FLOOD09224

• County: Statewide
• Basin: Statewide
• Title: Steep Channel Water Surface Profiles
• Date: 7/1/1971
• Prepared By: CSU
• Floodplain - Doc Type: Educational/Technical/Reference Information

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Cross-sectional boundaries may be altered by changing stationing

in any of ~he cross-section cards. Initially, some thought was given

to providing a method, in the computer, of carrying out encroachments
into the channel, working toward a limit imposed by a given stage or
velocity. However, experience with providing encroachments manually
by simply changing cross-sectional station data indicated that such
an iterative process could not be as economically accomplished on the

computer as by longhand. The computer would have to increment by

small amounts and check the ~nergy equation after each incrementation;

whereas an encroachment line could be estimated from a map, coordinates

of the toe of the encroachment determined, and two points substi~uted

into the cross-sectional stationing to define the encroachment. A

check run on the computer to verify the trial encroachments would

indicate the accuracy of the estimate and points could be modif~ed

as necessary.

If desired, account could be taken of incremented discharge by

the insertion of an additional discharge card subsequent to the

stationing cards at the station where discharge was incremented. Such

a problem was not encountered in the study, but the point is presented

here since the process is available. For the situations encountered,

there appears to be ample availability for entry of pertinent data in
the four types of data cards.
Output data is provided on a format of two sets of columnar entries

for each station. The first set of entries is data on area, conveyance,

and top width for specified increments of water surface elevation.

The second set of entries gives solutions of water surface elevations,

velocities and energy levels, together with information on discharge

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