Table 53. Ratio of width to length of 

 New North Beach. 



Year 



Avg. wl 



idth 



Length 



Wid 



th/length 





(m) 





(m) 





(m) 



1851 



505 





8500 





0.06 



1886 



153 





6700 





0.02 



1938 



626 





4100 





0.15 



1952 



445 





5200 





0.09 



19 78 



279 





6700 





0.04 



of the barrier to overwash breaching and inlet formation. In 1851, just after 

 the 1846 inlet had created the island at the southern end of the spit system, 

 the New North Beach section had a width-to-length ratio of 0.06; this ratio 

 decreased to only 0.02 in 1886 as the spit remnants migrated landward. During 

 early development of New North Beach, the ratio was quite high (0.15) because 

 the spit recurves, prominent at the southern end, were very broad. Since 1938 

 this ratio has decreased. By 1978 the ratio (0.04) was less Chan it had been 

 after the last inlet formed. The decrease in width-to-length ratio suggests 

 that although few North Beach in 1978 was not as long as it had been in 1851, 

 it was more vulnerable to inlet breaching. 



Overwash lias been locally important in increasing barrier width and shift- 

 ing landward the position of dunes and salt marshes. Unlike Old North Beach, 

 New North Beach has not, however, migrated westward by means of overfish. The 

 distance between the Chatham mainland and the back barrier has remained fairly 

 consistent In the last 40 years. New North Beach is very narrow and salt 

 marshes have not developed substantial peat deposits. If an inlet were to 

 form through New North Beach, the barrier would very quickly erode landward. 



5 . Vegetative-Physiographic Transects. 



a. Introduction . Field research was conducted on North Beach and Nauset 

 Spit-Orleans during 1978 to d»t«rnine the successive sequence of plant corcaun- 

 ities that develop on washovers and to characterise physiographic features 

 resulting froa washover stabilisation, inlet dynamics, and plant coaminity 

 development. Fifteen areas were chosen for study: eight were located on 

 Old North Beach, five oa New North Beach, and two on Nausefc Spit-Or leans 

 (Fig. 90). These areas were selected on the basis of overwash history, 

 vegetative characteristics, and present physiographic features. An etteispt 

 was made to include all the various plant cosssunitieo and physiographic 

 features present on Nauset Spit. 



b. tfethodology . At each site, an elevation transect was established per- 

 pendicular to the beach (Fig. 108). Stakes were used to mark these transects 

 for tut ire use. Elevation readings were taken using a surveyor's level at 

 10-meter intervals and at points of significant topographic change. 



A vegetation sampling program was conducted during late July and August 

 1978. Belt transects 30 meters wide were established, centered along each 

 of the 15 elevation transects in order to sample large, representative areas 

 (Fig. 108). At a 10-meter interval, 30-meter-long transects were constructed 



185 



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