Complex sentence: The Kuybyshev Reservoir has a surface area of 6,450 km² and a volume of 58 billion cubic meters, and is the largest reservoir in Europe and the third in the world by surface area the largest and second largest are Lake Volta and Smallwood Reservoir.
Split into simpler sentences: The Kuybyshev Reservoir has a surface area of 6,450 km² and a volume of 58 billion cubic meters. It is the largest reservoir in Europe and third in the world by surface area the largest and second largest are Lake Volta and Smallwood Reservoir.