FOOTPRINTS: When LBOD overtops its banks

Updated 13 Sep 2020


NAUKOT: Labourers are strengthening wooden cage at the site of breach of the 
Left Bank Outfall Drain system in the Naukot area. — Umair Ali
NAUKOT: Labourers are strengthening wooden cage at the site of breach of the Left Bank Outfall Drain system in the Naukot area. — Umair Ali

WHILE mobility on the highly bumpy embankment path remained badly affected with fewer options to cap a 400-foot-wide breach, labourers refused to give up and with strenuous efforts for nearly two weeks finally emerged victorious.

The breach in Left Bank Outfall Drain (LBOD) system’s spinal drain at RD-287 in the Naukot area of lower Sindh region, battered by monsoon downpour in August, was fixed at last.

With no direct access to transport material such as bamboos, gunny bags filled with soil and other items — essentially required in plugging a breach — challenges for the labourers and irrigation officials were many.

Plugging such a wide breach, I am told, in such conditions is no less than science.

The drain was getting consistent flows of rainfall’s runoff from its catchment. The heavy flow of water, almost three times higher than the drain’s capacity, continued uncontrollably. Piles of gunny bags were dumped on the drain’s right bank from one end to other to be ferried to the left bank and handed over to labourers through boats. Onlookers’ presence was making the job more difficult, prompting officials to seek assistance of police to disperse them.

Varying sizes of bamboos, mostly eucalyptus tree, were brought in a sizeable quantity. A few workers kept on sharpening the woods to keep supplies going so that stilts are properly pitched in the drain’s wet bed and to hold ground to sustain water pressure.

A fence-shaped structure was then crafted with woods tied together tightly. Inclined and supports were ensured for strengthening reasons. Initially, labourers had no option but to offload bags from boats between the two ends of the breach. Groups of labourers stayed in boats and threw bags in bed till they attained a matching height with the bank’s edge. This allowed workers to stand on sacks, as the erected wooden frame, supported by soil-filled bags, lessened the intensity of water flowing from the breach towards Tharparkar district. Subsequently, soil was dumped there to strengthen the embankment.

The labourers, covering lower part of their body with only a piece of cloth, worked many hours a day for nearly two weeks. Frequent visits of officers to the site boosted their morale, as quite a few enthusiastic workers roared “Ya Ali” in unison whenever they witnessed the visiting officers, who waved and responded with a smile.

“We are mostly fishermen, hailing from Sanghar district. Our munshi negotiates payment with irrigation officers as our labour charges,” one of the fishermen, who were of varying ages, tells me after eating spicy rice for lunch arranged at the site.

“Flows in drain during rainfall can’t be controlled and when drain overtops its bank, the overflow of water takes away the bank’s soil with it and causes a breach. During torrential rains such system or drain behaves like a river,” explains Zareef Khero, irrigation department’s chief engineer development region-II with considerable exposure of international irrigation systems.

To drain out rainwater standing in their fields, some farmers also dig through the connecting branches of the spinal drain, which weakens the structures, the official elaborates before endorsing recommendation of some other experts that the “whole LBOD system now needs review and remodelling”.

Documents of International Panel of Experts (IPoE) of the World Bank’s May 2005 report, Louis Berger’s 2013 study and a recent presentation given to Pakistan Peoples Party chairman Bilawal Bhutto-Zardari, show that LBOD Stage-I project was executed in 1984-1997 as federal government (Wapda’s) project to relive water logging and salinity in 1.27m acres of Mirpurkhas, Sanghar and Nawabshah districts.

LBOD’s spinal drain was handed over to the irrigation department in 1993 but it did not perform well and caused damages in 1994 rains. It was returned in 1995 to Wapda that again gave it back to Sindh Irrigation Drainage Authority (Sida) seven years later.

Now it lies with Sindh irrigation department. It remains a perennial problem for rural population and authorities for want of maintenance. LBOD was designed for 125mm rainfall in five days, but in just 24 hours, 214mm rainfall was recorded in Mirpurkhas in 2011 and 169mm this year. Certainly, it will be catastrophic if such amount of rainfall continues for five days.

The 2013 study considers “rehabilitation of LBOD system as high priority intervention” while the IPoE report, which was prepared after the 2003 flood damages, described “LBOD a new river” and its tidal link carried a flow at least two times the design discharge of 4,400 cusecs in 2003 floods. This warranted the outfall system be re-designed and LBOD’s right embankment reinforced besides construction of escapes from left bank of the spinal drain.

The study “regional master plan for left bank of river Indus, delta and coastal zone” was carried out under Water Sector Improvement Project-I of Sida. It had proposed three components involving expenditures of Rs43,565 million, but funding remained a problem.

LBOD system virtually works like a storm-water drain sans its re-sectioning, de-wedding and rehabilitation. It looks a classic case of deferred maintenance and to quote one officer “no lessons are learnt regardless of disasters it spelt in 1994, 1999, 2003 and in 2011”. Combined flows of Puran dhoro (a Sindhi word for old natural waterway) and Mirpurkhas Main Drain (MMD) find their way into LBOD system’s largest trunk, spinal drain, at RD-297 while carrying flows from different catchment.

Mehmood Nawaz Shah, a progressive grower, can’t help expressing his concern and tells me that the fact LBOD is with Sindh government doesn’t mean federal government should turn a blind eye to it. “It needs re-assessment and augmentation. Being lower riparian Sindh needs a well-functioning drainage system,” he insists.

CE Khero is worried, too. “We have to pay serious attention to around 20-30 miles strip of the drain before 2021 monsoon at all cost. Extreme weather events give us surprises regularly and we should not keep things lying down,” he asserts.

LBOD’s outfall structure is non-existent that leads to sea intrusion. Some rehab works were done after 2011 damages to the system, but as a decade has passed since then, LBOD system will be a pain in the neck if left unattended. And being an engineer himself, Sindh Chief Minister Murad Ali Shah understands it well.

Published in Dawn, September 13th, 2020