Cities and Water: Sinks or Sponges?

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Cities and Water:
Sinks or Sponges?
16th International River Symposium
Brisbane, 23 September 2013
Jeremy Bird
Internation...

• More than half of
the world’s
population lives in
urban areas.
• Urban growth is
most rapid in
developing
countries: cit...

What is urban?
What is rural?
Accra:
the administrative
boundary is
outpaced by urban
sprawl

Map of
population
density
South Asia exemplifies urbanization challenges and
rural-urban tensions
http://pricetags.files.w...

Example: New Delhi
1974 1999 2013

Time for a new approach….
“For most of the last century, economic growth was
fuelled by what seemed to be a certain truth:...

Urban unit
• Supply infrastructure
• Sewage infrastructure
Wastewater disposal
• Receiving water bodies
• Use in irrigated...

Urban expansion, Hyderabad, India
Source: Wikimedia Commons

Pulling water in from an increasing distance
Hyderabad, India
Krishna River
Himayat Sagar
Osman Sagar
GW
Musi River
GW – G...

Change in water sources to satisfy urban needs
Hyderabad Water Supplies and Demands
Osman Sagar Himayat Sagar
Ground Water...

Informal water markets on the increase
• No Indian city has a 24/7
water supply.
• Demand for tanker supply
on the increas...

Groundwater
extraction in
India:
Urban needs add
to existing stress
from agricultural
use

Examples of water transfers exist
…as allocation to
agriculture reduced
and transferred to
urban use
Agricultural
producti...

Reflections : Cities as a water sink
• Footprint of urban expansion on water for irrigation can be
extensive - depends on ...

What happens to the urban ‘return’ flow?
Urban unit
Wastewater
disposal
Water source
wastewater treatment?

In most cities in sub-Saharan Africa, S. Asia and SE Asia, population
growth has outpaced the development of sanitation in...

$Sewer networks collect only a tiny fraction of city wastewater. The few wastewater treatment plants that exist are often o...$

This leads to severe water pollution in peri-urban areas

Wastewater
Piped water
Also an opportunity?

Due to the proximity of markets and lack of
refrigerated transport and storage, a whole
irrigation sub-sector specialized ...

In the economically important
rural–urban interface, it is difficult
to find a reliable unpolluted water
source.

0
5
10
15
20
25
30
Diluted
wastewater
or polluted
water
Untreated
wastewater
Groundwater Treated
wastewater
River Other
su...

Water quality improves over 40 km along the Musi River
Hyderabad
Sources: IWMI/J. Ensink

IWMI works closely with WHO and FAO on safe
wastewater reuse
• Assessing the extent of reuse, risks and benefits.
• Develo...

• health risk mitigation
measures have a RoI
of U$4.9 for each
dollar invested.
Mitigating risks where wastewater
treatmen...

Australia: National target of 30% of wastewater
being recycled by 2015
%
Source: Marsden Jacob Associates 2012

Reflections II : Cities as sponges
• Wastewater reuse can minimize risks of urban areas becoming
water sinks and contribut...

Urban food demands and waste generation
mirror the same challenges
Source: Wikimedia Commons

Source: IWMI
!?
Import/
Export
Livestock
Food
Food crops
and fodder
plants
Soil
nutrients
Organic solid
waste,
sludge &
wa...

Closing the loop is no easy endeavor in the
rural-urban context
Technical solutions for resource
recovery are available, b...

Resource Recovery & Reuse (RRR)
A research flagship of CGIAR-WLE using a business approach to
attract private capital
Old ...

New understandings required to close the loop

RRR program for water, nutrient and
energy recovery from domestic and agro-industrial waste
 Database of 150+ inspiring R...

Example of a business model currently being implemented
in Ghana as a Public-Private Partnership:
Fecal Sludge Valorizatio...

Introducing business models to turn
waste into an asset
• Solid waste and fecal sludge
composting in Asia and Africa
could...

Some ‘nexus’ implications
Energy reduction in
• Water treatment
• Chemical fertilizer
production and
transport
Environment...

Addressing water challenges of rapid urbanization
• Analysis: expand inter-sectoral perspective at basin scale to
include ...

www.iwmi.org/Topics/RRR http://wle.cgiar.org/RRR
Closing the loop

Cities and Water: Sinks or Sponges?

Cities and Water: Sinks or Sponges?

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