What is "HexWatershed"?
HexWatershed is a hydrologic routing model based on the hexagon/unstructured mesh framework.
Why do we develop HexWatershed?
Spatial discretization is the cornerstone of all spatially-distributed numerical simulations including watershed hydrology. Traditional square grid spatial discretization has several limitations:
It cannot represent adjacency uniformly;
It leads to the "island effect" and the diagonal travel path issue in D8 scheme;
It cannot provide a spherical coverage without significant spatial distortion.
Therefore, we developed a watershed delineation model (HexWatershed) based on the hexagon mesh spatial discretization.
We further improve HexWatershed to fully unstructured mesh-based to support variable-resolution meshes such as the MPAS mesh.
We propose that spatially distributed hydrologic simulations should consider using a hexagon grid spatial discretization.
How we did it?
We basically rewrote all the core watershed delineation algorithms, just on a completely different data structure.
What is the current status of "HexWatershed"?
We are finalizing a few core components in the HexWatershed ecosystem:
A special designed resampling tool for HexWatershed will be available soon;
HexWatershed is ready for continental and global scale simulation;
HexWatershed is supporting MPAS mesh;
We are evaluating hydrology simulations using HexWatershed routing maps.
Chang Liao, Tian Zhou, Donghui Xu, Richard Barnes, Gautam Bisht,
Liao, C., Tesfa, T., Duan, Z., & Leung, L. R. (2020). Watershed delineation on a hexagonal mesh grid. Environmental Modelling & Software, 104702. https://doi.org/10.1016/j.envsoft.2020.104702