Simulating human impacts on global water resources using VIC-5

Abstract

Abstract. Questions related to historical and future water resources and scarcity have been addressed by several macroscale hydrological models. One of these models is the Variable Infiltration Capacity (VIC) model. However, further model developments were needed to holistically assess anthropogenic impacts on global water resources using VIC. Our study developed VIC-WUR, which extends the VIC model using (1) integrated routing, (2) surface and groundwater use for various sectors (irrigation, domestic, industrial, energy, and livestock), (3) environmental flow requirements for both surface and groundwater systems, and (4) dam operation. Global gridded datasets on sectoral demands were developed separately and used as an input for the VIC-WUR model. Simulated national water withdrawals were in line with reported Food and Agriculture Organization (FAO) national annual withdrawals (adjusted R2 > 0.8), both per sector and per source. However, trends in time for domestic and industrial water withdrawal were mixed compared with previous studies. Gravity Recovery and Climate Experiment (GRACE) monthly terrestrial water storage anomalies were well represented (global mean root-mean-squared error, RMSE, values of 1.9 and 3.5 mm for annual and interannual anomalies respectively), whereas groundwater depletion trends were overestimated. The implemented anthropogenic impact modules increased simulated streamflow performance for 370 of the 462 anthropogenically impacted Global Runoff Data Centre (GRDC) monitoring stations, mostly due to the effects of reservoir operation. An assessment of environmental flow requirements indicates that global water withdrawals have to be severely limited (by 39 %) to protect aquatic ecosystems, especially with respect to groundwater withdrawals. VIC-WUR has potential for studying the impacts of climate change and anthropogenic developments on current and future water resources and sector-specific water scarcity. The additions presented here make the VIC model more suited for fully integrated worldwide water resource assessments.

Worldwide water constraints on attainable irrigated production for major crops

“…interception, evapotranspiration, percolation, and surface and subsurface runoff; [31,32]) and anthropogenic wateruse (i.e. domestic, industrial, energy, livestock and irrigation withdrawal and consumption; [33]). VIC has been used extensively in studies ranging from global streamflow simulations and hydrological climate sensitivity [36][37][38] to anthropogenic impacts of irrigation and dam operation on water resources [33,[39][40][41][42].…”

“…domestic, industrial, energy, livestock and irrigation withdrawal and consumption; [33]). VIC has been used extensively in studies ranging from global streamflow simulations and hydrological climate sensitivity [36][37][38] to anthropogenic impacts of irrigation and dam operation on water resources [33,[39][40][41][42]. WOFOST is a field-scale crop model that simulates daily crop growth (e.g.…”

Simulating the Impact of Global Reservoir Expansion on the Present‐Day Climate

“…In these models, reservoirs are commonly integrated in the river network and their operation is simulated through schemes in which release is determined by operation rules based on the reservoir purpose (Haddeland et al., 2006; Hanasaki et al., 2006). The use of these outflow schemes in global hydrological models allows for the estimation of large‐scale impacts of reservoirs on the hydrological cycle, under prescribed meteorological forcing (Biemans et al., 2011; Döll et al., 2009; Droppers et al., 2020; Hanasaki et al., 2008; Masaki et al., 2017; Shin et al., 2020; Van Beek et al., 2011; Voisin et al., 2013; Wisser et al., 2010). Recent efforts have adapted and/or coupled these schemes to simulate the effects of reservoir operation on river discharge in LSMs (Nazemi & Wheater, 2015; Pokhrel et al., 2016).…”

Extending a Large-scale Model to Better Represent Water Resources without Increasing the Model Complexity

“…A better representation of groundwater processes needs to be included in large-scale hydrological models to improve simulations and the understanding of feedbacks between the human and natural systems [8 -10]. Simple one-dimensional groundwater routines currently exist within HiGW-MAT (Human Intervention and Ground Water coupled MATSIRO) [9], H08 [11], PCR-GLOBWB [12], CWatM [13], WaterGAP [14] and VIC [15], with the focus on quantity and change in groundwater storage. Most models allow for groundwater to be recharged through rainfall, wetlands and reservoirs.…”