November 2013: The Global Water Forum (GWF) has proposed defining river basins into eight cross-continent ‘hydrobelts’ in a discussion paper titled ‘Global Hydobelts: A new method to define the world’s river basins.’ According to the paper, this delineation will facilitate reporting of water resources and analysis of world river basins, particularly for global change and earth system science research.

The authors, Michel Meybeck, Matti Kummu and Hans Dürr, identified eight hydrobelt regions using three criteria: natural hydrological basin boundaries; river basin hydro-climates, such as average annual air temperature and annual water runoff; and continental boundaries. The eight hydobelts are the: boreal belt; North and South Mid-Latitude belts; North and South Dry belts; North and South Sub-tropical belts; and Equatorial belt. The hydrobelts have symmetrical hydroclimates, with a few differences between North and South belts.

The hydrobelt approach will assist in global climate change assessments, including on aquatic biodiversity, carbon and silica cycles and river geochemistry, according to the authors. They anticipate applying this approach to inform water governance and state their intention to create a population-focused water security indicator based on hydrobelts.

The paper describes the characteristics of each hydrobelt, including lines of latitude and longitude, temperature ranges and water runoff levels and sources, and presents maps, charts and tables elaborating on the hydrobelts. It also explains the limitations of units typically used to conduct global water assessments, arguing continent, political region or country scales are not well suited for global change research, do not support integrated analysis of water-related issues at the river basin level and mask water disparities among countries and continents. Similarly, given the more than 8,000 river basins around the world, conducting assessments at this level is not practical. [GWF Press Release] [Publication: Global Hydobelts: A New Method to Define the World’s River Basins]