Figure 1-12. Slumping of material at toe of dune during Dune Erosion 

 Test 2 



previous tests was therefore leveled and the material removed from the chan- 

 nel to take sand off the profile that had been moved there from the beach and 

 dune in previous tests. A portion of the beach and berm shoreward of the 

 capacitance wave gauges was removed, and a seawall was emplaced at 

 Station 1. This work took 8 hr and required several people and a small front 

 loader. Wave conditions were designed to be erosive, but not top over the 

 tank under the anticipated changed water levels. Figure 1-13 shows the 

 shoreward side of the seawall during emplacement, and Figure 1-14 shows 

 waves impacting the wall early in the test. 



ST 80: Seawall, Test 2 of 3 



Some sand was removed in front of the seawall to create a terraced profile 

 so that waves could attack the wall more directly than in the previous test. 

 The two seawall tests did not result in the erosion expected. 



ST90: Berm Flooding, Test 1 of 2 



The evening before this test, a dune and berm were constructed in front of 

 the seawall (Figure 1-15). The purpose of this test was to examine the pro- 

 cess of sand transport under erosive wave conditions when a flat area is flood- 

 ed. 



Chapter 1 Introduction to SUPERTANK 



19 



