Barrages under threat

OVERCHARGED and irresolute, the debate on the Kalabagh dam acts as a subterfuge to conceal the grave threats of existing mega water infrastructures. Over the past several decades, the Indus Basin has been fragmented and transformed by dozens of mega water projects. It is imperative to critically analyse both the technical flaws in these interventions and acknowledge their many adverse effects.

To start with, the Indus barrages encounter multifaceted problems, possible failure and, subsequently, disaster. For example, the Sukkur Barrage has significantly lost its capacity which was once 1.5 million cusecs and is now 900,000 cusecs. The latest reports suggest that 13 out of a total of 65 barrage gates are dysfunctional.

For the last several years, the barrage is being operated without proper compliance with crucial de-silting procedures and standards. The gradual formation of sand islands in the immediate upper reaches of the barrage, mainly because of the confined channel and obstructive weir, has rendered inefficient the barrage function of silt transportation.

There are serious concerns that the river can out-flank the main barrage in the event of a major or medium flood. By all signs, the river threatens avulsion, ie sudden course change, to return to its primordial position of some 3,000 years ago.

The breach of the Tori Bund during the Indus floods of 2010 had already increased the likelihood of such avulsion.

For five weeks, one-fourth of the river flows were diverted from the main channel which, in turn, helped to scour andwiden its new/old path. If the trend persists, not only will there be valley-level destruction the barrage structure too will be rendered purposeless.

The case of the Taunsa Barrage appears to be even more tragic and alarming. About three and a half years ago, the barrage underwent emergency rehabilitation thanks to a World Bank loan totalling $134m. The intervention was meant to mitigate the risk of structural demise and to modernise the barrage`s operating system.

However, a few months after the remedial works, the left marginal bund was breached and unprecedented devastation was seen dur-ing the floods of 2010. The estimated financial cost of the barrage dysfunction and subsequent flood disaster in Muzaffargarh district was to the tune of $6 billion.

Notwithstanding the expensive rehabilitation, the barrage is still considered to be a highly vulnerable hydraulic structure over the Indus River. The rehabilitation works failed to control perfuse subsurface seepage and the resultant forces of uplift pressure. The recent barrage sounding and probing reports that assess the stability of the structure confirm the sinking of loose stone and creation of wide pits on the downstream floor of the barrage.

The Taunsa Barrage is a classic case wherein an ill-conceived engineering remedy turned out to be the cause of colossal human tragedy. The construction of a secondary weir, ie an un-gated obstruction wall downstream, has triggered several adverse changes. It has worsened the problem of backwater flow, and helped to make way for a delta-like formation in the upper reaches, complicated barrage operations and increased the risk of structural failure and flood disaster.

The problems and risks of large-scale water infrastructures are innumerable. These infrastructure operation and replacement costs increase exponentially with each passing year. The World Bank estimates that Pakistan needs to allocate around $ 1.5bn annually to maintain and replace its fast deteriorating water infrastructure. These higher maintenance and replacement costs together with the increased risks of flood catastrophe have turned the existing mega water infrastructures into a white elephant.

What is the way forward? One obvious choice is to continue with costly engineering solutions which are the underlying cause of the present crisis. An influential clique of water managers, engineering consultants and international lending institutions has a strong vested interest in maintaining the status quo.

At present, large foreign loans are being acquired for the remodelling and rehabilitation of six barrages in Punjab and other associated hydraulic structures in the Indus Basin.

However, if the Taunsa and Sukkur barrages teach us anything, it is that engineering remedial measures are not only wasteful, they are also likely to worsen the crisis.

The other option consists of the recognition that the Indus Basin has already arrived at the initial stage of its closure in the aftermath of excessive development and water withdrawal. Basin closures occur when a river is no longer reaching the sea particularly in the dry season, thus contracting lakes and restricting the transportation of sediments.

Besides, reduced flows limit the control of salinity.

The point is not that our water officialdom is oblivious to the high risks and costs of a fragmented and overbuilt Indus Basin. Pakistan has recently pleaded, albeit with partial success, its case for river environmental flows before the Permanent Court of Arbitration for the settlement of a water conflict with India in the case of the Kishanganga hydropower project.

However, as noted by the PCA, Pakistan is pursuing double standards on the issue of environmental flows. While it asks India to abide by the imperative of environmental flows, its domestic approach and historical practice don`t match its claims in trans-boundary water-sharing. • The writer teaches at Quaid-i-Azam University Islamabad.

mushtaq_gaadi2000@yahoo.com