PRE-FEASIBILITY STUDY OF BHUTENI IRRIGATION PROJECT

Abstract

An irrigation system is used to artificially supply water to agricultural land to support plant growth and crop production. Bhuteni irrigation project, a medium sized irrigation project, is selected for the prefeasibility study. There is abundance of land for crop production but due to ineffective irrigation system only a single crop at some area is cultivated. This project aims to explore possibility to increase the command area with three types of crops throughout the year.

Metrological database for the present study was obtained from Department of Hydrology and Meteorology for analyzing flood and monthly flows. Discharge measured was used to calculate the monthly flows using MIP method and these data were used to calculate irrigation water requirement. The structures were designed to meet the requirement.

Bhuteni irrigation project is a medium sized irrigation project located at Goldhap of Jhapa District. Its catchment area at the diversion point is 25.8 km2. The maximum discharge of river is 6.7 m 3 /s in August. As per requirement for command area of 750 ha, the maximum

required canal discharge is 1.91 m3

/s. The project will have a weir with gated system to pond the level of 1.4m for irrigation. The frontal type of intake is designed to supply water to the canal. For small discharge, triangular canal with round bottom is designed. Settling basin is designed to remove the silt from canal. Sarda fall type drop is designed where there is abrupt change in bed level throughout the canal as per requirement. Cross regulator and head regulator are designed to regulate flow at diversion points. Culvert is designed where a pathway intersects with the canal alignment. The headwork structure can pass flood discharge of 131 m3

/s for 100 years return period safely. About 10% of water will be discharged on downstream through under sluice for water right safety. Every attempt has been made to consider almost all the parts and get most reliable data. Due to time constraint Environmental Impact Assessment has not been done. The total estimated cost of the project is 163.21 million Nepalese Rupees and the net revenue generate from the irrigation system is 72.43 million Nepalese Rupees per year. The annual revenue generated in 20 year time period gives total revenue. The B/C ratio obtained is 2.84. Thus project is feasible.