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Teri Higgins June 30, 2016 Page 3 DOGAMI maps also provided an estimate of the PGD expected in a CSZ event. Once the ground liquefies, or a landslide is initiated, the ground will permanently displace, moving downhill, or towards a free face such as a river bank. The greater the PGD, the more pipeline damage is expected. 3.Overview of Seismic Vulnerability of Wastewater Systems Wastewater systems are vulnerable to earthquakes due to shaking and ground deformation. Structures such as pump stations, above grade piping, and treatment plants are vulnerable to seismic lateral loading. Heavy, cast in place reinforced concrete structures that make up many wastewater system components are resistant to lateral loading. Other types of structures such as tilt‐up buildings, concrete frame buildings, and unreinforced masonry buildings are vulnerable. The building code to which structures were designed is important. In Oregon, the Zone designation in the Uniform Building Code (UBC) that was in place in the early 1990s, was increased from Zone 2 to Zone 3 as seismologists gained a better understanding of regional seismicity. Buildings designed earlier are more vulnerable to earthquakes. Buildings designed to modern earthquake codes should perform much better in a CSZ event. When the building shakes, inadequately supported piping and conduits can swing and break off at hard points, wall penetrations and connections to pumps and other equipment. Heavy inline equipment such as check valves add additional loading to the pipelines exacerbating the situation. Steel and ductile pipe will perform better than brittle cast iron. Broken pipelines can result in flooding particularly in below grade structures. Regional power is often disrupted. High voltage substation equipment is the most seismically vulnerable part of a power system with their tall fragile ceramic insulators. Substation rigid busses and switch gear is also fragile. Within facilities, inadequately anchored electrical cabinets can tip over, breaking off connections and damaging internal equipment. In addition to shaking, liquefaction and associated lateral spreading can be devastating to the wastewater facilities. Wastewater facilities are often sited in low areas where it is likely to be more liquefiable. The Higashinada Treatment Plant in Kobe Japan was founded on liquefiable soil. In the 1995 Kobe Earthquake, the plant site settled up to one meter and moved laterally two meters causing extreme damage. If liquefaction occurs below or around a building such as a pump station, it can float or tip severing connecting pipelines as occurred to several pump stations in the 2011 Christchurch New Zealand event. Even if everything within the pump station remains intact, the sewage cannot flow in or get pumped out. In some cases, the opening left from these severed pipe connections allowed liquefied sand to enter the pump station. Cleanup of liquefied sand in wastewater pump stations was an issue in Seattle following the 2001 Nisqually Earthquake. Pipelines are potentially more vulnerable than structures. Ground shaking can cause adjacent pipe segments to move relative to one another damaging rigid joints. Joints that are mortared can crack. 2020 Eugene Wastewater Master Plan Appendix A-3