SL5 final report World Association of the Major Metropolises Alexandre Désiré MVONDO Contributor 2024 The Solution Lab on cities under water stress

Final report

Solutions Lab #5: Cities
Under Water Stress

page 1

List of tables
Table 1. Main causes of water stress and scarcity in big cities.
Table 2. The governance of the water sector in Barcelona.

List of figures
Figure 1. Country-level water stress in 20240 projections.
Figure 2. World pap of water stress using the Water Stress indicator.
Figure 3. Trends in all big cities and water stress ratings.
Figure 4. Location of cities participating in the Metropolis Solutions Lab #5 online sessions.
Figure 5. BCASA’s strategic areas of operation.
Figure 6. Internal basins of Catalonia.
Figure 7. Forecast for water needs in Barcelona Metropolitan Area (5,3 million inhabitants).
Figure 8. Water Cycle Master Plans.
Figure 9. Uses of groundwater and other alternative water resources.
Figure 10. Example of educational and awareness program in Barcelona.
Figure 11. Evolution of water consumption in Barcelona..
Figure 12. Location of Cape Town and view of the city.
Figure 13. Campaign informing the population on Day Zero.
Figure 14. Examples of the communication campaign “Save Like a Local”.
Figure 15. Meeting of the WCWSS Water Users Platform.
Figure 16. Interfaith group meeting.
Figure 17. Location of Douala. Water supply network and infrastructures.
Figure 18. Wastewater treatment plant facilities in Douala.
Figure 19. Cover of the National Strategy for Promoting Access to Drinking Water, Hygiene,
and Sanitation in Schools in Cameroon.
Figure 20. Location of Montevideo and map of the city.
Figure 21. Effects of drought in Paso Severino dam infrastructure.
Figure 22. Oceanic Niño Index (ONI) for Uruguay.
Figure 23. Mixture of water with different composition.
Figure 24. Cover of the first plan of Integrated Risk Management of Montevideo.
Figure 25. Cover of the Montevideo Climate Action Plan.
Figure 26. Location of San Francisco and view of the city.
Figure 27. Public services provided by SFPUC.
Figure 28. Hetch Hetchy Regional Water System, services of SFPUC.
Figure 29. Drought in California.
Figure 30. SFPCU’s diversification of water sources.
Figure 31. Examples of public awareness campaigns and public assistance.
Figure 32. Cover of the publication Resilience in Action. Public Water Operators’ Strategies to
Tackle Water Scarcity and Drought (APE).

page 2

Abbreviations and acronyms
AMB
APE
AWF
BCASA
CAMWATER
CIF
CRP
CWRA
EDP
EIB
ENSO
EU
GCoM
GEF
GFC
GWOPA
ICLEI
IDB
NGO
ONI
PDISBA
PELARHAB
PPP
RCN
SFPUC
SUDS
TAP
UN
UN-HABITAT
USA
WCWSS

Metropolitan Area of Barcelona
Aqua Publica Europea
African Water Facility
Barcelona Water Cycle
Cameroon Water Utility Corporation
Climate Investment Funds
City Resilience Program
City Water Resilient Approach
Economic Development Partnership
European Investment Bank
El Niño/Southern Oscillation
European Union
Global Covenant of Mayors for Climate and Energy
Global Environment Facility
Green Climate Fund
Global Water Operators’ Partnerships Alliance
Local Governments for Sustainability
Inter-American Development Bank
Non-governmental Organization
Oceanic Niño Index
Sanitation Master Plan
Alternative Water Resources Master Plan
Public-private Partnerships
Resilient Cities Network
San Francisco Public Utilities Commission
Sustainable Urban Drainage Systems
Transformative Actions Program
United Nations
United Nations Human Settlements Programme
United States of America
Western Cape Water Supply System

page 3

Contributors
Andrea De Nigris, Montevideo City Council (Montevideo, Uruguay),
Andrew Boraine, Independent Partnering Practitioner (Cape Town, South Africa),
Angoni Davy Bertrand, Douala City Council (Douala, Cameroon),
Israel Barroso (Metropolis staff),
Jose Luis Martin-Bordes (Expert and facilitator),
Maria Jose Chesa Marro, Barcelona Water Cycle (BCASA) (Barcelona, Spain),
María Mena, Montevideo City Council (Montevideo, Uruguay),
Marine Boulard, Aqua Publica Europea,
Milo Fiasconaro, Aqua Publica Europea,
Mvondo Mvogo Alexandre Désiré, Douala City Council (Douala, Cameroon),
Paula Keho, San Francisco Public Utilities Commission (San Fancisco, USA)
Priya Reddy, City of Cape Town Municipality (Cape Town, South Africa)

Disclaimer
This report summarizes discussions from the Metropolis Solutions Lab #5, held between
September and October 2024, with contributions from five cities and European public
water operators.
The insights, strategies, and recommendations reflect participants' perspectives and do
not necessarily represent Metropolis or its members. While highlighting innovative
practices, this report does not endorse specific policies, projects, or funding mechanisms.
Metropolis is not responsible for the accuracy or applicability of the information. Readers
should conduct further research and consult relevant stakeholders before
implementation.
Drafted by Jose Luis Martin-Bordes, February 2025.

