HYDERABAD: The Kotri Barrage chief engineer has urged the irrigation secretary and chief engineer of Sukkur Barrage’s right bank canals that the data regarding release of quantum of water from Manchhar Lake over the last 10 days be shared with his office so that any mishap could be avoided and safety of the vital structure (Kotri Barrage) could be ensured.

CE Haji Khan Jamali, it is learnt, has sent such wire to the officials yesterday (Sept 5) in view of floodwater discharges observed at Kotri Barrage on the day.

According to the wire, Sukkur Barrage had released a flow of 579,000 cusecs on Aug 25 but Kotri Barrage received 603,000 cusecs upstream on Sept 5 — up by 40,000 if calculation at the Kotri Barrage were anything to go by. He wrote that water flows were released from Manchhar Lake without intimation to the Kotri Barrage region.

Kotri Barrage received a flow of 603,327 cusecs upstream and flow of 584,272 cusecs was passed downstream on Monday at 6pm. This peak passed through the barrage till today (Tuesday) with a discharge of 604,147 cusecs upstream and 583,822 cusecs downstream recorded at 6pm.

CE seeks statistics of last 10 days after higher than calculated peak passed on Monday

Guddu Barrage continued to record a declining trend in discharge with 247,922 cusecs upstream and 244,342 cusecs downstream. Sukkur barrage is now in high flood with a discharge of 388,122 cusecs upstream and 388,122 cusecs downstream.

Kotri Barrage’s off-taking canals — seven in all — are closed and, therefore, the up and downstream discharges remained the same. No withdrawal of water was being made at canals.

CE Jamali explained that “in fact everyone knows flows from Manchhar Lake are ending up in Indus river through Aral Wah; these flows, however, remain unaccounted for since they are not brought on record”.

He said that the purpose of sending this canal wire was necessary so that in future all such discharges were reflected in statistics to enable the Kotri Barrage management to have a clear idea of upcoming flows.

“I had expected a peak flow of 500,000-550,000 cusecs at the [Kotri] Barrage while seeing 579,000 cusecs flow Sukkur Barrage downstream flow of Aug 25 after 10pc travelling losses. The percentage of losses between Sukkur and Kotri are on a higher side in normal conditions given time lag and bed’s width between two barrages,” he said.

But, he said, flows at Kotri Barrage had increased substantially to hit a flow of 604,000 cusecs which did not tally with the calculation done at barrage. “Flows from Manchhar Lake were not brought on record, but it is necessary to make this a permanent practice in future. It will enable the authorities concerned to have correct estimates of flows and make arrangements for flood-fighting accordingly because densely population cities run parallel to the Kotri Barrage.

Gauges to be examined at Aral Wah

To a query, Mr Jamali said he had asked his director hydrology, Habib Ursani, to measure gauges at Aral’s head and tail regu­la­tors of Manchhar lake. “The officer will be reaching the point as he is returning from upper Sindh. After examining the gauge, he will be recording the flows,” he said.

Mr Jamali’s contention was that the lake’s flows joining Indus river near Sehwan needed to be brought on record and they should not remain ‘unknown flows’ in future. “Flows from Manchhar Lake need to be documented in future,” he stressed.

Meanwhile, an increase of just 1,000 cusecs was reported at Kotri Barrage between 6pm Monday (603,327 cusecs upstream) and 6am Tuesday (604,147 cusecs upstream). According to Mr Jamali, it’s ‘local waters’ that entered Indus river at some location. Since 6am, the flow at upstream remained unchanged till 6pm today.

Kotri Barrage has a designed discharge capacity of 875,000 cusecs. It passed a flow of 939,442 cusecs downstream (on Aug 27, 2010) during super floods after receiving a flow of 964,897 cusecs upstream.

Then in 2015 floods, the barrage passed a high flood of 603,084 cusecs downstream and received 634,919 cusecs upstream.

Published in Dawn, September 7th, 2022

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