The site is relatively flat with a surface slope of less than 1 percent. The site has a high natural water table or shallow impermeable layer within 10 to 25 feet of surface. The site has a good drainage outlet at least 3 feet lower than the average land surface. An adequate water supply is available. Schematic of a subirrigation system.
Water is pumped into the outlet ditch then moves through the underground tubing due to gravity flow.
Water moves from the water table into the root zone by capillary flow. Field sites should be evaluated before setting up any water management system. The actual design and sizing of a specific system can also be evaluated. The model evaluation considers such factors as crop, site and soil characteristics, and weather conditions, all of which are important when selecting and sizing a specific system. The model user can then recommend the best water management alternative based on optimizing long-term simulated yields.