Editing Lake Champlain (section)

==Geology==
{{See|Champlain Sea}}
[[File:Lake Champlain by Sentinel-2.jpg|alt=|thumb|Sentinel-2 satellite photo]]
The Champlain Valley is the northernmost unit of a landform system known as the [[Great Appalachian Valley]], which stretches between [[Quebec]], Canada, to the north, and [[Alabama]], U.S., to the south. The Champlain Valley is a [[Physiographic regions of the world|physiographic section]] of the larger [[Saint Lawrence River|Saint Lawrence Valley]], which in turn is part of the larger [[Appalachian Mountains|Appalachian]] physiographic division.<ref name="USGS-Water">{{cite web |title=Physiographic divisions of the conterminous U. S. |website=U.S. Geological Survey |url=http://water.usgs.gov/GIS/metadata/usgswrd/XML/physio.xml |access-date=December 6, 2007 |archive-date=December 5, 2007 |archive-url=https://web.archive.org/web/20071205095639/http://water.usgs.gov/GIS/metadata/usgswrd/XML/physio.xml |url-status=live }}</ref>

Lake Champlain is one of numerous large lakes scattered in an arc through [[Labrador]], in Canada, the northern United States, and the [[Northwest Territories]] of Canada.<ref>{{cite web|url=https://www.britannica.com/place/Lake-Champlain|date=|title=LAKE CHAMPLAIN|website=britannica.com|publisher=Britannica|author=Amy Tikkanen|access-date=2024-08-22}}</ref><!-- does this arc have a name or cause?-->

It is the thirteenth-largest lake by area in the U.S. Approximately {{convert|1269|km2|order=flip}} in area, the lake is {{convert|172|km|order=flip}} long and {{cvt|23|km|order=flip}} across at its widest point,<ref name=brit/> and has a maximum depth of approximately {{convert|400|ft|fathom m|lk=out}}. The lake varies seasonally from about {{cvt|95|to|100|ft}} above [[Sea level|mean sea level]].<ref>{{cite web |title=Lake Champlain Lake Level – King St. Ferry Dock (1977–2006) |website=NOAA.gov |url=http://www.erh.noaa.gov/btv/climo/Lake_Champlain_BoxWhisker.png |date=May 3, 2012 |access-date=May 3, 2012 |archive-date=September 24, 2015 |archive-url=https://web.archive.org/web/20150924001855/http://www.erh.noaa.gov/btv/climo/Lake_Champlain_BoxWhisker.png |url-status=live }}</ref><ref>{{Cite web |title=Lake Champlain |url=https://atlas.lcbp.org/nature-environment/lake-champlain/ |access-date=2024-06-28 |website=Lake Champlain Basin Atlas |language=en-US}}</ref>

===Hydrology===
[[File:Lake Champlain.jpg|thumb|left|Lake Champlain in Burlington Harbor during sunset on May 27, 2012]]

Lake Champlain is in the [[Lake Champlain Valley]] between the [[Green Mountains]] of [[Vermont]] and the [[Adirondack Mountains]] of [[New York (state)|New York]], drained northward by the {{convert|106|mi|km|adj=mid|-long}} [[Richelieu River]] into the [[St. Lawrence River]] at [[Sorel-Tracy, Quebec]], northeast and downstream of [[Montreal]]. The Champlain basin collects waters from the northwestern slopes of the Green Mountains and the eastern portion of the Adirondack Mountains, reaching as far south as the {{convert|32|mi|km|adj=mid|-long}} [[Lake George (lake), New York|Lake George]] in New York.

Lake Champlain drains nearly half of Vermont, and approximately 250,000 people get their drinking water from the lake.<ref name="bfp100811">{{Cite news |first=John |last=Curran |title=State seeks dismissal of phosphorus lawsuit |url=http://www.burlingtonfreepress.com/article/20100811/NEWS02/8110319/Vermont-urges-dismissal-of-suit-over-lake-phosphorus |newspaper=[[Burlington Free Press]] |location=Burlington, Vermont |page=1B |date=August 11, 2010}}{{dead link|date=May 2017|bot=InternetArchiveBot|fix-attempted=yes }}</ref>

