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Designing a supplemental irrigation system




Samani, Zohrab A., author
Hargreaves, George H., author
U.S. Committee on Irrigation and Drainage, publisher

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In the dry season when the rainfall contribution to crop water requirement is not significant, the amount of land to be irrigated for maximum profit with a limited supply of water, can be easily calculated. However, in the rainy season when rainfall contributes a significant amount of the crop water requirement, the amount of land which can be irrigated by a supplemental irrigation system varies due to spatial variability of rainfall. In designing a supplemental irrigation system the long term variability of rainfall as well as economical parameters should be taken into account. This paper describes a methodology for designing a supplemental irrigation system and for calculating the optimum amount of land which should be irrigated with a limited supply of water. The optimum amount of land to be irrigated is calculated for one station in EI Salvador using crop yield models, long-term climatological data and economical parameters. since the day to day climatological data are not often available in many countries, the paper describes how a climatological data-base together with a weather generating model can be used to design a supplemental irrigation system.


Presented at Planning for water shortages: water reallocations and transfers drought management: proceedings from the 1989 regional meetings held on August 24-25, 1989 in Boise, Idaho and on October 19-21, 1989 in St. Louis, Missouri.

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