2000 TOWER ST INDEX HALL 2023-12-29

i&l •E ENGINEERING Temporary Drainage We recommend intercepting and diverting any potential sources of surface or near surface water within the construction zones before stripping begins. Because the selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the time of construction. Nonetheless, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept surface water runoff. Erosion Control Measures Because stripped surfaces and soil stockpiles are typically a source of runoff sediments, they should be given particular attention. If earthwork occurs during wet weather, we recommend all stripped surfaces be covered with straw to reduce runoff erosion. Similarly, soil stockpiles and cut slopes should be covered with plastic sheeting for erosion protection. We also recommend a staked silt fence be installed around the area to be disturbed. The base of the silt fence should be buried so that sediment cannot pass beneath it, and the silt fence should be inspected and maintained during the time that the site soils are exposed, on a periodic basis, and after any major rainstorm event. It may be prudent to maintain a berm and Swale around the downslope side of stripped areas and stockpiles to capture runoff water, thereby reducing the downslope sediment transport. In addition, the stripped areas should be revegetated as soon as possible, also reducing the potential for erosion. Clearing and Stripping After surface and near -surface water sources have been controlled, the construction areas should be cleared and stripped of all trees, bushes, sod, organic soils, and debris. It should be realized that if the stripping operation proceeds during wet weather, a generally greater stripping depth might be necessary to remove disturbed moisture -sensitive soils; therefore, stripping is best performed during a period of dry weather. Subgrade Compaction Exposed subgrades for footings, floors, pavements, and other structures should be compacted to a firm, unyielding state before concrete elements or fill soils are placed. Any localized zones of loose soils observed within a subgrade should be compacted to a dense condition. In contrast, any organic, soft, or pumping soils observed within a subgrade should be over -excavated and replaced with a suitable structural fill material. Reuse of On -site Soils Most of the on -site soils are highly moisture -sensitive and susceptible to disturbance when wet. We do not recommend reusing the native soils as structural fill. If it is planned to use the native soil in non- structural areas, the excavated soil should be stockpiled and protected with plastic sheeting to prevent it from becoming saturated by precipitation or runoff. MP ENGINEERING, PLLC MPGEOTECH.COM 8