Engenharia de Sistemas de Irrigação e Drenagem

Estimation of Seepage Loss in Irrigation Canals of Tendaho Sugar Estate, Ethiopia

Abstract

Eshetu BD and Alamirew T

Open canals are the common method used to convey water for irrigation in Ethiopian sugar estate, however, little or no attention is given to the evaluation of conveyance systems. Consequently, many of the existing conveyance systems are deteriorating in their physical structures, operation and management. Due to this the current study was conducted to quantify the amount of seepage loss through lined and unlined irrigation canals of Tendaho sugar estate. Seepage losses were determined by inflow-out flow method for primary, secondary, and tertiary canals, while water velocity was determined using a current-meter. The average seepage losses were resulted in 0.55% per 100 m (0.0126 lit/s/m²) and 0.84% per 100 m (0.0180 lit/s/m²) for lined and unlined primary canals whereas, 3.65% per 100 m (0.0391 lit/s/m²) and 4.27% per 100 m (0.0248 lit/s/m²) were obtained for secondary and tertiary canals, respectively. In the result, primary canal seepage loss was higher in unlined than in lined by 0.0054 lit/s/m² of wetted area of the canal. The result reveals that high seepage loss for both lined and unlined canals may be attributed through damage of geomembrane lining and poor maintenance of earthen canals. To minimize excess seepage and improve the conveyance system, overall maintenance and repair of canals should be done in the Estate.