SU0011793_SSNL - Laserfiche WebLink

Home Browse Search

Soil Suitability/Nitrate Loading Study Irerracon Proposed Global Carrier Inc. . Manteca, California August 8, 2018■ Terracon Project No. NA187034 1.3.7 Expected On-Site Maximum Septic Tank Usage According to Mr. Vieira, the existing residence is proposed to be converted to an office with break room for up to three people eight hours per day, five days per week. The existing septic system will service this new office. Mr. Vieira indicated that the proposed 8,000 SF trucking facility will require two bathrooms including two sinks and two toilets and a new septic system will be developed to service this new facility. Mr. Vieira indicated up to four employees will utilize the trucking facility eight hours per day, five days per week with up to ten visitors/truckers per day, year round. Mr. Vieira indicated one restroom in the new truck facility will remain open for visitor use 24 hours per day year seven days per week. Mr. Vieira indicated there are no showers planned for the facility. Based on a the San Joaquin County Onsite Wastewater Treatment Systems Standards (EHD 42- 014) dated January 2017, the office proposed usage rate will be calculated at 30 gallons per person per day similar to day workers at schools/offices. The truck facility proposed usage rate will be calculated at 15 gallons per person per day for similar to industrial buildings with no food cafeteria. Visitor/trucker usage will be calculated at 5 gallons per person per day similar to airport passengers. Based on conversations with Mr. Vieira, the property will have a maximum daily usage of 200 gallons per day (30 gallons per 3 office employees, 15 gallons per 4 tire/brake shop employees, and 5 gallons per 10 visitors/truckers). 1.4 Groundwater Information 1.4.1 Groundwater Depth and Gradient On June 25, 2018, groundwater was not encountered in our percolation test boring (B1) excavated to a depth of 3.5 feet below grade surface (bgs) or soil profile boring (132) excavated to a depth of 10 feet bgs. According to the San Joaquin Flood Control and Water Conservation District Groundwater Reports, groundwater depth and elevation maps dated Fall 2015 to Spring 2016, depth to groundwater lies between approximately 30 and 50 feet bgs with an anticipated northerly flow direction. The groundwater flow direction and the depth to shallow, unconfined groundwater, if present,would likely vary depending upon seasonal variations in rainfall and other hydrogeological features.Without the benefit of on-site groundwater monitoring wells surveyed to a datum, groundwater depth and flow direction beneath the site cannot be directly ascertained. 1.4.2 Potential Groundwater Contamination Issues The presence of nitrates is not uncommon in shallow groundwater aquifers in San Joaquin County and other parts of the Central Valley. Nitrate in groundwater occurs as a result of the application of fertilizers, livestock waste, and untreated septic tank waste. Nitrate is mobile and often accumulates in the shallow groundwater zones. Responsive■ Resourceful ■ Reliable 7