# Excessive erosion and deposition

**URL:** <https://opentelemac.org/forum/t/excessive-erosion-and-deposition/7896>\
**Category:** GAIA / SISYPHE\
**Created:** [January 7, 2025, 6:14am UTC](https://opentelemac.org/forum/t/excessive-erosion-and-deposition/7896 "2025-01-07T06:14:47Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![user\_17006](https://opentelemac.org/forum/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@user\_17006](https://opentelemac.org/forum/u/user_17006)\
**Post date:** [January 7, 2025, 6:14am UTC](https://opentelemac.org/forum/t/excessive-erosion-and-deposition/7896/1 "2025-01-07T06:14:47Z")

</div>

Dear [name removed]

The following files are my modeling files. I have experienced excessive erosion and deposition during modeling. Could you please help me check and give some suggestions for modification?

Best regards

/------------------------------------------------------------------/

/ Gaia in TELEMAC Version v8p4

/ GAIA STEERING FILE

/------------------------------------------------------------------/

/

/------------------------------------------------------------------/

/ COMPUTATION ENVIRONMENT

/------------------------------------------------------------------/

/

BOUNDARY CONDITIONS FILE : geo\_jwhyuanshihd\_QHBC.cli

GEOMETRY FILE :geo\_yuanshihedao.slf

RESULTS FILE : rGaia-steady2d.slf

VARIABLES FOR GRAPHIC PRINTOUTS : B,E,M,MU,N,P,QSBL,TOB

MASS-BALANCE : YES

/ DEBUGGER : 0 / optionally enable

/

/ NUMERICAL OPTIONS

/------------------------------------------------------------------/

FINITE VOLUMES : YES

/------------------------------------------------------------------/

/

/------------------------------------------------------------------/

/ RIVERBED COMPOSITION

/------------------------------------------------------------------/

/

/ SEDIMENT

CLASSES TYPE OF SEDIMENT : NCO;NCO;NCO / CO-cohesive or NCO-non-cohesive

CLASSES SEDIMENT DIAMETERS : 0.0005;0.02;0.1 / in m

CLASSES SEDIMENT DENSITY : 2680;2680;2680 / in kg per m3

/

/ RIVERBED LAYERS - manual section 3.2.1

ACTIVE LAYER THICKNESS : 0.1 / multiple of D90 - default is 10000

NUMBER OF LAYERS FOR INITIAL STRATIFICATION : 3 / default is 1

LAYERS INITIAL THICKNESS : 100 / m - default is 100

/

/------------------------------------------------------------------/

/ BEDLOAD

/------------------------------------------------------------------/

/

/ BOUNDARIES

PRESCRIBED SOLID DISCHARGES : 0.;0.

/

BED LOAD FOR ALL [name removed] : YES / deactivate with NO

BED-LOAD TRANSPORT FORMULA FOR ALL [name removed] : 1 / MPM - see table for more

CLASSES SHIELDS PARAMETERS : 0.01;0.01;0.01

MPM COEFFICIENT : 8

/

/ BEDLOAD DIRECTION - manual sec. 3.1.4-3.1.7

SLOPE EFFECT : 1 / default is 1 - enabled

FORMULA FOR DEVIATION : 2 / use 2 for talmon-1995 approach

PARAMETER FOR DEVIATION : 1.6 / default is 0.85 - requires deviation formula 2

FORMULA FOR SLOPE EFFECT : 2 / default is 1 (koch-flokstra) change to 2 for soulsby

/ BETA : 1.3 / only with [name removed]-flokstra - default is 1.3

/ FRICTION ANGLE OF THE SEDIMENT : 20. / only with soulsby - default is 40.0 degrees

/

/ SECONDARY CURRENTS - manual sec. 3.1.7

SECONDARY CURRENTS : YES / default is no

SECONDARY CURRENTS ALPHA COEFFICIENT : 0.75 / default is 1.

/

/ FRICTION

SKIN FRICTION CORRECTION : 1 / set 0 to disable correction in shallow waters

RATIO BETWEEN SKIN FRICTION AND MEAN DIAMETER = 1. / NEW

/ BEDFORM FRICTION FOR SANDS - manual section 3.1.8

COMPUTE BED ROUGHNESS AT SEDIMENT SCALE : YES / default is NO

BED ROUGHNESS PREDICTOR OPTION : 3 / default is 1

/

/------------------------------------------------------------------/

/ SUSPENDED LOAD

/------------------------------------------------------------------/

/

SUSPENSION FOR ALL [name removed] : YES / deactivate with NO

/

/ INITIAL AND BOUNDARY CONDITIONS - manual sec. 2.1.1+2

/ INITIAL SUSPENDED SEDIMENTS CONCENTRATION VALUES : 1.E-04;0.;0.

/ PRESCRIBED SUSPENDED SEDIMENTS CONCENTRATION VALUES : 1.E-04;0.;0.

/ EQUILIBRIUM INFLOW CONCENTRATION : YES / overwrites initial values at boundaries - only when CBOR bc is 0

/

/ FORMULA

SUSPENSION TRANSPORT FORMULA FOR ALL [name removed] : 1

/

/ NUMERICAL PARAMETERS

SCHEME FOR ADVECTION OF SUSPENDED SEDIMENTS : 14

/ CONTINUITY CORRECTION : YES / use when SCHEME is 4 or 14

/ CORRECTION ON CONVECTION VELOCITY : YES / enable in deep waters

/

/ ADDITIONAL SEDIMENT - manual section 4.2

CLASSES SETTLING VELOCITIES : -9;-9;-9 / use Gaia defaults

CLASSES CRITICAL SHEAR STRESS FOR MUD DEPOSITION : 1000;1000;1000 / N per m2

LAYERS PARTHENIADES CONSTANT : 1.E-03 / in kg per m2 per s - default is 1.E-03

/ LAYERS CRITICAL EROSION SHEAR STRESS OF THE MUD : 0.01;0.1;0.1 / in N per m2

/

 ![Excessiveerosionanddeposition.png](https://opentelemac.org/uploads/default/original/2X/6/6b6b92da61107f0d9f4b72291a57cc587483cb9b.png)  
[gaia-morphodynamicsnew.cas](https://opentelemac.org/forum/uploads/short-url/tD1wOSRbZyu6TSUf8OFNa9vSb16.cas) (3.68 KB)  
[geo\_jwhyuanshihd\_BC.cli](https://opentelemac.org/forum/uploads/short-url/5fTl3fRXdvISfAVk4XfFWpg7kk2.cli) (46.7 KB)  
[geo\_yuanshihedao.slf](https://opentelemac.org/forum/uploads/short-url/z8moYkGSke9pGRrbGoe0ggoerNq.slf) (140 KB)  
[steady2d-gaia.cas](https://opentelemac.org/forum/uploads/short-url/j4VbTCnknplBru7z1WosbJR8BEQ.cas) (5.27 KB)