Huge allocations were made for large-scale projects in the first Five Year Plan. Which Dam was constructed from it?

Bhakhra Nangal Dam.

The First Five Year Plan addressed, mainly, the agrarian sector including investment in dams and irrigation. The agricultural sector was hit hardest by Partition and needed urgent attention. Huge allocations were made for large-scale projects like the Bhakhra Nangal Dam.

The Bhakra-Nangal Dam, also known as the Bhakra Dam, is a concrete gravity dam on the Sutlej River in the northern Indian state of Himachal Pradesh.
The dam is one of the largest and highest gravity dams in the world. The Bhakra Dam was built to provide irrigation water and hydroelectric power to the states of Punjab, Haryana, Himachal Pradesh, and Rajasthan.