406 PECKS DR Geotech Report 2025-07-14

December 30th, 2021 G-5593 4730— Seahurst Ave,Washington 98203 Page 2 property line. The site is typically landscaped with grass groundcover,however, features some shrubs and trees. The slopes to the west are well vegetated with native trees, shrubs, and other groundcover. • The site is accessed by Seahurst Avenue to the east. A paved driveway extending from avenue enters the property at the northeast corner. The end of the driveway transitions to gravel material and is unpaved. The site is bounded by residential developed properties to the north, south, and east, and by undeveloped land to the west. Proposed Development At this time, we understand that the proposed development is comprised of a garage addition to be added to the south face of the residence as well as a new driveway. • SITE INVESTIGATION Geologic Overview According to the area geologic map,the site soils are identified as Vashon subglacial till (Qvt) from the Fraser Glaciation. Glacial till is described as a very compact mixture of sand, silt, clay, and gravel deposited under glacial ice during the Fraser glaciation period. Glacial till typically has a weathered zone of loose to medium dense soil on top, underlain by dense,unweathered till. Subsurface Investigation On December 8th, 2021, Garrett Dean, Staff Engineering Geologist from our firm, visited the site to perform a visual reconnaissance of the site and investigate the subsurface soil conditions. In addition to our reconnaissance, we completed three hand auger borings in the proposed project area at the site (HA-1 through HA-3). The boring locations are illustrated on the Existing Site Plan, and Proposed Site Plan, attached as Plates 2 and 3 to this report. The native soils encountered in the borings typically consisted of a thin surface veneer of organic-rich silty sand topsoil,underlain by medium dense to very dense silty sand with some gravel to the total depth of the borings, approximately 3 feet below the ground surface (bgs) in HA-2, and 3.3 feet bgs in HA-3. Soils encountered in HA-1 consisted of crushed rock fill material. The material was observed to be compacted to a very dense condition. Auger refusal GEO Group Northwest,Inc.