Conclusions
Ecological prosperity =
economic prosperity
 Appleton Dam before
removal |
 Appleton Dam during
removal |
 Appleton Dam after
removal |
We may find that managing a river-for floods,
navigation or power-costs more than we imagine or
estimate. Maintaining those alterations when a
river's processes are trying to restore a natural
order is also costly. Natural streams often prove
to be the low-cost alternatives.
For example, many of the small mill and
hydropower dams built a century ago are now
decrepit and dangerous. By altering the natural
hydrodynamic forces of the stream, the reservoirs
have filled with silt. In many cases, dam owners,
such as cities and power companies, find it is
cheaper to remove the dam and restore the channel
than it is to rebuild the structure. Often, what is
lost in power production, for example, is more than
compensated by increased value to human safety,
fish and wildlife populations, and recreation.
In Minnesota in recent years, dams have been
removed on many streams, including the Cannon,
Kettle, Crow, and Otter Tail (see story of Frazee Dam).
According to the conservation group American
Rivers, 480 U.S. dams have been removed, most
within the last 20 years, many for cost
considerations in addition to environmental
benefit.
