4704 HARBOR LN 2018-01-02 MF Import

Final Summary Letter Anderson Slope Stabilization Everett, Washington NGA File No. 816909 May 14, 2010 Page 4 CURRENT COND►PONS All of the restoration work on your property and on Lot 49 associated with the landslide and tree removal has been completed. The soldier pile wall was installed successfully near the top of the northwest -facing slope. Erosion control malting was placed on the exposed soil below the wall, including in the area of the landslide. As part of slope restoration, the trees that had previously been cut down and left on the slope were removed from your property and Lot 49. After the trees were removed, landscaping plant% were planted on the slope, as approved by the City of Everett. To improve site drainage, all of the downspouts and yard drains were rc-routed to a central catch basin above the wall, and then tightlined to the bottom of the slope, as described in the Site Evaluation and Slide Repairs subsection of this letter. Also, the pool decking that was damaged during the installation of the soldier pile wall has been repaired, and vegetation has been planted in the designated NGPA area above the wall. A fence will be installed soon for safety due to the extreme height of the wall. OUTSTANDING ISSUES As part of the original City requirements, downed trees were to be removal from the Chris Chase property (Lot 48), minor regrading of the landslide material on this lot was to take place, and vegetation was to be re -planted in the areas that were disturbed by the landslide. We understand that this neighbor has not granted you access to his property to carry out the repairs, though numerous attempts have been trade and restoration repairs have been submitted to him. That being said, currently the landslide debris on I.ot 48 is covered with abundant natural vegetation. The area is currently stable, and it is our opinion, from a gcolechnical standpoint, that no further actions need to be taken. CONCLUSIONS It is our opinion that the site is stable with respect to large-scale slope instability and the house is well protected. Basal on our observations and subsurface explorations, it is our opinion that the drainage improvements and the installation of the soldier pile wall, along with erosion control measures and mitigation of the slope below the wall, have drastically increased the stability of the hillside. NELSON GEOTECNNICAL ASSOCIATES, INC.