page 4

Table of contents
List of Tables...........................................................................................................................................1
List of Figures..........................................................................................................................................1
Abbreviations and Acronyms............................................................................................................... 2
Executive Summary............................................................................................................................... 5
1. Introduction......................................................................................................................................6
2. Water scarcity and stress in cities.................................................................................................7
3. Cities Case studies.........................................................................................................................11
3.1 City of Barcelona, Spain.........................................................................................................12
3.1.1 Comprehensive overview of Barcelona Water Cycle...............................................12
3.1.2 Water stress context and main challenges...............................................................13
3.1.3 Strategies and solutions to manage water scarcity.................................................16
3.1.4 Key lessons....................................................................................................................19
3.2 City of Cape Town, South Africa............................................................................................20
3.2.1 Comprehensive overview of the City of Cape Town Municipality..........................20
3.2.2 Water stress context and main challenges............................................................... 22
3.2.3 Strategies and solutions to manage water scarcity................................................. 22
3.2.4 Key lessons.....................................................................................................................27
3.3 City of Douala, Cameroon......................................................................................................28
3.3.1 Comprehensive overview of Douala City Council.................................................... 28
3.3.2 Water stress context and main challenges............................................................... 29
3.3.3 Strategies and solutions to manage water scarcity................................................. 30
3.3.4 Key lessons.................................................................................................................... 32
3.4 City of Montevideo, Uruguay.................................................................................................33
3.4.1 Comprehensive overview of Montevideo City Council............................................33
3.4.2 Water stress context and main challenges............................................................... 34
3.4.3 Strategies and solutions to manage water scarcity................................................. 36
3.4.4 Key lessons.....................................................................................................................38
3.5 City of San Francisco, USA......................................................................................................39
3.5.1 Comprehensive overview of San Francisco Public Utilities Commission..............39
3.5.2 Water stress context and main challenges............................................................... 41
3.5.3 Strategies and solutions to manage water scarcity................................................. 43
3.5.4 Key lessons.................................................................................................................... 45
3.6 The experience of European water operators addressing water scarcity Aqua Publica Europea (APE).................................................................................................. 46
4.Key recommendations................................................................................................................... 49
Annex I: Cities’ infographics................................................................................................................ 51
Annex II: Opportunities for financing cities’ water resilience.........................................................52

page 5

Executive summary
By 2030, global freshwater demand is projected to surpass supply by 40%, driven by climate
change, population growth, and human activity. Rapid urbanization, which has increased
urban populations from under 1 billion in the 1950s to over 4 billion by 2020, intensifies
water stress in metropolitan areas. Currently, nearly 1 billion urban residents face water
scarcity, with projections indicating this number could rise to 2.4 billion by 2050. The
expansion of urban populations, alongside increasing per-capita water usage, places
immense strain on water resources, infrastructure, and water quality. Studies show that
44% of major cities face high to very high-water stress, with 35% of megacities already
vulnerable to shortages. Key causes include climate change, groundwater over-extraction,
aging infrastructure, pollution, and unequal distribution. Cities like São Paulo, Cape Town,
San Francisco, Bogotá or Barcelona have experienced severe crises, highlighting the need
for proactive, integrated water management strategies. Ensuring a sustainable and
equitable water future requires immediate action, collaboration, and innovation to build
resilience against escalating water challenges.
Three online sessions were held under the Metropolis Solutions Lab #5 between September
and October 2024, aimed at exploring and advancing innovative strategies to address water
stress challenges in metropolitan areas. This report showcases the strategies, solutions, and
lessons learned from the participating cities - Barcelona, Cape Town, Douala, Montevideo,
and San Francisco - while also incorporating insights from a network of European public
water operators.

page 6

1. Introduction
This report presents the outcomes of three online sessions held under the Metropolis
Solutions Lab #5, designed to explore and advance innovative strategies for tackling water
stress challenges in metropolitan areas. The sessions, held in September and October 2024,
brought together representatives from five cities - Barcelona, Cape Town, Douala,
Montevideo, and San Francisco - who shared valuable insights into the solutions adopted
within their unique contexts and the lessons learned from their experiences.
The specific objectives of the Metropolis Solutions Lab #5 were to:
Explore strategies for preventing and mitigating the impacts of water stress in
metropolitan regions.
Foster collaboration and facilitate the exchange of best practices among participating
cities.
Co-develop tailored recommendations for water stress management in the participating
territories.
Present funding opportunities for projects aimed at addressing water stress in urban
environments.
This report highlights some of the most innovative ideas and solutions discussed during the
sessions, aiming to promote the wider adoption of effective practices and to strengthen
collaborative efforts among cities worldwide. Following this knowledge-sharing initiative, the
Metropolis Secretariat General will conduct targeted follow-up assessments to evaluate how
participating cities are implementing the proposed solutions and initiating new projects.
Additionally, insights gained from these follow-up assessments will inform the work of the
Metropolis Investment Forum for Sustainable Metropolises. This platform, designed to
connect cities seeking project funding with potential donors, will leverage the knowledge
generated through Solutions Lab #5 to identify and support tailored funding opportunities.
This approach ensures that each city's specific needs are addressed, facilitating the
development and implementation of robust water stress management strategies.

page 7

2. Water scarcity and stress in cities
By 2030, global demand for freshwater will outstrip supply by 40%, driven by the
1
compounding effects of climate change, human activity, and population growth. Water
scarcity arises when communities cannot meet their water needs due to insufficient
supplies or inadequate infrastructure.
While climate change exacerbates water scarcity, societal and economic activities, coupled
with increasing urbanization and population densities, have compounded challenges in
managing water resources. Rapid urbanization has seen a significant shift, with less than a
billion people living in urban areas in the 1950s to over 4 billion by 2020. According to the
UN World Water Development Report, currently, almost 1 billion urban residents globally
experience water scarcity, a number projected to rise to between 1.7 billion and 2.4 billion
in the next 30 years.2 Projections for 2050 suggest an additional 2.6 billion urban dwellers,
3
further straining water resources.
The demand for adequate water supply has surged due to residential needs, resulting in a
4
rise in per-capita water usage. In cities and metropolitan territories, with the actual
projected trends of population growth compounded with climate change impacts, proactive
measures are essential to enhance their resilience and those of their water systems
management. Those challenges include water quantity but also water quality and
addressing infrastructural deficiencies to ensure an integral approach to managing water
resources effectively, securing reliable water supply, and mitigating the impacts of water
stress.
The graph suggests that under current climate conditions, 44 % of the Big Cities face Highto Very High-water stress (Figure 3). In a study of 71 Cities with more than 750 000
inhabitants, it was estimated that 35 % of the Megacities are presently vulnerable to water
shortages.5
resources

