2.1.1 Human water use (HWR)
The scheme of HWR was incorporated into CAS-LSM as a sub-model (Zou et
al. 2015; Zeng, Xie and Liu 2017). The HWR mainly considered withdrawal
due to groundwater pumping, in which the estimated groundwater pumping
rate from aquifers was apportioned among agricultural, industrial and
domestic use. The industrial and domestic consumptions had two
components, where the wastewater produced by industry and human daily
life was treated as a discharge into local rivers and the net water
consumption was treated as evaporation to the atmosphere. The aquifer
recharge rate was updated by subtracting the GW extraction rate from the
original aquifer recharge rate; for irrigation consumption, the net
water input rate was timed as the ratio of the agricultural consumption
rate and added to the top of the soil’s surface. The pumping rate and
the other ratios were determined by forcing data combined from three
data sources, including the Food and Agriculture Organization of the
United Nations (FAO) global water information system
(http://www.fao.org/nr/water/aquastat/main/index.stm),
the Global Map of Irrigation Areas, version 5.0 (Siebert et al. 2005,
2013), and the historical monthly soil moisture and saturated soil
moisture simulated by CLM4.5 offline using the atmospheric forcing data
set described by Qian et al. (2006) for the years 1965–2000.