Sediment Component Tutorial¶

This tutorial introduces the Sediment component in rompy-xbeach, which controls sediment transport, morphological evolution, bed composition, and related processes in XBeach.

What You'll Learn¶

1. How to configure the Sediment component
2. Sediment transport formulations and calibration
3. Morphological acceleration (morfac)
4. Bed composition and grain sizes
5. Avalanching and slope effects
6. Quasi-3D sediment transport
7. Validation and constraints

Prerequisites¶

• Basic familiarity with XBeach concepts
• Completed the Physics Tutorial
• rompy-xbeach installed (pip install rompy-xbeach)

---

1. Introduction¶

The Sediment component groups all sediment-related parameters:

Sub-component	Purpose
sedtrans	Transport formulations, wave effects, bed slope effects
morphology	Morfac, time windows, avalanching slopes
bed_composition	Grain sizes (D50, D90), density, porosity, layers
numerics	Transport numerical parameters
q3d	Quasi-3D vertical structure
groundwater	Groundwater flow (if gwflow enabled)

Relationship with Physics¶

The Sediment component handles what happens to the bed, while Physics handles hydrodynamics. They work together:

• Physics computes waves and currents
• Sediment uses those to compute transport and bed change
• Bed change feeds back to Physics (updated bathymetry)

---

2. Getting Started¶

Let's start with the simplest case - using XBeach defaults.

In [1]:

from rompy_xbeach.components.sediment import Sediment


def print_params(lines, filename="params.txt"):
    """Special printing to simulate a params.txt file content"""
    max_content_width = max(len(line) for line in lines) if lines else 0
    max_width = max(len(filename), max_content_width)
    box_width = max_width + 2
    print("┌" + "─" * box_width + "┐")
    print("│ " + filename.ljust(max_width) + " │")
    print("├" + "─" * box_width + "┤")
    for line in lines:
        print("│ " + line.ljust(max_width) + " │")
    print("└" + "─" * box_width + "┘")


def show_params(obj, destdir=None):
    """Helper to display parameters that would be written to params.txt."""
    params = obj.get(destdir=destdir)
    content = []
    if not params:
        content.append("")
    else:
        for key, value in params.items():
            content.append(f"{key} = {value}")
    print_params(content)


def print_warning(text):
    """Print text with warning-style highlighting."""
    print(f"\033[48;5;224m\033[30m {text} \033[0m")


# Create Sediment with all defaults
sediment = Sediment()
show_params(sediment)

from rompy_xbeach.components.sediment import Sediment def print_params(lines, filename="params.txt"): """Special printing to simulate a params.txt file content""" max_content_width = max(len(line) for line in lines) if lines else 0 max_width = max(len(filename), max_content_width) box_width = max_width + 2 print("┌" + "─" * box_width + "┐") print("│ " + filename.ljust(max_width) + " │") print("├" + "─" * box_width + "┤") for line in lines: print("│ " + line.ljust(max_width) + " │") print("└" + "─" * box_width + "┘") def show_params(obj, destdir=None): """Helper to display parameters that would be written to params.txt.""" params = obj.get(destdir=destdir) content = [] if not params: content.append("") else: for key, value in params.items(): content.append(f"{key} = {value}") print_params(content) def print_warning(text): """Print text with warning-style highlighting.""" print(f"\033[48;5;224m\033[30m {text} \033[0m") # Create Sediment with all defaults sediment = Sediment() show_params(sediment)

┌────────────┐
│ params.txt │
├────────────┤
│            │
└────────────┘

An empty Sediment() produces no output - XBeach will use its defaults.

XBeach Default Behavior¶

Parameter	Default	Meaning
sedtrans	0 (off)	Sediment transport disabled
morphology	0 (off)	Morphology disabled
form	vanthiel_vanrijn	Transport formulation
morfac	1.0	No morphological acceleration
D50	0.0002 m	Median grain size (fine sand)

Note: Unlike Physics where many processes are on by default, sediment transport and morphology are off by default. You must explicitly enable them.

---

3. Enabling Sediment Transport¶

To enable sediment transport, set sedtrans=True or provide a SedimentTransport object.

