Skip to Main Content
Impacts of wildfire on runoff and sediment loads at Little Granite Creek, western WyomingAuthor(s): Sandra E. Ryan; Kathleen A. Dwire; Mark K. Dixon
Source: Geomorphology. 129: 113-130.
Publication Series: Scientific Journal (JRNL)
Station: Rocky Mountain Research Station
Download Publication (1.0 MB)
DescriptionBaseline data on rates of sediment transport provide useful information on the inherent variability of stream processes and may be used to assess departure in channel form or process from disturbances. In August 2000, wildfire burned portions of the Little Granite Creek watershed near Bondurant, WY where bedload and suspended sediment measurements had been collected during 13 previous runoff seasons. This presented an opportunity to quantify increases in sediment loads associated with a large-scale natural disturbance. The first three years post-fire were warm and dry, with low snowpacks and few significant summer storms. Despite relatively low flows during the first runoff season, the estimated sediment load was about five times that predicted from regression of data from the pre-burn record. Increased sediment loading occurred during the rising limb and peak of snowmelt (54%) and during the few summer storms (44%). While high during the first post-fire year, total annual sediment yield decreased during the next two years, indicating an eventual return to baseline levels. The results from this sediment monitoring lacked some of the more dramatic responses that have been observed in other watersheds following fire. In other environments, moderate-to-high intensity rainstorms caused significant flooding, widespread debris flows and channel incision and aggradation. A few moderate intensity storms (b2 year recurrence interval) occurred in the Little Granite Creek watershed, but they did not trigger this type of response. Instead, ash and charcoal rich discharges (herein described as "blackwater flows") and heavily sediment laden flows were observed without physical evidence of debris flows, as defined by channel incision into previously unchanneled areas. Speculatively, the sedimentation pattern and geomorphic response in Little Granite Creek may be fairly typical of stream responses to wildfire during times of continued drought and in the absence of widespread, significant rainfall, representing one type of response on a continuum of effects following wildfire.
- You may send email to email@example.com to request a hard copy of this publication.
- (Please specify exactly which publication you are requesting and your mailing address.)
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
CitationRyan, Sandra E.; Dwire, Kathleen A.; Dixon, Mark K. 2011. Impacts of wildfire on runoff and sediment loads at Little Granite Creek, western Wyoming. Geomorphology. 129: 113-130.
Keywordsfire effects, runoff, sediment, suspended sediment concentration, Little Granite Creek
- Connectivity of post-fire runoff and sediment from nested hillslopes and watersheds
- Spatial and temporal variability in stream sediment loads using examples from the Gros Ventre Range, Wyoming, USA
- Post-disturbance sediment recovery: Implications for watershed resilience
XML: View XML