The recent Delft Software Days saw the release of wflow 2019.1, the latest evolution of Deltares open source distributed hydrological modelling software. Our wflow software has seen considerable growth in implementation over 2019 with it being increasingly used to compute river flows for water resources and flood studies in Africa, Americas, Asia and Europe.

The wflow framework, built in PCRaster Python can be adapted by modellers for their specific needs.  Currently the framework has been adapted to allow users to select and adapt different conceptual hydrological models such as the classic HBV-96 model, the SPHY model, the PCRGLOB-WB model and the SBM model concept, amongst others.

The latest release includes a revised lateral subsurface flow method in the SBM model to correct the previous overestimation. A new and faster kinematic wave solution has been added with the ability to have smaller timesteps for surface runoff in the HBV and SBM models. Additionally, the new kinematic wave approach is separated for overland and river flows providing better representation of the runoff process in the SBM model. In SBM the lateral subsurface and overland flow now feed into the surface water network based on slope. W3, an improved version of the W3RA model concept, and the STREAM (Spatial Tools for River Basins and Environment and Analysis of Management Options) concept, have been added to the framework.

The 2019.1 release also includes an experimental module to simulate soil erosion and delivery to the river system. The new water quality module provides a set of functions to create and link a Delft3D-WAQ or D-Emission model to a wflow model. We have also updated the functionality to model lakes using a Modified Puls Approach. There is an updated glacier module to simulate melt water generation. The surface roughness parameter, Manning N, for rivers can now be linked to streamorder for use in the HBV and SBM concept. Additionally, the sub-grid runoff generation and re-infiltration features have been removed in the SBM concept.

If you want the latest software release or more information on how wflow can support your hydrological modelling, contact wflow@deltares.nl or visit our website.