| Landscape Surface Changes USGS Navajo Nation Studies |
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USGS Navajo Nation Studies Map of Study Area Bedrock Mapping Surficial Mapping Land Surface Changes Vegetation Drought Conditions 1999-2005 Traditional Knowledge and the Native Perspective Project Participants Web Links Selected References Publications & Presentations |
We will produce documentation of changes in local landscape conditions, the distribution
of shrubs and juniper, and the history of arroyo incision. McFadden and McAuliffe (1997)
suggest that changes in precipitation, rather than land use, have been largely responsible
for arroyo formation, because of the highly erodible nature of regional bedrock, and its
sensitivity to minor climatic change. The landscape of the Navajo Nation is characterized
by ephemeral streams that have incised easily eroded fine-grained valley-fill, and highly
erodible soft bedrock lithologies, such as the Bidahochi and Chinle Formations. This makes
the region especially sensitive to short-term variations in precipitation and temperature.
Preliminary work suggests that local erosion by alluvial processes is dominated by overland
flow. Although processes that contribute to arroyo incision are complex, it is most likely
attributed to changes in hillslope vegetation. Perturbations in plant cover affect discharge
of water and sediment from hillslopes, hydraulic roughness, and the amount of surface
sediment traps (Bull, 1997). Arroyo formation can result from precipitation changes or
changes in grazing practices that we will decipher by examination of multi-date sets of
aerial and historic photos to determine the temporal relation of surface change to land use
and climatic fluctuations, and by monitoring sites selected by preliminary mapping.
Monitoring and remote sensing can provide an important link between the geologic record and
specific atmospheric processes that are required to understand the effects of climate
change on geomorphic processes that govern landscape mobility and stability hydraulic roughness. |
 Left: Arroyo east of Satan Butte, near Greasewood, AZ Right: Eroding Parabolic Dune, south of Pyramid Butte, AZ |
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U.S.
Department of the Interior - U.S.
Geological Survey - Geology
Discipline |
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