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Catalog datasets represent a fraction of data in use by active WMA projects. The team is working on including more datasets to provide a complete view of data-in-use. Let us know how your experience is!

Datasets

MERIT Hydro: Global Hydrography Datasets

Domain: Hydrology

Variables: Elevation; Flow direction; Hydrosheds; River-width; Upstream drainage area

Spatial Resolution: 3 arc second

Temporal Frequency: NA

Temporal Coverage: 2019

Spatial Extent: Global

Source: Academic Institution

Update Type: Dynamic

Update Frequency: unknown

Update Detail: append and modify

Access:

Access Details:

Please fill out the Google Form for registration & license agreement. The password for downloading is emailed after registration, or please contact to the developer (yamadai [at] iis.u-tokyo.ac.jp) to get an access.

Description:

High-resolution raster hydrography maps are a fundamental data source for many geoscience applications. MERIT Hydro is 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). This dataset uses 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.

Citation:

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 datasets Water Resources Research, vol.55, pp.5053-5073, accessed [YYYY-MM-DD] at https://doi.org/10.1029/2019WR024873