Tarbela Dam faces fast-moving silt delta

WAPDA official says silt could block tunnels

HARIPUR:

The inflow of potentially dangerous silt delta along with water is fast approaching Tarbela Dam, posing a serious risk to the reservoir.

The silt delta has turned into a full fledge ball which is slowly sliding into the tunnels of the dam and is currently only 6 kilometres away, officials said.

In case of a collapse, this silt mountain will block the tunnels and will deprive Tarbela Dam of irrigation supply and electricity generation. Therefore, there’s a dire need to take preventive measures on a priority basis and to save trillions of rupees from loss.

Chairman Senate Standing Committee on Water Resources has highlighted the issue and its gravity and has called on the authorities to take required measures before it is too late. As per reports, Tarbela Dam is the country's largest water reservoir and hydropower producer, acting as the backbone of the country's economy. However, the dam faces a high risk of being hit by the silt mountain present in the Tarbela Dam. The lake is 97 km long and averages two kilometres wide with a depth of 450 feet. It is also said to be 1,550 feet above sea level.

Over the years, a large quantity of sand and silt has been collected in the lake. According to WAPDA's study, some 0.5 million tons of silt and sand are added to the lake every day.

According to experts, since Basha Dam and Kalabagh Dam could not be built, it resulted in the accumulation of huge amounts of silt inside Tarbela Dam lake. Similarly, the delay in the construction of check dams and watershed programs at Tarbela is another reason for the silt to be deposited inside the dam.

Previously, the silt accumulation was 12 kilometres away from the main tunnels however now the distance is decreased to 6 kilometres which put the dam at very high risk.

In this regard, Former Chief Minister and Senator Pir Sabir Shah, chairman of the Standing Committee on Water Resources in the Senate, has said that the silt mountain has been named as Silt Delta. It is slowly approaching the tunnels and at this rate, it will take a few years to cross the tunnels.

However, if a part of the silt delta breaks for some reason, it will quickly approach and choke the tunnels leading to a catastrophe. In particular, it will completely block tunnel number one and tunnel number two of Tarbela Power Station, while tunnel number three, four, and five will remain safe due to higher altitudes. In case the vulnerable tunnels get hit, we will lose 5,000 MW of cheap hydropower and irrigation water which would in fact lead to a loss of trillions of rupees.

He further said that it is a matter of surprise that in the past, more studies were conducted on the issue of this silt, but today we have closed our eyes like pigeons and waiting for the irreparable damage to occur. Federal Ministry of Water Resources and WAPDA officials need to take urgent measures to deal with this looming crisis.

 

Published in The Express Tribune, September 5^th, 2022.