Regulated Rivers - Hydro-Environmental Analysis: Freshwater Environments - page 78

3.7.1 p reSerVatIon
The preservation of existing free-lowing rivers is an alternative. A few of our free-lowing rivers
have been protected and preserved as wild and scenic rivers under the National Wild and Scenic
Rivers System:
It is hereby declared to be the policy of the United States that certain selected rivers of the Nation
which, with their immediate environments, possess outstandingly remarkable scenic, recreational,
geologic, ish and wildlife, historic, cultural or other similar values, shall be preserved in free-lowing
condition, and that they and their immediate environments shall be protected for the beneit and enjoy-
ment of present and future generations. The Congress declares that the established national policy
of dams and other construction at appropriate sections of the rivers of the United States needs to be
complemented by a policy that would preserve other selected rivers or sections thereof in their free-
lowing condition to protect the water quality of such rivers and to fulill other vital national conserva-
tion purposes. (Wild & Scenic Rivers Act, October 2, 1968)
According to the U.S. Fish and Wildlife Service, Wild and Scenic Rivers program, as of 2008, the
national system protects more than 11,000 miles of 166 rivers in 38 states and the Commonwealth of
Puerto Rico. However, that is little more than one-quarter of 1% of the nation's rivers.
3.7.2 n aturaLIzatIon or r eHabILItatIon
A management alternative for regulated or disturbed rivers may be to restore or rehabilitate them.
While the terms are often used interchangeably, the goals of restoration or rehabilitation are often
quite different. The goal of restoration is usually to reestablish the general structure and func-
tion of the river to that existing prior to the disturbance, the preexisting condition. Restoration
typically requires a detailed understanding of the structure and function of not only the river but
also its watershed prior to the disturbance. A problem is that regulation is so pervasive that many
of the characteristics of natural rivers, such as the natural low hydrograph, are poorly known or
understood, thus making restoration problematic. An alternative strategy may be rehabilitation. To
rehabilitate is to restore to useful purpose, or to make habitable again. Restoration and rehabilitation
strategies are the subject of Chapter 8.
3.7.3 M anaGeMent
As indicated at the beginning of this topic, a common theme is often “one generation's solution is
the next generation's problem.” River regulation is a common solution that has existed for many gen-
erations and by far the majority of our rivers and streams are regulated to some degree. The regula-
tion of rivers has provided a variety of beneits, including lood control, navigation, hydroelectric
power, water supply, and other uses. However, the impact of regulated rivers is an ecological system
that is often far removed in its characteristics from naturally occurring rivers. These systems are
already altered from their natural condition, so preservation is not an option, nor is naturalization or
restoration for the majority of regulated rivers. The only alternative is management since “like it or
not we control the destiny of these streams” (Collier et al. 2000).
As indicated in “Dams and rivers: A primer on downstream effects of dams” (Collier et al. 2000),
river managers have traditionally concentrated on eficiency, sometimes to the neglect of instream
environmental requirements. For the majority of regulated rivers, engineering goals will continue
to dictate the river engineering design and management procedures. However, these river systems,
although regulated, do have an intrinsic environmental value. That environmental value can be
enhanced if we choose to enhance and manage for those values.
River engineering design and management are often based on some optimization of the complex
and diverging interests of water users, such as for navigation, hydropower, and water supply. Often,