FLOOD08495

• County: Statewide
• Community: Statewide
• Basin: Statewide
• Title: Methodology for Evaluation of Feasibility: Multijurisdictional Urban Drainage and Flood Control Projects
• Date: 2/1/1977
• Prepared By: UDFCD
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Decision Units, then decisions regarding the dams can be made
based on total damages prevented by the dams themselves,
4. Screening to Identify Most Promising Alternatives in Each
Decision Unit. Table 11-7 displayed seven Decision Units, each of
which required evaluation under one, two or three combinations of
upstream dams. If four flow frequencies are considered for design,
there will still be an excessive number of calculations required for
complete evaluation.
The screening of alternatives is very much an art and requires
engineering judgment in consultation with decision makers, In this
case, because of the possibility of using dams, the screening is more
complex.
An exact screening prescription cannot be given because of the
complexity. It is suggested, however, that the alternatives for the
Decision Units be screened first under the No Dams case. After
evaluation of this situation is completed, then the 2 Dams and 6 Dams
cases should be evaluated for comparison. Only a step-by-step
methodical process will find the best solution in every case.
5. Study of Variation of Costs and Benefits with Design
Frequency. By now it is apparent to the reader that the formulation
of alternatives is a complex task. For purposes of this example, we
will focus on a single Decision Unit. The Unit selected is reach
103-105 in the City of Englewood, Floodplain regulation is in effect
and upstream detention reservoirs will determine the flow-frequency
relationships.
The basic classes of alternatives to be considered are: