|Molden, David - INT WTR MGT INS SRI LANKA|
Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 12, 2005
Publication Date: March 5, 2007
Citation: Clemmens, A.J., Molden, D.J. 2007. Water uses and productivity of irrigation systems. Irrigation Science. 25:(3)247-261 Interpretive Summary: Worldwide, the performance of irrigation projects is often below original expectations. Water resources in many part of the world are increasingly in short supply. There is a continuing need to maintain or increase food supplies while less water is available for irrigation. This eventually will require irrigated agriculture to substantially improve its ability to produce food and fiber with limited supplies. These conditions suggest the need to substantially improve the productivity of agricultural water supplies. In this paper, it is hypothesized that the water productivity of an irrigation project is related to the uniformity of irrigation and the ability of water distribution systems to reliably and equitably supply water to users. Examples are given where productivity is related to a combination of water delivery service and relative water supply. These results should be of use to consultants, the World Bank, the Bureau of Reclamation, and other government agencies.
Technical Abstract: Reducing overall water diversions for agriculture, while maintaining or increasing production to keep up with increasing world population, has been and will continue to be a challenge. Yet there is not good agreement regarding the programs needed to improve the productivity of agricultural water use, nor what increases are feasible. It is recognized that field irrigation is inherently nonuniform. So also is the distribution of water to users and water delivery service nonuniform. Here, we suggest that crop-scale irrigation uniformity can be examined at a project scale by understanding how field, farm and project irrigation systems contribute to nonuniformity. We also discuss the interrelation between project scale uniformity and the relative irrigation water supply, and their combined impact on project productivity. We provide an example which relates internal measures of project performance (e.g., water distribution operations) and external measures of project performance (e.g. project-wise water productivity).