3.1 Simple Enable¶

In [2]:

# Enable sediment transport with defaults
sediment_on = Sediment(sedtrans=True)
show_params(sediment_on)

# Enable sediment transport with defaults sediment_on = Sediment(sedtrans=True) show_params(sediment_on)

┌──────────────┐
│ params.txt   │
├──────────────┤
│ sedtrans = 1 │
└──────────────┘

3.2 Transport Formulations¶

XBeach supports several sediment transport formulations:

Formulation	Description	Best For
vanthiel_vanrijn	Van Thiel de Vries & Van Rijn	Dune erosion (default)
soulsby_vanrijn	Soulsby & Van Rijn (1997)	General coastal
vanrijn1993	Van Rijn (1993)	Detailed studies

In [3]:

from rompy_xbeach.components.sediment.transport import SedimentTransport

# Van Thiel de Vries formulation (default, optimized for dune erosion)
sediment_vanthiel = Sediment(
    sedtrans=SedimentTransport(
        form="vanthiel_vanrijn",
    )
)
show_params(sediment_vanthiel)

from rompy_xbeach.components.sediment.transport import SedimentTransport # Van Thiel de Vries formulation (default, optimized for dune erosion) sediment_vanthiel = Sediment( sedtrans=SedimentTransport( form="vanthiel_vanrijn", ) ) show_params(sediment_vanthiel)

┌─────────────────────────┐
│ params.txt              │
├─────────────────────────┤
│ sedtrans = 1            │
│ form = vanthiel_vanrijn │
└─────────────────────────┘

In [4]:

# Soulsby-Van Rijn formulation
sediment_soulsby = Sediment(
    sedtrans=SedimentTransport(
        form="soulsby_vanrijn",
    )
)
show_params(sediment_soulsby)

# Soulsby-Van Rijn formulation sediment_soulsby = Sediment( sedtrans=SedimentTransport( form="soulsby_vanrijn", ) ) show_params(sediment_soulsby)

┌────────────────────────┐
│ params.txt             │
├────────────────────────┤
│ sedtrans = 1           │
│ form = soulsby_vanrijn │
└────────────────────────┘

3.3 Wave Asymmetry and Skewness¶

Wave-induced transport is controlled by facua (or separately facAs and facSk). These parameters control onshore transport due to wave nonlinearity.

In [5]:

# Calibrate wave-induced transport
sediment_waves = Sediment(
    sedtrans=SedimentTransport(
        facua=0.15,  # Combined asymmetry/skewness factor (default: 0.1)
    )
)
show_params(sediment_waves)

# Calibrate wave-induced transport sediment_waves = Sediment( sedtrans=SedimentTransport( facua=0.15, # Combined asymmetry/skewness factor (default: 0.1) ) ) show_params(sediment_waves)

┌──────────────┐
│ params.txt   │
├──────────────┤
│ sedtrans = 1 │
│ facua = 0.15 │
└──────────────┘

In [6]:

# Or set asymmetry and skewness separately
sediment_waves_sep = Sediment(
    sedtrans=SedimentTransport(
        facAs=0.2,   # Asymmetry factor (default: 0.2)
        facSk=0.15,  # Skewness factor (default: 0.15)
    )
)
show_params(sediment_waves_sep)

# Or set asymmetry and skewness separately sediment_waves_sep = Sediment( sedtrans=SedimentTransport( facAs=0.2, # Asymmetry factor (default: 0.2) facSk=0.15, # Skewness factor (default: 0.15) ) ) show_params(sediment_waves_sep)

┌──────────────┐
│ params.txt   │
├──────────────┤
│ sedtrans = 1 │
│ facAs = 0.2  │
│ facSk = 0.15 │
└──────────────┘

3.4 Bed Slope Effects¶

Bed slope affects both the magnitude and direction of transport:

In [7]:

sediment_slope = Sediment(
    sedtrans=SedimentTransport(
        bdslpeffmag="roelvink_total",  # Magnitude modification (default)
        bdslpeffdir="talmon",          # Direction modification
        facsl=1.6,                     # Slope effect factor
        reposeangle=30.0,              # Angle of repose (degrees)
    )
)
show_params(sediment_slope)

sediment_slope = Sediment( sedtrans=SedimentTransport( bdslpeffmag="roelvink_total", # Magnitude modification (default) bdslpeffdir="talmon", # Direction modification facsl=1.6, # Slope effect factor reposeangle=30.0, # Angle of repose (degrees) ) ) show_params(sediment_slope)

