Soil depth of 20 to 40 inches <br />Slopes of 30 percent and above <br />5. Eugene Formation <br />Soil depth of 20 inches to 40 inches <br />Slopes of 30 percent and above <br />The applicant has provided a geotechnical/geologic investigation (dated February 6, 2017) and <br />subsequent addendum (dated May 30, 2017), which included field observations, subsurface <br />explorations, and data analyses confirming the site contains Eugene Formation sandstone and <br />siltstone formation with soil depths exceeding 40 inches and slopes exceeding 30 percent, <br />consistent with conditions #1 and #5 listed above, requiring both on-site and off-site review of <br />impact. <br />Offsite review of impact included a Geotechnical Engineer's inspection of the surrounding area <br />to map geological surface features. Offsite landslide forms were mapped in the existing <br />residential areas. According to the engineer of record, "The primary area proposed for <br />development in the Capital Hill PUD is the only area on this hill that is outside of mapped <br />landslide hazard areas." Onsite review included the aforementioned subsurface explorations <br />conducted by Branch Engineering with ten (10) exploratory test pits and surface reconnaissance <br />of the site. This on-site review determined the majority of the development site is underlain by <br />stable volcanic rock material. <br />The off-site and on-site proposed improvements include shallow widening of Capital Drive <br />fronting the site, mostly occurring in up-hill cut conditions, and relatively shallow utility <br />construction in existing paved roadways. Other improvements include construction of a private <br />road along a former cleared and graded vehicle accessway, and grading associated with <br />stormwater facilities. The mass movement of earth materials is not expected and there is a <br />relatively low risk of off-site impacts due to the proposed development. <br />The geotechnical/geologic investigation found no significant geologic hazards that would <br />impede or restrict the construction on the site. The investigation does acknowledge that <br />shallow slide debris in the top 2.5 feet of ground material can be expected in the steeper lots. <br />The map included with the May 30, 2017 Geotechnical Addendum identifies the steepest areas <br />along the eastern portion of the site as "High - Landsliding Likely," affecting Lot 5, Lots 8 <br />through 20, and Lot 33. The geotechnical/geologic investigation also found that the site is <br />geologically and geotechnically suitable for the proposed development, provided that specific <br />recommendations described in the investigation are incorporated into the design and <br />construction of the project. Additional discussion of the geotechnical issues and Eugene Code <br />requirements are found at EC 9.8320(6) and EC 9.6710 Geological and Geotechnical Analysis, <br />later in this report. A condition of approval is recommended at EC 9.8320(6) to ensure the <br />recommendations of the applicant's geotechnical/geologic investigation are carried out during <br />future development of the site. <br />Based on the available information and findings above, and with the condition of approval as <br />recommended at EC 9.8320(6) of this report, staff concludes that the PUD is consistent with <br />the applicable policy language. <br />Capital Hill PUD (PDT 17-1) February 2018 11 <br />Page 11 <br />