A $70 million water park featuring high-speed thrill rides and state-of-art water slides is to be built in Perth's north-eastern suburbs.
In one of the most significant tourist attraction developments in WA in decades, the park will sit on 4ha as part of The Maze Fun Park in Bullsbrook.
The $1.5 million first stage - a three-storey-high waterslide playground with two tube slides, two flume slides, toddlers' slides, a 1000-litre tipping bucket and a range of water cannons and interactive play features - is expected to be finished by December after getting planning approval from the City of Swan and a $250,000 grant from the Federal Government this year.
"Our team is ready to begin work to ensure that our guests will be splashing and sliding on Australia's largest waterslide playground by summer," co-owner Phil Dixon said.
To be known as Outback Splash, the park will be built in six stages over 10 years.
It will include up to $15 million for nine waterslides, up to $15 million for a lazy river and $5 million for food and beverage outlets. Existing facilities at The Maze will also be expanded to include nine different mazes and mini-golf.
The Maze has been operating for 34 years and was bought by Paul and Nicole Woodcock - operators of the successful Wanneroo Botanical Gardens and Leapfrogs Cafe - in 2006.
Mr Woodcock appointed his brother-in-law, Mr Dixon, as the park's general manager and they eventually became partners in the business.
Since they took over, annual patronage has increased from 21,000 to about 90,000 people.
Two years ago, surveys of patrons found that a water park would be popular and work began on the planning, including discussions with experts around the world.
"Heat has always had a negative impact on the park, so adding water makes great sense and seemed like it would be a lot of fun," Mr Woodcock said.
"Dad always said that if you do it, do it well - so we dreamed big and arrived at Outback Splash."
One of the park's initiatives will be a water filtration system that will mean the stage-one playground will need only the same amount of water to operate as an average backyard swimming pool.
City of Swan mayor Charlie Zannino said the park was an exciting development that would expand on the activities and attractions of the region.
"Through our 2012 visitor survey, we found about 32 per cent of people who visit the Swan Valley come for family fun," he said. "Respondents were asked to indicate if there were other activities they would like to see developed and the highest ranking suggestion was for adventure or recreational activity.
"We anticipate the water playground will help to meet this need and be popular with local residents and visitors."
Tourism Council chief executive Evan Hall said the water park was a fantastic project and exactly what the local tourism industry needed.
It is planned to operate Outback Splash from October to April each year, with patrons paying only an entry fee.