Drumheller Channels National Natural Landmark
|
Drumheller channels
|
||
 |
||
| location | Adams County / Grant County , Washington , USA | |
| Geographical location | 46 ° 59 ' N , 119 ° 12' W | |
|
||
| Setup date | 1986 | |
The Drumheller Channels National Natural Landmark forms the shop window to the Drumheller Channels , the most striking example on the Columbia Plateau of the basalt tower-and-basin landscape of the Channeled Scablands . This National Natural Landmark is an extremely eroded landscape in the south of the central part of the US state Washington , characterized by hundreds of isolated, steep hills (so-called harders ), which are surrounded by an intertwined network of numerous canals, all but one of which have fallen dry. It is the classic example of the massive erosive forces of the mighty Missoula floods that reshaped the volcanic landscape of the Columbia Plateau in the late Pleistocene .
geography
The US National Park Service recognized the importance and natural beauty of the Drumheller Channels in 1986 and designated them as a National Natural Landmark. The geologist who was the first to recognize and document the evidence for the Ice Age floods, J Harlen Bretz , wrote:
"Drumheller is the most spectacular tract of butte-and basin scabland on the plateau. It is an almost unbelievable labyrinth of anastamosing channels, rock basins, and small abandoned cataracts. "
“Drumheller is the most spectacular stretch of the tower-and-basin wasteland on the plateau. It is an almost unbelievable labyrinth of anastomosing canals, rock pools and dry cataracts. "
The Drumheller Channels connect the Quincy Basin in the north with the Othello Basin in the south. The quickest way to get there is from Othello , traveling approximately 8 mi (13 km) northwest on McManamon Road, then north on Morgan Lake Road which passes through the Drumheller Channels region. The Morgan Lake Road (actually a gravel road), which runs from north to south, crosses the center of the channels, following Crab Creek . There are designated hiking trails, including a nature trail that leads from the wetlands on Crab Creek to the lookout point of one of the hardships and gives hikers an impression of this unique landscape. The Drumheller Channels can also be viewed from paved State Route 262 , which runs north on the crown of the Potholes Reservoir Dam (which has flooded part of the Scablands) and west from the heights of the Frenchman Hills .
Course of the prehistoric Columbia River
The Okanogan lobe of the Cordillera Ice Sheet moved along the valley of the Okanogan River, blocking the prehistoric course of the Columbia River, holding back water and creating Lake Spokane . Initially, the water from Lake Spokane flowed over the upper area of the Grand Coulee and the Foster Coulee to reach the Columbia River again. As the glacial masses advanced south, the Foster Coulee was cut off and the Columbia was supplied with water via the Moses Coulee , which runs south and slightly east of the prehistoric and present-day course of the Columbia. As the Okanogan rag grew, it also blocked the Moses Coulee; the Columbia found the next deeper bed in the region, which was created by erosion and forms today's Grand Coulee. After the glacial Columbia through today's region of Grand Coulee and Dry Falls flowed, he reached the Quincy Basin and the Crab Creek, the course followed southward beyond the Frenchman Hills and then turned west to run along the north side of the Saddle Mountains continue to flow and to follow the previous (and today's) course exactly above the main breakthrough, the Sentinel Gap .
Development of the Drumheller Channels
The Missoula floods poured into Lake Spokane after they had passed the Grand Coulee and greatly expanded it, then over the Dry Falls and finally came to a standstill in the Quincy Basin , which they filled; the water masses covered about 1500 km² and created the Ephrata Fan (a camp of more or less large rocks, stones and rubble at the entrance to the basin). The discharge volume was so great that the water flooded Lake Spokane in many places and the Quincy Basin also entered via the Telford-Crab Creek Scablands and the Lind Coulee (both located on the east side of the basin). On reaching the Frenchman Hills, the water level was so high that - although most of the water flowed over the valley of Crab Creek - some of the water overcame the lower elevations of the west at three points, the Evergreen and the Babcock Ridge, and thus the canal of the Columbia on the Frenchman Coulee in the southwest, the Potholes Coulee in the north center and the Crater Coulee in the northwest. Most of the floods took the route of least resistance straight south through the Drumheller Channels and expanded the valley of Crab Creek.
