2009-03-02_REVISION - M2004009 (10)

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EEC Project No. 1082030 ASC1 - Turnpike Reservoir May 5, 2008 Page 13 Earth Engineering Consultants, Inc. cohesive soils along with the underlying bedrock material will be utilized. After the design details have been determined, slope stability analyses including steady state and rapid drawn down along with seepage analyses should be performed. We suggest the proposed embankments be constructed on minimum 3:1 (horizontal: vertical) around the perimeter of the reservoir. The design of wave and slope protection for the reservoir is beyond the scope of this feasibility study and report and should be reviewed during the final design stages. Earthen Liner Improvements Due to the relatively shallow depth to groundwater and bedrock, (i.e. approximately 8 to 20- feet below existing site grades), dewatering of the pond area will be required prior to conducting any earthwork activities. It is recommended any vegetation within the limits of the pond configuration be stripped and removed. It is anticipated that excavation of the pond could be accomplished by conventional type excavation equipment; however cemented sandstone lenses may be encountered at increased depths, depending upon final depth of excavation. Areas of well-cemented sandstone bedrock lenses may be encountered throughout the site at various depths where specialized drilling equipment and/or rock excavating equipment may be required. Excavation penetrating the well-cemented sandstone bedrock may require the use of specialized heavy-duty equipment, such as a "controlled blasting protocol." Consideration should be given to obtaining a unit price for difficult excavation in the contract documents for the project. The pond should be excavated on slopes of 1:1 or flatter and the earthen lined berms/embankments should be constructed on 3:1 or flatter slopes. The berms/embankments surrounding the pond should be lined as part of the wetted perimeter with an approved earthen liner material. Approved materials used in the earthen liner/embankment should be placed in maximum 9- inch thick loose lifts, adjusted in moisture content, and compacted to at least 95% of the materials' maximum dry density as determined in accordance with ASTM Specification D- 698. The moisture of the liner materials should be adjusted to be within the range of f2% of standard Proctor optimum moisture at the time of compaction. All earthwork/compaction