Summary

GRDC Major River Basins of the World (MRB) is an ongoing GIS project of the Global Runoff Data Centre (GRDC). It is provided for public use under the condition of full citation and reference to incorporated data from the HydroSHEDS database (Lehner 2013). This is the 2nd, revised edition 2020 and replaces the basin polygons and river lines of the edition 2007 (GRDC 2007).

The “Major River Basins” and “Major River Networks” layers represent 520 river/lake basins considered “major” in basin size, or in their hydro-political importance or interest. They refer to a hydrological determination of a drainage basin by a common outlet to which all waters flow (i.e. pour point in GIS). Major River Basins may be basins with exorheic drainage, wherein all waters flow to a common outlet, ultimately into an ocean. But also basins with endorheic drainage, where all waters are collected in sinks or lakes not connected to other basins or the ocean. Core reference for assignment to an ocean is “Limits of Oceans and Seas” (IHO, 1953).

The “Major River Basins” and “Major River Networks” layers may be used in many ways: for example for visualization of basins or river networks in reports, or overlay with other GIS layers such as of groundwater basins or national borders, or for basin-related interpretations of model results.

Citation and acknowledgements of the “Major River Basins” and “Major River Networks” datasets should be made as follows: GRDC (2020): GRDC Major River Basins. Global Runoff Data Centre. 2nd, rev. ed. Koblenz: Federal Institute of Hydrology (BfG).

This service is published as an interactive web application by the Federal Institute of Hydrology (BfG) in Germany.

River Basin Layer

Major River Basins

Major River Network

Major Rivers

Basin

Continent

Ocean

Sea

Download selected basins

The download of selected basins contains the respective subset of the layers major river basins, major river layers and major river networks (upland area > 1575 km²)

Download complete dataset

The complete dataset contains the layers major river basins, major rivers and the major river network layers for all upland area sizes. Download size is 117 MB (ESRI Shapefiles) / 130 MB (GeoJSON)

Click on a basin to get a list of available runoff stations at GRDC. To access the data please use our GRDC Data Download/Download by Station, paste your station list in the Station Number field and follow the instructions for download

Introduction

Freshwater input into the world’s oceans is an important parameter in the global water balance. Rivers return water from land back to the ocean. Rivers carry materials, nutrients and pollutants from rural and urban areas and bring human impacts from land into the oceans. Large rivers in particular drain transboundary basins with competing interests and demands on the management of the shared resources. Against this background, drainage basins may be considered “major” in terms of basin size, water quantity and quality, but also in their hydro-political relevance or interest. In 2007, GRDC generated the first version of the Major Rivers Basins of the World dataset. Based on the flow direction dataset of HYDRO1k (USGS 2000), 405 basin polygons were derived. The river network of 687 associated river lines was generated in close collaboration with the German Federal Institute for Geosciences and Natural Resources (BGR) on the basis of their Major River Basins (BGR 2004) dataset.
With the HydroSHEDS (Hydrological data and maps based on Shuttle Elevation Derivatives at multiple Scales) mapping product a “suite of geo-referenced data sets in raster and vector format, including stream networks, watershed boundaries, drainage directions, and ancillary data layers such as flow accumulations, distances, and river topology information” (Lehner 2013) became available in a consistent format. HydroBASINS dataset provides a series of polygon layers of watershed boundaries and nested basin delineations following the Pfaffstetter coding principles. The HydroRIVERS dataset provides a global coverage of river reaches at high spatial resolution, each with a reference to the corresponding hydro-basin identifier. The HydroSHEDS database and more information are available at http://www.hydrosheds.org.
Seamless global coverage and 12 levels of sub-basin breakdown of HydroSHEDS offer the unique opportunity to base GRDC’s geospatial data products like the Major River Basins of the World datasets on a comprehensive and widely accepted data product. We used the HydroBASINS (WWF 2013) subset of polygon layers for a review of basin boundaries, and the HydroRIVERS subset (WWF 2019) of polylines to derive river networks associated to the basin polygons.

GRDC Major River Basins

The Major River Basins dataset is extracted from the HydroBASINS dataset using basic selection and generalization procedures. It is important to note, that GRDC has not re-assembled the river or lake basins or delineated new watershed boundaries. The basin polygons of edition 2007 were reviewed against the hybas-polygons of the HydroSHEDS dataset (online received in March 2018) and extended for 115 so-called WMO-Basins (GRDC 2020) which represent specific river basins. The Major River Basins polygons are generated from dissolving all hybas-polygons at the highest spatial resolution level (hybas_lev12) that intersect a basin polygon of the extended edition 2007, always inspecting the basin polygons at the next (coarser) generalization levels. In this way, basin polygons are generated to build up the new dataset of 520 major river basins. River basin polygons are attributed with: basin identifier, basin name and description, continent from which the water comes, sea and ocean into which the water flows, and an approximate of drainage area. Drainage area (in square km) is calculated by adding up the sub-area values specified in the hybas_lev12 datasets and does not reflect the real size of basin area. The calculated drainage area per basin ranges from 682 km² for the smallest basin (Coatan river basin, shared by Mexico and Guatemala) up to 6 Mio km² for the Amazon river basin. Overlaying basin boundaries with national borders, more than 250 of the 520 major river basins appear to be transboundary, more than 90 basins shared by 3 or more countries.

