FLOOD01888

• County: Statewide
• Title: River Hydraulics
• Date: 10/15/1993
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Educational/Technical/Reference Information

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· · · .. Observed
-Computed, levees & low n-values
- - Computed. original n-values

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River Mile

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Figure 3-3. Profile callbretion to high weter merks

similar to the "split sample" testing procedure of fre-
quency analysis. The calibrated model is used 10 com-
pute elevations from additional flood events that were not
used during the calibration process. The objective of this
test is to confmn that the calibrated model can be used
with confidence for other events. If only one or two
floods have data, insufficient information may exist for
the verification process; however, the verification step
should be part of the overall calibration process. In the
absence of data for verification, additional sensitivity
analyses should be performed 10 evaluate the potential
range of results due 10 uncertainty in input data.

3-6. Guidelines for Analytical Model Selection

The choice of appropriate analytical methods to use dur-
ing a river hydraulics study is predicated on many factors
including (I) the overall project objective, (2) the particu-
lar study objective for the project (level of detail being
called for), (3) the class, type, and regime of flows
expected, (4) the availability of necessary data, and

280

(5) the availability of time and resources 10 properly
address all essential issues. The following sections dis-
cuss the importance of these factors.

a. Study objectives. The type of analytical model
selected by the hydraulic engineer should reflect the
demands and objectives of the study. The type of model
required may not be apparent until the hydraulic engineer
becomes well-versed in the problems to be evaluated and
spends considerable time with the study manager, econo-
mist, and local sponsor, discussing problems and puten-
tiaI solutions. Much of the initial reconnaissance work
focuses on this problem. The level of detail relates
directly to the model selected, as was described in sec-
tion 3-lb. The study manager or local sponsor may
specify or request a certain level of detail that may or
may not be appropriate for the stage of the study. The
hydraulic engineer must be able to designate the level of
detail required for the problems to be studied, stage of
the study, and intelligently discuss these requirements
with the study manager, and local sponsor. It is the

3-13