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HomeMy WebLinkAboutLand Use Plan Update Hurricane Mitigation & Reconstruction Plan-1991 : - Hurricane -Mitigation &Reconstructions Plan December 1991 New Hanover Counfy,Planning Department; = _ = =Dexter Hayes; Director - ::Patrick Lowe, AssistaniDirector , - , ., ,_ - Staff Planners, - _ _ - Walter "Pete"Avery _ - -- -- - - WandaCoston:- - Sam Burgess Chris O'Keefe - -. - CAMA Intern _ - - JoAnne Shadroui - = Administrative Secretary - - Phoebe Saavedra .Graphics Planning Technician - Lisa laine Horne. New Hanover County Board of -Commissioners ,- I -' E L.."Matt".Mathews,-Oiacrman '- `Robert G. Greer, Vice Gtairniun - jonathaBareld - - - _ Fred Retchui " - William H.-Sutton Planning Board Members - Earnest Puskas Chairman Kenneth A.Shankl in,_ illy Chairman - -. - - -- - - - __ Robert McDonald - Wesley O: Nixon= - ; . William Gratliwoi _ - C. Richard-Boisky .- ,. . - ' Charles R. Howell_ - - - Thepaf—o'dv.aw�cv.rya,mper,dam&aca,ea mcwa - Y_ by North Crrolim Craw! Mamgemeat Program. dinwgh U . sraot provided the F�mda provided - - by the C®sW Zane Mamgemeot Ad od IM as amended. which is administered by the Office - ., -. p - dOcraa_aad&u,WRasouroeAlaoaasmeot,2JatiaoolOcmic..aadAlmosphericAdmioutnt . _ 0 101 Hurricane Mitigation & Reconstruction Plan December 1991 Wilmington - New Hanover County Land Use Plan Update K O s Preface The Coastal Area Management Act (CAMA), enacted in 1974 by the North Carolina General Assembly, requires that the 20 coastal counties of the state prepare land use plans. These plans provide a framework used to guide local leaders as they make decisions for the protection, preservation, orderly development and management of the North Carolina coastal area. The original CAMA Land Use Plan for New Hanover County was adopted in 1976. Updates to the plan are required by CAMA on five year intervals This report is part of the third plan update (1981, 1986 and 1991) performed in conjunction with the Wilmington -New Hanover Comprehensive Planning Program, initiated in 1974. InaccordancewithCAMArequireznerns, the landuseplan consists ofthefiollowing elements: 1.) Summary of data collection and analysis; 2.) Existing land use map; 3.) Policy discussion; 4.) Land classification map. This information plays an important role in the formulation of local development. regulations, such as zoning ordinances, and it provides input for growth policy decisions. These reports also provide useful data to the public and private sector in considering development proposals. '775ANVIO! FM Carolina's Hurricane History Paths TABLE OF CONTENTS I. Purpose and Scope of Study..................................................................... l II. Coastal Storm Characteristics..................................................................2 III. Coastal Storm Mitigation.........................................................................7 IV. Evacuation.............................................................................................12 V. Post Disaster Reconstruction Plan...........................................................18 VI. Initial Post Disaster Response ....................................... ................19 VII. Task Force Responsibilities....................................................................20 VIII. Conclusions and Policy Recommendations.............................................23 O U LIST OF TABLES Table 1 Saffir/Simpson Scale........................................................................................... 4 Table 2 Severity of Risk in Hazard Area.......................................................................... 5 LIST OF FIGURES Figure 1 Hurricane Strike Percentage Probability.............................................................. 3 Figure 2 Estuarine Shoreline AECs, Ocean Erodible AECs, and Inlet Hazard AECs ......... 6 Figure 3 Storm Surge Contours: Category 5...................................................................... 9 Figure 4 Storm Surge Contours: Category 4.................................................................... 10 Figure 5 North Carolina State Building Code's Basic Design Wind Velocities ................ 13 Figure 6 100 Year Floodplain, Evacuation Routes, and Emergency Shelters ...................14 Figure 7 . StormEvent Flow Chart.................................................................................... 21 L U HURRICANE MITIGATION AND RECONSTRUCTION PLAN I. PURPOSE AND SCOPE OF STUDY This plan focuses on the procedures and policies New Hanover County can utilize to mitigate the potential for the loss of life and property associated with intense hurricanes and the orderly reconstruction of public infrastructure after hurricane strikes. In supportofthese proposed policies and procedures a brief background on coastal characteristics and evacu- ation will be discussed. This plan is presented under the format required by the N.C. Coastal Management regulations (T 15:07B .0200) and includes the following items: A. Composite hazards map including data from the National Flood Insurance Program (NFIP) maps, Eastern N.C. Hurricane Evacuation Study, flood zones and other hazardous areas; — B. Existing land use inventory for those hazardous areas identified in the "Floodplain Management Plan" of New Hanover County, 1990 prepared by the New Hanover County Planning Department. C. Suggested coastal stone mitigation procedures concerning: 1. Effects of high winds, flooding and other factors; 2. Means of discouraging higher density development located in "high energy" prone areas; 3. Policies dealing with public acquisition of property in hazardous areas; and 4. Policies dealing with timely public evacuation. 