2. Comparison of RIST to Other Sediment Transport Studies 



(a) Radionuclide Systems . In addition to investigation in the 

 United States, radionuclide tracing technology is actively pursued by 

 the French, Japanese, British, and Australians. Rather than review all 

 of the reported studies, representative studies have been selected for 

 description and consequent comparison to the RIST program. 



Perhaps the best known of the British studies was reported by 

 Crickmore and Lean (1962) . This study was carried out in laboratory 

 flumes with the goal of modeling sediment movement and providing a 

 formula for quantifying results. Geiger-Miiller tubes, buried in the 

 flume, were used to detect radioactive sand moving in ripples over the 

 detectors. Results of the studies are presented as a formula which 

 provides the quantity of sediment moving as deduced by the time- 

 integration method. 



Studies by the French (Courtois and Monaco, 1969) are similar to 

 the field programs of the British, Australians, and Japanese. These 

 generally involve a sled-type detector carrying one or two scintillation 

 detectors. In the French program, the sled carried two scintillation 

 detectors with a sensitivity of 1 microcurie per square meter. Sand 

 grains were tagged by the adsorption and consequent oxidation of 

 chromium-51 on the surface of the grains; 10 pounds of sand were tagged 

 with a total of 10 curies. Radiation was recorded on a strip chart 

 and later by digital printout. The test was carried out on the French 

 Mediterranean Coast in water 12 to 15 feet deep. All surveys of sedi- 

 ment dispersion from a point source were seaward of the breaker zone. 

 Location of the vessels during the surveys was obtained by the cutoff 

 angle technique described previously; angles were determined at 1-minute 

 intervals. No information is provided with regard to the number of 

 profiles or the length of time involved in each survey; however, the 

 contoured area covers a rectangle 360 by 1,200 feet. Three surveys were 

 conducted over a period of 1 month. Qualitative and quantitative results 

 of the study are reported. Qualitative results are provided by a map 

 which shows the dispersion of the tagged material during the survey. 

 A quantitative analysis of the survey was made by using a radiation- 

 material balance to determine depth of burial (correlated with some core 

 data) which was then coupled to the displacement of the computed center 

 of gravity of the moving mass of tagged sand. 



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

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

 Channel (Hart, 1969). This study in the Galveston, Texas, area is the 

 most recent research in sediment tracing reported by WES and is one of 

 the most up-to-date of the radionuclide tracer studies in the United 

 States. It is also representative of several previous WES programs. 

 The isotope reported used was gold- 198 which was mixed in solution with 

 sediment at the site. Tagging occurred by simple adsorption by fine- 

 grained sands. About 4 cubic feet of sediment were treated with a total 



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