Active open space

The active open space node assigns the said land use to a specific GIS-delineated area: this involves (1) the generation of urban form with a likeness to that occupying the land use zone in question, (2) alteration of the land cover within the region, and (3) employment of a unique water demand profile for the parcels created as part of the zoning.

The initial urban form abstraction utilises the workflow that comprises the residential node, with the corresponding parameters fixed so that the properties of the blocks, parcels and buildings that are generated reflect an idealised area of active open space land use.

Table 1. Fixed residential node parameters

Parameter

Value

Units

City block width

10*10^20

m

City block length

10*10^20

m

Street offset

10*10^-5

m

City parcel width

10*10^20

m

City parcel height

10*10^20

m

Hardstand fraction

0.1

Irrigation ratio

1

Block and parcel dimensions are set at maximums and street offset is set at the minimum in order to engender a representation of a continuous piece of land within which an active open space area exists for each feature of the GIS data layer the node is used with. The assumption in this case is that the location and extent of any discrete active open space region would be specified by the existence of a corresponding layer feature that was part of the data layer, and thus there is no requirement to generate streets or multiple blocks or parcels within the features.

The land use’s hardstand fraction is inherited from Melbourne Water’s MUSIC Modelling Guidelines (Melbourne Water 2018) – the hardstand area is assumed as impervious fraction; the irrigation ratio is the default of that of any actively irrigated open space.

It is to be noted that the node’s workflow does not exactly follow that of the base residential node – the operations responsible for generating new trees are removed, and functionality that removes any existing trees intersecting the region of interest is introduced.

Following the urban form characterisation, the microclimate grid is updated to reflect the nature of the land cover of the zone. The microclimate grid proportions are indicative of the information prompting the parcel hardstand fraction and irrigation ratio values, and are applied to the entire region used by the adaption node.

Table 2. Land cover proportions

Land cover

Fraction of microclimate grid cell

Tree

0.00

Water

0.00

Dry Grass

0.00

Irrigated Grass

0.9

Roof

0.00

Road

0.00

Concrete

0.1