of assets in the MEMA District 1 Region. In addition, the potential impact and expected amount of damages caused to these assets by each identified hazard event is assessed. The primary objective of the vulnerability assessment is to quantify exposure and the potential loss estimates for each hazard. In doing so, the MEMA District 1 counties and their participating jurisdictions may better understand their unique risks to identified hazards and be better prepared to evaluate and prioritize specific hazard mitigation actions. This section begins with an explanation of the methodology applied to complete the vulnerability assessment, followed by a summary description of the asset inventory as compiled for the MEMA District 1 Region. The remainder of this section focuses on the results of the assessment conducted. 6.2 METHODOLOGY This vulnerability assessment was conducted using three distinct methodologies: (1) A stochastic risk assessment; (2) a geographic information system (GIS)-based analysis; and (3) a risk modeling software analysis. Each approach provides estimates for the potential impact of hazards by using a common, systematic framework for evaluation, including historical occurrence information provided in the Hazard 6:1

2 Identification and Analysis sections. A brief description of the three different approaches is provided on the following pages Stochastic Risk Assessment The stochastic risk assessment methodology was applied to analyze hazards of concern that were outside the scope of hazard risk models and the GIS-based risk assessment. This includes hazards that do not have geographically-definable boundaries and are therefore excluded from spatial analysis through GIS. A stochastic risk methodology was used for the following hazards: Dam and Levee Failure Drought Erosion Extreme Heat Hailstorm Land Subsidence/Sinkhole Lightning Severe Thunderstorm/High Wind Tornado Winter Storm and Freeze Many of the hazards listed above are considered atmospheric and have the potential to affect all buildings and all populations. For many of these hazards listed above, no additional analysis was performed. When possible, annualized loss estimates were determined using the best available data on historical losses from sources including NOAA s National Climatic Data Center records, MEMA District 1 Region county hazard mitigation plans, and local knowledge. Annualized loss is the estimated long-term weighted average value of losses to property in any single year in a specified geographic area (i.e., municipality or county). Annualized loss estimates were generated by totaling the amount of property damage over the period of time for which records were available, and calculating the average annual loss. Given the standard weighting analysis, losses can be readily compared across hazards providing an objective approach for evaluating mitigation alternatives. For the erosion, dam and levee failure 1, and land subsidence/sinkhole hazards no data with historical property damages was available. Therefore, annualized losses for these hazards are identified as negligible, though it should be noted that this does not indicate that future losses will not occur. Drought, extreme heat, hailstorm, lightning, severe thunderstorm/high wind, tornado, and winter storm and freeze have the potential to impact the entire MEMA District 1 Region. The results for these hazards are found near the end of this section in Table GIS-Based Analysis Other hazards have specified geographic boundaries that permit additional using Geographic Information Systems (GIS). These hazards include: 1 As noted in Section 5: Hazard Profiles, Dam failure could be catastrophic to areas in the inundation area. Due to a lack of data, no additional analysis was performed. Further, local MEMA District 1 officials indicate that separate dam failure plans have been completed for some dams in their counties to identify risk and response measures. As additional data becomes available, more indepth analysis may be conducted. 6:2

3 Flood Landslide Wildfire The objective of the GIS-based analysis was to determine the estimated vulnerability of critical facilities and populations for the identified hazards in the MEMA District 1 Region using best available geospatial data. Digital data was collected from local, regional, state, and national sources for hazards and buildings. Communities in the MEMA District 1 Region generally did not have readily available geospatial parcel or building footprint data, though where it was available, it was used in the analysis. Despite this lack of data, the HMC wanted to have some estimate of potential building and dollar losses, so 2010 Census block data was extracted from Hazus MH that included building counts and dollar values of property in the region. Additionally, geo-referenced point locations for identified assets (critical facilities and infrastructure, special populations, etc.) were identified via Hazus MH 3.1 and used in this vulnerability analysis. ESRI ArcGIS 10.3 was used to assess hazard vulnerability utilizing digital hazard data, as well as local building and exposure data described above. Using these data layers, hazard vulnerability can be quantified by estimating the number and dollar value of census blocks determined to be located in identified hazard areas. However, it should be noted that this method likely overestimates the number and value of property at risk. To estimate vulnerable populations in hazard areas, digital Census 2010 data by census tract was obtained. This was intersected with hazard areas to determine exposed population counts. The results of the analysis provided an estimate of the number of people and critical facilities, as well as the value of buildings determined to be potentially at risk to those hazards with delineable geographic hazard boundaries Risk Modeling Software Analysis A risk modeling software was used for the following hazards: Earthquake Hurricane and Tropical Storm There are several models that exist to model hazards. Hazus-MH was used in this vulnerability assessment to address the aforementioned hazards. HAZUS-MH Hazus-MH ( Hazus ) is a standardized loss estimation software program developed by FEMA. It is built upon an integrated GIS platform to conduct analysis at a regional level (i.e., not on a structure-by-structure basis). The Hazus risk assessment methodology is parametric, in that distinct hazard and inventory parameters (e.g., wind speed and building types) can be modeled using the 6:3

4 software to determine the impact (i.e., damages and losses) on the built environment. The MEMA District 1 Regional Risk Assessment utilized Hazus-MH to produce hazard damage loss estimations for hazards for the planning area. At the time this analysis was completed, Hazus-MH 3.1 was used to estimate potential damages from hurricane winds earthquake hazards using Hazus-MH methodology. Although the program can also model losses for flood and storm surge, it was not used in this Risk Assessment. Figure 6.1 illustrates the conceptual model of the Hazus-MH methodology. FIGURE 6.1: CONCEPTUAL MODEL OF HAZUS-MH METHODOLOGY Hazus-MH is capable of providing a variety of loss estimation results. In order to be consistent with other hazard assessments, annualized losses are presented when possible. Loss estimates provided in this vulnerability assessment are based on best available data and methodologies. The results are an approximation of risk. These estimates should be used to understand relative risk from hazards and potential losses. Uncertainties are inherent in any loss estimation methodology, arising in part from incomplete scientific knowledge concerning natural hazards and their effects on the built environment. Uncertainties also result from approximations and simplifications that 6:4

