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Earth Engineering Consultants,LLC <br /> EEC Project No.1212092 <br /> November 23,2021 <br /> Page 4 <br /> Groundwater <br /> Observations were made while drilling and after completion of borings to detect the presence and <br /> depth to groundwater.During drilling operations, groundwater was encountered at depths ranging <br /> from approximately 5.5 to 7 feet below ground surface. Approximately 2 weeks after drilling, <br /> groundwater was measured at depths ranging from approximately 5.3 to 6.3 feet below ground <br /> surface. After the last groundwater level measurement, the piezometers were removed, and the <br /> boreholes were backfilled. <br /> Fluctuations in groundwater levels can occur over time depending on variations in hydrologic <br /> conditions(i.e.,the water levels in the South Platte River)and other conditions not apparent at the <br /> time of this report.Long-term monitoring of water levels in cased wells,which are sealed from the <br /> influence of surface water,would be required to evaluate the depth and fluctuations in groundwater <br /> levels at the site. <br /> Physical Characteristics of Subarades <br /> The site subgrades encountered generally consisted of a relatively thin mantle of near surface <br /> cohesive overburden soils underlain by sand with gravel with various amounts of silt and apparent <br /> cobbles with depth. The physical properties of the materials encountered in the borings are <br /> summarized in the following sections.Note that changes in materials and physical properties of <br /> those materials may vary from boring location to boring location. The parameters outlined below <br /> do not include any safety factors. <br /> Overburden <br /> The overburden subgrades generally consisted of sandy clay and clayey sand. Laboratory testing <br /> on select samples of the overburden soils included Atterberg limits, washed sieve analysis, and <br /> unconfined compression(estimated using a calibrated hand penetrometer)tests. The results of the <br /> laboratory testing are included on the attached boring logs and summary sheets. <br /> In summary, the overburden soils were low to moderately plastic with liquid limits ranging from <br /> 27 to 37%with plastic indices ranging from 10 to 20%.At current moisture and density conditions, <br /> the subgrades were relatively stiff to very stiff. <br />