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3 Test Conditions and 

 Procedures 



Selection of Test Conditions 



still-water level \ 



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

 wave-induced phenomena that are dependent on water depths are accurately 

 reproduced in the model. These phenomena include refraction of waves in the 

 project area, overtopping of structures by waves, reflection of wave energy 

 from various stiuctures, and transmission of wave energy through porous 

 structures. 



In most cases, for the following reasons, it is desirable to select a model 

 swl that closely approximates the higher water stages that normally occur in 

 the prototype: 



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 ti-ansport. 



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 Maine coast experiences semidiurnal tides, which are two high and two 

 low tides each lunar day (approximately 24 hr, 50 min). Tidal data represen- 

 tative of tiie Camp EUis Beach site are shown below (USAED, New England 

 1992): 



Chapter 3 Test Conditions and Procedures 



