2014/05/28 Council Agenda Packet

Proactive responses, on the other hand, require considerable planning, especially when having to choose among hundreds of landslide -prone slopes. Some of the benefits of a proactive response generally include lower costs, better conditions to design and build under, and higher reliability. With the responsibility of managing many unstable slopes along transportation facilities, several public transportation departments (including WSDOT) instituted management systems for proactively identifying, prioritizing, programming, funding and ultimately mitigating these hazards. It is important to stress that implementation of a proactive management system to address large numbers of landslide -prone slopes does not relieve the need for reactive responses or eliminate the potential of further closures. When managing numerous unstable slopes, it is not possible to predict which slope will fail first or when it will fail. In addition, program implementation requires long-term commitments, since it can take many years to make necessary improvements to significantly reduce landslide -related closures on such a landslide -prone corridor. As an example, in 1974 a rock slope maintenance program was implemented along a rail corridor in British Columbia involving 750 rock fall sites. In the opinion of the geotechnical specialist involved since program inception, it took nearly three decades for the program benefits to become clearly recognizable (WSDOT, 2006). p. 20