The only way to know what's going on underwater is to talk to those who spend their lives in it and come up to tell the tale. That's what we did with Nancy Elder and Steve Rubin, scientists with USGS who have been monitoring the Elwha River Delta for 10 years.

They've seen how it's changed since the dam was removed upstream in 2012.

"In some spots where there was a lot of algae, like 50% coverage, when you look at the bottom more than half of it is algae. It was nearly all gone," Rubin said.

Rubin says it's likely because of all the sediment the dam released when it was removed. The water it let loose carried with it tons of riverbed. That stopped light from reaching the bottom and feeding algae. But in the last few years, it's cleared up, and we wanted to see for ourselves.

The team showed underwater video of their research.

With the delta bed changing from gravel and rock to softer sand, fish like the starry flounder have found a new home. The same goes for adult Dungeness crabs, whose return has prompted a new crab fishery. A new kind of sea slug moved in and became the predominant of its species.

Now that the sediment's settled, kelp is returning as well.

The researchers have used plastic paper to record it all while underwater.

"Decorator crabs are crabs that decorate their carapaces. Like, when there was algae, they'd be covered in algae to help themselves camouflage. The year the algae wasn't growing, we found these guys covered in hydroids. I thought that was an interesting story of resilience for a species," Elder said.

Our trip with Elder and Rubin was the last dive day of their 10-year study. It was bittersweet.

"I really like trying to figure out what happened. I think about it a lot," Rubin said.

"When I was a kid, I grew up in Indiana and my hero was Jacques Cousteau. I used to go out in the rivers of Indiana and look around to see what kind of fish and critters I could find. Now I get to do this for 10 years on this project. It's awesome," Elder said.

The two divers hope to return someday, but say just because they're gone doesn't mean the story is over.

"These sites are still in transition. This story isn't going to end probably until I'm well in my grave and someone else who's a Jacques Cousteau enthusiast is diving in on it, using our data," Elder said.