Global modeling of withdrawal, allocation and consumptive use of surface water and groundwater resources

摘要

To sustain growing food demand and increasing standard of living, globalwater withdrawal and consumptive water use have been increasing rapidly. Toanalyze the human perturbation on water resources consistently over largescales, a number of macro-scale hydrological models (MHMs) have beendeveloped in recent decades. However, few models consider the interactionbetween terrestrial water fluxes, and human activities and associated wateruse, and even fewer models distinguish water use from surface water andgroundwater resources. Here, we couple a global water demand model with aglobal hydrological model and dynamically simulate daily water withdrawaland consumptive water use over the period 1979–2010, using two re-analysisproducts: ERA-Interim and MERRA. We explicitly take into account the mutualfeedback between supply and demand, and implement a newly developed waterallocation scheme to distinguish surface water and groundwater use.Moreover, we include a new irrigation scheme, which works dynamically with adaily surface and soil water balance, and incorporate the newly availableextensive Global Reservoir and Dams data set (GRanD). Simulated surface water andgroundwater withdrawals generally show good agreement with reported nationaland subnational statistics. The results show a consistent increase in bothsurface water and groundwater use worldwide, with a more rapid increase ingroundwater use since the 1990s. Human impacts on terrestrial water storage(TWS) signals are evident, altering the seasonal and interannualvariability. This alteration is particularly large over heavily regulatedbasins such as the Colorado and the Columbia, and over the major irrigatedbasins such as the Mississippi, the Indus, and the Ganges. Including humanwater use and associated reservoir operations generally improves thecorrelation of simulated TWS anomalies with those of the GRACE observations.