Model help:AgDegNormalFault

The CSDMS Help System


This is used to calculate aggradation and degradation of a river reach using the normal flow approximation; with an extension for calculation of the response to a sudden fault along the reach.

Model introduction

This program computes 1D bed variation in rivers due to differential sediment transport in which it is possible to allow the bed to undergo a sudden vertical fault of a specified amount, at a specified place and time. Faulting is realized by moving all notes downstream of the specified point downward by the amount of the faulting. It uses the same principles of AgDegNormal model but with extension for calculation of the response to a sudden fault along the reach.

Model parameters

Parameter Description Unit
Input directory path to input files
Site prefix Site prefix for Input/Output files
Case prefix Case prefix for Input/Output files
Parameter Description Unit
Flood discharge m3 / s
Intermittency -
Channel Width m
Grain size mm
Bed Porosity -
Roughness height mm
Ambient Bed Slope
Imposed Annual Sediment Transfer Rate from Upstream tons / annum
Length of reach m
Time step year
Number of Time Steps per Printout
Number of printout
Upwinding coefficient (1 = full upwind, 0.5 = central difference)
Coefficient in Manning-Strickler Resistance Relation
Coefficient in Sediment Transport Relation
Exponent in Sediment Transport Relation
Critical Shield stress
Fraction of bed shear stress that is skin friction
Submerged specific gravity of sediment
Height of faulting m
Fraction of reach length such that all points downstream undergo downward faulting -
Time from beginning of calculation at which faulting occurs yrs
Parameter Description Unit
Model name name of the model -
Author name name of the model author -

Uses ports

This will be something that the CSDMS facility will add

Provides ports

This will be something that the CSDMS facility will add

Main equations

Use the same equations as AgDegNormal model


The sediment is assumed to be uniform with size D. All sediment transport is assumed to occur in a specified fraction of time during which the river is in flood, specified by an intermittency. A Manning-Strickler formulation is used for bed resistance. A generic relation of the general form of that due to Meyer-Peter and Muller is used for sediment transport. The flow is computed using the normal flow approximation.

If the channel slope is negative and the water depth is not a number, “nan”, check the time step and the spatial step length. In particular, the time step may be too large or equivalently the spatial step length may be too small. Change these values and run the model again.


An example run with input parameters, BLD files, as well as a figure / movie of the output

Follow the next steps to include images / movies of simulations:

See also: Help:Images or Help:Movies


Gary Parker


  • Paola, C., Heller, P. L. & Angevine, C. L. 1992 The large-scale dynamics of grain-size variation in alluvial basins. I: Theory. Basin Research, 4, 73-90.
  • Meyer-Peter, E., and Müller, R. 1948 Formulas for bed-load transport. Proceedings, 2nd Congress International Association for Hydraulic Research, Rotterdam, the Netherlands, 39-64.