What Are the Main Options for Applying the Multiple-Use Water Services Paradigm? - Rethinking Infrastructure Design for Multi-Use Water Services - page 33

Fig. 5 A green wall (left) and a green fa ç ade (right) in Melbourne (Source DEPI ( 2014 ))

Facts A 2006 study conducted by the University of Michigan compared the
costs and benefits, including storm water management and public health
improvement, of a 21,000 sq.ft. green roof over a conventional roof. The
results showed that the installation of the green roof would cost $464,000,
while the conventional one $335,000 (in 2006 values). However, it was
estimated that the green roof would save more than $200,000 during its
lifetime, with two-thirds of that savings resulting from reduction in energy
needs (Clark et al. 2008a , b ).

5.3 What Are Green Walls?

Green walls, also known as living walls, bio- or eco-walls are vertical plants either
grown on freestanding structures or attached to interior or exterior walls (DEPI
2014 ). They are composite systems incorporating plants, growing medium, drain-
age, irrigation and often fertilisation. They can retain a great variety of vegetation
depending on local climatic conditions. In green walls, the whole structure is plated
compared to green fa ades where climbing plants are used, which are either rooted

in the ground at the bottom of the structure or are planted in boxes at different levels
and cover a part or the entire surface of a building. However, green wall is a general
term used for interior or exterior vertical vegetated surfaces (GRHC 2014 ). They are
usually designed for aesthetic purposes but they can provide additional bene

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ts
such as enhanced interior and exterior air quality, thermal insulation and higher
property values (Fig. 5 ).