1. https://www.theguardian.com/environment/2023/mar/17/global-fresh-water-demand-outstrip-supply-by-2030
2. The United Nations World Water Development Report 2023
3. https://www.un.org/development/desa/en/news/population/2018-revision-of-world-urbanization-prospects.html
4. https://www.sciencedirect.com/science/article/pii/S0959378014000880
5. https://wad.jrc.ec.europa.eu/waterstress

page 8

Figure 1. Country-level water stress in 2040 projections

6

Figure 2. World pap of water stress using the Water Stress indicator. (Source Aqueduct Global Maps)
1. x
2. x
3. x
4. x
5. X
6. Luo, T., R. Young, P. Reig. 2015. “Aqueduct Projected Water Stress Country Rankings.” Technical Note. Washington,
D.C.: World Resources Institute. Available online at: www.wri.org/publication/aqueduct-projected-water-stresscountry-rankings
7. https://wad.jrc.ec.europa.eu/waterstress

7

page 9

Figure 3. Trends in all big cities and water stress ratings (Source Reynolds, J. et al)

8

Water stress and scarcity in big cities and metropolises stem from a combination of
environmental, demographic, and infrastructural factors. Here are the main causes:

Table 1. Main causes of water stress and scarcity in big cities.
Cause

Description

Rapid urbanization
and population
growth

The fast-paced growth of cities increases water demand for residential,
industrial, and commercial use. As populations expand, municipal water
systems often struggle to keep up with the rising consumption.

Climate change
and extreme
weather

Climate change intensifies droughts, reduces rainfall, and disrupts
seasonal weather patterns. In contrast, extreme rainfall can lead to flash
floods, overwhelming infrastructure and preventing proper water
storage.

1. x

2. x
Over-extraction
of
3. x
groundwater

To meet urban demand, cities often overdraw groundwater resources.
This unsustainable extraction leads to aquifer depletion and land
subsidence, further complicating water management.

4. x
5. Luo, T., R. Young, P. Reig. 2015. “Aqueduct Projected Water Stress Country Rankings.” Technical Note. Washington,
D.C.: World Resources Institute. Available online at: www.wri.org/publication/aqueduct-projected-water-stresscountry-rankings
6. https://wad.jrc.ec.europa.eu/waterstress
7. https://wad.jrc.ec.europa.eu/waterstress
8. https://wad.jrc.ec.europa.eu/waterstress

page 10

Table 1 cont.
Cause

Description

Aging and inefficient
infrastructure

In many cities, outdated water supply systems result in significant water
losses through leaks and pipe bursts. The World Bank estimates that
nearly 30% of urban water is lost due to aging infrastructure.

Pollution of water
sources

Industrial discharge, agricultural runoff, and untreated sewage
contaminate surface and groundwater sources. This reduces the
availability of clean water for urban consumption.

Unequal distribution
and poor
management

Socioeconomic disparities often result in unequal access to water.
Wealthier neighborhoods may enjoy continuous supply, while poorer
areas face frequent shortages and rely on expensive alternatives.

Competition
between sectors

Urban, agricultural, and industrial sectors often compete for limited
water resources. This competition intensifies during periods of drought,
straining urban supplies.

Insufficient storage
and recycling

Many cities lack adequate infrastructure to store rainwater or recycle
wastewater. Without proper storage and treatment facilities, valuable
water resources go unused or become contaminated.

Political and
institutional
challenges

Poor governance, corruption, and lack of long-term planning further
exacerbate water stress. Effective water management requires
coordinated efforts across municipal, regional, and national levels.

Changing
consumption
patterns

Rising living standards in urban areas often lead to higher per capita
water consumption, putting additional pressure on already strained
water systems.

page 11
In recent years, we have seen numerous global cities and metropolitan areas, including Sao
9
10
11
12
Paulo, Cape Town, Bogotá and Barcelona, grappling with severe water stress crises. The
strategies they have employed to manage these crises provide valuable lessons on crafting
and executing effective solutions to alleviate the impacts of water stress.
As water stress becomes more frequent and intense, coupled with rising water demand,
cities and metropolitan regions must devise and implement sustainable strategies to tackle
it. Addressing this crisis requires immediate action, collaboration, and the introduction of
innovative solutions to ensure a sustainable and fair water future for the generations to
come.

3. City case studies
Five cities across three continents - Barcelona, Cape Town, Douala, Montevideo, and San
Francisco - in the Metropolis Solutions Lab #5 online sessions held in September and
October 2024. The diverse climatic, geographic, socioeconomic, demographic, and
infrastructural contexts shaping water stress in these cities provided a unique platform for
comparative analysis. This diversity enabled a comprehensive exploration of the varied
strategies employed to address water scarcity, highlighting both common challenges and
context-specific solutions.
The participating cities shared their experiences in developing technical innovations,
establishing financial mechanisms, and launching creative communication campaigns to
raise awareness and drive action. These approaches serve as valuable models for other
metropolitan regions seeking to design and implement their own water stress management
strategies. The following section presents a concise summary of each city’s case study,
offering insights into the practical solutions and lessons learned that can inspire broader
adoption and adaptation in diverse urban contexts. Furthermore, the report highlights
several examples of European cities implementing effective strategies to tackle water
scarcity.
1. x
2. x
3. x
4. x
5. Luo, T., R. Young, P. Reig. 2015. “Aqueduct Projected Water Stress Country Rankings.” Technical Note. Washington,
D.C.: World Resources Institute. Available online at: www.wri.org/publication/aqueduct-projected-water-stresscountry-rankings
6. https://wad.jrc.ec.europa.eu/waterstress
7. https://wad.jrc.ec.europa.eu/waterstress
8. x
9. https://www.wri.org/insights/3-maps-help-explain-sao-paulo-brazils-water-crisis
10. https://www.weforum.org/agenda/2019/08/cape-town-was-90-days-away-from-running-out-of-water-heres-how-itaverted-the-crisis/
11. https://www.theatlantic.com/science/archive/2024/12/bogota-drought-water-rationing-routine/681023/
12. https://www.euronews.com/green/2023/04/19/barcelona-is-heading-for-a-drought-emergency-as-water-shortagesworsen

page 12

Figure 4. Location of cities participating in the Metropolis Solutions Lab #5 online sessions.

