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<br />T. Haugen <br />May 6, 1986 <br />Page 4 <br /> <br />8. Clarification on the dimensions shown was requested. The <br />embankment would typically be 10 feet in height above the <br />original ground surface on the riverside. Since a river bank <br />is anticipated to exist, the landside ground surface will be 2 <br />to 3 feet hi gher. The Zone 2, shown in Fi gure 2, is maximum <br />section for this zone. The actual size of the Zone 2 may be as <br />shown or smaller than the area shown. The sudden drawdown case <br />for stability analyses was not analyzed since it was <br />anticipated that the embankment would not become saturated due <br />to a flood stage lasting only a week or two and the majority of <br />the time the water would not be at maximum river level. <br />However, with the hi gh factors of safety for end of <br />construction and steady state seepage, the sudden drawdown <br />factor of safety would be greater than 1.0. <br /> <br />An embankment height of 12 feet was used in the stability <br />analysis and a typical height of 10 feet was shown on Figure 2. <br />,The materi al properti es shown in the report are based on the <br />laboratory test results, Chen's experience and a review of the <br />literature. The in-place density values were based on the <br />Proctor compaction tests conducted and the values obtained for <br />the materials were generally similar. Chen anticipates the <br />silty materials will have some cohesion and a value of 200 psf <br />was selected for the steady state stability analyses. <br /> <br />9. Chen recommended the materials be placed at plus or minus 3% of <br />optimum moi sture content and the Corps has recommended the <br />material be placed at plus or minus 2% of optimum moisture <br />content. Chen feels construction within 3% of optimum moisture <br />content is satisfactory. Acceptable moisture-density <br />relationships should be developed during construction materials <br />testing. <br /> <br />10. We concur with this recommendation and it will be incorporated <br />into the final design. <br /> <br />11. This recommendation would add approximately 10% to the riprap <br />and bedding quantities and costs. We do not feel that the <br />additional cost adds much more value when a top riprap <br />elevation of one foot above the 100-year water surface is <br />provided. This improvement could be left for a future upgrade <br />by the Corps of Engineers, at their option and expense. We do <br />not feel that the additional riprap, installed to the top of <br />the levee, is beneficial to the City, based upon the current <br />design criteria. <br /> <br />The recommendations contained in this response to the review comments <br />are our suggestion of how to handle these questions. The City and <br />County may have other ideas or budget constraints that can affect <br />