2014/05/28 Council Agenda Packet

Executive Summary Each year, landslides along the Pacific Northwest Rail Corridor interrupt rail service for passenger and freight trains. High numbers of landslides between Seattle and Everett have been especially problematic for Sound Transit commuters and Amtrak Cascades passengers. Record numbers of service interruptions (sum of annulments and disruptions for all passenger trains) during the 2012-2013 winter season prompted collaboration among Washington State Department of Transportation (WSDOT), BNSF Railway Company, Sound Transit, Amtrak, and stakeholders to quantify the landslide -related impacts, identify the primary factors within the corridor that contribute to landslides, and develop mitigation strategies to reduce the occurrence and impact of landslides. WSDOT created the Landslide Mitigation Work Group and convened bi-weekly meetings over a nine -month period. The mission of the Work Group was to develop short- and long-term strategies to reduce landslide impacts and improve transportation reliability throughout the corridor. Documented landslide impacts for Sound Transit commuters and Amtrak passengers include direct costs, such as annulments (cancelation of trains), busing customers around the closure area, loss of ridership; and costs to BNSF for landslide debris cleanup. Indirect costs are also substantial but harder to quantify, and may include declining ridership due to perceived unreliability of winter service, devaluation of property values and subsequent loss of tax revenue, loss of commercial productivity, and increased congestion on roads when rail service is interrupted. The majority of landslides that impact the rail line are shallow in depth and are sensitive to well - established factors and conditions. These factors include heavy or prolonged precipitation during the rainy season; the steep, high slopes that are prevalent along the corridor; underlying geology frequently associated with shallow landslides; and poor slope management practices carried out by adjacent landowners, such as discharging stormwater above or on steep slopes and disposing of yard, construction and earthen debris onto slopes. Commonly, it is a combination of factors that converge to start landslides. Potential strategies to reduce landslide interruptions and impacts were explored by the Work Group. Strategies were outlined and evaluated for implementation time, complicating factors, and short, moderate-, and long-term effectiveness to reduce or prevent landslides. The Work Group recognizes that measurable long-term reduction in landslide -related impacts to passenger service will require substantial investments in capital improvement projects. Depending on the financial resources available, as well as factors such as permitting, design, and construction scheduling, the time required to achieve significant reductions in landslide -related service interruptions will likely take one or more decades.