Case Studies Illustrating the Multiple-Use Water Services Options - Rethinking Infrastructure Design for Multi-Use Water Services - page 69

1.1 What Is the Challenge?

The complete dependence of Seoul s water supply and drainage on a centralised

system is unstable in view of climate change, increased urbanisation rates and the
energy crisis. Water supply reliability is further challenged by the ageing infra-
structure and increasing energy costs. Urban

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flooding risk has increased since the
uptake of open spaces has increased run-off from 9 % (in pre-development) to 47 %
and decreased infiltration from 40 to 23 %. Urban heat island effects are observed.
Moving towards decentralised water management and developing such systems can
reduce the prevailing risks.

1.2 What Is the Policy Framework?

The first law to promote Rainwater Harvesting and Management (RHM) in Korea is

the (2001), which forces sport facilities with roof area larger than

2,500 m 2 to have rainwater harvesting systems (RHS) (Han and Park 2005 ). Four
world cup stadiums in Korea have been accordingly equipped under this Law, while
numerous RHM projects have emerged. In 2010, the

' Water Law '

' Law to promote and support

water reuse released by the Ministry of Environment, puts into effect the instal-

lation of RHS for non-potable uses. The policy development by municipalities is
much more active than that by the central government in Korea. While no ordinate
for RHM existed prior to 2003, 26 ordinates were adopted from 2004 to 2008, 19
more from 2008 to 2009 and as of July 2010, 47 ordinances exist for RHM by the
municipalities. These vary in scope, the early ones focusing on rainwater storage
and use, progressively expanding their focus to

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flood control (e.g. Seoul, Daejeon,
Incheon cities) and further to integrated water management for restoring the
hydrologic cycle (e.g. Suwon city) (UN ESCAP 2012 ). Various types of incentives
have been promoted in parallel to secure the uptake of the ordinances: Seoul city

financially supports the installation of RHS (up to 10 million won), Jeju island
provides subsidies covering up to 80 % of total installation costs, some munici-
palities lower the costs of tap water supply and wastewater treatments for the people
who use RHS, others reward a higher floor space index allowance to buildings with

RHS (UN ESCAP 2012 ).
The paradigm of RHM is continuously evolving, currently supporting the multi-
bene

flood mitigation, water con-
servation, non-point source pollution control, hydrologic cycle restoration and
urban heat island phenomena alleviation (UN ESCAP 2012 ).

t integrated rainwater management for urban