What Are the Main Options for Applying the Multiple-Use Water Services Paradigm? - Rethinking Infrastructure Design for Multi-Use Water Services - page 32

Extensive Semi-Intensive Intensive

Depth of growing

3 - 5 inches 5 - 7 inches 7 - 24+ inches

medium

Weight max. 15- 25 lbs/ft 2 25- 40 lbs/ft 2 35 - 80+ lbs/ft 2

sedums, small grasses, herbs selected perennials, sedums,

perennials, lawn, shrubs and

Plants and flowering herbaceous ornamental grasses, herbs and

small trees, rooftop farming

plants small shrubs

Irrigation Not recommended Occasional irrigation Advanced irrigation systems

low medium high

Maintenance

Use Living machine Diversity, habitat Garden, park

Costs low medium high

Fig. 3 Types of green roofs (Source Adapted from http://www.greenrooftechnology.com )

Fig. 4 Typical green roof
layers (Photo courtesy
American Hydrotech, Inc.
Source Tolderlund ( 2010 ))

installing a green roof in a new construction costs less than retro tting (Peck and

Kuhn 2003 ). The installation of an extensive green roof with root repellent/
waterproof membranes may cost around $10

$24 US/sq.ft. (GRHC 2014 ). Green
roofs are more expensive to construct than conventional roofs but they can be more
cost-effective in the end due to extending the life span of the roof membrane and
leading to signi

-

cant energy savings from heating and cooling.