1 D. Post -disaster reconstruction plan including: 1.. County emergency plan; 2. Local policies which will direct reconstruction over an extended time period; 3. Formulation of a "recovery task force" to supervise the reconstruction process; 4. Establishment of a time -table for staging and permitting repairs ofessential public services; and 5. Development of policies for repair and/or replacement of public infra- structure, including relocation to less hazardous areas. II. COASTAL STORM CHARACTERISTICS The anatomy of a tropical cyclone or hurricane resembles a large, circular column of clouds with air rotating in a counter -clockwise direction along the storm's periphery to a concentrated center of low pressure. Winds within these heat sustaining storms may exceed 200 miles per hour near the vortex, although stones of this magnitude are rare. Atlantic hurricanes typically originate as tropical waves off the west coast of Africa and in the Caribbean Sea. Hurricanes develop and mature by passing through several stages based on wind speed characteristics: Tropical depression: winds of 38 miles per hour or less Tropical storm: winds between 39 and 73 miles per hour Hurricane: winds greater than 73 miles per hour While the hurricane season extends from June through November, most recorded hurricane activity along the Carolina coast (approximately 90%) has occurred in August, September and October. New Hanover County has a 6% chance of encountering a direct strike from a hurricane. (Figure 1) Hurricanes typically have a westward forward movement of about 12-15 miles per hour. Both the direction and forward speed of the storm can vary dramatically once entering the Atlantic basin (McElyea et al, 1982). Predicting the path and travel time of a hurricane can be a difficult and complicated problem for weather forecasters due to insufficient documentation recorded from previous storms and unpredictable upper -level wind patterns that steer the storm. In recent years though, this difficulty has been reduced through the use of forecasting tools such as satellite imagery, decision arcs and the hurricane watch/warning system. These tools combined with an enhanced communication network between weather related agencies and local govern- ment officials, notably Emergency Management, has improved the ability to forecast the landfall window for storms and greatly diminish the potential for loss of life. Figure 1 located page 3. U 0 K-01 KE Percentage Probability that a Hurricane (winds exceeding- 73 mph) . or a Great Hurricane (winds exceeding 125 mph) will strike a 50-mile segment of the U.S. Coastline in any given year. 5a• 57 y. (0 • 55 too 54 53 '0 52 5 • 1 4 . .... . 4 4 46 47 45 0 CV 44 CV • 43 2 42 41 4) 40 coo 39) 39 ro :3• 38 36 37 0 37 36 3 35 0 34 • 34 13 14 17 19 • •20 C-A 7 89 10 11 12 21 31 6 22 31 511 1 14 1 16 17 18 23 30 CO 4 9 10 8 6 314 7 6 7 '19 7 69 24 — 2R 0 29 in • 2 6 2 5 23 29L 3 2 HURRICANES GREAT HURRICANES 31 Source: McElyea et al, 1982 3 Saffir/Simpson Damage Potential Scale CATAGORYI Winds of 74 to 95 miles per hour. Damage primarily to shrubbery, trees, foliage, and unanchored mobile homes. No real damage to other structures. Some damage to poorly constructed signs. And/or: storm surge 4 to 5 feet above normal. Low-lying coastal roads inundated, minor pier damage, some small craft in exposed anchorage tom from moorings. CATAGORY2 Winds of 96 to 110 miles per hour. Considerable damage to shrubbery and tree foliage; some trees blown down. Major damage to exposed mobile homes. Extensive damage to poorly constructed signs. Some damage to roofing materials of buildings; some window and door damage. No major damage to buildings. And/or. storm surge 6 to 8 feet above normal. Coastal roads and low-lying escape routes inland cut by rising water 2 to 4 hours before arrival of hurricane center. Considerable damage to piers. Marinas flooded. Small craft in unprotected anchorages torn from moorings. Evacuation of some shoreline residences and low-lying island areas required. CATAGORY3 OWinds of 111 to 130 miles per hour. Foliage torn from trees; large trees blown down. Practically all poorly constructed signs blown down. Some damage to roofing materials of buildings; some window and doordamage. Some structural damage to small buildings. Mobile homes destroyed. And/or storm surge 9 to 12 feet above normal. Serious flooding at coast and many smaller structures near coast destroyed; larger structures near coast damaged by battering waves and floating debris. Low-lying escape routes inland cut by rising water 3 to 5 hours before hurricane center arrives. Flat terrain 5 feet or less above sea level flooded inland 8 miles or more. Evacuation of low-lying residences within several blocks or shoreline possibly required. CATAGORY4 Winds of 131 to 155 miles per hour. Shrubs and trees blown down; all signs down. Extensive damage to roofing materials, windows and doors. Complete failure of roofs on many small residences. Complete destruction of mobile homes. And/or: storm surge 13 to 18 feet above normal. Flat terrain 10 feet or less above sea level flooded inland as faras 6 miles. Major damages to lower floors of structures near shore due to flooding and battering by waves and floating debris. Low-lying escape routes inland cut by rising water 3 to 5 hours before hurricane center arrives. Major erosion of beaches. Massive evacuation of all residences within 500 yards of shore possibly required, and of single -story residences on low ground within 2 miles of shore. CATAGORYS Winds greater than 155 miles per hour. Shrubs and trees blown down; considerable damage to roofs of buildings; all signs down. Very severe and extensive damage to windows and doors. Complete failure of roofs on many residences and industrial buildings. Extensive shattering of glass in windows and doors. Some complete