Plugin was written by Andrew Freebairn, it is based on Scott Wilkinson's et al paper "Development of a time-stepping sediment budget model for assessing land use impacts in large river basins". It also borrows from the Dynamic SedNet plugin developed at DERM by Robin Ellis and Ross Searle (now at CSIRO).
|License||As-is, use at your own risk|
The plugin is a collection of sediment and nutrient models and their associated management tools (e.g. parameterisers).
|Data pre-processing||Derivations from DEM||TIME spatial analysis model (outputs for parameterisation)*|
Hill-slope* (fine sediment)
Gully* (fine sediment)
Bank* (fine sediment)
Nutrient (Dissolved, Particulate)
Sediment (flood plain deposition)*
|Sediment (deposition)* (simple mass transformation factor)|
|Sediment (in-stream fine deposition)|
|Sediment (in-stream coarse deposition)|
Nutrient (deposition, decay)
Nutrient (deposition, decay)
Land-use area definition*
Main UI additions*
Access to plug-in functions*
Mapping data into a database or saving to a file*
Spatial contributions of sediment
Unit testing of each component*
Regression testing of components and the system*
* Work completed and\or released
Using the plugin
Load using the Plugin manager. Constituent generation models will appear in the Constituent Model Configuration control, Edit–>Constituent Models... Temporal parameterisation is found under the "Tools" menu, "dSedNet Gully Model Parameteriser" and "dSedNet Hillslope Model Parameteriser". The "Spatial Parameteriser" is part of the Plugin it can be found in the "Edit" menu, Edit–>Spatial Parameteriser...
The following is a list of steps to set up a Source scenario to use dSedNet models.
- Load the “dSedNet” plug-in using the 'Plugin Manager'
- Use the dSednetDerivedLayers to derive useful data. This tool removes the need to have a DEM saved within the project file. It also generates many of the spatial parameter layers used to parameterise the dSednet models and to construct the base scenario. Inputs required are, a hydrologically sound DEM, stream threshold (50km^2 is default), the easting and northing of the outlet cell (if one is not given all outlets will be produced at the edge of the data provided) and the file path to save results.
- Define a Source Catchments scenario using the “Geographic Wizard”. When defining the 'Network' use the option to 'Draw Network' and use the layers generated from the above process.
- Define FU areas with the use of a land-use map (raster) which covers 100% of the catchment (This is a prerequisite for using the Spatial Parameteriser)
- Select a rainfall runoff model and assign parameters/calibrate it
- Define constituents (e.g. “Fine” and “Coarse”).
- You may need to define multiple sources of constituents for a given functional unit (e.g. Hill slope and Gully)
- Assign models for constituent generation - (“Hillslope Model – dSedNet” and “Gully Model - dSedNet”) and enter static model parameters
- Assign spatial parameters to selected constituent generation models using the Spatial Parameterisation tool.
- Execute the temporal parameterisers for associated constituent generation models
Defining FU areas
Fu areas need to be define with a spatial layer (land use) Edit → Functional Units → Assign Area Via Raster...
The land use layer has the same number of land use codes and they are all mapped to a corresponding FU in the scenario, ie there is a corresponding values for each catchment cell
If the land use layer changes the scenario will be made redundant. (Tip - copy the scenario once you initial define it )
Select the check box to 'Save spatial FU data'
Hill slope erosion component model
“The fine sediment supplied from hillslopes in each FU to the stream network is the product of gross erosion rate, FU area and a hillslope sediment delivery ratio HSDR. Hillslope supply from each subcatchment is then the sum of the contributions from all FUs in the sub‐ catchment” (Wilkinson et al. 2014). Gross daily hillslope erosion in each FU is estimated using the Modified Universal Soil Loss Equation (MUSLE) (parameters R*K*L*S*C*P), FU area is provided by Source, and HSDR is a ratio [0…1] set by the expert user.
|USLE HSDR - Fine||Hill sediment delivery ratio||Default 0.1 (Prosser et al, 2001)|
|R||rainfall erosivity factor||Internally calculated based on rainfall for the given timestep and uses Yang and Yu (1987) method|
|KLSC||Soil erodibility factor, slope length, steepness factor and cover factor (static)|
K - Soil erodability (Wischmeier and Smith (1978))
L - Slope length (default, 1)
S - Steepness raster generated by dSednetDerivedLayers for steepness factor
C - Cover factor (Rosewell, 1993)
|KLSCdynamic||Soil erodibility factor, slope length, steepness factor and cover factor||Where C is played as a time series to capture the temporal variance of vegetation cover. Perform raster operations, where static KLS are multiplied together to for a single KLS raster. Then for each daily C layer multiple with the KLS raster to produce a daily layers for KLSC. Use the spatial parameteriser the model, using t|
|S||mean summer rainfall||Internally calculated by the temporal parameterisation|
|P||mean annual rainfall||Internally calculated by the temporal parameterisation|
|R Factor Rainfall Threshold||R rainfall threshold||12.7 mm (If daily rainfall is less than this threshold then the R value is set to 0)|
|Alpha||Rainfall erosivity factor used to calculate R||Calculated at runtime based upon S and P|
|Beta||Rainfall erosivity factor used to calculate R||Default values are set - 1.49, or use the Beta raster generated by dSednetDerivedLayers which uses Yang and Yu (1987) method|
|Eta||rainfall erosivity factor used to calculate R||Default, 0.389 (Yang and Yu, 1987) method|
|DWC||Dry Weather Concentration||User defined from literature|
|Off set from day of year||Number of days that are subtracted from the current day of year||Default, 15|
|Daily Rain||Rainfall that fell on a single 24hrs measured in mm||This will be assigned at runtime by the system. It is obtained from the rainfall runoff model for the associated FU|
R is based on Yang et al (2015) - Yang Xihua, Yu Bofu (2015) Modelling and mapping rainfall erosivity in New South Wales, Australia. Soil Research 53, 178-189.
