Sediments monitoring at barrage and canal levels needed to remove: Francois

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By Rehan Khan Khushik

KARACHI : World Bank Task Team leader Mr Francois Onimous has emphasized on establishment of a barrage management unit which will work on repair, maintenance and operation of Guddu, Sukkur and Kotri barrages and monitoring of water at barrages as well as in the Indus River.

Furthermore he emphasized the safety of barrages for maintenance of pond level as per design.

He was presiding over the review virtual meeting related with progress of Sindh Barrages Improvement Project- A rehabilitation and modernization of Guddu and Sukkur Barrages.

Project Director SBIP -Sindh Barrages Improvement Project, Ghualm Mohi U ddin Mughal, Project Coordinator Monitoring Unit Planning and development department Ehsan Leghari, Sajid Ali Bhutto deputy Project Director SBIP, Junaid Ahmed Memon World Bank Consultant, Dr Ali Asghar Mahesar deputy director environment, Abdul Razak Memon deputy director procurement SBIP Mr John Praytherch Project manager and Chirshall CRE Chief Resident Engineer also attended meeting.

Mr Francois Onimous said that almost it has been observed at three barrages more fluctional in pond levels which not only affect on withdrawal in canals but also impact on safety of barrage structure, therefore, pond level may be maintained ten dailies, monthly, quarterly and semiannual without any fluctuation which will be more helpful for security of the barrage and proper distribution of water in command area of barrages.

He further said barrages are facing silt deposition problems upstream of barrages and canal profile. Therefore, there is a need for sediment monitoring at barrage and canal levels.

He advised that there is an essential flushing of sediment, accumulated upstream of during medium flood flow.

Project Coordinator Monitoring Unit Planning and development department Ehsan Leghari and Junaid Ahmed Memon World Bank Consultant also stressed on developing standard of procedures, SOPs for sediment management at barrages level.

World Bank Task Team leader Mr Francois Onimous expressed that right canals of Sukkur Barrage Dadu, rice and NWC almost are facing sediment problems since construction of barrage of 1932.

He said that for addressing the problems of sediment in right canals, model study was carried out in Pona in India in 1947 which suggested ten gates permanent closure out of 66 gates of main barrage Sukkur, these closed gates have affected the barrage flood passing capacity but a silt problem some extent is facing by right canals at Sukkur Barrage still now.

SURVEY : During conditional survey of main gate canals work conducted by staff of Sukkur Barrage who found some defects/ damaged in six gates In December 2019. On an emergency basis, replacement of six gates were awarded to Karachi Shipyard.

In this context, the gates number 39 and 40 and 35 have been replaced, while work of replacement 34, 32 and 31 are under way and are in progress.

Remaining 50 and 165 gates of head regulators of canals and electro mechanic works bidding documents are under preparation and it may be completed and awarded up to December 2021.

Feasibly study: During it is worst mentioned in feasible study completed in 2018 that new Sukkur barrage may be constructed at Upstream or Downstream at existing barrage but during study, it was observed that there is suitable place of construction of barrage at same place otherwise there will be problems at construction at upstream and downstream of current barrage for diverting water at left and right off taking canals.

Feasible study further suggested that therefore there is only a single option that existing Sukkur barrage may be rehabilitated for more than 50 years or new barrage may be constructed in the same place. Furthermore for confirmation, international model study to be conducted for identifying suitable location of new construction of barrage. However, a panel of experts recommended that the civil structure of the barrage is stronger and more stable so that rehabilitation and modernization work of the barrage will increase the life of the barrage more than 50 years.

ESTIMATED PROJECT COST AND HISTORY: The project of rehabilitation and modernization of Sukkur Barrage has been initiated with world bank funding.

This project is covered with gate replacement of gates (50 main barrage gates and 165 canal gates), repair of civil structure, foundation inspection and investigation, electromechanics works, telecommunication and CCTV and building works.

Furthermore, dredging from left and right pockets of barrage and also canal silting from the right canal is about 25 kilometers.

Sukkur Barrage and off taking canals project were sanctioned in June 1923 and also construction started in July 1923. The Project was completed in 1932 with the largest single unified irrigation system/network of the world. Seven offtaking canals, three at right side and four at left side supplying water about 8.4 million acres are cultivable area of Sukkur barrage which is covered 80% of cultivated area of Sindh Province and maximum design flood passing was 1.5 million cusecs water but now flood capacity of barrage is reduced up to 0. 9 million cusecs of water due to permanent closure of 10 gates out of 66 main barrage gates.

Instead of 0.9 million cusecs flood capacity of Barrage, the maximum 1.2 million cusecs water passed from the barrage in supper flood 1976 and also in 2010. After operation for more than three quarters of a century, the barrage faced the number of problems, partially due to deficiency in original design, partially due to aging affects and partially due to its frequency of operation, which limited it to carry out the repair and rehabilitation work in timely manners. The problems are not only placed limited on its utilization, but even threaten its vary existence; major problems were experienced in the year 1947, 1985 and 2004. In 2004 a large scouring holes developed downstream of the first pile line in the first three spans of right under sluices resulting in collapse and damage of the first pile line and concrete slab in its vicinity. Cavities under format under the slab the sluice in front of head regulator in Dadu canal.

keeping in view the aged structure of the barrage and single source, supplying the water for agriculture, industrial and drinking purposes about 80% of culturable cultivated command area. Government of Sindh has almost kept his focus on the importance of Sukkur Barrage for not only the source of supplying water but also its beauty of structures recognized in Asia.

Therefore, a feasible study was completed in 2018 for rehabilitation and modernization of Sukkur Barrage. In rehabilitation of Barrage, civil and mechanical works will be carried out in main barrage structure. The RCC arches, stone machinery works, desk slab and barrage roads of main barrage civil structures will be rehabilitated while 56 gates of barrage will be replaced along with an electro mechanical system as well as hoist system.