As well as losing crops and farm animals directly as a result of flooding, the people of Pakistan could be facing longer term food shortages as canals overloaded in the second wave of flooding threaten to undermine the irrigation infrastructure that the country will rely on once the waters recede.

The last three weeks have seen two flood surges along the Indus River, which starts in Tibet and flows through the whole length of Pakistan from north to south, to join the Arabian Sea near the port city of Karachi in Sindh.

In an attempt to manage the flooding, particularly following the second wave, it appears that water is being diverted from the river into irrigation canals.

In a Nature News report published on 20 August, James Dalton, an advisor for the International Union for Conservation of Nature Water Programme based in Switzerland, explained how the flood waves developed.

He said that the enormous damage from the first surge was due to dry and hard ground, so the water from the first rains just ran off into the river without being soaked up.

As the flood travelled south, the ground in the north gradually absorbed the water and soaked some of it up. But after it became saturated, the water from the continuing rains had nowhere to go but flood across the surface again.

In the meantime, there is no respite from the rains, and meterologists in Pakistan report that the waters from the first wave have merged with that of the second, with exceptionally high levels expected around the Kotri area, in Sindh, and that this will last until the end of the month.

Many embankments along the river in Sindh province are in danger of breaking, and to manage this, it appears that Pakistan officials have opened the irrigation canals as a way to relieve the pressure.

However, Chris Davey, a project director leading an irrigation project in Sindh being managed by a British firm, said he and other engineers are now worried that this could give rise to problems later, once the water levels have gone down, and water supplied by the canals is needed for crops.

According to Nature News, he and his team noticed something unusual was happening when they compared flows at barrages up and downstream of the river in Sindh. The downstream flow was much lower because the canals were being opened, something that is not normally done during monsoons, said Davey, “the way authorities have controlled the flood water is different to normal,” he added.

The authorities have also had to resort to carrying out a controlled breaching of the canals in places where even they were in danger of breaking. When this happens, the water is allowed to flow out of the canal system into the surrounding area, as happened in Jacobabad in Sindh, where 300,000 people had to be evacuated nearly two weeks ago.

The problem is with the canals that are not breached, because the water flowing from the Indus brings a lot of silt with it, and it builds up in the canals. This causes a gradient change along the canals, which can then impede irrigation when the floods recede, said Davey.

This is not the only suggestion that the flood problem in Pakistan is not a straightforward natural disaster, but one complicated by the presence of man-made water systems and their management.

Mushtaq Ahmed Gaadi, a lecturer at Quaid-i-Azam University, in Islamabad, who researches the political and social dimensions of natural resource management, suggests much of Pakistan’s flood disaster is because “structures meant to control flooding have partially caused and definitely exacerbated the flood problem itself”.

He recently wrote an article about the flood situation around the Taunsa barrage in the Punjab; the article was published online on 20 August, by International Rivers, a research, education and advocacy group that aims “to halt destructive river infrastructure projects”.

Gaadi writes that the flood trauma started as a breach of the embankment upstream of the Taunsa barrage, that caused the Indus to carve a new channel next to its original course with the result that the water soon found its way into the the extensive network of irrigation canals alongside.

This caused flooding of relatively higher ground that is rarely inundated by the Indus, says Gaadi, a native of Taunsa.

“Nature is responsible, yes,” he adds, but “we must not overlook the role that engineering structures have played in transforming the present floods into an enormous disaster unparalleled in the history of this region”.

Gaadi also writes that “local accounts and media reports suggest that the [Taunsa] barrage staff has failed to properly operate the newly installed motorized hoisting system”, resulting in ten gates not being properly opened, which if true, could be argued is the main cause of the flood disaster. He has called for an official inquiry into the incident.

Sources: Nature News, International Rivers.

Written by: Catharine Paddock, PhD