Beta base on on Yang et al (2015) - Yang Xihua, Yu Bofu (2015) Modelling and mapping rainfall erosivity in New South Wales, Australia. Soil Research 53, 178-189.
The parameter KLSC (static) (or KLSCdynamic, dynamic) can be provided to the model in a number of different ways.
- As a played timeseries (KLSCdynamic), generated by the spatial parameteriser from a series of spatial layers
- As a constant in full (KLSC)
- In parts where KLSC is static and C is dynamic (KLS static and C played as a input). Note here KLSC is only made up of that components K, L and S, the C component is the variable
If you have previously applied a value to KLSC (or C) as a constant and are changing to use play a timeseries to KLSCdynamic (option 1 above) you will need to set the static value back to 0 (zero)
Gully erosion component model
“Gully erosion represents ongoing incision and enlargement of hillslope drainage lines and streams which have smaller contributing areas than the upstream extent of the model stream network. It also represents erosion of ‘badland’ areas of deep soil or alluvium (e.g. Brooks et al. 2009). Such erosion processes are usually caused by land use intensification” (Wilkinson et al. 2014). An input map of the current areal density of gullies, their age and cross‐section, together with relevant soil properties are used to calculate volume.
|Gully SDR - Fine||Sediment delivery ration||Default to 0.3|
|Gully SDR - Coarse||Sediment delivery ration||Default to 0.7|
|Gully Density||km/km2 within function unit||Spatial analysis of project catchment, mapping gullies against most recent aerial imagery layers|
|Year of Disturbance||Year as integer||Catchment local knowledge|
|Year of Gully Density||Year as integer||Catchment local knowledge|
|End Year of Gully||Year as integer||Catchment local knowledge|
|Total Gully Volume||m3||Internally calculated by the temporal parameterisation|
|Gully Soil Bulk Density||Average bulk density of gully material (grams per cubic centimetre)||Input layer - spatial parameterisation|
|Gully Clay + Silt Percentage||%||Input layer - spatial parameterisation|
|Gully Cross Section Area||m2||Default - 10 m2|
|Average Gully Activity Factor||Management factor (1 - 3). Used to override sediment supply from the long term rate to account for changes in erosion rates||Catchment local knowledge|
|Gully Annual Average Sediment Supply||Internally calculated||Internally calculated by the temporal parameterisation|
|Gully Daily Runoff Power Factor||Default to 1.4||User defined from literature|
|Gully Long Term Runoff Factor||Internally calculated||Internally calculated by the temporal parameterisation|
|Gully Management Practice Factor||(0 - 2), Describing the proportional change in sediment yield from historical rates (usually reduction) associated with better management practice||Catchment local knowledge|
Streambank sediment supply component model
Streambank erosion is modelled along the model stream network, while channel erosion upstream of the network is represented by gully erosion. Thus, the threshold catchment area used to define the upper limit of the stream network should include all streams having significant streambank erosion that are not represented in the gully density grid. The suspended sediment supply from streambank erosion along a link (t/day) is derived by multiplying the mean-annual SedNet function of stream power and bank erodibility (Wilkinson et al.,2009).
