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D. GROUNDWATER INFORMATION NLS§ 2.1, SSS§ 4.1. Groundwater depths and elevations throughout San Joaquin County are illustrated on maps published by the County Flood Control and Water Conservation District. The Lines of Equal Depth Maps indicates the depth to groundwater in the Spring of 1999 was 60 ft. The Well Log for the new onsite domestic well indicates the standing water level depth was 82 ft in February 2018; thus, a 20 ft drop in 22 years. The Lines of Equal Elevation Maps indicate groundwater directional flow is in a northwesterly direction. NLS§ 2.2, 3.1, SSS§ 2.1, 4.2. Properties to the north, south, east and west are currently in agricultural production, dairy, and rural residential. Considering this area has been farmed for decades, there is a significant potential for nitrate contamination to the underlying groundwater from nitrogen fertilizer applications and residual organic matter decomposition. However, the well water test results below indicate that this may not be the case at this point in time. NLS§ 2.3, SSS§ 4.3, 4.4, 4.5, 4.6. There one domestic well on the property. The almond orchard is irrigated by Oakdale Irrigation District water (OID). Test results in Appendix F illustrate the nitrate as nitrogen concentration to be 4.73 mg/L, or approximately one-half of the Maximum Contaminant Level (MCL). TABLE 3 BARBER DOMESTIC WELL: ANALYTICAL RESULTS OF TESTED CONSTITUENTS SAMPLE ID NITRATE AS NITROGEN DBCP/EDB TOTAL ALKALINITY Barber 4.73 mg/L ND 148 mg/L MCL = 10 m Non -Detect Calculation of Alkalinity Requirement for Nitrification The nitrate -nitrogen loading calculation results are contingent upon the environmental factors required for nitrification to occur. These conditions include soil pore -space oxygen content, soil temperature, pH, electrical conductivity, organic matter, cation exchange capacity, and alkalinity. Alkalinity in wastewater effluent is derived from the on-site well water, in addition to the introduction of wastes in the effluent. Nitrification consumes approximately 7.1 mg of alkalinity for every mg of ammonia -nitrogen (NH4 N) oxidized. Nitrification of the average Total Nitrogen (TN) concentration of 62 mg/L, as determined below, would require: 62 mg/L NH4-N x 7.1 mg CaCO3 = 440 mg/L alkalinity. The well water provides 148 mg/L. Therefore, soil alkalinity and alkalinity from wastes must provide additional alkalinity concentration for nitrification to occur. E. SURFACE WATER INFORMATION The rainfall recharge factor used in the Hantzsche-Finnemore equation below will be based upon water balance documentation from Norman Hantzsche found in Appendix F. This Water Balance Analysis of the Stockton area is applicable for this project according to Mr. Hantzsche. Page -4- Chesney Consulting