SR0082155 SSNL - Laserfiche WebLink

Home Browse Search

Soil Suitability/Nitrate Loading Study Irerracon Proposed Commercial Truck Yard ■ Stockton, CA August 16, 2019■ Terracon Project No. NA197053 2.4 Discussion of Nitrate Loading Results 2.4.1 Total Nitrate Impact Based on the method and assumptions described, the result of the nitrate loading balance (9.5 mg/L N) indicates that the development on the parcel is not anticipated to cause a buildup of nitrates in the aquifer the MCL of 10 mg/L-N. 2.4.2 Methods of Mitigation Based on the favorable nitrate loading results, mitigation measures appear unwarranted. 3.0 CONCLUSIONS AND RECOMMENDATIONS The soils encountered on the site generally consisted of silty sand. A satisfactory percolation rate of 9.62 minutes per inch at 3.5 feet was obtained in the proposed leachfield. Hardpan is anticipated in the upper five feet soil. The site's former septic systems and adjoining properties septic systems utilize standard leach lines and/or seepage pits or filter beds. Depth to groundwater is anticipated at 17 feet bgs. There is no groundwater well on the site; therefore, a water sample was not collected. The result of the nitrate loading balance (9.5 mg/L- N) indicates that the proposed development is not anticipated to cause a buildup of nitrates in the aquifer above the MCL; therefore, mitigation measures appear unwarranted. In summary, the parcel appears suitable for the proposed development. The septic system design should accommodate the peak flows and follow the San Joaquin County OWTS standards where applicable. 4.0 LIMITATIONS As indicated, our study takes into account the subject property only with the sewage load applied over the property site area. The study does not take into account surrounding properties and/or lands. The method utilized for the nitrate loading analysis is based on a simple mass balance formula, discussed in a published article by Hantzsche and Finnemore (1992), which provides a convenient and simplified method to estimate long-term groundwater nitrate impacts on an area- wide basis. A more detailed analysis was not requested nor intended. Our professional services were performed, our findings obtained, and our conclusions proposed in accordance with generally accepted engineering principles and practices. This warranty is in lieu of all other warranties either expressed or implied. Test findings and statements of professional opinion do not constitute a guarantee or warranty, expressed or implied. Responsive■ Resourceful ■ Reliable 17