Appendix A. The fixed-bed beach was constructed by accurately installing
bottom elevation templates that are fixed to the floor of the wave basin. The
space between the templates was filled with general-purpose sand and
compacted, and then capped with a concrete veneer approximately 0.1 m thick.
The surface of the concrete was broom finished to simulate the natural roughness
of sand. Figure B-1, Appendix B, shows the concrete beach from the
downstream end of the facility. Small longshore variations in beach elevation
can have a significant influence on longshore current patterns (Putrevu, Oltman-
Shay, and Svendsen 1995). Therefore, the beach was designed and carefully
constructed with straight and parallel depth contours and a high degree of
accuracy (estimated vertical variation of +2 mm).
100
90
80
70
60
50
40
30
20
10
0
10
1
0.1
0.01
Grain Size (mm)
Figure 3.
Grain size distribution of sand used in initial experiments
Sand moveable bed
One of the purposes of the LSTF is to quantify the effect of sediment size on
longshore sediment transport. The facility was designed so that the moveable-
bed beach could be constructed with various sand sizes. The first phase of
sediment transport experiments is being conducted on a moveable-bed beach
consisting of approximately 125 m3 of very well-sorted quartz sand having a
median grain size, D50 = 0.15 mm (Figure 3). This is considered fine-grained
sand according to the Wentworth classification system. An additional 25 m3 of
sand is stored outside of the facility for future use.
At the beginning of the sediment transport experiments, the beach profile
was graded to have the initial profile shape shown in Figure 4. This initial shape
was determined based on results obtained from preliminary moveable-bed
5
Chapter 2
Overview of the Laboratory Facility
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