building failures. Small Obuildings overturned or blown away. Complete destruction of mobile homes. And/or: stone surge greater than 18 feet above normal. Majordamage to lower floors of all structures less than 15 feetabove sea level within 500 yards of shore. Low-lying escape routes inland cut by rising water 3 to 5 hours before hurricane center arrives. Massive evacuation of residential areas on low ground within 5 to 10,miles of shore possibly required. Source: McElyea et al, 1982 4 C SEVERITY OF RISK IN HAZARD AREA - HAZARD AREA EXPOSURE TO DAMAGING FORCES Severity Erosion/ Wave Action/ Flooding High Rank Scour Battering Wind OCEAN ERODIBLE AEC 1 INLET HAZARD AEC 1 ESTAURINE SHORELINE AEC 1 :. V-ZONE 2 0 WETLAND AEC 2 0 A -ZONE 3 REST OF COMMUNITY 4 Exposure Level: High - 0 Moderate - 0 Low - 5 Source: McElyea et al, 1982 TO BISGAW TO CLINTON To WHITEVILLE 4 Approximate Scale 1" s 3 M leS CAROLINA BEACH KURE BEACH NEW INIIT NEW HANOVER COUNTY •\ TO JACMONVILLE X Y., LEGEND -;° Estuarine Shoreline AECs Ocean Erodible AECs • Inlet Hazard AECs Note: This map shows approximate areas of estuarine shoreline AECs, ocean erodible AECs, and Inlet Hazard AECs. This map should not be used for regulation purposes. These new forecasting tools are useful in predicting storm landfall tracts but are not related to storm intensity (Carter,1981). Hurricane intensity can be classified according to the Saffir/Simpson Scale based on wind speed, storm surge level and barometric atmospheric pressure. Based on these characteristics, a hurricane can be designated on a scale of 1 to 5 Table 1 located (Table 1). page 4. Hurricane intensity, as based on the Saffir/Simpson Scale, can create other storm elements that cause fatalities and property damage. These elements include wind and flood damage, wave action and erosion. New Hanover County is no exception to these forces. In fact, certain areas along the County's coast will be highly exposed to shoreline erosion and scouring, wave action/battering and flooding, in addition to wind damage. These areas, which have a severity rank of one, are Ocean Erodible Areas of Environmental Concern (AECs) , Inlet AECs and Estuarine Shoreline AECs. These areas are the most critical areas Table 2 located for hurricane protection planning with regard to exposure to hurricanes forces. Table 2 page S. displays these hazard areas and their severity of risk. Typically, Ocean Erodible AECs start at mean low water and go landward from the vegetation line a distance equal to 60 times the long term annual erosion rate plus the shoreline recession projected for a 100 year storm. This width generally varies from 200-400 feet. Inlet Hazard AECs are based on statistical analysis of inlet migration (using a 99.9 % confidence interval for a ten year period) and such factors as man-made alterations or unusual hydrologic features. The width of this area may vary from as little as 250 feet for stable inlets to 4,000 feet in more dynamic areas. This hazard area applies only to existing inlets , not to past or potential inlets (Owens,1981). The Estuarine Shoreline AEC's cover all land within 75 feet of the mean high water line. Estuarine lands may be subject to storm surge and general flooding. Federal Flood Insurance V Zones, which tend to overlap the above AECs, represent those areas likely to be flooded by the 100 year storm and exposed Figure 2 located to scouring/erosive wave action. (See Figure 2:) Detailed maps prepared by the U.S. Corps page 6. of Engineers and the N.C. Office of Coastal Management at a scale of 1 "= 400' are available for review at the County Planning Department. III. COASTAL STORM MITIGATION Reducing the risk of fatalities and property damage from hurricanes has always been the primary goal of local government planners and policymakers. Coastal storm mitigation falls under the local government's responsibility to protect the public health, safety, and general welfare (McElyea et al,1982). Because of this inherited responsibility, many local and state governments have reacted well to coastal stonn problems, especially flooding and high winds. Local government response has resulted in the delineation of storm prone areas as they relate to flooding. Additionally, land use controls, such as subdivision and zoning regulations, coupled with construction standards, greatly help mitigate storm hazards. The National Flood Insurance Program, created in 1968, was the first nationwide program to mitigate natural disasters by guiding the location and quality of development in flood prone areas. The program offers flood insurance to property owners in designated flood hazard areas. In return, local and state governments enact and enforce comprehensive floodplain management measures in order to protect lives and new construction from flooding (McElyea et al,1982). 7 Most of New Hanover County is vulnerable to hurricane -induced flooding. A major modeling effort of potential flooding levels within the County and the balance of eastern North Carolina by the N.C. Division of Emergency Management, the Federal Emergency Management Agency and the U.S. Army Corps of Engineers has produced "The Eastern North Carolina Evacuation Study". A primary product of this collaborative study is the Sea, Lake and Overland Surges from Hurricanes (SLOSH) model. Using this model, various storm surge scenarios are depicted based on the Saffir-Simpson Scale, storm movement/ direction, forward motion of the storm and the point of landfall. For any given storm category, based on the Saffrr-Simpson Scale, flooding would typically occur with more intensity from northwest bound hurricanes than from hurricanes with other directional headings. Using the model for New Hanover County, it is projected that the County would be subjected to a 13 foot