The first indoor waterpark of size in North America was 1985?s World Waterpark in Alberta, Canada?s West Edmonton Mall. The idea of the waterpark as a vacation destination rather than a stop along the way grew from there.

In the United States, the Wisconsin Dells waterpark resort industry first came on the scene in the ?90s. The first large hotel in the Dells to add an indoor waterpark was the Polynesian Resort in 1994. Since then the region, already a popular tourist area, has become known as the center of this booming arm of the aquatics industry.

Over the past two decades or so, waterpark resorts have seen huge growth and expansion, according to David J. Sangree, president of Hotel & Leisure Advisors. As popularity of such retreats has spread, waterpark resorts as a whole have increased their number of guest rooms from less than 4,000 to nearly 30,000 in the past 10 years, Sangree says. In the same time period, the number of actual resorts has grown by almost 100, jumping from only 18 to 114 in 2007.

If all the square footage of these parks in the United States and Canada are combined, the amount of space adds up to approximately 4,500,000 square feet, compared with about half a million a decade ago. Major players constantly contributing to the increase include Kalahari Resort, Great Wolf Resorts, Maui Sands Resort, Coco Key Waterparks and The Valley of the Springs Resort.

The latter, currently under way in French Lick Ind., will include the largest-ever retractable roof structure and is pursuing LEED green building certification from the U.S. Green Building Council. Both of these trends reflect where much of the amusement trade will be heading in coming years.

While the travel industry is seeing a crunch due to rising fuel costs, this sector appears to be soaring. Part of the reason lies with constant innovation, Sangree says. Owners and operators are beginning to focus on keeping things fresh, adding new components and increasing expansion to attract new visitors and keep repeat customer coming back.