|Link Slope||Average channel slope (m/m)||use the Reach slope raster generated by dSednetDerivedLayers)|
|Link Length||Length of main channel (m)||use the Reach length raster generated by dSednetDerivedLayers)|
|Link Width||Width of main channel (m)y||Currently not used|
|Link Depth||Channel Depth||Currently not used|
|Bank Height||Bank Height||Observations|
|Channel Roughness||Channel roughness||Mannings N value|
|Riparian Vegetation Percentage||Riparian Vegetation Percentage||Observations|
|Bank Full Flow||The flow when the stream is full to the top of the bank||Internally calculated by the temporal parameterisation|
|Bank Full Flow Annual Recurrence Interval||Annual Recurrence Interval of the flow when the stream is full to the top of the bank||User defined from literature|
|Max Riparian Vegetation Effectiveness||Riparian Vegetation Percentage - Effectiveness||User defined from literature|
|Soil Erodibility||Soil Erodibility %||Input layer - spatial parameterisation|
|Erosion Coefficient||Adjusted for long-term rates of bank retreat as observed (0.00001)||Observations|
|Soil Percent Fine Particles||Soil Percent Fine Particles %||Input layer - spatial parameterisation|
|Sediment Bulk Density||The weight (tonnes) of 1m3 of sediment||Input layer - spatial parameterisation|
|Long Term Average Daily Flow||Long Term Average Daily Flow raised to the Daily Flow Power Factor||Internally calculated by the temporal parameterisation|
|Daily Flow Power Factor||Used to manually fit data of bank erosion rates||Default to 1.4|
Floodplain deposition component model
The mass of fine sediment deposited on floodplains adjacent to a link is estimated as a proportion of the incoming load, based on the proportion of discharge flooding overbank and the likelihood of settling on the floodplain considering particle size and floodplain residence time (Prosser et al., 2001b)
|Bank Full Flow||The flow when the stream is full to the top of the bank (m3/s)||Part of parameterisation|
|Sediment Settling Velocity||Sediment Settling Velocity m/s (floodplain)||User defined - Default 0.0007 (min - 0.0001, max - 0.5)|
|Flood Plain Area||m2||Spatial data|
Reach component model
This component is a combination of the streambank component and the floodplain component as there can only be on constituent generation model assigned to a link.
Mass Transformation model
The mass transformation model is a simple scalar model that multiplies the total daily constituent mass of a link by a factor.
TotalDailyConstsituentMass = InitialStoredMass + UpstreamFlowMass + CatchmentInflowMass + AdditionalInflowMass;
ProcessedLoad = TotalDailyConstsituentMass* Factor;
|Factor||Multiplier that will be applied to the link mass||User defined - Default 1.0|
Gully erosion model parameters that require a value before executing the temporal parameteriser
Gully cross-sectional area
Gully year of disturbance
Gully year density raster
Gully soil bulk density
Hillslope and gully erosion model parameters that are assigned by the temporal parameteriser
Mean summer rainfall
Mean annual rainfall
Total gully volume
Gully annual average sediment supply
Gully long-term runoff factor
Temporal parameterisation has been developed within the dSedNet plug-in. Its function is to parameterise model parameters with values obtained via analysis of a model’s output time-series. For example the long term annual average of runoff from a FU can be used as a parameter value for a model allocated to that particular FU.
The temporal parameterisation for particular models in the dSedNet plug-in has been implemented as a black box. The user only needs to set initial model parameter values and then run the parameteriser. The tool has been configured to record the required time-series while the model executes one full run (Note that changing the time period of the model run will produce different values. This may be a problem if the model is later executed over a different time period, e.g Drought vs Normal season). Finally the desired statistic is calculated and the result applied to the correct model parameter for each FU with that model.
- Temporal parameterisation is the last step of parameterisation
- Make sure the simulation period is define. Altering the period will produce differing results
- The hydrological model has be calibrated
Can be used to parameterise FU, Catchment and Link models, either single parameters or played time series (similar to the climate input tool)
- FU areas must be defined with a raster and the raster values must have the same number of categories as there are FUs
- If using the spatial parameteriser the layers used must be comparable with the landuse layer used to define the FU areas. Same geometry (cell sizes, number of rows and columns, lower left corner coordinates)
- If FU areas change the any previous parameteriation of models will be deemed incorrect and will need to be defined again
There is at least one layer to process for spatially assigning inputs
Layers are labeled ddMMyyyy
Each layers represent continuous days (no gaps)
Source code available https://bitbucket.org/ewater/sourceplugin.csiro.dsednet
Main Menu elements
FU Model Parameterised static parameter (Hillslope Model - Parameter KLSC)
FU Model Parameterise temporal inputs (Hillslope Model - Parameter C)
On completion the time series data will be found in "Data Sources" under the subheading of "Spatial Data to TS Import"
Link Model Parameterise static parameter (Reach Model - Parameter Link Slope)
Data pre-processing (TIME spatial analysis - dSednetDerivedLayers model)
Which can be found in Tools-->Plugins→SourcePlugin.CSIRO.dSedNet→dSednetDerivedLayers
Data is dragged and dropped onto the spatial component of the widget.
Note: The Beta factor is calculated from latitude, ensure that your DEM projection is 'MGA'
- DEM raster (The geometry of this raster should be replicated for all others used, e.g. Landuse raster)
- Stream threshold (Contributing area above a stream cell)
- Easting and Northing of outlet and
- Directory path to save outputs
- Stream raster
- Reach slope raster (used to parameterise Gully or Reach model), at the subcatchment scale
- Reach length raster (used to parameterise Gully or Reach model), at the subcatchment scale
- Sub catchment raster (used to define the scenario)
- Network shape file (used to define the scenario)
- Slope raster
- Steepness factor raster (used to parameterise Hill slope model)
- Beta factor raster (used to parameterise Hill slope model)