The Pride demand model (developed for Victorian farming districts) replicates water requirements for a cropped area using a combination of climate data, crop culture and knowledge of traditional farming practices. These irrigation requirements are used to generate orders within regulated river systems or to drive extractions from unregulated systems. It is governed by factors which determine crop water use - principally the irrigation culture, climate, the characteristics of the soil and the type of irrigation system. In Source, a Pride demand model is configured and managed in the water user node feature editor.
To create a new Pride model, right click on Demand Models and choose Add Pride. Figure 1 shows the parameters that must be configured.
Figure 1. Pride demand model, main screen
Channel Efficiencies
Figure 2. Pride demand mode, Channel Efficiencies
Limit Curve
The limit curve prevents a demand node from using all of its available allocation too early in the season. It is defined based on a user-input relationship between announced or available allocation and limit. The Allocation Proportion can be set up as a constant or it can be customised using a function to vary according to the allocation percent set up in a Resource Assessment. Figure 3 shows an example where a constant has been specified for the Allocation Proportion.
Figure 3. Pride demand model, Limit curve
The limit curve (Cumulative Restricted Demand in the results) will reflect the changes in Percent Per Share Entitlement (as shown on the left and right of Figure 4).
Figure 4. Pride demand model, Limit curve results
Evaporation
Evaporation is one of the climatic factors influencing demand and is specified using a time series. Figure 5 shows an example of the time series allocated to the model.
Figure 5. Pride demand model, Evaporation
Rainfall
The second climatic factor affecting the model is rainfall. You can add rainfall models by right clicking on Rainfall Models and choosing Add Rainfall in the contextual menu. You must also allocate the weighting to assign to each rainfall model (shown in Figure 6), which must add to 1. Figure 7 shows an example of a rainfall model.
Figure 6. Pride demand model, Rainfall
Figure 7. Pride demand model, Rainfall model a
Return Flow
Refer to Return flows for more information. Note that the percentage of volume supplied can be greater than 100%. This indicates that there is more return flow from the irrigator than diversions due to rainfall runoff.
Crop
As shown in Figure 8, you can configure the following crop parameters:
- Crop - This can be specified as an annual pasture or a perennial one.
- Annual pasture - Allows you to setup a crop as annual pasture, which is traditionally irrigated in early spring and then again in Autumn.
- Threshold - irrigation at the beginning of the season is triggered when this threshold is exceeded.
Figure 8. Pride demand model, Crop
Crop Area
This can be specified as a single, constant value, a time series or as a function.
If an annual time series of crop areas is not used, you can specify a single set of crop areas, which applies to the entire model period. Ensure that the order and number of crops are consistent across all steps of model development. The model assumes that the first crop is Annual Pasture. If you do not wish to model Annual Pasture, then you must enter zero hectares of Annual Pasture as the first crop.
Figure 9. Pride demand model, Crop, Area
