Create hydrological sub-basins for water risk calculation using various levels of HydroBASINS.

Water related risk metrics are often calculated by aggregating pixel data to a hydrological sub-basin unit. The HydroBASIN dataset can be used for this but has limitation. For many of the water related stress metrics, it is assumed that water resources are pooled (shared) within each sub-basin. Using the default HydroBASIN, this assumption will not hold in the following cases:

Streams cannot bifurcate in the HydroBASIN and HydroSHEDS datasets leading to inaccurate representation of deltas.

Coastal regions and islands are often grouped into a single multipolygon. The hydrology however, is often not connected leading to erroneous results.

In this repo, we develop an approach to address some of these issues by combining several levels of HydroBASIN data, apply a few GIS processing steps and finally group delta regions.

The result is a database that addresses some of the major limitations of the default HydroBASINS data.

TBD