Century-scale channel changes for the Salt River, central Arizona-Phoenix.

Study how the geomorphology of the Salt River channel has changed over the last
100 years and how factors such as the damming of the Salt and Verde Rivers and
gravel mining operations have contributed to these changes. For more than 1,000 years there has been a city on the banks of the Salt and Gila
Rivers in the vicinity of what is now Phoenix. The course of natural processes as
embodied by the river have interacted with the course of human events as evidenced
by the city, each exerting influence on the other. The myriad of tangled connections
between the natural and social systems has inevitably altered each of them, so that
understanding of one without understanding of the other is incomplete. Within the
last 100 years, intensive technological development of the river resources, its
space, water, materials, and biotic complements, has radically altered the natural
processes and forms of the river. At the same time, the river has influenced
development of the city, sometimes as a resource such as recreational space, and
sometimes as a hazard such as flooding. This constantly changing fluvial system,
integrating natural and artificial influences, is the foundation for the primary
riparian ecosystems of the region. The research questions of this project are: (1) What has been the nature of change
in the geomorphic/riparian system, and how have human and natural factors controlled
the distribution and intensity of the change over the past century? (2) Why does the
river have its present geomorphic/riparian configuration, and how stable is that
arrangement from geomorphic, hydrologic, and geographic perspectives? and (3) How
does the river respond to ongoing changes in the spatial arrangement of human
activities and attending technological impacts? This project promises improved understanding of the dynamics of dryland rivers,
especially how and why they change under the influence of urban development. The
research also promises to provide an integrating factor in the CAP LTER effort,
because the river integrates the influences of hydrologic, geomorphic, biotic, and
human technological systems. The research will provide a repeatable quantitative
approach to assessing the changes in the river and as it continues its
millennium-long connection between natural and social systems.