4704 HARBOR LN 2018-01-02 MF Import

r IGeotechnical Engineering Evaluation Anderson Landslide Repairs 4704 Harbor Lane Everett, Washington INTRODUCTION This report presents the results of our geotechnical engineering investigation and evaluation of the landslide that occurred at the Anderson property in Everett, Washington. The project site is located nt 4704 harbor Lane, as shown on the Vicinity Map in Figure I. The Tax parcel numbers for the property are listed as 00417100000802 and 00417100000900. For our use in preparing this report, we were provided with a topographical site plan titled "Anderson Slide Topographic Survey;' prepared by llarntsen & Associates, Inc, dated September 3, 2009. We were also provided with a letter prepared by the City of Everett — Planning and Community Development titled "Tree Cutting near Merrill & Ring Creek." dated Juh, 17. 2009. The residence is situated on gently sloping ground above a steep northwest -facing slope overlooking Merrill & Ring Creek. The single-family residence has a daylight basement, with an outdoor swimming pool and small jacuzzi located between the residence and the top of the steep slope. An area of the upper portion of the slope downslope trom the residence recently experienced major slope movement. An exposed scarp has tonucd directly below the top of the slope along the middle portion of the slope. We understand that a significant water leak occurred on the front side of the residence shortly prior to the observance of the landslide. Evidence of settlement and subsidence was observed at the top of the slope and in the vicinity of the swinuning pool. We also understand that some trees were removed from the slope below the residence and on neighboring property a few weeks prior to the slide. The existing site topography is shown on the Site Plan in Figure 2. For the purpose of this study, the site slope will be considered to be north facing. The letter from the City of Everett summarized short- and long-term measures that they required due to the tree removal. For the short term, the City of Everett requested a plan for restoring the trees that had been cut, as well as for erosion control and maintenance, and a report from a geotechnical engineer regarding the stability of the slope. For the long term, the City indicated that the slope/critical area must be restored per an approved restoration plan, with respect to city codes and regulations, and that the recommendations from the geotechnical engineer should be followed, as approved by the City. 7