Information

What is "HexWatershed"?

HexWatershed is a mesh-independent flow direction model for hydrologic models.

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:

1. It cannot represent adjacency uniformly.

2. It leads to the "island effect" and the diagonal travel path issue in the D8 scheme.

3. It cannot provide a spherical coverage without significant spatial distortion.

4. It cannot be coupled with other unstructured mesh-based models, such as the oceanic models.

5. Therefore, we developed a watershed delineation model (HexWatershed) based on the hexagon mesh spatial discretization. 

6. We further improve HexWatershed to an unstructured mesh-based approach 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 rewrote all the core watershed delineation algorithms on a completely different data structure.

And, we invented several new advanced algorithms, such as the stream burning-seeded priority flood algorithm.

What is the current status of "HexWatershed"?

We are adding more features to the HexWatershed ecosystem, please check the GitHub discussion and issue.