General Information


This website is created for distribution of GWD-LR version 1.2
Previous version (v1.1) can be downloaded from here

Please e-mail to the developer for the password for downloading the GWD-LR. The sample source code of the Global River Width Algorithm which was used for GWD-LR is also available on request.



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.


Terms and Conditions

Agreement to Terms and Conditions is required for using G3WBM.
Please note that GWD-LR is provided for free of charge, only for non-commertial academic purposes (research and education). Permission is needed if GWD-LR is used for other purposes (e.g. commercial use).
Please e-mail to the developer to acquire password for downloading GWD-LR. Please describe your name, research institute, and purpose of using GWD-LR in the e-mail.

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]].