Editing Willamette River (section)

==Watershed==
[[File:Wpdms shdrlfi020l willamette valley.jpg|200px|right|thumb|Willamette Valley map showing main stem and major tributaries|alt=the Willamette valley watershed]]

The Willamette River drains a region of {{convert|11478|sqmi|km2}}, which is 12&nbsp;percent of the total area of Oregon.<ref name="Oregon Encyclopedia" /> Bounded by the Coast Range to the west and the Cascade Range to the east, the river basin is about {{convert|180|mi|km}} long and {{convert|100|mi|km}} wide.<ref name="Benke 616" /> Elevations within the watershed range from {{convert|10495|ft|m}} at [[Mount Jefferson (Oregon)|Mount Jefferson]] in the Cascade Range<ref name="Benke 616" /> to {{convert|10|ft|m}} at the mouth on the Columbia River.<ref name="gnis"/> Watersheds bordering the Willamette River basin are those of the [[Little Deschutes River (Oregon)|Little Deschutes River]] to the southeast, the [[Deschutes River (Oregon)|Deschutes River]] to the east, and the [[Sandy River (Oregon)|Sandy River]] to the northeast; the [[North Umpqua River|North Umpqua]] and [[Umpqua River|Umpqua]] rivers to the south; coastal rivers including (from south to north) the [[Siuslaw River|Siuslaw]], the [[Alsea River|Alsea]], the [[Yaquina River|Yaquina]], the [[Siletz River|Siletz]], the [[Nestucca River|Nestucca]], the [[Trask River|Trask]], and the [[Wilson River (Oregon)|Wilson]] to the west; the [[Nehalem River|Nehalem]] and the [[Clatskanie River|Clatskanie]] to the northwest, and the Columbia River to the north.<ref>Loy, ''et al.'', pp. 168–69</ref>

About 2.5&nbsp;million people lived in the Willamette River basin as of 2010, about 65&nbsp;percent of the population of Oregon.<ref name="hydrologic observatory">{{cite web |title=The Basins: About the Willamette River basin |url=http://pnwho.forestry.oregonstate.edu/site/index.php |publisher=Oregon State University |work=The Pacific Northwest Hydrologic Observatory |archive-url=https://web.archive.org/web/20141209051249/http://pnwho.forestry.oregonstate.edu/site/index.php |archive-date=December 9, 2014}}</ref> As of 2009, the basin contained 20 of the 25 most populous cities in Oregon.<ref name="DeLorme"/><ref name = "city populations">{{cite web |url=http://factfinder.census.gov/servlet/GCTTable?_bm=y&-geo_id=04000US41&-_box_head_nbr=GCT-T1-R&-ds_name=PEP_2009_EST&-_lang=en&-format=ST-9S&-_sse=on |title=Oregon&nbsp;– Place 2009 Population Estimates |publisher=U.S. Census Bureau |access-date=January 14, 2011}}{{dead link|date=June 2022|bot=medic}}{{cbignore|bot=medic}}</ref> These cities include Springfield, Eugene, Corvallis, Albany, Salem, Keizer, Newberg, Oregon City, West Linn, Milwaukie, Lake Oswego, and Portland.<ref name="DeLorme"/><ref name = "city populations"/> The largest is Portland, with more than 500,000 residents.<ref name = "city populations"/> Not all of these cities draw water in part or exclusively from the Willamette for their municipal water supply.<ref>{{cite web |url=http://www.corvallisoregon.gov/index.aspx?page=135 |title=Water Utility |publisher=City of Corvallis, Oregon |access-date=November 16, 2016}}</ref><ref>{{cite web |url=https://www.cityofalbany.net/images/stories/publicworks/water/wqr/2015-albany-wqr.pdf |page=3 |title=2015 Annual Water Quality Report |publisher=City of Albany, Oregon |access-date=November 16, 2016}}</ref> Other cities in the watershed (but not on the main-stem river) with populations of 20,000 or more are Gresham, Hillsboro, Beaverton, Tigard, McMinnville, Tualatin, [[Woodburn, Oregon|Woodburn]], and Forest Grove.<ref name="DeLorme"/><ref name = "city populations"/>

Sixty-four&nbsp;percent of the watershed is privately owned, while 36&nbsp;percent is publicly owned.<ref name = "Benke"/> The [[United States Forest Service|U.S. Forest Service]] manages 30&nbsp;percent of the watershed, the U.S. [[Bureau of Land Management]] 5&nbsp;percent, and the State of Oregon 1&nbsp;percent.<ref name = "Benke"/> Sixty-eight&nbsp;percent of the watershed is forested; agriculture, concentrated in the Willamette Valley, makes up 19&nbsp;percent, and urban areas cover 5&nbsp;percent.<ref name = "Benke"/> More than {{convert|81000|mi|km}} of roads criss-cross the watershed.<ref name = "Benke">Benke, ''et al.'', pp. 616–17</ref>

In 1987, the [[United States Secretary of the Interior|U.S. Secretary of the Interior]] designated {{convert|713|acre|ha}} of the watershed in Benton County as a [[National Natural Landmark]]. This area is the [[Willamette Floodplain]], the largest remaining unplowed native grassland in the North Pacific geologic province, which encompasses most of the Pacific Northwest coast.<ref>{{cite web |title=Willamette Floodplain |publisher=National Park Service |url=https://www.nps.gov/subjects/nnlandmarks/site.htm?Site=WIFL-OR |access-date=November 16, 2016 |archive-url=https://web.archive.org/web/20161117151813/https://www.nps.gov/subjects/nnlandmarks/site.htm?Site=WIFL-OR |archive-date=November 17, 2016 |url-status=live}}</ref>