Geotechnical Soil Infiltration Investigation <br />2610 Cal Young Road, Eugene, Oregon <br /> <br />1 | P a g e CORE GeoEngineering, Inc. Project No. 25-1127 <br /> Version 1.0, January 23, 2026 <br /> <br />1.0 EXECUTIVE SUMMARY <br />CORE GeoEngineering was retained by KJH Exchange LLC to conduct a geotechnical soil infiltration <br />investigation at 2610 Cal Young Road in Eugene, Oregon (Lane County Tax Lot 1703204101300). The <br />purpose of this investigation was to evaluate subsurface soil conditions and determine in-situ infiltration <br />rates to support the design of stormwater management systems for a proposed residential development. <br /> <br />Site Conditions <br />The 1.42-acre property is relatively level to gently sloping and contains an existing residence. Subsurface <br />exploration consisted of five test pits excavated to depths ranging from 5.5 to 8 feet below ground surface. <br />Soils encountered consisted primarily of Lean CLAY (CL) and Lean CLAY with Gravel (CL). No groundwater <br />seepage was observed during our exploration, which was conducted on December 5, 2025. <br /> <br />Infiltration Testing Results <br />Six infiltration tests were performed using the open-pit falling-head method in accordance with the City <br />of Eugene Stormwater Management Manual. All tests indicated zero measurable infiltration capacity at <br />the tested locations and depths. The clay soils encountered exhibit very slow permeability and do not <br />appear to be suitable for conventional stormwater infiltration systems at the depths evaluated (3 to 8 feet <br />below ground surface). <br /> <br />Conclusions and Recommendations <br />Based on the observed soil conditions and infiltration test results, stormwater infiltration systems do not <br />appear to be geotechnically feasible within the clay soils present at shallow depths across the property. <br />Historical well logs from the site vicinity indicate that coarser-grained gravel deposits may be present at <br />greater depths which could potentially provide improved infiltration capacity. However, the presence, <br />depth, extent, and infiltration characteristics of these deeper deposits would need to be confirmed <br />through deeper exploratory borings and additional testing. <br /> <br />Alternative stormwater management approaches may be considered for this development, such as <br />detention systems with controlled discharge, connection to municipal storm systems, or deeper <br />infiltration systems if further investigation confirms the presence of permeable strata at depth. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br />