5 are necessary for a comprehensive analysis (e.g., incomplete inventories, non-specific locations, demographics, or economic parameters). All conclusions are presented in Conclusions on Hazard Vulnerability at the end of this section. 6.3 EXPLANATION OF DATA SOURCES FLOOD FEMA Digital Flood Rate Insurance Maps (DFIRM) flood data was used to determine flood vulnerability. DFIRM data can be used in ArcGIS for mapping purposes, and they identify several features including floodplain boundaries and base flood elevations. Identified areas on the DFIRM represent some features of a Flood Insurance Rate Maps including the 100-year flood areas (1.0-percent annual chance flood), and the 500-year flood areas (0.2-percent annual chance flood). For the vulnerability assessment, local improved property data and critical facilities were overlaid on the 1.0-percent annual chance floodplain (ACF) areas for counties that had digital parcel data available. No 0.2-percent annual chance floodplain areas were identified in any of the county DFIRMS. It should be noted that such an analysis does not account for building elevation. LANDSLIDE The USGS Landslide Susceptibility Index was used to determine vulnerability to landslides. This index classifies different zones or areas of risk to landslides based on two evaluation criteria: incidence and susceptibility. Incidence is based on the previous reports of landslides incidents and susceptibility is based on the potential for future landslides in terms of soils types and other locational factors. Each zone is scored has High, Medium, or Low on both evaluation criteria, resulting in 6 different categorizations of landslide risk. For the vulnerability assessment, census block data and critical facilities were overlaid on these incidence/susceptibility areas. WILDFIRE The data used to determine vulnerability to wildfire in the MEMA District 1 Region is based on GIS data called the Southern Wildfire Risk Assessment (SWRA). This data is available on the Southern Wildfire Risk Assessment website and can be downloaded and imported into ArcGIS. A specific layer, known as Wildland Urban Interface Risk Index (WUIRI) was used to determine vulnerability of people and property. The WUIRI is presented on a scale of 0 to -9. It combines data on housing density with the data on the impact and likelihood of a wildfire occurring in a specific area. The primary purpose of the data is to highlight areas of concern that may be conducive to mitigation actions. Due to assumptions made, it is not true probability. However, it does provide a comparison of risk throughout the region. EARTHQUAKE Hazus-MH 3.1 (as described above) was used to assess earthquake vulnerability. A level 1, probabilistic scenario to estimate average annualized loss was utilized. In this scenario, several return periods (events of varying intensities) are run to determine annualized loss. Default Hazus earthquake damage functions and methodology were used to determine the probability of damage. Results are calculated at the 2010 U.S. Census tract level in Hazus and presented at the county level. 6:5

6 HURRICANE AND TROPICAL STORM WIND Hazus-MH 3.1 (as described above) was used to assess wind vulnerability. For the hurricane wind analysis, a probabilistic scenario was created to estimate the annualized loss damage in the MEMA District 1 Region. Default Hazus wind speed data, damage functions, and methodology were used in to determine the probability of damage for 100-, 500-, and 1,000-year frequency events (also known as a return period) in the scenario. Results are calculated in Hazus at the 2010 U.S. Census tract level and presented at the county level. 6.4 ASSET INVENTORY An inventory of geo-referenced assets within the MEMA District 1 counties and jurisdictions was compiled in order to identify and characterize those properties potentially at risk to the identified hazards. 2 By understanding the type and number of assets that exist and where they are located in relation to known hazard areas, the relative risk and vulnerability for such assets can be assessed. Under this assessment, two categories of physical assets were created and then further assessed through GIS analysis. Additionally, social assets are addressed to determine population at risk to the identified hazards. These are presented below in Section Physical and Improved Assets The two categories of physical assets consist of: 1. Improved Property: Unfortunately, building footprint and parcel data was not available for most of the participating areas. Therefore the definition of improved property includes all improved properties in the MEMA District 1 Region according to building data extracted from Hazus MH 3.1. It should be noted that this data produced less accurate information concerning the number of buildings at risk than parcel data because the Hazus data was aggregated at a much larger geographic area, the census block level. Where local parcel data was available, it was used to improve analysis. Hazus inventory data provides an estimate of the number of buildings in the study region. The economic exposure is also presented to be referenced with any Hazus-related results. 2. Critical Facilities: Critical facilities vary by jurisdiction. For this Vulnerability Assessment, facilities were initially collected from Hazus-MH which includes fire stations, police station, medical care facilities, schools, emergency operation centers, government buildings, shelters, water/utility infrastructure, and other facilities. This data was then reviewed by local officials who used local knowledge to supplement the Hazus data. It should be noted that this listing is not all-inclusive for assets located in the region, but it is anticipated that it will be expanded during future plan updates as more geo-referenced data becomes available for use in GIS analysis. The following tables provide a detailed listing of the geo-referenced assets that have been identified for inclusion in the vulnerability assessment for the MEMA District 1 Region. 2 While potentially not all-inclusive for MEMA District 1, georeferenced assets include those assets for which specific location data is readily available for connecting the asset to a specific geographic location for purposes of GIS analysis. 6:6

