1215 MADRONA AVE 2016-08-24 - Laserfiche WebLink

1 ' ' 1 1 ' Gustafson Residence Retaining Wall NGA File No 924115 1215 Madrona Avenue June 12, 2015 Everett, Washington Page 11 following vegetation: Snowberry (Syinphoricarpos albus), Nootka rose (Rosa nutkana), Ocean Spray (Holodiscus discolor), and Oregon-grape (Manhonia nervosa). We should be retained to review and comment on the slope vegetation plan and observe the slope repairs. USE OF THIS LETTER NGA has prepared this letter for Dennis and Kathy Gustafson, and their agents, for use in the planning and design of the retaining wall project on tl�is site only. This ]etter is a specific evaluation of the existing timber retaining wall and steep slopes and should not be considered an evaluation of the entire site or the existing residence. There is potential for failures to continue to occur on the slope near and below the � wall. This potential can be reduced by maintaining the drainage systeins and refraining from casting any material what so ever over the slope. Irrigation systems near the new wall should be avoided. The scope ' of our work does not include services related to construction safety precautions, and our recoinmendations are not intended to direct the contractors' methods, techniques, sequences, or procedures, except as ' specifically described in our letter for consideration in design. There are possible variations in subsurface conditions between the explored and unexplored areas and also with time. Our letter, conclusions, and ' interpretations should not be construed as a warranty of subsurface conditions. A contingency for unanticipated conditions should be included in the budget and scl�edule. 1 ' 1 ' ' 1 ' 1 ' All people who own or occupy homes on hillsides should realize that landslide movements are always a possibility. The homeowner should periodically inspect the slope, especially after a winter storm. If distress is evident, a geotechnical engineer should be contacted for advice on remedial/preventative measures. The probability that landsliding will occur is substantially reduced by the proper maintenance of drainage control ineasures at the site (the runoff from the roofs should be led to an approved discharge point). Therefore, the homeowner should take responsibility for performing such maintenance. Consequently, we recommend that a copy of our letter be provided to any future homeowners of the property if the home is sold. We recommend that NGA be retained to review project plans prior to construction and to monitor wall repairs. These additional services are intended to confrm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate wliether or not NELSON GEOTECHNICAL ASSOCIATES, INC.