Editing Great Salt Lake (section)

==Hydrology==
[[Image:Great Salt Lake Map.jpg|thumb|250px|left|Map of Great Salt Lake]]
Because of its high [[salt]] concentration, the lake water is unusually [[density|dense]], and most people can float more easily than in other bodies of water, particularly in Gunnison Bay, the saltier north arm of the lake.<ref name = "Utah GS-Salt"/>

Water levels have been recorded since 1875,<ref name="USGS-GSL"/> averaging about {{convert|4,200|ft|m}} above [[sea level]]. Since the Great Salt Lake is a shallow lake with gently sloping shores around all edges except on the south side, small variations in the water level greatly affect the extent of the shoreline. The water level can rise dramatically in wet years and fall during dry years. The water level is also affected by the amount of water flow diverted for agricultural and urban uses. The Jordan and Weber rivers, in particular, are diverted for other uses.<ref name="Morgan p. 22"/> In the 1880s, [[Grove Karl Gilbert]] predicted that the lake&nbsp;– then in the middle of many years of recession&nbsp;– would virtually disappear except for a small remnant between the islands.<ref>{{harvp|Morgan|1947|p=23}}.</ref>

A 2014 study used tree rings collected in the watershed of the Great Salt Lake to create [[:commons:File:Screen Shot 2015-11-12 at 4.08.36 AM.png|a 576-year record of lake level]] reconstruction.<ref name=derose>{{cite journal |first1 = R. Justin |last1 = DeRose |first2 = Shih-Yu |last2 = Wang |first3 = Brendan M. |last3 = Buckley |first4 = Matthew F. |last4 = Bekker |name-list-style = amp |year = 2014 |title = Tree-ring reconstruction of the level of Great Salt Lake, USA |journal = The Holocene |volume = 24 |issue = 7 |pages = 805–813 |doi = 10.1177/0959683614530441 |bibcode = 2014Holoc..24..805D |s2cid = 10729111 }}</ref> The lake level change is strongly modulated by Pacific Ocean-coupled ocean/atmospheric oscillations at low frequency and therefore reflects the decadal-scale wet/dry cycles that characterize the region.<ref>{{cite journal |doi = 10.1175/2011JCLI4225.1 |volume = 25 |title = Multidecadal Drought Cycles in the Great Basin Recorded by the Great Salt Lake: Modulation from a Transition-Phase Teleconnection |journal = Journal of Climate |year = 2012 |pages = 1711–1721 |last1 = Wang |first1 = Shih-Yu |last2 = Gillies |first2 = Robert R. |last3 = Reichler |first3 = Thomas |issue = 5 |bibcode = 2012JCli...25.1711W |url = https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1003&context=psc_facpub |doi-access = free }}</ref><ref>{{cite journal |doi = 10.1175/2009JCLI2979.1 |volume = 23 |title = Coherence between the Great Salt Lake Level and the Pacific Quasi-Decadal Oscillation |journal = Journal of Climate |year = 2010 |pages = 2161–2177 |last1 = Wang |first1 = Shih-Yu |last2 = Gillies |first2 = Robert R. |last3 = Jin |first3 = Jiming |last4 = Hipps |first4 = Lawrence E. |issue = 8 |bibcode = 2010JCli...23.2161W |url = https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1016&context=psc_facpub |doi-access = free }}</ref> By capturing these climate oscillations<ref>{{cite journal |doi = 10.1175/2010JHM1352.1 |volume = 12 |title = Incorporation of Pacific SSTs in a Time Series Model toward a Longer-Term Forecast for the Great Salt Lake Elevation |journal = Journal of Hydrometeorology |year = 2011 |pages = 474–480 |last1 = Gillies |first1 = Robert R. |last2 = Chung |first2 = Oi-Yu |last3 = Wang |first3 = Shih-Yu |last4 = Kokoszka |first4 = Piotr |issue = 3 |bibcode = 2011JHyMe..12..474G |doi-access = free }}</ref> as well as utilizing the tree-ring reconstruction of lake level change,<ref>{{cite journal |doi = 10.1016/j.jhydrol.2015.08.058 |volume = 529 |title = Added value from 576 years of tree-ring records in the prediction of the Great Salt Lake level |journal = Journal of Hydrology |year = 2015 |pages = 962–968 |last1 = Gillies |first1 = Robert R. |last2 = Chung |first2 = Oi-Yu |last3 = Simon Wang |first3 = S.-Y. |last4 = Derose |first4 = R. Justin |last5 = Sun |first5 = Yan |bibcode = 2015JHyd..529..962G |url = https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1007&context=wadr }}</ref> researchers were able to predict the lake level fluctuation onward for as long as 5–8 years.<ref>{{cite web|title=Great Salt Lake Annual Level Prediction|url=https://climate.usurf.usu.edu/GSL.php|url-status=dead|archive-url=https://web.archive.org/web/20150922005717/https://climate.usurf.usu.edu/GSL.php|archive-date=September 22, 2015|access-date=November 12, 2015|publisher=Utah Climate Center}}</ref>

