A Fourth of July thunderstorm rages above the Oahe Dam power plant, providing a stark contrast between natural and manufactured sources of power. Water drained from more than 243,000 square miles, an area almost the size of Texas, passes through Oahe Dam. The dam comprises 2.5 billion cubic feet of earth and 29.7 million cubic feet of concrete and can discharge 436,000 gallons of water per second at its peak. Generating electricity for use in areas of South Dakota, North Dakota, Minnesota, Nebraska, Iowa and Montana, each of Oahe's seven turbines has the capacity to power a city of 100,000 people.