The City of Seattle has filed a civil suit against a skate shop that constructed a concrete skate bowl on Green Lake’s Duck Island in June as part of a sponsored contest.

Twenty unidentified people came to the island, an off-limits bird sanctuary, to build the small concrete bowl, initially winning the contest challenge put forth by Nike SB and TransWorld SKATEboarding Magazine to build a skate park or add/modify an existing one. The contest, “Nike SB Project 58 Do It Yourself,” gave skate shops $500 in giftcards to complete the project. The shops had less than a month to build, skate, film and edit a video of the project.

According to the Seattle City Attorney’s office, the 20 people who built the bowl were operating on behalf of 35th North, a skate shop on Capitol Hill. The shop is the only named defendant in the suit.

Duck Island is considered an environmentally critical area. The man-made island was initially built as a wildlife reserve, but lost that status in 1983. Humans are technically prohibited from the island, but in the past, people have gone to the island to drink and set up a rope swing. The skaters building the bowl cut down at least one tree and removed vegetation on the island, as well as left debris after completion.

According to the City Attorney’s office, “The restoration of Duck Island will include weed removal, storm water and erosion control, litter removal and planting of new vegetation and brush.”

The City expects to identify the 20 builders of the bowl as the litigation progresses. The City Attorney “ is still calculating potential damages and penalties, and expects the total sought at trial to be in the low six figures,” according to a press release.

After initially winning the contest through Nike SB and TransWorld SKATEboarding Magazine, 35th North was later disqualified from the $1,000 prize after contest organizers discovered the construction was not authorized.

35th North owner Tony Croghan has said to the Seattle Times that he didn’t know about the construction until after it was completed.

Seattle Parks, which maintains the island, issued a statement.

““As stewards of Seattle’s public parkland, we were saddened to see the misuse and destruction of Duck Island,” said the city’s parks superintendent, Jesús Aguirre. “We are thankful to our partners in the City Attorney’s Office for seeking to hold those responsible accountable for damage created.”