Complex sentence: Constructed of rock covered with clay and other earth, with a concrete spillway originally designed to carry vehicular traffic, the dam wall is 51 metres high and 1,616 metres long, and at 100% capacity can hold 3,000,000 megalitres of water.
Split into simpler sentences: Constructed of rock covered with clay and other earth, with a concrete spillway originally designed to carry vehicular traffic. The dam wall is metres high and kilometres long, and at 100% capacity can hold 3,000,000 megalitres of water.