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<br />AUTOMATIC COMPUTATION OF STAGE-DISCHARGE RELATIONS AT CULVERTS 9
<br />
<br />types 1, 2, or 3 flow. Therefore, ground
<br />elevations at the ends of the approach section
<br />and the elevation" W . should be at least
<br />max
<br />as high as 2.0 D + z elevation to insure a
<br />computation. If necessary. bound the ap-
<br />proach section by fictitious vertical lines to
<br />reach this elevation. W is independent
<br />max
<br />of the H5 values on card 8. W is impor-
<br />max
<br />tant only in types 1. 2, and 3 flow where the
<br />approach section properties are used. W
<br />max
<br />is not used in types 4. 5, and 6 flow because
<br />pooled approach conditions are assumed and
<br />the approach- section properties are not re-
<br />quired. Therefore, H5-4 at 5.0 D on card 8
<br />need not be covered by W .
<br />max
<br />
<br />Columns 61-62.uNO. STA. is the number
<br />of stations used to define the approach section.
<br />It may not be less than three nor greater than
<br />25.
<br />
<br />Column 64. uNO. SA is the number of sub-
<br />areas in the approach section, and must be
<br />I, 2, 3, or 4.
<br />
<br />Column 66. --C is a choice of computation
<br />procedures. Use 0 if the stage-discharge
<br />computation is to be done; use 1 if only the
<br />approach cross- section properties are to be
<br />computed; or use 2 if approach and barrel
<br />cross- section properties are desired without
<br />the. stage- discharge computations a
<br />
<br />If 0 is used, complete cards 2 through 9;
<br />if 1 is used, complete cards 2 through 4; if
<br />2 is used, complete cards 2, 3. 4, and 9.
<br />Number the completed cards sequentially.
<br />
<br />Columns 68-72. --L . fixed decimal in col-
<br />w
<br />umn 71, is the distance from the approach
<br />section to the culvert entrance. If an ap-
<br />proach section is assumed, make L equal
<br />w
<br />to the culvert width,. h.
<br />
<br />Columns 74-78. --SEQUENCE is the card
<br />sequence number. right justified. Each line
<br />used on the form is equivalent to one card.
<br />See instructions for sequence numbers under
<br />"Preparation of Data. "
<br />
<br />Column 80. --The card number is 2.
<br />~APproach Cross-Section D::::)
<br />Data sets for five points defining the
<br />
<br />approach section can be entered on each card
<br />3. Up to five such cards can be used for a
<br />maximum of 25 points. The minimum num-
<br />ber of points is three,
<br />
<br />ST ATION is the distance, in feet. from
<br />the initial point. Standard Geological Survey
<br />practice is to locate the initial point on the
<br />left bank. List the data so that stationing in-
<br />creases in the positive direction. Negative
<br />stations can be handled. For example: A
<br />station sequence of -100, -50, -10, 20, 70,
<br />... can be computed, A sequence of laO, 50,
<br />10, - 20, -70, ... cannot be computed be-
<br />cause the stationing does not increase in the
<br />positive direction.
<br />
<br />Stations are entered in columns 1- 4. 15--
<br />18, 29-32, 43-46, and 57-60. The extremes
<br />are 9999 and - 999 feet.
<br />
<br />SA is the subarea number and must be 1,
<br />2, 3, or 4 for each station. The first station
<br />is always in subarea 1. and a 1 is used for
<br />all subsequent stations in subarea 1 if the
<br />section is not subdivided. If the section is
<br />subdivided, the last station in subarea 1 is
<br />also the first one in subarea 2 and must have
<br />a 2 as its subarea number. Similarly, the
<br />first station in subarea 3 must have a 3 as
<br />its subarea number, and tlie first station in
<br />subarea 4 must have a 4 as its subarea
<br />number.
<br />
<br />Subarea numbers are entered in columns
<br />6, 20, 34, 48, and 62. The last subarea
<br />number entered must be the same as the
<br />number on card 2, column 64.
<br />
<br />,
<br />
<br />GROUND ELEV. is the ground elevation
<br />at each station. The dotted lines represent
<br />decimal points. Every ground elevation must
<br />he carried to tcnth~ of a f\>ot -- add a zero
<br />for the tenth if neccsKary.
<br />
<br />Groun(l elevations arc enter(~d in columns
<br />B-12, 22-:H:i, 36-40, 50-!14. and H4-fiB. I':x-
<br />tremes are rl!)!)f). n amJ - nnn. n reel..
<br />
<br />Minus signs, when used for STATION or
<br />GROUN IJ ELEV.. must be in any space with-
<br />in the appropriate field, to the left of the first
<br />digit. Thus, in a GROUND ELEV. field of 5
<br />spaces, elevation -3.2 feet may be recorded
<br />as -.bb32, b-h32, or bb-32, with b represent.-
<br />ing a blank space, and with the decimal be-
<br />tween 3 and 2 implied.
<br />
<br />~
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