The city of Mercer Island has four major roadway projects on its docket this summer with a total cost in the $3.4 million range.

Projects that are currently underway are the East Mercer Way landslide repair, street-related utility improvements and the 81st and 82nd avenue water system improvements. The project involving arterial and residential street overlays is slated to begin at the end of June or early July.

According to city street engineer Clint Morris, who has been employed by the city for the last 30 years, the overall cost for each project includes amounts for engineering and design, project management, construction inspections and contingency.

Neptune General Contractors was expected to complete its installation of a 75-foot-long soldier pile retaining wall in the 5600 block of East Mercer Way by the fourth week of June, Morris said. On Nov. 28, 2020, a small landslide piled into the shoulder below the guardrail, and a portion of the road was closed for approximately a week.

Following the completion of the structure — which includes nine steel pilings — a new guardrail will be installed in front of the wall, the temporary traffic signals will be removed, and the roadway will be returned to two open traffic lanes.

Morris said things have moved swiftly on the project, with design work beginning in February and construction starting on June 1. After the city opened construction bids in late April, city council awarded the project and authorized emergency repair funding in May.

Due to the pandemic, Morris was worried that some industries might have ceased production of the needed steel I-beams and cribbing material for the wall or that inventory might have been running low. He was also concerned if a drilling contractor would be available. Shortly after opening bids, everything fell into place and the project was a go.

This isn’t the first soldier pile retaining wall that has been erected in the city, Morris said.

“Mercer Island is a little bit prone to some landslides in a wet winter. We just don’t know where they’re going to happen. But to have a little slide like that happen along East or West Mercer Way is not necessarily unusual. I’d say maybe that happens every decade,” he said.

On the street-related utility improvements front in the areas of Southeast 62nd Street/82nd Avenue and East Mercer Way, contractor Blue Mountain Construction Group is scheduled to complete minor storm drainage and water system repairs by the end of July to make way for street repaving this year.

“We video inspected all of the storm drain systems within the streets we were going to pave this year and we found some small areas of damage that need to be dug up to be repaired,” Morris said. “The best time to do that dig up in the street would be before you pave instead of after.”

Some homes with old galvanized water pipes — which are notorious for developing leaks — will be changed out to help minimize future utility cuts in those streets, Morris said.

At the beginning of May, contractor Pacific Civil & Infrastructure started installing new eight- and 12-inch water mains in the area near the community center on 81st and 82nd avenues and a portion of Southeast 24th Street.

“I believe that’s set to be completed (by) late summer or kind of in that time period when school is starting,” Morris said.

Contractor Watson Asphalt Paving Company is handling the arterial and residential street overlays, which will begin soon and pave about 1.3 miles of East Mercer Way with fresh asphalt spanning from Southeast 53rd Street to the 6600 block, plus a small residential area comprised of Southeast 62nd and Southeast 64th streets, 82nd Avenue and 83rd Place. The project is expected to be completed by the end of August around the same time as the water main project.

“On paving any of our arterial streets, my goal is always to try and have it paved and striped before school starts,” Morris said.

Morris said that with the exception of the retaining wall project, this is a normal workload the city fits into its schedule each year.

The arterial and residential street overlays and water system improvements projects sit at the high end of the total cost spectrum at $1.3 million and $1.5 million, respectively.