The Great Salt Lake differs in elevation between the south and north parts. The causeway for the [[Lucin Cutoff]] divides the lake into two parts. The water-surface elevation of the south part of the lake is usually {{convert|0.5|to(-)|2|ft|cm}} higher than that of the north part because most of the inflow to the lake occurs from the south.<ref name="USGS-GSL"/><ref name="usgs-water-data-20160430-20170430" />

===Salinity===
Most of the salts dissolved in the lake and deposited in the desert flats around it reflect the concentration of solutes by [[evaporation]]; Lake Bonneville itself was fresh enough to support populations of fish.<ref name="pg03">{{cite web |url = http://www.ugs.state.ut.us/online/PI-39/pi39pg03.htm |title = Commonly Asked Questions About Utah's Great Salt Lake and Ancient Lake Bonneville |page = 3 |publisher = Utah Geological Survey |access-date = September 21, 2017 |archive-url = https://web.archive.org/web/20080422085735/http://www.ugs.state.ut.us/online/PI-39/pi39pg03.htm |archive-date = April 22, 2008 |url-status = dead }}</ref><ref>{{cite web |url = http://www.ugs.state.ut.us/online/PI-39/pi39pg02.htm |title = Commonly Asked Questions About Utah's Great Salt Lake and Ancient Lake Bonneville |page = 02 |publisher = Utah Geological Survey |access-date = September 21, 2017 |archive-url = https://web.archive.org/web/20080219074644/http://www.ugs.state.ut.us/online/PI-39/pi39pg02.htm |archive-date = February 19, 2008 |url-status = dead }}</ref> More salt is added yearly via rivers and streams, though the amount is much less than the [[relict (geology)|relict]] salt from Bonneville.<ref name="pg03"/>

The salinity of the lake's main basin, Gilbert Bay, is highly variable and depends on the lake's level; it ranges from 5 to 27% (50 to 270 [[concentration|parts per thousand]]).<ref name="Utah GS-Salt">{{Cite web |url = http://geology.utah.gov/online/PI-39/pi39pg9.htm |title = Can I float in Great Salt Lake? |archive-url = https://web.archive.org/web/20100815024315/http://geology.utah.gov/online/PI-39/pi39pg9.htm |archive-date = August 15, 2010 |publisher = Utah Geological Survey }}</ref> For comparison, the average salinity of the world ocean is 3.5% (35 parts per thousand)<ref>{{cite web |url = http://www.onr.navy.mil/Focus/ocean/water/salinity1.htm |title = Ocean Water: Salinity |access-date = July 31, 2007 |url-status = dead |archive-url = https://web.archive.org/web/20120306092046/http://www.onr.navy.mil/Focus/ocean/water/salinity1.htm |archive-date = March 6, 2012 }}</ref> and that of the [[Dead Sea]] is 33.7%. The [[ion]]ic composition is similar to seawater, much more so than the Dead Sea's water; compared to the ocean, the Great Salt Lake's waters are slightly enriched in [[potassium]] and depleted in [[calcium]].<ref name="Utah GS-Salt"/> Dissolved ions do not necessarily increase or decrease in step with changes of total dissolved solids. For example, in October 1903, dissolved solids tallied 27.72% and by February 1910 they were down to 17.68%, with chlorine, sodium and sulfate levels substantially lower, but over the same time calcium, magnesium and potassium ''increased'', with the increase of magnesium especially pronounced.<ref>{{cite journal|url=https://pubs.acs.org/doi/abs/10.1021/ie50023a005 |date=November 1910 |page=454|doi=10.1021/ie50023a005 |title=Comparative Analyses of Water from Great Salt Lake |last1=Ebaugh |first1=W. C. |last2=MacFarlane |first2=Wallace |journal=Journal of Industrial & Engineering Chemistry |volume=2 |issue=11 |s2cid=46706976 }}</ref>