Page 513 - Shaping smarter and more sustainable cities - Striving for sustainable development goals

1 Introduction

The Water cycle (water resource, production, distribution, consumption, collection and treatment
of waste water) play an integral part of the urban system, influencing each pillar of the urban society
and its functionality, sustaining populations, generating energy, supporting tourism and recreational
activities, ensuring environmental and human health, and fuelling local economic development.
Such increasing convergence fosters urban growth, as more than half of the world's population
1
currently reside in urban areas . It is estimated that urban populations will increase from 3.6 billion
2
in 2011, to 6.3 billion in 2050 . Urban areas will also have the task of absorbing rural populations, as
their growth continues to decline.
As illustrated in Figure 1, the availability and distribution of water resources is intrinsically linked to
the city's operations in areas as diverse as housing, health, economic development, tourism,
recreation, transport, waste management and energy.

3
Source: Howe et.al. (2011).
Figure 1 – Interconnectedness of water and cities
The increasing concentration of people, economic activities and assets in urban areas usually
generates high amounts of waste and greenhouse gas pollution, heightening the city's susceptibility
to the risks posed by disasters/hazards, as well as to the impacts of climate change. Thus, unbridled
growth in urban areas poses socio‐economic and environmental challenges to residents, businesses,
industries, municipalities and governments alike. As per the focus of this Technical Report, it also
poses significant challenges to urban planners in terms of effective and sustainable water
management.

ITU‐T's Technical Reports and Specifications 503