FLOOD08407

• County: Jefferson
• County: Adams
• Community: Arvada, Westminster
• Stream Name: Little Dry Creek
• Basin: South Platte
• Title: Major Drainageway Planning
• Date: 4/1/1979
• Prepared For: Jefferson County / Adams County
• Prepared By: UDFCD
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

Residents in the vicinity of the 100-year floodplain should be notified annually of the
potential flood hazards. Since the improvements are designed for the 25-year event, the
continued enforcement of floodplain regulations and an ongoing program of floodplain
management will be necessary after the proposed improvements are built to compensate
for larger floods.

COMMENTARY - SHEET 16

The improved grass-lined channel is to roughly parallel the 69th Avenue right-of-

way until it intersects with the low flow crossing proposed at Irving Street. By designing

this crossing so that storm waters pass over the low traffic roadway, the need for costly

bridge construction is avoided while providing access to the maintenance road and the

area on the opposite bank.

Continuing to Federal Boulevard, the 25-year grass channel would follow approxi-
mately the historic channel, At Federal, three 10-foot by 8-foot reinforced concrete box
culverts would be constructed parallel but depressed below the existing 10' x 10' concrete

TOTAL IMPROVEMENT COSTS - SHEET 16
Item
Channel Improvements
Street Improvements
Improve Federal Boulevard Crossing
Utility Relocation

box culvert.

The two Colorado and Southern Railroad track crossings just east of Federal are to

be combined into one crossing located approximately 230 feet beyond the existing 4'

diameter culvert. The 54-inch metal pipe beneath the railroad siding is to remain,

facilitating drainage of the area west of the siding and north of the main track. The cost

of the new railroad track crossing is included in the Sheet 17 cost estimate.

SUB-TOTAL
Contingencies (25% of Sub-Total)

The presence of two separate sewer collection systems, those of the City of West-

TOTAL CONSTRUCTION COSTS
Right-of-Way Acquisition
Annual Operation and Maintenance Costs
Present Worth Operation and Maintenance Costs

minster and the Crestview Water and Sanitation District (the latter formerly known as the

Baker Metropolitan Water and Sanitation District), significantly increase the utility

relocation costs. As shown on Sheet 16, where the two sewer networks overlap, the relo-

cation efforts are complicated by the sewer line layout which tends to follow the existing
drainage channel. Additional field work is necessary to more accurately assess the utility
conflict. Significant savings may be realized during the final design by modifying the

TOTAL IMPROVEMENT COSTS

channel shape or alignment to avoid relocating these sanitary sewers.

The existing floodplain should be regulated and property owners who would be
adversely affected by the 100-year flood should be encouraged to acquire flood insurance.

Cost
$ 307,900
$ 5,800
$ 390,500
$ 97,100
$ 801,300
$ 200,300
$ 1,001,600
$ 215,600
$ (7,600)
$ 110,100

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

$ 1,327,300