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II. SOIL SUITABILITY STUDY FINDINGS ►W ; 1 W : � :. i _ ; : o]i a ] i ce"Lil i ��"i"1 af1 41, rM 1 00 SSS§ 1.1. The Parcel is directly west of the City of Tracy Wastewater Treatment Facility and Sugar Cut (a.k.a. Dredger Cut) off of Old River. These two bodies of water contribute significant influence to the water table underlying the project. Land use to the immediate west is an agricultural recycling company, which has also contributed significant nitrogen influence to the soil under the subject property and to the underlying groundwater. To the north is agricultural production land. SSS§ 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 6.8. Applications permits found in EHD files were available for review to determine the number of permits issued for repairs/replacements/additions to existing systems within the one-half mile radius study area. The septic systems in this locale are sparse so data is limited. There were no applications found on Sugar Road and six on Holly Drive. Given the clay content of the on-site and surrounding soils, septic system longevity can be considered limited and septic system failures will eventually occur. However, all the permits for repairs/replacements, except one, is decades old. This may indicate that originally installed systems were insufficient in size to manage effluent flow volumes. The project site will have level terrain after earthwork grading is completed; consequently, there is no need to incorporate design considerations for slopes within the effluent disposal area. B. SOIL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS SSS§ 5.2. The UC Davis Soil Web indicates the property as W -Water. However, the surrounding, and therefore the soils underlying the parcel are the following: 85% - Pescadero clay loam (4211), 4% - Egbert clay loam, 4% - Merritt clay loam, 4% - Capay clay, and 3% - Willows clay. The surface and subsurface soil investigation began on February 24, 2019 with the drilling of one 24" and one 36" deep perc test borings. NLS§ 1.1, 1.2. Surface soil samples and auger cuttings samples from the bottom of the 24" test boring were obtained for chemical analysis. As noted on the-A&L Laboratory Soil Report in Appendix B, analyses of the soil sample quantifies a number of constituents that influence nitrate loading for this project. The important parameters for nitrate loading assessment are the organic matter, Estimated Nitrogen Release (ENR), pH, cation exchange capacity (CEC), and the nitrate - nitrogen content of the soil. The soil nitrate -nitrogen concentration was determined to be an extremely high 189 ppm at the 24" depth. This translates to approximately 400 lbs of nitrate -nitrogen per acre. Therefore, more than 450 units (lbs/ac) of nitrogen already exist in the subject property soils, which greatly exceeds (by 2-3x) typical agronomic rates. Page -2- Chesney Consulting