18
Geomorphology and Policy for
Restoration of Impounded American
Rivers: What is 'Natural?'
William L. Graf
Department of Geography, Arizona State University
ABSTRACT
Geomorphology as a natural science is returning to its roots of a close association with
environmental resource management and public policy. The science, after an insular
period emphasizing mostly basic research questions, has graduated to a more mature phase
wherein there is a new emphasis on application of established theory to address issues of
social concern. In this new phase, geomorphology must become more interactive with
other environmental sciences, and must establish socially relevant paradigms for research
and teaching. An example of geomorphology's new directions is the research activity in
fluvial geomorphology directed to the restoration of rivers downstream from American
dams. The era for construction of large dams is over in the United States, leaving the
nation with a fragmented river system and new social values that emphasize restoration
through the Federal Power Act, Endangered Species Act, and Safety of Dams Act. The
nation's rivers are now divided into segments, with some parts dominated by the direct
effects of dams, some by indirect effects, and some in a preserved, unaffected state. To
enhance river restoration, policymakers are focusing on dams, modifying them, changing
their operating rules (on the Colorado, Trinity, Gunnison, and Kissimmee rivers), and in
some cases removing them (on the Elwha, Kennebec, Milwaukee, and Gila rivers). The
objective of these measures is to return the downstream landscape to its original, natural
condition, yet geomorphic and ecologic changes related to the dams are not completely
reversible. The issue of what is natural, and how closely restored systems can approximate
natural conditions downstream from dams are challenging policy and scientific questions
for fluvial geomorphology. Reaches downstream from the dams have experienced
departures from natural conditions by changes in their hydrology (water yield,
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The Scientific Nature of Geomorphology: Proceedings of the 27th Binghamton Symposium in Geomorphology held 27-29
 1996 John Wiley & Sons Ltd.
September 1996. Edited by Bruce L. Rhoads and Colin E. Thorn.