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<br />COMPOST FACILITY STORM WATER IMPROVEMENTS 3-2 <br />repair defects. Tests will be performed on both the geomembrane and on the field-constructed seams. <br />A leak location test will be performed on the geomembrane following installation of the <br />geomembrane. CQA inspection and testing procedures are defined in the Specifications <br />(Appendix C) and in the CQA Manual (Appendix D). <br />A 3-ft deep pan lysimeter is located in the southwest corner of the retention basin and is lined with a <br />60-mil HDPE geomembrane and a GCL. Coarse Gravel encompassed in geotextile is placed within <br />the lysimeter. Access to the pan lysimeter is via an 18-inch dia HDPE perforated and non-perforated <br />riser pipe that extends to the crest of the retention basin. <br />Wind vents are incorporated into the retention basin slopes to prevent uplift of the liner system. The <br />wind vents are located on 5-ft centers and approximately 8-inches downslope from the retention basin <br />crest, within the 2-ft freeboard. The wind vents consist of a 1” dia hole cut into the HDPE <br />geomembrance. The hole is covered by a 1-ft square patch of HDPE geomembrane welded on the top <br />and bottom but open on the sides. <br />The retention basin lining system will be anchored beyond the crest of the basin using an earth-filled <br />anchor trench. The anchor trench consists of a 4-foot deep by 3-foot wide perimeter trench set back a <br />minimum of 5-ft from the crest of the retention basin slope. <br />Safety ladders are included at 50-ft intervals and are held securely within the anchor trenches using <br />No. 4 rebar. The safety ladders are composed of a 3-inch diameter UV protected nylon rope with <br />rungs spaced at 2-ft intervals. The safety ladders are held in place at the bottom by a gravel log <br />created by wrapping granular drainage material within a 16-oz nonwoven geotextile. The gravel logs <br />are continuous along the basin toe and, in addition to securing the safety ladders, provide ballast for <br />the lining system to aid in preventing uplift. An access ramp is also located along the north side of <br />the retention basin.