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<br />T. Haugen <br />May 6, 1986 <br />Pa ge 2 <br /> <br />We apologize for the perceived lack of follow-up inspection on the <br />geotechnical investigation. We trust this explanation resolves <br />any misunderstandings. <br /> <br />CWCS Comments (Letter dated March 26, 1986) <br /> <br />1. Paragraph 2 - Seepage flow rates were discussed on pages 13/14 <br />of the geotechni cal report, and control measures on pages <br />9/10. Some recommendations were brief because the alterna- <br />tives for seepage control and other details of the underdrain <br />were included in Muller's report. Specific materials details <br />and specifications will be included in the contract documents. <br /> <br />2. The unit cost for riprap and bedding will be re-evaluated for <br />the final opinion of probable construction cost based on the <br />latest available bid pricing information. <br /> <br />3. Paragraph 4 - A Manning's roughness factor of 0.012 was used <br />, to determine channel velocities needed for riprap design <br />because of the possibility of changes in the river bed fonn <br />due to large stage increases at higher frequencies. Changes <br />in the ri ver bed fonn are common in sand bed channel s at hi gh <br />stage. More information and justification is included on page <br />6 of the preliminary design report. We suggest this roughness <br />factor not be changed significantly. <br /> <br />4. Paragraph 5 - The design contract required that a project be <br />designed that is estimated to be buildable within the funds <br />available for construction for Phase I, approximately <br />$550,000. The decision as to which improvements are included <br />must now be made and direction given. The Preliminary Design <br />Report gives our opinion of the priorities for construction. <br />I f additional construction monies can be arranged, we would <br />recommend the total project length be designed and <br />constructed. To complete the design for the entire project <br />length would require the preparation of additional <br />construction drawings and more engineering work than we agreed <br />upon in December. <br /> <br />Corps of Engineers Coininents (Letter dated April 4, 1986) <br /> <br />1. The computer printout contained in the preliminary report <br />showed the channel fl ow rate instead of the total flow rate. <br />This gave the appearance that the total flow rate of 10,900 <br />c fs was not used for the enti re 1 ength. The water surface. <br />profl1 es were based on the full 10,900 cfs and no Change is' <br />needed. / <br />