Abstract

The Rock Island Office, Corps of Engineers, U.S. Army has since 1940 carried on an extensive study of the suspended sediment of many streams which lie in its district. The district embraces parts of Iowa, Illinois, Wisconsin and Missouri and has its main office in Rock Island, Illinois. In 1938 an ingenious sampler was developed but it proved too complicated for widespread use and it was never utilized at any permanent station. The Rock Island Simplified Time-Integrating Sampler was developed in 1939 and is still used today on some of the stations. Constant study during the last five years has resulted in the improvement of this model. The depth-integrating method of sampling is used and samples are taken at least once a day at thalweg. The samples are shipped to the central laboratory at Rock Island, Illinois where they are analyzed for total sediment content. Some of the samples are analyzed for size grade distribution of the sediment by using the decantation method. The development of this sediment program has made available many data for use in connection with various engineering projects within the district.

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