Seasonal behavior and spatial fluctuations of groundwater levels in long-term irrigated agriculture: the case of a sugar estate

This paper presents results on the spatial and temporal fluctuations of the groundwater table depth (GWTD) at Wonji-Shoa Sugar Estate (WSSE). Accordingly, spatial maps of GWTD were produced in a GIS (ArcView 3.3) environment from 35 groundwater monitoring piezometers. Results of the study revealed that WSSE, after nearly 60 years of irrigation, is experiencing a serious waterlogging problem. The groundwater (GW) depth is extremely shallow (<1 m below ground) in most of the piezometers throughout the entire season and showed great spatio-seasonal variability. The rate of annual increment of GW rise, coupled with seasonal fluctuation, has obvious repercussions and grave consequences for the sustainability of WSSE in particular and to the region in general. Unless the potential causes for the rise of GWTD are identified soon and feasible corrective measures for mitigating GW rise are introduced, severe crises in the region are inevitable.