The height of the floods flowing through the Drumheller Channels was more than 50 meters, and that over a distance of 20 kilometers with local height differences of 2… 12 meters per kilometer of flow. In connection with water depths between 60 and 120 meters, this hydraulic potential generated the energy to generate flow speeds of up to 30 meters per second (108 km / h), which eroded the topsoil and the basalt below and thus the complex network of channels and basins , Kolke und Härtlinge, which still exists today. Some of these objects, such as the large pools, bear witness to the tremendous forces of the floods.
The Drumheller channels have their very specific character; unlike most of the other Channeled Scablands zones, there is no single central canal or major cataract. The floods passed the Drumheller Channels in a 13… 20 km wide cascade. Bretz recorded 150 individual canals and more than 180 rock pools in the region. Many of the low-lying areas such as Upper Goose Lake that are not connected to the Potholes Reservoir to the north are filled by seepage water that seeps through the basalt bedrock.
Influences of early settlement
The influence of the settlement was considerable; by the 1860s, overgrazing depleted the populations of most native grasses. Explorations of the government in the 1880s identified a large part of the region as wasteland ( English Badlands ).
Activities of the Bureau of Reclamation
The United States Bureau of Reclamation initiated the construction of the Grand Coulee Dam on the Columbia River in 1934 , about 100 mi (161 km) north of the Drumheller Channels. This dam was only part of the Columbia Basin Project , which included four major reservoirs, hundreds of pumping stations and 2,300 mi (3,700 km) of irrigation canals in the area. Irrigation began in 1951 and raised the water table. By 1980, when the final phase of the project was completed, the area of wetlands in the Columbia Basin was at least twenty times larger than before, when only seepage water and an elevated groundwater level were available. Migrating waterfowl were attracted by the water and the increased food supply in the region from the neighboring agricultural areas.
Columbia National Wildlife Refuge
The Columbia National Wildlife Refuge is part of the Drumheller Channels. Neighboring areas were integrated into the Seep Lakes Wildlife Area . More than 200 species of mammals and birds can be seen in the cliffs, marshes, grasslands, lakes, wetlands and riparian forests.
Individual evidence
- ↑ David Alt: Glacial Lake Missoula & its Humongous Floods . Mountain Press Publishing Company, 2001, ISBN 0-87842-415-6 .
- ↑ Bruce Bjornstad: On the Trail of the Ice Age Floods: A Geological Guide to the Mid-Columbia Basin . Keokee Books, San Point, Idaho 2006, ISBN 978-1-879628-27-4 .
- ^ A b J Harlen Bretz: The Channeled Scabland of the Columbia Plateau . In: Journal of Geology . 31, 1923, pp. 617-649.
- ↑ a b c d e Ted and Marge Mueller: Fire, Faults & Floods . University of Idaho Press, Moscow, Idaho 1997, ISBN 0-89301-206-8 .
- ↑ a b c V.R. Baker: Paleohydrology and Sedimentology of Lake Missoula Flooding in Eastern Washington . In: Geological Society of America (Ed.): Special Paper . 1973, p. 144.
- ^ A b Columbia National Wildlife Refuge . In: Online Encyclopedia of Washington State History . HistoryLink . Retrieved March 7, 2019.
- ^ Columbia National Wildlife Refuge . United States Fish and Wildlife Service . Retrieved March 7, 2019.
Web links
- Summary of the National Natural Landmark on the National Park Service website
- Items from the National Park Service on the glacial floods (English)
- Ice-Age Floods Institute (IAFI) website The IAFI is a non-profit organization providing environmental education about geological events in the Pacific Northwest . (English)
- Columbia National Wildlife Refuge (English)