5109 SOUND AVE 2017-08-02 - Laserfiche WebLink

July 21, 2014 Two Single-Family residences L&A Job No. 14-065 Page 24 The infiltration trenches should be at least 24 inches wide. The side walls of the trenches sllould be lined with a layer of non-woven filter fabric, such as MIRAFI 140NS. The trenches are then filled with clean, 3/4 to 1-1/2 inch, washed gravel or crushed rock to within about 10 inches of the finish grade. The dispersion pipes should be constructed of 4-inch rigid PVC pipes and laid ]evel in the gravel or crushed rock filled trenches at about 16 inches below the top of trenches. The top of the gravel or crushed rock fill should also be covered with the filter fabric liner. The remaining trenches should then be backfilled with compacted onsite clean soils. The gravel or crushed rock fill should be placed in lifts no more than 10 inches thick in loose state, with each lift compacted to a non- yielding state with a vibratory mechanical compactor. The compaction and densification of trench fill is critical if it is to support driveways. Stormwater captured over paved driveways should be routed into a catch basin equipped with an oil-water separator before being released into the inf ltration trenches. RISK EVALUATION STATEMENT It is our opinion that if the recommendations in this report are fully implemented and observed during construction and following the completion of construction, the areas disturbed by construction will remain stable and will not increase the potential for soil movement. In our opinion, the risk for damages to the proposed development and from the development to adjacent properties from soil instability should be minimal. LIMITATIONS This report has been prepared for the specific application to this project for the exclusive use by Belmark, LLC, and its associates, representatives, consultants and contractors. We LIU & ASSOCIATES, INC.