correlation of the cores with stratification indicated by the seismic profiles. Based on this 

 evidence, minimum sand thicknesses were calculated for each area. Each of the borrow areas 

 was then planimetered to calculate the area in square yards and this figure was multiplied by 

 the blanket thickness in yards. This product represents a total minimum sand volume for 

 each borrow area. 



Area A (south of Rockaway Beach) is the largest of the potential borrow areas. The shelf 

 surface is characterized by a gentle seaward dip and exhibits few irregularities. Fourteen 

 cores in this area contain sand with sedimentary properties closely matching native beach 

 material on Rockaway Beach and Coney Island. Based on the cores and geophysical record 

 interpretation a minimum 3-yard thickness of suitable material covers the entire area. From 

 this figure the calculated total volume of sand for Area A is 1.03 X 10 9 cubic yards. Six of 

 the cores conclusively support this minimum thickness (Fig. 22); the remaining eight cores 

 were limited to less than 9 feet in recovered length but contained good sand through their 

 entirety. Geophysical records near the eight cores show no changes in sediment type at 

 depth which would preclude using the minimum 9-foot-sand thickness. Reasons for the 

 limited penetration of these cores are not evident; small quantities of coarse sand in the 

 bottoms of some cores suggests that localized pockets of coarser material may be present 

 and may have limited core barrel penetration. Quantities of coarse (> 2 millimeters in 

 diameter) sediment are limited. 



Geophysical records indicate that the borrow material is stratified, having a gentle 

 seaward dip. Buried stream channels projecting south from the eastern section of Rockaway 

 Beach are found in several of the geophysical records and possibly are filled with sediment 

 having variable sedimentary properties. Most channels are buried below usual dredging 

 depths, and are not a factor in extraction of beach fill but should be considered a factor 

 when planning for foundation design of any offshore engineering structures. 



An elongate borrow area extending parallel to shore from the Shrewsbury River north 

 around Sandy Hook to Lower New York Bay is designated Area B. It completely encloses 

 Area C which will be considered separately because of the presence of highly unusual 

 crossbed structures. Area B contains nine cores which reveal that fine to medium sand 

 suitable for placement on adjacent beaches exists for a minimum thickness of 2 yards. Two 

 cores provide some exception to this apparent thickness: cores 5 and 7 (immediately south 

 of Area C) exhibit fine silty sand and coarse sand with pebbles. Because of the proximity of 

 both cores to the Highland Channel these underlying sediment types are probably of fluvial 

 origin. (See Figure 4.) The geophysical records and Coast Guard cores B-9 and B-17 

 (Table 6) indicate that clean sand is significantly thicker north of Atlantic Highlands than 

 the 2-yard minimum. Using the 2-yard thickness over Area B as a minimum yields a sand 

 volume of over 314 X 10 6 cubic yards. The northwestern boundary in Lower Bay defines 

 the limits based on data of this report and does not necessarily reflect limits of borrow 

 material in that direction. 



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