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Wastewater Treatment System NOW FALL CREEK Specifications ENGINEERING,INC. The inlet lateral pipe shall have ''/2" orifices on one-foot centers. The orifice holes shall face downward toward the riprap at approximately 135° from vertical. The outlet lateral shall be a perforated pipe that allows a maximum amount of flow into the pipe. 6.2. Fill After the wetland has been graded to a depth of 2' with side slopes of 2:1 and lined with 30 mm %W PVC liner(see Section 5), it shall be backfilled with soil and then gravel. 6.2.1. Base Laver Approximately 6" of native earth backfill shall be placed uniformly on top of the liner. The earthen layer will function as a base to protect the PVC liner and as a foundation material for the %W plant roots. 6.2.2. Gravel Fill Eighteen inches of gravel fill shall be placed onto the earth layer. The gravel shall be a clean locally available material such as that used for concrete. The diameter of the gravel is the discretion of the Winery, although in general gravel between '/2 inch and 1 inch in size has been found to provide the best combination of hydraulic conductivity and void ratio. The gravel shall be a uniform grade so that it has a porosity of at least 33%, and, if possible, at least 98% of the �► material shall pass the #100 sieve. Gravel shall have a minimum Mohs hardness of 6 to minimize the production of fines during transit and placement. The gravel shall be placed level and shall be free of vehicular tracks and depressions or ridges. %a' 6.2.3. Inlet and Outlet Fill For a minimum of three feet surrounding the inlet and outlet laterals a larger material than the gravel specified in Section 6.2.2 shall be used. In these areas rock shall be 11/2 to 3 inches in %W diameter. The larger rock will help to settle out particles and promotes the uniform distribution of effluent. 7. VEGETATION Vegetation, both live and dead, contributes to both the performance and aesthetics of subsurface �kw flow wetlands. Establishing a viable wetland plant population is often the least familiar aspect of '`• wetland construction, therefore it is important to become acquainted with installation techniques `, before planting. After the initial planting it will be necessary to monitor the water level in the %W wetland and it may be necessary to replant some areas at a later time. The rest of this section discusses the recommended plant species for Jessie's Grove Winery and some planting specifications. 7.1. Species Selection The majority of the wetland (-80%) should be planted in native bulrush and the remainder can be cattails (-20%). The Winery may introduce other local native wetland species as they wish for aesthetic purposes. Recommended Bulrushes: California Tule, (Scirpus californicus) 6-12 feet tall ~ 1ESSIE'S GROVE WINERY 30 MAY 2002