FLOOD01117

• Designation Number: 219
• County: Arapahoe
• Community: Littleton
• Stream Name: Upper Slaughterhouse Gulch
• Title: Major Drainageway Planning - Upper Slaughterhouse Gulch
• Date: 3/1/1983
• Designation Date: 7/1/1983
• Floodplain - Doc Type: Floodplain Report/Masterplan

SHEET 3 DISCUSSION

c. Utility Relocation (2250 L.F.)..........,...............,............$ 13,500

SUB-TOTAL $689,800

The improvements shown on this sheet consist of removal of the existing storm

sewer and installation of 58" x 91" HERCP and 48" x 76" HERCP, upstream of the un-

developed area east of BroadwaY' Topographic constraints restrict the size, shape,

and alignment of the pipe. There are several existing utilities within the Broad-

way ROW, which must be verified prior to the final design. The overall proposed

storm sewer system will have an ultimate capacity equal to the 5-year flood event

after Caley detention pond is constructed. Prior to construction of Caley deten-

tion pond, the proposed storm sewer will have approximately a 2-year capacity.

Cont ingency (15%)................... 103,400

Legal and Administrative (5%)....... 34,500

SUB-TOTAL $827,700

Engineering (15%)................... 124,200

SUB-TOTAL $951,900

The 600-feet of open channel across the undeveloped area east of Broadway and

west of Grant Street will have a 5-year capacity of 146 cfs. The grass-lined

channel will have a 5-foot wide concrete low flow channel and 4: 1 side slopes. A

concrete headwall will be required at the inlet to the proposed storm sewer system.

D. Site Acquisition (0.5 Ac.)..... ,.............. .......................$ 12,500

TOTAL CONSTRUCTION COST $964,400

E. Annual Operat ion and Maintenance..................................... $ 3,600

The proposed 32" x 49" HERCP upstream of the channel will have a 5-year capa-

city of 57 cfs, which is the floodpeak from the 5-year storm sewer along Maplewood

Avenue.

Cost of Proposed Improvements

A. Open Channel
J. Channel (650 L.F.)...............................................$ 32,500

2. Structures... .... ........ .......... ........ ................ ......$ 10,000

B. Storm Sewer

I. 48" x 76" RCP (890 L.F.).................... .................... .$186,900
2. 58" x 9 I" RCP (1100 L. F . ) .. . . . . . . .. . .. .. . .. .. .. .. .. . .. .. . . .. .. . .. $ 330 ,000

3. Inlets (26)................,............".......................$ 52,000

4. Manholes (14)........,.............,..,............"............ $ 32,500

5, 32" x 49" RCP (360 L.F.)............ .............................$ 32,400

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