QUAlloc is a globally applicable water use and allocation model that distributes the water demands to the water availability from different sources while considering the water quality requirements for the main water use sectors: domestic, irrigation, livestock, manufacturing and energy. QUAlloc is a high-resolution global-scale model with 10 km (5 arcmin) spatial resolution and a flexible temporal resolution (i.e., daily, monthly or yearly).

QUAlloc considers the changing of long-term water availability and water quality to meet the demand over time and evaluates how short-term variations in supply and demand may require adjustments to minimize any shortfalls per sector. Optionally, QUAlloc considers the spatial distribution of water at any moment in time, aspects of the water infrastructure in terms of the network of sources and sinks, limiting abstraction potentials (i.e., pumping capacities), and water management considerations by prioritizing the order in which demands are met.

QUAlloc is built up on the global hydrological model PCR-GLOBWB2 (Sutanudjaja et al., 2018; https://github.com/UU-Hydro/PCR-GLOBWB_model) and the global surface water quality model DynQual (Jones et al., 2023; https://github.com/SustainableWaterSystems/DYNQUAL).

Currently, QUAlloc has a stand-alone modelling configuration with user-defined water demands, requiring hydrological and water quality input data. The model input files are:

• water availability (obtained from PCR-GLOBWB2): discharge, total runoff, direct runoff, interflow, baseflow, channel storage, groundwater storage, groundwater recharge and returns flow.
• water quality (obtained from DynQual): surface water temperature, biochemical oxygen demand, total dissolved solids, faecal coliforms.

The main output files from QUAlloc are the water withdrawals and allocation volumes per water source (i.e., surface water, renewable groundwater and non-renewable groundwater) and per sector (i.e., domestic, irrigation, livestock, manufacturing and thermoelectric).

Please note that QUAlloc is still being actively developed (Cardenas Belleza et al, in review).