School

The school 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 school land use. The set parameters are informed by multiple sources, including Vicmap Planning land use data and PSMA’s building footprint and cadastral datasets.

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

Site coverage

0.2

Hardstand fraction

0.63

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 a school 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 individual school 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.

Site coverage was taken as the building coverage ratio (BCR) established for the land use through analysis of the Vicmap Planning zoning and PSMA cadastral/building data.

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 minus roof fraction, which is taken as the BCR; the irrigation ratio is the default of that of any actively irrigated open space.

Building length and width was decided upon through the use of the building coverage ratio (BCR) deduced from the analysis of the PSMA cadastral and building data – the parcel area resulting from the respective cited length and width inputs is multiplied by the BCR to establish an approximate idealised building size. Then, building dimensions which serve to most closely replicate the aspect ratio of the characterised parcel are chosen to engender this said area (building height is taken as the median denoted as part of the building footprint dataset).

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, functionality that removes any existing trees intersecting the region of interest is introduced, and a module that serves to set the number of students accommodated by each layer feature that is part of the data layer utilised with the node is incorporated into the workflow.

The student count module functions in one of two ways: either the number of students per layer feature is calculated based on a formula, or, if a total student count for the adaptation region is entered, this figure is distributed equally between all layer features. All student counts are rounded to the nearest integer, and a negative value for the total number of students cannot be entered (the value resets to zero).

../_images/zoning_formula_1.png
Table 2. Student count calculation variables

Variable

Value

Description

N_E

Number of employees calculated for the given layer feature

N_F

Median building height divided by assumed floor height

B_H

5.48

Median building height

F_H

4

Assumed floor height

A_F

Area of the light industrial layer feature in square metres

BCR

0.2

Building coverage ratio (i.e. what proportion of the lot is covered by the building footprint)

R_C

0.25

Ratio of classroom roof area to total roof area

NUAR

0.65

Net usable area ratio (i.e. the proportion of practical usable area within a building)

CF

1.3

Compliance factor (estimation of the tolerance given to the area per person value)

A_P

2

Area per person (i.e the floor space of a building required for every occupant) in square metres

The median building height for the land use (established through investigation of the corresponding Vicmap Planning and PSMA datasets for a Melbourne LGA) was used as part of determining the number of floors of a building (a storey was taken as four metres, per the assumption used by the Department of Planning and Community Development); the classroom ratio was assumed from calibration against real-world student numbers for schools; net usable area and area per person were taken from The Architect’s Handbook (Pickard 2008) and the Building Code of Australia (ABCB 2016), respectively (the compliance factor was calculated by dividing the recommended area per person for an office from the former, by the minimum area per person from the later).

Following the urban form characterisation and the allocation of students to the layer features specific to the land use zone, 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 3. Land cover proportions

Land cover

Fraction of microclimate grid cell

Tree

0.00

Water

0.00

Dry Grass

0.00

Irrigated Grass

0.3

Roof

0.2

Road

0.00

Concrete

0.5

The final element of the school adaptation node involves the assignment of the said land use zone to a zoning attribute attached to the parcel – the attribute is used to filter for a water demand model profile specific to the land use in question.

Table 4. End-use demand rates

End-use

Demand rate

Units

Leakage

0

L/p/d

Washing machine

9.05

L/p/d

Tap

8.23

L/p/d

Toilet

37.01

L/p/d

Shower/bath

0

L/p/d

The end-use terms for the demand profile are in litres per capita per day, and are calculated by first establishing a gross demand rate for the land use – in this case, this is done through referencing ‘The Water Encyclopedia: Second Edition’ (van der Leeden et al. 1990) and taking the day student demand (it was assumed that schools characterised by the node do not possess a swimming pool, do not have students take showers on campus, and utilise a kitchen or a cafeteria). The cited daily per capita rate is then scaled down to account for the working week and partitioned according to reports ’Waste Not, Want Not: The Potential for Urban Water Conservation in California’ (Cain et al. 2003) and ‘Water Efficiency in the Commercial and Institutional Sector: Considerations for a WaterSense Program’ (EPA 2009), published by the Pacific Institute and the EPA, respectively. From the reports, water for heating and cooling was taken as equivalent to the washing machine end-use.