Identifying the potential causes of waterlogging in irrigated agriculture: The case of the wonji-shoa sugar cane plantation (Ethiopia)

The Wonji-Shoa Sugar Estate (WSSE) has been producing sugar for about 60 years and is currently affected by a chronic waterlogging problem (about 90% of the plantation area is affected by critical waterlogging). Hence, the current study investigated the potential causes of the rise of groundwater table depth (GWTD) at the WSSE in an integrated and comprehensive manner. The study revealed that the shallow water table at the WSSE is due to one and/or a combination of the different factors responsible for the rise of GWTD: rainfall, surface runoff, irrigation, drainage, soil condition (clay), topography, flooding, seepage losses, land use/cover change, and a subsurface contribution from the Awash River. However, direct rainfall, incoming surface runoff, flat topography, soil property (clay), poor drainage (natural and artificial) facilities and uncontrolled irrigation water management are mostly responsible for the rise and fluctuation of GWTD in the area. Finally, the finding emphasized the need to develop corrective measures urgently.