Water characteristic curves and water status indicator

This paper attempts to introduce specific analytical meanings for the frequently used terms “water stress” (Falkenmark 1992 Falkenmark, M. and Widstrand, C. 1992. Population and water resources: a delicate balance. Population Bulletin, 47(3): 1–36. PubMed] , Google Scholar], Vorosmarty et al. 2000 Vorosmarty, C. J. 2000. Global water resources: vulnerability from climate change and population growth. Science, 289: 284–288. Crossref], PubMed], Web of Science ®] , Google Scholar], 2005 Vorosmarty, C. J. 2005. Geospatial indicators of emerging water stress: an application to Africa. AMBIO, 34(3): 230–236. Crossref], PubMed], Web of Science ®] , Google Scholar]) and “water strain” (Haddadin 2007 Haddadin, M. J. 2007. Quantification and significance of shadow water in semi arid countries. Water Policy, 9: 435–456. Crossref], Web of Science ®] , Google Scholar]) by drawing an analogy from the science of engineering mechanics. It introduces “water characteristic curves” and a “water modulus” that defines the status of indigenous water of a given country. Compared to other tools that have been introduced to reflect the “water footprint” of a country (Hoekstra and Chapagain 2008 Hoekstra, A. Y. and Chapagain, A. K. 2008. Globalization of water: sharing the planet's freshwater resources, Oxford, UK: Blackwell, 53–65, Chapter 6.  Google Scholar]), the water modulus is different in approach and meaning and is more reflective of the adequacy of indigenous water resources of countries.