FLOOD00689

• Designation Number: 136
• County: Arapahoe
• Community: Littleton
• Stream Name: Slaughterhouse Gulch
• Title: Major Drainageway Planning - Slaughterhouse Gulch, Littleton
• Date: 5/1/1974
• Designation Date: 5/1/1979
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Under existing channel conditions, storm water ponding was con-
sidered at one point within the basin, the Powers Park Deten-
tion Pond. The detention effect here is by design. The facility
outlet is design-optimized for the 2-year storm flood flow with
the overflow spillway designed to pass the 100-year storm flood
hydrograph. Under design conditions, the flood waters tributary
to the pond will be routed through the reservoir and released
into the conduit which proceeds downstream beneath Berry Circle.
Excess inflows will pass over the spillway and down the street
surface of Berry Circle. Some peak flood flow reduction is
experienced for each storm frequency at Powers Park. Natural
channel storage also tends to decrease peak flood flows and
attenuate the flood hydrograph. This effect, however, was not
considered in this analysis.

The final storm hydrographs at each of the design points are
enclosed to show the effect of lagging, adding and routing each
of the storm hydrographs. The hydrographs are identified as
Figures 1, 2, 3 and 4 and are at the South Platte River, main
and south tributary confluences and Powers Park, respectively.
Figure 5, Discharge Probability Curves, shows the peak flood
flows for each frequency at any location along the gulch for
both the main stream and the south tributary.

111-5