extend from Watch Hill Point in Rhode Island to Orient Point on Long Island 

 while the western boundary extends from Throgs Neck to Willets Point. Using 

 a slightly different eastern boundary (extending from Orient Point, Long 

 Island through Plum Island, to Race Point on Fishers Island and thence to 

 Groton Long Point) the National Ocean Survey computed the volume of water in 

 the Sound to be approximately 16, 800 billion gallons or 15.^ cubic miles. 



The average annual fresh water inflow as previously stated is 

 approximately 6,200 billion gallons, equal to 37 percent of the total volume. 

 Most of the fresh water inflow (80 percent or more) is into the eastern end 

 of the Sound from the Connecticut and Thames Rivers. Assuming that the aver- 

 age annual precipitation is 36 inches, an additional 800 billion gallons a 

 year of fresh water falls directly on the Sound. 



Riley (29) , Swanson {33) f LeLacheur and Sammons (50) and others 

 have described the general pattern of circulation. The dominant horizontal 

 motions are the semidiurnal tidal currents; reversing currents occur along 

 the coast while in central Long Island Sound the currents are elliptical. 

 The mass transport pattern is the eastward movement of waters in the surface 

 layer out of Long Island Sound and the westward movement of bottom waters 

 into Long Island Sound from Block Island Sound (29) . The volume of fresh 

 water drainage controls the exchange and the annual total inflow of saline 

 water along the bottom is equal to 3.8 times the volume of water in the Sound 

 (29) . Although the tidal circulation pattern of surface and near surface 

 waters is known, relatively little information on deep current circulation is 

 avai 1 able. 



Limited exchange of water is believed to occur between the western 

 end of Long Island Sound and New York harbor. The net inflow from the East 

 River into western Long Island Sound has been estimated to be as high as 1,100 

 cubic meters per second (9,200 billion gallons per year), but recent studies 

 ( 11 ) indicate that this estimate may be too high by an order of magnitude. 

 The only other outflow is evaporation from the Sound to the atmosphere esti- 

 mated to be 630 billion gallons per year, slightly less than the precipitation 

 on the Sound. 



3.0 CLIMATOLOGY 



The unique features of the climate of the area surrounding Long 

 Island Sound are: four distinct seasons; a variety of precipitation types 

 but with little monthly variation in normal precipitation amounts; marked 

 temperature contrasts over short distances; and the maritime influence which 

 modifies the air masses that affect the area. The climate varies from one 

 location to another and from one year to another. There has been, for 

 example, a winter season with only 10 inches of snow in the northern part of 

 the region and another winter season with over 80 inches of snow in coastal 

 Connecticut; a record daily maximum temperature at a northern location of 

 10'4°F and a record February minimum near the coast of -24°F; Octobers with 

 almost no rainfall and a single October day in which nearly 10.5 inches of 

 rain fell at one location. 



