Laserfiche WebLink
Soil Suitability and Nitrate Loading Evaluation-Update-2 Page 13 of 18 <br /> Great Pacific Nut—Nut Processing Facility Expansion <br /> 3501 Lehman Road, Tracy, California <br /> September 6, 2019 CTE Job#25-071 OG <br /> hots = 11+ 12= 180 gal/day+300 gal/day=480 gal/day <br /> Itota = Volume rate converted to inches/year and averaged over the gross <br /> developed area(using 10 acres): <br /> 480 gal/day x 365 days/year x ft3/7.48 gal x 1 acre/43,560 ft2 x 12 in/ft <br /> x 1/10 acre=0.645 inches/year. <br /> NW = Nitrate concentration of nitrified leach-field effluent is assumed to be on <br /> the order of 40 mg/l (average is 35 to 45 mg/l per Hantzsche and <br /> Finnemore; 1992). <br /> D = Fraction of nitrate-nitrogen loss due to dentrification of leach field effluent <br /> is assumed to be 0.25 (most representative of typical onsite sewage <br /> disposal situations per Hantzshe and Finnemore, 1992 & U.S. EPA, 1980, <br /> 1981). <br /> R = Average recharge rate due to rainfall (taken as 80%of annual 10.5 in/yr <br /> with 20%assumed lost to offsite drainage &evapotranspiration)= 8.4 <br /> in/year(average taken from USDA SCS Soil Survey of San Joaquin <br /> County,Fig 3, page 8, dated October 1992). <br /> Nb = Background nitrate nitrogen concentration of rainfall recharge at the <br /> water table typically falls between 0.5 and 1.0 mg/l (per Hantzsche and <br /> Finnemore; 1992) and is assumed to be 1.0 mg/l. <br /> Our nitrate calculation is as follows: <br /> NC _ [I (NW) (1-D)+R(Nb)]/(I+R) <br /> NC _ [0.645(40) (1.0-0.25) + 8.4 (1.0)] /(0.645+8.4)=3.07 mg/l as N <br /> The calculated nitrate (3.07 mg/L as N) for groundwater Nitrate-Nitrogen Impacts is <br /> below the State drinking water standard of 10 mg/L for nitrogen (N). <br /> 8.00ONCLUSIONS <br /> A suitable soil condition for septic percolation tests in San Joaquin County is defined as a <br /> stratum capable of percolating water between 1 and 60 minutes per inch (min/inch) at a <br /> depth of up to 3.5 feet below existing site grade. CTE's percolation test results at the <br /> proposed leach field were 16.0 min/inch at a depth of 38 inches. Based on these results, <br /> SACRAMENTO • FREMONT • MODESTO <br /> INSPECTION&TESTING•GEOTECHNICAL•ENVIRONMENTAL-CONSTRUCTION ENGINEERING <br />