FLOOD10505

• County: Morgan
• Community: Brush
• Basin: South Platte
• Title: Brush - Storm Drainage Master Plan
• Date: 7/19/2006
• Prepared For: Brush
• Prepared By: Nolte Associates, Inc.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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I'JOlTE

BEYOND ENGINEERING

City of Brush
Storm Drainage Master Plan

enter and be conveyed by the Brush Lateral which crosses 1-76 just east of the
subdivision.

The existing capacity of culverts where the Brush Lateral crosses 1-76 is approximately
40 cfs and is very limited compared to stormwater flows generated by upstream basins
that could potentially enter the ditch. Any flow in the ditch in excess of the 40 cfs
capacity will tend to collect in this area. Alternative 1 also offers an advantage in that it
could more readily serve as an outfall for drainage improvements to the 1-76/Colorado
Highway 71 interchange.

South Railroad Area
For the South Railroad Area, one alternative was evaluated consisting of construction of
additional storm sewer inlets in nearby streets and larger storm sewer along South
Railroad Street. The storm sewer discharges to Beaver Creek to the east. Total estimated
costs for this alternative are approximately $1.1 million and $1.2 million for the 10-year
and 25-year design options respectively. It should be noted that this area would appear to
be flood extensively by a flood as small as a lO-year flood on Beaver Creek and proposed
improvements would not provide any protection from flooding from Beaver Creek.

Lincoln Street/Mill Street Outfall
The Lincoln/Mill Street Outfall drains a relatively large area of approximately 264 acres
in the central portion of the city south of Mill Street (Basin 3 on the Master Plan). The
existing outfall for this basin is a 42" diameter storm sewer with a capacity of
approximately 34 cfs. The 10-year and 25-year storm discharges from Basin 3 are 177 cfs
and 247 cfs respectively and greatly exceed the capacity of the existing outfall. For the
Lincoln Street/Mill Street Outfall, two alternatives were evaluated. Altemative 1 consists
of providing additional inlets in the northern portion of the basin near Lincoln Street, Ray
Street and Mill Street and construction of large diameter storm sewers to the east and
north to discharge to the City of Brush detention facility north ofI-76. Total estimated

Nolte Associates,Inc.

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