| Abstract: | ABSTRACT: Stability of vegetated and bare riprap revetments along a Sacramento River reach during the flood of record was assessed. Revetment damages resulting from the flood were identified using records provided by the U.S. Army Corps of Engineers and verified by contacts with local interests. Vegetation on revetments along a 35.6-mile reach was mapped using inspection records and stereo interpretation of aerial phoths taken shortly before and after the flood. A follow-up field inspection was conducted in September 1989. Revetment age, material, bank curvature, vegetation, and damage were mapped from a boat. Mapping results from both 1986 and 1989 were placed in a data base. About 70 percent of the bank line of the study reach was revetted. About two-thirds of the revetment was cobble; one-third was quarry stone. Revetment vegetation varied from none to large (> 50-inch diameter) cotton-woods. About 10 percent of the revetted bank line supported some type of woody vegetation. Damage rates for revetments supporting woody vegetation tended to be lower than for unvegetated revetments of the same age located on banks of similar curvature. Chisquared tests indicated damage rates were greater for older (pre-1950 construction) revetments, but were unable to detect differences based on vegetation or bank curvature. Research is needed to generate design criteria and construction techniques to allow routine use of woody plants in bank protection structures. |
