 Record rainfall and stormwater runoff overwhelmed the 114-year-old Rapidan Dam near Mankato recently. It's the result of the wettest April through June on record for Minnesota. And these climate change enhanced rainfall events, they threaten nearly 92,000 dams across the U.S. Many are over 100 years old. So just how safe are our 20th century dams in our new 21st century climate?