1209 MADRONA AVE 2016-11-17 - Laserfiche WebLink

Geotechni�al Engineering Evaluatian Packer Property Retaining Walis and Steep Slo�e Evaluatian Everett, Waslltngton ��Ti2�BUCTI�N This report presents the results of our geotechnical engineering investigation and evaluation of the existing block retaining walls and steep slopes at the Packer property in Everett, 'l�%ashington. The project site is located at 1209 Madrona .qvenue, as sho«�n on the Vicinity Map in Figure 1. The purpose of this study is to explore and c}iaracterize the site's surface and subsurface conditions, and to provide geotechnical recammendations for improving the conditions of the existing walls and stabilization of the landslide that recently occuired on the steep slopes withiu the nortllern portion of the property. The property is currently occupied by a single-fainily residence within the southern portion of the site. A steep north�rest-facing slope is located to the north of the residenee. The portion of the steep slope alon� the c��estern property liiie appears to be an old ravzne area. The neighbaring property to the west sIopes steeply down to your western property line and appears to share the steep slope area vvithin the old rairine. There is a total of five tiers of short concrete block walls existing on the steep slope below the residence. We understand that the property owner began constrncting the lower u�estern block wall along the steep slope immediately above the old ravine area in the sum�ner of 2000. Tl�e upper three walls were then constructed during 2001 to 2003. The lower eastern wall was then constructed in 2005 after a landslide occurred below the lower western wall. In general, these walis appear to be relatively stable and appear ta have experienced minimal moveznent throughout the years since they were constructed. We also unde;.stand that in Iate Novetnber 2012, two landslides occurred over a 24 haur period. The first slide involved the lower (down-ravine} portion of t}�e steep neighboring slope to the west and an area on the Packer propert}� directly adjacent to #he neighbor's landslide area, but iower in elevation. The slide area an the Packer property extended up-ravine to about fifteen feet beiow the lower v��estern retaining wa11. The second slide invoived the upper (fiirther up ihe ravine} portion of the steep neighboring slope to the west. A1so involved was an area of the Packer property directly adjacent to the neighbor's new tandslide area, but lower in elevation. The new slide area on the Packer property becam.e within five feet belo�� the lower western retaining wall. Prior vegetation that was planted on the slope by the homeowners were m.ostiy removed by the recent slides. MELSOIV GEC?TECHNICAL ASSOCIATES, lR��.