OBSERVATION OF THE SEDIMENT GRAIN SIZE DISTRIBUTION CHANGE ALONG A CREEK PROFILE IN INDIANA, USA

As water moves downstream, it carries sediments that become sorted and rounded. The purpose of this research project, which is a requirement for an upper level geology course, is to determine the water content of soil, overall composition of the sediment (gravel, sand, etc.), and grain size changes (if it does change) along a river profile, using a creek that runs through the Indiana University-Purdue University Fort Wayne (IPFW) campus. In the 2014 Fall semester, grain size distribution analysis was performed on fourteen soil samples collected along the length of the creek. Fourteen soil samples were also collected from same sites in the 2015 Spring semester. The data indicates that water content and grain size distribution vary along the creek profile. Certain samples had significantly lower water content than others, that, when examined more closely, revealed a different soil profile containing less silt-clays and higher sand-gravel components. The average water content for all samples in the Fall of 2014 is 21.87% with minimal variation; this is closely mimicked in the Spring 2015 samples with average water content of 25.74% again with minimal variation. Although the samples were taken from the same locations, there are differences in soil composition. The soils range from coarse to fine grained sand, but are generally fine-grained. Knowing the cause(s) of the finning of the sediments downstream in the creek may help in managing the stream and probably other rivers in northern Indiana. This is an ongoing research and new data will be presented.