TRAP.TXT
                  TRAPEZOIDAL CHANNEL PROGRAM


TRAPEZOIDAL CHANNEL PROGRAM DOCUMENTATION:  Written in house using
Manning's equation and standard step backwater procedure.


PURPOSE:

To calculate:

    1.  Normal depth and velocity.
    2.  Critical depth and velocity.
    3.  Run water surface profiles.

EXAMPLE:

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######### NORMAL & CRITICAL DEPTHS FOR A TRAPEZOIDAL CHANNEL ##########
          ==================================================



NORMAL AND CRITICAL DEPTHS FOR A TRAPEZOIDAL CHANNEL


ENTER DISCHARGE,Q, IN CFS?  400
ENTER MANNINGS N?  .035
ENTER CHANNEL SLOPE, FEET/FEET.?  .005
ENTER BOTTOM WIDTH IN FEET?  8
ENTER LEFT SIDE SLOPE,  (X1):1? 3
ENTER RIGHT SIDE SLOPE, (X2):1? 3
IS DATA CORRECT?  YES=0 NO=1?  0

If NO, (enter 1) then P.C. will ask the above questions over.
Assume that the above trapezoidal channel extends 340 feet upstream of a
culvert with a headwater of 5.5 feet and we would like to find the
depth and the velocity of the channel at 340 feet upstream of the
culvert.  Use 5.5 feet as the initial depth and 3.86 (normal depth) as
the final depth.
                              P.C.'s OUTPUT

$$$$ INPUT DATA $$$$
DISCHARGE       =    400 CFS   MANNING'S N       =  0.035
SLOPE           =0.00500       BASE WIDTH        =    8.0 FT
LEFT SIDE SLOPE =  3.0         RIGHT SIDE SLOPE  =   3.0

NORMAL DEPTH    =  3.86 FT         NORMAL VELOCITY  =  5.28 FPS

CRITICAL DEPTH  =  2.98 FEET       CRITICAL VELOCITY =   7.92 FPS


####### WATER SURFACE PROFILE #######################

$$$$ INPUT DATA $$$$
   INITIAL DEPTH = 5.5 FINAL DEPTH = 3.86 INCREMENT = 0.1

///// OUTPUT /////
AN M-1 CURVE, CONTROL IS DOWNSTREAM

 DEPTH    VEL     DELTA    SUM OF      WAT     AREA    WET    HYD
  FEET    FPS     X  FT    X'S,FT     SURF    SQ FT    PER    RAD
  5.50   2.97                         41.0    134.8   42.8   3.15
  5.40   3.06     -23.4    -23.4      40.4    130.7   42.2   3.10
  5.30   3.16     -23.9    -47.3      39.8    126.7   41.5   3.05
  5.20   3.26     -24.3    -71.6      39.2    122.7   40.9   3.00
  5.10   3.37     -24.9    -96.5      38.6    118.8   40.3   2.95
  5.00   3.48     -25.6   -122.1      38.0    115.0   39.6   2.90
  4.90   3.60     -26.4   -148.4      37.4    111.2   39.0   2.85
  4.80   3.72     -27.3   -175.8      36.8    107.5   38.4   2.80
  4.70   3.85     -28.6   -204.3      36.2    103.9   37.7   2.75
  4.60   3.99     -30.1   -234.5      35.6    100.3   37.1   2.70
  4.50   4.13     -32.2   -266.6      35.0     96.8   36.5   2.65
  4.40   4.29     -35.0   -301.6      34.4     93.3   35.8   2.60
  4.30   4.45     -38.9   -340.5      33.8     89.9   35.2   2.55
  4.20   4.62     -45.0   -385.5      33.2     86.5   34.6   2.50
  4.10   4.81     -55.5   -441.1      32.6     83.2   33.9   2.45
  4.00   5.00     -77.6   -518.6      32.0     80.0   33.3   2.40
  3.90   5.21    -152.5   -671.1      31.4     76.8   32.7   2.35
  DEPTH HAS INCREMENTED ACROSS NORMAL OR CRITICAL DEPTH

The above water surface profile started at 5.5 ft. and continued
upstream (M-1 curve, sub-critical regime) and at 340 feet upstream
it computed a depth and a velocity of 4.30 ft. and 4.45 fps
respectively.