Breakthrough achieved in 2nd tunnel of two-tunnel Veligonda project, marking its completion

VELIGONDA: A breakthrough was achieved in the second tunnel of the Poola Subbaiah Veligonda Project in the Prakasam district of Andhra Pradesh on Tuesday.

With this, the construction works of two tunnels have been completed with only minor works to be finished. Megha Engineering and Infrastructures Limited (MEIL) used two Tunnel Boring Machines (TBMs) to complete the construction of both tunnels.

Excavation of tunnels for this project was started 15 years ago. In 2020, MEIL started excavating works in both tunnels which are 3.6 km and 7.5 km long respectively. MEIL completed the 3.6-kilometer-long first tunnel in January 2021, in just 13 months. The first breakthrough was achieved after 12 years of work in the first tunnel. On Tuesday engineers achieved a breakthrough in the second tunnel which is 7.5 kilometers long. The AP Government appreciated the officials, contract agencies, and the staff who worked on the successful mission.

The Water Resources Department of the Andhra Pradesh Government has taken up the excavation of two tunnels from Kothur near Dornala in the Prakasam district to Kollam Vagu in the upper reaches of the Srisailam project in the Nallamala forest area. Engineers designed to dig the first tunnel in seven diameters and the second tunnel in 9 diameters. The length of each tunnel is 18.82 kilometers which would be able to move 3,000 cusecs of water from the first tunnel and 8,500 cusecs of water from the second tunnel.

After YS Jaganmohan Reddy came to power, the MEIL took up the works of two tunnels. In 13 months MEIL completed the excavation of 3.6 kilometer long first tunnel works. After completing the first tunnel break through second tunnel works started and it achieved the breakthrough on Tuesday.

The completion of the two tunnels and the water withdrawn from the Srisailam project will greatly benefit the people of the western Prakasam district, along with Nellore and Kadapa districts. In Prakasam, 3.5 lakh acres, 80 thousand acres in Nellore, and 30,000 acres in Kadapa will get irrigation water from this project. This project will also provide drinking water to 16 lakh people of 30 mandals in these three districts.

Asia’s longest conveyor used

In the Veligonda tunnel project, a 39-meter Asia’s longest conveyor belt has been used. It is used to take out stones and mud that come out during the excavation of the tunnels. The works were completed without any auditing in these tunnels. Auditing is done during the construction of the tunnel. It is a passage through which a hole is made from the surface of the tunnel to move machinery, goods, and workers in case of an emergency.

Due to the non-availability of this auditing passage, MEIL had to face several problems in this project. It had to transport cement, sand, iron materials, and machinery required for the construction from Sangameshwara in Kurnool district to Kollam Vagu area through River Krishna by two barges that could carry a weight of 125 and 800 tonnes. from there the material was taken to the Veligonda project construction area.

The barges used to take 10 hours to move these supplies. To move staff and labour, speed boats were used from Srisailam Dam to the project site. In case of any untoward incident, it takes at least two hours to bring the personnel from the project construction site. The workers had to endure the high temperature inside the tunnel, which could go up to 60 degrees.

P. Rambabu, MEIL Project Manager at Poola Subbaiah Veligonda project said: “We have completed the project by overcoming all the ordeals faced during the project. We had to get fresh water through boats. But our staff and workers achieved the target. As the entire project is situated within the Neelam Sanjeeva Reddy Tiger Sanctuary, we had to take all precautions. No work should be done here to disturb the wildlife. Everyday work would run from sunrise to sunset only. After that, there should be no movement of any vehicle or machinery.”

The construction major followed all the rules while completing the project work. Even during the pandemic, the company has taken special measures with the support of the government so that the work is not hampered. All precautionary measures have been taken to reduce the impact of heavy rains, and floods which occur every year.

Water from next season

Purardhana Reddy of the Water Resources Department of the Andhra Pradesh Government witnessed the Veligonda project's second tunnel breakthrough and said: “The Veligonda Tunnel is a difficult project and we have completed it successfully. Although the project is in Tiger Sanctuary, we have followed all rules while executing the project. And we assure you that water will be released through these tunnels in the next season.”