7 Table 6.1 lists the estimated number of improved properties and the total value of improvements for participating areas of the MEMA District 1 Region (study area of vulnerability assessment). Because digital parcel data was not available for most communities, data obtained from Hazus-MH 3.1 inventory was utilized to complete the analysis. Grenada County provided parcel data for its jurisdictional area. TABLE 6.1: IMPROVED PROPERTY IN THE MEMA DISTRICT 1 REGION Location Counts of Improved Property Total Value of Improvements Coahoma County 10,085 $2,115,582,000 Clarksdale 6,741 $1,461,759,000 Coahoma (town) 131 $19,739,000 Friars Point 440 $89,931,000 Jonestown 446 $63,072,000 Lula 146 $38,153,000 Lyon 249 $70,246,000 Unincorporated Area 2,181 $442,928,000 DeSoto County 58,878 $16,384,913,000 Hernando 6,576 $1,876,565,000 Horn Lake 8,470 $2,097,067,000 Olive Branch 12,779 $3,953,300,000 Southaven 19,594 $5,566,173,000 Walls 892 $227,950,000 Unincorporated Area 10,567 $2,663,858,000 Grenada County 16,265 $468,263,937 Grenada (city) 7,259 $243,355,688 Unincorporated Area 9,006 $224,908,249 Panola County 15,241 $2,611,950,000 Batesville 3,602 $937,897,000 Como 661 $106,541,000 Courtland 397 $49,625,000 Crenshaw 489 $63,160,000 Pope 241 $32,847,000 Sardis 1,081 $233,173,000 Unincorporated Area 9,851 $1,421,880,000 Quitman County 3,561 $622,982,000 Crowder 365 $49,246,000 Falcon 61 $7,583,000 Lambert 628 $90,657,000 Marks 1,010 $235,212,000 Sledge 210 $36,427,000 Unincorporated Area 1,287 $203,857,000 Tallahatchie County 5,718 $864,002,000 Charleston 1,302 $200,806,000 Glendora 65 $7,119,000 Sumner 201 $38,080,000 Tutwiler 458 $101,044,000 6:7

8 Location Counts of Improved Property Total Value of Improvements Webb 294 $39,089,000 Unincorporated Area 3,398 $477,864,000 Tate County 11,307 $2,227,227,000 Coldwater 827 $156,835,000 Senatobia 3,119 $829,954,000 Unincorporated Area 7,361 $1,240,438,000 Tunica County 3,997 $956,560,000 Tunica (town) 709 $196,669,000 Unincorporated Area 3,288 $759,891,000 Yalobusha County 6,521 $1,076,236,000 Coffeeville 772 $119,450,000 Oakland 360 $101,606,000 Water Valley 1,885 $381,424,000 Unincorporated Area 3,504 $473,756,000 MEMA DISTRICT 1 REGIONAL TOTAL 131,573 $27,327,715,937 Source: Hazus-MH 3.1, Local County GIS Departments Table 6.2 lists the fire stations, police stations, medical care facilities, emergency operations centers (EOCs), schools, shelters, government buildings, water/utility infrastructure, and other facilities located in the MEMA District 1 Region according to Hazus-MH Version 3.1 data that was reviewed and updated by local officials. In addition, Figure 6.2 shows the locations of critical facilities in the MEMA District 1 Region. Table 6.12, at the end of this section, shows a complete list of the critical facilities by name, as well as the hazards that affect each facility. As noted previously, this list is not all-inclusive and only includes information provided through Hazus which was updated, as best as possible, with local knowledge. Location TABLE 6.2: CRITICAL FACILITY INVENTORY IN THE MEMA DISTRICT 1 REGION Fire Stations Police Stations Medical Care EOC Schools Gov t* Water/ Utility* Shelter* Other* Coahoma County Clarksdale Coahoma (town) Friars Point Jonestown Lula Lyon Unincorporated Area DeSoto County Hernando Horn Lake Olive Branch Southaven Walls :8

9 Location Fire Stations Police Stations Medical Care EOC Schools Gov t* Water/ Utility* Shelter* Other* Unincorporated Area Grenada County Grenada (city) Unincorporated Area Panola County Batesville Como Courtland Crenshaw Pope Sardis Unincorporated Area Quitman County Crowder Falcon Lambert Marks Sledge Unincorporated Area Tallahatchie County Charleston Glendora Sumner Tutwiler Webb Unincorporated Area Tate County Coldwater Senatobia Unincorporated Area Tunica County Tunica (town) Unincorporated Area Yalobusha County Coffeeville Oakland Water Valley Unincorporated Area MEMA DISTRICT 1 REGIONAL TOTAL *All counties were not able to attain information on these facility types, however, this should not imply that these counties do not have any of these types of facilities. Instead, it should be noted that as this information is collected, it will be incorporated in future updates of the plan. Source: Hazus-MH 3.1, Local Officials 6:9

10 FIGURE 6.2: CRITICAL FACILITY LOCATIONS IN THE MEMA DISTRICT 1 REGION Source: Hazus-MH 3.1, Local Officials Social Vulnerability In addition to identifying those assets potentially at risk to identified hazards, it is important to identify and assess those particular segments of the resident population in the MEMA District 1 Region that are potentially at risk to these hazards. Table 6.3 lists the population by jurisdiction according to U.S. Census 2010 population estimates. The total population in the MEMA District 1 Region according to Census data was 319,959 persons. Additional population estimates are presented in Section 3: Community Profile. TABLE 6.3: TOTAL POPULATION IN THE MEMA DISTRICT 1 REGION Location Total 2010 Population Coahoma County 26,151 DeSoto County 161,252 Grenada County 21,906 Panola County 34,707 6:10

11 Location Total 2010 Population Quitman County 8,223 Tallahatchie County 15,378 Tate County 28,886 Tunica County 10,778 Yalobusha County 12,678 MEMA DISTRICT 1 REGION TOTAL 319,959 Source: United States Census Bureau, 2010 Census In addition, Figure 6.3 illustrates the population density per square kilometer by census tract as it was reported by the U.S. Census Bureau in As can be seen in the figure, the population is spread out with concentrations in large municipal areas such as the Memphis suburbs in the north of the region as well as several other high density municipal areas such as Clarksdale and Grenada. FIGURE 6.3: POPULATION DENSITY IN THE MEMA DISTRICT 1 REGION Source: United States Census Bureau, 2010 Census 6:11

