National Recreational Area
Interpreting the Landscape
Violent events thousands and millions of years ago created the landscape of Coulee Dam and most of eastern Washington. The dark layered rock walls you see as you travel along the lake were built from lava that gushed out of enormous cracks in the earth. Lakeshore sand and gravel terraces are evidence of a more recent event – the Ice Age. Prevailing geologic theory suggests that during glaciation, spectacular catastrophic floods raged through this area, carving the canyon of the Grand Coulee and other deep channels.
A Gift of Change
In a region renowned for towering trees, soaring mountains, deep gorges, and expansive wilderness, Coulee Dam National Recreation Area can rightfully claim a place among the Pacific Northwest's outstanding resources. Its dominant feature, Lake Roosevelt, is the area's largest lake. On its waters you will find conditions ideal for motorboating, waterskiing, sailing, and fishing. And along shore, the lake paints a backdrop to surrounding sagebrush hills and forested mountains where you can camp, picnic, hike, hunt, and sightsee.
The creation of this sprawling recreation area began with 24 million tons of concrete and steel: Grand Coulee Dam. A Goliath of a dam, it was built to turn the power of the Columbia River into electricity and to store water sufficient to turn vast deserts into productive farmlands. In 1946, five years after the dam was completed, the reservoir called Lake Roosevelt and its shores were designated Coulee Dam National Recreation Area.
The National Park Service manages the recreational aspects of this man-made resource and acts as caretaker of the area's past, preserving reminders of the days when native Americans fished the free-flowing Columbia River and fur trappers, farmers, missionaries, and soldiers first worked and settled this region. Here in Coulee Dam, the new and the old coexist side by side.
Information on the area's history, wildlife, geology, and what to see and do is available at visitor centers at Fort Spokane and Kettle Falls, and at park headquarters in the town of Coulee Dam. The visitor centers are open daily May through October. The rest of the year they are open intermittently. Headquarters is open weekdays year-round. Schedules of special events, including evening programs, hikes, and water activities, are posted.
Coulee Dam National Recreation Area stretches 130 miles along the length of Lake Roosevelt and embraces the lower reaches of many rivers and streams, including the Spokane and Kettle Rivers. Most of the water comes from glacial ice, lakes, and snow high in the Canadian Rockies. Currents run slowly in the lake, swifter in the rivers and streams. Lake water temperatures rise slowly from June, when they range from 60° F, to August, when temperatures reach 70°s F. Temperatures vary only slightly from north to south, but the Spokane River arm tends to be 5°-8° F warmer than the rest of the lake. Lake level also varies according to season. The lake is highest from late June through most of the winter. In late winter and early spring the water level is lowered as much as 100 feet to accommodate spring runoff.
The General park map handed out at the visitor center is available on the park's map webpage.For information about topographic maps, geologic maps, and geologic data sets, please see the geologic maps page.
A geology photo album has not been prepared for this park.For information on other photo collections featuring National Park geology, please see the Image Sources page.
Currently, we do not have a listing for a park-specific geoscience book. The park's geology may be described in regional or state geology texts.
Parks and Plates: The Geology of Our National Parks, Monuments & Seashores.
Lillie, Robert J., 2005.
W.W. Norton and Company.
9" x 10.75", paperback, 550 pages, full color throughout
The spectacular geology in our national parks provides the answers to many questions about the Earth. The answers can be appreciated through plate tectonics, an exciting way to understand the ongoing natural processes that sculpt our landscape. Parks and Plates is a visual and scientific voyage of discovery!
Ordering from your National Park Cooperative Associations' bookstores helps to support programs in the parks. Please visit the bookstore locator for park books and much more.
For information about permits that are required for conducting geologic research activities in National Parks, see the Permits Information page.
The NPS maintains a searchable data base of research needs that have been identified by parks.
A bibliography of geologic references is being prepared for each park through the Geologic Resources Evaluation Program (GRE). Please see the GRE website for more information and contacts.
NPS Geology and Soils PartnersAssociation of American State Geologists
Geological Society of America
Natural Resource Conservation Service - Soils
U.S. Geological Survey
Currently, we do not have a listing for any park-specific geology education programs or activities.
General information about the park's education and intrepretive programs is available on the park's education webpage.For resources and information on teaching geology using National Park examples, see the Students & Teachers pages.