Every time mud flows onto the rail tracks between Everett and Seattle, Washington, commuter lines are shut down for days. The State of Washington and other stakeholders are implementing a multipronged plan to reduce the number of such flows. Courtesy of the Washington Department of Transportation
Each time a mudflow covers the train tracks in western Washington, commuter trains are sidelined for 48 hours. After a record-breaking rainy winter, state and local governments, as well as rail operators, have identified six areas in need of improvement.
July 2, 2013—Everyone’s morning commute has its headaches. Coffee spills on a white shirt, or a fender bender backs up a two-lane road for miles. But in the area north of Seattle, commuters who look to use the Sounder train service often face a more daunting hurdle: mudflows that can close the tracks for two days at a time.
And in a region known for its wet weather, the flows are all too regular an occurrence, turning those occasional commuter headaches into migraines. So the Washington State Department of Transportation, BNSF Railway Company, based in Fort Worth, Texas, and the communities perched on the slopes above the 30 mi segment of track between Everett and Seattle are looking into ways to prevent and mitigate the flows.
A total of 200 flows were reported during the winter of 2012–13, according to BNSF spokesman Gus Melonas, and 82 of them were considered “significant.” Of the significant flows, 50 came into contact with the rails, prompting a mandated 48-hour shutdown of passenger trains. “As far as continuous, day-after-day, this [was] in the top four [rainiest winters] that I recall in my 38-year career,” says Melonas.
BSSF controls 300 mi of track between Portland, Oregon, and Vancouver, British Columbia, but this particular stretch is also used by Amtrak and Sound Transit, which operates the Sounder trains. Together, these parties are studying ways to limit mudflows between Ballard, a community just north of Seattle, and Everett, which is about 25 mi away, and have demarcated six locations that need work. Initial efforts will be focused on a sensitive segment of the railway covering about 6 mi between Mukilteo and Everett.
According to David Smelser, the state’s program manager for high-speed rail projects, one project has already received environmental clearance, and approval for a second is expected soon. Funding comes from a $16.1-million federal grant, and if both locations receive attention this summer, commuters may see a substantial reduction in problems this winter. “Part of the difficulty is that there are dozens of areas that have slid over the last two years,” Smelser says. “Here we’re looking at what are the highest-impact ones, and the ones that are causing us the most disruption.” Work on the remaining four zones will begin sometime in 2014.
Factors ranging from the way storm water is diverted to how homeowners dispose of such yard debris as lawn clippings can influence the winter mudflows, but the key trigger of instability seems to be consistent, saturating rains. According to Melonas, during the first part of last winter, that is, before December 24, the area saw 68 days of significant rainfall. “We’ve had much more debris coming down than in past years,” says Melonas. With “day after day of rainfall,” flows are inevitable, he says, and “we’re caught at the bottom.”
Ryan Sass, P.E., the City of Everett’s engineer, agrees. “It has more to do with long periods of lower-intensity rainfall, [in which] the saturation is gradually increased, than high rainfall events,” he says. Sass notes that his office receives reports of flows almost daily each winter. “All of our slopes are marginally stable and in a situation where they’ve been moving for a very long time, and they will continue to move,” he explains.
Cliff Mass, a professor of atmospheric sciences at the University of Washington, backs up Melonas’s claims on his weather blog, showing that the area around Everett received more rainfall than was normal late in 2012. And although his predictions for this coming winter are not so dire, the goal is to limit the flows over the long term so that the commuter trains—four southbound each morning and four northbound each afternoon—can operate without major incidents by 2017. Commuters, says Smelser, “need to know the train is running every day when they drive up to the station; they need to be at work on time,” and he points out that Sounder customers lose confidence every time a slide affects their commute. “It’s become incumbent upon us to figure out how to service a new [customer] base, and part of that is . . . a guarantee we’ll get you there on time.”
Smelser says that there are three elements to the planned work. “One of them is removing existing slide debris—material that’s on the slope. Second is installing underdrains to help dewater the slope—finger drains, that sort of thing.” Third, he says, will be installing catchment basins at the base of the hills beside the tracks.
Melonas and Smelser both say that the plan will also include clearing the railway’s right-of-way when the line is not in use, enhancing the capabilities of existing sensors that detect flows, and talking to the residents who live on the bluff about how their actions affect the slope. “A lot of folks throw the trimmings from their yard over the slope, and when you put that decaying vegetative matter over the slope, it gets heavy and has a destabilizing effect and can actually be part of a trigger for a slide,” Smelser says. Composting clippings, he says, would help matters, but care is required: “It’s a great idea, but don’t do it over the edge of the slope,” he says. Roof drains that flow into backyards can also end up sending more water down the slopes, he adds. “There are other ways to handle that water,” he says. “Those are the kinds of things people don’t necessarily think about.”
So a coordinated strategy that involves the cities, the state, the railway, and homeowners is important. “There is a lot of great material for property owners out there, but it’s in all different places,” Smelser says. “So we’re putting together a brochure and putting on workshops and making those available for all the local agencies.”
Meanwhile, Sass says, “we’re looking at the top of the slopes, [making] sure there’s nothing from the municipal side that’s contributing.” The City of Everett is adding meters to its last remaining segments of unmetered water lines to keep an eye out for long-term leaks that can also add to instability, he says.
The problem could recur this winter, Smelser says, although he adds, “If we have a record dry winter, we probably won’t have these slides.” But as a hedge he wants to see the first two segments of the state-run project completed in 2013. “We can only control so many factors,” he says. “But we’ve identified these as the areas that will give us the best results for the effort.”