%0 Journal Article
%T An Evaluation of Data Collected by Middle School and College-Level Students in Stream Channel Geomorphic Assessment
%A Martin D. Lafrenz
%J Geography Journal
%D 2013
%I Hindawi Publishing Corporation
%R 10.1155/2013/898164
%X This project tested the accuracy and repeatability of geomorphic stream channel assessments conducted by two different middle school classes from the Walt Morey Middle School in Troutdale, OR and college students from Portland State University in Portland, OR. Each group surveyed the same three cross-sections in Fairview Creek, a tributary to the Lower Columbia River, in order to assess stream channel geometry, discharge, composition of the bed material, and water quality. The three student groups were all able to accurately document the stream channel geometry, including stream width and mean depth, indicating that these data can be successfully collected by volunteers of various ages. However, stream velocity obtained using the float method was consistently overestimated leading to a biased calculation of discharge, and the low precision of the measurements did not allow for a correction of the bias. The median particle size of the bed material determined by a pebble count was also overestimated by each group, but the low precision also negated the possibility of correcting the estimate. The stored fine sediment in the bed was underestimated by each group and again with low precision. The temperature, pH, and conductivity measured with a calibrated multimeter were accurate and precise for all groups. 1. Introduction Watershed-scale models are increasingly being used to assist researchers and managers with determining the flux of sediment and nutrients between land and stream channels [1, 2]. Models are useful as the sheer magnitude of stream channel degradation, particularly in urban areas [3], by far exceeds the management resources required to assess and monitor changes in every impaired stream reach. Most sediment models use landscape variables, which can be derived from a Geographic Information System (GIS), to predict sediment delivery to a stream, and a few sediment models have incorporated in-channel sediment transport equations to further refine the ultimate sediment delivery volumes [4]. However, it is problematic to model the sediment contribution of the stream channel itself at the watershed scale because the inherent spatial and temporal heterogeneity of in-channel stored sediment is difficult to monitor remotely. Given that stream banks have been shown to contribute 80% [5] to 96% [6] of the total instream sediment load, fluvial geomorphologists and land resource managers have come to realize the pressing need for in situ gathered stream channel information in order to assess the impact of various land use practices on aquatic habitat and
%U http://www.hindawi.com/journals/geography/2013/898164/