12 6.4.3 Development Trends and Changes in Vulnerability Since the previous county hazard mitigation plans were approved, the MEMA District 1 Region has experienced limited growth and development. Table 6.4 shows the number of building units constructed since 2010 according to the U.S. Census American Community Survey. TABLE 6.4: BUILDING COUNTS FOR THE MEMA DISTRICT 1 REGION Location Total Housing Units (2014) Units Built 2010 or later % Building Stock Built Post-2010 Coahoma County 10, % Clarksdale 7, % Coahoma (town) % Friars Point % Jonestown % Lula % Lyon % Unincorporated Area 2, % DeSoto County 62,703 1, % Hernando 5, % Horn Lake 9, % Olive Branch 13, % Southaven 19, % Walls % Unincorporated Area 14, % Grenada County 10, % Grenada (city) 6, % Unincorporated Area 4, % Panola County 14, % Batesville 3, % Como % Courtland % Crenshaw % Pope % Sardis % Unincorporated Area 9, % Quitman County 3, % Crowder % Falcon % Lambert % Marks % Sledge % Unincorporated Area 1, % Tallahatchie County 5, % Charleston % Glendora % 6:12

13 Location Total Housing Units (2014) Units Built 2010 or later % Building Stock Built Post-2010 Sumner % Tutwiler % Webb % Unincorporated Area 3, % Tate County 11, % Coldwater % Senatobia 3, % Unincorporated Area 7, % Tunica County 4, % Tunica (town) % Unincorporated Area 4, % Yalobusha County 6, % Coffeeville % Oakland % Water Valley 1, % Unincorporated Area 4, % MEMA DISTRICT 1 REGIONAL TOTAL 129,694 1, % Source: United States Census Bureau, American Community Survey 5-Year Estimates Table 6.5 shows population growth estimates for the region from 2010 to 2014 based on the U.S. Census American Community Survey. Location TABLE 6.5: POPULATION GROWTH FOR THE MEMA DISTRICT 1 REGION Population Estimates % Change Coahoma County 26,681 26,376 26,099 25,813 25, % Clarksdale 18,276 18,092 17,906 17,725 17, % Coahoma (town) % Friars Point 1, % Jonestown 1,381 1,426 1,304 1,327 1, % Lula % Lyon % Unincorporated Area 4,797 4,565 4,808 4,796 4, % DeSoto County 154, , , , , % Hernando 13,253 13,679 14,117 14,437 14, % Horn Lake 25,495 25,901 26,120 26,350 26, % Olive Branch 31,910 32,796 33,484 34,050 34, % Southaven 46,743 48,005 48,981 49,728 50, % Walls , % Unincorporated Area 36,730 37,405 38,109 38,496 39, % Grenada County 22,619 22,302 21,886 21,754 21, % Grenada (city) 13,415 13,270 13,121 13,028 12, % 6:13

14 Location Population Estimates % Change Unincorporated Area 9,204 9,032 8,765 8,726 8, % Panola County 34,782 34,763 34,675 34,558 34, % Batesville 7,486 7,477 7,457 7,455 7, % Como 1,309 1,391 1,406 1,563 1, % Courtland % Crenshaw 1,093 1,132 1,118 1, % Pope % Sardis 1,485 1,786 1,810 1,778 2, % Unincorporated Area 22,761 22,169 22,066 21,860 21, % Quitman County 8,551 8,378 8,171 8,028 7, % Crowder % Falcon % Lambert 1,615 1,506 1,415 1,153 1, % Marks 2,325 2,010 1,967 1,820 1, % Sledge % Unincorporated Area 3,213 3,450 3,394 3,618 3, % Tallahatchie County 15,270 15,279 15,262 15,231 15, % Charleston 2,065 2,323 2,233 2,171 1, % Glendora % Sumner % Tutwiler 3,161 3,321 3,432 3,505 3, % Webb % Unincorporated Area 9,133 8,633 8,745 8,728 9, % Tate County 28,198 28,447 28,580 28,625 28, % Coldwater 1,735 1,771 1,778 1,379 1, % Senatobia 7,958 8,040 8,071 8,099 8, % Unincorporated Area 18,505 18,636 18,731 19,147 19, % Tunica County 10,817 10,802 10,716 10,660 10, % Tunica (town) 1,229 1,292 1,296 1,329 1, % Unincorporated Area 9,588 9,510 9,420 9,331 9, % Yalobusha County 12,869 12,787 12,647 12,554 12, % Coffeeville 943 1,071 1,055 1, % Oakland % Water Valley 3,485 3,444 3,399 3,393 3, % Unincorporated Area 7,910 7,780 7,628 7,449 7, % MEMA DISTRICT 1 REGIONAL TOTAL 314, , , , , % Source: United States Census Bureau, , , , , and American Community Survey 5-Year Estimates Based on the data above, there has been a relatively low rate of residential development and population growth in the region since 2010, and many jurisdictions have actually experienced population declines. However, it is notable that communities in DeSoto County and the Memphis suburbs seemed to experience a slightly higher rate of growth and development compared to the rest of the region, resulting in an increased number of people and structures that are vulnerable to the potential impacts 6:14

