Hazard zone II 



WIND 

 140 MPH 



Hazard zone III 



If the surge 

 doesn't get you, 

 the winds will 



Builders could make more informed decisions 

 about construction standards if they knew what 

 forces they were up against in a given area, says Dr. 

 Jerry L. Machemehl of North Carolina State Univer- 

 sity. 



With Sea Grant funding, Machemehl is mapping 

 coastal hazard zones for five different classes of 

 storms. When completed, the maps will show the geo- 

 graphical potential for flooding, beach erosion, 

 winds, storm surge, rainfall, inlet migration and 

 overwash. The storm classifications range from 

 Northeasters (winds less than 74 miles per hour) to 

 catastrophic hurricanes (winds over 150 miles per 

 hour). 



The maps will delineate four hazard zones in 

 coastal North Carolina. 



Hazard Zone I— which is the most seaward, in- 

 cluding beach, berm and the first line of cottages- 

 will be subject to the full impact of hurricane force 

 winds, waves and flooding from storm surge. 

 Buildings in this zone will be susceptible to battering 

 by debris and may be floated off their foundations by 

 storm surge. In addition, they may be undermined by 

 severe beach erosion. 



Hazard Zone II also will be subject to a hurricane's 

 full impact; however, buildings will not be affected 

 by beach erosion. 



Hazard Zone III will be subject to hurricane force 

 winds and flooding from rainfall, while structures in 

 Hazard Zone IV will be subject to hurricane force 

 winds only. 



Machemehl's preliminary findings indicate that in 

 North Carolina erosion of up to 30 feet, rainfall up to 

 20 inches or more, and winds of 130 to 140 miles per 

 hour are not uncommon for a 100 year storm. 



When his maps are completed, Machemehl hopes 

 prospective builders will use them when deciding 

 what storm forces to build for. Special precautions in 

 coastal construction make building costs about 5 per- 

 cent higher than in inland areas, Machemehl 

 estimates. 



The yatch club, Wrightsville Beach, after Hurricane Hazel 



©©foGSfMi}© ®ff 6 mM b®mh hmm wiry 



Shortly after Hurricane Hazel "tore up jack on the 

 coast" in 1954, Kern Church sat down and wrote Ap- 

 pendix D of the North Carolina Residential Building 

 Code. "We had to do something," says Church who is 

 Deputy Commissioner of Insurance, Engineering and 

 Building Codes Division for the state. 



The building code and its appendix are one of three 

 major controls on the quality and location of con- 

 struction in North Carolina beach communities. The 

 other two programs are the Coastal Area Manage- 

 ment Act and federal flood insurance. 



Appendix D deals specifically with coastal con- 

 struction and is primarily concerned with wind storm 

 resistance. Houses within 150 feet of the mean high 

 water line are required to have pilings sunk eight feet 

 below the natural grade of the lot (a figure Church 

 says "I took off the top of my head"). Tiedowns must 

 be used to secure roofs, walls and foundations. 

 Though the Residential Building Code is used state- 

 wide, Appendix D must be adopted locally. And local 

 building inspectors enforce the regulations. 



The Coastal Area Management Act (CAMA) 

 delineates ocean hazard areas including beaches, 

 frontal dunes, excessive erosion areas and inlet lands. 

 Development is kept behind the frontal dune. Set- 

 back guidelines, based on a 25-year storm surge, 

 prohibit permanent structures in areas ranging from 

 61 to 156 feet landward from the toe of the frontal 

 dune. Similarly, development within 75 feet of the 

 mean high water line on the sound side requires a 

 permit. In effect, CAMA first influences the location 

 of construction, protecting natural features. Second- 

 ly, it calls for enforcement of state building codes, in- 



cluding Appendix D, in the areas of environmental 

 concern. Local building inspectors are responsible for 

 permit letting for sites smaller than 20 acres or 

 60,000 square feet. 



Federal flood insurance is intended to provide a 

 tool for regulation of development in flood prone 

 areas and low cost flood insurance protection to in- 

 dividuals living in these areas. The coverage is writ- 

 ten by private insurers and is federally backed 

 through the Federal Insurance Administration (FIA). 



Communities are required to assess flood poten- 

 tials and adopt necessary guidelines to protect struc- 

 tures from 100-year flood levels. Elevations required 

 in coastal North Carolina range up to 14 feet above 

 mean sea level. 



Individually or taken together, the three programs 

 are not without problems. Administrators of the pro- 

 grams acknowledge that they do not mesh, and that 

 they allow some construction to "fall through the 

 cracks" with little control. Some programs are 

 criticized for not being stringent enough. Each of the 

 programs is administered in a given geographic area. 

 "None of these areas really correspond. You may 

 have one, two or three permits in a given area," says 

 Mike Black, Chief of Technical Services for the Office 

 of Coastal Management. 



Rob Moul, coastal management consultant for the 

 CAMA staff, cites another— and often raised- 

 concern. On occasion, he says, it seems federal flood 

 insurance actually encourages hazardous develop- 

 ment. 



(See "Rethinking, " page five) 



