Irrigation & Drainage Systems Engineering

ISSN: 2168-9768

Open Access

Articles in press and Articles in process

    Research Article Pages: 18 - 8

    Technical Performance Evaluation of Selected Small Scale Irrigation Scheme in Arsi and Western Arsi Zone

    Bayan Ahimed* and Fekadu Gemeda

    In Ethiopia small scale irrigation schemes play a vital role in improving the livelihoods of the smallholder farmers’. However, existing small-scale irrigation schemes face various problems related to operation and maintenance, water management and sustainability. This study was conducted to technical performance evaluation of selected Small Scale Irrigation Scheme in Arsi and Western Arsi Zone using irrigation performance indicators. For this two scheme selected were Bubisa from Lemu-Bilbilo district of Arsi zone and Koma Arba from Adaba district of West Arsi Zone. From the study conducted on Bubisa and Koma Arba irrigation scheme using performance indices such as conveyance efficiency (Ec), application efficiency (Ea), on farm water lost (ROR+DPF), storage efficiency (Es), overall efficiency (Eo) and distribution uniformity (DU) and finally identifying problems of the scheme. For these study three farmers’ fields located at head, middle and tail of the two irrigation scheme were selected. From the result, parameters like Ec, Ea, on farm water lost (ROR+DPF), Es, DU and Eo were 67%, 60.27%, 39.73%, 89.59%, 90.50%and 39.77%, respectively for Bubisa irrigation scheme and 78%, 62.25%, 37.25%, 82.33%, 92.78% and 48.70% respectively for Bubisa irrigation scheme. Water Use efficiency (WUE) of Bubisa and Koma Arba scheme were 4.59 and 3.05kg/m3. This means that the yield from one meter cube of irrigation water for Bubisa irrigation scheme was higher than that of Koma Arba irrigation scheme. Sustainability of Irrigation System of the Bubisa and Koma Arba schemes were decreased by 42.7% and 62.5%compared with the planned. Therefore, for the improvement of the irrigation system management and the irrigation practice frequent performance evaluation is very important and solves problems related to operation and maintenance, water management and sustainability.

      Research Pages: 1 - 4

      Evaluations of crops coefficient crossponding to growth stage in semiarid climate zone, Arba Minch, Ethiopia

      Birara Gebeyhu*, Samuel Dagalo and Mekuanent Muluneh

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      Research Article Pages: 1 - 5

      Water Delivery Performance and Dependability of Irrigation Interval in Tendaho Sugar Estate, Ethiopia

      Eshetu Bekele*, Tena Alamirew

      Extensive effort and huge investment towards irrigation development is being made in Ethiopia. However, little or no attention is given to the monitoring and evaluation of the performance of already established irrigation systems. Consequently, many of the existing irrigation systems are deteriorating in their physical structures, operation and management. Hence, this study attempted to evaluate the performance of water delivery performance and dependability of irrigation interval in Tendaho sugar estate irrigation system in the lower Awash River Valley. Water delivered to canals was measured using flow measuring structure and duration of water delivery while actual irrigation interval was monitored for selected fields. The average values of Delivery Performance Ratio were resulted in 0.36, 0.53, 0.54 and 0.38 for main, primary, secondary and tertiary canals, respectively, and the average value of dependability of irrigation interval was resulted in 1.6 for selected fields. These results of both delivery performance ratios and dependability of irrigation interval reveal that reliability of water delivery during study time was rated under very poor, and the fields waited for long time to get irrigation water. To alleviate the problem and avoid water shortage during dry period, Gate of the Dam should be installed; off-taking canals head and cross regulators must be installed for all canals; regularly repair and calibration should be done for all existing regulators in the Sugar Estate.

        Research Article Pages: 1 - 8

        Determination of Irrigation Regime of Wheat using Cropwat in the Blue Nile Basin, Ethiopia

        Dires Tewabe*, Atklte Abebe, Amare Tsige, Alebachew Enyew, and Mulugeta Worku

        Population growth, high water competition (demand), and the effect of climate change have caused water shortage problems in the Nile basin. Therefore, improving water management and determine the water requirement of field crops is substantial. In this study, the Food and Agricultural Organization (FAO) CROPWAT 8.0 simulation model, local climate, and soil data were used to determine crop water requirement (CWR) and irrigation scheduling of wheat crop at Koga and Rib irrigation scheme. The CROPWAT Penman-Monteith and the United States Department of Agriculture (USDA) soil conservation service method were used to compute the reference evapotranspiration (ETo) and effective rainfall respectively. The result of the study showed that reference evapotranspiration was varied from 4.86 mm day-1 (maximum) to 3.14 mm day-1 (minimum) at Koga while at Rib it ranges from 4.67 mm day-1 (maximum) to 2.36 mm day-1 (minimum) during the study period. The effective rainfall was 156.5 mm at Koga and 160.5 mm at the Rib irrigation scheme. The irrigation requirement of wheat at Koga was 376.9 mm dec-1 while at Rib was 379.9 mm dec-1. The study showed that the CROPWAT model is an important tool to compute the crop water requirement of field crops in irrigated agriculture.

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