The great decline: Silt eating into Tarbela’s storage capacity, NA told

Accumulation of deposit poses a threat to the fertile agricultural land in the area.

ISLAMABAD:

The build-up of silt in Tarbela Dam, the country’s largest reservoir, is significantly reducing its storage capacity, bringing it down to a mere 33 per cent, the lower house of parliament was informed on Wednesday.

This accumulation of deposit has emerged as a threat to the agricultural land in the area, which could be deprived of up to 1.2 million acres of fertile land due to lack of water supply in the coming years, water and power minister informed the National Assembly in a written reply.

To stave off the possibility, the government tasked two multinational consultant companies to conduct a feasibility study and propose a plan to de-silt the reservoirs on a long-term basis. Subsequently, both expressed their reservations over the situation in reports submitted to the government.

According to the minister’s statement, water storage in the reservoir fell this year to 6.472 million acre feet against the 11.616MAF maximum storage capacity, making it the biggest reservoirs till Aug 24, 2013.  The drastic decrease of water level led Mangla Dam to emerge as the country’s largest reservoir with a present capacity of 7.392MAF.

Responding to questions, Asif said climate change was posing a challenge to the availability of water in the country. In its effort to deal with the water storage crisis, the government is building 18 dams and plans to complete them within the next five to six years.

Subsequently, infrastructure activities at Diamer-Bhasha Dam are in progress which has capacity of 6.4MAF. Similarly, work on Gomal Zam and Darawat Dams has almost completed. Both dams will have storage capacity of around 1.90MAF collectively. Whereas Hingol Dam, Winder Dam, Kurram Tangi Dam, Daraban Dam, Tank Zam Dam, Bara Dam, Papin Dam, Garuk Dam, Pelar Dam, Mohamand Dam, Ghabir Dam and Naulong Dam are expected to be ready within five to six years.

Asif assured the house that the Water and Power Development Authority (Wapda) was assigned to construct small- and medium-sized dams in four provinces and Fata to store 2.7 million acre feet of floodwater. In a written reply to the question of Muhammad Muzammil Qureshi, he said the reservoirs would help irrigate 0.37 million acre of new cultivable command areas.

Meanwhile, commenting on the issue, senior Wapda officials told The Express Tribune that there is dire need to de-silt the major dams like Tarbela and Mangla to recover their storage capacity. Keeping in view the continuous sedimentation, the government should take serious steps to preserve their storage capacity which has now drastically declined, they added.

Published in The Express Tribune, February 27^th, 2014.