In the Netherlands, suitable water allocation decisions are required to ensure fresh water availability under dry conditions, now and in the future. A high-resolution integrated surface-and groundwater of the Netherlands, called the National Hydrological Model, exists to support water management decisions on a national scale. Given the run times of this model, it is less suited to accommodate screening of water allocation alternatives that deviate from the common practice. Therefore, policy makers and operational water managers within the Ministry of Infrastructure and Environment felt the need for a tool that can assist in the screening of alternative water allocation strategies. This Quick Scan Tool uses a coarse scale network model of the Netherlands water system to compute the water allocation pattern given water demands and boundary conditions as provided by the National Hydrological Model. To accommodate the priority based water allocation policies commonly used in the Netherlands, a lexicographic goal programming technique is used to solve the water allocation problem. The tool has been developed using RTC-Tools 2 as computation engine and Delft-FEWS as a front-end, where Delft-FEWS is also responsible for workflow and data management. This paper presents the Quick Scan Tool developed, including the mathematical techniques used and the validation of the results against the allocations computed by the National Hydrological Model.