Watersheds & Time Horizons
by Jean Cutler Prior
The book IOWA - Portrait of the
Land* brought into focus the natural resource issues we face today as a consequence of our history of using Iowa's
land. Two of the most prominent issues are soil loss and water quality. To deal
effectively with these matters, we need to understand how the basic processes of
land and water work across natural spans of earth and time.
People generally know only the modern landscape and just that segment of
it experienced during the months and years of their lifetime. Geologists, on
the other hand, work daily with the evolution of dozens of ancient landscapes
and with future landscapes as well. The concept of watersheds is basic to this
process, as is the interconnectedness of change, whether it occurs over short or long
periods of time. A 100 million-year-old outcrop of Cretaceous sandstone
at Springbrook State Park and the sediment load that moved down Jasper
County's Walnut Creek between last February and last July have a lot in common.
Today, Iowa Geological Survey geologists increasingly apply their understanding of events that persist through geologic time to the problems of land and water that Iowans face on a human time-scale. The studies described in this issue of Iowa Geology all illuminate some aspect of watersheds and time-horizons as they apply to water quality and soil loss in Iowa. This scientific activity can help to inform and clarify the public debate on these issues as well as lead to better natural resource and environmental decision-making.
Springbrook State Park. Photo by Roger Hill
*This 92-page full-color book was released by the Iowa Department of Natural Resources on Earth Day, April 22, 2000. It tells the story of the state's natural resources, including their history, current status and trends, and a challenge for the future, all in readable prose and with numerous photos, illustrations, and maps. Copies are available for $5 by calling (515) 281-5918 in Des Moines or (319)335-1575 in Iowa City.