TRACING LITTORAL SAND MOVEMENT: RADIOISOTOPIC SAND TRACER (RIST) STUDY 

 Progress July 1968 - February 1969 



Section I. INTRODUCTION 



1. Background 



In 1966, the U. S. Army Coastal Engineering Research Center 

 (CERC) , in cooperation with the Atomic Energy Commission (AEC) , initiated 

 a Radioisotopic Sand Tracer (RIST) Investigation of Littoral Transport 

 around Point Conception, California. Program objectives were: (a) a 

 study and selection of suitable radioisotope (s) ; (b) development of radi- 

 ation detection equipment capable of operating on the beach and in the 

 nearshore waters to depths of 100 feet; and (c) trace the movement of 

 tagged sand in the littoral zone. 



A major part of the development of hardware and tagging techniques 

 was done by AEC's Oak Ridge National Laboratory (ORNL) at Oak Ridge, 

 Tennessee. Other direct participants in the study in fiscal year 1969 

 were U. S. Navy Pacific Missile Range; U. S. Air Force First Strategic 

 Aerospace Division; U. S. Army Engineer District Office in Los Angeles; 

 U. S. Army Mobility Command; National Aeronautics and Space Administra- 

 tion; and the Division of Water Resources, State of California. 



Results of this program through June 1968 have been summarized 

 previously (Duane and Judge, 1969; Acree, et al, 1969). This paper 

 is a report on progress of the program since June 1968, especially on 

 various aspects of sediment movement on the beach and nearshore zone as 

 depicted by experiments at Surf, California, during September-October 

 1968, and February 1969 (Figure 1). 



Since 1968, results of several different field experiments in 

 nuclide tracers have been published. Courtois and Monaco (1969) report 

 on tests carried out along the French Mediterranean Coast in water 12 to 

 15 feet deep, using chromium 51 and iridium 95 as the tagging isotopes. 

 The French experiment established sediment dispersal patterns over a 

 period of 1 month. 



The U. S. Army Engineer Waterways Experiment Station (WES), 

 Vicksburg, Mississippi, recently completed a survey in the Houston Ship 

 Channel (Hart, 1969). The isotope, gold-198, was mixed in solution with 

 sediment at the site. The experiment lasted about 2 weeks. 



Several studies using fluorescent tracers have been reported re- 

 cently. Kennedy and Kouba (1968) in a U. S. Geological Survey (USGS) 

 open- file report, present results of studies in sediment transport at 

 Clear Creek, Colorado. At the University of Florida, the Department 

 of Coastal and Oceanographic Engineering has been experimenting with 



