Treatment MeasuresRooftop Greening : Case Studies

More Information

R.M.I.T Tivoli Rooftop

Overview

RMIT University was invited by the City of Melbourne to participate in a project that is to demonstrate improved practices in the management of stormwater in a central city setting. RMIT University responded with a project that converted 720m² of outdoor plaza into a garden for the purpose of harvesting the rainwater for reuse in toilets throughout the building and irrigation for the garden.

The project cost is estimated at $228,500, taking into consideration that the project submission quoted an Environmental Engineer from Scott Wilson Irwin Johnson "the majority of necessary infrastructure for stormwater collection is already in place....". This would impact upon the quoted project cost but may give a retro-fit comparison for project of similar parameters.

The City and its trading partners and commercial providers are beneficiaries of the presence of RMIT students located in this building and using the garden area. The local businesses are where the students, staff meet, relax and enjoy all that the City offers. This garden area encourages the students to use and enjoy the city.

Design Considerations

A current development is the Rooftop greening and reuse of rainwater on the Tivoli building of Royal Melbourne Institute of Technology (RMIT) City campus. This project will collect rainfall from the roof, store the water in an underground tank and pump it back to the roof header tanks as 'grey water' for toilet flushing. The harvested water will also be reused for garden irrigation on the rooftop to conserve potable freshwater resources and make a functional and amenable plaza area for students.

The location of the project

An aerial photograph visually highlighting the location of the building within the Melbourne CBD and its relative proximity to features.

Schematic of Proposed Greywater System

A simple schematic drawing of the building and how the water is captured and stored for the future reuse

Maintenance

Maintenance for this type of treatment measure is dependent upon the parameters used in the design. In addition the size of the garden will dictate the maintenance time.

Issues related to the maintenance of rooftop gardens and the subsequent management of water including its reuse would be managed by usual building maintenance. The periodical monitoring by qualified personnel would be required to achieve maximum results.

The extra specialists required for such aspects, as part of a new development would be a horticulturalist. Such an expert would provide the knowledge of specific biological aspects that will successfully be incorporated into the design of the rooftop garden.

The retro-fit of existing buildings would require the sessional employment of engineers, plumbers, electricians, landscapers and a horticulturist. In addition to the personnel substrate/ membrane, plants, tanks, plumbing fittings, pumps and timers, irrigation, soils, electrical fittings and audit expenses are parameters to be taken into account when the feasibility of such a development is evaluated.