In Curitiba, Brazil, they believed that, "Every river has the right to flood." So they built parks with dry ponds along the river. When it flooded, no one got hurt and the excess water filled the dry ponds, slowing its progress downstream.
Here's an article about green infrastructure in the context of Harvey. I noticed in particular this best practice:
Philadelphia has one of the most aggressive low-impact development strategies. Since 2006, it’s required all new construction over 15,000 square feet to have its own systems capable of handling 1.5 inches of rainfall to alleviate pressure on its aging stormwater infrastructure.The Cities Of The 21st Century Will Be Defined By Water - Fast Company