What's the Name of That Book??? discussion

So I came across this book at my high school library, I can't remember the exact year, but it was sometime between 2006-2010. I think it had a one-word title and I want to say it was something like "The Wave" or "The Tide" or "Splash" or something like that as it had to do with people living under water on an earth that had been flooded for a very long time. Some of the earth's population was above water, but most were below. The cover had a picture of blue water and someone, a young adult (I wanna say male) bursting out of the water. I also remember there was a city that was completely submerged and it had a water fountain in the middle of a square where people used to throw coins in. I think that later on in the story, a small group of young adult merpeople came to the surface to fight some sort of evil that was threatening their way of life. I vaguely remember a scene where the teens are in some sort of abandoned warehouse and that's where they'd make their plans. I think they joined forces with some land-dwellers as well. I wish I could remember more, but that title and the cover I described has been in the back of my mind for years and I'm dying to figure out what book it was from...!

This strongly reminds me of a short story by Joan Lennon I read in Cricket, called "In Search Of...".
Here's a link to it: http://www.readmeastoryink.com/storie...

No.... That's not it.... :/

Maybe Iris or Under Space: A Short Story or Sea Change?

Oh maybe Oceania: The Underwater City

Above World or Atlantia

Dark Life the second in the series is Rip Tide.

I thought it may have been Dark Life, but, if I remember correctly, the people living under the water didn't live in bubbles or anything like that. When I say they "adapted to life underwater" I meant that they grew fins and/or gills...
Also, I know for certain that I read the book sometime between 2006 and 2010 (I graduated high school in June 2010), which means that it would've been published sometime before 2010.

Thanks for all the suggestions though! If you think of any others, please send them my way.

The Lost City of Faar is the second book in the Pendragon series. This is probably a stretch because I barley remember the book so I don't remember if they had any gils or fins or much of anything about the plot but I thought it was worth a mention just in case. Good luck!

The Lost City of Faar by D.J. MacHale - Kirstin's suggestion

Dawn, are you still looking for this or did you find it?

The Drowned World The Drowned World, maybe?

Might want to check the Drowning Towns list.

Still out there, Dawn?

No response, moving to Abandoned folder.

Dawn (OP) was last active on the site in April 2017.