Snowmelt and rainfall runoff in burned and unburned catchments at the intermittent-persistent snow transition, Colorado Front Range

Winter snowmelt and summer monsoonal rains are the dominant sources for streamflow in the Colorado Front Range, and wildfire can greatly affect the hydrologic regime through which these inputs are delivered to the stream. However, the specific changes to the hydrologic processes that drive runoff production made by wildfire are not clearly understood. This research examines how wildfire affects the timing and magnitude of runoff production from snowmelt and rainfall by comparing four catchments in and near the High Park Fire area, two burned and two unburned, at the intermittent-persistent snow transition. Catchments were instrumented to monitor snow accumulation and ablation, rainfall, soil moisture, soil and air temperature, and streamflow response throughout water year 2015. These data were then utilized to determine the primary mechanisms of seasonal runoff generation and the magnitude of that runoff from each catchment. Runoff remained very low at all catchments during winter months. Spring snowmelt runoff in the form of lateral subsurface flow dominated catchment hydrographs for the water year. Following spring snowmelt, runoff production transitioned to a rainfall-dominated, drier summer period. During this time, limited infiltration excess overland flow was produced from high intensity rainfall events. Results of this research suggest that the loss of canopy cover due to wildfire may result in increased snowpack density and more intermittent snowpack throughout the winter months. Burned monitoring sites also maintained higher soil moisture than unburned sites, but this may be a function of site-specific variability rather than burning. Elevated soil moisture at burned sites did not translate to consistently higher runoff production. Both total runoff production and runoff ratios were highest in the high elevation unburned site with the highest snow persistence and the lowest elevation burned site with low snow persistence. During the one high intensity rain event that affected all catchments, burned catchments experienced an increase in discharge above baseflow of a greater magnitude than unburned sites. Overall, all catchments monitored showed site specific characteristics that defied easy classification but illustrated local variability in the hydrologic variables monitored.

Name thesis:degree_name

Master of Science (M.S.)

Level thesis:degree_level

Masters

Discipline thesis:degree_discipline

Ecosystem Science and Sustainability

Grantor dc:publisher

Colorado State University. Libraries

Year dc:date.issued

2016

Authors dc:creator

• Johnson, Adam, author
• Kampf, Stephanie, advisor
• Fassnacht, Steven, committee member
• Niemann, Jeffrey, committee member

• precipitation
• wildfire
• snow
• hydrology

Statement dc:rights

• Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright.

Language dc:language.iso

eng, English

Identifier URI

https://doi.org/10.25675/3.019000

OAI identifier oai:identifier

oai:mountainscholar.org:10217/173551