Data name: 
MERIT Hydro
Data Category: 
topography
Data Keywords: 
BASIN
RIVER
RIVER NETWORK
HYDROLOGY
WATER
Data Last Access: 
Tuesday, 8 October, 2019
Data JRC Contact Info: 
cesar.carmona-moreno@ec.europa.eu
Data Credits: 
Underwood, E. (2019), A more accurate global river map, Eos, 100, https://doi.org/10.1029/2019EO128033. Yamazaki, D., Ikeshima, D., Sosa, J., Bates, P. D., Allen, G. H., & Pavelsky, T. M. (2019). MERIT Hydro: a high‐resolution global hydrography map based on latest topography dataset. Water Resources Research, 55, 5053–5073. https://doi.org/10.1029/ 2019WR024873
Data Availability: 
REGISTRATION REQUIRED
Data Use Limitations: 
The MERIT Hydro is licensed under a Creative Commons "CC-BY-NC 4.0" or Open Data Commons "Open Database License (ODbL 1.0)". (i.e. dual license, you can choose an appropriate license for you)
Data temporal frequency: 
none
Data Spatial Extent: 
Data Region of Interest: 
World
Data Short Description: 
Map of global river systems is based on crowdsourcing and the latest topography data sets.
Data Extended Description: 
High-resolution raster hydrography maps are a fundamental data source for many geoscience applications. Here we introduce MERIT Hydro, a new global flow direction map at 3 arc-second resolution (~90 m at the equator) derived from the latest elevation data (MERIT DEM) and water body datasets (G1WBM, GSWO, and OpenStreetMap). We developed a new algorithm to extract river networks near-automatically by separating actual inland basins from dummy depressions caused by the errors in input elevation data. After a minimum amount of hand-editing, the constructed hydrography map shows good agreement with existing quality-controlled river network datasets in terms of flow accumulation area and river basin shape. The location of river streamlines was realistically aligned with existing satellite-based global river channel data. Relative error in the drainage area was smaller than 0.05 for 90% of GRDC gauges, confirming the accuracy of the delineated global river networks. Discrepancies in flow accumulation area were found mostly in arid river basins containing depressions that are occasionally connected at high water levels and thus resulting in uncertain watershed boundaries. MERIT Hydro improves on existing global hydrography datasets in terms of spatial coverage (between N90 and S60) and representation of small streams, mainly due to increased availability of high-quality baseline geospatial datasets. The new flow direction and flow accumulation maps, along with accompanying supplementary layers on hydrologically adjusted elevation and channel width, will advance geoscience studies related to river hydrology at both global and local scales. See URLs for more datails.