15 of the identified hazards. Additionally, an overall trend in the region seems to be that there is a considerably higher rate of population growth in some communities within a county, while others have experienced significant reductions in population. As a result, there are now greater numbers of people exposed to the identified hazards in some areas while there are fewer in other areas. Therefore, development and population growth have impacted the region s vulnerability since the previous local hazard mitigation plans were approved and there has been a slight increase in the overall vulnerability as well as a significant increase in certain areas and communities. It is also important to note that as development increases in the future, greater populations and more structures and infrastructure will be exposed to potential hazards if development occurs in the floodplains, landside susceptibility areas, or high wildfire risk areas. 6.5 VULNERABILITY ASSESSMENT RESULTS As noted earlier, only hazards with a specific geographic boundary, available modeling tool, or sufficient historical data allow for further analysis in this section. Those results are presented here. All other hazards are assumed to impact the entire planning region (drought, extreme heat, hailstorm, lightning, severe thunderstorm/high wind, tornado, and winter storm) or, due to lack of data, analysis would not lead to credible results (dam and levee failure, erosion, and land subsidence/sinkhole). The total region exposure, and thus risk to these hazards, was presented in Table 6.1. The hazards to be further analyzed in this section include: flood, landslide, wildfire, earthquake, and hurricane and tropical storm winds. The annualized loss estimate for all hazards is presented at the end of this section in Table Flood Historical evidence indicates that the MEMA District 1 Region is susceptible to flood events. A total of 211 flood events have been reported by the National Climatic Data Center resulting in over $1 billion (2016 dollars) in property damage as well as 7 fatalities and 10 injuries. On an annualized level, these damages amounted to $74,951,864 for the MEMA District 1 Region. In order to assess flood risk, a GIS-based analysis was used to estimate exposure to flood events using Digital Flood Insurance Rate Map (DFIRM) data in combination with improved property records for each of the MEMA District 1 Counties (with the exception of Quitman, Panola, and Tallahatchie). The determination of value at-risk (exposure) was calculated using GIS analysis by summing the values for improved properties that were located within an identified floodplain. Due to a lack of digital parcel data in most counties, it was determined that an analysis using the inventory from Hazus-MH 3.1 would be used, though it should be noted that the data will merely be an estimation and may not reflect actual counts or values located in the floodplain. Indeed, in almost all cases, this analysis likely overestimates the amount of property at risk. Table 6.6 presents the potential at-risk property. Both the number of parcels and the approximate value are presented. 6:15

16 TABLE 6.6: ESTIMATED EXPOSURE OF PROPERTY TO THE FLOOD HAZARD 3 Location Approx. Number of Improvements 1.0-percent ACF Approx. Improved Value Coahoma County 1,583 $358,892,000 Clarksdale 492 $135,197,000 Coahoma (town) 0 $0 Friars Point 5 $13,482,000 Jonestown 249 $36,037,000 Lula 43 $6,377,000 Lyon 31 $20,136,000 Unincorporated Area 763 $147,663,000 DeSoto County 20,172 $5,759,613,000 Hernando 2,015 $560,554,000 Horn Lake 2,233 $588,993,000 Olive Branch 2,979 $1,057,233,000 Southaven 7,031 $2,064,184,000 Walls 832 $207,184,000 Unincorporated Area 50,82 $1,281,465,000 Grenada County 5,696 $1,129,049,000 Grenada (city) 3,489 $730,442,000 Unincorporated Area 2,207 $398,607,000 Panola County* Batesville* Como* Courtland* Crenshaw* Pope* Sardis* Unincorporated Area* Quitman County* Crowder* Falcon* Lambert* Marks* Sledge* Unincorporated Area* Tallahatchie County* Charleston* Glendora* Sumner* Tutwiler* Webb* Unincorporated Area* As noted in Section 6.4, no building-specific data, such as building footprints, was available to determine buildings at risk. As a result of this data limitation, at-risk census block building counts and values of the structures were used. 6:16

17 Location Approx. Number of Improvements 1.0-percent ACF Approx. Improved Value Tate County 5,098 $1,003,140,000 Coldwater 379 $77,325,000 Senatobia 1,532 $393,601,000 Unincorporated Area 3,187 $532,214,000 Tunica County 1,769 $473,080,000 Tunica (town) 180 $40,301,000 Unincorporated Area 1,589 $432,779,000 Yalobusha County 3,301 $552,607,000 Coffeeville 582 $86,814,000 Oakland 74 $58,287,000 Water Valley 491 $116,668,000 Unincorporated Area 2,154 $290,838,000 MEMA DISTRICT 1 REGIONAL TOTAL 37,619 $9,276,381,000 *Digital Flood Maps were not available, so this analysis could not be carried out. Source: Federal Emergency Management Agency DFIRM and Hazus MH 3.1 SOCIAL VULNERABILITY Figure 6.4 is presented to gain a better understanding of at-risk population by evaluating census tract level population data against mapped floodplains. There are areas of concern in several of the municipal population centers in this region including Grenada, Clarksdale, and Horn Lake. Indeed, nearly every incorporated municipality is potentially at risk of being impacted by flooding within some areas of its jurisdictional boundary. Therefore, further investigation in these areas may be warranted. 6:17

18 FIGURE 6.4 : POPULATION DENSITY NEAR FLOODPLAINS IN THE MEMA DISTRICT 1 REGION Note: Digital flood maps were unavailable for Panola, Quitman, and Tallahatchie Counties. Source: Federal Emergency Management Agency DFIRM, United States Census 2010 CRITICAL FACILITIES The critical facility analysis revealed that there are 34 critical facilities located in the floodplain. (Please note, as previously indicated, this analysis does not consider building elevation, which may negate risk.) All of these facilities are located in the 1.0 percent annual chance flood zone, and they include 3 fire stations, 1 police station, 8 schools, 7 government buildings, 9 water/utility infrastructure, and 6 others. A list of specific critical facilities and their associated risk can be found in Table 6.12 at the end of this section. In conclusion, a flood has the potential to impact many existing and future buildings, facilities, and populations in the MEMA District 1 Region, though some areas are at a higher risk than others. All types of structures in a floodplain are at-risk, though elevated structures will have a reduced risk. Such sitespecific vulnerability determinations are outside the scope of this assessment but may be considered during future plan updates. Furthermore, areas subject to repetitive flooding should be analyzed for potential mitigation actions. 6:18

