J_2024 05 09_West Orange Stormwater Management Plan

August 8, 2022 File No. 26.0092704.00 PSE&G – West Orange, NJ Page 6 Proactive by Design 1) Surface Materials: A layer of crushed stone on the order of 10 to 12 inches in thickness was encountered at test boring SBH-1 and SBH-2. At the remaining three explorations, 8 to 11 inches of topsoil was encountered. The test pits were all performed within the lawn areas and encountered 6 to 20 inches of topsoil at the ground surface. 2) Fill: The surface materials were underlain by clayey silt and silty sand fill in the borings which extended to depths on the order of 2.5 feet to 8 feet below the existing surface grades. Fill and possible fill was also encountered in the three test pits and extended the full depth explored in the test pits. A layer of buried topsoil was encountered at the base of the fill in SBH-2, SBH-3, and SBH-5. 3) Clayey Silts and Silty Clays: The surface materials, fill and buried topsoil, where present were underlain by stiff clayey silts and silty clays. The silts and clays typically extended to depths of about 15 to 24 feet below the ground surface in the explorations to the underlying weathered basalt bedrock except for SBH-3 and SBH-4. 4) Clayey Sands: The silts and clays in SBH-3 and SBH-4 were generally underlain by medium dense to very dense clayey or silty sands at about 15 feet below the ground surface The clayey sands extending to depths ranging from about 25 to 28 feet below grade. Gravel, cobbles, boulders or weathered rock were encountered in the deeper portions of this layer and may represent weathered bedrock. 5) Decomposed and Weathered Basalt Bedrock: The clayey sands and/or clays and silts were typically underlain by decomposed/weathered and fractured basalt bedrock. Groundwater seepage was encountered in the three test pits at depths ranging from 4 to 9 feet below the ground surface. Groundwater levels were not recorded in the soil borings as the borings used rotary wash techniques which use water to facilitate the drilling, however, water levels were estimated to be between 10 to 15 feet in the borings based on review of the soil samples. Groundwater was also encountered at 7 feet below the ground surface in a prior boring (SBH-5) from our 2011 sutyd, and is also shown on the Plot Plan. Groundwater seepage conditions should be expected to vary seasonally. An Equal Opportunity Employer M/F/V/H