T.M. No. 10 - January 1965 



Experimental Study of Longshore Currents on a Plane Beach 

 by C. J. Galvin, Jr. and P. S. Eagleson 



This investigat i-on deals with experimental description of 

 longshore currents and analytical prediction of longshore current 

 velocity. The experimental phase includes measurements, under con- 

 trolled laboratory conditions, of phenomena associated with longshore 

 currents flowing on a smooth, plane beach. The analytical phase in- 

 cludes development of an empirical relation between longshore current 

 velocity and wave conditions at breaking, an order-of-magnitude 

 analysis of energy in the surf zone, and an examination of equations 

 of motion for longshore currents. The empirical relation for predict- 

 ing approximate value of mean velocity of uniform longshore currents 

 agrees with some sets of field and laboratory data. 



T.M. No. I I - February 1965 



Behavior of Beach Fill and Borrow Area at Seaside Park, Bridgeport , 

 Connecticut by William H. Vesper 



Comparative survey and sand sampling data are analyzed to 

 determine the behavior of beach fill placed on the beach from an 

 offshore borrow source. Over a 5-year period subsequent to initial 

 placement, volume losses averaging about 14,000 cubic yards per year 

 from the beach zone above MLW are nearly equalled by volume gains 

 in the underwater zone of the profile, with only a comparatively 

 small net volume C8,400 cubic yards for the 5-year period) indicated 

 as net loss from the fill area. The borrow area, about 1,200 feet 

 offshore, was concluded to be sufficiently distant to preclude in- 

 ducement of offshore loss. Annual cost of providing and maintaining 

 the authorized beach protection at Seaside Park is estimated at $3.35 

 per linear foot of shore protected. 



T.M. No. 12 - March 1965 



Source and Distribution of Sediments at Brunswick Harbor & Vicinity , 

 Georgia by James Neiheisel 



Distribution patterns of bottom sediment in Brunswick tHarbor 

 reflect long-term hydrodynamic response and generally correlate 

 with dynamic factors affecting sedimentation. Certain diagnostic 

 minerals reflect the source and are used as "natural tracers" to 

 delineate direction of sediment movement. Analysis of sediment 

 parameters enables interpretation of sediment transport direction. 

 Results indicate present shoaling is related to source materials in 

 Altamaha River, and that sediments are introduced into the harbor 

 through the tidal inlet between the barrier islands and also through 

 MacKay River during greater than average discharge rates of the 

 Altamaha River. 



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