T.M. No. I 12 - May 1959 



The Propagation of Tidal Waves into Channels of Gradually Varying 

 Cross-Section (Effect of a Frictional Resistance Over the Bed) 

 by Paul Perroud 



The effect of frictional resistance over the bed on the propa- 

 gation of long .waves of small amplitude into a shallow converging 

 channel is evaluated mathematically for the cases of a channel of 

 uniform depth with gradually varying breadth and a channel of uni- 

 form breadth and gradually varying depth. Simple solut.ions are 

 found for the amplitude, celerity and length of the wave which in 

 some cases could describe the phenomenon of wave propagation into 

 natural estuaries to a first approximation. 



T.M. No. I 15 - June 1959 



Behavior of Beach Fill at Virginia Beach, Virginia by G. M. Watts 



Comparative survey and sand sample data are analyzed to deter- 

 mine the behavior of beach fill placed to restore and nourish the 

 beach at this resort location. Initial restoration was accomplished 

 in 1952-1953, and sand nourishment was added periodically thereafter, 

 Conclusions are drawn that the restored beach has been virtually 

 stabilized by annual nourishment at the rate of about 2.5 cubic 

 yards per lineal foot of shore. Periodic nourishment at this rate 

 is concluded to be the most economical method of maintaining 

 required beach dimensions. 



T.M. No. I 14 - June 1959 



Laboratory Study of the Effect of Groins on the Rate of Littoral 

 Transport: Equipment Development and Initial Tests by R. P. Savage. 



Waves are generated to impinge obi iquely on a sand beach in an 

 outdoor wave test basin. Alongshore movement of sand due to wave 

 action, both with and without groins, is measured; procedures and 

 equipment for trapping, measuring and transporting entrapped sand 

 to the updrift end of the beach are described in detail. Test 

 results, such as cumulative weight of sand movement relative to 

 test duration, relative weight of sand trapped in different pro- 

 file zones and physical changes to profile and bottom contours, 

 are graphically presented. The rate of sand movement relative 

 to applied wave energy is compared with values obtained by other 

 investigators. Rates determined from small-scale laboratory data 

 fall below an extrapolated curve derived from data from actual 

 field tests. No positive conclusions are drawn, and further 

 testing is underway. 



33 