3.1 City of Barcelona, Spain
3.1.1 Comprehensive overview of the Barcelona Water Cycle
Barcelona, a city of one million residents and over 15 million annual visitors, faces
significant challenges in water management, particularly as climate change intensifies
pressure on its water supply. Barcelona Water Cycle (BCASA) is a municipal 100% public
company incorporated in 2014 and integrated into the Area of Ecology, Urban Planning and
Mobility at Barcelona City Council. BCASA provides services centered on the Comprehensive
Water Cycle and operates in four strategic areas: supply, urban drainage and sewerage
system, coastal management and other support initiatives in the cycle, serving 1.6 million
city residents and over 15,6 million visitors a year (2023) (Figure 5).

Figure 5. BCASA’s strategic areas of operation (BCASA).

page 13

BCASA plays a key role in addressing these challenges, collaborating with public water
operators, such as Aqua Publica Europea, and engaging with organizations focused on
global justice, innovation, and technology. These partnerships extend to participation in
European and research projects, emphasizing the importance of innovation and
digitalization in enhancing the efficiency and resilience of the city’s water cycle.
The growing impacts of climate change have heightened the need for proactive measures to
secure water availability. Current forecasts indicate that Barcelona requires an additional 18
cubic hectometers of drinking water to meet future demand. At the metropolitan level,
projections are equally concerning, with significant water shortages anticipated if current
practices remain unchanged. Addressing these challenges requires transformative
approaches and sustained efforts to enhance water resource management.
To build resilience against these forecasts, Barcelona has implemented comprehensive
water management strategies, reflected in the development of recent master plans. The
Sanitation Master Plan and the Alternative Water Resources Master Plan, both introduced in
2020, form the foundation of the city's approach to sustainable water use. These plans
focus on expanding non-conventional water sources, improving wastewater treatment, and
promoting water reuse for non-potable purposes. Additionally, Barcelona has established a
detailed drought protocol to guide the city’s response during periods of water scarcity,
ensuring coordinated action across municipal and metropolitan levels.
Through these initiatives, Barcelona aims not only to address immediate water challenges
but also to create a long-term framework for sustainable water management. The city’s
commitment to innovation, collaboration, and resilience underscores its determination to
secure water resources for both its residents and the millions of visitors who rely on its
infrastructure each year.
3.1.2 Water stress context and main challenges
Barcelona is located in Catalonia, a region with two distinct river basins: the internal and
external basins. The internal basin supplies water to Barcelona, while the external basin,
encompassing only 15% of Catalonia's population, holds 80% of the region's water
resources, primarily due to the presence of major rivers and agricultural activity. This
imbalance between water availability and population distribution is a challenge common to
many regions worldwide.
Barcelona, home to 1.7 million inhabitants, experiences a Mediterranean climate
characterized by irregular rainfall patterns. While the city's annual rainfall is comparable to
that of London, the distribution is highly uneven, with intense downpours of up to 200 mm
in a single day, followed by extended dry spells lasting over 100 days. This variability
contributes to both flooding and drought, complicating water management efforts.

page 14

Figure 6. Internal basins of Catalonia (BCASA).
The city’s water resources primarily come from the Besòs and Llobregat rivers, groundwater
extraction, and water transferred from the Girona region. To diversify supply and enhance
resilience, Barcelona has invested in a desalination plant near the Llobregat wastewater
treatment plant and a reclaimed water facility. This diversification has proven crucial during
the ongoing drought that began in 2020, ensuring effective management across different
phases of the crisis.
Water governance in Catalonia involves multiple authorities (Table 2). The Catalan
government oversees water cycle management, including desalination and wastewater
treatment. The Metropolitan Area of Barcelona (AMB) is responsible for domestic and
industrial water supply, while the Barcelona City Council handles municipal water
distribution and inspection. Water tariffs are designed to promote sustainable
consumption, with lower rates for responsible usage and higher charges for excessive
consumption.
Water resource management in Catalonia aligns with the EU Water Framework Directive,
which mandates the development of hydrological plans every four years. These plans are
prepared through a participatory process involving government entities, NGOs, the scientific
community, and other stakeholders. In drought situations, all authorities collaborate to
implement action plans, balancing water availability with ecological flow requirements.

page 15

Table 2. The governance of the water sector in Barcelona (BCASA).