19 6.5.2 Landslide Steeper topography in some areas of the MEMA District 1 Region makes the planning area susceptible to landslides. Although no major landslide incidents have been reported in the region, it should be noted that United States Geological Survey information on historic events is not well-documented so the data may be incomplete. There may be additional historical landslide occurrences that were not reported. In order to complete the vulnerability assessment for landslides in the MEMA District 1 Region, GIS analysis was used. The potential dollar value of exposed property can be determined using the USGS Landslide Susceptibility Index (detailed in Section 5: Hazard Profiles), census block data from Hazus or county-level tax parcel data, and GIS analysis. Table 6.7 presents the potential at-risk property where available. Only a portion of the region is identified as being in a moderate incidence/high susceptibility or low incidence/high susceptibility area by the USGS landslide data. These incidence levels were used to identify areas of concern for the analysis below. TABLE 6.7: TOTAL POTENTIAL AT-RISK PARCELS FOR THE LANDSLIDE HAZARD Location Low Incidence/ High Susceptibility Area Approx. Number of Improvements Approx. Improved Value Moderate Incidence/ High Susceptibility Area Approx. Number of Improvements Approx. Improved Value Coahoma County 7,641 $1,635,636,000 0 $0 Clarksdale 5,742 $1,219,561,000 0 $0 Coahoma (town) 131 $19,739,000 0 $0 Friars Point 440 $89,931,000 0 $0 Jonestown 0 $0 0 $0 Lula 146 $38,153,000 0 $0 Lyon 34 $31,207,000 0 $0 Unincorporated Area 1,148 $237,045,000 0 $0 DeSoto County 764 $163,879,000 40,211 $10,993,925,000 Hernando 0 $0 6,576 $1,876,565,000 Horn Lake 0 $0 8,094 $1,990,575,000 Olive Branch 0 $0 2,219 $614,236,000 Southaven 0 $0 19,498 $5,540,560,000 Walls 119 $36,656, $47,740,000 Unincorporated Area 645 $127,223,000 3,649 $924,249,000 Grenada County 0 $0 2,355 $72,724,262 Grenada (city) 0 $0 81 $6,677,346 Unincorporated Area 0 $ $66,046,916 Panola County 0 $0 9,017 $1,641,389,000 Batesville 0 $0 3,424 $901,263,000 Como 0 $0 637 $103,165,000 Courtland 0 $0 397 $49,625,000 Crenshaw 0 $0 0 $0 Pope 0 $0 241 $32,847,000 Sardis 0 $0 471 $70,291,000 Unincorporated Area 0 $0 3,847 $484,198,000 6:19

20 Location Low Incidence/ High Susceptibility Area Approx. Number of Improvements Approx. Improved Value Moderate Incidence/ High Susceptibility Area Approx. Number of Improvements Approx. Improved Value Quitman County 0 $0 0 $0 Crowder 0 $0 0 $0 Falcon 0 $0 0 $0 Lambert 0 $0 0 $0 Marks 0 $0 0 $0 Sledge 0 $0 0 $0 Unincorporated Area 0 $0 0 $0 Tallahatchie County 0 $0 3,420 $484,026,000 Charleston 0 $0 1,302 $200,806,000 Glendora 0 $0 0 $0 Sumner 0 $0 0 $0 Tutwiler 0 $0 0 $0 Webb 0 $0 0 $0 Unincorporated Area 0 $0 2,118 $283,220,000 Tate County 0 $0 6,472 $1,412,244,000 Coldwater 0 $0 827 $156,835,000 Senatobia 0 $0 3,119 $829,954,000 Unincorporated Area 0 $0 2,526 $425,455,000 Tunica County 3,601 $902,085,000 0 $0 Tunica (town) 709 $196,669,000 0 $0 Unincorporated Area 2,892 $705,416,000 0 $0 Yalobusha County 0 $0 983 $199,250,000 Coffeeville 0 $0 0 $0 Oakland 0 $0 360 $101,606,000 Water Valley 0 $0 0 $0 Unincorporated Area 0 $0 623 $97,644,000 MEMA DISTRICT 1 REGIONAL TOTAL Source: United States Geological Survey and Hazus-MH ,006 $2,701,600,000 62,458 $25,797,483,262 SOCIAL VULNERABILITY Given low incidence across most of the region, it is assumed that the total population is at relatively low risk. However, some populations in the central and western part of the region are considered at slightly higher risk due to their location in areas of high susceptibility. CRITICAL FACILITIES Several critical facilities in the region are located in a low incidence/high susceptibility area. There are 110 critical facilities located in this zone. This includes 3 fire stations, 6 police stations, 25 schools, 4 medical care facilities, 12 government buildings, 6 shelters, and 54 water/utility infrastructure. In the moderate incidence/high susceptibility area, there are 126 critical facilities including: 2 emergency 6:20

