Editing Yakima River (section)

== Course ==

The river rises in the [[Cascade Range]] at an elevation of {{convert|2449|ft|m|0}} at Keechelus Dam on [[Keechelus Lake]] near [[Snoqualmie Pass]], near [[Easton, Washington|Easton]]. The river flows through that town, skirts [[Ellensburg, Washington|Ellensburg]], passes the city of [[Yakima, Washington|Yakima]], and continues southeast to [[Richland, Washington|Richland]], where it flows into the [[Columbia River]] creating the [[Yakima River Delta]] at an elevation of {{convert|340|ft}}.

About 9 million years ago, the Yakima River flowed south from near [[Vantage, Washington|Vantage]] to the [[Tri-Cities, Washington|Tri-Cities]], and then turned west straight for the [[Pacific Ocean|ocean]] through Badger Canyon west of [[Kennewick, Washington|Kennewick]]. Badger Canyon was once a waterway of the Yakima River, this pre-existing channel led the Yakima River to make tribute to the [[Columbia River]] at the current location of the city of Kennewick. Beginning nearly 15,000 years ago the [[Columbia Plateau]] was transformed by the successive [[Missoula Floods|Missoula glacial outburst floods]]. Much of the flood water made way down the Columbia river Channel where a 'choke-point' known as [[Wallula Gap]] caused the restriction of flow. Floodwaters began ponding near the Tri-Cities resulting in the back-flooding of the Columbia's tributary valleys. Badger Canyon was an entry point for back-flooding of the Yakima Valley, successive floods left behind thick deposits of sediments in Badger Canyon and the Valley beyond. These flood deposits which were deposited in large quantities in short amounts of time changed the ground elevation within Badger Canyon causing the Yakima River to re-route north of Red Mountain and enter the Columbia River by present-day [[Richland, Washington|Richland]].{{citation needed|date=February 2020}}

During the last [[ice age]], the [[Missoula Floods]] further altered the landscape of the area, opening up the Horn Rapids area to the Yakima River. The [[Amon Creek|West Fork of Amon Creek]] now utilizes Badger Canyon.<ref name="geocache">
{{cite web
 | title= Amon Basin Earthcache
 | publisher= Groundspeak
 | url= http://www.geocaching.com/seek/cache_details.aspx?guid=6f35a75f-0c7c-46aa-bcf4-39b8a08a25e2
 | access-date= 20 Feb 2013
}}
</ref>

The first western explorers to visit the river were [[Lewis and Clark Expedition|Lewis and Clark]] on or about October 17, 1805. They stopped briefly at the confluence of the Yakima and the Columbia, although they did not proceed upriver. The river was then known to local Native Americans as "Tap Teel", although the area has been inhabited since prehistory.