World Bank Task Team leader Francois Onimous has emphasised the establishment of a barrage management unit which will work on repair, maintenance and operation of Guddu, Sukkur, and Kotri barrages besides monitoring water level at barrages and the Indus River.
He was presiding over the review virtual meeting related to the progress on the Sindh Barrages Improvement Project (SBIP) that pertains to the rehabilitation and modernisation of Guddu and Sukkur barrages.
SBIP Project Director Ghulam Mohiuddin Mughal, Monitoring Unit Planning and Development Department Project Coordinator Ehsan Leghari and others attended the meeting.
Onimous said that fluctuations in pond levels have been observed at the three barrages which not only affects the withdrawal in canals but also the safety of the barrages structure. He said in order to minimise the damage, pond level may be maintained without any fluctuation for the safety of the barrages and proper distribution of water.
He said that the barrages were facing silt deposition problems that required sediment monitoring at barrage and canal levels. He said that there was essential flushing of sediment, accumulated upstream during medium flood flow.
Project Coordinator Ehsan Leghari and World Bank Consultant Junaid Ahmed Memon stressed developing SOPs for sediment management at the barrages level. Onimous said that the right canals of Sukkur Barrage are facing sediment problems since the construction of the barrage in 1932.
He said that to address the problems of sediment in the right canals, a model study was carried out in Puna in 1947 that suggested permanent closure 10 gates out of 66 gates of the main barrage.
These closed gates affected the barrage flood passing capacity but the silt problem to some extent still persisted.
SURVEY: During a conditional survey, the staff of the Sukkur Barrage found some defects in at least six gates in December 2019. On an emergency basis, a replacement contract was awarded to the Karachi Shipyard.
In this context, gate numbers 39 and 40 and 35 have been replaced, while work on the replacement of gates 34, 32 and 31 was underway.
The remaining 50 and 165 gates of head regulators of canals and electro-mechanic works bidding documents are be prepared a contract may be awarded by December 2021 to fix these issues.
FEASIBILITY STUDY: According to a feasibility study completed in 2018, a new Sukkur barrage cannot be constructed Upstream or Downstream of the existing structure.
It was observed that there was no suitable place for the construction of the barrage except the place where it is currently constructed. In case, the barrage is constructed somewhere else, there will be problems concerning water diversion and canal distribution.
The study further suggested that, therefore, there was only one option that was the rehabilitation of the current structure for at least 50 years or the construction of a new barrage in the same place.
Furthermore, for confirmation, an international model study needed to be conducted for identifying a suitable location for the construction of the new barrage. However, a panel of experts recommended that the civil structure of the barrage was stable and could last for 50 more years after rehabilitation and modernisation.
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 replacement of gates (50 main barrage gates and 165 canal gates), repair of the civil structure, foundation inspection, investigation of electromechanics works, telecommunication and CCTV, and building work.
Furthermore, dredging from the left and right pockets of the barrage and canal silting from the right canal were also on the cards.
Sukkur Barrage project was sanctioned in June 1923 and the construction started in July 1923. The project was completed in 1932 with the largest single unified irrigation system/network in the world. Seven off-taking canals, three on right side and four on left side, are supplying water to about 8.4 million acres cultivable area. The maximum design flood passing was 1.5 million cusecs but now the flood capacity of the barrage was reduced up to 0. 9 million cusecs due to a permanent closure of 10 gates out of 66 main barrage gates.
Instead of 0.9 million cusecs flood capacity of the barrage, the maximum 1.2 million cusecs water passed from the barrage in during a flood in 1976 and in 2010. The barrage faces a number of problems, partially due to deficiency in the original design, aging effects, and its frequency of operation that limited the scope of the rehabilitation works.
The problems are not only placed limited on its utilization, but even threaten its very 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. Keeping in view the aged structure of the barrage and single source, supplying the water for agriculture, industrial and drinking purposes about 80% of area of Sindh, the government of Sindh has almost kept its focus on the importance of Sukkur Barrage.