Creating and Editing the Model

The model can consist of up to six layers:

• three node layers: junctions, reservoirs and tanks

• three link layers: pipes, valve, and pumps

Each of the six objects is reperesented in QGIS by it’s own layer. Layers do not need to be created if they are not used for the model. There is a convenience function to create these empty layers with appropriate fields and some default styling, but any layer with the appropriate geometry type (points for nodes and linestrings for links) and with the minimum necessary fields can be used.

Creating Layers

You can use the ‘new’ button on the toolbar to create a set of layers with default properites.

Alternatively, for more control, you can use the ‘Create Template Layers’ processing tool.

You can also use any existing layers.

Attributes

Attributes are based on the attributes within WNTR, with some adaptations:

• All layers can optionally use the attribute ‘name’ to give a name to each item, which will be visible on the output layer. This must be a string. If no name is given, it will be automatically generated.

• All patterns and curves are input to each element, rather than as a reference to a pattern within WNTR.

• All geographical (coordinates, vertices) and netowrk-related (start_node_name and end_node_name) attributes are calculated automatically based on the geomtry of the features.

All attributes are optional, except those marked Required

Table 2 Possible Junction Layer Attributes

Attribute	If not set
base_demand	Required
elevation	0
demand_pattern	No pattern - constant demand
emitter_coefficient	None
initial_quality	0

Table 3 Possible Reservoir Layer Attributes

Attribute	If not set
base_head	0
head_pattern	No pattern - constant head
initial_quality	0

Table 4 Possible Tank Layer Attributes

Attribute	If not set
elevation	0
init_level	Required
min_level	0
max_level	Required
diameter	Required
min_vol	0
vol_curve	No curve- cylindrical tank
overflow	False
inital_quality	0
mixing_fraction	None
mixing_model	None
bulk_coeff	None

Table 5 Possible Pipe Layer Attributes

Attribute	If not set
diameter	Required
roughness	Required
minor_loss	0
initial_status	Open
check_valve	False
bulk_coeff	None
wall_coeff	None

Table 6 Possible Pump Layer Attributes

Attribute	If not set
pump_type pump_curve power base_speed speed_pattern initial_status Initial_setting	POWER None 1 None Open None

Table 7 Possible Valve Layer Attributes

Attribute	If not set
diameter valve_type minor_loss initial_status Initial_setting	Required ‘PRV’ 0 Active