┌──────────────────────────────┐
│ params.txt                   │
├──────────────────────────────┤
│ sedtrans = 1                 │
│ bdslpeffdir = talmon         │
│ bdslpeffmag = roelvink_total │
│ facsl = 1.6                  │
│ reposeangle = 30.0           │
└──────────────────────────────┘

3.5 Stirring Mechanisms¶

Control what processes stir up sediment:

In [8]:

sediment_stirring = Sediment(
    sedtrans=SedimentTransport(
        sws=True,                  # Short wave stirring (default: on)
        lws=True,                  # Long wave stirring (default: on)
        turb="wave_averaged",      # Turbulence model (default)
    )
)
show_params(sediment_stirring)

sediment_stirring = Sediment( sedtrans=SedimentTransport( sws=True, # Short wave stirring (default: on) lws=True, # Long wave stirring (default: on) turb="wave_averaged", # Turbulence model (default) ) ) show_params(sediment_stirring)

┌──────────────────────┐
│ params.txt           │
├──────────────────────┤
│ sedtrans = 1         │
│ lws = 1              │
│ sws = 1              │
│ turb = wave_averaged │
└──────────────────────┘

---

4. Morphological Evolution¶

Morphology controls how the bed evolves over time.

4.1 Enabling Morphology¶

In [9]:

from rompy_xbeach.components.sediment.morphology import Morphology

# Enable morphology with defaults
sediment_morph = Sediment(
    morphology=True
)
show_params(sediment_morph)

from rompy_xbeach.components.sediment.morphology import Morphology # Enable morphology with defaults sediment_morph = Sediment( morphology=True ) show_params(sediment_morph)

┌────────────────┐
│ params.txt     │
├────────────────┤
│ morphology = 1 │
└────────────────┘

4.2 Morphological Acceleration (morfac)¶

The morfac parameter accelerates morphological change relative to hydrodynamics. This allows simulating slow processes (hours/days) with shorter hydrodynamic runs.

Example: morfac=10 means 1 hour of waves produces 10 hours of bed change.

In [10]:

sediment_morfac = Sediment(
    morphology=Morphology(
        morfac=10.0,      # 10x acceleration
        morstart=0.0,     # Start morphology at t=0
        morstop=36000.0,  # Stop at t=36000s (10 hours morphological time)
    )
)
show_params(sediment_morfac)

sediment_morfac = Sediment( morphology=Morphology( morfac=10.0, # 10x acceleration morstart=0.0, # Start morphology at t=0 morstop=36000.0, # Stop at t=36000s (10 hours morphological time) ) ) show_params(sediment_morfac)

┌───────────────────┐
│ params.txt        │
├───────────────────┤
│ morphology = 1    │
│ morfac = 10.0     │
│ morstart = 0.0    │
│ morstop = 36000.0 │
└───────────────────┘

4.3 Avalanching¶

Avalanching occurs when slopes exceed critical values. Different slopes apply above and below water:

In [11]:

sediment_aval = Sediment(
    morphology=Morphology(
        dryslp=1.0,    # Critical slope above water (default: 1.0, ~45°)
        wetslp=0.3,    # Critical slope below water (default: 0.3, ~17°)
        hswitch=0.1,   # Depth to switch between dry/wet slopes (m)
        dzmax=0.05,    # Max bed change per timestep (m/s/m)
    )
)
show_params(sediment_aval)

sediment_aval = Sediment( morphology=Morphology( dryslp=1.0, # Critical slope above water (default: 1.0, ~45°) wetslp=0.3, # Critical slope below water (default: 0.3, ~17°) hswitch=0.1, # Depth to switch between dry/wet slopes (m) dzmax=0.05, # Max bed change per timestep (m/s/m) ) ) show_params(sediment_aval)

