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ARS Home » Research » Publications at this Location » Publication #94718
Title: OPERATION OF CONTROLLED-DRAINAGE AND SUBIRRIGATION FACILITIES FOR WATER TABLE MANAGEMENT

Author
item Fouss, James
item EVANS, ROBERT - NC STATE UNIV., RALEIGH
item THOMAS, DANIEL - UNIV OF GA, TIFTON
item BELCHER, HAROLD - MI STATE UNIV., LANSING

Submitted to: American Society of Agronomy Monograph Series
Publication Type: Book / Chapter
Publication Acceptance Date: 7/10/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: Manual and automated methods of operation have been developed for dual-purpose controlled-drainage and subirrigation systems to manage water table depth in humid climate areas. Much research and development has focused on the integration of water table management with the application of agrochemicals (fertilizers and pesticides). The successful integrated management of water table control (WTC) systems and agrochemical application practices has two goals: (1) Achieving near optimum crop production potential and efficiency, and (2) obtaining maximum water quality benefits by reducing off-site impacts caused by sediment and agrochemical losses in runoff and subsurface drainage. Guidelines are presented for selecting the method of control and settings for operational parameters of a WTC system with given layout and drainage outlet conditions. Guidelines may be based on prior experience, research results, or long-term simulations with various computer predictive models. The in-field performance of a fully automated control of the drainage outlet water level (in an outlet sump-structure) is discussed and illustrated, such as adjustment or regulation of the drainage outlet water level that is based on a feedback signal of the water table depth electronically monitored at the midpoint between drainlines.

Technical Abstract: Manual and automated methods of operation have been developed for dual-purpose subsurface conduit controlled-drainage and subirrigation systems to manage water table depth (WTD) in humid climate areas. Much research has focused on the integration of water table management with the application of agrochemicals (fertilizers and pesticides) to accomplish two major goals: (1) Achieving near optimum crop production potential and efficiency, and (2) obtaining maximum water quality benefits by reducing off site impacts caused by sediment and agrochemical losses in runoff and subsurface drainage. Technical guidelines are presented for selecting the control and operational parameters of a water table control (WTC) system with given layout and drainage outlet conditions. The in-field performance of an automated sump controlled drainage outlet water level is illustrated by 1996 field experimental results, when rainfall received was about 90% of normal. Automated control of outlet water level at an average depth of 0.75 +/ 0.10 m maintained a field WTD of 0.78 +/- 0.11 m at the midway between drains spaced at 15 m. After rainfall the automated system typically returned the WTD to the desired 0.75 m depth in less than 24 hrs. Operation of WTC systems with an open ditch outlet and an adjustable overflow weir is also discussed.