Charting a Course – Agriculture
In 2005, water used for agriculture accounted for 5% of national intake. Included in agriculture are two subsectors: crop and animal production. Agricultural water use is primarily for irrigation (84%) and livestock watering (14%). In contrast to the industrial sectors, much of the water use in agriculture is considered consumptive due to evaporation, transpiration, and loss to groundwater; therefore only one-quarter of the intake water is returned to its source. Water intake in agriculture steadily increased by about 50% from 1981 to 2001, but then decreased substantially from 2001 to 2005 by 57%, resulting in about 38% below 1981 levels.
The value of agricultural production rose steadily from $24.5 billion in 1981 to $38.6 billion in 2005. This, in combination with the significant drop in water intake between 2001 and 2005, had the effect of driving down water-use intensity by 60% between 1981 and 2005, with the most notable decrease occurring since 2001.
Despite being equal in the value of output to animal production historically, crop production used 95% of the water in the agriculture sector. From 1981 to 2001, water use and economic growth increased proportionally causing the water intensity of the crop production sector to remain relatively stable. However, in 2005, water use in crop production dropped to one-third of what it was reported to be in 2001. This drop in water use per unit of output was likely caused by a large decrease in the amount of water needed for crop irrigation due to higher precipitation that year. This reduction in water intake in 2005 caused the water intensity to drop by 70% of its 1981 value.
It is difficult to explain improvements to water intensity in agriculture. However, case studies of the Okanagan Valley in British Columbia, where water intensities have improved significantly, suggest possible reasons: weather and climatic conditions, adoption of newer technologies and best management practices, a change to more drought-resistance crops (less water intensive), and decommissioning of previously irrigated lands.
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