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Mitigation Measure 4.4-3h: Where steeper slopes greater than 3:1 are desired, supplemental slope stabilization measures such as geogrid enforcement and/or the use of select fill shall be employed. Drainage benches shall also be provided at a 30-foot minimum intervals, and construction shall follow the structural setbacks of the CBC. Accordingly, structures shall be: (I) set back from the top of the slope by a minimum of one-third of the slope height or a maximum of 40 feet; and (2)set back from the bottom of the slope by a minimum of one-half of the slope height or a maximum of 15 feet. Alternative setbacks may be addressed on a per lot and foundation design basis. Significant Impact Impact 4.4-4: Expansive soils and bedrock materials are present within project boundaries and construction on expansive soil could cause foundation and other structural failures, particularly at lots traversed by a cut/fill transition. Finding Changes or alterations have been required in,or incorporated into,the project which mitigate or avoid the significant effects on the environment. Facts in Support of Finding The City of Pleasanton has adopted the following measures which will reduce potential impacts related to expansive soils and bedrock materials to a less-than-significant level: Mitigation Measure 4.4-4: Cut lots shall be overexcavated 2 feet, scarified 12 inches, and recompacted so as to provide a zone of at least 3 feet of reworked and compacted soil. Additionally, cut/fill transition lots should be overexcavated so as to provide a minimum of 3 feet of a uniform thickness of engineered fill within the entire foundation area. In addition,exposed soils shall be kept moist by watering for several days before placement of concrete. Significant Impact Impact 4.4-5: Compressible soils and non-engineered fills are present within project boundaries and construction on these soils could cause foundation and other structural failures. Finding Changes or alterations have been required in, or incorporated into,the project which mitigate or avoid the significant effects on the environment. Facts in Support of Finding The City of Pleasanton has adopted the following measures which will reduce potential impacts related to compressible soils and non-engineered fill to a less-than-significant level: Mitigation Measure 4.4-5: All existing non-engineered fill, vegetation, and soft or compressible soils and colluvium in existing canyons, creeks, stock ponds, drainages, and other areas to be graded shall be removed as necessary for project requirements. The depth of removal shall be determined by the geotechnical engineer in the field at the time of grading. Evaluation of unsuitable deposits shall be performed during grading by sampling and laboratory analysis. Significant Impact Impact 4.4-6: Fill placed during construction could settle following construction and cause structural damage. LUND RANCH II(PUD-25)RESIDENTIAL PROJECT 12 FINDINGS