wflow is Deltares’ solution for modelling hydrological processes, allowing users to account for precipitation, interception, snow accumulation and melt, evapotranspiration, soil water, surface water and groundwater recharge in a fully distributed environment. Successfully applied worldwide for analyzing flood hazards, drought, climate change impacts and land use changes, wflow is growing to be a leader in hydrology solutions. wflow is also being used for flood warning systems with the Delft-FEWS framework, providing timely and accurate flow forecasting.

wflow is a completely distributed modelling platform which maximizes the use of open earth observation data, making it the hydrological model of choice for data scarce environments. Based on gridded topography, soil, land use and climate data, wflow calculates all hydrological fluxes at any given point in the model at a given time step. The movement of surface water across the landscape is determined by the reservoir and kinematic wave modules providing more accurate representation of river discharges.

The wflow framework is open source and flexible, and is increasingly being used in conjunction with other models to provide river flow data for water quality assessments, hydrodynamic simulations for flood risk analysis and with water allocation models to assess water management strategies. wflow is the key component of the D-Hydrology module and has been successfully coupled with the D-Flow FM and D-Water Quality (DELWAQ) modules of the Delft3D FM Suite (1D/2D/3D modelling suite for integral water solutions) and RIBASIM (water allocation). It can be provided within the Deltares Software Service and Support Packages.

As wflow uses the Python language as its basis, it has a transparent structure that can be adapted by modellers for their specific needs. This flexibility provides for easy integration with other models. Currently the framework has been adapted to allow users to select and adapt different conceptual hydrological models such as the classic HBV model, the W3RA model and the SBM model concept, amongst others.