Agenda - Public Works Committee - 11/20/2007

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PROPOSED IMPROVEMENTS It is proposed that the roadway be'regarded such that it is aligned within the center ofthe 66 foot right of way. A 28 foot wide bituminous pavement shall consist of four inches of class 5 granular base, two inches of bituminous base course, and 1.5 inches of bituminous wear course on 163 rd Lane, Uranimite Street, and 164th Lane. Because of questionable soils identified on portions of Sapphire Street and 164 th Avenue the pavement structure on these streets shall consist of six inches of class 5 granular base, two inches of , bituminous base course, and two inches of bituminous wear course on these streets. Drainage shall be provided through graded roadside ditches and new driveway culverts over the majority of the project length; however, in an effort to avoid tree impacts it is proposed that a bituminous berm curb be placed along 163rd Lane and the southernmost 400 feet ofUranirnite Street. Drainage shall be conveyed from the southeast portion of the project area to the Varolite Street ditchline. Drainage from the southeast portion of the project area shall be conveyed to County Ditch 3/66 which cro&ses 164th Avenue between Sapphire and Quartz Street. Drainage from the majority ofthe project area shall be conveyed to the wetland which is located south of 164th Lane and east of Sapphire Street. Figure 2 illustrates the proposed drainage patterns including curb lines, spillways, ditches and culverts. It should be noted that 16421 Sapphire street has a mound septic , system which is located at least partially within the right of way of Sapphire Street. The proposed drainage plan eliminates the need for a ditch section past this location to avoid conflict with this system. Disturbed turfed areas shall be restored with fertilizer, seed and mulch. ESTIMATED COSTS Tlie construction cost for this project is estimated to be $200,595 of which $10,300 will be charged to the City Storm Water Utility for storm water improvements that will address existing drainage problems. Appendix B identifies detailed project construction costs and the distribution between project assessable costs and those to be financed through the storm water utility. In addition to the estimated construction costs an additional 25% has been included to cover the overhead cost associated with this project. These costs include; engineering design 8%; project administration 5%; bonding and legal 2%; inspection and testing 5%; and 5% for contingencies. The total project cost for this project is therefore estimated to be $250,744 with $237,869 being assessed and $12,875 being funded through the storm water utility. ~ '2.,'''' 27