The Friends of Lake Sammamish State Park, state parks officials and state and city lawmakers held an open house for the park’s newly constructed Sunset Beach Bathhouse Tuesday night. The event unveiled the Washington State Parks system’s vision for construction in the “park of the 21st Century’ — as noted in Lake Sammamish State Park’s vision statement — and marked the end of a more than decade-long process to see the project to completion.

“For me, this has been a personal experience,” said Peter Herzog, Washington State Parks and Recreation’s assistant director of parks development. “Working here as a young kid and, now, seeing this … come to fruition, it’s really amazing.”

The building, designed by Patano Studio Architecture, is a roughly 3,000 square foot concrete structure curved to emulate the Sunset Beach shoreline and containing concessions, gendered and family bathrooms, a lifeguard station and a multipurpose “flex space.” Its roof contains rain gardens that will grow over time and an array of photovoltaic cells to reduce the building’s energy costs by an estimated $3,500 per year.

“Each day, this building makes enough energy to drive a Tesla from Seattle to Spokane,” architect Christopher Patano said. He added, with a laugh: “Just one way.”

The structure is decorated with planks of redwood sourced from a Northern California dam. Exposed to the elements, the planks will age and create the appearance that the building has been in Lake Sammamish State Park “forever,” Patano said, though the concrete shell will prove exceedingly durable.

“(It) isn’t going anywhere, ever,” Patano said.

The total cost of the project was $2.6 million, Herzog said. The Washington State Legislature only recently approved funding to staff lifeguards at the beach, though Herzog noted that if funding had not been approved, lifeguards would have been provided via partnership with the city of Issaquah.

The city annexed Lake Sammamish State Park into its boundaries in 2014, making the city responsible for the cost of law enforcement on the water and putting project permitting in its jurisdiction. Mayor Fred Butler said he hoped permitting would be able to be fast-tracked in the future.

The bathhouse is already in service and Park Manager Richard Benson noted it was one of the building’s smaller features that seemed to be most popular.

“The showers are what everybody loves about the place,” he said.