storm surge based on a category 4 hurricane moving northwest with a forward motion of 12 miles per hour. A storm surge exceeding 17 feet could be expected with a category 5 storm moving northwest with the same forward speed of 12 miles per hour (Figures 3 and4). A full report describing these various hurricane scenarios is available for review at the County Department of Emergency Management. In New Hanover County, approximately 17,300 acres of land are located in the 100 year floodplain. This land includes swamps, but not marshlands or large waterbodies. Approximately 1,900 structures are located within the County's floodplain, based on an examination of aerial photos of the County (March 1990; scale I" = 400', F000dplain Management Plan,1990). Land use controls, such as subdivision regulations, can be utilized to reduce the risk of flood damages and erosion. In New Hanover County, subdivision regulations currently require several elements of hurricane hazard information for new developments. Site plans require that 100 year floodplains, topography, watercourses and other drainage features be displayed. Also, developers of projects located on barrier islands must submit an additional map displaying/describing the hurricane evacuation potential for the development. This description must include estimated road capacities, bridges and low elevation points of roads as well as estimates of mobilization, travel, and queuing delay times for safe evacuation. The Subdivision regulations are most effective at reducing flood damage when used in conjunc- tion with zoning and construction codes. Zoning is a very common device to manage land development. It is used to control the use of land and structures via setbacks, density and height limits, etc. Development in New Hanover County is restricted in hurricane hazard areas by the Zoning Ordinance. This Ordinance deals with several provisions that helps mitigate potential hazards associated with hurricanes. Key provisions include the Conservation Overlay District, non -conforming structures and performance and high density residential development controls. The Conservation Overlay District encompasses the entire unincorporated County with the exception of Pleasure Island. This district protects certain valuable natural resources. A number of these resources are hazard oriented areas such as swamp forest, natural ponds, marshes and maritime shrub thickets. The protection measures include varying setbacks, drainage restrictions with storm waterretention, and preservation of 50-100% of the resource in its natural state. For example, residential or commercial structures would be prohibited Figure 3 located page 9. Figure 4 located page 10. R 0 .0 STORM SURGE CONTOURS: CATEGORY 5 NW - CAT 5 - 12 MPH .... . ....... ........ — _4 elJ K f f� 5 r,L/ZZ,8 / 9 / 7 5 // 4 **� ' -S New Hanover County 7 6 5 4 3 -3 �2 78OW 770W 33*N 76*W 75OW 340N 74OW 35*N 360N 370N 74 Source: Eastern North Carolina Hurricane Evacuation Study, 1987 mo 0 O O O STORM SURGE CONTOURS: CATEGORY 4 Source: Eastern North Carolina Hurricane Evacuation Study, 1987 J U Figure 5 located page 13. L from being constructed along the shoreline due to strict setbacks imposed by the conservation overlay requirements. Setbacks range from 25 to 100 feet. Non -conforming uses/structures involve the use of a building or land which does not conform to the regulations of the zoning ordinance for the district in which it is located, either at the effective date of the ordinance or as a result ofsubsequent amendments. Generally, non- conforming structures may not be increased in area occupied and restrictions such as lot or yard requirements may not be reduced. If a non -conforming structure is totally or partially destroyed, it may be replaced provided notice of intent is provided within six months and a building permit is issued within twelve months. Reconstruction must meet current building codes and zoning requirements. Finally, if a non -conforming use is discontinued for more than 180 days, then the property must be used only for conforming purposes from that point on: Performance residential developments allow for flexible lot lines and setbacks, facilitating a site plan layout that avoids hazardous areas as opposed to the "cookie cutter" method of conventional subdivisions. Maximum density is based on a net tract acreage after subtracting all natural ponds, lakes, rivers, marshes and class IV soils from the gross acreage. Drainage regulations would also be required. High density residential developments like their cousin "Performance Developments" allow for flexible lot lines and setbacks, thereby creating a site plan layout around environmentally sensitive and hazard areas. Maximum density is based on site capacity standards, subtracting from the gross acreage such elements as water bodies(tidally or non -tidally influenced) and open space (flood boundaries, waterfront shorelines, conservation). Drainage regulations would be required also. Construction codes have also been widely utilized by local and state governments to reduce the hazard of flooding and intense winds by creating standards for flood -proofing, elevation and wind resistance. For example, Wrightsville Beach adopted a code in the mid 1950's requiring -all structures to be elevated on pilings eight feet above mean high water. Wind resistance standards appear in most state and local codes. The North Carolina State Building Code establishes "basic design wind velocities" of 110 to 120 miles per hour for its oceanfront counties (McElyea et al, 1982), (Figure 5). New Hanover County uses the State Building Code forall of theircommercial andresidential inspections fornew structures. The preservation of floodprone areas as open space in New Hanover County is the most effective means of mitigating storm damage. Preservation can be achieved through public acquisition, restrictive regulations and deed restrictions. Acquisition and relocation of existing structures by the County would be ideal but impractical due to the cost unless some Federal incentive is provided (Floodplain Management P1an,1990). The purchase of high risk areas for open space and recreation is one of the best mitigating measures a local government can use -The State has control over the Fort Fisher/ N.C. Aquarium beaches and it is purchasing Masonboro Island to become part of the Estuarine Research Reserve Program. 