PROGRESS REPORTS ON RESEARCH SPONSORED BY 

 THB BEACH EROSION BOARD 



Compiled by Thorndike Saville, Jr., Research Division 

 Beach Erosion Board 



Summaries of progress made during fiscal year 1961 (i.e. to June 

 30, 1961) on the several research contracts in force between universities 

 or other institutions and the Beach Brosion Board, together with brief 

 statements as to the status of some research projects being prosecuted 

 in the laboratory of the Beach Erosion Board, are presented below. These 

 summaries supplement and continue those contained in prior issues of the 

 Bulletin. 



I. University of California, Contract DA-49-055-eng-8. Sources of 

 Beach Sand . 



Seasonal sampling of the eighteen beaches in the San Francisco area 

 was continued. The beaches between Russian River and the Oregon State 

 line were also occupied several times during the year, so that the three 

 critical times of the year (late summer, early winter, and late spring) 

 might be represented. Reports on this work are underway. A rather exten- 

 sive study was made of the feasibility of using the Frantz electro-dynamic 

 separator for segregating beach sands into different mineral groups on the 

 basis of their magnetic susceptibility. Both grain size and specific 

 gravity have also proved to be important factors, and accordingly fhe 

 development of proper techniques has been difficult, although considerable 

 progress has been made. 



II. Massachusetts Institute of Technology, Contract DA-49-055*»eng-16 . 

 Sorting of Beach Sand by Waves . 



A report "Equilibrium Characteristics of Sand Beaches in the Offshore 

 Zone" has been prepared (Technical Memorandum No. 126 of the Beach Erosion 

 Board). The report describes a theoretical and experimental investigation 

 of equilibrium profiles and sediment sorting in the offshore zone, designed 

 to test the applicability of existing idealized theories to the prediction 

 of equilibrium characteristics of laboratory sand beaches. Two different 

 sediment motion equilibrium criteria are considered; one in which the 

 moments on a stationary particle are at equilibrium and one in which the 

 particle is oscillating with no net motion. Results indicate existing 

 theories provide good quantitative prediction of the seaward limit of 

 profile modification and whether a given beach will build or erode under 

 action of a given incident wave. Quantitative prediction of profile shape 

 is good only near the offshore extreme of profile modification. Sorting 

 experiments support qualitative theoretical predictions of increase in 

 size sorting in the onshore direction and tendency toward formation of 



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