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 2 DISCUSSION

B. Storm Sewer
I. 54" RCP (410 L.F.)...............................................$ 47,200
2. 60" RCP (290 L.F.)...............................................$ 40,600
3. 66" RCP (840 L,F.)........................................ ..... ..$142,800
4. 48" x 76" RCP (290 L.F.).........................................$ 60,900
5. 58" x 91" RCP (170 L.F.).........................................$ 51,000
6. Manholes/Vaults (10).............................................$ 25,000

7. Inlets (10).........."...........,.......,......................$ 20,000

The improvements shown on this sheet consists of a system of 54-inch and 42-

inch RCP parallel to the existing storm sewer system. The existing capacity of

the system is approximately half the 5-year storm values and is more cost effec-

tive to augment the existing system compared to replacing the sewer entirely. The

parallel design will require large vaults at the manhole locations with special

shaped inverts and deflectors to minimize transition and bend losses. At the

ourfall to Powers Park, an outlet structure similar to the one presently in place

will be required.

C. Utility Relocation (2100 L.F.)..................................,....$ 12,600

SUB-TOTAL $444,200

The existing 42-inch RCP upstream of Littleton Boulevard should be replaced

with a single larger HERCP because of lack of capacity right-of-way constraints,

and potential utility conflicts.

Contingency (15%)................... 66,300

Legal and Administrative (5%).... 22,200

Most of the pipe in this reach will be under outlet control with the HGL above

the crown of the pipe. This is caused by the backwater effect of the 5-year water

surface at Powers Park and the relatively flat sewer slopes required to avoid uti-

lities.

SUB-TOTAL $532,700

Engineering (15%)................... 79,900

TOTAL CONSTRUCTION COST $612,600

The entire reach shown on the Sheet 2 is characterized by a high concentration

of existing utilities which severely restricts the alignment of the proposed storm

sewer. There is little information about the locations and depths of the existing

sanitary sewers in this area. Prior to any design, these utilities must be carefully

and accurately located.

D. Annual Operation and Maintenance (2100 L.F.)........ .................$ 12,600

Cost of Proposed Improvements

A. Powers Park
J. Spillway Improvements.....",.,.."........,.....................$ 28,000

2. Outfall Structure.... ,...,.......,...............................$ 5,000

3. Low Flow Channel (400 L.F.)............,.........................$ 12,000

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I