Outlines the role of science in restoring or otherwise altering unwanted downstream effects of dams, including eroding river banks, changes in waterfowl habitat, threats to safe recreational use, and the loss of river sand bars, examining seven selected areas of the country -- the upper Salt River in central Arizona; the Snake River in Idaho, Oregon and Washington; the Rio Grande in New Mexico and Texas; the Chattahoochee River in Georgia; the Platte River in Wyoming, Colorado and Nebraska; the Green River in Utah; and the Colorado River in Arizona -- to focus on specific downstream effects of dams and the management issues related to their operation.
Photographs made in Grand Canyon a century ago may provide us today with a sense of history; photographs made a century later from the same vantage points give us a more precise picture of change in this seemingly timeless place. Between 1889 and 1890, Robert Brewster Stanton made photographs every 1-2 miles through the river corridor for the purpose of planning a water-level railroad route and produced the largest collection of photographs of the Colorado River at one point in time. Robert Webb, a USGS hydrologist conducting research on debris flows in the Canyon, obtained the photographs and from 1989 to 1995 replicated all 445 of the views captured by Stanton, matching as closely as possible the original camera positions and lighting conditions. Grand Canyon, a Century of Change assembles the most dramatic of these paired photographs to demonstrate both the persistence of nature and the presence of humanity. Unexpected longevity of some plant species, effects of animal grazing, and expansion of cacti are all captured by the replicate photographs. More telling is evidence of the impact of Glen Canyon Dam: increased riparian vegetation, new marshes, aggraded debris fans, and eroded sand bars. In the accompanying text, Webb provides a thorough analysis of what each pair of photographs shows and places the project in its historical context. Complementing his narrative are six sidebar articles by authorities on Canyon natural history that further attest to a century of change. The level of detail obtained from the photographs represents one of the most extensive long-term monitoring efforts ever conducted in a national park; it is the most detailed documentation effort ever performed using repeat photography. Much more than simply a picture book, Grand Canyon, a Century of Change is an environmental history of the river corridor, a fascinating book that clearly shows the impact of human influence on Grand Canyon and warns us that its future is very much in our hands.
Allow yourself to be taken back into deep geologic time when strange creatures roamed the Earth and Western North America looked completely unlike the modern landscape. Volcanic islands stretched from Mexico to Alaska, most of the Pacific Rim didn’t exist yet, at least not as widespread dry land; terranes drifted from across the Pacific to dock on Western Americas’ shores creating mountains and more volcanic activity. Landscapes were transposed north or south by thousands of kilometers along huge fault systems. Follow these events through paleogeographic maps that look like satellite views of ancient Earth. Accompanying text takes the reader into the science behind these maps and the geologic history that they portray. The maps and text unfold the complex geologic history of the region as never seen before. Winner of the 2021 John D. Haun Landmark Publication Award, AAPG-Rocky Mountain Section