October 27, 2020

Catching Lost Water By Rainwater Harvesting And Construction Of Small Dams  

By adminbacha

Catching Lost Water By Rainwater Harvesting And Construction Of Small Dams  

Pakistan is projected to become the world’s fifth-largest country by 2030, with a population somewhere between 230 and 260 million people. This projected spurt in population is alarming Islamabad policymakers, if for no other reason than the additional water requirement this will mean. Already the lowest in Southasia, over the next two decades    dam construction Mornington peninsula     Pakistan’s per capita availability of water is expected to drop by more than 37 percent – from 1100 to 700 cubic metres per person per year.

In particular, this demand would put significant stress on the country’s massive, complex Indus Basin Irrigation System (IBIS). Begun in 1859, the IBIS is currently considered the world’s largest water-diversion scheme, boasting nearly 60,000 kilometres of canals and distributaries, punctuated by two large dams. The looming step-up in demand for water, coupled with poor water governance, could thus lead Pakistan from its current state of water stress to being an outright water-scarce country before long.

Much of this issue hinges on Pakistan’s poor ability to store water. The country’s current water-storage capacity is barely 12 million acre-feet (an acre-foot refers to the amount of water necessary to cover an acre of land to a depth of a foot, a bit more than 1230 cubic metres). This figure represents only 10 percent of the country’s annual river flow; the world’s average for storage capacity, on the other hand, is 40 percent of a country’s annual flow. The two large dams in the Indus Basin Irrigation System, the Mangla and Tarbela, originally offered a cumulative storage capacity of 17.5 million acre-feet. But this figure has been reduced by almost a third due to silting over the past half-century, and will go down further in the near future. Indeed, it is this ‘lost’ water – continuously coursing through Pakistan and on into the Arabian Sea – that has become the primary focus of national and international planners alike. Unlike elsewhere in the region, Pakistan’s dam-building plans are not focused on energy production, but rather on catching some of that water before it disappears.

In recognition of the developing crisis, in 2001 the government, with the support of international donors, developed a plan dubbed Water Vision 2025, a blend of various strategies that add up to a roadmap for the country’s water-sector development. Water Vision 2025 identified three potential large-dam sites on the Indus – the Kalabagh, Bhasha and Akhori dams (see table). But this strategy was formulated without considering the fact that the IBIS has already wreaked havoc on the country’s environment. Water diversions have, for instance, turned large tracts of Sindh into desert. The US-based International Rivers Network has dubbed the IBIS “a prominent example of how corruption pervades economic development and distorts the priorities of infrastructure investment.”