Hydrography90m: pushing the boundaries of computational hydrology

Streams and rivers drive several processes in hydrology, geomorphology, geography and ecology. A global standardized
hydrographic network that accurately delineates streams and rivers, along with their topographic and topological properties, is needed
for worldwide environmental applications. Using the MERIT Hydro Digital Elevation Model at 90m and by employing a suite of GRASS
GIS hydrological modules, we calculated the range-wide upstream flow accumulation and flow direction to delineate a total of 1.6 million
drainage basins and extracted globally a total of 726 million unique stream segments with their corresponding sub-catchments.
Besides, stream topographic variables comprising stream slope, gradient, length, and curvature attributes as well as stream topological
variables to allow for network routing and various stream order classifications were computed. The validation shows that the newly
developed Hydrography90m has the highest spatial precision and contains more headwater stream channels compared to three other
global hydrographic datasets. More information at doi.org/10.519...