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Summary of SEDDISCH

       seddisch - Computation of fluvial sediment discharge

       SEDDISCH computes fluvial sediment discharge by allowing the user to
       choose between five described bedload formulas and eight described
       bed-material formulas.  The bedload discharge formulas are those of
       Schoklitsch (1934), Kalinske, Meyer-Peter and Muller (1948),
       Rottner, and Einstein.  The bed-material formulas are those of
       Laursen, Engelund and Hansen, Colby, Ackers and White, Yang sand
       formula, Yang gravel formula, Einstein, and Toffaleti.

       Numerous sediment-discharge formulas have been proposed in
       literature.  Selection of the thirteen formulas used in SEDDISCH was
       based on: (1) theoretical background, (2) extent of testing by
       original author and independent investigator(s), and (3) extent of
       use by engineers and researchers.  The user is asked to choose from
       these formulas based on which field data are available.

       Bedload Discharge Formulas

       Bedload discharge is the discharge of sediment that moves in
       essentially continuous contact with the bed.

          Schoklitsch developed a bedload formula based mainly on Gilbert's
          (1914) flume data with median sediment sizes ranging from 0.3 to
          5 mm.  The basis for this formula is that bed material begins to
          move at some critical discharge and that the bedload discharge is
          proportional to the rate of work done by the part of the tractive
          force in excess of that needed to overcome the resistance along
          the wetted perimeter.

          The formula developed by Kalinske for computing bedload discharge
          of unigranular material is based on the continuity equation which
          states that the bedload discharge is equal to the product of the
          average velocity of the particles in motion, the weight of each
          particle, and the number of particles.

          Meyer-Peter and Muller developed an empirical formula for the
          bedload discharge in natural streams.  The computer program
          computes the effective diameter of the bed-material mixture from
          the entered sediment size-fraction data.  However, the program
          does not compute the bedload discharge by size fractions.

          Rottner developed an equation to express bedload discharge in
          terms of the flow parameters based on dimensional considerations
          and empirical coefficients.  In his derivation, wall and bed form
          effects were excluded, and Rottner stated that the equation may
          not be applicable when small quantities of bed material are being

          The bedload relation developed by Einstein is derived from the
          concept of probabilities of particle motion.
       Bed-Materal Discharge Formulas

       Bed-material discharge is the discharge of sediment which is derived
       from and readily exchanges with the particles in the bed material;
       particles comprising the bed-material discharge move both as bedload
       and in suspension.
          The equation developed by Laursen to compute the mean
          concentration of bed-material discharge is based on empirical
          relations using natural sediments with a specific gravity of
          2.65, and medium diameters that range from 0.011 to 4.08 mm.

          Engelund and Hansen applied Bagnold's (1966) stream power concept
          and the similarity principle to derive a sediment transport
          equation.  This equation can be used with moderately sorted bed
          materials having mean fall diameters larger than 0.15 mm.

          Colby presented a graphical method to determine the discharge of
          sand-size bed material that ranged from 0.1 to 0.8 mm in water at
          a temperature of 15.6 degrees Celsius.  This program uses a set
          of equations derived by Carl Nordin (U.S. Geological Survey) that
          represent Colby's curves at 0, 5, 10, 15.6, 20, 30, and 40
          degrees Celsius.

          Ackers and White developed a general sediment-discharge function
          in terms of three dimensionless groups: size, mobility, and

          Yang derived an equation to compute concentration of the bed-
          material discharge, for sand-bed streams, based on dimensional
          analysis and the concept of unit stream power.  He defined unit
          stream power as the rate of potential energy dissipated per unit
          weight of water, which is expressed by the velocity and slope

          Yang, using the same dimensional analysis and multiple regression
          methods as was used to derive discharge rates in sand-bed
          streams, derived an equation to compute the bed-material
          discharge concentration, in gravel-bed streams.  The same
          definition of unit stream power is used in both the sand and
          gravel transport equations.

          Einstein's method combines his computed bedload discharge with a
          computed suspended bed-material discharge to yield the total bed-
          material discharge.

          Toffaleti's method is based on the concepts of Einstein with
          three modifications: (1) velocity distribution in the vertical is
          obtained from an expression different from that used by Einstein;
          (2) several of Einstein's correction factors are adjusted and
          combined; and (3) the height of the zone of bedload transport is
          changed from Einstein's two grain diameters.  Toffaleti defines
          his bed-material discharge as total river sand discharge even
          though he defines the range of bed-size material from 0.062 to 16

       Version 1.2 1998/01/16 - First release of original program as ported
          and after code clean-up for use on UNIX workstations.

       Input for SEDDISCH is generated during an interactive session using
       the program DISDATA.  DISDATA generates a direct access file that is
       read by SEDDISCH.  The following data are prompted for by DISDATA to
       form the SEDDISCH data set:
            measurement location
            top width
            mean depth
            mean velocity
            water-surface slope
            water temperature
            particle size, in millimeters, at which the 35, 50, 65, and 90
               percent by weight is finer (enter zero if not required)

       Bed-material particle size data are entered depending on the value
       of the option code selected at the start of the run.  One option is
       that no size distribution data are to be entered.  Zero values are
       given to the percent-in-class variables for the size fractions.  The
       other two options are to enter the size data as percent-finer values
       or as percent-in-class values.

       SEDDISCH is written in Fortran 77.  Generally, the program is easily
       installed on most computer systems.  The code has been used on UNIX-
       based computers and DOS-based 386 or greater computers having a math
       coprocessor and 1 mb of memory.

       Stevens, H.H., and Yang, Chih Ted, 1989, Summary and use of selected
          fluvial sediment-discharge formulas: U.S. Geological Survey
          Water-Resources Investigations Report 89-4026, 121 p.

       Operation and Distribution:
          U.S. Geological Survey
          Hydrologic Analysis Software Support Program
          437 National Center
          Reston, VA 20192

       Official versions of U.S. Geological Survey water-resources analysis
       software are available for electronic retrieval via the World Wide
       Web (WWW) at:


       and via anonymous File Transfer Protocol (FTP) from:

         (path: /pub/software).

       The WWW page and anonymous FTP directory from which the SEDDISCH
       software can be retrieved are, respectively:


       disdata(1) - Data entry program for seddisch
       mepdata(1) - Data entry program for modein
       modein(1) - Total sediment discharge program using modified
                   Einstein procedure
       sedsize(1) - Particle-size statistics of fluvial sediments
       sizedata(1) - Data entry program for sedsize

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