Geotechnical Soil Infiltration Investigation <br />2610 Cal Young Road, Eugene, Oregon <br /> <br />2 | P a g e CORE GeoEngineering, Inc. Project No. 25-1127 <br /> Version 1.0, January 23, 2026 <br /> <br />2.0 PROJECT INFORMATION <br />This report presents the findings and conclusions of a soil infiltration investigation conducted by Core <br />GeoEngineering, LLC (CORE) for the referenced project. The purpose of the study was to assess subsurface <br />conditions and obtain measurements of in situ soil infiltration rates to support potential design of <br />stormwater management systems at the property. The investigation was performed in accordance with <br />Proposal No. P25-1085, dated December 2, 2025, and subsequent approvals of our proposal and General <br />Terms and Conditions. <br /> <br />3.0 SITE AND PROJECT DESCRIPTION <br />As indicated on Figures 1 and 2 the subject site is located at 2610 Cal Young Road in Eugene, Oregon, and <br />consists of Lane County Parcel No. 1703204101300, encompassing approximately 1.42 acres. The site is <br />bordered by Cal Young Road to the north, by an existing residential home to the west, by commercial <br />properties to the east, and by residential apartments to the south. The property contains an existing <br />residential home located in the west-central portion accessed via a gravel drive. Vegetation at the <br />property consists of grasses and trees in the north and is overgrown with blackberries, shrubs, and trees <br />to the south of the home. Topography is relatively level to gently sloping north with elevations ranging <br />from approximately 425 to 427 feet AMSL. The property is located in the NE ¼ SE ¼ of Section 20, T17S, <br />R3W, Willamette Meridian. The site latitude and longitude are 44.076586, -123.070811. The regulatory <br />jurisdictional agency is the City of Eugene, Oregon. <br /> <br />Through discussion with the project civil engineer, CORE understands that the proposed project will <br />involve residential development of the property. Stormwater infiltration systems are proposed to manage <br />runoff from new impervious surfaces. To support design of the systems, soil infiltration testing is needed <br />to determine infiltration rates and evaluate subsurface conditions. The Client, in coordination with the <br />project civil engineer, selected five test pit locations based on the potential planned locations of the <br />proposed stormwater infiltration facility and excavated to depths of approximately 5.5 to 8 feet below <br />existing grade to expose subsurface soils at the anticipated depth of the infiltration systems. Infiltration <br />testing was conducted within each test pit. <br /> <br />4.0 REGIONAL GEOLOGIC SETTING <br />The property is located within the southern portion of the Willamette Valley, a broad structural and <br />depositional basin bounded by the Coast Range to the west and the Western Cascades to the east. The <br />regional geology consists primarily of Quaternary alluvial and fluvial deposits derived from the Willamette <br />and McKenzie Rivers, composed of unconsolidated sand, gravel, silt, and clay deposited in channel, <br />overbank, and floodplain environments. These surficial sediments typically overlie Tertiary volcanic and <br />sedimentary rocks associated with the Western Cascades and marine sequences of the Coast Range. The <br />region’s geologic framework reflects the long-term influence of Cascadia Subduction Zone tectonics, <br />which have produced broad uplift, folding, and associated earthquake hazards. Additionally, Pleistocene <br />glacial outwash, episodic flooding, and volcanic input have contributed to the heterogeneous character <br />and variable engineering properties of near-surface soils throughout the Eugene area.