A water park or waterpark is an amusement park that features water play areas, such as water slides, splash pads, spraygrounds (water playgrounds), lazy rivers, or other recreational bathing, swimming, and barefooting environments. Water parks in more current states of development may also be equipped with some type of artificial surfing or bodyboarding environment such as a wave pool or FlowRider.
Evolution of water parks
Waterparks have grown in popularity since their introduction in the late 1940s and early 1950s. The United States has the largest and most concentrated waterpark market, with over a thousand waterparks and dozens of new parks opening each year. Major organizations are  (International Association of Amusement Parks and Attractions) and WWA (World Waterpark Association)which is the industry trade association.
Waterparks emerging from spas continue to more closely resemble mountain resorts as they become four-season destinations-for example, Universe Water Park Resort, a member of the World Water Park Association, is themed to match the community in which it is located. The theme is intended to enhance the communities' destination appeal. Therefore, the amusement and leisure time industry is becoming more concentrated as winter sports are becoming commonplace themes in summertime water rides. A process of concentration can be observed in the hybrid segments of theme-, amusement-, and waterparks. Some waterparks are more spa-oriented; e.g. Schwaben Quellen, a member of European Waterparks Association (EWA) has no water slides, but instead has many saunas, steam rooms, "adventure showers", and relaxation-oriented water play areas.
In the 2000s, an effort to reduce long lines by introducing conveyor belts to lift passengers or use water jets.
A unique feature at a waterpark is ice skating. Deep River Waterpark in northwestern Indiana features ice skating thanks to cooling pipes that were added under their massive plaza during a recent expansion.
Indoor water parks
Main article: Indoor water park
The first-ever indoor water park was built in Edmonton, Alberta, Canada in 1985 at the West Edmonton Mall as part of the $1.2-billion-dollar Phase III expansion. Called World Waterpark, is the world's second largest indoor waterpark, over 217,800 sq ft (20,230 m2) in size. It includes the world's largest indoor wave pool, waterslides of varying degrees, tube rides, bungee jumping, and hot tubs. Tropical Islands Resort (Germany) with an area of 66,000 m² (710,000 sq feet) is currently the largest indoor water park in the world.
With 5 indoor water parks, Wisconsin Dells, Wisconsin, is recognized as the "Water Park Capital of the World." It showcases several of America's largest indoor and outdoor water parks (see Noah's Ark Water Park). Indoor water parks in Wisconsin Dells debuted in 1994 after the Polynesian Resort Hotel built the first one in the U.S. The success in extending the tourist season and turning water park resorts into vacation destinations has resulted in tremendous industry growth. Usually resort hotels featuring massive indoor water parks that are often reserved exclusively for overnight guests, companies like Great Wolf Resorts/Great Wolf Lodge and Kalahari Resorts have branched out from their origin in the Dells to open new locations around the country. Mt. Olympus Theme and Water Park (formerly Family Land) is another huge water park in the Dells.
The largest indoor water park in the UK is Sandcastle Water Park in Blackpool, England, which opened in 1986.
There are many water parks in Southern Europe where the climate suits a long season. For example in Portugal on the Algarve there are three main parks - Aqualand, Aquashow and Slide and Splash.