Improved indicators of water use performance and productivity for sustainable water conservation and saving

Water use concepts and performance descriptors that may be useful in defining conservation and saving of water are discussed with the aim of improving the overall performance and productivity of water use. New indicators are proposed which include consideration of water reuse and aim to assist in identifying and providing clear distinctions between beneficial and non-beneficial water uses. An analysis of productivity concepts useful both in irrigation and elsewhere is provided together with suggestions for where commonly used terms, such as the broadly used “water use efficiency” among others, would be better avoided in irrigation engineering and given much more narrowly defined meanings in agronomy and biological sciences. Particular attention is given to economic issues in water productivity. The analysis is completed with various case study applications at irrigation farm and system scales. It is recommended that a set of terms (not necessarily those developed here) be widely adopted that will provide a basis for easy, certain communication and provide widespread common understanding of the issues which must be faced to develop approaches to achieve efficient water use.