Irrigation / Regadío
Worldwide 70 percent of the fresh water from rivers, lakes, and aquifers, is used to irrigate one-fifth of the world’s crops in order to produce 40 percent of the world’s food1. Water waste is a large problem, as only 60 percent of the water that is used for irrigation is delivered to the target crops1.

The Oregon Water Resource Department estimates that nearly 646 million gallons of water per day will be needed for Willamette Valley agriculture in 20102. Estimates for the use of water in Oregon are higher than the national average, as nearly 78 percent of the water in the state is for irrigation compared to 40 percent for the US3. In Oregon, irrigation efficiency estimates for all crops except for grapes and livestock range from 52-76 percent; grapes fall at 90 percent and livestock is at 100 percent2. In the Willamette Valley watershed efforts are underway to conserve water but the only agriculture modification is an update of distribution systems4.

Different methods of irrigation are more efficient than others. Flood irrigation typically loses 40 percent of water through evaporation, seepage, and runoff1. Center-pivot forms of irrigation are more efficient, as they allow approximately 89 percent of the water to reach crops through low-pressure sprinklers while the precision applicator form of center-pivot irrigation allows approximately 90-95 percent of water to reach the crops1. Drip irrigation and micro-irrigation systems are the most efficient, as they prevent evaporation and allow the water to reach the roots more directly1.

Irrigation / Regadío Translation Needed

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1. Miller, T.G. (2007) Living in the Environment, Fifteenth Edition (Canada: Thompson).
2. Oregon Water Resources Department (2009) OWSCI Water Demand Forecast Model. Available at (accessed July 2009).
3. Oregon Agriculture in the Classroom Foundation (no date) A Look at Oregon Agriculture. Available at / (accessed June 2009).
4. Oregon Water Resources Department (no date) Conservation Project Search, Willamette Basin. Available at (accessed July 2009).

Related Information

Oregon Department of Agriculture: Education and Outreach Library, Irrigation
Oregon Department of Agriculture: Irrigation Efficiency and Water Management
Oregon Water Resources Department: Conservation and Supply Resources Program
Oregon Water Resource Congress
Oregon Water Resources Department: Oregon Water Supply and Conservation
Tualatin Valley Irrigation District

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