Performance  Evaluation  and  Sensitivity  Analysis  of  Fixed  and  Cutback  Flows  for  Furrow  Irrigation at Metahara Sugar Estate

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dc.contributor.author	Habib Dilsebo
dc.date.accessioned	2017-08-15T07:04:46Z
dc.date.available	2017-08-15T07:04:46Z
dc.date.issued	2004
dc.identifier.uri	http://hdl.handle.net/123456789/788
dc.description.sponsorship	Reports indicate that low efficiency is not inherent to the surface irrigation method and that application efficiency as high as 70 to 85 % can be achieved in this method under good design, operation and management systems (Merriam and Keller, 1978) . Thus, three independent but interrelated experiments were conducted to explore the possibilities of improving performance parameters of block ended furrow irrigation at Metahara sugar estate on the sugarcane crop. First part of the study deals with the performance evaluation of the existing �· ln this study the irrigators were free to exercise their conventlonei irrigati�n. Hence they decided the inflow�. and the inflow cutoff time a nd in effect the infiltrated dept�. However, the inflow rate, the advance, recession and cutoff times were measured during irrigation. The study resulted in application efficiency raging between 12-71 %, with 45% as -- the average. The second part of the study deals with the relative importance of furrow • length and �flow rat@ in affecting the irrigation performance parameter�. In /vthis study furrow lengths of 50 and 100 m with inflow rates of 2, 3, 4, and 5 l/s combinations were used as treatments to apply a gross depth of 1 �m water. The average application efficiency for 50 and 100 m.lonq furrows was 75%. Thus a 30% increment in application efficiency was obtained over the conventional practice through a careful adjustment of the inflow rate and The water I ost in the conventional practice is estimated to be 5 4 Mm3 per year as compared to the sensitivity experiment, which can produce 270, 000 ton of additional sugarcane at a water use efficiency of 5 kglm3. Moreover, the same excess water adds 9666 ton of salt per year increases the water table and also increases sediment concentration of reservoirs and canals. Excess water application a /so leaches down a large amount of agricultural chemicals that are applied to sugarcane. Hence, this inefficient irrigation has to be improved. From the experiments carried out, it was shown that the application efficiency can be improved considerably provided there is a good control over the inflow rate and the irrigation cutoff time. The uniformity of water application can also be improved through a proper siphon head adjustment. The third experiment was based on the cutback inflow rate. In this case an iriliiel inflow rate of 5 tis was supplied to all the furrows until the water front reached the furrow end. Thereafter, the inflow rate was reduced to 70 (i.e,3.5 tis), 60 (i.e. ,3 l/s), and 50% (i.e. ,2.5 tis) cutback ratios while in the last treatment the constant inflow rate of 5 tis was maintained until the end of irrigation. 134 mm depth of water was applied to all the treatments. Results of the study indicated that the maximum application efficiency was 78.5% at 50 % cutback ratio and the minimum was 78 % for fixed inflow of 5 tis. Therefore, cut back inflow with all its advantages and shortcomings brought no noticeable improvement in efficiency when compared to the sensitivity	en_US
dc.language.iso	en	en_US
dc.publisher	ARBAMINCH UNIVERSITY	en_US
dc.title	Performance Evaluation and Sensitivity Analysis of Fixed and Cutback Flows for Furrow Irrigation at Metahara Sugar Estate	en_US
dc.type	Thesis	en_US