Catalan
government

Metropolitan area
of Barcelon

Barcelona City
Council

Hydrological
planning

High water supply

Low water supply

Surveillance and
inspection

Approval of water
tarrifs

Actions in drought
situation

Barcelona faces increasing challenges due to climate change, including more frequent
extreme weather events, prolonged dry periods, and rising temperatures. Current
projections for 2050 indicate a need for additional resources to meet urban demand (Figure
7). The city has responded by adopting short and long-term strategies, transforming each
drought into an opportunity for improvement and investment in resilient infrastructure.

page 16

Figure 7. Forecast for water needs in Barcelona Metropolitan Area (5,3 million inhabitants).
Source: https://www.pecia.cat/

3.1.3 Strategies and solutions to manage water scarcity
Long-term strategies
Key initiatives to cope with water scarcity include the Special Drought Plan of Catalonia,
which outlines mandatory actions for each drought phase, and the city's two master plans:
the Sanitation Master Plan and the Alternative Water Resources Master Plan, both finalized
in 2020. The Sanitation Master Plan focuses on mitigating urban flooding, primarily caused
by insufficient drainage capacity during torrential rains. It also addresses the reduction of
combined sewer overflows, which temporarily pollute water bodies during heavy rainfall.
The Alternative Water Resources Master Plan (PELARHAB) (Figure 8) promotes the
substitution of drinking water with alternative sources for non-potable uses, such as
irrigating public gardens, cleaning streets, and maintaining ornamental fountains (Figure 9).
This approach, supported by Barcelona’s sanitary authorities, ensures that water quality
matches the requirements of each specific use, saving significant volumes of potable water
annually.
The city has also advanced the use of reclaimed water. The Llobregat Wastewater
Treatment Plant features tertiary treatment processes, enabling the reuse of treated water
for environmental purposes, aquifer recharge to prevent saline intrusion, industrial
applications, and street cleaning. While these practices are expanding in Barcelona and
Catalonia, they remain limited across Spain due to stringent health regulations requiring
extensive testing.

page 17

Figure 8. Water Cycle Master Plans (BCASA).
To further reduce potable water consumption, Barcelona is preparing a new Grey Water
Ordinance. This regulation will mandate greywater reuse for residential and commercial
buildings consuming more than 75 to 100 cubic meters of water annually. Greywater from
showers and bathroom sinks will be treated and reused for flushing toilets, watering plants,
and cleaning common areas, potentially reducing domestic water consumption by 50%.

Figure 9. Uses of groundwater and other alternative water resources (BCASA).

page 18

Rainwater harvesting is another focus area, with initiatives promoting rainwater collection in
both public and private spaces. Inspired by Hong Kong’s direct seawater flushing system,
Barcelona is exploring a pilot project to use seawater for sanitary flushing. Although
complex and requiring a separate distribution network and adapted wastewater treatment
systems, this solution could be viable in specific districts.
Barcelona's long-standing commitment to water efficiency dates back to 1998, with the
launch of its first Alternative Water Resources Master Plan. Since then, the city has
continually expanded non-potable water use while reducing overall consumption, even as
green spaces and municipal services have increased.
Barcelona’s water management strategy also integrates Sustainable Urban Drainage
Systems (SUDS) to mitigate flooding, improve water quality, and enhance urban biodiversity.
These systems contribute to healthier public spaces, promoting bio-receptive environments
and supporting Mediterranean-adapted plant species resilient to drought conditions.

Financial adaptation and resource mobilization
Financially, water management efforts are aligned with Catalonia’s hydrological planning
cycles, ensuring that investments from the Catalan government, AMB, and municipalities
are coordinated. In times of extreme drought, collaboration between sectors - including
large water consumers such as hotels and sports facilities - plays a crucial role in promoting
efficiency and adopting new technologies.

Communication and Public Awareness
The city's success also relies on robust communication and public engagement. The “How
Barcelona Works” campaign, active for over three decades, educates citizens, schools, and
communities about water management (Figure 10). Educational initiatives include guided
tours of water facilities, such as the sewer system, to demonstrate the importance of
responsible water use and the environmental impact of improper practices like flushing wet
wipes.
Partnerships and collaborative efforts
As part of its ongoing efforts, Barcelona continues to strengthen partnerships, promote
innovation, and leverage data-driven decision-making to adapt to chronic water deficits. The
city’s comprehensive approach, combining infrastructure development, regulatory
frameworks, public engagement, and cross-sector collaboration, positions it as a model for
metropolitan water resilience in the face of climate change.

page 19

Figure 10. Example of educational and awareness program in Barcelona (BCASA).

Figure 11. Evolution of water consumption in Barcelona (BCASA).

3.1.4 Lessons-learned
These are five lessons-learned from Barcelona’s experience in water scarcity management:
1. Diversification of water resources enhances resilience: Barcelona's multi-source
water supply system, including desalination, reclaimed water, groundwater, and river
transfers, has proven essential in mitigating the impacts of prolonged droughts. This
diversified approach ensures water availability during crises and reduces dependency
on traditional water sources.

page 20

1. x
2. Integrated governance promotes efficient water management: The collaborative
governance model in Catalonia, involving the Catalan government, the Metropolitan
Area of Barcelona (AMB), and the Barcelona City Council, facilitates coordinated
decision-making. Clear roles and shared responsibilities among authorities improve
response efficiency during drought conditions.
3. Alternative water resources reduce potable water demand: Initiatives like the
Alternative Water Resources Master Plan and the upcoming Grey Water Ordinance
demonstrate how reclaimed water, rainwater harvesting, and greywater reuse can
significantly reduce potable water consumption. These practices not only conserve
drinking water but also support sustainable urban development.
4. Public engagement and awareness drive behavioral change: The long-standing
"How Barcelona Works" campaign highlights the importance of public education in
promoting responsible water use. By engaging citizens, schools, and businesses,
Barcelona has fostered a culture of water conservation, ensuring widespread support
for water-saving initiatives.
5. Data-driven planning and innovation ensure long-term sustainability: Barcelona’s
continuous investment in scientific modeling, monitoring systems, and smart
technologies allows for adaptive management in response to climate change. This
evidence-based approach ensures that water management strategies remain effective
as environmental conditions evolve.

