SR0082465_SSNL - Laserfiche WebLink

Home Browse Search

II. SOIL SUITABILITY STUDY FINDINGS A. SUBJECT PROPERTY AND SURROUNDING STUDY AREA INFORMATION SSS§ 1.1. The subject property was under agricultural production for decades and is currently undergoing development as the Delta Charter Schools, with all portable classrooms currently onsite. Development also consists of the installation of underground stormwater conduits and chambers, parking and driveway areas, and a baseball diamond and football field. In 2015, it was proposed to subdivide the property into seven, 2 acre parcels. These subdivision documents are found in Appendix I. It is unknown why this subdivision project was terminated. Land use to the immediate north, south and east is rural residential, all on onsite wastewater treatment systems, to the west is industrial/commercial, and surrounding the property is agricultural production land,primarily almond orchards. SSS§3.1,3.2,3.3,3.4,3.5,3.6,3.7, 6.8. Permit applications within the one-half mile radius study area from the property were reviewed for repairs/replacements/additions to existing septic systems. Five permits primarily for repairs were found. This can be considered a medium number of permits within this study area, which suggests a medium lifespan for the proposed OWTS. The project site has level terrain; consequently, there is no need to incorporate design considerations for slopes within the effluent disposal area. The disposal area will be installed under the grass field area which will be potentially beneficial for the evapotranspiration of effluent. B. SOIL PHYSICAL CHARACTERISTICS AND ANALYTICAL TEST RESULTS The UC Davis Soil Web indicates the effluent disposal area soils to consist of Capay clay(#121), with El Soyo, Stomar and Vernalis clays. SSS§5.2. The surface and subsurface soil investigation began on June 30, 2020. Four, 40" deep percolation test borings were hand-drilled near the four corners of proposed disposal area, within the existing grass ball fields. The four boring locations are designated as Northeast Corner 40" (NEC40), Northwest Corner 40" (NWC40), Southeast Corner 40" (SEC40) and Southwest Corner 40" (SWC40). NLS§ 1.1, 1.2. Soil samples for chemical and texture (particle size) analyses were retrieved from the 36"40" depths. In addition, a backhoe test pit was dug directly adjacent to this proposed leachfield area and soil samples retrieved from the 6 ft and 10 ft depths. As noted on the Laboratory Soil Analysis Report in Appendix D, chemical analyses of the retrieved soil samples quantify several constituents that influence nitrate loading for this project. The important parameters for nitrate loading assessment are the organic matter, clay content, pH, cation exchange capacity(CEC), and the nitrate-nitrogen content of the soil. Page -2- Chesney Consulting