Project PI: Kimberley McCormack, NGA

In this project, NGA will provide global foundational datasets to serve as inputs to the various models in the inter-agency hydrology modeling framework referred to as the Poseidon Project. This includes TanDEM-X Temporary (TDT), a global digital elevation model (DEM) with 12 meter resolution. Additionally, NGA will provide a suite of products derived from TDT, including a hydrologically conditioned DEM, flow direction and accumulation rasters, stream networks, and coupled hydrologic basins. These datasets promote consistency between Poseidon models and improve resolution compared to currently available datasets. Previously, the best available global hydrologically conditioned DEM has a resolution of 90m. The TanDEM-X hydrologically conditioned DEM will be a dramatic improvement and allow for the best-available datasets to be leveraged for a wide array of hydrologic applications.

The primary codes for this project are DEM processing algorithms built by NGA scientists, along with the open-source TauDEM and gdal software packages. The process reads in geotiff-formatted elevation tiles (1 degree x 1 degree), along with raster datasets for surface water occurrence, hydrologically conditions the DEM data, and calculates the global hydrography based on the conditioned DEM.