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2.3 PHYSICAL OCEANOGRAPHY AMD DISPERSION 



Since the 50-Mile Site is located midway between the mouth of New York 

 Harbor and the edge of the continental shelf, oceanographic conditions 

 at the site are representative of typical shelf waters with reasonably 

 well-defined seasonal temperature, salinity and density cycles. The 

 site is not significantly affected by freshwater discharges of the Hudson 

 River plume or incursions of oceanic slope waters. Circulation patterns 

 at the Site are complex and variable being driven by quasi -random phe- 

 nomena such as wind shear, tides, and storms. A net southwesterly flow 

 along bathymetric contours has been reported to be normal, although 

 northeasterly reversals for periods exceeding two months have been 

 observed (Chapter 3). 



Oceanic diffusion studies indicate that four hours after its discharge 

 (the initial mixing period), sewage sludge is expected to be diluted one 

 part sludge to about 30,000 parts of seawater (Section 13.2). This dilu- 

 tion is a result of a two phase process: a very rapid Initial wake dis- 

 persion, followed by slower oceanic dispersion processes (Section 13.2). 

 Oceanic dispersion processes are expected to be at least as effective 

 in dispersing and diluting sewage sludge at the 60-Mile Site as at the 

 12-Mile Site. 



2.4 OTHER USES OF THE SITE 



Few activities occur in or near the 50-Mile Site: vessel traffic is 

 light, fisheries resources are not large, and commercial fishing in the 

 area Is limited (Chapter 4). Further, the 50-Mile Site is not identified 

 as an area with significant potential for minerals or other forms of 

 development (Section 4.5). 



2.5 TYPES AND QUANTITIES OF WASTES 



Transfer of all sewage sludge disposal operations from the 12-Mile Site 

 to the 60-Mile Site would result in the discharge of approximately 6.7 

 million wet tons (1981 value) of 3-5 percent solids sewage sludge to an 

 area of the continental shelf not previously affected by waste discharges 

 (Chapter 5). 



2.5 EFFECTS OF SEWAGE SLUDGE DUMPING 



The possibility of environmental and human health effects of sewage 

 sludge dumping at the 60-Mile Site must be assessed in order to redesig- 

 nate the site. In addition, the economic effects are an unavoidable 

 reality and should be examined. One of the major adverse effects of 

 moving sewage sludge dumping to the 60-M1le Site would be an increased 

 financial burden upon all municipalities and regulatory agencies Involved 

 In the dumping process. 



Water Quality Effects 



Waters of the outer continental shelf, which includes the 60-M11e Site, 

 have water quality characteristics Intermediate between those of the open 

 ocean and those of the New York Bight apex. In comparison to the apex, 



B-3 



28-914 O— S 



