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April 17, 2019 BGG Job No. G001.05 _aQ'M'VIk Soil Borings and Test Pits On January 24,2019,we performed a percolation test in the area of the proposed guard station,as shown on Plate 2,Site Plan.The locations of our previous percolation tests at the site are also shown on the Site Plan. Percolation testing was performed in open test pits by manually digging or excavating with a backhoe to reach the desired,test depth. Materials encountered in the test pits were visually classified in —the field arid-togs were"recorded. The test pit logs are contained in Appendix B. \)-&V � , On September 25,2018, BGG conducted,a la exploration in the site vicinity,which consisted of drilling and logging two borings to depths of 20-feet and 29'/2-feet bgs,in the approximate locations shown on Plate 2—Site Plan. The borings were advanced using a truck-mounted drill rig equipped with solid flight augers and the soil was sampled with SPT (2-inch outer diameter [OD]) and Modified California(2.5-inch OD)split spoon samplers. Materials encountered in the borings were visually classified in the field and logs were recorded. The boring logs showing soil classification and blow counts are also contained in Appendix B. Based upon our previous field explorations,the general soil profile at the site can be characterized as a sequence of predominantly sandy and silty soils. The upper 3 to 4 feet of soil consists of light to medium brown, loose,dry,silty sand. This upper 3 to 4 feet is loose as a result of disturbance from vineyard removal. Below 3 to 4 feet is a weakly to moderately cemented hardpan layer consisting of brown and gray,dense,moist,silty sand and sandy silt. Below the hardpan,the silty sand is medium dense to a depth of 10 to 15 feet, whereupon the sandy soils become dense. More detailed information of materials encountered in the exploratory test pits and borings are included in the logs in Appendix B. Discussion of Soil Lithology Based on the soil observed in the test pits and borings and our previous percolation testing at the site,there appears to be potential for percolation. Sandy soils generally have a greater potential for percolation than fine-grained(silts and clays)or cemented soils. Percolation testing is discussed in the following section. Percolation Testing Procedure Field percolation testing has been performed at the site on several occasions.On January 24,2019,we performed a percolation test in the area of the proposed guard station septic system, as shown on Plate 2—Site Plan.The locations of our previous percolation tests at the site are also shown on the Site Plan. Percolation testing was performed in open test pits by manually digging or excavating with a C$ backhoe to reach the desired test depth. The soils encountered were classified and logged, and the L' bottom of the test its were then saturated b filling with water forapproximate l 2 hours. After P Y g --.Y- - saturating,double ring infiltrometers,having 6-inch diameter inner rings and 12-inch diameter outer rings,were utilized for percolation testing by setting the rings into the saturated soil surface at the bottom of the test pits, filling with water, and recording the rate of fall. Percolation Test Results The following are the results of the field percolation testing for the proposed guard station: BAEZ GEOTECHNICAL GROUP Soil Suitability Study and Nitrate Loading Study-DFV Guard Station Page 4