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Woodbridge Community Church <br /> Page No. 2 <br /> mounted drill rig utilizing 4. 5 inch diameter continuous flight <br /> auger. For approximate location of the test hole see the <br /> attached Parcel Map. The test hole was logged by an engineer and <br /> a description of the soils encountered is presented on the <br /> attached Log of Test Hole. The first 7 feet consisted of a silty <br /> fine to medium sand. This was underlain by a 1 foot stratum of <br /> slightly cemented clayey fine sandy silt. The cemented soil was <br /> underlain by various strata of silty sands and silts. For a more <br /> detailed description of the soils encountered see the log of test <br /> hole. <br /> A shallow percolation test was performed next to the profile <br /> hole. A 6-inch diameter by 36-inch deep test hole was excavated. <br /> Two inches of gravel was placed in the bottom of the hole. A 2- <br /> inch diameter perforated pipe was then placed in the hole and <br /> backfilled with gravel. The last half hour of the test readings <br /> was witnessed by a county health official and the test data " <br /> obtained is attached. The percolation rates have been adjusted <br /> to account for the gravel and pipe backfill. Calculations for <br /> adjustments are on the test data sheets. <br /> A summary of the test results is presented next: <br /> Diameter of Depth of <br /> Test No. Hole (in. ) Hole (ft. ) Percolation Rate (min/in) <br /> PT-1 6 .0 3.0 4. 1 <br /> NITRATE LOADING STUDY <br /> The nitrate loading study was performed by using a mass <br /> balance equation to obtain a simplified prediction of groundwater <br /> nitrate buildup from the proposed installation of a septic <br /> system. Assumptions that were made and calculations are <br /> attached. Due to approximately one-half of the future developed <br /> lot being covered with pavement and the other with landscaped <br /> vegetation, it was assumed that ground water recharge was equal <br /> to one-quarter of the yearly irrigation. It was also assumed <br /> that the yearly deep percolation of rainfall is 50 percent of the <br /> average yearly rainfall due to the above conditions and the <br /> presence of some subsurface cemented soils. A ground water <br /> sample from a well located in the adjacent mobile home park was <br /> obtained and tested for nitrate in order to determine a <br /> background level . Test results indicated a non-detected nitrate <br /> level (see attached laboratory results) . Conservatively the <br /> minimum detection limit of 0 . 4 mg/l was used for our analysis. <br /> pER30y <br /> � N <br /> -(, W <br /> SSS pG\ <br />