┌────────────────┐
│ params.txt     │
├────────────────┤
│ morphology = 1 │
│ dryslp = 1.0   │
│ dzmax = 0.05   │
│ hswitch = 0.1  │
│ wetslp = 0.3   │
└────────────────┘

4.4 Non-Erodible Structures¶

Define hard structures that limit erosion:

In [12]:

sediment_struct = Sediment(
    morphology=Morphology(
        struct=True,  # Enable non-erodible layer
        # ne_layer would point to a file defining layer thickness
    )
)
show_params(sediment_struct)

sediment_struct = Sediment( morphology=Morphology( struct=True, # Enable non-erodible layer # ne_layer would point to a file defining layer thickness ) ) show_params(sediment_struct)

┌────────────────┐
│ params.txt     │
├────────────────┤
│ morphology = 1 │
│ struct = 1     │
└────────────────┘

---

5. Bed Composition¶

Bed composition defines sediment properties - critical for transport calculations.

5.1 Grain Sizes¶

The most important parameters are D50 (median) and D90 (90th percentile):

In [13]:

from rompy_xbeach.components.sediment.composition import BedComposition

# Fine sand (typical beach)
sediment_sand = Sediment(
    bed_composition=BedComposition(
        D50=0.0002,   # 0.2 mm median grain size
        D90=0.0003,   # 0.3 mm 90th percentile
    )
)
show_params(sediment_sand)

from rompy_xbeach.components.sediment.composition import BedComposition # Fine sand (typical beach) sediment_sand = Sediment( bed_composition=BedComposition( D50=0.0002, # 0.2 mm median grain size D90=0.0003, # 0.3 mm 90th percentile ) ) show_params(sediment_sand)

┌──────────────┐
│ params.txt   │
├──────────────┤
│ D50 = 0.0002 │
│ D90 = 0.0003 │
└──────────────┘

In [14]:

# Coarse sand / gravel (XBeach-G applications)
sediment_gravel = Sediment(
    bed_composition=BedComposition(
        D50=0.01,    # 10 mm median grain size
        D90=0.015,   # 15 mm 90th percentile
    )
)
show_params(sediment_gravel)

# Coarse sand / gravel (XBeach-G applications) sediment_gravel = Sediment( bed_composition=BedComposition( D50=0.01, # 10 mm median grain size D90=0.015, # 15 mm 90th percentile ) ) show_params(sediment_gravel)

┌─────────────┐
│ params.txt  │
├─────────────┤
│ D50 = 0.01  │
│ D90 = 0.015 │
└─────────────┘

5.2 Sediment Properties¶

In [15]:

sediment_props = Sediment(
    bed_composition=BedComposition(
        D50=0.0002,
        D90=0.0003,
        rhos=2650.0,   # Sediment density (kg/m³, quartz default)
        por=0.4,       # Porosity (void fraction)
    )
)
show_params(sediment_props)

sediment_props = Sediment( bed_composition=BedComposition( D50=0.0002, D90=0.0003, rhos=2650.0, # Sediment density (kg/m³, quartz default) por=0.4, # Porosity (void fraction) ) ) show_params(sediment_props)

┌───────────────┐
│ params.txt    │
├───────────────┤
│ D50 = 0.0002  │
│ D90 = 0.0003  │
│ rhos = 2650.0 │
│ por = 0.4     │
└───────────────┘

5.3 Bed Layering¶

XBeach divides the bed into layers for tracking sediment:

In [16]:

sediment_layers = Sediment(
    bed_composition=BedComposition(
        D50=[0.0002],
        D90=[0.0003],
        nd=3,          # Number of layers (default: 3)
        dzg1=0.1,      # Top layer thickness (m)
        dzg2=0.1,      # Middle layer thickness (m)
        dzg3=0.1,      # Bottom layer thickness (m)
    )
)
show_params(sediment_layers)

sediment_layers = Sediment( bed_composition=BedComposition( D50=[0.0002], D90=[0.0003], nd=3, # Number of layers (default: 3) dzg1=0.1, # Top layer thickness (m) dzg2=0.1, # Middle layer thickness (m) dzg3=0.1, # Bottom layer thickness (m) ) ) show_params(sediment_layers)

