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-17- <br />• <br />subject to erosion on the downstream slope. If the downstream slope <br />it to be left open for a considerable period of time, we recommend <br />providing the vegetative protection. However, if the haul road <br />is to be constructed on the downstream side of the embankment in <br />the near future then no downstream slope protection will be <br />necessary. <br />Overbuild <br />We estimate settlement of the foundation soils to be on the <br />order of 8 to 12 inches under the maximum section of the embankment. <br />To allow for variation in the soil properties, we suggest that a <br />minimum of 3 feet of overbuild be provided to allow for long-term <br />• settlement. In our opinion, 3 feet of overbuild will provide a <br />sufficient margin to include both the effects of foundation and <br />embankment consolidation. Overbuild should be a maximum at the center <br />of the structure and should slope to both abutments. <br />Embankment Drain <br />The proposed embankment section includes an embankment drain <br />in the downstream portion of the embankment. The drain serves to <br />collect and discharge the seepage, as well as to lower the phreatic <br />line developed during steady state seepage. The location of a steady <br />state seepage line in this structure is questionable, considering <br />the nature of the materials and the presently anticipated design <br />life of the structure. However, if for any reason the structure should <br />• <br />