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Dam alternatives?

July 10, 2018

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“THERE has never been a fair playing field when dams have been compared with their alternatives. Corruption and the power of the big-dam lobby … [has] meant that feasibility studies for new dams have regularly underestimated their costs and exaggerated their benefits,” writes Patrick McCully, director of International Rivers Network, UK.

A group of researchers from Oxford University analysed 245 dams built between 1934-2007 in 65 different countries and found that average cost overruns were 96 per cent.

Pakistan has recently suffered a staggering cost overrun of more than 500pc in the country’s Neelum-Jehlum hydel project.

Cost overruns in the accounting books may just be one issue related to large hydel projects. There are many other costs that are associated with unsustainability — displaced communities’ destroyed ecosystems, eroding river deltas, drowned scenic river valleys, wrecked nutrient-replenishing sediment cycles in the floodplains, and so on. These unintended, yet unavoidable, consequences have costs that are referred to as ‘economic externalities’, which are inevitably borne by one or more segments of society.

To light a 100-watt bulb, taxpayers have forfeited Rs100,000.

To top it all, dams have a limited useful life. Tarbela Dam has lost 36pc of its storage capacity within a span of just four decades. And as for Mangla Dam, only 35 years after its construction, we had to borrow money to raise its walls due to silting.

Because the dams have silted up we need to build more dams goes one argument. Another goes that because they silted up, we should do something different now.

Dams are supposed to control floods, store water and produce hydropower. Is there anything different we can do to contain floods and ensure storage and power?

Let us first look at the issue of flood control. Wapda’s report on the 1992 floods clearly articulates that there is no provision in our reservoirs “for flood control”; it is “only incidental”. So, it is already a myth that dams control floods. The 1992 flood is a good example — when Mangla Dam not only failed to handle a large event, but exacerbated the damage. Similar events elsewhere in the world have transformed modern flood management systems.

Today, for the sake of flood management, large structural interventions are avoided while adaptation plans conforming to the natural flow regime are put in place. These interventions employ tools and techniques, based on adaptation and risk management that help simultaneously absorb flood peaks and recharge aquifers. Such techniques are ideal to avoid the kind of situations we recently faced in Lahore after a heavy shower of rain. ‘Water sensitive urban design’ (USWD) in the urban areas, and river ‘riparian zone management’ in the rural areas are the techniques preferred in the modern world to manage floods and which are found to be far more effective than having large dams.

And what about the water storage function of dams? Through all the existing and proposed dams combined, we can store up to 50 MAF of water. However, our natural groundwater storage capacity along the major rivers is around 3,000 MAF, which can be managed using contemporary ‘riparian zone management’ systems mentioned here. So, it is a myth yet again that dams are the only way to store water. The city of Lahore alone has an aquifer the size of the Tarbela reservoir, and gets enough rains to replenish it if investments are made to implement USWD in the city. Both flood management and aquifer storage complement each other within the same USWD framework.

Finally, let’s take a look at electricity-generation alternatives compared to hydel power. Our latest hydropower project, Neelum-Jehlum, has cost taxpayers more than Rs1,000 per watt of power supply capacity — without taking into account debt-service interest. This means that just to light a 100-watt bulb the taxpayers have forfeited Rs100,000. The present-day solar technology installations in the world, however, cost under Rs50 for the installation of one watt of capacity. This is already 20 times cheaper than Neelum-Jehlum — yet another myth that hydropower is the cheapest power form. Electricity storage solutions like Tesla’s Gigafactory to save solar energy for the night and cloudy days are also around the corner. Technology for electricity generation and storage through solar power is improving and getting cheaper in the coming years. And luckily, Pakistan already lies among the zones with the best solar potential in the world.

So, we have USWD and riparian zone management systems which can potentially capture and manage floods and store up to 3,000 MAF of water in the aquifers — a staggering 20 years of storage. And solar power solutions are not only 20 times cheaper than hydropower today, they are getting cheaper.

It is time to start discussing alternatives to dams in mainstream discussions, without prejudice, based on the latest emerging knowledge and trends.

The writer is an expert in hydrology and water resources.

Published in Dawn, July 10th, 2018