Senior Civil/Structural Engineer - Barrages/Dams/Canals - International

Position: Senior Civil/Structural Engineer - Barrages/Dams/Canals - International

Qualification and Experience: The Civil/Structural Engineer shall have at least a master’s degree in Civil Engineering and have a minimum of fifteen years of professional experience. A minimum of five years of that experience should have been acquired on structural design of large hydraulic structures on major rivers.

Project Background

The Government of Sindh (GoSindh) has received a credit from the International Development Association to finance the Sindh Barrages Improvement Project (SBIP). The project aims to strengthen the Sindh Irrigation Department’s capacity to operate and manage barrages and improve the reliability and safety of Guddu and Sukkur Barrages. The Project also supports the transition to managing the three barrages (Kotri, Sukkur and Guddu) as one integrated system in terms of water allocation, sediment management, and maintenance.

Under SBIP, the Sindh Irrigation Department is seeking International Consultant for Technical Assistance for the Rehabilitation of Kotri Barrage. This consultancy will include diagnostic studies of Kotri Barrage, design of interventions, and support to their implementation. The consultancy will also help formulate improved Standard Operational Procedures (SOP) and will prepare a Rehabilitation and Upgradation Project for this Barrage.

Kotri Barrage

Kotri Barrage is located downstream of Guddu and Sukkur Barrages which is the last hydraulic structure on the Indus River. Formally known as, Ghulam Muhammad Barrage which is adjacent to Hyderabad city and 120 km northeast of Karachi. It was constructed and commissioned on the Indus River in 1955 primarily to irrigate 1.2 million hectares of land in lower southern Sindh. The barrage is 915 meters (m) long with 44 bays, and it incorporates a road bridge, a navigation lock for river traffic, and two fish ladders. The design flood passing capacity of the barrage is 875,000 c.f.s (24,777.24 c.m.s). The highest passing flood volume recorded was 981,000 c.f.s in 1956, and the second highest was 939,000 cusecs in 2010 respectively. Four main canals, namely Kalri Baghar Feeder Canal on the right bank, Akram Wah, New Fulelli, and Pinyari (old Fulelli) on the left bank offtake from the barrage and are the main source for supplying water not only for agriculture but also for drinking and industrial water supply for Karachi including of Kotri, Jamshoro, and Nooriabad through KB Feeder; Hyderabad through Fulelli Canal; and several small cities and rural areas through tertiary canals. During the last two decades, the demand for municipal supplies has increased substantially due to population growth. The GoPakistan and GoSindh are also working to increase supplies to Karachi through the K-IV project from Keenjhar Lake. This increased abstraction from the lake will also require additional supplies from Kotri Barrage. Studies indicate that rehabilitation of the Kalgri Baghar Feeder Upper Canal could convey sufficient additional water for K-IV Phase 1. However, supplying water for the subsequent two phases of K-IV would require additional carrying capacity to convey water from Kotri Barrage to Keenjhar Lake.

Since its commissioning in 1955, the barrage performed exceptionally well until the early eighties, when the authorities reported problems in operational procedures, including corrosion of gates. After a diagnostic study, the Irrigation Department implemented a rehabilitation project completed in 2000. The gates of the main barrage and off-taking canals were replaced. The civil works included curing voids in downstream pavement filled through grouting and underwater concreting, the road bridge slab replacement, and motorization of the gate hoisting mechanism, including electrification. As the last controlling structure on the Indus River, the barrage also releases environmental flows to the Indus Delta. The flow data of the previous two to three decades show a decline in the environmental flows, causing severe environmental degradation in deltaic areas.

Recently, operational managers of Kotri Barrage have reported sedimentation along the right bank of the upstream side, which is impacting the main river flow, changing it to an oblique angle towards the left pocket. The sediment accumulation is also reducing the capacity of the barrage pond. The barrage team has also identified a pit formation near the left pocket divide wall. This requires detailed investigations underneath the pavements and a modeling study to align flows into the barrage and remove sediment.

The off-taking canals are also facing problems, particularly in the left bank. The operation is the combined channel of the Fulelli and Pinyari canals makes it challenging to maintain the required water levels independently in both canals. The problem may require interventions like bifurcating the combined channel into two independent canals or changing the way flows are controlled at the head and tail of the combined channel.

The preliminary investigations by the Irrigation Department indicate that the barrage needs some serious interventions, including the following: i) rehabilitation of Electro-Mechanical and Civil Components, (ii) Sediment Management, (iii) securing Maximum Flood Passing Capacity and Flood Routing, (iv) Refurbishing and Improving the Barrage Monitoring Instrumentation for long-term safety of assets, and (v) Improving the delivery of design flows as per schedule to the four canals.