ETL 1110-2-367
31 Mar 95
the modular input data. HEC-IFH allows the user to display the
comparison data can then be given to the economist for an
results of the specified plans side-by-side in a report called Plan
economic assessment of the flood damage reduction benefits
Comparison Summaries. For Continuous Simulation Analyses,
produced by the various plans to determine which plans are
eight summaries arranged into four categories are available.
viable features.
Figure 5-6 illustrates the plan comparison summary menu and
5-6.
Plan Performance
the eight summaries that are available. For hypothetical event
analyses, four plan summaries are available as shown in Figure
After the selection of the NED plan, the HEC-IFH program
5-7. Chapter 13 of the HEC-IFH user's manual lists all the data
should be operated for both CSA and HEA events using the
values that can be specified for both types of analyses. The most
selected components to verify the desired functional results. By
important comparison is generally the peak elevation versus the
comparing the NED plan results with other plans, the residual
percent chance exceedance frequency event. The minimum
impacts of floods with volumes larger than the NED plan can
facilities plan can easily be compared with another plan having
handle can be determined. Also, if a specific ponding area size
additional gravity capacity or with several plans having various
is required, the impacts of encroachments can be analyzed and
pumping capacities. A tabular comparison of maximum interior
the local sponsor can be made aware of the consequences of not
elevation versus frequency is illustrated in Figure 5-8 and a
maintaining this feature. The consequences of a pump unit
screen plot of that same data is shown in Figure 5-9. By looking
failing during an event should also be evaluated.
at the comparisons, a perspective is gained on the effectiveness
of additional gravity drains or pumping capacity. This
Figure 5-6. Continuous simulation plan comparison summary menu
5-12
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