3 Tests Conditions and 

 Procedures 



Selection of Test Conditions 



Still-water level 



Still-water levels (swl's) for wave action models are selected so that 

 the various wave-induced phenomena that are dependent on water depths 

 are accurately reproduced in the model. These phenomena include the re- 

 fraction of waves in the project area, the overtopping of structures by the 

 waves, the reflection of wave energy from various structures, and the 

 transmission of wave energy through porous structures. 



In most cases, it is desirable to select a model swl that closely approxi- 

 mates the higher water stages which normally occur in the prototype for 

 the following reasons: 



a.. The maximum amount of wave energy reaching a coastal area 

 normally occurs during the higher water phase of the local tidal 

 cycle. 



b. Most storms moving onshore are characteristically accompanied by 

 a higher water level due to wind tide and shoreward mass transport. 



c. The selection of a high swl helps minimize model scale effects due 

 to viscous bottom friction. 



d. When a high swl is selected, a model investigation tends to yield 

 more conservative results. 



The swl's of 0.0 and +7.0 ft were selected by CESPN for use during 

 model tests. The lower value (0.0 ft) represents mllw, and the upper value 

 (+7.0 ft) represents a monthly occurrence at the site. The 0.0-ft swl was 

 used during testing of riverine sediment patterns, and the +7.0-ft swl was 



Chapter 3 Tests Conditions and Procedures 



13 



