Downtown Blaine sidewalks pose potential construction problems

The city of Blaine’s downtown revitalization project has revealed voids under areas of the sidewalk on Peace Portal Drive that engineers are working to understand to ensure sidewalk construction doesn’t cause problems for the surrounding roadway, buildings or utilities. 

Cascade Engineering Group, a Bellingham-based company that the city hired to perform project engineering, discovered gaps underneath some areas of the sidewalk on Peace Portal Drive, located between buildings and the top of sections of a historic retaining wall. 

Greg Berg, project engineer for Cascade, presented the findings to Blaine City Council during its January 8 meeting. Berg told councilmembers the engineering group is trying to locate city documents to show where remnants of the retaining wall are located and how the wall was built so the engineers know how they can proceed with sidewalk construction. 

“Knowing exactly how they are built would determine what we can and can’t do,” Berg said. 

If the sidewalk is integral to the building and roadway, the city will need to replace the sidewalk through a more complicated and expensive process to avoid damages that could include depressions in Peace Portal Drive, disrupt utilities or cause structural damage to buildings. 

Berg said he hasn’t seen signs that the sidewalks are at risk of a complete structural failure, but to do a complete structural analysis, he needs the drawings of how the sidewalks and retaining walls were constructed.

“We would have to [replace the sidewalk] completely differently to make sure we don’t do damage,” Berg said. “It would be much more complicated than normal replacing.” 

The retaining wall, installed to level roads in central downtown, has documents dating it to at least 1932 and the wall was added onto in 1979. The sidewalk, elevated above ground level, was added next to the retaining wall, and Berg said the group doesn’t know when that project was constructed. The voids act as tunnels in some areas that were used for utilities and as coal chutes.

Cascade Engineering plans on asking city council for approval to conduct nondestructive testing, such as using ground-penetrating radar, to locate the voids under the city. The voids run deeper on the west side of Peace Portal Drive, Berg said.

“The big unknown, especially on the west side, is there could be voids next to these buildings that could have implications if we took the sidewalks out,” he said.    

The city of Blaine originally intended to complete a large-scale downtown revitalization project to improve Peace Portal Drive, from Marine Drive to Clark Street. However, in light of the city’s budget shortfalls, council decided last January to slim the project and only focus on necessary improvements, such as improvements to ADA accessibility, which includes the sidewalk replacements, and potentially utility improvements. 

The city is also focused on fixing trees causing uneven sidewalks along Peace Portal Drive, which will be addressed by either moving or replacing the trees. The Boblett Street and Martin Street parklets will also be revamped and downtown signage is expected to be added.

Cascade Engineering Group plans on designing a standardized downtown block that the city of Blaine will replicate as funds become available. 

The project is estimated to cost $2-5 million; it will cost close to $2 million if city council decides to only do sidewalk repairs but around $5 million if utility repairs are included. 

City manager Mike Harmon said public works is trying to understand the shape of the underground downtown utilities, but that is stalled because the city’s camera broke down.

“Right now we’re angling toward what we can afford and a replicable standard city block that we can build over time as we can afford,” Harmon said.

Harmon said the city secured $500,000 state funding that includes 700 linear feet of sidewalk work, and would lose the grant if the city doesn’t do a substantial amount of sidewalk replacement by the end of this year. 

Berg said Cascade Engineering Group is trying to incorporate previous studies the city has done on its downtown potential. 

“We’re also trying to incorporate those with the best of our abilities to make sure we know the history and the city doesn’t pay for the same thing twice,” Berg said of the studies.

The engineering group also found nine potential sites for hazardous materials, with the only high risk area being a known Washington State Department of Ecology cleanup site near G Street Plaza. Berg said potential soil contamination would add more project cost if the city needs to do underground utility work.

The cultural resources report showed no evidence of archaeological significance found in the project area, but monitoring will be required.  

Blaine Public Works Department is also watching a future Washington State Department of Transportation project that would uncover and restore part of Cain Creek to ensure the creek project doesn’t interfere with the downtown upgrades. 

The public will be invited to an open house on the downtown revitalization project concepts, which Berg hopes will be ready by late February, once the city has a better understanding of the state of its underground utilities.  

“Cascade Engineering can design as much as they want, but we need to build an affordable project and we have to be certain what we’re getting into,” Harmon said.