GRDC Major River Networks

The Major River Networks dataset is extracted from HydroSHEDS dataset using basic selection and generalization procedures. It is important to note, that GRDC has not re-assembled the river networks using a flow accumulation grid. The Major River Networks are generated from dissolving river-reaches of the HydroRIVERS dataset (online received in February 2020) that intersect the major river basin polygons. To allow for displaying a scalable network of streams for both the smallest river basin and a huge basin, a subset of hydrorivers_v10 reaches where the “upland area” exceeds the median of all upland area values of 35.59 km² is selected and split by deciles into ten subsets of hydro-river reaches. Layers of line sections are generated for each decile interval. At the highest level (above the 0.9 quantile) river networks for 475 (of 520) major river basins are displayed. In this way, river networks may be assigned to the 520 major river basins and further densified by activating river network slices:

Layer “mrb_rivnets_Q09_10” contains line sections representing an upland area above 7803 km².
Layer “mrb_rivnets_Q08_09” contains line sections representing an upland area between 1575 and 7803 km².
Layer “mrb_rivnets_Q07_08” contains line sections representing an upland area between 614 and 1575 km².
Layer “mrb_rivnets_Q06_07” contains line sections representing an upland area between 309 and 614 km².
Layer “mrb_rivnets_Q05_06” contains line sections representing an upland area between 181 and 309 km².
Layer “mrb_rivnets_Q04_05” contains line sections representing an upland area between 117 and 181 km².
Layer “mrb_rivnets_Q03_04” contains line sections representing an upland area between 82 and 117 km².
Layer “mrb_rivnets_Q02_03” contains line sections representing an upland area between 60 and 82 km².
Layer “mrb_rivnets_Q01_02” contains line sections representing an upland area between 45 and 60 km².
Layer “mrb_rivnets_Q00_01” contains line sections representing an upland area between 36 and 45 km².

River networks are attributed with properties of the associated basin: basin identifier, basin name and description, continent from which the water comes, sea and ocean into which the water flows, and an approximate of drainage area.

GRDC Major Rivers

GRDC Major Rivers dataset compiles “blue” lines of 983 named rivers which represent 520 major river basins. The river lines are selected from Major River Networks dataset and named using freely available datasets such as the “GeoNet Names” gazetter (https://geonames.nga.mil/namesgaz/). The river lines are attributed with: basin identifier, basin name, name of the river name which forms part of the river network.
The river lines of edition 2007 displayed 687 rivers associated with river basin polygons of edition 2007. Among other attributes, a long-term average discharge value along the river course is provided, calculated from generated mean discharge 1961-1990 as computed with WaterGAP 2.1 at a spatial resolution of 0.5 degree. The modelled river discharge values were grouped into ten classes and each river segment was assigned to a river class (category). Each class (category) represents an interval of discharge values in km³/year. The maximum (highest) assigned category along a river was picked to label the average discharge from the associated drainage basin at the river outlet.
An update of the calculated discharge using a new version of WaterGAP model is intended but not yet ready to update the river discharge attributes. For the time being, the river lines layer of edition 2007 with calculated discharge values is still valid and will be provided on request. Please note, that the river lines 2007 in some cases do not fit with river basin polygons 2020 which are updated using the HydroSHEDS dataset.

References

International Hydrographic Organization, IHO (1953): Limits of Oceans and Seas. International Hydrographic Organization, Special Publication No 23, 3rd Edition, IMP, Monégasque - Monte-Carlo, 45 pp. Online available at https://epic.awi.de/id/eprint/29772/1/IHO1953a.pdf

BGR (2004): Major River Basins. Federal Institute for Geosciences and Natural Resources, BGR. Hanover, Germany.

Lehner, B., Grill G. (2013): Global river hydrography and network routing: baseline data and new approaches to study the world’s large river systems. Hydrological Processes, 27(15): 2171–2186.

Lehner, B. (2013): HydroSHEDS technical documentation, version 1.2. World Wildlife Fund US, 1–25.

US Geological Survey (2000): HYDRO1k Elevation Derivative Database. USGS EROS Data Center, Sioux Falls, SD.

WWF (2013): HydroBasins, World Wildlife Fund. Data online available at www.hydrosheds.org. Online received in March 2018.

WWF (2019): HydroRivers, World Wildlife Fund. Data online available at www.hydrosheds.org. Online received in February 2020.

Acknowledgments

This product “Major River Basins of the World” incorporates data from the HydroSHEDS database which is © World Wildlife Fund, Inc. (2006-2013) and has been used herein under license. WWF has not evaluated the data as altered and incorporated within “Major River Basins of the World”, and therefore gives no warranty regarding its accuracy, completeness, currency or suitability for any particular purpose. Portions of the HydroSHEDS database incorporate data which are the intellectual property rights of © USGS (2006-2008), NASA (2000-2005), ESRI (1992-1998), CIAT (2004-2006), UNEP-WCMC (1993), WWF (2004), Commonwealth of Australia (2007), and Her Royal Majesty and the British Crown and are used under license. The HydroSHEDS database and more information are available at http://www.hydrosheds.org.

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