Submitted to: Applied Engineering in Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 15, 1997
Publication Date: N/A
Interpretive Summary: Not the first formal report of this information.
Rock chutes, rock riprap on steep slopes, are used as grade control structures to safely conduct a water flow to a lower elevation. Previous studies have reported relationships to predict the highest stable unit discharge on the sloping face as a function of the material D50 and the bed slope. However, no studies report the riprap size required for stability at tthe chute outlet. The riprap size required for outlet stability was examined in two separate flumes and two field-scale structures. Angular riprap with D50 ranging from 52 to 278 mm was tested at slopes of 8, 10, 16.7, 22.2, 33.3, and 40%. For all tests, the D50 size predicted for stability on the sloping bed was also stable in the outlet reach of the chute. The tailwater elevation resulting from the outlet reach and downstream channel resistance was sufficient to prevent movement of the riprap in the outlet reach.