Work is on track to relocate the King County District Courthouse in Bellevue next spring, allowing the outdated and contaminated facility currently in use to be leveled and improvements to Surrey Downs Park to start.

The city is nearly a year into its 11-year lease for 29,500 square feet of office space in the Bellefield Office Park, and designs are now being finalized for tenant improvements.

“It will be a much improved space for the court and the public that uses it,” said Civic Services Director Nora Johnson.Johnson said the sale of the 15-building Bellefield office campus earlier this year did not complicate the city’s plans, and the same company continues to manage the complex. Under the lease agreement, the landlord will cover the cost of tenant improvements, not including about $5 million the city will spend on upgrades.

The new district courthouse will consist of a central lobby, with three wings around it that include three courtrooms and administrative offices. About 5,000 square feet of space will be for probation services, Johnson said.

Parking will be under the building, where a “sally port” will be used for inmates during prisoner transport to and from the courthouse. This will be a marked improvement over the current facility on 112th Avenue Southeast, where inmates are brought in from an uncovered parking lot. One inmate was able to escape custody in broad daylight last January, and wasn’t apprehended until a month later.

“We will have a much safer way to get them into the building,” Johnson said. “While it’s extremely rare to to have an issue with that, it’s still something we want to avoid.”

The current district courthouse was constructed in the 1960s and has been used by the county since 1986.

Demolishing the current King County District Courthouse is anticipated to occur once the new facility opens in May and take six weeks to complete, due to a number of contaminants on the site needing to be removed. That includes a potentially leaking transformer and asbestos in portions of the building that will need to be hauled away during 68 roundtrips over a three-week period, according to the city’s Weekly Permit Bulletin.

A water line and side sewer will be capped and abandoned by the city following demolition of the 22,000-square-foot structure. Sedimentation collectors will be constructed on the site to prevent contaminants and sediment from entering storm drains and nearby water sources.

Once demolition is completed, the city can begin work redeveloping the Surrey Downs Park, the 2009 plans having to be revised after Sound Transit announced its East Link light rail guideway would be running near the courthouse site.