WATERLOO - Construction is nearly complete on what should be the first hydromagnetic rocket water coaster in the country.

Wailua Kapua, which translates to purple Hawaiian river dragon, is in the final stages of being assembled at Lost Island Adveturepark in Waterloo, thanks to mild temperatures.

"The other (water coaster) in Santa Claus, Ind., is also planning on opening in 2010," said Lost Island general manager Eric Bertch. "If the weather cooperates, we should be the first ones completed."

The water coaster is schedule to debut in June 2010, in time for Lost Island's 10th anniversary. The park is planning fireworks, live music and other specials all season to celebrate.

Wailua Kapua is the first new ride since 2008, but it's also one of the first of its kind. Only 10 such hydromagnetic water coasters exist in the world, Bertch said.

Riders get in a boat that take them down sharp drops like other water rides, but then four sections work like a roller coaster, taking participants up hills.

It works not by the weight or the speed of the boats, but through a series of linear induction motors that propel the boats up the hills at roughly the same speed they descended them.

Another difference is the way riders get to the entrance of the slide. Instead of a series of stairs, riders take a conveyor to the top.

Bertch wouldn't say how much Wailua Kapua cost except to say it was "the most expensive addition that we've ever put in." Lost Island's ticket prices will increase by $2 next season to accommodate for the new slide.

But he is counting on the ride bringing more people to the park.

"Having this major, major addition to the park, and the fact that we do try to keep everything new to the guests, we're really going to hit it this spring with a heavy marketing plan touting the 10-year anniversary to try to reach out further than we have in the past," Bertch said.