Tanana River Monitoring And Research Program PDF Download

To determine if available data are useful in identifying the characteristics that contributed to erodibility of the banks along two reaches of the Tanana River, existing data on bank vegetation, soils, sediments, and permafrost were examined. Because these data were general and not collected for the purpose of site-specific analysis, an analytical approach was simple and did not include any statistical tests. The data were visually compared to the locations and estimated amounts of historical recession to evaluate if any relationships were obvious. The results of this analysis showed no useful relationships. Vegetation was similar in eroded and uneroded areas and its distribution did not show any obvious relationship to the locations of bank recession. Surface sediments and soils in the eroded and uneroded areas had little, if any, effect on bank erodibility because the river erodes the bank over its entire depth, which is well below this surface zone. The subsurface sediment from eroded and uneroded wells and along transects wtih high and low measured recession was similar. Permafrost occurrences are about equal in eroded and uneroded sites, although it appears that recession can be higher where permafrost is common than where it is absent. In most cases the existing data are either too general or not properly located to be useful in anticipating future locations of bank erosion. In order to predict future erosion, a field project should be initiated to evaluate the influences of bank characteristics and hydraulic forces on bank erosion rates.