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Cost I I I I I I I I I I I I I I I I I I I Description of Proposed Improvements: Sheet l2 Estimated Cost of Proposed Improvements: Sheet 12 (Reaches A & B Combined) Item Description A 6'xlO' box culvert is recommended under Harlan Street, to replace the existing 5'x9.2' culvert which is too high for the proposed channel west of Harlan. Between station 66+90 and Harlan Street, it is recommended that a concrete channel with vertical walls be constructed. This channel would carry both the Dry Gulch and the North Dry Gulch flows which combine at Harlan. Although the channel in this reach has been filled and replaced with a 60-inch pipe, the re-opening of the channel should be pursued. CONSTRUCTION 6' x 10' Box Culvert Asphalt over Box Culvert Inlets Inlet Pipe Asphalt over Inlet Pipe Concrete Channel Excavation Fence Energy Dissipator Excavation for Open Channel Concrete Low Flow Channel Gabion Slope Protection Filter Maintenance Roadway Drop Structures Construction Sub-total 15% Engineering 10% contingGDCies Total Construction A concrete energy dissipator is proposed at the end of the concrete channel to "re-introduce" the flow to natural channel conditions. Downstream from station 67+00, a natural channel along the present alignment is planned. The channel is steep, with steep side-slopes, requiring drop structures to reduce the lOO-year velocity to below 7.5 feet per second. The new channel side- slopes would vary from grass-lined 4:l to concrete or gab ion lined 2:l as shown, depending upon the present setting. The maintenance access road would serve the additional purpose of a hiker-biker trail. The improvements east of station 67+00 could be considered of low priority, since no structures lie within flooded outlines, and since the existing channel appears reason- ably free from erosion damage. LAND ACQUISITION Right-of-way Acquisition Land Acquisition Sub-total 10% Contingencies 5% Legal Total Land Acquisition TOTAL COST Sheet 12 Costs in Each Reach Reach A (Denver) Reach A (Lakcwood) Reach B (Lakewood) Quantity 190 40 2 60 60 1,100 6,500 1,400 1 15,650 225 2,700 700 2,850 4 1.04 3.8 Total Canst. $ 10,270 $ 640,480 $ 97,850 Unit L.F. L.F. Ea. L.F. L.F. C.Y. C.Y. L.F. L.S. C.Y. C.Y. C.Y. C.Y. L.F. Ea. A A Unit Price $ 380 30 1,000 30 18 210 2 8 40,000 3 210 22 17 14 5,000 35,000 15,000 Land Acquisition $ 2,875 $ 98,900 $ 5,635 $ 72,200 1,200 2,000 1,800 1,080 231, 000 13,000 11,200 40,000 46,950 47,250 59,400 11,900 39,900 20,000 $598,880 89,832 59,888 $748,600 36,400 57,000 $ 93.400 9,340 4,670 $107,410 $856,010 Total $ 13,145 $739,380 $103,485