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November 7, 2017



To build or not to build

Revelations about water scarcity, made by members of the Pakistan Council of Research in Water Resources (PCRWR) and the Indus River System Authority (Irsa), at a recent Senate forum are quite worrying. Both authorities  painted a gloomy picture of water conservation efforts and claimed that approximately $21 billion worth of water was wasted every year.

The experts also bemoaned the lack of water conservation strategies in the country and expressed an immediate need to build at least three Mangla-sized dams to conserve the water that is being dumped into the sea. Irsa members endorsed the long-overdue Kalabagh Dam.

This seems to be an exaggerated assertion because Wapda’s own figures about the flow of water fly in the face of this claim. Experts believe that the water flow pattern reveals that floods occur approximately once in a five-year period, which means that the average flow is 137.27 million acre-feet (MAF) per year.      But in the remaining four years, the availability of water remains only around 123.59 MAF or even lower. So, how can we have a whopping loss of $21 billion?

There is no harm in chalking out water conservation strategies. However, presenting large dams as a panacea is not wise – and that too at a time when the world is decommissioning large dams and searching for alternative ways of conserving water and producing energy. It isn’t prudent on the part of policymakers and the advocates of dams to brush aside the legal, technical and ecological aspects of such constructions. The genuine reservations of smaller provinces with regard to the Kalabagh Dam must be patiently heard and nothing should be done to undermine national unity.

It is widely believed that the Kalabagh Dam is a viable option. This is why it is important to raise technical questions about its storage and power generation facility. According to a detailed paper on this water storage facility, prepared by a team of experts led by the former Irsa chairman          Engineer Fatehullah Khan Gandapur (late), the advocates of this dam overlook a number of technical points while favouring its construction. Citing government studies, the team claimed that the Kalabagh Dam project is to be built on River Indus, about 210 kilometres downstream from the Tarbela Dam and 92 miles downstream of Attock – the confluence point of the Kabul and Indus rivers. The claimed storage capacity is 7.6 MAF, the dam’s height is 260 feet and the reservoir elevation is 925 feet.

Gandapur and other experts have claimed that: “the government-tailored feasibility reports… and other manipulated studies were completed in 1985 and these reports were given to the provincial governments in 1990 after being kept hidden as a high state secret for five long years”. This secrecy led to many speculations on various aspects ranging from the dam’s design to its estimated cost. The cost was $5 billion in 1985, $10 billion during the Musharraf era and experts believe it could even be more than that now.

The first complaint of small provinces is about the terms of reference (TORs). Experts from Khyber Pakhtunkhwa accuse Wapda of specifically directing consultants through the TORs to come up with a design at the exact location of Kalabagh and with the exact storage capacity of 7.6 MAF instead of asking them to suggest the best location. Experts also claim that the Kalabagh Dam’s consultants had suggested that instead of a dam another structure, like a barrage, should be constructed at Kalabagh. This is because a dam will not evacuate silt. As a result, the dam at Kalabagh will be hydraulically unfeasible due to rapid silting and a short lifespan.

According to critics, the capacity inflow ratio must be kept in mind while building a dam or a reservoir. This simply refers to a ratio between the capacity of a reservoir at a site and the average annual river flow at that site.

This ratio is vital to estimate and know the lifespan and service value of the project to establish its economic viability. According to Engineer Fatehullah Khan Gandapur and other expert Wapda has demonstrated utter ignorance in understanding the CI ratio and its great importance. For example, in the first instance, Wapda states that the “CI ratio of a reservoir depends upon the topography of the site”. Second, it states that the “CI ratio is not the only criteria for planning a technically-feasible and economically viable multipurpose project”. Third, the CI ratio of the Kalabagh Dam is shown in percentage as 0.069 percent.

Gandapur asserted that in the case of the Kalabagh Dam portion of the reservoir at Attock on the Indus, the capacity of the reservoir is 3.5 MAF and the average annual inflow is 90 MAF. The CI ratio, therefore, amounts to 3.5:90 or   1:26. This is a ratio and is never expressed in percentage. Therefore, Wapda is wrong to show the CI ratio as 0.069 percent. The CI ratio shows rapid silting and short lifespan with a poor service value for the project, he added. So, the experts asserted that       the Kalabagh Dam’s CI ratio (1:26) is the poorest in the world. Iftikhar Ahmed, an expert, agreed with Gandapur on the issue of the CI ratio.

The possible rapid silting is another factor that belies the claim of the site being the best option. Critics claim that heavy silting will take place in the 3.5 MAF Attock portion of the Kalabagh Dam reservoir against the heavy inflow of about 90 MAFs of water. The muddy River Kabul is also contributing about 110 million tonnes of silt, which is equal to 0.1 MAF, annually in addition to 0.2 MAF of silt flow from the Tarbela reservoir. In addition to that, restricted mid-level sluicing as opposed to unrestricted sluicing is another factor that puts question marks on its viability. Sluicing is the process of extracting or pushing out silt from the reservoir using the flow of the river. Exit points are provided in the dam which, when opened, let the water out along with the silt that it carries. The lower these exit points are, the more silt is carried out. The higher they get, the more silt is left behind on the riverbed.

As an alternative, experts believe   that we should go for the multipurpose Katzara Dam, which has a storage capacity of up to 35 MAF, a 15,000 MW power generation capability and more than 1,000-year lifespan. According to an estimate from 2011, it will cost about $7 billion and can be accomplished in seven to eight years given its excellent site.

According to expert Munir Ghazanfar: “Nearly 60 percent of water gets wasted because of [the] flood irrigation system, mainly through seepage and percolation through canals distributaries, and water courses into the ground leading to water logging. Only 40 percent reaches the fields but, in fact, a mere 30 percent is actually needed by the crops”. So, this loss of water must be prevented by introducing efficient methods of irrigation. Many experts believe that instead of building large dams we should opt for aquifer storage and encourage greater efficiency in the use of water, especially in the agricultural sector, as it can save more than 10 MAF of water and end the need for large and expensive dams.

The writer is a freelance journalist.