Getahun, Sintayehu (2015) Assessment on Causes of Failure of Irrigation Canals and Its Remedial Measures: Case of Fentale Irrigation Project. Masters thesis, Addis Ababa University.
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Abstract
Like most developing countries, the economy of Ethiopia is highly dependent on Agriculture. Rain fed agriculture contributes by far the largest part of the economy and it is currently growing on average 5% per year. In Ethiopia 85% of the population is dependent on rain fed agriculture. In spite of being relatively rich in water and land resources, the country is unable to produce reliable food supplies due to highly uneven rainfall distribution and droughts. However, Ethiopia has an estimated 5.3million hectare of irrigable land, yet only about 200,000 hectare is presently irrigated and only provides approximately 3%of the country‟s food crop requirements. Similarly Oromia region regardless of its relatively better natural setting, most part of the region is suffering from food insecurity, particularly the low land area of the region, where majority of the population in the area were pastoralists. Oromia regional government has constructed different irrigation projects. However, most irrigation projects, including Fentale have failed to achieve the planed objectives due to various reasons. Therefore, this study is intended to assess the major causes for the hydraulic and hydrologic failures of Fentale irrigation project and to recommend possible solutions. Hydraulic and hydrologic failures of Fentale irrigation project were assessed by using primary and secondary data. Primary data were collected through field data measurement and observation. Secondary data were collected from designee document, other official documents and reports. Hydraulic failures were evaluated by manning‟s formula. The actual value of manning‟s roughness coefficient, discharge and velocity, were compared with the designed value. Moreover, hydrologic failure were evaluated by Soil Conservation Service (SCS) method. The findings revealed that the values of the calculated n for different sections on the main canal were between 0.039-0.072. However, the designed values range from 0.017-0.03 for the same canal on which n was calculated. The calculated velocities for different sections on the main canal were between 1.048- 0.62 m/s. The measured velocity range from 0.566-0.337 m/s for the same canal on which velocity was calculated. Similarly, the designed and measured discharge capacity within the canal stretch showed great difference. An increase on the values of the calculated manning‟s roughness coefficient (n) and the decrease in velocity and discharge causes the accumulation of silt along the canal. The findings related to hydrologic failure revealed that the values of design flood for cross drainages structure of 50 years recurrent intervals were between 6.07-51m3/sec and the calculated value of flood for cross drainages structure of 50 years recurrent intervals were between 22.44- 358.96m3/sec. Therefore, the other major causes for the damage of the irrigation structures and overtopping of the canals were as the result of the flood that came from catchment areas of the streams. Hydraulic performance of irrigation canal can be enhanced by appropriate design through use of adequate hydraulic parameters such as area, perimeter, velocity, discharge, and roughness coefficient and the hydrologic failure caused by underestimation of the cross drainage should be redesigned, constructed and maintained. However, maximum and efficient utilization of the Fenatle Irrigation Project can be achieved by not only on the major causes of failure, but also on examining the construction and management feature of the irrigation project in detail. Therefore, construction and management problems of Fentale irrigation project should be studied for efficient utilization.
| Item Type: | Thesis (Masters) |
|---|---|
| Uncontrolled Keywords: | Hydrologic Failure, Hydraulic Failure. Fentale Irrigation Awash River Basin |
| Subjects: | G Geography. Anthropology. Recreation > GE Environmental Sciences S Agriculture > S Agriculture (General) T Technology > TA Engineering (General). Civil engineering (General) T Technology > TC Hydraulic engineering. Ocean engineering T Technology > TD Environmental technology. Sanitary engineering |
| Divisions: | Africana |
| Depositing User: | Andriamparany Edilbert RANOARIVONY |
| Date Deposited: | 27 Nov 2018 11:17 |
| Last Modified: | 27 Nov 2018 11:17 |
| URI: | http://thesisbank.jhia.ac.ke/id/eprint/7793 |
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