V 



breaches had developed with a narrow band of salt marsh along the bay shore- 

 line. Bay shoreline erosion reduced the barrier width to 107 meters by 1941 

 (Table 54). In 1952 a massive overwash placed sediment in a large fan shape, 

 extending as far as 405 meters beyond the bay shoreline, but 91 meters of the 

 bayward perimeter of the washover was removed by tidal currents between 1952 

 and 1978. 



The U.S. Army Corps of Engineers constructed sand dunes during 1965 and 

 1967 across the massive washover breach at belt G (U.S. Army Engineer Divi- 

 sion, New England, 1979). By 1978 these dunes were 5 meters high, 100 meters 

 wide, and continuous except for two breach vashovers north and south of the 

 belt (Fig. 125) . Back-barrier dunes developed poorly since the artificial, 

 seaward dunes reduced overwash and aeolian sand supply for dune building. A 

 series of small, low dune ridges, which were remnants of drift-line dunes that 

 failed to fuse into the dune line, were interspersed throughout the salt 

 marsh. Since these low ridges acted as barriers to frequent tidal flooding 

 from the bay side, much of the young salt marsh at belt G had a very low 

 biomass. 



480W 400 



'iliqulnto 



Unvegetated 

 Ammophilo 

 Lothyrus jo ponlcus 

 Artemiaia stelleriono 

 Solidogo sempervircns 

 Myrico pensylvonica 

 Aqropyron punqens 

 Sporting patens 

 Sporting alternif loro 

 Other 



100 pet cover 

 50 



Figure 125. Vegetative-physiographic transect of belt G. 



Belt K is less than 40 years old since New North Beach had not extended 

 as far south as belt K. in 1938 (Figs. 90 and 124). This belt was very broad 

 in 1952, and was characterized by three spit recurves. Two of these recurves 

 had fused by 1970, and a salt marsh developed in the protected center of the 

 barrier. Sheet overwash buried sections of the seaward recurve in 1978. 



The seaward spit recur"e had been severely eroded by ocean waves and cur- 

 rents. Dense, healthy Ammophila breviligxilata grew on both the ocean- and 

 bay-facing dunes (Fig. 126). Toward the center of the western spit recurve, 

 depauperate Ammophila bveviligulata grew with extensive stands of Artemisia 

 caudata and Chvusopsis falcata. Although the belt is only 26 years old, 

 Ammophila bveviligulata has already begun to decline in vigor in the interior 

 of the dune field in the absence of accreting sand due to r.he development of 

 high foredunes. 



204 



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