flood control Oklahoma Dams Near Expiration Dates As Scientists Predict More Extreme Weather By Claire Donnelly & StateImpact Oklahoma • Jun 27, 2019 Claire Donnelly / KGOU Oklahoma has more than 4,700 dams. At least 30 percent of these flood control structures are at the end of their 50-year design life. With climate change expected to bring more heavy precipitation, can they hold up?