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<br />'v ,~W?I Dr 2M' "no SJCD (South) ~,!,<~ DrMk<gevi?y Piclnn,n. I Update
<br />nn(t>p,...;,11 Des' Report
<br />FeDr~~ry 2006
<br />
<br />Master Plan
<br />
<br />The Master Plan takes into account four existing regional detention basins in the study area, and
<br />includes construction of a new regional detention basin on the North Tributary of Massey Draw
<br />upstream of Carr Street. Inadvertent detention that may occur throughout the study area was not
<br />taken into account. Specific on site detention and 8MP requirements were not identified that would
<br />supercede those of the rocal jurisdictions.
<br />
<br />The Master Plan improvements are intended to provide a reasonable level of protection while adhering
<br />to the Jefferson County drainage criteria, where possible. Because development has occurred along
<br />most reaches, the land requirement to construct improvements that fully conform to the criteria was
<br />considered to be excessive. Channel stabilization is recommended along most of the reaches. The
<br />stabilization will help to minimize future channel erosion, improve public safety, protect utilities and
<br />improve water quality. Culvert improvements are recommended for arterial streets to eliminate
<br />overtopping and maintain general and emergency access. On minor streets, culvert improvements are
<br />recommended if structure flooding can be eliminated or if the overtopping can be significantly reduced.
<br />At some locations, culvert improvements for minor street crossings are not recommended even though
<br />the overtopping depth exceeds the Jefferson County's drainage criteria because alternate access
<br />routes are available and the minor reduction in overtopping depth did not justify the cost of
<br />improvements. Regional detention is recommended on the North Tributary of Massey Draw, upstream
<br />of Carr Street. This parcel of land is currently undeveloped and is in the floodplain. The flow
<br />reductions that will result from the detention basin will reduce the street overtopping at Allison Street,
<br />eliminate downstream structure flooding and wilt reduce stream erosion.
<br />
<br />Select channel improvements are recommended to improve capacity and/or to eliminate vertical
<br />banks. In the Meadow Ranch area, a levee is recommended to divert the discharges in Massey Draw
<br />to the south side of West Rockland Drive, eliminating structure flooding on the north side of West
<br />Rockland Drive. In some locations, using the 2-foot contour interval project mapping, it appears that
<br />structures are located in the floodplain. It is recommended that elevation certificates be prepared for
<br />structures to determine whether they are located in the 1 DO-year floodplain
<br />
<br />The total cost of the plan is $27,345,600. The cost by jurisdiction is summarized in Table ES-4.
<br />
<br />Construction
<br />Easement Acauisition
<br />Continnencies (25%)
<br />Engineering Services (15%)
<br />Cons~r_~ctio!!_I!.Jsp~ti~n (10%)
<br />Leaal I Administration (S%)
<br />Total
<br />
<br />Table ES-4
<br />Cost Summary bv Jurisdiction
<br />Jefferson Count\.
<br />$13,806,000
<br />$5,893,000
<br />$3.451,500
<br />S2,070,9OO
<br />-- -.- ---
<br />S1,380,600
<br />S690,300
<br />S27,292,300
<br />
<br />CiN of Littleton Aranahoe
<br />SO
<br />SO
<br />SO
<br />SO
<br />$0
<br />SO
<br />SO
<br />
<br />Count
<br />S34,4oo
<br />SO
<br />~8.6oo
<br />S~,200
<br />_S~~OO
<br />S1,7OO
<br />$53,300
<br />
<br />Total
<br />S13,840.400
<br />$5,893,000
<br />S3.460, 1 00
<br />S2,076,100
<br />S1,384,OOO
<br />S692,OOO
<br />S27,345,600
<br />
<br />Table ES-S summarizes the Master Plan improvements costs and benefits by r
<br />illustrates recommended improvements.
<br />
<br />each. Figure ES-2
<br />
<br />0\
<br />
<br />ES-4
<br />
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