8920 EVERGREEN WAY THE RESERVE 2025-07-25

Zipper Geo Associates, LLC Reserve at Everett Project No.1117.01 May 1,2013 considered impermeable. As a result, it is our opinion that infiltration at the site is not feasible for this project. Site Preparation Erosion Control Measures: Stripped surfaces and soil stockpiles are typically a source of runoff sediments. We recommend that silt fences, berms, and/or swales be installed around the downslope side of stripped areas and stockpiles in order to capture runoff water and sediment. If earthwork occurs during wet weather, we recommend that all stripped surfaces be covered with straw to reduce runoff erosion,whereas soil stockpiles should be protected with anchored plastic sheeting. Temporary Drainage: Stripping, excavation, grading, and subgrade preparation should be performed in a manner and sequence that will provide drainage at all times and provide proper control of erosion. The site should be graded to prevent water from ponding in construction areas and/or flowing into and/or over excavations. Exposed grades should be crowned, sloped, and smooth-drum rolled at the end of each day to facilitate drainage if inclement weather is forecasted. Accumulated water must be removed from subgrades and work areas immediately and prior to performing further work in the area. Equipment access may be limited and the amount of soil rendered unfit for use as structural fill may be greatly increased if drainage efforts are not accomplished in a timely manner. Clearing and stripping: Based on conditions encountered in our borings,the majority of the site includes a surficial mantle of forest duff and topsoil on the order of 6 to 10 inches thick. However,in local areas the forest duff and topsoil was on the order of 1.5 to 2 feet thick. All forest duff and topsoil should be stripped and wasted off site. Existing concrete foundation elements and concrete and asphalt pavements should also be demolished and hauled off site. Undocumented Fill Removal: In some test pits, undocumented fill consisting of organic rich soils, concrete rubble and other undocumented fill was encountered. The thickness of undocumented fill soils observed in the test pits was a maximum of about 2.5 feet. In some areas,the undocumented fill may require removal and replacement. The need for removal of undocumented fill should be based on observations and recommendations by ZGA during construction. Subgrade Preparation: Once site preparation is complete,all areas that are at design subgrade elevation or areas that will receive new structural fill should be compacted to a firm and unyielding condition. Some moisture conditioning of subgrade soils may be required during construction to achieve a moisture content appropriate for compaction. We expect moisture conditioning consisting of drying will be required in areas where the weathered Glacial Till is exposed at subgrade elevation. Laboratory testing of weathered Glacial Till samples indicate moisture contents well above optimum moisture content for compaction. Page 7