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Soil Suitability /Nitrate Loading Study Irerracon <br />Ehlers Property Lodi, California <br />May 13, 2021 Terracon Project No. NA217019 <br />Table 4. <br />Expected Onsite Maximum Septic Tank Usage <br />Gallons per day (GPD). Gallons per 10 hour day (GPD10). Gallons per 12 hour day (GPD12) <br />Employee Effluent 10 hour day is 15 gpd x 1.25 = 18.75 gpd (GPD10) <br />Employee Effluent 12 hour day is 15 gpd x 1.5 = 22.5 gpd (GPD12) <br />Visitor effluent 5 gpd. Visitors are assumed to be onsite less than 8 hours per day. <br />The maximum daily flow rate for the grain operations is approximately 93.75 gpd. The proposed <br />hemp operation is anticipated to add approximately 127.50 gallons of effluent per day for a <br />combined maximum daily flow rate of approximately 221 gpd for the facility. <br />1.4 Groundwater Information <br />1.4.1 Groundwater Depth and Gradient <br />During our field activities, groundwater was encountered at approximately 5.5 feet bgs within our <br />soil profile boring B2 which was advanced to 6.0 feet bgs. There were no Well Completion <br />Reports for the onsite well. <br />Terracon searched the California Department of Water Resources Sustainable Groundwater <br />Management Act (SMGA) Data Viewer, however, groundwater data was not available for the site. <br />Based on a review of nearby Well Completion Reports, groundwater levels near the site ranged <br />between 3.8 and 6 feet bgs. The groundwater flow direction and the depth to shallow, unconfined <br />groundwater, if present, would likely vary depending upon seasonal variations in rainfall and other <br />hydrogeological features. Without the benefit of on-site groundwater monitoring wells surveyed to <br />a datum, groundwater depth and flow direction beneath the site cannot be directly ascertained. <br />1.4.2 Potential Groundwater Contamination Issues <br />Potential groundwater contamination can occur from a number of sources including historical <br />petroleum hydrocarbon use, agricultural activities, dairies, septic systems, and storm water <br />infiltration. As per EHD requirements nitrate as N and 1,2-dibromo-3-chloropropane (DBCP) have <br />been included as part of the SSS discussion. Identifying potential groundwater contamination <br />other than nitrates and DBCP is beyond the scope of work for this report. <br />The presence of nitrates is not uncommon in shallow groundwater aquifers in San Joaquin County <br />and other parts of the Central Valley. Nitrate in groundwater occurs as a result of the application <br />Responsive ■ Resourceful ■ Reliable 7 <br />Maximum <br />Septic <br />Number <br />Hours of <br />Number of <br />Employee Effluent <br />Number <br />Visitor <br />Septic Tank <br />Usage <br />System <br />Facility Use <br />Operation <br />Employees <br />(18.75 GPD10) <br />Visitors <br />Effluent <br />Employee <br />No. <br />per day <br />per day <br />(22.5 GPD12) <br />per day <br />(x5 GPD) <br />GPD + Visitor <br />GPD <br />Grain Facility <br />10 <br />5 <br />93.75 <br />0 <br />0 <br />93.75 <br />1 <br />Proposed <br />12 <br />5 <br />112.50 <br />3 <br />15 <br />127.50 <br />Hemp Facility <br />Total <br />221.25 <br />Gallons per day (GPD). Gallons per 10 hour day (GPD10). Gallons per 12 hour day (GPD12) <br />Employee Effluent 10 hour day is 15 gpd x 1.25 = 18.75 gpd (GPD10) <br />Employee Effluent 12 hour day is 15 gpd x 1.5 = 22.5 gpd (GPD12) <br />Visitor effluent 5 gpd. Visitors are assumed to be onsite less than 8 hours per day. <br />The maximum daily flow rate for the grain operations is approximately 93.75 gpd. The proposed <br />hemp operation is anticipated to add approximately 127.50 gallons of effluent per day for a <br />combined maximum daily flow rate of approximately 221 gpd for the facility. <br />1.4 Groundwater Information <br />1.4.1 Groundwater Depth and Gradient <br />During our field activities, groundwater was encountered at approximately 5.5 feet bgs within our <br />soil profile boring B2 which was advanced to 6.0 feet bgs. There were no Well Completion <br />Reports for the onsite well. <br />Terracon searched the California Department of Water Resources Sustainable Groundwater <br />Management Act (SMGA) Data Viewer, however, groundwater data was not available for the site. <br />Based on a review of nearby Well Completion Reports, groundwater levels near the site ranged <br />between 3.8 and 6 feet bgs. The groundwater flow direction and the depth to shallow, unconfined <br />groundwater, if present, would likely vary depending upon seasonal variations in rainfall and other <br />hydrogeological features. Without the benefit of on-site groundwater monitoring wells surveyed to <br />a datum, groundwater depth and flow direction beneath the site cannot be directly ascertained. <br />1.4.2 Potential Groundwater Contamination Issues <br />Potential groundwater contamination can occur from a number of sources including historical <br />petroleum hydrocarbon use, agricultural activities, dairies, septic systems, and storm water <br />infiltration. As per EHD requirements nitrate as N and 1,2-dibromo-3-chloropropane (DBCP) have <br />been included as part of the SSS discussion. Identifying potential groundwater contamination <br />other than nitrates and DBCP is beyond the scope of work for this report. <br />The presence of nitrates is not uncommon in shallow groundwater aquifers in San Joaquin County <br />and other parts of the Central Valley. Nitrate in groundwater occurs as a result of the application <br />Responsive ■ Resourceful ■ Reliable 7 <br />