11 IV. EVACUATION Timely public evacuation for the beaches of New Hanover County (Wrightsville Beach, Carolina Beach and Figure Eight Island) is largely dependent upon the issuance of a hurricane waming by the National Weather Service and the efficient utilization of evacuation routes and shelters (Figure 6). Because the hurricane warning is usually given at least 24 hours in advance of the storm center's arrival, calculated evacuation times can be derived based on the following components. Evacuation time is composed of two separate components, clearance time and pre - landfall hazards time. Clearance time is defined as the time necessary for the relocation of all vulnerable evacuees to a safe area once the official evacuation order is issued. Clearance time can be broken down into three subcomponents: mobilization time, travel time and queing delay time. (a) Mobilization time is that period between the issuance of the evacuation order and the departure of the vehicles. It represents the time needed for evacuees to learn of the evacuation order, pack some belongings and leave. Three hours per household is a typical time period used in other studies and corresponds with preliminary survey results of residents and tourists during August and Septem- ber, 1983, on Wrightsville, Carolina and Kure Beaches. (b) Travel time is the period necessary for the vehicles to travel the length of the evacuation route at an anticipated speed, assuming no queing delays. (c) Queing delay time is the amount of time spent by vehicles in traffic jams when the capacity of the evacuation routes are exceeded by the number of vehicles entering those routes. A bottleneck would occur, forinstance, where fourlanes converge into a two lane bridge. The roadway capacity factors used to determine evacuation times for the area were obtained from a study in Currituck County (Collins,1983). Approximately 1575 vehicles per hour (vph) for two lane roads and 3222 vph for four lane roads will be used. Capacity levels would increase for roads with adequate shoulders, parking and turning lanes. The elements mentioned above take into account the following adjustments: common roadway capacity standards for engineers purposes, a 35% reduction in vehicular capacity due to adverse weather, a 15% reduction for stalled/wrecked cars and a 10% reduction for emergency vehicle use. In order for these capacity factors to have a large degree of validity, evacuation traffic must be strictly controlled using law enforcement personnel. Pre -landfall hazards time represents the period of time between when evacuation from the vulnerable area first becomes extremely difficult due to either gale force winds or stone surges that inundate evacuation routes and when the eye of the hurricane reaches the coast. A typical value for a severe hurricane registering a 'T' on the Saffir/Simpson scale would equate to four hours. This amount of time plus clearance time equals evacuation time. Figure 6 located page 14. R EO 12 K L91 North Carolina State Building Code's Basic Design Wind Velocities (in mph) 80 80 10o C 90 I I � 1 91 120 Source: North Carolina Building Code Council, 1981, Volume I - General Construction 13 Ee o C13 V) 0 CIS U :3 z u Q6 03 ts �t --Its -'TS it US fls CL O. 0 L EVACUATION TIMES An analysis of the components of evacuation time is shown below for Wrightsville Beach, the area south of Snow's Cut (Pleasure Island) and Figure Eight Island. Household and motel/condominium units are based on 1990 data derived from their respective communities and the Figure Eight Homeowners Association. While other areas of hazard exist in the County such as sounds, creeks and rivers (estuarine shoreline and 100 year floodplain), evacuation from these areas are considered to be adequate due to the short distance to the major evacuation mutes and low concentrations of populations served by these mutes. The analysis utilizes methods and assumptions drawn from work developed by the State Office of Coastal Management (McElyea. et al 1983), the Sea Grant Program atNCSU (Stone,1983) and an analysis prepared for Currituck County (Collins,1983). The analysis assumes the following "worst case" scenario: A catastrophic hurricane measuring 5 on the Saffir/Simpson Scale has dramatically shifted direction and is heading toward the southeast coastof North Carolina. The eye of the hurricane is expected to reach landfall within 24 hours. A Hurricane Warning has been issued by the National Weather Service and the County's local governments have issued evacuation orders through law enforcement and the media. Based on the 1990 population of the beaches within New Hanover County and the number of tourist on the coast, can the islands of Wrightsville Beach, Pleasure Island and Figure Eight Island (Carolina, Kure and Fort Fisher) be evacuated in a safe and timely manner? The analysis displayed below is considered conservative due to certain assumptions concerning traffic flow. Due to the severity of the storm, up to 30% of the short-term renters and residents would most likely leave before the evacuation orderis given (Stone, 1983).This 30% deduction is incorporated in the calculations below. Wrightsville Beach Total Evacuation Time = Total Clearance Time + Pre -Landfall Hazard Time = 6.53 hours + 4 hours =10.53 hours The total evacuation time of 11 hours (rounded) indicates that Wrightsville Beach could be safely evacuated if the evacuation order is concurrent with a Hurricane Warning. This conservative estimate also includes the following variables: Total Clearance Time = Mobilization Time + Travel Time + Queuing Delay Time = 3 hours + .25 hrs1I + 3.28 hrsl2 15 1. Travel Time: Under free flow conditions, a car should be able to travel from any point on Wrightsville Beach to the mainland in a maximum of 15 minutes. 