The large-scale water management (WM) model , coupled with the river routing model MOSART, simulates 'regulated" river flow through the representation of spatially distributed water extractions based on local water demands, and flow regulations at dams. The water demand that cannot be met locally at each grid cell, is allocated across reservoirs based on elevation constraints, reservoir capacity, and water availability. For the flow regulation module, each reservoir operating rules are calibrated based on historical long-term mean monthly inflow and associated water demand, reservoir characteristics, reservoir purpose (flood control, irrigation, combination of flood control and irrigation, other). The regulation includes minimum release for environmental flow. Reservoir operations have a monthly pattern that is shifted to represent inter-annual variability in water availability. Releases are further adjusted at a daily time scale (or shorter) to account for reservoir characteristics constraints (minimum storage, maximum capacity, minimum flow release). The WM model has been shown to represent seasonal variations in regulated river flows across the U.S. and is similar to other large-scale water management applications in terms of handling water withdrawal and dam operations. The specificity of WM is its coupling with the river routing model MOSART, the use of storage targets to combine flood control and irrigation operating rules, and the accounting for unmet demand (supply deficit). The model is an integration platform for land surface models to interact with integrated assessment models such as the Global Climate Assessment Model and assess the sustainability and resilience of environmental systems to changes in natural conditions and human activities ( sectoral water demands).