Location: Water Management ResearchTitle: Growing more with less in the Westlands Water District in the San Joaquin Valley, California Author
|Ayars, James - Jim|
Submitted to: Ecological Herald of Uzbekistan
Publication Type: Review Article
Publication Acceptance Date: 5/10/2012
Publication Date: 9/1/2012
Citation: Ayars, J.E., Mirzaev, B. 2012. Growing more with less in the Westlands Water District in the San Joaquin Valley, California. Ecological Herald of Uzbekistan. p. 45-53. Interpretive Summary: The Westlands Water District (WWD) with 600,000 acres of irrigated land is a significant sector in California agriculture. Solving the problem of disposal of saline drainage water is required for it to remain sustainable. This manuscript discusses solutions for drainage water disposal developed as part of a five-year study conducted by the California Department of Water Resources and the US Bureau of Reclamation. It also highlights some of the challenges facing farmers to achieve sustainability in their operations. The solutions emphasized source control, drainage water reuse for supplemental irrigation, and land retirement. The concept of integrated on farm drainage management (IFDM), a system of successive reuse of drainage water on progressively more salt tolerant crops to reduce drainage volume was an outgrowth of this research. Source control, drainage water reuse, and land retirement have been extensively implemented within the Westlands Water District and IFDM has been implemented on limited basis. The impact of improved irrigation management, improved drainage water management, integrated on farm drainage management, and crop selection on water use efficiency are provided as examples for developing sustainable irrigated agriculture in Uzbekistan. Surface irrigation is the predominant method in Uzbekistan and as in the Westlands Water District. The cropping in the WWD is primarily field crops which is the case in Uzbekistan. In California there has been a gradual shift from surface irrigation to pressurized systems. This has been accomplished by a shift to higher value crops. It will be some time before this transition can be realized in Uzbekistan because of the State quotas on cropping of cotton and wheat.
Technical Abstract: Disposal of saline drainage water is a problem for irrigated agricultural throughout the world. In California the Westlands Water District in the San Joaquin Valley had its drainage service eliminated because of selenium contamination in the Kesterson Reservoir. A five-year study developed alternatives for drainage water disposal. The results from implementing these alternatives in the Westlands Water District provide a good model for consideration in Uzbekistan. The options developed included: source control, drainage water reuse, and land retirement. The concept of integrated on farm drainage management (IFDM) was developed as result of these studies. Source control is the reduction of deep percolation from irrigation by improving irrigation system design and management or changing to a more efficient system e.g. surface irrigation to sprinkler. Drainage water reuse is a practice that uses saline drainage water for supplemental irrigation on progressively more salt tolerant crops. Land retirement is designed to reduce total acreage particularly in those areas containing soils high in selenium. The IFDM concept integrates the practices of improved irrigation management with capturing and reusing saline drainage water for irrigation. IFDM has been demonstrated in several locations in California. The Westlands Water District and Uzbekistan have similar climates, water supply challenges, and cropping patterns. As a result, lessons learned in the WWD are applicable in the irrigated areas of Uzbekistan.