HYDERABAD: Sindh irrigation authorities were now plugging breaches of Manchhar Lake and Main Nara Valley Drain (MNVD) for two reasons – start rehabilitating the system and avoid further accumulation of water near Bhan Syedabad where floodwaters are flowing in to Indus River.

Initially, a cut on Manchhar Lake’s embankment at RD-14 is being plugged. Once it is done, the irrigation department would turn to the RD-52 location for closing the breach. At the same time the authorities are also working to close multiple breaches of the MNVD, or Right Bank Outfall Drain-I, built by Wapda.

“We are now plugging MNVD’s multiple cuts and that of RD-14 of Manchhar lake,” Irrigation Secretary Jamal Mangan, said alluding to breaches in MNVD which are adding to water accumulation near Bhan Syedabad, Karampur (it remained safe) and Talti areas and entering Indus through cuts in Larkana-Sehwan bund (LS bund).

As Manchhar started brimming with floodwaters entering from upper Sindh through MNVD and situation became serious, the department gave cuts at RD-14 on Sept 4 and later at RD-52.

Cut in LS bund to be closed at the end of work

KN Shah still under water

MNVD had already developed multiple breaches at that time due to immense pressure of gushing flows coming from upper Sindh. Suprio bund had suffered breaches and the resultant flows drowned Khairpur Nathan Shah taluka (Dadu district) which is still under water.

During a recent hearing of a petition, Sindh High Court’s Hyderabad circuit bench had expressed its concern over continued inundation of KN Shah. Dadu Deputy Commissioner Murtaza Ali Shah had informed the bench that much of floodwaters had receded from KN Shah and pumping was under way to drain the remaining quantum.

Flows from relief cuts on Manchhar’s dyke had inundated large parts of 10 union councils of Sehwan taluka. The lake was also emptied through Aral Wah’s head and tail regulators. Both the regulators normally dispose of water from the lake into Indus.

“The irrigation system is needed to be rehabilitated and it is to be ensured that water from MNVD’s cuts should not flow towards Bhan Syedabad any further so that life in villages around this or Talti towns could start returning to normal,” said Mr Mangan. Otherwise, he said, if cuts in MNVD remained opened, water would keep accumulating near Bhan Syedabad.

Plugging of LS Bund breach

“Once these breaches of MNVD are closed, flows will travel to Manchhar Lake. The same will be released through Aral’s head and tail regulators,” he added. This pocket has to be emptied now, so that villages around it also stand cleared. “Cuts in LS bund of Indus river will be closed in the end, he said.

Wapda’s chief engineer (water), Sukkur, Naeem Qadir Mangi said that Sindh government had started rehabilitating system of Manchhar Lake and MNVD to avoid release of more flows towards KN Shah.

Three cuts on the dyke of Indus Link -- a channel between RBOD-I and RBOD-II -- would be closed, he said, and explained that the cuts were given on RD-6 (MNVD), and RD-215 and RD-216 of Indus Link. The exact locations of the cuts remained a bit unclear as the area remained inaccessible. Now the actual site would be confirmed once plugging work begins.

“All these cuts were given during flood-fighting and now these are to be closed”, he said. He noted that water was still coming to MNVD from upper Sindh. “In fact it is horizontal sheet of water stretched on an area of 8-10kms. This needs to be emptied before system is normalised,” CE Mr Mangi said.

He said that Aral head, as per its designed discharge, could release 10,000 cusecs and Aral tail regulator had a capacity of releasing 25,000 cusecs. “If a flow of 30,000 cusecs or so keeps entering the lake from MNVD, this will be managed accordingly through the two regulators,” he said.

Earth filling is continuing at RD-14 of the lake and once it is strengthened, the machinery would easily be moved to the second location of RD-52.

NHA repairing highway

Meanwhile, the National Highway Authority (NHA) has also started repairing a section of Indus Highway in the area where a cut was applied to give way to floodwaters towards Indus River. A culvert, damaged due to deluge pressure, would also be repaired.

This would enable the irrigation authorities to reach Bhan Syedabad from Sehwan. Commuting between Sehwan and Dadu via Indus Highway as an alternative route of LS bund had stopped due flooding after relief cuts were given. Officials approach Bhan Syedabd through Dadu-Moro bridge over National Highway.

Wapda has completed RBOD-I/MNVD and lately offered its control to Sindh government but the latter declined to take it over on the grounds that RBOD-II was still incomplete and also had a “design fault”.

Published in Dawn, October 9th, 2022