You are here:
STREAM CHANNEL SEDIMENT CONDITIONS IN THE SOUTH FORK SALMON RIVER, IDAHO, PROGRESS REPORT IV, JUNE 1974
Description:
The purpose of the South Fork Salmon River (17060208) studies is to determine the condition of the aquatic environment and provide measures needed to maintain or enhance this environment. Prior to 1965, the South Fork Salmon River steadily degraded in quality, due to acceleration of incoming fine sediment from disturbed lands. Most of the degradation occurred between 1962 and 1965. During 1952-1965, the River was incapable of discharging the accrued bedload sediment as fast as it was being recruited. This period corresponded with the increase in logging and road construction activities. During 1966-1972, the South Fork discharged bedload sediment faster than it was being recruited. During this period, there was decreased logging and road construction, finalizing in a complete non-log moratorium. During 1973, monitoring areas continued to show improvement, but the river stations did not. Factors such as an extremely low waterflow year (1973) resulting in low energy for moving sediment, and pools acting as sediment traps even during fairly high flows could be the reason for the increase of channel fine sediment readings. In Progress Report II, it was predicted that without any large storms and no additional logging or other conditions causing disturbed lands, along with rehabilitation of the present road system and logged areas, the river should return to near-natural status within the next decade. Even though all the 1973 information does not follow this trend, the author believes that the information does not warrant any changes in past predictions of the rivers return to near-natural conditions. Platts, W.S. June 1974. U.S. Forest Service. 38 pp.