FLOOD06837

• County: Alamosa
• Community: Alamosa
• Stream Name: Rio Grande
• Basin: Rio Grande
• Title: Master Drainage Plan Alamosa
• Date: 3/1/1982
• Prepared For: Alamosa
• Prepared By: McCarty-Hurst
• Floodplain - Doc Type: Floodplain Report/Masterplan

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VI. PROPOSED ALTERNATIVE SOLUTIONS
A. BASINS I THROUGH VIII

Favorable alternatives that appear feasible and that will reduce or
eliminate the flooding problems in the Alamosa area, as discussed in
the previous section, are presented in a basin-by-basin basis herein.
The reader should cross reference the discussion of alternatives with
Figure 2 for the location of drainage basins, design points, and pro-
posed alternatives. Alternatives not reported were investigated and
eliminated from further consideration as they were judged impractical
or cost-prohibitive. One alternative considered was large grass-lined
or concrete-lined channels. These are not practical because of high
right-of-way (ROW) costs and the requirement of removing buildings
that the project is intending to protect.

The location of the proposed sewers was also considered as an alter-
native. The sewer line proposed in 6th Street was also evaluated as
if located in the Main Street ROWand in the railroad ROW south of
6th Street. Construction in the Main Street alignment would disrupt
the main business area, the main traffic flow through the city, and
create higher costs due to limited availability of ground due to
other major utilities. Construction in the railroad area was elim-
inated because of high land acquisition costs, increased structural
loadings, and disruption of the railroad activities.

Each aiternative studied will require an outlet into the Rio Grande
River. These outlets from the storm sewer systems (inlets into the
Rio Grande) will be at or near the elevation of the bottom of the
Rio Grande. When the water rises in the Rio Grande, water will back-
flow into the city's existing and proposed storm sewer systems caus-
ing flooding. Thus each system, existing and proposed, must be
fitted with a flap gate. Flap gates allow flow to drain from the
pipe to the river but not from the river into the pipe. No separate
discussion is made for each basin regarding the use of flap gates.

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