┌──────────────┐
│ params.txt   │
├──────────────┤
│ nd = 3       │
│ D50 = 0.0002 │
│ D90 = 0.0003 │
│ dzg1 = 0.1   │
│ dzg2 = 0.1   │
│ dzg3 = 0.1   │
└──────────────┘

5.4 Multiple Sediment Classes¶

For graded sediments, use multiple grain size classes:

In [17]:

sediment_graded = Sediment(
    bed_composition=BedComposition(
        ngd=2,                      # 2 sediment classes
        D50=[0.0001, 0.0004],       # Fine and coarse fractions
        D90=[0.00015, 0.0006],      # Corresponding D90 values
    )
)
show_params(sediment_graded)

sediment_graded = Sediment( bed_composition=BedComposition( ngd=2, # 2 sediment classes D50=[0.0001, 0.0004], # Fine and coarse fractions D90=[0.00015, 0.0006], # Corresponding D90 values ) ) show_params(sediment_graded)

┌──────────────────────┐
│ params.txt           │
├──────────────────────┤
│ ngd = 2              │
│ D50 = 0.0001 0.0004  │
│ D90 = 0.00015 0.0006 │
└──────────────────────┘

---

6. Transport Numerics¶

Numerical parameters control solver behavior:

In [18]:

from rompy_xbeach.components.sediment.transport import TransportNumerics

sediment_numerics = Sediment(
    numerics=TransportNumerics(
        cmax=0.1,        # Maximum concentration (default: 0.1)
        thetanum=1.0,    # Upwind (1.0) vs central (0.5) scheme
    )
)
show_params(sediment_numerics)

from rompy_xbeach.components.sediment.transport import TransportNumerics sediment_numerics = Sediment( numerics=TransportNumerics( cmax=0.1, # Maximum concentration (default: 0.1) thetanum=1.0, # Upwind (1.0) vs central (0.5) scheme ) ) show_params(sediment_numerics)

┌────────────────┐
│ params.txt     │
├────────────────┤
│ cmax = 0.1     │
│ thetanum = 1.0 │
└────────────────┘

---

7. Quasi-3D Transport¶

For situations with strong vertical gradients, enable quasi-3D mode:

In [19]:

from rompy_xbeach.components.sediment.transport import Quasi3D

sediment_q3d = Sediment(
    q3d=Quasi3D(
        kmax=100,      # Number of vertical layers (default: 100)
        sigfac=1.3,    # Layer distribution factor
    )
)
show_params(sediment_q3d)

from rompy_xbeach.components.sediment.transport import Quasi3D sediment_q3d = Sediment( q3d=Quasi3D( kmax=100, # Number of vertical layers (default: 100) sigfac=1.3, # Layer distribution factor ) ) show_params(sediment_q3d)

┌──────────────┐
│ params.txt   │
├──────────────┤
│ q3d = 1      │
│ kmax = 100   │
│ sigfac = 1.3 │
└──────────────┘

---

8. Validation and Constraints¶

rompy-xbeach validates your configuration and catches common errors.

8.1 Grain Size Validation¶

D90 must be greater than D50:

In [20]:

from pydantic import ValidationError

try:
    invalid_grains = BedComposition(
        D50=[0.0003],  # D50 larger than D90!
        D90=[0.0002],
    )
except ValidationError as e:
    print_warning(f"{e.errors()[0]['msg']}")
    print("\n(Validation error caught)\n")

from pydantic import ValidationError try: invalid_grains = BedComposition( D50=[0.0003], # D50 larger than D90! D90=[0.0002], ) except ValidationError as e: print_warning(f"{e.errors()[0]['msg']}") print("\n(Validation error caught)\n")

 Value error, D90[0] (0.0002) must be greater than D50[0] (0.0003) 

(Validation error caught)

8.2 Sediment Class Consistency¶

When using multiple classes, all lists must have the same length:

In [21]:

try:
    invalid_classes = BedComposition(
        ngd=2,
        D50=[0.0002],  # Only 1 value, but ngd=2!
        D90=[0.0003],
    )
except ValidationError as e:
    print_warning(f"{e.errors()[0]['msg']}")
    print("\n(Validation error caught)\n")

try: invalid_classes = BedComposition( ngd=2, D50=[0.0002], # Only 1 value, but ngd=2! D90=[0.0003], ) except ValidationError as e: print_warning(f"{e.errors()[0]['msg']}") print("\n(Validation error caught)\n")

 Value error, D50 must have 2 values (one per sediment class), but got 1 values. Set ngd=1 or adjust D50. 

