FLOOD03463

• Designation Number: 72
• County: Adams
• County: Arapahoe
• County: Douglas
• Community: Denver Metro Region
• Stream Name: Van Bibber Creek
• Basin: South Platte
• Title: Major Drainageway Planning - Van Bibber Creek
• Date: 3/1/1977
• Designation Date: 7/1/1977
• Floodplain - Doc Type: Floodplain Report/Masterplan

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- SUMMARY -

the location of the one reservoir upstream of Ward
Road will greatly enhance the degree of flood control
and protection and reduce the frequency of flooding
to the City of Arvada from high intensity rainstorms
occurring in the upper part of the basin, or that
part of the basin upstream of the reservoir. This
plan will also provide many benefits along Ralston
Creek due to reduced flooding, not accounted for in
this report.
3. By prvoiding protection from the lOa-year flood, this
plan greatly reduceS the potential flood damage
through the expansive commercial area downstream of
Kipling Street.
4. The plan calls for limited channel improvements
through the publiclY owned County Maintenance Yard.
The plan encourages the elimination of the conduit
through this reach of the channel, and promotes future
consideration of channelization and park related
development through the reach. Such improvements
would reduce expected flooding through the downstream
plaza area.
5. The plan provides the -least costly solution to the
flooding problems in both Arvada and Jefferson County.
6. The plan provides the maximum ratio of benefit to
cost in both entities.

This report represents the culmination of many studies concerned
with the flooding potential on Van Bibber Creek. The studies
have included hydrologic studies, hydraulic studies, soils
studies, potential flood damage studies, legal evaluation,
flood plain improvement studies and cost evaluations.

The primary objective of all the studies was to develop feasible
alternatives for consideration by the City of Arvada and Jefferson
County, as well as the Urban Drainage and Flood Control District,
for possible implementation to eliminate the existing and increasing
flood hazards associated with van Bibber Creek. Preliminary design
has been completed for one of these alternatives and is included
as a part of this report.

The plan selected consists of a major flood control reservoir

located upstream of Ward Road as well as various drainageway

improvements consisting of enlarged culverts, protective dikes

and embankments, flood proofing, and minor channelization and

velocity control structures in the reaches upstream and downstream

of the proposed reservoir. This plan does not propose any

enlargement or alteration to the existing concrete conduit which

traverses the lower reaches of the stream through the Arvada Plaza

commercial area.

Certain facts and figures are tabulated below to provide justifi-
cation and rationale for the selection of this plan as the
recommended drainageway plan.

1. This plan has a substantial impact on the lOa-year
flood flow through the City of Arvada, reducing
the peak flood flow from 3450 cfs to approximately
1100 cfs at the confluence with Ralston Creek.
2. Even though this studY considers the effects of the
lOa-year storm over the entire Van Bibber Creek basin,

The present worth of benefits for the City of Arvada is
$3,160,000, while the total net benefits for Jefferson County
amounted to $5,967,000. These figures lead to a benefit cost
ratio for the City of Arvada of 1.07, for Jefferson County,
3.94, and a total benefit cost ration of 2.04, thus justifying
the project from an economic standpoint.