Civil Engineering ETDs

Publication Date

Summer 7-15-2020

Abstract

Wildfire causes severe physical changes to watersheds, which then leads to geomorphic changes in the burned watersheds. In New Mexico and the southwestern U.S., flooding is a common response after a wildfire, due to higher water runoff from the hillslopes and sediment erosion rates. These flood events change the erosion and deposition characteristics of a stream, which can result in the deposition of a large amount of sediment near the communities living downstream. The objective of this research was to analyze and compare post-fire geomorphic stream response caused by six different wildfires in New Mexico with the goal to create a conceptual channel evolution model for 1st, and 3rd order streams post-wildfire in semi-arid environments. This was accomplished through a combination of fieldwork and historical spatial analysis of the active channel width pre and post wildfire conditions. This study compared the post-fire geomorphic responses between 1st and 3rd order streams for six different wildfires that burned in New Mexico once and the results were used to generate a conceptual model of these changes. The research results suggest a large variety in individual wildfire-caused geomorphic changes in active channel width, after wildfires. However, a trend of increasing active channel width was observed in 9 out of 12 streams within the first four years after a wildfire. Also, four years after the fire, the active channel width percent increase of all 1st order streams was larger than the increase of all 3rd order streams.

Keywords

Geomorphology, Wildfires, Channel evolution

Document Type

Thesis

Language

English

Degree Name

Civil Engineering

Level of Degree

Masters

Department Name

Civil Engineering

First Committee Member (Chair)

Mark Stone

Second Committee Member

Jose Cerrato

Third Committee Member

Becky Bixby

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