LABORATORY EFFECTS IN BEACH STUDIES 
Volume V. Movable-Bed Experiment With H,/L, = 0.039 
by 
Charles B. Chesnutt and Robert P. Stafford 
I. INTRODUCTION 
1. Background. 
Wave reflection has been shown to vary significantly as a movable-bed 
profile changes from an initial planar slope to one closer to equilibrium 
(Chesnutt and Galvin, 1974). Wave reflection from a profile of a given 
slope is expected to decrease with increasing wave steepness. 
The Laboratory Effects in Beach Studies (LEBS) project was initiated 
at the Coastal Engineering Research Center (CERC) in 1966 to investigate 
the causes of wave height variability and other problems associated with 
movable-bed coastal engineering laboratory studies. Ten movable-bed lab- 
oratory experiments were conducted from 1970 to 1972 in the CERC Shore 
Processes Test Basin (SPTB) to measure the variation in reflection as the 
profile developed toward equilibrium. This report (Vol. V) discusses the 
experiment conducted with H/o = 0.039; Volumes II, III, and IV (Chesnutt 
and Stafford, 1977a, 1977b, 1977c) discussed the experiments conducted 
with H,/Lo = 0.021. The other four experiments are covered in Volumes VI 
and VII, part of a series of eight reports on LEBS. Volume I of the series 
(Stafford and Chesnutt, 1977) discusses the contents and primary purposes 
of these reports. 
Volumes II and III in this series (Chesnutt and Stafford, 1977a, 1977b) 
describe four experiments with initial slopes of 0.10 and wave steepness 
of 0.021, which led directly to the experiment described in this report. 
Those experiments were conducted primarily to (a) relate the variation of 
wave height to the variation in wave reflection caused by changes in the 
movable-bed profile, and (b) define the equilibrium profile shape, at 
which point it was assumed that the wave height variability would be sig- 
nificantly reduced. 
The experiment discussed in this study had an initial slope of 0.10, 
but wave steepness was increased from 0.021 to 0.039, in an attempt to 
determine how much the wave reflection and the reflection variability 
would be reduced by increased wave steepness. 
Experiment 72D-06 (Vol. IV; Chesnutt and Stafford, 1977c) was con- 
ducted concurrently with this experiment. Results will also be compared 
with that experiment, which had a wave period of 1.90 seconds, but had 
an initial slope of 0.05. 
