Figure 4. General view of model 



A 2-ft (horizontal) solid layer of fiber wave absorber was placed 

 around the inside perimeter of the model to dampen any wave energy that 

 might otherwise be reflected from the model walls. In addition, guide 

 vanes were placed along the wave generator sides in the flat pit area to en- 

 sure proper formation of the wave train incident to the model contours. 



As discussed previously, a fixed-bed model was constructed and a 

 tracer material was selected to qualitatively determine the deposition of 

 sediment in Noyo Cove and at the river mouth. Using the prototype sand 

 characteristics (median diameter, D50 = 0.25 mm, specific gravity = 2.69), 

 the tracer was chosen in accordance with the scaling of Noda (1972), 

 which indicates a relation or model law among the four basic scale ratios, 

 i.e., the horizontal scale, 1; the vertical scale, m; the sediment size ratio, 

 nD; and the relative specific weight ratio, n Y . These relations were deter- 

 mined experimentally using a wide range of conditions and bottom materi- 

 als. Although several types of movable-bed tracer materials were 

 available at WES, previous investigations (Giles and Chatham 1974, 

 Bottin and Chatham 1975) indicated that crushed coal tracer more nearly 

 represented the movement of prototype sand. Therefore, quantities of 

 crushed coal (specific gravity = 1.30; median diameter, D50 = 0.76 mm) 

 were selected for use as a tracer material. 



Chapter 2 The Model 



11 