(Validation error caught)

8.3 Cross-Parameter Warnings¶

Some parameter combinations generate warnings:

In [22]:

import logging
logging.basicConfig(level=logging.WARNING)

# Bore-averaged turbulence with ruessink_vanrijn waveform
sediment_warning = Sediment(
    sedtrans=SedimentTransport(
        turb="bore_averaged",
        waveform="ruessink_vanrijn",  # Incompatible combination
    )
)
print("\n(A warning was logged above)")

import logging logging.basicConfig(level=logging.WARNING) # Bore-averaged turbulence with ruessink_vanrijn waveform sediment_warning = Sediment( sedtrans=SedimentTransport( turb="bore_averaged", waveform="ruessink_vanrijn", # Incompatible combination ) ) print("\n(A warning was logged above)")

2026-01-10 16:51:36 [WARNING] rompy_xbeach.components.sediment.transport: ! Bore-averaged turbulence (turb='bore_averaged') cannot be combined with the Ruessink et al. (2012) wave form (waveform='ruessink_vanrijn'). The Ruessink formulation does not determine an exact wave shape, which is required to calculate the bore interval for bore-averaged turbulence. Consider using waveform='vanthiel' or turb='wave_averaged' instead.
2026-01-10 16:51:36 [WARNING] rompy_xbeach.components.sediment.transport: ! Bore-averaged turbulence (turb='bore_averaged') cannot be combined with the Ruessink et al. (2012) wave form (waveform='ruessink_vanrijn'). The Ruessink formulation does not determine an exact wave shape, which is required to calculate the bore interval for bore-averaged turbulence. Consider using waveform='vanthiel' or turb='wave_averaged' instead.

(A warning was logged above)

---

9. Putting It All Together¶

Here's a comprehensive example for a storm impact simulation:

In [23]:

# Storm impact simulation with morphology
sediment_storm = Sediment(
    # Sediment transport
    sedtrans=SedimentTransport(
        form="vanthiel_vanrijn",
        facua=0.15,
        bdslpeffmag="roelvink_total",
        sws=True,
        lws=True,
        turb="wave_averaged",
    ),
    
    # Morphology with acceleration
    morphology=Morphology(
        morfac=10.0,
        morstart=0.0,
        morstop=36000.0,
        dryslp=1.0,
        wetslp=0.3,
    ),
    
    # Bed composition (fine sand)
    bed_composition=BedComposition(
        D50=[0.0002],
        D90=[0.0003],
        rhos=2650.0,
        por=0.4,
    ),
    
    # Numerics
    numerics=TransportNumerics(
        cmax=0.1,
    ),
)

show_params(sediment_storm)

# Storm impact simulation with morphology sediment_storm = Sediment( # Sediment transport sedtrans=SedimentTransport( form="vanthiel_vanrijn", facua=0.15, bdslpeffmag="roelvink_total", sws=True, lws=True, turb="wave_averaged", ), # Morphology with acceleration morphology=Morphology( morfac=10.0, morstart=0.0, morstop=36000.0, dryslp=1.0, wetslp=0.3, ), # Bed composition (fine sand) bed_composition=BedComposition( D50=[0.0002], D90=[0.0003], rhos=2650.0, por=0.4, ), # Numerics numerics=TransportNumerics( cmax=0.1, ), ) show_params(sediment_storm)

┌──────────────────────────────┐
│ params.txt                   │
├──────────────────────────────┤
│ sedtrans = 1                 │
│ bdslpeffmag = roelvink_total │
│ facua = 0.15                 │
│ form = vanthiel_vanrijn      │
│ lws = 1                      │
│ sws = 1                      │
│ turb = wave_averaged         │
│ morphology = 1               │
│ dryslp = 1.0                 │
│ morfac = 10.0                │
│ morstart = 0.0               │
│ morstop = 36000.0            │
│ wetslp = 0.3                 │
│ D50 = 0.0002                 │
│ D90 = 0.0003                 │
│ rhos = 2650.0                │
│ por = 0.4                    │
│ cmax = 0.1                   │
└──────────────────────────────┘

