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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second reason was that the design would not change the low area at Spruce Street and Washington Street.
The channel would cut off access to the north, and flooding would cut off access to the south, thus,
stranding some of the citizens, The 1988 project was not pursued further,

In 1993, heavy rains on the Colorado eastern plains caused flooding in several small towns, including Otis.
The area of Spruce and Washington Streets was under water for several days, The Town again requested
assistance from the State, but with a 1993 design revision. The 1993 design proposed no new railroad
culverts, a channel along the railroad to Washington Street, and a low water crossing at Washington Street.
The capacity of the 1993 design was near the 5-year stonn frequency, This smaller scale project was
estimated to be $107,000 and was approved by the State. However, the access was still cut off at the
north, and the flooding potential of the low area to the south was still a concern to the Town, After
extensive local debate, the project was rejected.

The Town again wants to pursue State funding, but following a revised alignment. The new alignment
would follow the existing low flow path upstream from the railroad to where it turns south, east of Vine
Street to Spruce Street, then west in Spruce Street past Vine Street to the alley between Vine and
Washington Streets, Then it would turn northwest across vacant land to the existing Washington Street
culvert, across a lowered Washington Street, and then west to Oak Street following the Elm Street
alignment, then southwest to Dade Street. The proposed project funding would be from the State of
Colorado's Community Development Block grant. The Colorado Water Conservation Board (CWCB) is
the State Office that perfonns the technical review of the designs. The CWCB has requested that the
newest proposed channel have a similar capacity to the 1993 design or greater.

PRELIMINARY DESIGN - PROPOSED SYSTEM

The existing mapping used for the 1988/1993 designs did not cover the proposed alignment. A site survey
was made in order to complete the evaluation, The bench mark used in the 1988 design was found and
used for the survey, A I-inch to 200 feet map was available, but it lacks the necessary detail, When
completed, the survey data was compared to the maps and found to correlate,

The hydrology was completed in May 1986 by Engineering Professionals, Inc, for the Town of Otis, The
flow for the SW Drainageway at the railroad culverts is 2,456 cfs for the 100 year stonn, and 1,094 cfs
for the 10 year stonn, The 5-year stonn is estimated to be 650 cfs by plotting the data given in the 1986
report and extrapolating.

The proposed alignment is shown on Figure 1, which also shows the 1988 design. The hydraulic analysis

96-Q46,OO2IPRELIM

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