Umtanum Ridge Water Gap

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Umtanum Ridge Water Gap

IUCN Category III - Natural Monument or Feature

View north from Umtanum Ridge into Yakima Canyon west of the Yakima River

View north from Umtanum Ridge into Yakima Canyon west of the Yakima River

location Kittitas County / Yakima County , Washington , USA
Geographical location 46 ° 51 ′  N , 120 ° 33 ′  W Coordinates: 46 ° 51 ′ 0 ″  N , 120 ° 32 ′ 40 ″  W
Umtanum Ridge Water Gap (Washington)
Umtanum Ridge Water Gap
Setup date 1980
The Yakima River as it exits the Yakima River Canyon
Fly fishing from a fishing boat on the Yakima River in the Yakima River Canyon

The Umtanum Ridge Water Gap ( English gap = gap, gap) is a geological feature in the central part of the State of Washington . It was designated a National Natural Landmark in 1980 .

The Umtanum Ridge Water Gap is a breakthrough valley of the Yakima River through the Manastash Ridge and the Umtanum Ridge , two anticline ridges of the Yakima Fold Belt near the western edge of the Columbia River Plateau . The National Natural Landmark is characterized by a series of steep mountain ridges in the Columbia River Basalt Group , which are cut in the middle by the Yakima River. It is also called the Yakima River Canyon and is located between the cities of Ellensburg and Yakima . The Washington State Route 821 , originally the main link between Ellensburg and Yakima, in parallel to the river through the canyon.

geology

The large basalt streams of the Columbia Basin and Ellensburg Formation, in some places up to more than 17,000 ft (about 5,200 m) thick, have been folded into mountain ridges (anticlines) and valleys ( synclines ) that are roughly east-west -Direction because they are the result of a north or south-facing compression. On the way to its confluence with the Columbia River , the Yakima River cuts from the Kittitas Valley southwards to the Yakima Valley through the four main ridges that arose from this compression: the Manastash Ridge, the Umtanum Ridge, the Yakima Ridge and the Ahtanum Ridge.

Looking south from Umtanum Ridge into Yakima Canyon

The highest ridge that the Yakima breaks, the Umtanum Ridge, rises up to 983 meters within one kilometer of the river, which is at its closest point at about 470 meters. This unusual behavior (creating a breakthrough valley instead of flowing around the ridge) is an example of geological precedent . It is believed that the prehistoric yakima already existed and flowed southwards through the relatively flat basalt layers. When the layers were compressed, the anticlines rose slowly. The river continued to follow its historical course, digging its way through the rising basalts so that it remained at one level. This view is supported by the meanders of today's Yakima; the meandering river slowly digs into the rising rock.

Coordinates

f1Georeferencing Map with all coordinates of the section Coordinates : OSM

Mountain ridge Coordinates
Manastash Ridge 46 ° 51 ′  N , 120 ° 23 ′  W.
Umtanum Ridge at the point of splitting into a northern and a southern ridge 46 ° 51 ′  N , 120 ° 33 ′  W.
Umtanum Water Gap in Yakima Canyon 46 ° 49 ′  N , 120 ° 27 ′  W.

Individual evidence

View from the north near Ellensburg to the Yakima Canyon.
  1. ↑ Umtanum Ridge Water Gap . In: nps.gov . National Park Service .
  2. ^ A b c Scott Babcock, Bob Carson: Hiking Washington's Geology . The Mountaineers Books, 2000, ISBN 0-89886-548-4 .
  3. ↑ a b c d Benchmark: Washington Road and Recreation Atlas . Benchmark Maps, Medford, Oregon 2002, ISBN 0-929591-53-4 .

swell

  • John Eliot Allen, Marjorie Burns, Sam C. Sargent: Cataclysms on the Columbia: a layman's guide to the features produced by the catastrophic Bretz floods in the Pacific Northwest . Timber Press, Portland, OR 1986, ISBN 0-88192-067-3 , p. 104.
  • David Alt, Donald Hyndman: Roadside Geology of Washington . Mountain Press Publishing Company, 1984, ISBN 0-87842-160-2 .
  • 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 0-89886-548-4 .
  • J Harlen Bretz: The Channeled Scabland of the Columbia Plateau . In: Journal of Geology . 31, 1923, pp. 617-649.
  • Charles L. Mason: The Geological History of the Wenatchee Valley and Adjacent Vicinity . World Publishing Company, Wenatchee, Washington 2006, ISBN 0-9719820-1-5 .
  • Ted & Marge Mueller: Fire, Faults & Floods . University of Idaho Press, Moscow, Idaho 1997, ISBN 0-89301-206-8 .
  • Channeled Scabland of Eastern Washington: The Geologic Story of the Spokane Flood . US Government Printing Office, Washington DC 1982.