As a play area, it rains cool water in the summer and ices over in the winter — fun for kids, but unbelievably tricky for engineers.

With a pirate ship centerpiece ringed with a rainbow of water sprinkling tubes, the water park at Langford’s City Centre Park is nearly completed.

It doubles as an ice skating rink, with three miles of refrigeration piping underneath the 3,100-square-foot concrete slab, all to keep two inches of water frozen.

Balancing Vancouver Island Health Authority drainage regulations and the physics of freezing is no easy task. The spray park slope must be steep enough to stop water from pooling, but too steep and creating ice becomes impossible.

Where most spray parks have a central drain, Langford’s has nine points to keep water flowing out. Grey water is stored in a seepage pit and then stormwater ponds for overflow, said Mike Leskiw, a Langford’s parks planner.

“We’ve had five engineers help us through this,” Leskiw said. “It’s very complex, it’s one of a kind. You can’t pull this out of a plan.”

Langford plans to have the refrigeration system installed and the rink up and running this winter. The water park, budgeted at $250,000, is next to the site for the future City Centre Park ice arena.

“We are going to tie the two together,” Leskiw said. “We’ll have a concrete pad that can freeze so people can skate inside and outside.”

Eagle Ridge arena will operate the water park and will open depending on the weather. The rink will be covered with a marquee tent in the winter and frozen when the air temperature drops below 10 C.

Greg Hillman, co-owner of Accent Refrigeration Systems, said the park underpinned with the same amount of refrigeration equipment as a NHL-sized arena. Outdoor ice is generally difficult to maintain, he said, although certainly not impossible.

“That the rink is covered (with a tent) is huge,” Hillman said. “Rain is a killer, it will eat the ice. Wind is a factor and the solar load is huge too. Sunbeams on one side can melt it all.”

Creating outdoor ice involves cooling the concrete to -10 C and misting layer after layer of water so it bonds together.

“For a small surface there’s a lot of work in there,” he said. “And there aren’t many refrigerated splash parks with a pirate ship.”