Human Impacts on Geyser Basins
Alethea Steingisser and W. Andrew Marcus
eysers and hot springs are relatively rare geologic features that are vulnerable to impacts from human activities. Geysers in particular are susceptible to human impacts, with many of the world’s geysers having already been altered or completely extinguished by geothermal energy development and tourism. Yellowstone National Park was set aside as the world’s first national park due primarily to its multiple geyser basins, an act that set the stage for protect- ing lands deemed unique in the world. The park has lost a relatively small number of geysers to tourism-related activities, but there is potential for greater damage if geothermal develop- ment occurs outside the park. G
This article places the remarkable geyser activity of Yel- lowstone within a global context, examines human impacts to geyser basins worldwide, and examines historical and poten- tial future impacts to thermal features in Yellowstone resulting from tourism and possible geothermal development outside the park. This article is based on a master’s thesis in geography completed at the University of Oregon in 2006.
There are few global, systematic accounts of human impacts to geysers and other geothermal features; most research is site specific. T. Scott Bryan provided a synthesis of global geyser basin distribution and human impacts as an appendix in his guidebooks, The Geysers of Yellowstone (1991, 1995). Donald White, known for his research on geothermal resources and geyser basins in particular, also documented global impacts of
geothermal development on geyser basins (1967, 1968, 1979, 1988, 1992). This article expands on the contributions made by Bryan, White, and others to provide a historical summary of geyser basins as a global resource that has been altered by various types of human activities.
In addition to a literature review, research in this article comes from many wonderful hours absorbed in the archives at the Yellowstone National Park Heritage and Research Center in Gardiner, Montana, and the National Park Service (NPS) library and photo archives at Harpers Ferry, West Virginia. Additional geyser information and historical photos were found through the Geyser Observation and Study Association, a nonprofit organization dedicated to the collection and dis- semination of information about geysers.
Geysers and Their Controls
Geothermal regions occur where heat from Earth’s inte- rior rises and creates phenomena such as volcanoes, geysers, and hot springs. While volcanic features are generally spread over relatively large areas associated with plate boundaries and hot spots, hydrothermal areas (where heated water rises to the surface to create springs and geysers) are more limited in extent due to local-scale controls on subsurface heat flow, water avail- ability, and pressure. Fournier (1989) describes these controls in Yellowstone in detail.
The difference between geysers and hot springs is the presence or absence of pressure. Pressure is controlled by a variety of factors including rock type and configuration of the
17(1) • 2009