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<br />Description of Proposed Improvements: Sheet 15 <br /> <br />The upstream limit of the North Dry Gulch analysis was contrac- <br /> <br /> <br />tually set at Dover Street. This should not necessarily be inter- <br /> <br /> <br />preted as the limit of drainage problems in North Dry Gulch, since <br /> <br /> <br />there are frequent flooding problems in the basin west of Dover <br /> <br /> <br />Street. However, the drainage problems are intensified at this <br /> <br /> <br />location by' the relatively common overflow of storm runoff carried <br /> <br /> <br />by the Rocky Mountain Ditch. Large capacity inlet structures are <br /> <br /> <br />proposed at Dover Street to collect this overflow. <br /> <br />Numerous inlets are proposed to assure continuous collection of <br /> <br /> <br />the 10-year flow. Future laterals into the storm sewer trunk <br /> <br /> <br />line may be dictated by localized drainage problems which are <br /> <br /> <br />not addressed by this report. <br /> <br />Estimated Cost of Proposed Improvements: Sheet 15 (Reach H) <br /> <br />A 72-inch diameter storm sewer system, running generally along <br /> <br /> <br />l6th Avenue, is proposed. While the surface flow diverges from <br /> <br /> <br />the pipe alignment, the utilities and traffic make construction <br /> <br /> <br />on Colfax Avenue undesirable. The provision of the storm sewer <br /> <br /> <br />shown will reduce surface flows reaching Colfax, and thus assure <br /> <br /> <br />its available use as an arterial street in emergency situations. <br /> <br />Item Description <br /> <br /> <br />CONSTRUCTION <br /> <br /> <br />72" Storm Sewer <br /> <br /> <br />Asphalt over 72" Pipe <br /> <br /> <br />Manholes <br /> <br /> <br />Inlets <br /> <br /> <br />Inlet Pipes <br /> <br /> <br />Asphalt over Inlet Pipes <br /> <br /> <br />Construction Sub-total <br />15% Engineering <br />10% Contingencies <br />Total Construction <br /> <br />Quantity <br /> <br />Unit <br /> <br />Unit Price <br /> <br />Cost <br /> <br />2,800 L.F. $ 160 $448,000 <br />2,800 L.F. 24 67,200 <br />8 Ea. 1,000 8,000 <br />23 Ea. 1,000 23,000 <br />690 L.F. 30 20,700 <br />690 L.F. 18 12,420 <br /> $579,320 <br /> 86,898 <br /> 57,932 <br /> $724,150 <br /> <br />Under present conditions, surface flows on North Dry Gulch in <br /> <br /> <br />storms of 5-year magnitude would spill southward over Colfax at <br /> <br /> <br />Balsam St. The proposed facilities would convey the lO-year flood, <br /> <br /> <br />and the remaining surface flow in a lOO-year flood would be con- <br /> <br /> <br />tained on the north side of the Colfax median between Balsam and <br /> <br /> <br />Yarrow Streets. This eliminates the flooding in Colfax Gulch <br /> <br /> <br />(south of Colfax) caused by overflow from North Dry Gulch. This <br />change is explained in greater detail in Section III. <br /> <br />LAND ACQUISITION <br /> <br /> <br />Easements along Pipe Lines <br /> <br /> <br />10% Contingencies <br /> <br /> <br />5% Legal <br /> <br /> <br />Total Land Acquisition <br /> <br /> <br />TOTAL COST <br /> <br />630 <br /> <br />L.F. <br /> <br />15 <br /> <br />9,450 <br />945 <br />473 <br />$ 10,868 <br /> <br />$735,018 <br /> <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />I <br />