21 operations centers, 34 fire stations, 14 police stations, 52 schools, 4 medical care facilities, 7 government buildings, 8 water/utility infrastructure, and 5 others. A list of specific critical facilities and their associated risk can be found in Table 6.12 at the end of this section. In conclusion, a landslide has the potential to impact all existing and future buildings, facilities, and populations in the MEMA District 1 Region, though areas in the western part of the region and within a central strip running north-south through the region are at a higher risk than others due to a variety of factors. Specific vulnerabilities for MEMA District 1 assets will be greatly dependent on their individual design and the mitigation measures in place where appropriate. Such site-specific vulnerability determinations are outside the scope of this assessment but will be considered during future plan updates if data becomes available Wildfire Although historical evidence indicates that the MEMA District 1 Region is susceptible to wildfire events, there are few reports which include information on historic dollar losses. Therefore, it is difficult to calculate a reliable annualized loss figure. Annualized loss is considered negligible though it should be noted that a single event could result in significant damages throughout the region. To estimate exposure to wildfire, building data was obtained from Hazus-MH 3.1 for most counties which includes information that has been aggregated at the census block level and which has been deemed useful for analyzing wildfire vulnerability. However, it should be noted that the accuracy of Hazus data is somewhat lower than that of parcel data. For the critical facility analysis, areas of concern were intersected with critical facility locations. Figure 6.5 shows the Wildland Urban Interface Risk Index (WUIRI) data, which is a data layer that shows a rating of the potential impact of a wildfire on people and their homes. The key input, Wildland Urban Interface (WUI), reflects housing density (houses per acre) consistent with Federal Register National standards. The location of people living in the WUI and rural areas is key information for defining potential wildfire impacts to people and homes. Initially provided as raster data, it was converted to a polygon to allow for analysis. The Wildland Urban Interface Risk Index data ranges from 0 to -9 with lower values being most severe (as noted previously, this is only a measure of relative risk). Figure 6.6 shows the areas of analysis where any grid cell is less than -5. Areas with a value below -5 were chosen to be displayed as areas of risk because this showed the upper echelon of the scale and the areas at highest risk. Table 6.8 shows the results of the analysis. 6:21

22 FIGURE 6.5: WUI RISK INDEX AREAS IN THE MEMA DISTRICT 1 REGION Source: Southern Wildfire Risk Assessment Data 6:22

23 FIGURE 6.6: WILDFIRE RISK AREAS IN THE MEMA DISTRICT 1 REGION Source: Southern Wildfire Risk Assessment Data TABLE 6.8: EXPOSURE OF IMPROVED PROPERTY 4 TO WILDFIRE RISK AREAS Location Approx. Number of Improvements Wildfire Risk Approx. Improved Value Coahoma County 1,904 $401,136,000 Clarksdale 1,236 $280,249,000 Coahoma (town) 0 $0 Friars Point 122 $17,575,000 Jonestown 87 $13,086,000 Lula 6 $765,000 Lyon 31 $21,335,000 Unincorporated Area 422 $68,126,000 DeSoto County 24,571 $6,754,028,000 Hernando 3,300 $918,327,000 4 Parcel/Building Footprint data was not available for most of the MEMA District 1 counties. Therefore, building counts and values were pulled from Hazus-MH at the census block level and approximate improved value was calculated. Grenada County did have parcel data available, so it was used in place of the census block data. 6:23

24 Location Approx. Number of Improvements Wildfire Risk Approx. Improved Value Horn Lake 2,158 $513,199,000 Olive Branch 4,356 $1,452,851,000 Southaven 7,380 $2,063,413,000 Walls 367 $97,620,000 Unincorporated Area 7,010 $1,708,618,000 Grenada County 2,026 $99,329,374 Grenada (city) 548 $29,896,728 Unincorporated Area 1,478 $69,432,646 Panola County 9,183 $6,754,028,000 Batesville 1,050 $298,884,000 Como 397 $59,337,000 Courtland 310 $38,740,000 Crenshaw 116 $18,886,000 Pope 165 $23,534,000 Sardis 322 $84,388,000 Unincorporated Area 7,145 $975,861,000 Quitman County 932 $172,420,000 Crowder 0 $0 Falcon 1 $126,000 Lambert 242 $40,436,000 Marks 199 $36,114,000 Sledge 11 $2,749,000 Unincorporated Area 479 $92,995,000 Tallahatchie County 2,377 $350,311,000 Charleston 363 $50,097,000 Glendora 17 $1,981,000 Sumner 44 $5,376,000 Tutwiler 287 $78,119,000 Webb 39 $6,500,000 Unincorporated Area 1,627 $208,238,000 Tate County 7,196 $1,272,677,000 Coldwater 294 $55,510,000 Senatobia 956 $227,924,000 Unincorporated Area 5,946 $989,243,000 Tunica County 982 $167,492,000 Tunica (town) 155 $31,147,000 Unincorporated Area 827 $136,345,000 Yalobusha County 4,872 $746,642,000 Coffeeville 521 $69,372,000 Oakland 141 $67,136,000 Water Valley 1,258 $212,732,000 6:24

25 Location Approx. Number of Improvements Wildfire Risk Approx. Improved Value Unincorporated Area 2,952 $397,402,000 MEMA DISTRICT 1 REGIONAL TOTAL Source: Southern Wildfire Risk Assessment and Hazus-MH ,043 $16,718,063,374 SOCIAL VULNERABILITY Given some level of susceptibility across the entire MEMA District 1 Region, it is assumed that the total population is at risk to the wildfire hazard. Determining the exact number of people in certain wildfire zones is difficult with existing data and could be misleading. CRITICAL FACILITIES The critical facility analysis revealed that there are 14 critical facilities located in wildfire areas of concern, including 5 fire stations, 3 schools, 4 government buildings, 1 water/utility infrastructure, and 1 other. It should be noted, that several factors could impact the spread of a wildfire putting all facilities at risk. A list of specific critical facilities and their associated risk can be found in Table 6.12 at the end of this section. In conclusion, a wildfire event has the potential to impact many existing and future buildings, critical facilities, and populations in the MEMA District 1 Region Earthquake As the Hazus-MH model suggests below, and historical occurrences confirm, any significant earthquake activity in the area is likely to inflict moderate damage to the planning area. Hazus-MH 3.1 estimates a total annualized loss of $8,752,000 which includes structural and non-structural damage to buildings, contents, and inventory throughout the planning area. For the earthquake hazard vulnerability assessment, a probabilistic scenario was created to estimate the average annualized loss 5 for the region on a county by county basis. The results of the analysis are generated at the census tract level within Hazus-MH and then aggregated to the county level. Since the scenario is annualized, no building counts are provided. Losses reported included losses due to structure failure, building loss, contents damage, and inventory loss. They do not include losses to business interruption, lost income, or relocation. Table 6.9 summarizes the findings with results rounded to the nearest thousand. TABLE 6.9: AVERAGE ANNUALIZED LOSS ESTIMATIONS FOR EARTHQUAKE HAZARD Location Structural Damage Non-Structural Damage Contents Damage Inventory Loss Total Annualized Loss Coahoma County $83,000 $254,000 $99,000 $4,000 $440,000 5 Annualized loss is defined by Hazus-MH as the expected value of loss in any one year. 6:25