2. Queuing Delay, Time: Queuing delays will result from vehicles coming from residential streets onto Highways 74 and 76 (Waynick Blvd., Lumina Ave., and Causeway Dr.). It is assumed that the traffic coming off the drawbridge onto the mainland will be controlled to prevent back-up. Calculations are as follows: • Assume that a total of 3273 households and motel/condominiums require evacuation. Each has an average of 1.6 vehicles per household for a total of 5,237 vehicles. • Assume also that one half (2619) of the vehicles will evacuate from the southern end of the beach and one half (2618) from the northern beach evacuate at the same time along a two lane road. Since evacuation will take place on two separate, two lane stretches of road at the same time, maximum queuing delay time would be calculated using the larger of the two vehicle figures determined above. Queuing Delay Time = 2619 vehicles 1575 vph capacity Queuing Delay Time = 1.66 hours • Assume that all vehicles (5237) must travel on a four lane road to the mainland. The maximun queuing delay time would be: Queuing Delay Time = 5237 vehicles 3232 vph capacity Queuing Delay Time =1.62 hours • The Wrightsville Beach drawbridge, according to the Department of Transportation, will not be opened during high winds and therefore, would not be a significant delay in traffic. Total maximum queuing delay time = 1.66 hrs. + 1.62 = 3.28 hours Pleasure Island (Carolina Beach,Kure Beach, Fort Fisher) Total Evacuation Time = Total Clearance Time + Pre -Landfall Hazards Time 6.65 !tours + 4 hours = 10.65 hours The total evacuation time of 10.65 hours indicates that this area of the County could be safely evacuated if evacuation is ordered concurrent with a Hurricane Warning. L 16 Total Clearance Time = Mobilization Time + Travel Time+ Queuing Delay Time 3 hours + .5 hrsll + 3.15 hrs12 = 6.65 hours 1. Travel Time: Under free flow traffic conditions, a vehicle should be able to travel from any point in the County south of Pleasure Island to north of Snow's Cut within 30 minutes. 2. Queuing Delay Time: Queuing delays will result from vehicles coming from residential streets onto Carolina Beach Road (highway421 south). Computations are addressed below: • Assume that a total of 4195 households and motel/condominium groups will require evacuation. Each has an average of 1.6 vehicles per household, for a total of 6712 vehicles. • Assume that one quarter 1678 of the vehicles will evacuate from the area south of Carolina Beach north to Carolina Beach, using the two lane section of US Highway 421. Queuing Delay Time = 1678 vehicles 1575 vph capacity Queuing Delay Time = 1.07 hours • Assume that all vehicles 6712 will evacuate north from Carolina Beach to north of Snow's Cut, using the four lane section of US Highway 421. Queuing Delay Time = 6712 vehicles 3232 vph capacity Queuing Delay Tme = 2.08 hours Total maximum queuing delay time =1.07 + 2.08 hours = 3.15 hours Figure Eight Island Total Evacuation Time = Total Clearance Time + Pre -Landfall Hazard Time = 3.65 hours + 4 hours = 7.65 hours 17 The total evacuation time of 7.65 hours indicates that Figure Eight Island would be safely evacuated if evacuation is ordered concurrent with a 12 hour Hurricane Warning. Total Clearance Time = Mobilization Time + Travel Time 11 + Queuing Delay Time 12 3.65 hours = 3 hours + .25 hours .40 hours 1. Travel Time: Under free flow traffic conditions , a car should be able to travel from either end of Figure Eight Island to the mainland in 15 minutes. 2. Queuing Delay Time: Queuing delays will result from vehicles coming from residences onto Beach Road and then onto Bridge Road. Calculations are given below: • Assume that a total of 212 households require evacuation. Each has an average of 2 vehicles per household for a total of 424 vehicles. • Assume that one half of the vehicles (212) will evacuate simultaneously from the northern end. For these two-lane stretches of road, maximum queuing delay time would be: Queuing Delay Time = 212 vehicles 1575 vph capacity Queuing Delay Time = .13 hours • Assume that all vehicles must travel on the two-lane Bridge Road to the mainland. This maximum queuing delay time would be: Queuing Delay Time = 424 vehicles 1575 vph capacity Queuing Delay Time - _ .27 hours Total Maximum Queuing = .13 hours + .27 hours Delay Time = .40 hours V. POST DISASTER RECONSTRUCTION PLAN The following information presents proposed policies and procedures that may be implemented in New Hanover County after a massive and damaging hurricane strike (a category4 storm on the Safr-Simpson scale). If adopted, these policies would compliment the adopted Hurricane Evacuation Plan supplied by the Department of Emergency K i K n Management and would be considered for incorporation into the Wilmington -New Hanover County Land -Use Plan Update. The primary thrust of these proposed policies is to permit the County to rebuild at a smooth and controlled pace ensuring public safety and protecting lives and property. VI. INITIAL POST DISASTER RESPONSE Initially, it should be mentioned that immediate cleanup and removal of debris from public roads is the responsibility of the North