Resolution No. 4814 - Laserfiche WebLink

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In addition to direct landslide damages within the Eugene/Springfield Metro Area, the area is subject to the economic impacts of road closures due to landslides, which disrupt access/egress to/from the Eugene/Springfield Metro Area. Landslide induced road closures affecting the Eugene/Springfield Metro Area are possible in or near the Eugene/Springfield Metro Area in the high hazard areas shown on the maps, as well as further away on highways into the Cascades or through the Coast Range. The February 1996 winter storms provided numerous examples of landslide damages, especially to the road system, with landslides and mudslides closing many roads in Lane County and other nearby counties. The potential impacts of landslides and debris flows on the Eugene/Springfield Metro Area are summarized below in Table 8.6. Table 8,6 Potential Impacts of Landslides and Debris Flows on the Eugene/Springfield Metro Area Inventory Probable Impacts Portion of Eugene/Springfield Metro Landslides are hkely to directly affect only limited portions of Area affected Eugene/Spnngfleld Metro Area as shown above on Maps 3E, 3S, 4E and 4S. Medium and high landslide potenbal areas are residential, Small Buildings landslides are likely to affect no buildings or only 1 or 2 buddings, Larger landslides could affect several buildings Minor road closures possible from landslides; limited impact Streets within Metro Area because of short detour routes within Eugene/Spnngfield Metro Area Potential closures of major h~ghways due to lands~des, especially Roads to/from Metro Area roads into the Cascades and Coast Range, Potential for localized loss of etectdc power due to landslides Electric power affecting power hnes in or near Eugene/Springfield Metro Area Potential minor outages of water, wastewater and natural gas Other Utilities from pipe breaks from landslides, Probable ~mpacts would generally be very localized. Landslides that impact buildings or roads could result Jn a small Casualties number of casualbes (deaths and Jniunes) 8.4 Mitigation of Landslide Risk Mitigation of landslide risks is often quite expensive. In some cases, slope stability can be improved by addition of drainage to reduce pore water pressure, by construction of appropriate retaining walls or by other types of geotechnical remediation. In some cases, buildings can be hardened to reduce damages. An alternative mitigation strategy for existing buildings or infrastructure with high potential for landslide losses is to relocate the facilities outside of known slide areas. Mitigation of landslide risk can also be accomplished by effective land use planning to minimize development in slide-prone areas. Generally, such land use planning requires rather detailed geotechnical mapping of slide potential so that high hazard areas can be demarcated without unnecessarily including other areas of Iow slide potential. Public Review Draft: August 6, 2004 8~10