The lake is fed in Vermont by the LaPlatte, [[Lamoille River|Lamoille]], [[Missisquoi River|Missisquoi]], [[Poultney River|Poultney]] and [[Winooski River|Winooski]] rivers, along with Lewis Creek, Little Otter Creek and [[Otter Creek (Vermont)|Otter Creek]].<ref>{{cite web |url=http://sol.lcbp.org/images/Figures%20for%20Presentations/Fig5_P_Medalie2015_symb-tribs.png |title=2015 State of the Lake: Figure 5 |date=2015 |website=Lake Champlain Basin Program |access-date=August 28, 2016 |archive-url=https://web.archive.org/web/20160910215537/http://sol.lcbp.org/images/Figures%20for%20Presentations/Fig5_P_Medalie2015_symb-tribs.png |archive-date=2016-09-10 |url-status=dead}}</ref> In New York, it is fed by the [[Ausable River (New York)|Ausable]], [[Boquet River|Boquet]], [[Chazy River|Great Chazy]], [[La Chute River|La Chute]], Little Ausable, [[Chazy River|Little Chazy]], Salmon and [[Saranac River|Saranac]] rivers, along with Putnam Creek. In Quebec, it is fed by the [[Pike River, Quebec|Pike River]].

It is connected to the [[Hudson River]] by the [[Champlain Canal]].

Parts of the lake freeze each winter, and in some winters the entire lake surface freezes, referred to as "closing".<ref>{{cite news |first=Matt |last=Sutkoski |title=Lack of ice cover might be affecting the ecology of Lake Champlain |url=http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/vermont/sutkoskibfp.pdf |newspaper=Burlington Free Press |date=January 22, 2012 |access-date=October 2, 2016 |archive-url=https://web.archive.org/web/20161003111356/http://www.nature.org/ourinitiatives/regions/northamerica/unitedstates/vermont/sutkoskibfp.pdf |archive-date=2016-10-03 |url-status=dead}}</ref> In July and August, the lake temperature reaches an average of {{cvt|70|°F|0}}.<ref>{{cite web |location=Lake Champlain at Burlington, VT |url=http://waterdata.usgs.gov/vt/nwis/uv?cb_00011=on&cb_00095=on&cb_62614=on&format=gif_default&site_no=04294500&period=&begin_date=2016-07-01&end_date=2016-10-02 |title=National Water Information System |website=U.S. Geological Survey (USGS 04294500) |access-date=October 2, 2016 |archive-date=September 22, 2020 |archive-url=https://web.archive.org/web/20200922154043/https://waterdata.usgs.gov/vt/nwis/uv?cb_00011=on&cb_00095=on&cb_62614=on&format=gif_default&site_no=04294500&period=&begin_date=2016-07-01&end_date=2016-10-02 |url-status=live }}</ref><ref>{{cite web |url=http://waterdata.usgs.gov/nwis/monthly?referred_module=sw&amp;site_no=04294500&amp;por_04294500_65128=1270506,00011,65128,2014-10,2015-10&amp;format=html_table&amp;date_format=YYYY-MM-DD&amp;rdb_compression=file&amp;submitted_form=parameter_selection_list |website=U.S. Geological Survey (USGS 04294500) |location=Lake Champlain at Burlington, VT |title=National Water Information System: Surface-Water Monthly Statistics for the Nation |access-date=October 2, 2016 |archive-date=November 17, 2017 |archive-url=https://web.archive.org/web/20171117020920/https://waterdata.usgs.gov/nwis/monthly?referred_module=sw&site_no=04294500&por_04294500_65128=1270506,00011,65128,2014-10,2015-10&format=html_table&date_format=YYYY-MM-DD&rdb_compression=file&submitted_form=parameter_selection_list |url-status=live }}</ref>

===Chazy Reef===
The [[Chazy Formation|Chazy Reef]] is an extensive [[Ordovician]] [[carbonate rock]] [[Formation (geology)|formation]] that extends from [[Tennessee]] to Quebec and [[Newfoundland and Labrador|Newfoundland]]. The oldest reefs are around "The Head" of the south end of [[Isle La Motte]]; slightly younger reefs are found at the Fisk Quarry, and the youngest (the famous coral reefs) are in fields to the north.<ref>{{cite web |website=[[University of Vermont]] |author=Mehrtens, Charlotte, Professor of Geology |title=Chazy Reef |url=https://dec.vermont.gov/geological-survey/vermont-geology/Chazy |access-date=January 20, 2020 |archive-date=June 4, 2021 |archive-url=https://web.archive.org/web/20210604153831/https://dec.vermont.gov/geological-survey/vermont-geology/Chazy |url-status=live }}</ref>