Carolina Department of Transportation. In other situations, the Assistant County Manager is responsible for the overall supervision of cleanup and disposal of County debris resulting from a stone. The responsibility for directing reconstruction within New Hanover County after a damaging storm should rest with a "Recovery Task Force". This committee should reflect a broad representation of community interests. At a minimum, this committee should be composed of the following individuals: 1. Two elected officials (County Commissioners and/or City Council) 2. County Manager or his designee 3. Emergency Management Director 4. County Engineer 5. County Health Director 6. Planning Director 7. Zoning Administrator 8. Chief building inspector 9. Property Management Director 10. County Sheriff 11. County Fire Marshal 12. One representative from either the realty or construction community (preferably the construction f eld) 13. Representative from Southern Bell 14. Representative from C.P.& L. 15. Representative from the City of Wilmington Members of this task force shall be appointed annually by the Board of County Commissioners. 19 VII. TASK FORCE RESPONSIBILITIES The task force shall be responsible for advising the Board of Commissioners on a diverse range of post -storm reconstruction issues. A principle function of the task force is to receive and assess damage reports from the "local damage assessment team" or "control group" as defined in the Hurricane Evacuation Plan (Rev.1990) prepared by the Department of Emergency Management. Other responsibilities of the recovery task force would include: 1. Reviewing the nature of the damages, identifying and evaluating alternative program approaches for repairs and reconstruction and formulating recommenda- tions for handling County recovery. 2. Recommending possible rezoning changes in areas of severe damage to accommo- date rebuilding 3. Setting a definitive, yet flexible calendar of reconstruction goals in conjunction with other local officials. 4. Initiating requests for repairs and upgrading critical utilities. 5. Recommending the expiration or extension of the moratorium on structural repairs. 6. Recommending the lifting or extension of the moratorium on new development. 7. Initiating negotiations for relocations and acquisitions of property. 8. Participating in federal hazard mitigation planning. The task force could also recommend changes in zoning, subdivision and mobile home park/travel trailer regulations, building codes or any other regulations which it deems necessary or advisable to prevent a recurrence of coastal storm damage. As mentioned, the local damage assessment team is responsible for locating and identifying structures that have been damaged by a hurricane. Based on their assessment, this team can advise and identify for the Inspections Director those structures which have been destroyed, received major damage (foundation, roof, other structural elements) or minor damage (minimal repairs to windows, doors, floors or other minorstructural elements). The Department of Inspections can then verify what has been done by the assessment team and classify each structure accordingly. Additional out of town building inspectors may be required depending on storm severity. A building moratorium shall be declared in effect upon the occurrence of one or more of the following elements: M X 20 U K * Duration of Moratorium. May be cancelled or extended by the Reconstruction Task Force or by resolution by Board of Commisioners. OEmergency repairs can be done anytime - examples: minor interior repairs and repairs necessary to prevent injury, loss of life or imminent collapse. Source: Nag's Head Planning Department, 1988 21 Figure 7 located page 21. EO U 1. The County is directly hit by a category 4 storm or greater based on the Saffir- Simpson scale as determined by the National Weather Service. 2. The County is declared a disaster area by either the Governor of North Carolina or the President of the United States. 3. Several hundred or more structures have received major damage or been destroyed as determined by the Inspections Department. 4. Upon determination by the local damage assessment team chairman in accordance with N.C.G.S.14-288 as amended, an initial building moratorium may be declared for the protection of lives, safety and property or due to the inability of the county to maintain acceptable levels of public order and services. - Once a building moratorium has been declared, the recovery task force will be activated. The initial building moratorium shall be in effect for at least two days (See Figure 7). Building permits will not be issued during this time. Building permits will not be issued within thirty working days following the termina- tion of the initial moratorium for the replacement of any structure which has been destroyed. The replacement of any structure shall be subject to meeting all the requirements of the County's zoning regulations and, of course, all applicable building codes. For structures that have received major structural damage from a stone event, a seven working day waiting period will be required following the expiration of the initial moratorium. All necessary repairs shall meet applicable zoning and building code require- ments prior to the issuance of a building permit. Permits forthe repairof structures thathave received only minordamage may be issued following the expiration of the initial moratorium. All minor repairs will be in accordance with applicable zoning and building code regulations. Building permits issued prior to a massive stone event shall be void and not reissued for at least thirty (30) working days following the expiration of the initial moratorium. This period of time may be reduced on a case -by -case basis if in the opinion of the Director of Inspections, sufficient staff is available to provide inspections of the structures once construction resumes. Revoked building permit applications shall be reissued at no charge. Preliminary site plans submitted to the County Planning Department prior to the storm event which have not received approval by the Planning Board shall not be reviewed for a period of thirty (30) days following the expiration of the initial moratorium. Scheduled review periods shall be established after the moratorium is lifted. This thirty (30) day moratorium shall also apply to any submittal of final plats, minor subdivisions, mobile home park/travel trailer plans, rezonings, special use permits, and conditional use applications. Submittal dates shall be adjusted accordingly to reflect the moratorium termination. 