Detailed Feasibility Study of Nepal Gandak Irrigation System Extension Project

Project Description

The Nepal Gandak West Canal Irrigation System (NGWCIS) was constructed under an agreement between India and Nepal to use the water of the Narayani River under the Gandak treaty. As per the treaty, the government of India was to construct ‘the Western Nepal canal including the distributary systems thereof down to a minimum discharge of 20 cusecs (566 lps) for providing flow irrigation in command area estimated to be at 40,000 acres (16,187 ha).
The command area is 8,700 hectares and covers 19 former Village Development Committees. The main canal has a length of 32 km and a discharge capacity of 8.5 m3/s, while branch and minor canals have various discharge capacities with a minimum of 566 lps.
The main objective of the consulting services is to provide detailed feasibility study for engineering survey, planning and engineering design, preparation of drawings and cost-estimate of the Gandak Extension and Narsahi Branch canal networks to water-course level, considering economic and technical viabilities. The estimated project cost is NPR 3,315,847,000.00

Assignment Description

Carried out detailed topographic survey of 7,500 ha Gross Command Area (6,466 ha in Gandak Extension Canal and 1,560 ha in of Narsahi Branch Canal) including the command area survey, canal alignment/profile and cross-section survey, work-inventory along the canal alignment, structure site survey, survey for drainage development, and survey for cross-drainage and flood protection works. • Conducted necessary survey/studies for the identification of possible measures of sediment control and designed a desilting basin of size 500 mx36 m • Conducted necessary hydro-meteorological data collection and analysis to assess crop-water requirement, and for the determination of design flood discharge of the drain crossings. • Conducted geological and geomorphological data collection and analysis as required. • Conducted necessary agricultural data collection and analysis as required. • Conducted detailed engineering design of Gandak Extension Main Canal (6.0 m3/s capacity, 25.8 km long and 12 m lift), Narsahi Branch Canal (1.6 m3/s capacity, 6.1 km long) including 103 major hydraulic structures (canal syphons, LD Syphons, Escapes, Regulators, Culvers, etc.), and Gravelled road of overall length aggregating to 53 km. • Carried out detail engineering design (hydraulic and structural) and preparation of detailed drawings, and quantity and cost estimates (Bill of Quantities) of the canal network and associated structures • Prepared the Detailed Feasibility Study Report • Proposed project implementation schedule, with necessary recommendations.