Editing Drought (section)

== Categories ==
There are three major categories of drought based on where in the water cycle the moisture deficit occurs: meteorological drought, hydrological drought, and agricultural or ecological drought.<ref name=":2" />{{rp|1157}} A meteorological drought occurs due to lack of [[precipitation]]. A hydrological drought is related to low runoff, streamflow, and reservoir and groundwater storage.<ref>{{Cite journal|last=Van Loon|first=Anne F.|date=14 April 2015|title=Hydrological drought explained|url=https://wires.onlinelibrary.wiley.com/doi/10.1002/wat2.1085|journal=WIREs Water|volume=2|issue=4|pages=359–392|doi=10.1002/wat2.1085|bibcode=2015WIRWa...2..359V|issn=2049-1948}}</ref> An agricultural or ecological drought is causing plant stress from a combination of evaporation and low [[soil moisture]].<ref name=":2" />{{rp|1157}} Some organizations add another category: socioeconomic drought occurs when the demand for an economic good exceeds supply as a result of a weather-related shortfall in water supply.<ref name=":0" /><ref name=":32" /> The socioeconomic drought is a similar concept to [[water scarcity]].

The different categories of droughts have different causes but similar effects:
# [[Meteorology|Meteorological]] drought occurs when there is a prolonged time with less than average precipitation.<ref name="IGARSS2017">{{cite book|last1=Swain|display-authors=etal|first1=S|title=2017 IEEE International Geoscience and Remote Sensing Symposium (IGARSS)|chapter=Application of SPI, EDI and PNPI using MSWEP precipitation data over Marathwada, India|volume=2017|pages=5505–5507|doi=10.1109/IGARSS.2017.8128250|year=2017|isbn=978-1-5090-4951-6|s2cid=26920225}}</ref> Meteorological drought usually precedes the other kinds of drought.<ref name="NOAAsurprise">{{cite web|url=http://www.nws.noaa.gov/om/brochures/climate/Drought.pdf|archive-url=https://ghostarchive.org/archive/20221009/http://www.nws.noaa.gov/om/brochures/climate/Drought.pdf|archive-date=2022-10-09|url-status=live|title=What is a Drought?|date=August 2006|publisher=[[National Oceanic and Atmospheric Administration]]|access-date=2007-04-10}}</ref> As a drought persists, the conditions surrounding it gradually worsen and its impact on the local population gradually increases.
# [[Hydrology|Hydrological]] drought happens when water reserves available in sources such as [[aquifer]]s, [[lake]]s and [[reservoir]]s fall below average or a [[Descriptive statistics|locally significant]] threshold. Hydrological drought tends to present more slowly because it involves stored water that is used but not replenished. Due to the close interaction with water use, this type of drought is can be heavily influenced by [[water management]]. Both positive and negative human influences have been discovered and strategic water management strategies seem key to mitigate drought impact.<ref>{{Cite journal|last1=Van Loon|first1=Anne F.|last2=Stahl|first2=Kerstin|last3=Di Baldassarre|first3=Giuliano|last4=Clark|first4=Julian|last5=Rangecroft|first5=Sally|last6=Wanders|first6=Niko|last7=Gleeson|first7=Tom|last8=Van Dijk|first8=Albert I. J. M.|last9=Tallaksen|first9=Lena M. |last10=Hannaford |first10=Jamie|last11=Uijlenhoet|first11=Remko|last12=Teuling|first12=Adriaan J.|last13=Hannah|first13=David M.|last14=Sheffield|first14=Justin|last15=Svoboda|first15=Mark|date=2016-09-08|title=Drought in a human-modified world: reframing drought definitions, understanding, and analysis approaches|url=https://hess.copernicus.org/articles/20/3631/2016/|journal=Hydrology and Earth System Sciences|volume=20|issue=9|pages=3631–3650|doi=10.5194/hess-20-3631-2016|doi-access=free|bibcode=2016HESS...20.3631V|issn=1027-5606|hdl=1885/152821|hdl-access=free}}</ref><ref>{{Cite journal|last1=Wendt|first1=Doris E.|last2=Van Loon|first2=Anne F.|last3=Bloomfield|first3=John P.|last4=Hannah|first4=David M.|date=2020-10-13|title=Asymmetric impact of groundwater use on groundwater droughts|url=https://hess.copernicus.org/articles/24/4853/2020/|journal=Hydrology and Earth System Sciences|volume=24|issue=10|pages=4853–4868|doi=10.5194/hess-24-4853-2020|doi-access=free|bibcode=2020HESS...24.4853W|issn=1027-5606}}</ref> Like agricultural droughts, hydrological droughts can be triggered by more than just a loss of rainfall. For instance, around 2007 [[Kazakhstan]] was awarded a large amount of money by the [[World Bank]] to restore water that had been diverted to other nations from the [[Aral Sea]] under [[Soviet Union|Soviet]] rule.<ref>{{cite news|date=2007-04-09|title=Asia-Pacific – Dam project aims to save Aral Sea|publisher=BBC News|url=http://news.bbc.co.uk/2/hi/asia-pacific/6538219.stm}}</ref> Similar circumstances also place their largest lake, [[Lake Balkhash|Balkhash]], at risk of completely drying out.<ref>{{cite news|date=2004-01-15|title=Asia-Pacific – Kazakh lake 'could dry up'|publisher=BBC News|url=http://news.bbc.co.uk/2/hi/asia-pacific/3397077.stm}}</ref>
# [[Agriculture|Agricultural]] or ecological droughts affect crop production or [[ecosystem]]s in general. This condition can also arise independently from any change in precipitation levels when either increased [[irrigation]] or [[soil]] conditions and erosion triggered by poorly planned agricultural endeavors cause a shortfall in water available to the crops.