3.2 City of Cape Town, South Africa
3.2.1 Comprehensive overview of City of Cape Town Municipality
Cape Town, located in the Western Cape Province of South Africa, has a population of
approximately 4.7 million people, according to the latest census (Figure 12). The local
government, through the City of Cape Town municipality, is responsible for providing
residents, businesses, and visitors with reliable access to clean, safe water while ensuring
effective wastewater treatment and environmental management. This comprehensive
mandate includes overseeing water catchments, managing water storage, and ensuring the
safe disposal of treated wastewater back into the environment.
The city's water infrastructure is extensive, consisting of 14 dams, 12 water treatment
works, 622 pump stations, 180 reservoirs, and 23 wastewater treatment facilities. To
maintain service delivery across the metropolitan area, Cape Town manages more than
20,000 kilometers of pipeline and responds to approximately 1,000 service requests daily.
These requests often involve addressing pipe bursts, water leaks, and blockages, reflecting
the scale and complexity of the city’s water management operations.

page 21

Figure 12. Location of Cape Town and view of the city

13

Cape Town, located in the Western Cape Province of South Africa, has a population of
approximately 4.7 million people, according to the latest census (Figure 12). The local
government, through the City of Cape Town municipality, is responsible for providing
residents, businesses, and visitors with reliable access to clean, safe water while ensuring
effective wastewater treatment and environmental management. This comprehensive
mandate includes overseeing water catchments, managing water storage, and ensuring the
safe disposal of treated wastewater back into the environment.
The city's water infrastructure is extensive, consisting of 14 dams, 12 water treatment
works, 622 pump stations, 180 reservoirs, and 23 wastewater treatment facilities. To
maintain service delivery across the metropolitan area, Cape Town manages more than
20,000 kilometers of pipeline and responds to approximately 1,000 service requests daily.
These requests often involve addressing pipe bursts, water leaks, and blockages, reflecting
the scale and complexity of the city’s water management operations.
The severe drought experienced in recent years highlighted the limitations of relying solely
on surface water, especially in the context of climate change and rapid population growth.
Since 2011, Cape Town's population has increased by nearly 30%, driven by both internal
1. x
migration
from other parts of South Africa and international migration from across the
2. x
continent.
This surge in population, coupled with changing long-term weather patterns, has
3. x
4. x
placed
significant strain on the city's water infrastructure, underscoring the need for
5. Luo, T., R. Young, P. Reig. 2015. “Aqueduct Projected Water Stress Country Rankings.” Technical Note. Washington,
adaptive
strategies
to ensure
long-term
water security.
D.C.: World
Resources Institute.
Available
online at: www.wri.org/publication/aqueduct-projected-water-stresscountry-rankings
6. https://wad.jrc.ec.europa.eu/waterstress
In7. https://wad.jrc.ec.europa.eu/waterstress
response to these challenges, Cape Town introduced a new water strategy aimed
augmenting
the city's water supply by 300 million liters per day from diversified sources
8. x
9.
x
2030.
10. x
11. x
12. x
13. https://en.wikipedia.org/wiki/Cape_Town

at
by

page 22

2030. This strategy includes several key initiatives, such as clearing invasive alien vegetation,
which consumes significant amounts of water. Groundwater extraction from aquifers has
also been prioritized, providing an alternative to surface water sources. Additionally, water
reuse has emerged as a significant focus area. While previously unexplored in Cape Town,
water reuse now plays a central role in the city's resilience strategy. This initiative has
required extensive public communication efforts to build acceptance for reintroducing
treated water into the potable water system.
Infrastructure maintenance remains a core component of the city's water strategy, ensuring
the existing network operates efficiently while minimizing water losses. In addition to these
measures, Cape Town is also exploring long-term solutions such as desalination. Although
costly, desalination remains a viable option within the city's broader water resilience
framework, reflecting a multi-faceted approach to securing the city's water future in the face
of evolving environmental and demographic challenges.
3.2.2 Water stress context and main challenges
Cape Town, the largest city in South Africa's Western Cape, faced an unprecedented water
crisis during the 2017–2018 drought, the worst in the city’s recorded history. With rainfall
significantly below average, dam levels dropped to just 20%, and engineers warned that the
last 10% of the water was inaccessible. This dire situation prompted the city to adopt
emergency measures while developing long-term resilience strategies. The lessons learned
from this crisis have shaped Cape Town's comprehensive water strategy, ensuring a more
sustainable and adaptive water management system.
3.2.3 Strategies and solutions to manage water scarcity
Short-term strategies
During the height of the crisis, Cape Town implemented several short-term measures to
reduce water consumption and prevent the city from reaching "Day Zero," the point when
municipal water supplies would be cut off and residents would need to collect water
manually from designated points. Leak detection and rapid repairs became a top priority, as
the city's extensive pipe network posed a significant risk of water loss. To control excessive
consumption, the city introduced water management devices, which limited household
usage once a threshold was reached. Although controversial at the time, these devices
played a crucial role in conserving the available water supply. Additionally, invasive alien
vegetation, known for consuming large quantities of water, was systematically cleared from
catchment areas to increase runoff into dams.

page 23

An extensive communication campaign was launched to promote behavioral change among
residents. The campaign used visual materials, social media, and public outreach to
illustrate water-saving practices, such as taking shorter showers, limiting toilet flushing, and
reducing outdoor water use. Public awareness efforts emphasized that every drop counted,
encouraging citizens to adhere to the strict daily limit of 50 liters per person. Citizens and
communities were mobilized through a ‘3Cs’ partnering campaign - ‘Connect, Communicate,
Collaborate.’ Water rationing was enforced across the city, and emergency supplies were
delivered to the most affected areas, ensuring that essential needs were met.

