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William M. Lewis, Jr.
Effects of Human Activities on Aquatic Ecosystems of the Western United States
Because human use of water has been the key to development of much of the western U.S., one might correctly surmise that humans have interfered greatly with aquatic environments in the West. Hydrologic manipulation is perhaps the most obvious form of interference in natural systems. It has adverse consequences that either were not appreciated earlier, or to which increasing importance has gradually been attached as a result of changes in societal attitudes. Physical degradation of aquatic environments is also pervasive, difficult to control because of private property rights, and destructive of many of the potential values of aquatic environments. Water quality, which involves discharge of pollutants to water, is also a major concern but is under relatively strong regulatory control as compared with other types of degradation. A final problem, which is pressing with increasing effect on aquatic environments of the West is the introduction of invasive species. This presentation deals with the effects of these various environmental challenges to inland waters and to the legal and other responses of U.S. society to them up to this point. |
