FLOOD09312

• Designation Number: 370
• County: Crowley
• Community: Ordway
• Stream Name: Local Drainage
• Basin: Arkansas
• Title: Floodplain Study and Master Drainage Plan - Ordway, Colorado
• Date: 6/1/1987
• Designation Date: 7/1/1994
• Floodplain - Doc Type: Floodplain Report/Masterplan

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29

IV. EVALUATION OF ALTERNATIVES
Using the hydrologic and hydraulic data developed for the Planning Area,
alternative drainage plans were examined to address the current and future
drainage problems. Several conceptual plans were developed to assist in
arriving at their relative advantages and disadvantages. The general classi-
fication of concepts examined include:

1. Conveyance of stormwater through historic flow paths.

2. Diversion of storm flows around flood prone areas.

3. Detenti on of storm flows.

Full Conveyance, Historic Path
The need to examine this type of concept is based primarily upon Colorado
drainage law. Under current law, the liability for damages occurring to
publ ic or private property is not transferred to upstream contributors, as
long as no diversion of flood waters from historic paths has occurred, or any
changes in total flow rate and volume has been affected by the upstream 1 an-
downers. The fl oodp 1 a in presented on Fi gu re 6 has been detenni ned by ca 1 cu-
lating the peak rate of flow along historic paths, and then estimating the
width and depth of the flood waters from existing topographic data.
Conveyance of existing flows along historic paths by means of pipes or chan-
nels in and of itself is not necessary, and in fact, no action would represent
the "do nothing" alternative. The need to convey these flows in a more
orderly fashion arises when development within the Town alters the historic
outfall points, and increases the rate of runoff on a per acre basis.
With respect to the Eastern Flow Path, the existing facilities are ade-
qua te to prevent most 1 oca 1 fl oodi ng probl ems, wi th the excepti on of the box
culvert under the railroad. However, the development of the RGF and school
site properties would increase the peak rate of flow and volume to a point
where the existing storm drainage facilities and flow paths will be over-
topped. Flooding within the areas bounded by Highway 71, Railroad Avenue,
Lake Street, and 4th Street could result from overflows moving directly south
from the RGF property, and collecting along the railroad embankment. In order
to eliminate this potential, large diameter storm sewers and/or channels would
have to be constructed along Fourth, Sixth, and Ninth Streets within the

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