# Model help:AgDegNormalSub

## AgDegNormalSub

This program is used to calculate the evolution of upward-concave bed profiles in rivers carrying uniform sediment in subsiding basins.

## Model introduction

The program computes the approach to mobile-bed equilibrium in a river carrying uniform material and flowing into a subsiding basin. It is a descendant of AgDegNormal.

## 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 -
Grain size of bed material mm
I -
Manning-Strickler coefficient, k -
Slope of forest face -
upstream bed material sediment feed rate during floods m2 / s
L -
Time step days
Iterations per each printout
Number of printout m
Number of fluvial nodes
u
Manning-Strickler coefficient, r
Coefficient in total bed material relation
Exponent in load relation
Critical Shield stress
p
Submerged specific gravity of sediment
initial length of fluvial zone m
B -
O -
Y -
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

• Exner equation for uniform sediment from a river
 $\displaystyle{ \left ( 1 - \lambda _{p} \right ) \left ( {\frac{\partial \eta }{\partial t}} + \delta \right ) = - {\frac{I_{f}}{r_{B}}} \left ( 1 + \Lambda \right ) \Omega {\frac{\partial q_{t}}{\partial x}} }$ (1)
• Ratio of depositional to channel width
 $\displaystyle{ r_{B} = {\frac{B_{d}}{B_{c}}} }$ (2)
• The maximum possible length of the fluvial reach
 $\displaystyle{ L_{max} = {\frac{I_{f} \left ( 1 + \Lambda \right ) \Omega }{r_{B}}} {\frac{q_{tf}}{\left ( 1 - \lambda _{p} \right ) \delta}} }$ (3)