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Soil Suitability/ Nitrate Loading Study 1 rierracon Lease Property m Acampo, California December 17, 2021 Terracon Project No. NA217090 1.6.2 Number of Percolation Tests Three percolation tests (131, B2, and 133) were performed. 1.6.3 Boring Preparation and Presaturation The percolation test borings (131, B2, and 133) were excavated on December 3, 2021. Approximately two inches of " pea gravel" was placed in the bottom of the open borings. A 2.0 - inch diameter PVC pipe with perforations towards the bottom was installed on top of the gravel and the annular space was backfilled with " pea gravel". Presaturation of the percolation test holes occurred on December 6, 2021 approximately 24 hours prior to the day of testing. The depth of water used to pre-soak the shallow borings was approximately 1.0 foot above the top of the gravel. It should be noted, boring B2 was drilled to 21 feet bgs until auger refusal and collapsed to 18 feet bgs during boring preparation. Boring 63 was handaugered to 2.25 feet bgs until auger refusal. 1.6.4 Condition of Borings after Presaturation Borings 61 and B2 were dry and intact after the 24-hour pre-soak period. Boring 63 had water in the boring after the pre-soak period. 1.6.5 Percolation Test Procedure Percolation tests were conducted for the three borings on December 7, 2021 in accordance with the requirements of the San Joaquin County EHD. Borings B1 and B2 each had a percolation test duration of four hours. Boring B3 had a percolation test of 30 minutes. The last half an hour of the test was observed by Mr. Aaron Gooderham of the EHD. Measurement of the water level during the percolation tests was from a fixed reference point on the PVC casing using a calibrated Solinst electric water level detector with a depth accuracy of 0.01 feet. All tabulated values on the field data sheet (Appendix E) are in decimal feet. After water drop was observed, the borings were checked for refill. The borings were refilled as necessary to maintain approximately 0.5 feet (6 inches) of water above the bottom level of the percolation test holes. The readings were taken every 30 minutes for a period of four (4) hours for borings B1 and B2. 1.6.6 Percolation Test Forms and Results A shallow percolation test is defined by the EHD as being between 36 and 42 inches in depth. While a deep percolation test is defined by the EHD as being between 42 inches and 25 feet in depth. The shallow percolation test must demonstrate a satisfactory percolation rate of less than or equal to 60 minutes per inch drop in water level within the existing septic system disposal field of a parcel to utilize a standard septic system and 30 minutes per inch or less for septic pits. Details of the percolation tests are summarized in the table below. Responsive ■ Resourceful ■ Reliable 11