Figure 1-9. 



Servicing of acoustic-Doppler current profilers between wave 

 runs 



ST_50: Dune erosion. Test 1 of 2 



A dune was constructed and subjected to short-period high waves to cause 

 erosion. The dune was not compacted. The water level was lower at the be- 

 ginning of the test and higher at the end to provide data on erosion by runup 

 and by direct wave impact. Figure 1-10 shows the dune configuration at the 

 start of the test, and Figure 1-11 shows failure of the dune after approximately 

 90 min of wave action. The cross-section views of the dune face and failure 

 line are indicators of good two-dimensionality of the hydrodynamic and sedi- 

 ment transport processes. 



ST 60: Dune erosion. Test 2 of 2 



A dune of approximately the same configuration as in the previous test 

 was constructed and compacted with a vibrator for approximately 2 hr. 

 Figure 1-12 shows the dune and dune toe just after major slumping. 



ST 70: Seawall, Test 1 of 3 



The profile was considered "sand rich" at this time, because most of the 

 previous tests had removed sand from the upper portion of the profile and 

 deposited it offshore. The break-point bar that had formed at Station 9 in 



Chapter 1 Introduction to SUPERTANK 



17 



