HYDERABAD, Oct 20: The agriculture sector of the province has proved to be highly prone to natural disasters, like heavy rains and floods, thanks to disappearance of old natural drainage system and serious faults in the alternative system designed to replace the old.

The old drainage system, with a few modifications, had been working efficiently for decades before landowners and influential persons started grabbing its land and the department concerned turned a blind eye to the land grabbers and the system’s upkeep for obvious reasons.

This led to a virtual blockade of the system and an alternative drainage system was put in place namely, the Left Bank Outfall Drain (LBOD) and the Right Bank Outfall Drain (RBOD).

Currently, in the event of a flood the Indus River carries the floodwater to the Arabian Sea — provided its embankments are in sound condition — and if there are heavy rains, the rainwater flows into the LBOD and RBOD which take it to the sea.

But both systems are not designed to carry rainwater.

The mega drains, which have been primarily designed for carrying saline water only, have serious design faults at different locations.

A World Bank report had proved that the Wapda-built LBOD’s outfall structure was not properly designed with the result that saline water flowed back up the drain causing serious damage in lower Sindh districts of Badin, Mirpurkhas and Thatta.

Naseer Memon, a social activist and environmentalist, said that the WB team had compiled a detailed report on each component of the LBOD project, including its monitoring, designing and execution stages and revealed that all the components had serious defects.

The drain caused serious damage and inundated many rural and urban settlements during the 2011 torrential rains. Encroachment of old waterways also aggravated the situation.

“LBOD’s components cover some areas and not all areas located on the left bank of the river,” said Idris Rajput, an irrigation expert. But when the drain overflows it wreaks havoc on farmland and nearby human settlements.

“We need to focus on multiple options for drainage. We must clear old waterways that have been heavily encroached if we have to tackle heavy rainfalls in future, which seem to have almost become routine because of changing weather patterns,” he said.

“I have proposed to the government to either redesign the RBOD with a capacity of around 15,000 to 20,000 cusecs or put in place a different system of drainage for rainfall runoff,” said Mr Rajput.

This year’s heavy rainfall in areas on the right bank of the river as well as hill torrents coming from Balochistan inundated large swathes of land mainly in Jacobabad, Kashmore-Kandhkot and Kambar Shahdadkot.

The rainwater caused a siphon of RBOD-III, which has been left unfinished, to open up and threatened nearby farmland and villages.

Gada Hussain Mahesar, a representative of the Sindh Abadgar Board (SAB), pointed out that there were several small drains in upper Sindh but they were never de-silted nor were they maintained.

The drains were covered with an overgrowth of weeds which had reduced their capacity to carry water to the main drain and pumps installed for disposing of water did not work, he said.

“The old waterways — called dhoro in Sindhi — have been encroached upon and influential people have converted them into fishponds,” he said.

RBOD-III carries water up to Hamal Lake from where Main Nara Valley Drain (MNV), also referred to as RBOD-I, takes excess water to Manchhar Lake.

The RBOD-II was designed under the Musharraf government to save the Manchhar Lake and also carry water coming from Balochistan. It was to carry saline water up to the Arabian Sea and drop it into the Gharo creek.

But the entire project has been left unfinished for the past several years because of lack of funds and reservations by people living near them and other stakeholders.

Representatives of farmers’ organisations agree that the drainage projects should be completed immediately to drain out rainwater in the event of heavy rains and avoid disasters.

“If an individual or group has objections to the mega drains they should disclose them but they should also come up with solutions to the drainage problem,” said Mehmood Nawaz Shah, a senior SAB leader.

But, he argued, the status quo over RBOD-II or RBOD-III was not helping either. “Sixty to 70 per cent of the drain’s structure has been built. It should be completed immediately and put into operation,” he said.

He said that LBOD did create problems but it was ultimately the same drain that carried rainwater up to the sea. Similarly, RBOD could also serve as another outlet for disposing of rainwater, he said.

SAB president Abdul Majeed Nizamani agreed with Mr Shah. “I think RBOD needs to be completed immediately because it provides the only route to rain or saline water coming from upper Sindh region and Balochistan. Besides, billions of rupees have been spent on it so far,” he said.

He said that at present there was no alternative to RBOD. “The drain gets closer to the river at one or two locations and engineers need to ensure it causes no harm to the river’s ecology,” he said.