FLOOD10360 ‎(2)‎

• County: Washington
• Community: Otis
• Title: Preliminary Design, SW Drainageway, Railroad to Washington Street, Town of Otis Colorado
• Date: 1/1/1997
• Prepared For: Otis
• Prepared By: McLaughlin Water Engineers, Ltd.
• Floodplain - Doc Type: Floodplain Report/Masterplan

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Reach 5, Alley at Spruce Northwest to Washington Street
From the alley at Spruce Street to Washington Street, the proposed trapezoidal channel crosses vacant land
at a diagonal to the northwest. The current landowner explained there is an old house foundation in that
area, The proposed channel would have flat side slopes to allow equipment to cross the channel.

Reach 6, Washington Street Crossing
At Washington Street, the road is proposed to be lowered approximately 3 feet, The road would have a
flat area 60 feet long and transition at 2% north and south to the existing roadway, No new culvert is
proposed to carry the low flow as the current 18-inch pipe is plugged, helping to form a lake on the west
side of Washington Street. The surface would be concrete and change to gravel to match the existing road,

Upstream of Washington Street to Dade Street, the current slope is 0,0036 percent. No work is proposed
to create an improved channel. The low area adjacent to Elm Street and the street itself will carry the
slow, Some grading can be done to improve the grade and reduce ponding,

At Dade Street the three existing culverts are plugged, They should be cleaned as a part of this project to
improve low flow, No other improvements are proposed at this time in the vicinity of Dade Street as the
backup west of Dade Street and the overtopping of the street have not adversely affected the residents,
During high flow conditions, the road may be impassable, Larger culverts and a different road grade may
be needed, but can be postponed as the higher priority area is from the Vine/Spruce intersection through
Washington Street,

The hydraulic analysis shows that the proposed system would exceed a five year frequency design level,
similar to the 1993 design, The design phase may show some improvements to increase the channel
capacity ,

PUBLIC MEETINGS

Two meeting were held at the Town to discuss the concerns of the citizens regarding the proposed channel
work and alignment. One meeting was held on December 16, 1996 and the other on January 9, 1997, One
concern raised was the possibility of a dam west of town, A cursory look at a potential dam shows a cost
near $500,000, significantly more than current available funding, In addition, a channel would be needed
through Town as there would be flow out of the dam, plus flow from tributary areas downstream of the
dam. A dam could have a positive affect on the 1oo-year flow, reducing the 1oo-year flood plain, but
would have no affect on the more frequent storms, This could result in continual flooding along
Washington and Spruce Streets as occurred in 1993, There was discussion of ways to improve drainage

96-046.OO2IPRELIM

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