GWD-LR: Global Width Database of Large Rivers

Last Update: 15 Oct, 2018


General Information


GWD-LR v1.2 (distributed in this webpage) is an old version.
The latest river width map is distributed as a component of MERIT Hydro.
Please visit MERIT Hydro webpage to get an access.



River width is a fundamental parameter of river hydrodynamic simulations, but to date no global-scale river width database based on observed water bodies has been available. Here we present a new algorithm that automatically calculates river width from satellite-based water masks and flow direction maps. The Global Width Database for Large Rivers (GWD-LR) is developed by applying the algorithm to the SRTM Water Body Database and the HydroSHEDS flow direction map. Both bank-to-bank river width and effective river width excluding islands are calculated for river channels between 60S and 60N. The effective river width of GWD-LR is compared with existing river width databases for the Congo and Mississippi Rivers. The effective river width of the GWD-LR is slightly narrower compared to the existing databases, but the relative difference is within ?}20% for most river channels. As the river width of the GWD-LR is calculated along the river channels of the HydroSHEDS flow direction map, it is relatively straightforward to apply the GWD-LR to global- and continental-scale river modeling.


Development of the Global Width Database for Large Rivers
-- Dai Yamazaki, Fiachra O'Loughlin, Mark A. Trigg, Zachary F. Miller, Tamlin M. Pavelsky, & Paul D. Bates
-- Absstract in WRR
-- Water Resour. Res., vol.50, pp.3467-3480, 2014, DOI: 10.1002/2013WR014664

Data Description

Description Document

Please download the description document for the GWD-LR version 1.2

Data Format

The GWD-LR represents effective river width (excluding islands). The original resolution of GWD-LR is 3 arc-sec (~90m), but the version in this website is upscaled to 1/200, 1/40, 1/10, 1/4, 1/2. The coverage of the GWD-LR is between 80N and 60S.

The data format is 'Fortran Direct Access Format' (i.e. ESRI 'BIL/BSQ/FLT' raster format with the HDR file, GrADS binary with CTL file).
Detailed description of the data format is available in the description document.

Use of Data

License Agreement

The GWD-LR is licensed under a Creative Commons Attribution 4.0 International License (CC-BY 4.0). To view a copy of this license, please visit By downloading and using the data the user agrees to the terms and conditions of this license. Notwithstanding this free license, we ask users to refrain from redistributing the data in whole in its original format on other websites without the explicit written permission from the authors. GWD-LR is available for download at The copyright of GWD-LR is held by the developers, 2018, all rights reserved.

Data sharing policy

Citation to the paper is adequate if you simply use the G3WBM/G1WBM. If you asked help for additional handling/editing of the dataset, or your research outcome highly depends on the product, the developer would request co-authorship.

Registration for Download

Please fill the Google Form to get an access to GWD-LR

or please contact to the developer (yamadai [at] to get an access.


Global-coverage Data

Global coverage data is available at three different resolutions.
Please e-mail the developer for the password required for downloading
-- download 1/40 deg data

-- download 1/10 deg data

-- download 1/4 deg data

-- download 1/2 deg data

Regional 0.005 deg (1/200 deg) Data

The 0.005 degree data is divided into 14 regions. Please see the description document for detail.
-- download 0.005 degree data


Original 3sec Data

Please contact to the developer (Dai Yamazaki) if you are interested in the original 3sec (90m) data.


Global River Width Algorithm

GWD-LR is generated by applying the Global River Width Algorithm (GRW Algorithm) to SWBD and HydroSHEDS. The detailed explanation on the GWD Algorithm is summarized in the document. download the GRW Algorithm document.

The Fortran90 code with sample datasets can be downloaded. Download the code [[password required]].