d. Alignments, lengths, and locations of the various reflecting surfaces in 

 the area. 



e. Refraction of waves caused by differentials in depth in the area seaward 

 of the site, which may create either a concentration or a diffusion of 

 wave energy. 



Storms and wave data 



Two distinct types of storms influence coastal processes in New England. 

 These are extratropical and tropical cyclones, distinguished primarily by their 

 place of origin. Extratropical cyclones are the most frequent variety occurring 

 in New England. Tiiese stonns derive their energy from temperature contrast 

 between cold and warm air masses. Low pressure centers frequently fonn or 

 intensify along the boundary between cold dry continental air masses and 

 warm marine air masses off the coasts of Georgia and the Carolinas and move 

 northeasteriy more or less parallel to the coast. Depending on the track of the 

 stonn, high onshore winds may be generated from northeast clockwise through 

 southeast resulting in large waves and extreme stomi surge. Tropical cyclones 

 form in warni moist masses over the Caribbean and the waters adjacent to the 

 west coast of Africa. Energy for these storms is provided by the latent heat of 

 condensation. When the maximum wind speed in a tropical cyclone exceeds 

 121 kni/hr (75 mph), it is classified as a hurricane. Tropical cyclones and hur- 

 ricanes affecting the New England coast generally approach from the south and 

 the east, and may result in great wave and surge action. The hurricane and 

 tropical storm season in New England generally extends from August through 

 October. 



Measured prototype wave data covering a sufficiently long duration from 

 which to base a comprehensive statistical analysis of deepwater wave condi- 

 tions for the Camp Ellis Beach area were not available. However, statistical 

 wave hindcast estimates representative of lliis area were obtained from the 

 WES Wave Infonnation Studies (WIS), which includes a 20-yr hindcast period 

 (1956-1975). The hindcast (Hubertz et al. 1993) was obtained at WIS sta- 

 fion 99 (43.50N, 70.25W) in the North Aflantic Sea. Data obtained at the 

 deepwater station are presented in Table 1 . These data indicate that the major- 

 ity of waves approach Camp Ellis Beach from the 103-deg (approximately 

 east-southeast) direction. Hindcast simulations were perfonned to detennine 

 wave characteristics at the station resulting from severe stonns (i.e., the Bliz- 

 zard of 1978 and the Halloween Stonn of 1991). Maximum deepwater waves 

 at the hindcast station during the stonns (Hubertz and Curtis 1993) were: 

 13-sec, 7.9-m (26-ft) waves from 78 deg for the 1978 storm and 15-sec, 6.1-m 

 (20- ft) waves from 80 deg for the 1991 stomi. 



16 



Chapter 3 Test Conditions and Procedures 