Long-term strategies
Recognizing the vulnerability of relying solely on surface water, Cape Town developed a
comprehensive water strategy to build long-term resilience. This strategy was founded on
five core commitments: ensuring safe and equitable access to water, promoting efficient
use, diversifying supply sources, sharing regional water resources, and becoming a watersensitive city. The strategy emphasized that future water security required a departure from
historical reliance on rainfall and surface water, shifting towards more diversified and
adaptive solutions.
To reduce dependence on rainfall, Cape Town is expanding its water supply through
groundwater extraction, and water reuse. The city developed three major aquifers to tap
into groundwater reserves, providing a reliable buffer during droughts.. Water reuse also
became a critical component of the strategy, with treated effluent reintroduced into the
potable water system through an initial pilot project. Despite initial public resistance,
extensive communication campaigns helped build trust in the safety and quality of
reclaimed water. Rainwater harvesting initiatives further supported resilience, encouraging
residents and businesses to install collection systems for non-potable uses, such as
irrigation and cleaning.
Financial adaptation and resource mobilization
Expanding Cape Town's water infrastructure required significant financial investment. The
city allocated 5.7 billion rand (approximately USD 320 million) from its capital budget to
deliver an additional 300 million liters of water per day through groundwater schemes, and
water reuse projects. Water tariffs were adjusted to support infrastructure development,
although the increases faced resistance from middle-class residents, who viewed the rising
costs as burdensome. To bridge funding gaps, the city pursued public-private partnerships
and secured external financing from development banks and donor organizations.

page 24

The drought also underscored the importance of regional cooperation and multi-sectoral
partnerships. Cape Town adopted a Regional Water System Partnering Approach, involving
five neighboring municipalities, agricultural stakeholders, the national Department of Water
and Sanitation, brought together by an independent intermediary called the Western Cape
Economic Development Partnership (EDP). This non-statutory platform fostered dialogue
among stakeholders, promoting collaborative decision-making around water allocations,
assurance of water supply, climate change mitigation strategies, and catchment
management. By encouraging stakeholders to collaborate beyond institutional boundaries
and mandates, and by focusing on building a common agenda for joint action amongst
diverse stakeholders, the initiative strengthened regional resilience and accountability.
Communication and Public Awareness
Effective communication played a pivotal role in Cape Town's water-saving efforts. The city
tailored messaging to different communities, recognizing disparities in access to
information and water infrastructure. Wealthier residents, who had access to digital
platforms, were targeted through social media campaigns, billboards, and news outlets. In
contrast, poorer communities, where residents often relied on communal standpipes,
received information through radio broadcasts, public meetings, and direct community
engagement. A water dashboard provided daily updates on dam levels, consumption rates,
and conservation targets, fostering community accountability.

page 25

Figure 13. Campaign informing the population on Day Zero.

The city’s “Save Like a Local” campaign further reinforced water-saving behaviors. Partnering
with the hospitality industry, the city ensured that tourists were informed about the drought
and encouraged to adopt responsible practices during their stay (Figure 14). Upon arrival at
Cape Town International Airport, visitors encountered signage promoting water
conservation, while hotels and Airbnb hosts provided informational packages. As the crisis
intensified, the campaign took on a starker tone, warning residents about the impending
arrival of Day Zero (Figure 13). Posters marked future water collection points, emphasizing
the reality of potential water shortages and motivating further behaviour change and
conservation efforts.

Figure 14. Examples of the communication campaign “Save Like a Local”.

page 26

The success of Cape Town's response can be attributed to the integration of technical,
financial, and social strategies. By diversifying water sources, promoting behavioral change,
fostering regional cooperation, and securing sustainable financing, the city has built
resilience against future droughts. The crisis served as a catalyst for innovation,
transforming Cape Town’s approach to water management and establishing a model for
other cities facing similar challenges.
Partnerships and collaborative efforts
Cape Town is part of the Western Cape Water Supply System (WCWSS), which it shares with
5 other municipalities, agriculture and the national Department of Water and Sanitation.
Cape Town participates in a Water Users Platform convened by an independent
collaborative intermediary organisation that helps participants develop a common agenda
for joint action around potentially divisive issues such as waters allocations, assurance of
supply, pricing and tariffs, mitigating impacts of climate change, clearing of invasive alien
plants, catchment management, water quality, and future system augmentation (Figure 15).

Figure 15. Meeting of the WCWSS Water Users Platform.
Ultimately, Cape Town’s experience highlighted several key lessons. First, diversification of
water sources is essential to reduce reliance on rainfall and surface water. Second, effective
communication, and building relationships of trust between public authorities and citizens,
is crucial for promoting behavioral change and fostering community participation. Third,
regional cooperation strengthens resilience by aligning stakeholders around shared water
resources. Fourth, sustainable financing requires balancing affordability with the need for
infrastructure investment. Finally, a crisis can drive innovation, prompting cities to adopt
adaptive strategies that ensure long-term water security.

page 27

Figure 16. Interfaith group meeting.

3.2.4 Key lessons
These are five lessons-learned from Cape Town’s experience in water scarcity management:
1. Importance of diversifying water sources: Heavy reliance on surface water proved
unsustainable when dam levels fell to 20%. Investing in groundwater extraction and
water reuse systems created a more resilient supply, demonstrating the need for
multiple water sources to withstand climate variability.
2. Effective communication in promoting behavioral change: Public awareness
campaigns, including the "Save Like a Local" initiative, encouraged water-saving
practices among residents and tourists. Clear, consistent messaging across diverse
platforms proved crucial for community-wide action during the crisis.
3. Regional cooperation strengthens resilience: Cape Town partnered with five
neighboring municipalities, agricultural users, the national Department of Water and
Sanitation, and facilitators to manage shared water resources. This collaborative
approach showed that effective water governance extends beyond municipal
boundaries.
4. Need for sustainable financing to support water infrastructure development: Cape
Town invested 5.7 billion rand (USD 320 million) in groundwater and water reuse
projects, supported by external financing and tariff adjustments. Despite resistance to
higher tariffs, the strategy balanced affordability with infrastructure resilience.
5. Emergencies can drive innovation: Cape Town’s drought response led to adaptive
measures, such as advanced leak detection and sustainable urban planning. This
experience highlighted how water crises can inspire transformative solutions for longterm sustainability.

page 28

3.3 City of Douala, Cameroon
3.3.1 Comprehensive overview of Douala City Council
Douala, the largest city in Cameroon and Central Africa, serves as a vital economic hub and
gateway for trade and commerce in the region. Strategically located along the Wouri River,
the city is home to an estimated five million people as of 2023 (Figure 17). The Douala City
Council, known in French as "Communauté Urbaine de Douala," plays a pivotal role in
managing the city's development and ensuring the well-being of its residents. Its mandate
includes urban planning, water supply, waste management, and public transportation.
Efforts are underway to digitalize urban planning processes, promoting efficient land use
and streamlined administrative operations. The Council also focuses on enhancing public
services and infrastructure to improve living conditions, including access to clean water,
mobility, and social facilities.

