FLOOD06423

• County: Statewide
• Community: State of Colorado
• Basin: Statewide
• Title: Preparation of Input Data for Automatic Computation of State-Discharge Relations at Culverts
• Date: 1/1/2000
• Prepared By: Matthai, Stull, Davidian
• Floodplain - Doc Type: Educational/Technical/Reference Information

16

TECHNIQUES OF WATER-RESOURCES INVESTIGATIONS

Systems Codes

welted perimeters. This is done by assign-
ing a separate subarea to the vertical section
when listing card 3, whether the vertical is
on the left side, right side, or both sides of
the subsection. Because a vertical line be-
tween two points has no area (no width) be-
tween the two points, the effect of this action
is to eliminate conveyance for the subarea
defined by the two points.

Nonstandard Conditions

The general computer program was not
designed to compute headwater elevations for
all conditions possible in the field. Do not
use the computer program if the entrance is
partly blocked by debris, ice, or snow, if
there is a break in slope within the culvert
barrel, or if the culvert has an alluvial nat-
ural bottom. Routing methods may be used
or assumptions made that are peculiar to the
site under study to determine the information
necessary for a stage-discharge relation.
For barrels that vary in size, use the mini-
mum section dimensions.

EXAMPLE

The following example of input and output
is for a 6-foot diameter corrugated-metal
pipe. 76.6 feet long with the inlet 0.99 foot
higher than the outlet, and an n of 0.025.

The input is the completed data form
(fig. 3).

The output or computer printout consists
of three parts. The first is a table of the
approach cross-section properties (fig. 4).
The second part is a table of the culvert bar-
rel properties (fig. 5), and the third is a tab-
ulation of discharges, headwater and tail water
elev~tions, depths, types of flow, and dis-
charge coefficients (fig. 6).

The output is a combination oi the compu-
tations for examples. 1. 3, 5- 8 in Bodhaine
(1 fH18). These data are used to derive the
p;tage-discharge relation plotted in figure 7.

MESSAGES

The- output sheets will occasionally haVe
nwsHagC's printed out. These will be of
tht'f"(> t~'pes: (a) systems codes, (b) input-
card errors, and (c) computational messages.
Messages in each of these categories are de-
scribed in detail below, along with explana-
tions and remedies.

Systems errors are those which res-uU
from job-control specifications or linlitations
involving the computer, and not the conlpuler
program or the input data cards.

One category of systems errors about
which something can be dOhe is that involving
the physical limits chosen on the job control
cards. The messages will appear in the job
statistics part of the printout in the first part
of the output, and give the reason for the job
not being completed. The most frequently
seen system completion codes are:

COMPLETiON CODE-SYSTEMo222......
Explanation: The operator at the Computer
Center Divisibn has cancelled the job. Check
the estimated number of lines on the job card
to be certain this number has not been exceed..
ed, thus aborting the computation. Estimate
the number of lines needed to be 200 times
the number of culverts, rounded up to the
next full thousand.

COMPLETION CODE-SYSTEMo322.....
Explanation: The time allotted to the job has
been exceeded. Increase the estimated TIME
parameter on the EXEC card. Use 2 minutes
for 1-25 culverts, and 3 m.inutes for 25-50
culverts.

~

COMPLETION CODE-SYSTEMo80A.....
Explanation: An insufficient amount of
core space necessary to run this program
has been requested. Increase the REGION
parameter on the EXEC earp to 90K.

A second category of systems errors and
messages shows up in the computational
phase of the program. These have to do with
underflow, overflow, divide checks, and
standard fixups, The stringent precomputa-
tion edit checks are designed to avoid the oc-
currence of these conditions. If, however,
such messages do appear in the output, the
reason may be that a card has been misread
or skipped. Check the aUnement of punched
holes on the cards, and be certain no cards
are bent, scratched, dog-eared, or marred.
Generally, messages of underflow, over-
flow, and divide checks should be referred
to the Computer Center Division specialist of
the terminal at which the job is submitted.

Input- Card Errors

Errors in this category will show up in the