Model:SimClast

SimClast

SimClast Questionnaire

Contact Information

Model:	SimClast
Contact person:	Rory Dalman
Institute:	Delft University of Technology
City:	Delft
Country:	The Netherlands
Email:	r.a.f.dalman@tudelft.nl
2nd person involved:	--
3rd person involved:	--

Model description

Model type:

Modular model for the terrestrial, coastal and marine domain.

Description:

SimClast is a basin-scale 3D stratigraphic model, which allows several interacting sedimentary environments. Processes included are; fluvial channel dynamics and overbank deposition, river plume deposition, open marine currents, wave resuspension, nearshore wave induced longshore and crosshore transport. This combined modelling approach allows insight into the processes influencing the flux of energy and clastic material and the effect of external perturbations in all environments. Many governing processes work on relatively small scales, e.g. in fluvial settings an avulsion is a relatively localised phenomenon. Yet, they have a profound effect on fluvial architecture. This means that the model must mimic these processes, but at the same time maintain computational efficiency. Additionally, long-term models use relatively large grid-sizing (km scale), as the area to be modelled is on the scale of continental margins. We solve this problem by implementing! the governing processes as sub-grid scale routines into the large-scale basin-filling model. This parameterization greatly refines morphodynamic behaviour and the resulting stratigraphy. This modelling effort recreates realistic geomorphological and stratigraphic delta behaviour in river and wave-dominated settings.

Technical information

Supported platforms:	Windows
Programming language:	Fortran77, Fortran90
Model was developed started from:	1998 and development still takes place
To what degree will the model become available:	As code, teaching tool and executable
Current license type:	GPL v2
Memory requirements:	1GB
Typical run time:	5 minutes up to 24 hours

Input / Output description

Input parameters:	Sealevel curve subsidence rainfall (variable through time) multiple rivers with variable discharge and sediment load through time initial topography wind velocity and direction/or wave height and propagation direction marine current velocity and location sediment transport parameters number of grainsizes, grainsize dimensions and density fluvial channel dimensions
Input format:	ASCII
Output parameters:	3D stratigraphy (age, provenance, grainsize, peat fraction) Morphodynamic maps of grainsize, discharge, sediment erosion and deposition
Output format:	ASCII
Post-processing software (if needed):	no
Visualization software (if needed):	yes, Matlab and Surfer

Process description

Processes represented by model:	Fluvial/alluvial processes; Aggrading fluvial channels in one gridcell with crevasse. Subgrid sedimentation mimics alluvial ridge aggradation and overbank deposition. Avulsions are modelled one dimensionally by calculating the flow and sediment transport at prospective avulsion nodes. See also Dalman & Weltje (2008). Floodplain processes; Differential compaction, groundwater table, peat growth and overbank deposition Hypopycnal plume and marine currents: Rivers deliver sediment and water to the sea, where the river momentum spreads the suspended sediment in a plume. Multiple plumes and longshore current hydrodynamics are calculated using a potential flow routine. Subsequent sedimentation due to fallout uses the removal rate principle after Syvitski et al (1988). Wave resuspension and crosshore transport; Waves are modelled using linear Airy and Stokes wave theory. Deepwater wave height is derived from a Gaussian distribution to represent natural storm variability The asymmetric waves preferentially transport the sands (bedload fraction) shorewards and the fines (suspended load fraction) offshore. In combination with a littoral drift routine this allows waves to rework and transport sediments.
Key physical parameters & equations:	tba
Length scale & resolution constraints:	SimClast can theoretically be used on a length scale upwards of 20 kms, the upper limit is dependant on memory and processing restrictions. Typical length scales vary from 25 to 500 km. The highest resolution is mainly dependant on the use of intracellular fluvial deposition, as described in Dalman & Weltje (2008) this restricts the minimum cell size to 4 kms. Recent addition of floodplain process reduces this to 500 m.
Time scale & resolution constraints:	Total time scale is merely dependant on computing time, typically on the order of several thousands to 100,000 years. Time steps are restricted to 1 year.
Numerical limitations and issues :	tba

Testing

Available calibration data sets:	tba (see current work in progress)
Available test data sets:	For now only a basic synthetic surface.
Ideal data for testing:	ClastSim is ideally used for field tests, a preferably well-studied area with some knowledge of the sediment budget is preferred. Most continental to shallow marine clastic coastal systems without too much tidal influence can be used.

User groups

Currently or plans for collaborating with:

Current work in progress, will be updated when ready; Holocene development of the Rhine-Meuse delta (Utrecht University). Late Quaternary morphology and stratigraphy of the Northern Adriatic Basin. Large-scale stratigraphic patterns on the Vietnam shelf since the LGM (University of Kiel).

Documentation

Key papers of the model:	Dalman, R.A.F., & Weltje, G.J., 2008. Sub-grid parameterisation of fluvio-deltaic processes and architecture in a basin-scale stratigraphic model. Computers & Geosciences, Computers & Geosciences; Predictive Modeling in Sediment Transport and Stratigraphy. Volume 34, Issue 10, October 2008, Pages 1370-1380
Is there a manual available:	no
Model website if any:	--

Additional comments

Comments:

--