Would you know a dam if you saw one? Dams are huge concrete structures built to hold back water. Each includes a spillway—a channel to keep water from overflowing. Maybe you’ve seen dams but didn’t notice. Someone is noticing them. Journalists just spent two years digging deep into information about U.S. dams.

Here’s what they found: The United States has more than 90,000 dams. And many are old and damaged. Their foundations are cracked. Their spillways are too small. Lots don’t have the strength to hold back extra water.

When rivers swell with floodwaters, dams are strained. Nebraska’s Spencer Dam failed last year. It unleashed a wave of water carrying ice chunks the size of cars.

“When they fail, they don’t fail with warning. They just fail, and suddenly you can find yourself in a situation where you have a wall of water and debris racing toward your house with very little time, if any, to get out.” That’s Craig Fugate’s description of dam failure. He was an administrator at the Federal Emergency Management Agency.

In 1978, the Corps of Engineers began the first nationwide dam check. It took four years to inspect 8,818 dams. One third were declared unsafe. One of those dams was in a New York state park near Sloatsburg. It’s been 40 years since then. Nothing has been done to fix the dam.

Many other dams also aren’t safe—but they are still in use. Most dams are privately owned. Not all owners are able or willing to pay for repairs. Some states can’t even figure out who owns certain dams. In Rhode Island, there are 32 dams with safety concerns whose owners are unknown. Different states have different inspection rules for dams. Some states check their dams yearly. Others inspect dams once every five years. A compromised, broken, or leaky dam is bad news, but repairs are costly and complicated. It would cost $70 billion to fix all the nation’s dams! But just ask people who live near them. To them, a fix may be worth every penny.

God held back walls of water to protect the Israelites as they crossed the Red Sea. Imagine the pounding waves and sheer force of water that swelled against God’s mighty hand. Exodus 14:29 says, “But the people of Israel walked on dry ground through the sea, the waters being a wall to them on their right hand and on their left.”