Originally constructed in 1974, the Tarbela Dam is the world s largest earth- and rock-filled structure, standing almost 500 feet high and straddling the Indus River for 9,000 feet. Its existing hydropower facilities supply about 16% of the electricity generated in Pakistan. The primary purpose of the Tarbela Dam Project was to regulate the flows of the Indus River for irrigation use. This project is in fact part of a wider set of infrastructure projects, the so-called Indus Basin Irrigation System (IBIS), which is the world s largest irrigation system. Other objectives were to achieve substantial generation of hydroelectric power and flood control by conserving snow melt and monsoon flows of the Indus River.