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Abstract
We developed procedures for installing prefabricated trapezoidal flumes in deep (10 to 12 feet) drainage ditches to monitor hydrologic functions and provide gauge locations for sampling discharge. Flows from the instrumented basins were generally low, but the ditches were occasionally subject to high flows caused by rain events of 2 to 3 inches or more. These high flow events caused severe erosion and undercut the flumes when they were installed in the usual manner, washing two of the flumes downstream. Our modifications to the installation procedure included four main elements: (1) securing the flume to a concrete pad; (2) bolting entrenched wooden barriers to the flume’s inlet and outlet; (3) placing a plastic apron beneath the flume’s outflow opening; and (4) surrounding the flume with sandbags. Flumes installed using these elements have been significantly more stable and resistant to undercut and bank erosion than those we installed using the normal methods. As a result, the modified installation procedures have reduced necessary maintenance and data loss, making the additional cost and increased initial effort well worthwhile.
Citation
Harrison, Charles A.; O’Ney, Susan. 2002. Design and Modification of an Installation Method to Stabilize Small Trapezoidal Flumes in Drainage Ditches. Res. Note SE-11. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 4 p.
