Characterizing Hydrologic and Geomorphic Processes in a Spring-Fed, Cold-Desert Headwater Stream

Science Center Objects

The role of natural versus human-influenced factors in sedimentation of Littlefield Creek, a small, high-desert creek in south-central Wyoming is currently unknown. In general, there is little empirical information about both hydrologic and geomorphic processes (together described as hydrogeomorphic) in these types of streams.  To develop a better understanding of  hydrogeomorphic processes, their timing, and role in creek sedimentation, a baseline data collection effort was begun in November 2018.

Littlefield Creek is a tributary to Muddy Creek and a genetic refuge for Colorado River cutthroat trout (Oncorhynchus clarkia pleuriticus), a species that has been extirpated from much of its native range. The upper reaches of Littlefield flow through erodible geologic formations  and the basin has a long tradition of cattle grazing. In past years, riparian BMPs have been implemented in an attempt to reduce sediment loading and increase bank stability. Additionally, the Wyoming Game and Fish has restored parts of the creek in to enhance fish habitat. However, since around 2015, fish and wildlife managers have continued to observe fine sediment accumulations on the bed of Littlefield Creek. These fine sediment accumulations reduce the quality of spawning habitat for cutthroat trout.

At first glance, Littlefield Creek appears to be small stream with limited capacity to move sediment or adjust its morphology (channel shape). However, an initial analysis has indicated that, despite its small size, the creek is very active, including recent meander cutoffs and a dynamic  system of beaver ponds. 

The goal of this project is to better understand the basic hydrology of this sample small stream, and assess the roles of natural-versus-human (land-use) factors in sedimentation of Littlefield Creek. In November of 2018, instruments were installed to measure stream stage and water temperature in 15-minute intervals. Time-lapse cameras were also set up to document hydrogeomorphic processes such as connection of the stream channel to its floodplain and the effects of snow and ice. In winter/spring 2020, passive sediment samplers will be installed in to sample suspended sediment loads, which will  be used to "fingerprint" sediment sources.

During the first winter of data collection, stage and photographic data showed snowdrifts damming the stream, which backed water up causing upstream flooding (see photos below). The stream eventually eroded the dam and the flooding receded. The snow dam flood caused a stage change that was 3 times higher than the spring snowmelt runoff.   Such basic documentation of hydrogeomorphic processes will be critical to understanding how sediment moves through this creek and how it may affect the quality of spawning habitat for native trout. 

These findings will be used by local mangers determine the most effective land-management and sediment mitigation strategies for this sensitive system.

Littlefield Creek Upper site

Littlefield Creek Upper site

(Credit: Jason Alexander, USGS WY-MT WSC. Public domain.)

Littlefield Creek Upper site

Littlefield Creek Upper site

(Credit: Jason Alexander, USGS WY-MT WSC. Public domain.)

Littlefield Creek Upper site

Littlefield Creek Upper site

(Credit: Jason Alexander, USGS WY-MT WSC. Public domain.)