seaboard since March 1962. According to the New England Division, this 

 storm has a recurrence interval of 75 years. Storm surge was recorded at 

 Provincetown, Massachusetts, at 1.1 meters above a spring high tide of about 

 3.4 meters (G. Geise, Provincetown Center for Coastal Studies, personal com- 

 munication, 1978). Breaking waves of 2.7 meters were observed on the U.S. 

 Coast Guard Beach, 3 kilometers north of the test area. 



(2) Impact . A field inspection in February 1978 revealed massive 

 erosion on the seaward face of the experimental dunes. Of particular impor- 

 tance, however, is the fact that the plots were overwashed at only one loca- 

 tion, the center of plot 3. Plot 3 was bisected by two foot and vehicular 

 thoroughfares that had persisted since 1973. Figure B-2 is a ground photo of 

 plot 3, showing the traffic area, taken in 1977, 4 months before the storm. 



Figure B-2. Plot 3 (American beachgrass on 60-centimeter 



spacing), October 1977. Note foot and vehicular 

 pathway through plot. 



2. Long-Term Erosion and Accretion . 



a. Shore Migration Adjacent to Test Plots . Figure B-3 compares the initial 

 (April 1970) and final (November 1977) elevational profiles along the 762-meter 

 test section at the south spit of Nauset Harbor. During the 91 months of moni- 

 toring, the landward shoreline in plots 1, 2, and 3 remained stable. The 

 landward shoreline of plots 4 and 5 retreated about 15 to 18 meters, an annual 

 erosion rate of about 2 meters per year. Erosion on the seaward shore followed 

 the same general pattern. Annual erosion was less than 1 meter per year in 

 plot 1 and more than 3 meters per year in plot 5. In general, the spit was 

 relatively stable near its southern apex, while erosion was greater on both the 

 seaward and landward shores of its more northern extremities. 



40 



