Editing Spring (hydrology) (section)

==Water content==
{{Main|Mineral spring}}
[[File:PruessLake.JPG|thumb|[[Pruess Lake]] is spring-fed in the arid [[Snake Valley (Great Basin)|Snake Valley]] of [[Utah]].]]
[[Mineral]]s become dissolved in the water as it moves through the underground [[rock (geology)|rocks]]. This mineral content is measured as [[total dissolved solids]] (TDS). This may give the water flavor and even [[carbon dioxide]] bubbles, depending on the nature of the [[geology]] through which it passes. This is why spring water is often bottled and sold as [[mineral water]], although the term is often the subject of [[deception|deceptive]] [[advertising]]. Mineral water contains no less than 250 parts per million (ppm) of tds. Springs that contain significant amounts of minerals are sometimes called '[[mineral springs]]'. (Springs without such mineral content, meanwhile, are sometimes distinguished as 'sweet springs'.) Springs that contain large amounts of dissolved [[sodium]] [[salts]], mostly [[sodium carbonate]], are called 'soda springs'. Many resorts have developed around mineral springs and are known as [[spa towns]]. Mineral springs are alleged to have healing properties. Soaking in them is said to result in the absorption of the minerals from the water. Some springs contain [[arsenic]] levels that exceed the 10 ppb [[World Health Organization]] (WHO) standard for [[drinking water]].<ref name=likang /> Where such springs feed rivers they can also raise the arsenic levels in the rivers above WHO limits.<ref name=likang>{{cite journal |last1= Li|first1= Chaoliu|last2= Kang|first2= Shichang|last3= Chen|first3= Pengfei|last4= Zhang|first4= Qianggong|last5= Mi|first5= Jue|last6= Gao|first6= Shaopeng|last7= Sillanpää|first7= Mika|title=Geothermal spring causes arsenic contamination in river waters of the southern Tibetan Plateau, China|url= |journal= Environmental Earth Sciences|year= 2014|volume= 71|issue= 9|pages= 4143–4148|doi=10.1007/s12665-013-2804-2|bibcode= 2014EES....71.4143L|s2cid= 128479153|access-date=}}</ref>

Water from springs is usually clear. However, some springs may be colored by the minerals that are dissolved in the water. For instance, water heavy with iron or [[tannins]] will have an orange color.<ref name="USGS"/>

In parts of the United States a [[stream]] carrying the outflow of a spring to a nearby primary stream may be called a '''spring branch''', [[spring creek]], or run. Groundwater tends to maintain a relatively long-term average temperature of its aquifer; so flow from a spring may be cooler than other sources on a summer day, but remain unfrozen in the winter. The cool water of a spring and its branch may harbor species such as certain [[trout]] that are otherwise ill-suited to a warmer local [[climate]].

===Types of mineral springs===
[[File:Natural iron hot spring.jpg|thumb|upright|Natural iron hot spring in [[Beppu Onsen|Beppu]], Japan]]
* Sulfur springs contain a high level of dissolved [[sulfur]] or hydrogen sulfide in the water. Historically they have been used to alleviate the symptoms of arthritis and other inflammatory diseases.<ref name="CGS">{{cite journal |last1=Pearl |first1=Richard Howard |last2=Ringrose |first2=Charles D. |last3=Zacharakis |first3=Ted G. |title=Geothermal Resource Assessment of Hot Sulphur Springs, Colorado |journal=Colorado Geological Survey |date=1982 |url=https://books.google.com/books?id=5F9OAQAAIAAJ |access-date=14 November 2021}}</ref><ref name="EIW">{{cite web |last1=Gemici |first1=Burcu |last2=Wallace |first2=John L. |title=Encyclopedia of Inland Waters |url=https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/sulfur-springs |access-date=15 November 2021}}</ref>
* Borax springs<ref name="ISB">{{cite book |last1=Zakrajsek |first1=John R. |title=Identifying Systematic Behaviors in Borax Lake Geothermal Springs, Southeast Oregon |date=2006 |publisher=University of Idaho |url=https://books.google.com/books?id=wrmYPgAACAAJ |access-date=14 November 2021}}</ref> 
* Gypsum springs<ref name="Classification" />
* Saline springs<ref name="TCN">{{cite book |last1=Bischoff |first1=Matt C. |title=Touring California and Nevada hot springs |date=2018 |publisher=Falcon Guides |location=Guilford, Connecticut |isbn=9781493029112 |url=https://books.google.com/books?id=I2tMDwAAQBAJ |access-date=14 November 2021}}</ref>
* [[chalybeate|Iron springs (chalybeate spring)]]<ref name="Classification" />
* Radium springs (or radioactive springs) have a detectable level of radiation produced by the natural radioactive decay process<ref name="NatRad">{{cite journal |last1=Leonard |first1=Robert B. |last2=Janzer |first2=Victor J. |title=Natural radioactivity in geothermal waters, Alhambra Hot Springs and nearby areas, Jefferson County, Montana |journal=Journal of Research of the U.S. Geological Survey |date=July–August 1978 |volume=6 |issue=4 |url=https://pubs.usgs.gov/journal/1978/vol6issue4/report.pdf |access-date=14 November 2021}}</ref><ref name="Dictionary of Hydrogeology" />