The Fluvial Geomorphology of the Upper Animas River Basin, Colorado
Abstract
<p>Recent research identifies mountain environments as especially
important for monitoring environmental changes related to both
global climate fluctuations and human activities. This dissertation
contributes to the numerous studies on human-Earth relationships
and addresses a lack of detailed knowledge of spatial relationships
in small mountainous headwater basins. The specific research
questions addressed herein include: Are the fluvial processes
within the watershed representative of the fluvial forms? Can
existing morphology classification schemes predict channel form
from collected raw data? How do the sediments within the headwater
streams reflect change through space? Data collected in the field
from streams within the Upper Animas River basin combined with
statistical techniques and the use of geographic information
science software allowed for the determination of a basin-scale
view of the fluvial forms and processes at work in this small
mountain watershed. A multivariate analysis of historical mining
effects on fluvial forms revealed a statistically significant
relationship between mining activities and channel entrenchment. An
investigation of the utility of existing channel classification
systems detailed the difficulty of classifying the morphology of
headwater streams and suggested that existing schemes should only
be used in this basin with caution. Data on the river sediment
landscape were calculated and mapped in order to investigate
downstream spatial patterns. Analyses determined a weak
relationship between channel roughness, sediment size, and sediment
shape as compared to drainage area due perhaps to the unique nature
of mountain streams and the extreme influence of coupled
hillslope-fluvial processes. Overall the rivers of this basin are
thought to be in a non-equilibrium state.</p>