Exercises to Examine a Ouachita River Reach Classification
In these virtual survey exercises on the Ouachita River near Pine Bluff, Arkansas, you will conduct a Rosgen Level II Classification. Rather than using laser levels, rods, and tape, ImageJ should be employed with the provided image and maps. The provided image is along a monumented cross section, and quantitative attributes will be measured and recorded to arrive at a classification. The provided maps will enable pattern and profile analysis.
Bed material assessment is critical for Level II classification. After virtually surveying the image and maps, you will conduct an abbreviated and virtual pebble count along the Reach. The method for pebble count assessment requires field data collection, implementing a systematic random method called the Wolman Pebble Count for Reachwide characterization, for which 100 samples are taken as a minimum. The gathered data come from a representative set of pools and riffles or steps.
The gathered bed material is analyzed relative to its passage through a sieve by measuring the intermediate axis. The intermediate axis is the middle length access, neither the shortest nor the longest length. Use ImageJ to make these measurements.
Instructions on how to use ImageJ were provided in Sections 1 and 2. Recall that you can use ImageJ Freehand and Polygon selections to measure area, or Straight line and Segmented sections to measure length.