ASSESSMENT OF WATER LOGGING PROBLEM AND DETERMINATION OF DRAINAGE PARAMETERS FOR THE DESIGN OF DRAINAGE SYSTEM AT WONJI-SHOA SUGAR ESTATE

Abstract

This research assesses the water logging problem and suggests the suitable method of drainage system for the selected fields at Wonji-Shoa sugar estate which is the oldest irrigation project in Ethiopia. The study was conducted on some part of highly water logged fields of the farm which was identified by the analysis of seven years ground water data collected from Ethiopian Sugar Development Agency Research Directorate. The EC, SAR, pH and other soluble anions of soil and water samples were observed to be in the normal range except the EC value for the ground water sample which is approaching to the marginal EC value. The computed surface drainage coefficient indicated that surface drainage system was not suitable solution to combat the observed water logging problem and salinity level control- in the selected fields. Therefore, pipe drainage system with pipe radius of 10cm at 2.0m drain depth is expected to be the most suitable combination for the selected fields.