The 1982-90 sediment discharge from the South Fork Toutle River basin was less than 5 percent of the sediment discharge of the mainstem Toutle River for the same period. Partial records of sediment discharge were computed for storms in November 1980 measured at the South Fork Toutle River at Toutle (an ungaged bridge site). Daily sediment-discharge records at the South Fork Toutle River at Camp 12 are available for May 22, 1981, to September 30, 1990 ( fig. 36 ). Intermittent values of daily sediment discharge that were available for water year 1981 are plotted as solid circles. The river bank, with the existing gage house, collapsed into the storm flow of December 1981. The gage house was replaced in January 1982.
A flood-warning gaging station was established at the South Fork Toutle River above Herrington Creek near Spotted Buck Mountain in 1980. Rapid migration of the braided channel frustrated attempts to maintain a stage-discharge relation at the site. Sediment-discharge measurements were made at the site during 1981 and 1982 ( fig. 37 ).
