Head-works Construction of Sikta Irrigation Project

Project Description

The main objective of this Service is to provide technical backstopping to the project management in the headworks construction carried out under the ICB Contracts (two civil works contracts of US$ 25,768,186 for Headworks construction and US$ 25,000,000 for main canal construction). The project is being developed to provide irrigation water to the project net command area of about 34,500 ha on its right bank and 12,600 ha on the left bank in Banke district (Terai area). The left side canal system has also integrated two existing farmers managed irrigation schemes, namely Rajkulo and Fettehpur, in its planned irrigation area. The total estimated project cost US$ 50.76 million.

Assignment Description

Detailed review, revisit and modification of design (hydraulic and structural) works of the intake (headworks) and associated structures, as necessary, of: • RCC raft barrage (317 m in length) with a single land RC road bridge across the West Rapti River. • Head regulator of 62.5 m3/s on the right bank • Head regulator of 2.5 m3/s on the left bank and modification of the structure with 14.7 m3/s intake capacity • A 610 m long settling basin (62.5 m3/s) in the Sikta Feeder Canal • 1, 440 m long sediment flushing canal with a capacity of 62.5 m3/s • Guide and marginal bunds for river protection works • Five numbers of RCC barrel type CD works • Prepared the design drawings and issued to the International Contractor, SINO-HYDRO Corporation, P. R. of China • Layout of the Carried out design revisit of the settling basin in the Sikta Main Canal • Assisted the Project in project and contract management of two ICB contracts – Headworks Construction with the contract sum of NPR 1.85 billion (equivalent US$ 25.77 million), and main canal (15.0 km portion with 50m3/s canal capacity) construction (equivalent US$ 25,000,000), and three NCB contracts for main canal (3.0 km) • Layout of the headworks and other project structures, and main canal portions • Construction supervision and quality control of the construction materials and works that consisted embankment works of 1.36x106 m3, concrete works of 169,150 m3, reinforcement steel of 8,000 MT and gabion works of 53,000 m3. • Planning of electro-mechanical control buildings for gate operation • Carried out design of vertical steel gates and lifting arrangements (stop logs, hoisting, operation decks, etc.) and control room for the barrage that consists of 5 nos. of undersluice gates – each size of 10m x 5.5 m (3 nos. on the right and 2 nos. on the left) and 13 nos. of spillway gates – each size of 17m x 4m, equivalent to 1,880 MT of steel works. • Completed the following studies, investigation and design works: • Hydrological study of the West Rapti River Basin that included Rainfall-Runoff Modeling and flood frequency analysis at the Sikta Headworks site • Hydrological study of 13 ungaged river crossing the Sikta Main Canal between Ch. 0+000 km and Ch. 15+000 km • River cross section survey, river modeling of the West Rapti using HEC-RAS software and design of river training works near Sikta and Aghaiya villages, in the upstream of the headwork site • Geological/Geo-technical study in the headworks area and Sikta main canal upto chainage 15+000 km • Collection, database management and analysis of rainfall data of Bijuwatar station at Pyuthan district, Ghorahi station at Dang district and Libang station at Rolpa district in the West Rapti River basin. • Collection, data management and analysis of river sediment at the intake site of the West Rapti River • Supervision and contract management during the defect liability period • Preparation Operation & Maintenance Manual • Prepared periodic (monthly and annual) reports and Project Completion Report.