SU0011127 SSNL - Laserfiche WebLink

Home Browse Search

Soil Suitability Nitrate Loading Study 1 ferracon Recreation Vehicle Service Facility■ Lockeford, CA April 12, 2017■ Terracon Project No. NA177006 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 indicates that the development on the parcel should not cause a buildup of nitrates in the aquifer above 10 mg/L-N. t 2.4.2 Methods of Mitigation Because of the favorable result of the nitrate loading calculation, no mitigation measures are warranted. 3.0 CONCLUSIONS AND RECOMMENDATIONS In summary, percolation rates meet the minimum EHD standards at a depths of 25 feet bgs in the proposed septic leach field area. The parcel appears suitable for the use of a standard septic system utilizing shallow leach lines and septic pits designed for the intended usage. The foregoing investigation and percolation test results indicate the site consists of surface silty sand where leach lines may be utilized, however as indicated, the shallow percolation test failed. The area is known for subsurface clay statum and hardpan that undedy the near surface sands which doesn't allow satisfactory percolation via leach lines. For this reason, we are recommending seepage pits be used with leach lines, similar for Sandy Clay loam soil. All final septic system construction should follow the San Joaquin County On-Site Wastewater Disposal Standards where applicable. The seepage pits should extend to a depth of 25 feet, maximum allowed by the County, in order intercept the sandy stratum encountered between 20 and 25 feet. Based on the method and assumptions described, the results of the nitrate loading balance indicated that the proposed development at the site should not cause a buildup of nitrates in the aquifer above 10 mg/L-N. Groundwater sampled from a drinking water well near the site was analyzed for nitrate, EDB, and DBCP, and all were reported to be below the limit for human health hazard. 4.0 LIMITATIONS 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 (3-,2, 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 16