Planning considerations - Living Roofs in Integrated Urban Water Systems - page 51

organic fertilizer is used, discharge may carry high nutrient content (phosphorus
and nitrogen). This can be a potential problem for freshwater receiving environ-
ments, if discharged without treatment.
The roof area can also be used for the generation of renewable energy, using
solar energy to generate electricity with either photovoltaic cells for the building
(including irrigation pumps or automatic leak detection devices in the water-
prooing membrane) and/or the city grid, or solar- water heating collectors to
create hot water for the building. Additionally, wind turbines can be installed on
the roof to generate renewable energy, although in cities they are considered
problematic for various reasons, including lack of eficiency, noise and aesthetics
(Dutton et al. 2005; Wilson 2009). 1 In any case, these additional structures must
be installed above the living roof vegetation to avoid a large reduction in storm-
water mitigation capacity.
The evolution of design should never conlict with the roof's performance
objectives. For example, logistical aspects of living roof design (including access
to services, like water and electricity, as well as maintenance access and
maintenance access safety, i.e., location of guardrails, roof tie-off points, etc.)
should take place in conjunction with planting design, because the design
elements in question may interfere with the planting performance and/or
experiential design.
3.2.1.1 Client involvement in planning process
Informing the client regarding all aspects of the project is an important responsi-
bility of the design consultant team described in codes of architects' and land-
scape architects' professional associations. The design consultant team should
consult the client for developing project objectives and roof design, to clarify
expectations and avoid misunderstandings, especially regarding budget and the
appearance and maintenance of a living roof after it has been constructed. The
client should be regularly informed with presentations by the design consultant
team about the planning and construction process, explaining the following
topics:
• How design objectives have been implemented. For example stormwater
runoff performance, year-round appearance of living roof, e.g., vegetation
cover, color, height or balancing design elements to ensure adequate
rainwater capture to ill roof-irrigating cisterns while maximizing “greened”
area.
• What changes are occurring during the planning process. For example, if
modiication of the roof structure is needed to accommodate the intended
plant palette, or if a proposed cistern must be enlarged to hold enough water
to irrigate the roof during the dry periods, which has implications on space
and loading of the building structure.
• How the project is detailed, for example to describe weathering, durability
and ecological footprint of materials.