---

10. Integration with Config¶

The Sediment component is used as part of the main Config:

In [24]:

config_example = """
from rompy_xbeach import Config
from rompy_xbeach.components.physics import Physics
from rompy_xbeach.components.sediment import Sediment
from rompy_xbeach.components.sediment.transport import SedimentTransport
from rompy_xbeach.components.sediment.morphology import Morphology
from rompy_xbeach.components.output import Output

config = Config(
    project="storm_erosion",
    grid=grid,
    bathy=bathy,
    
    # Physics (hydrodynamics)
    physics=Physics(
        wavemodel=Surfbeat(),
        flow=True,
    ),
    
    # Sediment (transport and morphology)
    sediment=Sediment(
        sedtrans=SedimentTransport(form="vanthiel_vanrijn"),
        morphology=Morphology(morfac=10.0),
    ),
    
    # Output
    output=Output(
        outputformat="netcdf",
        tintg=3600,
    ),
)

config.generate(destdir="./model_run")
"""

print("Config integration example:")
print(config_example)

config_example = """ from rompy_xbeach import Config from rompy_xbeach.components.physics import Physics from rompy_xbeach.components.sediment import Sediment from rompy_xbeach.components.sediment.transport import SedimentTransport from rompy_xbeach.components.sediment.morphology import Morphology from rompy_xbeach.components.output import Output config = Config( project="storm_erosion", grid=grid, bathy=bathy, # Physics (hydrodynamics) physics=Physics( wavemodel=Surfbeat(), flow=True, ), # Sediment (transport and morphology) sediment=Sediment( sedtrans=SedimentTransport(form="vanthiel_vanrijn"), morphology=Morphology(morfac=10.0), ), # Output output=Output( outputformat="netcdf", tintg=3600, ), ) config.generate(destdir="./model_run") """ print("Config integration example:") print(config_example)

Config integration example:

from rompy_xbeach import Config
from rompy_xbeach.components.physics import Physics
from rompy_xbeach.components.sediment import Sediment
from rompy_xbeach.components.sediment.transport import SedimentTransport
from rompy_xbeach.components.sediment.morphology import Morphology
from rompy_xbeach.components.output import Output

config = Config(
    project="storm_erosion",
    grid=grid,
    bathy=bathy,

    # Physics (hydrodynamics)
    physics=Physics(
        wavemodel=Surfbeat(),
        flow=True,
    ),

    # Sediment (transport and morphology)
    sediment=Sediment(
        sedtrans=SedimentTransport(form="vanthiel_vanrijn"),
        morphology=Morphology(morfac=10.0),
    ),

    # Output
    output=Output(
        outputformat="netcdf",
        tintg=3600,
    ),
)

config.generate(destdir="./model_run")

---

Summary¶

Key Takeaways¶

1. Sediment transport and morphology are OFF by default - you must enable them

2. Transport formulation choice matters:

   • vanthiel_vanrijn: Dune erosion (default)
   • soulsby_vanrijn: General coastal

3. Morfac accelerates morphology - use wisely:

   • morfac=1: Real-time (slow)
   • morfac=10-100: Typical for storm simulations

4. Grain size is critical:

   • Fine sand: D50 ~ 0.0002 m
   • Gravel: D50 ~ 0.01 m

5. Validation catches errors early - trust the error messages

Typical Morfac Values¶

Application	Morfac	Duration
Detailed erosion	1	Hours
Storm events	5-10	Hours to days
Seasonal	20-50	Weeks to months
Long-term	50-200	Months to years

Next Steps¶

• See the Physics Tutorial for hydrodynamics
• See the Output Tutorial for output configuration
• See the Full Example for a complete workflow

Resources¶

• XBeach Manual - Sediment Transport
• XBeach Manual - Morphology
• rompy-xbeach API Reference
• Parameter Reference