22 All moratoriums may be cancelled -or extended by the Recovery Task Force or resolution by the Board of County Commissioners. Emergency repairs may be permissible to prevent injury, loss of life or imminent structural collapse. Minor interior repairs may also take place to prevent additional damage from wind and water. VIII. CONCLUSION AND POLICY RECOMMENDATIONS Based on Hurricane Hugo in 1989 and other documented literature, it has been realized that any intense hurricane event of 4 or 5 on the Saffir/Simpson Scale would create a significant amount of property damage in New Hanover County resulting in recovery operations that could take years. Due to the potential for such naturally occurring events, the following policies are suggested for inclusion in the Wilmington -New Hanover County Land -Use -Plan Update to help insure the orderly reconstruction of public property POLICY: Immediate clean-up and removal of debris from public roads is the responsibility of the North Carolina Department of Transportation. Public expenditure of funds for the repair or reconstruction of any private road or vehicular easement which is damaged or destroyed as a result of an intense stone event shall not occur, except in conjunction with the repair of the County's sewer. All other private roads will be the responsibility of the individual landowners. POLICY: The Assistant County Manager shall be responsible for the overall supervision of clean-up and disposal of County debris resulting from an intense storm event. POLICY: The responsibility for directing reconstruction within New Hanover County after a damaging stone shall be the Recovery Task Force. This task force shall be responsible for advising the Board of County Commissioners on a diverse range of post - storm issues. POLICY: A building moratorium of no less than thirty (30) working days following the initial two (2) day moratorium shall not occur unless authorized or extended by the Recovery Task Force or resolution by the Board of County Commissioners. X C 23 POLICY: Following a storm event, the County will take advantage of opportunities �J to acquire or purchase land located in storm hazard areas which are rendered unbuildable. The property should satisfy objectives including, but not limited to the conservation of open space, scenic areas and provision of public water access. After a major storm event, there are numerous federal and state programs that are available to the County to aid in disaster relief, recovery and reconstruction. These programs canprovide assistance or funds through local government to individuals, businesses, families and non-profit associations. Some of these programs can only be implemented upon declaration of a major disaster by the President of the United States. Other programs can be made available independently of a Presidential Declaration of a major disaster emergency. POLICY:. It shall be a policy of the County to retain on a seasonal basis an Assistance Facilitator/Consultant who, as directed by the County Manager, will be responsible for: 1. Determining the types of assistance available to the county and the type of assistance most needed, 2. Assisting in the coordination of federal disaster recovery effort, O3. Coordinating federal and state programs of assistance, 4. Informing the County citizenry of types of assistance programs available, 5. Recommending to the Recovery Task Force and Board of Commissioners programs which are available and then acting as facilitator in securing those programs. O 24 REFERENCES 1. Carter, T.M. 1981, "Probability of HurricanelTropical Storm Conditions: A Users Guide For Local Decision Makers". USDOC/NCA-NWS. 2 McElyea, W.D., D.J. Bfrowers, and D.R. Godschalk, 1982, "Before The Storm: Managing Development to Reduce Hurricane Damages," Center for Urban and Regional Studies, UNC-Chapel Hill. 3. Stone, J.R., 1983, "Hurricane Emergency Planning: Estimating Evacuation Times for Non -Metropolitan Communities," Working Paper 83-2, Sea Grant Program, NCSU. 4. Collins, W.E.,1983, "Carrying Capacity Methodolgy," Nags Head, NC. 5. Nags Head Planning Department, 1988, " Hurricane & Storm Mitigation and Reconstruction Plan," Town of Nags Head, Nags Head, N.C. 6. New Hanover County Planning Department, 1990, "Floodplain Management OPlan," New Hanover County, Wilmington, N.C. 7. New Hanover County Department of Emergency Management, 1990, "New Hanover County Evacuation Plan," New Hanover County, Wilmington, N.C. 8. U.S. Army Corps of Engineers, Federal Emergency Management Agency, N.C.-Division Emergency, 1987, "Eastern N.C. Hurricane Evacuation Study," US COE, Wilmington District. 9. Carter, T.M., 1981, "Probability of HurricanelTropical Storm Conditions: A Users Guide for Local Decision Makers," USDOC/NCA-NWS. 10. Owens, D.. 1981, "The Management of Oceanfront Development in North Carolina," paper presented at the 7th annual Conference of The Coastal Society, October 11-14, 1981, Galveston, Texas. O 25