Production on Dimension Films Piranha 3-DD, the unexpected sequel to Alexandre Aja’s well-reviewed-but-dead-in-the-water Piranha 3-D, got started today in Wilmington, NC. Directed by 2005’s “Project Greenlight” winner John Gulager (Feast 1-3), the film is headlined by 23-year-old horror fav Danielle Panabaker (The Crazies).

The film’s plot crunch reads:

There’s something in the water… again. And this time no one is safe from the flesh eating fish as they sink their razor sharp teeth into the visitors of the best summer attraction, The Big Wet Water Park.

Costarring with Panabaker are former Miss California Meagan Tandy (Unstoppable), Matt Bush (Halloween 2), Chris Zylka (Shark Night 3-D), David Koechner (Final Destination 5), Jean-Luc Bilodeau (”Kyle XY”), Hector Jimenez (Nacho Libre), and a bevy of nameless, top-heavy starlets.

Piranha 3-D opened in August of 2010 to rave reviews from both critics and horror fans. Despite starring such stroke-worthy babes as Kelly Brook, Riley Steele, and Jessica Szohr, the film tanked at the North American box office. Fortunately, it grossed over $63 million worldwide, making it profitable enough to merit a sequel.

Panabaker’s creds include Platinum Dunes’ Friday the 13th reboot, John Carpenter’s The Ward, and the Kevin Costner serial killer drama Mr. Brooks. The pretty 23-year-old is part of Clatto’s list of The 20 Hottest Women Working in Horror/Sci-fi Today.

Unstable Ground has released a new trailer for indie writer/director Justin McConnell’s post-apocalyptic thriller The Collapsed. The film centers on the Weaver family as they attempt survive the day-to-day dangers that living in a lawless and socially decayed civilization can bring.

The Collapsed stars John Fantasia, Steve Vieira, Lise Moule, and Anna Ross as the Weavers. Costars include a bunch of additional peeps I don’t know and Kassandra Santos, who stars on The CW’s “Nikita.” Raven Banner Entertainment will release the frightener in Canada on May 27.

No word on a U.S. date, but peep the trailer: