Effect of Agricultural Drainage on Water Quality in the Humid Portion of the Pacific Northwest

Backlund, Virgil L.; Ross, Elwin A.; Willey, Patrick H.; Spofford, Thomas L.; Renner, Dean M.; ,

Effect of Agricultural Drainage on Water Quality in the Humid Portion of the Pacific Northwest

by Virgil L. Backlund, West Natl Technical Cent, Portland, United States,
Elwin A. Ross, West Natl Technical Cent, Portland, United States,
Patrick H. Willey, West Natl Technical Cent, Portland, United States,
Thomas L. Spofford, West Natl Technical Cent, Portland, United States,
Dean M. Renner, West Natl Technical Cent, Portland, United States,

Document Type: Proceeding Paper

Part of: Management of Irrigation and Drainage Systems: Integrated Perspectives

Abstract:

Agricultural drainage first began in Washington around 1830 and in Oregon around 1840. The first efforts to drain soils for agricultural use began by constructing shallow ditches spaced 18 - 20 meters apart to remove excess surface waters from croplands. Farming of poorly drained soils way by these systems of beds until the 1930's. These beds interfered with the use of modern machinery and in the 1930's the establishment of beds was diminishing in favor of subsurface tile systems. Between 1930 and 1980 there was a substantial increase in subsurface tile drainage activity which peaked during the 1960's. Since 1985, installations of subsurface and surface drainage have gradually diminished and construction of drainage systems has been limited to replacement of existing failed or deteriorated systems. By reducing saturated soil conditions through subsurface drainage, surface water quality has benefitted by reductions of nutrients and pesticides associated with surface runoff. With the increase of animal waste applications to fields, additional research is needed to quantify the impacts of subsurface drainage on ground and surface water quality.

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