Interaction of Irrigation Water and Drainage Flow

Ayars, James E.; Schoneman, Richard A.; ,

Interaction of Irrigation Water and Drainage Flow

by James E. Ayars, USDA/ARS, Fresno, United States,
Richard A. Schoneman, USDA/ARS, Fresno, United States,

Document Type: Proceeding Paper

Part of: Structures for Enhanced Safety and Physical Security

Abstract:

This study was conducted to evaluate the effect of irrigation management on subsurface drainage flow in an arid irrigated area. The irrigation management and drainage flow were monitored from four fields in a 14000 ha irrigation district located on the west side of the San Joaquin Valley. Furrow irrigation was the predominate method used on the fields with some sprinkler irrigation being used for germination of crops. The irrigation application efficiency was poorest during the pre-plant and first seasonal irrigation. The peak flows from the drains occurred during the winter and early spring, which corresponded to the timing of the aforementioned irrigations. There was considerable variation in both the peak and total drainage flow which could not be explained as differences in deep percolation. At some sites there was probably a significant amount of deep percolation going past the drains while in one case the drains were probably intercepting water originating from outside of the field. The drainage rate data show that the rate decreases with time during the irrigation season. These data show that the current methods to estimate deep percolation under irrigation for purposes of drainage design are inadequate.

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