The comings and goings of garbage trucks at the city's proposed intermodal solid-waste transfer facility being considered for Harbor Island wouldn't much affect other traffic, according to a transportation consultant.

Garbage trucks from throughout the city would haul their loads to the planned facility, where the refuse would be compacted and placed inside sealed containers for shipment by train to a landfill in eastern Oregon.

Planners from Seattle Public Utilities and their private consultants presented the results of their draft supplemental environmental impact statement to the public at West Seattle High School last week. In addition to transportation impacts, planners also studied how much odor and noise such a facility would create. Its effects on water quality, plants and animals were studied too.

Engineering consultants Heffron Transportation studied traffic patterns around all four sites being considered by Seattle Public Utilities for the future garbage-handling facility. Two sites being studied are in the area around the former Fisher flour mill. Two more potential sites are in Georgetown.

The rate of growth in traffic around Harbor Island was projected to the year 2028. Future increases in the amount of garbage Seattle will generate and the corresponding up tick in the number of garbage trucks it will take to haul future solid waste also were calculated.

Planners anticipate two peak traffic times at the planned garbage facility. Commercial haulers gather trash downtown during the night and they would take their loads to the facility during early morning. Then garbage trucks serving residential neighborhoods would arrive around 3 p.m., just before the evening commute starts.

Calculating projections to the year 2028, consultants determined there would be an average of 286 garbage trucks per day taking loads to the enclosed facility by then. That would be enough additional traffic to have an effect on congestion around Harbor Island, but not enough to overly impact the efficiency of nearby intersections, said Marnie Heffron, principal at Heffron Transportation.

Traffic engineers rate intersections "A" (best) to "E" (worst) according to the "level of service" they provide. The intersections by Harbor Island would slip from "B" to "C," but that would still be considered a passing grade for those intersections, Heffron said. The consultants studied the intersections at Spokane Street and Klickitat Avenue; 16th Avenue and Lander Street, and East Marginal Way and Spokane Street.

The study briefly considered the effect on garbage-truck traffic of replacement of the Alaskan Way Viaduct, since about 70 percent of the waste would be coming from north Seattle. Planners concluded that the detours around that massive construction site would affect southbound garbage trucks regardless of whether the intermodal solid-waste transfer facility is built or not. Therefore the issue was not studied.

Only about 40 people attended the public meeting but there was skepticism about the study results.

"It's impossible that there would be no impact (on transportation)," said Tim Beaver, whose Global Diving is located on West Marginal Way.

Beaver also said it would be a mistake to build such a facility on Harbor Island and take up already scarce industrial waterfront. Although the facility is planned to have a dock so that garbage containers could be shipped by barge, the primary mode of shipment will be by rail. Therefore there is little need for a waterfront location, Beaver said.

Rich Berkowitz agreed that using waterfront property for a garbage transfer facility would be a mistake, especially when container shipping is on the increase and waterfront jobs pay so well.

Patti Mullen, executive director of the West Seattle Chamber of Commerce, argued that garbage trucks certainly would affect traffic on the West Seattle Bridge. She also reminded officials how much West Seattle residents rely on the bridge, especially when it comes to medical care. West Seattle has no hospital.

"It's disingenuous to say trucks won't have an impact," said Dennis Ross of the Admiral Community Council. He claimed the West Seattle Bridge traffic is already 20 percent over capacity, so it's incorrect to say hundreds of garbage trucks traveling each day to Harbor Island wouldn't have an effect.

Terry Williams, president of the Southwest District Council, seemed incredulous too.

"Traffic is a major, major concern," he said.

He also criticized the fact that citizens had just 17 days to submit comments about the environmental impact statement. Public comments are due by March 21.

Cindi Barker of the Morgan Community Association said she used to live in Covington and often commuted to work behind garbage trucks on their way to the Cedar Hills landfill. Bits of litter and trash continually accumulated along the sides of the road, she said.

However a contingent of Georgetown residents also attended the meeting. Many of them said Harbor Island was a better location for an intermodal solid waste transfer facility than their neighborhood.

"Fourteen hundred people live in Georgetown," one woman said. "We are not industrial, we are residential."

A preferred site is scheduled for selection next fall. Construction is planned to begin next year.

Tim St. Clair can be contacted at 932-0300 or tstclair@robinsonnews.com.