Spatial and temporal variability in stream sediment loads using examples from the Gros Ventre Range, Wyoming, USA

Abstract

Sediment transport rates (dissolved, suspended, and bedload) measured over the course of several years are reported for two streams in the Gros Ventre Mountain range in western Wyoming, USA: Little Granite and Cache Creeks. Both streams drain watersheds that are in relatively pristine environments. The sites are about 20km apart, have runoff dominated by snowmelt and are underlain by a similar geological setting, suggesting that sediment supply and rates of transport in the two watersheds may be comparable. Yet, estimated sediment yields for the two sites appear substantially different. On average, sediment load per unit watershed area was about 40% greater at Little Granite Creek than Cache Creek, with larger differences during wetter years. Moreover, while there were differences for all components of the sediment load, suspended, and bedload fractions showed the most noteworthy contrast where nearly three times more material was exported from Little Granite Creek on an annual basis. Speculatively, this is attributed to contributions of sediment from several chronic sources in the Little Granite Creek watershed.

Citation

Ryan, Sandra E.; Dixon, Mark K. 2007. Spatial and temporal variability in stream sediment loads using examples from the Gros Ventre Range, Wyoming, USA. In: Habersack, H.; Piegay, H.; Rinaldi, M., editors. Gravel bed rivers VI: From process understanding to river restoration. Developments in Earth Surface Processes. 11: 387-407.