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e . To the extent possible, grading plans shall minimize earth-moving and <br />site-grading . Development design shall avoid placing structures and <br />utilities on or near the tops of slopes or in the shallow subsurface of <br />slopes . <br />f. The final geotechnical report for the grading plan for proposed projects <br />shall be prepared by a professional engineer and approved by the City <br />Engineer. The report shall address the potential for delayed (differential <br />settlement) consolidation within deep fills and associated land surface <br />subsidence. The report shall provide specific recommendations for: <br />• fill compaction specifications that consider the likelihood of <br />eventual saturation and wetting and drying cycles for the fill <br />materials; <br />• removal of colluvial material or weathered rock that may be <br />subject to consolidation under the load of proposed fills; <br />• design that minimizes the variability of fill thickness within fills <br />that underlie structures or other improvements at the project site; <br />and <br />• design and operation of adequate subsurface drainage systems for <br />fills (particularly beneath heavily-irrigated areas or other water <br />sources such as swimming pools or detention basins). Drainage <br />systems for fills shall be designed to minimize maintenance and <br />ensure long-term performance. Flow from the drainage system <br />shall be controlled so as not to cause or contribute to erosion of <br />existing drainage channels . <br />g. On expansive soils with moderately high shrink-swell potential (Perkins <br />loam and Pleasanton and Positas gravelly loam), building foundations and <br />improvements shall consist of drilled pier and grade beams , deepened <br />footings (extending below expansive soil), or post-tensioned slabs. <br />Alternatively, expansive soil shall be removed and replaced with <br />compacted non-expansive soil prior to foundation construction. The <br />geotechnical report for each phase of the project shall require that <br />subgrade soils for pavements consist of moisture-conditioned , lime-treated, <br />or non-expansive soil, and that surface (including roof drainage) and <br />subsurface water be directed away from foundation elements to minimize <br />variations in soil moisture. <br />h . Improvements proposed to be placed on slopes greater than ten percent, <br />or within ten feet of the tops of such slopes , shall be approved for <br />construction by a California licensed Geotechnical Engineer or California <br />certified Engineering Geologist. The City shall approve grading plans and <br />slope designs prior to implementation. <br />51