Why should planners include drainage in irrigation reclamation projects?

Planners must include drainage in irrigation reclamation projects primarily to prevent the accumulation of salt in the soil, which can inhibit plant growth and lead to project failure.12

Because all irrigation water contains some level of dissolved salts, these minerals remain in the soil as water evaporates or is transpired by plants. Without adequate drainage to allow water to move downward through the soil profile and flush these salts away, they accumulate to levels that damage crops and degrade soil structure.23

Furthermore, drainage is essential for managing water tables. By installing subsurface drainage systems, planners can lower high water tables, which prevents the upward movement of saline groundwater that would otherwise deposit additional salts at the surface. In many cases, a combination of irrigation and drainage is the only effective way to reclaim lands that have already been abandoned due to severe salt accumulation. Consequently, drainage is considered a companion requirement for the long-term sustainability of irrigated agricultural lands.324