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ADDITIONAL INFORMATIONREQUIREMENTS • 2 <br /> CITY OF LATHROP WASTEWATER PLANT NO. 2 <br /> LATHROP,SAN JOA QUINCOUNTY <br /> 6. In the 23 May 2001 RWD no information on the depth to groundwater was provided. Based on <br /> information available in other parts of Lathrop, and the close proximity of the San Joaquin River, <br /> the groundwater table is likely shallow. The RWD does not present how storage of wastewater in <br /> an unlined pond is protective of groundwater quality. It is unclear how percolation of treated <br /> wastewater from the storage pond with residual nitrogen(7 mg/1) and ammonia(1 mg/1)will not <br /> impact groundwater quality. Therefore the proposal to store wastewater in an unlined pond is not <br /> acceptable. Please resubmit the water balance with the following additional information: <br /> a. Assume the pond is lined and no leakage occurs. Storage pond requirements shall include the <br /> 100-year annual total rainfall distributed in accordance with historical patterns; <br /> b. No application of wastewater to land application areas is allowed during rain events or when <br /> the soil is saturated; and <br /> c. Identify all assumptions used in the water balance including percolation rate, land application <br /> area size, and safety factor used for long term percolation rate. <br /> 7. Provide a complete description of all interim treatment systems. The description must be sufficient <br /> to allow evaluation of the proposed system. At a minimum the description shall include: <br /> a. Average dry weather flow and peak wet weather flow rates (flow rates shall be based on the <br /> treatment capacity and available land application area capacity whichever is less); <br /> b. Provide information on the collection systems planned for each phase of development and <br /> maintenance activities that will be performed. Describe emergency electrical generators and <br /> emergency notification equipment(autodialers)planned for the wastewater treatment system <br /> and collection system. <br /> c. Provide a description of planned treatment processes and estimate effluent quality(BOD,total <br /> suspended solids, settleable matter, electrical conductivity,total coliform organisms, and pH); <br /> d. Storage facilities for treated wastewater and emergency storage facilities (materials,thickness, <br /> and construction methods proposed for pond liner systems) Description of effluent storage <br /> system shall include, at a minimum: <br /> i. Surface area, total depth, and net volume capacity(at 2-foot freeboard level) for each <br /> storage pond; <br /> ii. Address the California Department of Water Resources Division of Safety of Dams <br /> requirements for impoundment dam safety; <br /> iii. Provide cross sections of the storage pond including elevations of berms, groundwater <br /> table,pond bottoms, and surrounding grades; <br /> iv. The proposed storage pond is approximately 400 feet by 300 feet, describe means to <br /> prevent wind driven wastewater waves from overtopping the storage pond berms; and <br /> v. Operation and maintenance procedures. <br /> e. Provide site specific data on infiltration rates in all land application areas. Double ring <br /> infiltrometer tests (ASTM D 3385-94) are an acceptable method of determining the infiltration <br /> rate for typical land application areas. Please refer to the method's hydraulic capacity limits <br /> and determine if it is appropriate or provide information on an alternative method prior to <br /> testing; <br /> C:Nmisi FiieslSiVaLLeJimP_WWTF`y�MT��liflNlu3nI OOC <br />