When Seattle city planners and the Washington State Department of Transportation decided that Highway 99 (also known as the Alaskan Viaduct), a 1950s era two-level highway traversing Seattle’s bustling waterfront that carries 110,000 cars each day, needed to be replaced, the concerns of one particular group of area residents were not taken into account.
It wasn’t the local business owners or Port of Seattle officials who weren’t included in a community focus group; it was the thousands of Norway rats, mice and other pests that have called the area home for decades. As construction continues on the $1.2 billion project to replace Highway 99 with a modern bi-level tunnel, rodent and pest activity levels are on the rise, much to the chagrin of local business owners.
While the massive construction project is not the sole cause for the rising rodent activity, it certainly isn’t slowing them down.
Scheduled for completion in late 2015, the 2-mile tunnel and accompanying infrastructure will dramatically alter, and hopefully improve, commuter flow and safety along the waterfront. Replacement options were first discussed following a magnitude-6.8 earthquake in 2001 that damaged the current Highway 99 structure. While many options were proposed and hotly debated, in the end advances in tunnel engineering technology swung the pendulum to going underground.
The actual digging of the tunnel began in June. Prior to that, workers excavated an 80-foot pit for the 57½ foot in diameter boring machine that carved its way underneath Seattle. Work on the pit and on surrounding infrastructure projects coincided with increased rodent sightings and pest activity.
“Rodent sightings were on the rise, as was feeding activity,” says A.J. Treleven of Sprague Pest Solutions’ Seattle service center. “The waterfront area of Seattle is the city’s oldest and has a well-established, robust rodent population.”
Treleven says the company also received a call from a commercial customer in a downtown high-rise building a half dozen blocks away from the construction zone with complaints of American cockroaches appearing in locations — such as the 20th floor of an office building — that they do not typically frequent. A possible theory for the cockroaches’ mysterious migration is that the noise and vibrations from preliminary construction efforts were driving pests away from the construction sites in order to seek less noisy accommodations.
Lots of Litter. Another contributing factor to the rising rodent activity along Seattle’s waterfront district is a solid waste recycling program offered by a private contractor to replace trash containers in alleys behind commercial buildings with daily garbage bag pick-up service.
While daily garbage pickup is an attractive option for local business owners, it doesn’t do much to deter hungry colonies of rodents from helping themselves to torn open or poorly secured bags of discarded food and waste.
Noted rodent expert Dr. Bobby Corrigan, who works extensively with the city of New York helping to curb the well entrenched and populous rodent population in the city’s subway tunnels, says increased rodent activity cannot always be blamed solely on construction projects and that Mother Nature plays a big role in the process.
“Rodents are very adaptable to the urban environment,” says Corrigan. “I’ve seen rats in the middle of subway tracks stay put as a train goes overhead and continue on their way when it passes.”
He says rats in urban areas have peaks and valleys in reproduction cycles that usually result in new litters emerging in late spring and late summer (early June and late August/early September). This coincides with the start time of many construction projects and gives the impression that every time you put a shovel in the ground rats pop out.
Corrigan went on to say that major construction projects, like the one in Seattle, can impact and alter the behavior of rodent and pest populations.
“If rodents have a nest below the sidewalk or next to the foundation of a building, and it physically vibrates or collapses, they will evacuate and seek out new harborages,” says Corrigan. “We call that a ‘direct hit’ on the burrow.”
Where exactly the dislodged rodents will go is anyone’s guess, says Corrigan, but rodents typically head up to ground level in search of a new home. This often leads these pests to probe the defenses of nearby buildings and find a way inside.
Corrigan says the key element in the rodent and construction saga is sewers, a favorite harborage location for generations of urban-dwelling rodents, primarily Norway rats. If the sewer is 75 years or older (as is the case in many major U.S cities) it is likely constructed of bricks, and as they fall out over time, rodents move in and burrow in the exposed dirt where the brick once held fast.
“Most major construction projects that involve tunneling or deep digging intersect sewer lines at some point,” says Corrigan. “When this happens rats will run down the sewers in search of a safer, quieter place to live. They will do anything to survive and this is when they pose the biggest threat.”
Be Prepared. It is this migration of desperate rodents that Treleven and his colleagues at Sprague Pest Solutions, a Tacoma-based pest management service provider now entering its fourth generation, are trying to prevent for business owners in the path of the tunnel project.
Sprague sent letters to business owners and property managers in the “rodent impact zone” alerting them to the potential rodent problem. Treleven says the letter’s message caught most recipients by surprise and that they were not aware of the potential for increased rodent activity as a result of the tunnel project.
“Customers in the area have dealt with rodents before but they did not anticipate the Highway 99 project potentially increasing the odds of rodents entering their buildings,” says Treleven.
Sprague’s message to business owners and property managers was to take proactive steps to physically exclude rodents before the tunnel digging gets underway.
“We explained it is easier to take preventative steps now rather than have to deal with rodents once they get inside the building,” says Treleven.
The company added capacity to its Seattle service center, armed its technicians with an expanded arsenal of exclusion materials, and provided additional training on new techniques on how best to exclude rodents from structures.
Sprague also added a page to its website (www.spraguepest.com/seattletunnel) dedicated solely to the Highway 99 project offering rodent prevention tips and encouraging customers to follow the latest adventures of Sven The Norway Rat on Twitter @ratpocalypse.
Proactive Control. Rodent expert Corrigan says that a proactive approach is the way to go.
“Regardless of what stirred up the rodents, it is best to error on the side of prevention,” says Corrigan. “Focusing on physical exclusion, baiting and trapping inside and out, and starting service before construction season gets into full swing are the keys to reducing rodent infestations.”
And while not every city has a tunnel project burrowing underneath its streets and sidewalks, Corrigan says it is important for pest management professionals to be preemptive in offering solutions.
“I want my pest management professional to tell me, ‘My surveillance is heightened and I will be vigilant in protecting your business,’” says Corrigan.