3rd edition. Describes the Bureau of Reclamation's experience in the design and construction of dams and control works. Illustrated throughout.

On January 8, 1971, President Richard M. Nixon signed into law the bill creating the Chesapeake & Ohio Canal National Historical Park. In the mid-1970s, National Park Service historian Harlan D. Unrau produced a major, handwritten, multi-volume study of the history, engineering, operation, maintenance, and other aspects of the Chesapeake & Ohio canal. A rough, unedited typed version was produced in the early 1980s for general use by park staff. In 2006, C&O Canal NHP volunteers began the task of transcribing the Unrau work into MS Word.The work represents an early compilation of the canal's...

Estimating travel demand for alternative transportation systems (ATS) is challenging in any context, but is even more daunting for Federal Land Management Agencies (FLMAs). Federal public land sites vary widely in their characteristics. Moreover, travel by visitors to, from, and within FLMAs often has little resemblance to the more common types of transportation for which traditional demand modeling methods have been developed.

The Great Smoky Mountains are among the oldest mountains in the world and the highest in the Appalachian Mountain chain. These peaks and ridges have been both a daunting obstacle and a source of inspiration since the earliest people set foot in the area. Long before humans arrived, geologic processes, climatic shifts, weather, and fire shaped this environment, producing a dynamic ecosystem.

The geology of the Guadalupe Mountains is exceptional, so exceptional that the International Commission on Stratigraphy selected this section of rocks to serve as the standard against which all other rocks of Middle Permian age (270-260 million years ago) are compared. This distinction is a benefit to the National Park Service, supporting its mission, as well as a benefit to the international scientific community. It is also a bonus for backcountry visitors, providing an interesting hiking destination recognized for its geologic uniqueness.

Great Sand Dunes National Park and Preserve is home to the tallest sand dunes in North America with some dunes rising 750 feet (230 m) above the San Luis Valley floor. Unique to the Rocky Mountain physiographic province, the high- altitude desert dunes of the park and preserve represent one of the most complex dune systems in the world. The 30 square miles (78 sq km) of Great Sand Dunes are part of a larger dune field that includes a relatively flat sand sheet and sabkha and covers 150 square miles (389 sq km). High velocity, bi- directional winds shape the dunes, which offer the visitor an...

The Florida Keys National Wildlife Refuges Complex is comprised of four refuges situated in the Florida Keys. Crocodile Lake National Wildlife Refuge is located at the northern end of the Florida Keys near Key Largo, Florida. The Lower Florida Keys Refuges are physically separated from Crocodile Lake NWR. This group of three refuges, National Key Deer Refuge, Key West National Wildlife Refuge, and Great White Heron National Wildlife Refuge, is situated between the city of Marathon and the Marquesas Keys, which are located west of Key West, Florida. The U.S. Fish and Wildlife Service developed...

The Fish and Wildlife Service prepared this Comprehensive Conservation Plan to guide the management of Pea Island National Wildlife Refuge in Dare County, North Carolina. The plan outlines programs and corresponding resource needs for the next 15 years, as mandated by the National Wildlife Refuge System Improvement Act of 1997.