FLOOD09313 - Laserfiche WebLink

Home Browse Search

Commentary on Sheet 11 ESTIMATED CONSTRUCTION COSTS Owners in this reach are the Ft. Logan National Cemetery and the City and County of Denver. Since the developments on Ft. Logan National Cemetery's property are at planning and design Stage, no major impro- vement was recommended. However, a close coordination with Ft. Logan Cemetery should be held in final design. The approximate location of the proposed Ft. Logan Reservoir is shown on this drawing. The reser- voir would reduce the 100-year flood discharge from 1,410 cfs to 1,270 cfs at Bear Creek Park. The 100-year flood boundaries with Ft. Logan Reservoir are also shown on this drawing. Item Cost I I I I I I I I I I I I I I I I I I I 2-48-inch CMP - 40 ft 12-inch CMP - 190 ft. Grass-lined Channel - 840 ft. 8 - Riprap Drop Structures 2 - 36-inch x 22-inch CMP - 20 feet Total Construction Costs $ At Kenyon Avenue, various culverts route drainage under Kenyon Avenue and into channels through the Bear Creek park. These culverts would be generally ineffective during high flows, causing the street embank- ment to backup the flow until overtopping of the road occurred. Two 48-inch CMP would be constructed at Kenyon Avenue to carry 2-year storm runoff. Major storms would overtop the roadway with a flow depth of approximately one foot. Engineering and Contingencies (35% of Construction Costs) $ Fiscal, Legal and Administrative (5% of Construction Costs) Land Acquisition Cost -1.5 acres Total Costs Annual Maintenance Cost 3,100 3,500 76,900 84,300 1,600 169,400 59,300 8,500 45,000* $ 282,200 $ 500 The existing culvert north of Kenyon Avenue in the Bear Creek park would be abandoned. A l2-inch CMP would be installed under Kenyon Avenue to divert low flow to Mullen High School for irrigation. *Most of this land is owned by the City and County of Denver. Past practice in implementing flood control projects over publicly owned lands resulted in no land acquisition costs. In Bear Creek Park, a grass-lined channel with trickle channel would be constructed to carry 10-year storm runoff. The 100-year storm runoff would be .contained in the improved channel because of the available tree board of 1.1 feet. In the vincinity of Bear Creek, the channel size would be reduced for carrying storm runoffs of less than 10-year frequency because the area would be affected by the floOding in Bear Creek. Two 36-inch x 22-inch CMP would be installed at the paved path near Bear Creek to carry low flow to Bear Creek so that the path would not be flooded as frequently as it is now.