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Filling a Global Data Need for Surface Runoff and River Flow Data

Posted by Jenn Collins on May 10, 2021

The availability of detailed surface runoff and river flow data across large geographic areas is crucial for diverse applications.  Only a few countries have such data at a high resolution (HR).  Paucity of detailed input spatial data and challenges with intense processing were the limiting factors in developing HR surface runoff and river flow datasets over large spatial scales.  USDA’s well-established Curve Number (CN) method was applied as a spatially distributed hydrologic modeling approach to estimate surface runoff.  HR global datasets for hydrologic soil groups, land cover, and precipitation were spatially processed by applying the CN equations to create a contiguous global mean annual surface runoff grid at a HR of approximately 50 meters.  Surface runoff was spatially combined with detailed global hydrology of catchments and rivers from HydroBASINS and HydroRIVERS to estimate mean annual flows across the global river network, which includes about 1 million river segments covering the globe.  Estimated river flows were compared with measured gauge flows across several countries showing good correlation between estimated and measured flows.  The river flows will be made publicly available and can be extracted for use over large regions or small watersheds across the globe.

Stay tuned to our future newsletter for release of the global river flow data and publication describing this complex dataset’s creation!