Editing IPCC:AR6/WGI/Chapter-11 (section)

==== 11.6.1.4 Hydrological Deficits ====

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Drivers of streamflow and surface water deficits are complex and strongly depend on the hydrological system analysed (e.g., streamflows in the headwaters, medium course of the rivers, groundwater, highly regulated hydrological basins). Soil hydrological processes, which control the propagation of meteorological droughts throughout different parts of the hydrological cycle ( [[#Van%20Loon--2012|Van Loon and Van Lanen, 2012]] ), are spatially and temporally complex ( [[#Herrera-Estrada--2017|Herrera-Estrada et al., 2017]] ; S. [[#Huang--2017|Huang et al., 2017]] b) and difficult to quantify ( [[#Van%20Lanen--2016|Van Lanen et al., 2016]] ; [[#Apurv--2017|Apurv et al., 2017]] ; [[#Caillouet--2017|Caillouet et al., 2017]] ; [[#Konapala--2017|Konapala and Mishra, 2017]] ; [[#Hasan--2019|Hasan et al., 2019]] ). The physiographic characteristics of the basins also affect how droughts propagate throughout the hydrological cycle ( [[#Van%20Loon--2012|Van Loon and Van Lanen, 2012]] ; [[#Van%20Lanen--2013|Van Lanen et al., 2013]] ; [[#Van%20Loon--2015|Van Loon, 2015]] ; [[#Konapala--2020|Konapala and]] [[#Mishra--2020|Mishra, 2020]] ; Veettil and [[#Mishra--2020|Mishra, 2020]] ). In addition, the assessment of groundwater deficits is very difficult given the complexity of processes that involve natural and human-driven feedbacks and interactions with the climate system ( [[#Taylor--2013|Taylor et al., 2013]] ). Streamflow and surface water deficits are affected by land cover, groundwater and soil characteristics ( [[#Van%20Lanen--2013|Van Lanen et al., 2013]] ; [[#Van%20Loon--2015|Van Loon and Laaha, 2015]] ; [[#Barker--2016|Barker et al., 2016]] ; [[#Tijdeman--2018|Tijdeman et al., 2018]] ), as well as human activities (water management and demand, damming) and land-use changes ( [[#11.6.4.3|Section 11.6.4.3]] ; [[#Van%20Loon--2016|Van Loon et al., 2016]] ; [[#He--2017|He et al., 2017]] ; [[#Veldkamp--2017|Veldkamp et al., 2017]] ; J. [[#Wu--2018|]] [[#Wu--2018|Wu et al., 2018]] ; Y. [[#Xu--2019|]] [[#Xu--2019|Xu et al., 2019]] ; [[#Jehanzaib--2020|Jehanzaib et al., 2020]] ). Finally, snow and glaciers are relevant for water resources in some regions. For instance, warming affects snowpack levels ( [[#Dierauer--2019|Dierauer et al., 2019]] ; [[#Huning--2020|Huning and AghaKouchak, 2020]] ), as well as the timing of snow melt, thus potentially affecting the seasonality and magnitude of low flows ( [[#Barnhart--2016|Barnhart et al., 2016]] ).

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