26 Location Structural Damage Non-Structural Damage Contents Damage Inventory Loss Total Annualized Loss DeSoto County $941,000 $3,541,000 $1,397,000 $60,000 $5,939,000 Grenada County $50,000 $136,000 $57,000 $5,000 $248,000 Panola County $118,000 $351,000 $131,000 $7,000 $607,000 Quitman County $25,000 $76,000 $31,000 $2,000 $134,000 Tallahatchie County $25,000 $70,000 $24,000 $1,000 $120,000 Tate County $119,000 $392,000 $143,000 $4,000 $658,000 Tunica County $72,000 $256,000 $92,000 $3,000 $423,000 Yalobusha County $35,000 $103,000 $42,000 $3,000 $183,000 MEMA DISTRICT 1 REGION TOTAL $1,468,000 $5,179,000 $2,016,000 $89,000 $8,752,000 Source: Hazus-MH 3.1 SOCIAL VULNERABILITY It can be assumed that all existing and future populations are at risk to the earthquake hazard. CRITICAL FACILITIES The Hazus-MH probabilistic analysis did not indicate that any critical facilities would sustain measurable damage in an earthquake event. However, all critical facilities should be considered at-risk to minor to moderate damage should an event occur. A list of specific critical facilities and their associated risk can be found in Table 6.12 at the end of this section. In conclusion, an earthquake has the potential to impact all existing and future buildings, facilities, and populations in the MEMA District 1 Region. Specific vulnerabilities for these assets will be greatly dependent on their individual design and the mitigation measures in place. Such site-specific vulnerability determinations are outside the scope of this assessment but may be considered during future plan updates. The Hazus-MH scenario indicates that minimal to moderate damage is expected from an earthquake occurrence. While the MEMA District 1 Region may not experience a catastrophic earthquake (the greatest on record is a magnitude VII MMI), localized damage is possible with a moderate to larger scale occurrence Hurricane and Tropical Storm Historical evidence indicates that the MEMA District 1 Region has some risk to the hurricane and tropical storm hazard. There have been two disaster declarations due to hurricanes (Hurricane Katrina and Hurricane Isaac). Several tracks have come near or traversed through the MEMA District 1 Region, as shown and discussed in Section 5: Hazard Profiles. Hazus-MH 3.1 estimates a total annualized loss of $392,000 which includes buildings, contents, and inventory throughout the planning area. Hurricanes and tropical storms can cause damage through numerous additional hazards such as flooding, erosion, tornadoes, and high winds, thus it is difficult to estimate total potential losses from these cumulative effects. The current Hazus-MH hurricane model only analyzes hurricane winds and is not capable of modeling and estimating cumulative losses from all hazards associated with hurricanes; 6:26

27 therefore, only hurricane winds are analyzed in this section. It can be assumed that all existing and future buildings and populations are at risk to the hurricane and tropical storm hazard. Hazus-MH 3.1 was used to determine average annualized losses 6 for the region as shown below in Table Only losses to buildings, inventory, and contents are included in the results. TABLE 6.10: AVERAGE ANNUALIZED LOSS ESTIMATIONS FOR HURRICANE WIND HAZARD Location Building Damage Contents Damage Inventory Loss Total Annualized Loss Coahoma County $29,000 $6,000 $0 $35,000 DeSoto County $140,000 $17,000 $0 $157,000 Grenada County $41,000 $9,000 $0 $50,000 Panola County $38,000 $6,000 $0 $44,000 Quitman County $9,000 $1,000 $0 $10,000 Tallahatchie County $20,000 $4,000 $0 $24,000 Tate County $30,000 $6,000 $0 $36,000 Tunica County $10,000 $1,000 $0 $11,000 Yalobusha County $20,000 $6,000 $0 $26,000 MEMA DISTRICT 1 REGION TOTAL $336,000 $56,000 $0 $392,000 Source: Hazus-MH 3.1 SOCIAL VULNERABILITY Given some equal susceptibility across the entire MEMA District 1 Region, it is assumed that the total population, both current and future, is at risk to the hurricane and tropical storm hazard. CRITICAL FACILITIES Given equal vulnerability across the MEMA District 1 Region, all critical facilities are considered to be at risk. Some buildings may perform better than others in the face of such an event due to construction and age, among factors. Determining individual building response is beyond the scope of this plan. However, this plan will consider mitigation action for especially vulnerable structures and/or critical facilities to mitigate against the effects of the hurricane hazard. A list of specific critical facilities can be found in Table 6.12 at the end of this section. In conclusion, a hurricane event has the potential to impact many existing and future buildings, critical facilities, and populations in the MEMA District 1 Region. 6.6 CONCLUSIONS ON HAZARD VULNERABILITY The results of this vulnerability assessment are useful in at least three ways: Improving our understanding of the risk associated with the natural hazards in the MEMA District 1 Region through better understanding of the complexities and dynamics of risk, how 6 Annualized loss is defined by Hazus-MH as the expected value of loss in any one year. 6:27