November 22, 2006	Wednesday	Shawwal 29, 1427

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ISLAMABAD, Nov 21: The Indus River System Authority (Irsa) has agreed to a two-month canal closure plan to complete the repair works of Taunsa barrage in the Punjab and, as a result, the lower provinces would get their water indents at Guddu.

According to sources in the Punjab government, under the closure-cum-diversion plan sought by the Punjab, Taunsa barrage will remain closed from December 11 to February 10. The water losses arising out of the canal re-routing would be borne by the Punjab, and a maximum of 20,000 cusec would be allowed to pass through Taunsa barrage for the initial few days.

A committee comprising irrigation officials of the Punjab and Sindh would be posted at the Guddu barrage to ensure correct monitoring of provincial indents, they said, adding that an inter-provincial meeting of the irrigation authorities is being convened in the next few days to formally approve the canal closure and diversion plan.

For indents to reach Guddu barrage on December 11, the provincial water share from Jhelum zone would be released on December 2. The Rs8 billion rehabilitation of the Taunsa barrage is a project of the Punjab government, and the World Bank is providing about $125 million.

During the repair works, releases through Taunsa barrage would be limited to 20,000 cusec for the period between December 11 to January 15, which would be increased to 25,000 cusec on January 16. This would be further enhanced to 45,000 cusec per day from January 21 and till February 10.

The barrage was originally built in 1953 but was on the verge of collapse before it was taken up for repair last year. The consultants of the project believed the weaknesses were so serious that it could cause failure in near future.

The rehabilitation has three components. The first part relating to rehabilitation and strengthening of walls includes a 4,300 feet long subsidiary weir located 1,500 feet downstream of the barrage to raise the tail water level, ensuring proper energy dissipation at high river flows; repair of the barrage floor by removal of weak concrete and replacement with a new layer of concrete; and grouting to seal joints and fill voids in the foundation. This would also include sediment mitigation measures for the DG Khan canal at the right bank and installation of a safety monitoring system by placing some critical monitoring instruments in the barrage and its foundation.

The second part would include renovation of gates and appurtenances for barrage and canal head works. This component involves renovation of the barrage gates and hoists and improvement in the operating and control system.

The third part covers consultants for feasibility study, detailed design and construction supervision of Taunsa barrage and detailed designs for rehabilitation of five other barrages, namely, Jinnah, Khanki, Suleimanki, Trimmu, Balloki and Islam.

Almost all the major barrages, built decades ago, are in need of rehabilitation to take care of aging, design and construction defects, changes in hydrological conditions, and deferred maintenance. The main problem encountered in the older barrages is erosion at the downstream toe, due in part to changes in river hydrology.

Another problem is the loss of integrity in the downstream floor leading to loss of soil from the foundation. Gates and hoists are also in most cases in need of renovation. River training works upstream of the barrages also need some improvement. These problems are present in varying degrees of severity at all of the older barrages.

The Taunsa barrage diverts a part of the Indus flow to two large canal commands with an irrigated area of two million acres and to other large areas served by the Taunsa-Panjnad Link Canal. This link canal transfers water from the Indus to areas served by two rivers, the Ravi and the Sutlej.