FLOOD02020

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Title: Feasibility Evaluation Multijurisdictional Urban Drainage Projects
• Date: 2/1/1977
• Prepared For: UDFCD
• Prepared By: Multiple Authors
• Floodplain - Doc Type: Educational/Technical/Reference Information

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1, Decomposition into Decision Units, The Little Dry Creek

Basin contains some logical points for decomposition since there

are five local governments involved, The area breaks down neatly

into subcatchments and reaches, Table 11-1 shows the decomposition

of the basin into subcatchments, giving the stream mileage within

each subcatchment by jurisdiction, To further summarize the de-

composition by jurisdiction, Table 11-2 gives the subareas of the

basin by jurisdiction, Figure 11-3 shows the subdivision of the

basin into reaches in the form of a line diagram, The average

length of the reaches is on the order of 0,75 miles, Each reach can

now be referred to as Little Dry Cr'eek, 109-111, for example,

2, Development of Damage Redu_c.:I:.-i.Qn Da!_~. The procedure is to

build up relationships within each reach for damage versus depth of

flooding, Appendix A demonstrates how this is done, The result
should be curvets) for reaches where damage can be reduced or miti-

gated by implementing flood control measures, Figure 11-4 shows

typical curve development,

3, Formulation of Alternatives, Alternatives are formulated
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for each Decision Unit or combination thereof, The Decision Units

correspond to the reaches shown on Figure 11-2, The existence of

zoning over the 100-year floodplain is assumed for each alternative,

Because of the special conditions in the basin, combination of

the following classes of alternatives are considered:

1, Improvement of existing dams or construction of new dams

2, Natural channel s with necessary improvements

3, Improvement of existing conduits