# Model help:AquaTellUs

## AquaTellUs

A 2-D process–response model, AQUATELLUS, has been designed that integrates fluvio-deltaic process descriptions for large spatial and temporal scales. Over large (geological) time scales, major floods and storms are the relevant transport events.

## Model introduction

AquaTellUs models fluvial-dominated delta sedimentation. AquaTellUS uses a nested model approach; a 2D longitudinal profiles, embedded as a dynamical flowpath in a 3D grid-based space. A main channel belt is modeled as a 2D longitudinal profile that responds dynamically to changes in discharge, sediment load and sea level. Sediment flux is described by separate erosion and sedimentation components. Multiple grain-size classes are independently tracked. Erosion flux depends on discharge and slope, similar to process descriptions used in hill-slope models and is independent of grain-size. Offshore, where we assume unconfined flow, the erosion capacity decreases with increasing water depth. The erosion flux is a proxy for gravity flows in submarine channels close to the coast and for down-slope diffusion over the entire slope due to waves, tides and creep. Erosion is restricted to the main flowpath. This appears to be valid for the river-channel belt, but underestimates the spatial extent and variability of marine erosion processes.

Deposition flux depends on the stream velocity and on a travel-distance factor, which depends on grain size (i.e. settling velocity). The travel-distance factor is different in the fluvial and marine domains, which results in a sharp increase of the settling rate at the river mouth, mimicking bedload dumping.

Dynamic boundary conditions such as climatic changes over time are incorporated by increasing or decreasing discharge and sediment load for each time step.

## Model parameters

Parameter Description Unit
First parameter Description parameter [Units]
Parameter Description Unit
First parameter Description parameter [Units]

## 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

• Lower boundary condition for sediment flux
 $\displaystyle{ {\frac{\partial H_{x}}{\partial t_{x}}} = {\frac{\partial F}{\partial x}} + T }$ (1)
 $\displaystyle{ {\frac{\partial F_{x}}{\partial x}} = {\frac{\partial F_{ero \left ( x \right )}}{\partial x}} - {\frac{\partial F_{sed \left ( x \right )}}{\partial x}} }$ (2)
 $\displaystyle{ {\frac{\partial F_{ero}}{\partial x}} = k S^m Q \left ( x \right ) }$ (3)
 $\displaystyle{ F = F_{in} + F_{ero} = F_{sed} + F_{out} }$ (4)
 $\displaystyle{ {\frac{\partial F_{sed}}{\partial x}} = {\frac{F_{\left ( x,t \right )}}{h}} }$ (5)
 $\displaystyle{ F_{sed \left ( x,t \right )} = F_{sed \left ( x-1,t \right )} - \left ( F_{sed \left (x-1,t \right )} 2 D_{coast} tan \alpha \right ) }$ (6)

## Notes

Any notes, comments, you want to share with the user

Numerical scheme

## Examples

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

## Developer(s)

Name of the module developer(s)

Key papers

## Links

Any link, eg. to the model questionnaire, etc.