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5.0 Environmental Analysis 5.4 Landform Alteration/Visual Quality <br />Avion Project SEIR <br />Page 5.4-4 <br />5.4.4.2 Impacts <br />Each of the individual thresholds is addressed below. <br />a. Would the project alter more than 2,000 cubic yards of earth per graded acre by either excavation or <br />fill? <br />Project construction would grade 15.69 acres of the 41.48-acre project site (37.8 percent). Overall, <br />the project proposes approximately 296,000 cubic yards of cut (maximum depth of 52 feet) and <br />296,000 cubic yards of fill (maximum depth of 64 feet) over the approximately 15.69-acre graded <br />area, resulting in a net balance of grading on the project site. The project would therefore result in <br />approximately 18,866 cubic yards of earthwork per graded acre. This amount of earthwork would <br />exceed the 2,000 cubic yards of earth graded per acre threshold. Since grading would alter more <br />than 2,000 cubic yards of earth per graded acre by either excavation or fill, the following is an <br />analysis of the additional criteria pursuant to the City’s thresholds. <br />1) Would project grading disturb steep (25 percent gradient or steeper) slopes in excess of the <br />encroachment allowance of the ESL regulations and steep hillside guidelines (LDC, Section 143.0110)? <br />As described in Land Use Section 5.1.3.1, the project is subject to the ESL regulations of the San <br />Diego Land Development Code, because the project site includes naturally steep hillsides. Project <br />grading would encroach into 7.86 acres of steep slopes, which constitutes 18.95 percent of the <br />project site. Although the project would impact an additional 5.50 acres of steep slopes to establish <br />manufactured slopes that would be revegetated for erosion control purposes, Section 143.0142(g) of <br />the Steep Hillsides Guidelines states that erosion control measures outside of the Coastal Overlay <br />Zone are not subject to the 25 percent development area regulations for steep slopes. Therefore, <br />the project’s encroachment of 7.86 acres is within the 25 percent encroachment allowance as <br />permitted by the City’s ESL ordinance. <br />2) Would the project create manufactured slopes higher than 10 feet or steeper than 2:1 (50 percent) <br />slope gradient? <br />The project would create manufactured slopes over 10 feet in height by creating cut slopes of up to <br />52 feet in height on the perimeter of the development area. These manufactured cut slopes would <br />have a gradient of 2:1 (50 percent). All manufactured slopes on the project perimeter would be <br />revegetated with native plant material in order to blend with the adjacent natural hillside, consistent <br />with the City’s grading and brush management regulations. Landscaping would help reduce the <br />appearance of manufactured slopes relative to the natural landform. <br />3) Would the project result in a change in elevation of steep natural slopes from existing grade to <br />proposed grade of more than 5 feet by either excavation or fill, unless the area over which excavation <br />or fill would exceed 5 feet is only at isolated points on the site? <br />Overall, the project proposes approximately 296,000 cubic yards of cut (maximum depth of 52 feet) <br />and 296,000 cubic yards of fill (maximum depth of 64 feet) over the approximately 15.69-acre <br />graded area, resulting in a net balance of grading on the project site. The maximum depths of cut <br />and fill for proposed grade would exceed 5 feet.