Figure 17. Location of Douala. Water supply network and infrastructures.
Douala's significance extends beyond Cameroon, serving as a key access point for
neighboring countries such as Chad, the Central African Republic, Gabon, and Equatorial
Guinea. This regional importance underscores the need for robust infrastructure and
efficient resource management. The city is governed by an elected mayor, who serves a fiveyear term, supported by a dedicated staff and technical departments responsible for
overseeing various aspects of municipal management, including water services.
Despite the city's strategic location and abundant rainfall, Douala faces a paradoxical
challenge: many residents lack access to reliable drinking water. The primary water supplier,
the Cameroon Water Utilities Corporation (CAMWATER), is responsible for producing and
distributing potable water.

page 29

distributing potable water. However, rapid population growth has outpaced the existing
infrastructure's capacity. The city's daily water demand is estimated at 770,000 cubic
meters, yet CAMWATER can only meet around 60% of this requirement. As a result, the
Douala City Council is exploring alternative solutions to bridge the gap and improve water
coverage across the metropolitan area.
Inadequate infrastructure remains one of the most pressing challenges. The aging water
supply network is often insufficient to meet the needs of the expanding population, leading
to intermittent supply and, in some neighborhoods, a complete lack of access to clean
water. Compounding this issue is the problem of water quality. Industrial activities and
inadequate sanitation facilities contribute to the contamination of water sources, posing
significant risks to public health. Many residents, particularly in underserved areas, rely on
untreated water, increasing their vulnerability to waterborne diseases.
To address these challenges, the Douala City Council continues to work on enhancing
infrastructure, improving water quality, and expanding access to safe drinking water.
Collaborative efforts with national agencies, international partners, and private
stakeholders are essential to ensuring that Douala's residents can enjoy sustainable and
equitable water services, ultimately supporting the city’s vision of becoming a leading
economic and cultural center in Central Africa.
3.3.2 Water stress context and main challenges
Douala, Cameroon’s largest city and economic hub, faces significant water stress due to
rapid population growth, climate change, and limited water infrastructure. Surrounded by
rivers and the Atlantic Ocean, the city’s geographical position does not translate into water
security, as groundwater contamination, irregular rainfall patterns, and insufficient supply
systems create ongoing challenges. From a population of 1.5 million in 1995, Douala has
grown to nearly 4 million residents in 2023, requiring approximately 400,000 cubic meters
of drinking water daily to meet basic needs.
Like many African cities, Douala struggles with the increasing gap between water demand
and supply. The city experiences six months of heavy rainfall, with annual precipitation
reaching up to 4,000 millimeters, followed by prolonged dry periods. Water contamination
from industrial and domestic pollution further exacerbates the situation. Groundwater,
although abundant, is often compromised due to Douala’s low elevation, making efficient
water management challenging.

page 30

3.3.3 Strategies and solutions to manage water scarcity
Short-term strategies
To address immediate water shortages, the government implements water rationing,
prioritizing essential consumption. Public awareness campaigns, broadcasted through
television and other media platforms, educate residents on water conservation practices.
Emergency water supplies are provided to the most affected areas, while ongoing efforts
focus on repairing leaks to reduce water losses caused by aging infrastructure.
The Cameroon Water Utility Corporation (CAMWATER), the state-owned water supplier, is
primarily responsible for Douala's water distribution. However, limited supply capacity has
led many residents to rely on private water vendors, boreholes, and wells. This fragmented
water access highlights the need for more resilient infrastructure and diversified water
sources.
Long-term strategies and infrastructure development
Douala's long-term water management strategy includes the adoption of water-efficient
technologies, rainwater harvesting, and expanded water treatment facilities. Efforts are
underway to promote efficient irrigation systems, ensuring that available resources are
used optimally. The city council is also promoting rainwater collection technologies for
household and municipal reuse, aiming to reduce dependence on conventional water
sources.
Improving water treatment capacity remains a priority, with plans to enhance water quality
and expand supply infrastructure. However, the challenge lies in the fact that CAMWATER
remains the sole official supplier in Cameroon, struggling to meet the rising demands of the
urban population. Sustainable urban planning initiatives, including the development of
green spaces and flood-resilient infrastructure, further support Douala’s long-term water
resilience goals.
Financial adaptation and resource mobilization
Addressing water scarcity in Douala requires significant financial investment. The city relies
heavily on central government funding and international grants to implement water
projects. Government-backed loans, including ongoing efforts to secure €65 million from
international financial institutions, are crucial for infrastructure development. However, the
city council's capacity to independently finance large-scale water projects remains limited.
Given the scale of the challenge, Douala collaborates with international partners, including
development banks and donor organizations, to access capital for critical water projects.
The city’s reliance on central government financing underscores the need for diversified
funding sources, including private sector participation and international support.

page 31

Figure 18. Wastewater treatment plant facilities in Douala.
Partnerships and collaborative efforts
Effective water management in Douala involves a multi-stakeholder approach. The city
collaborates with government agencies, water utilities, research institutions, and
universities to advance water security initiatives. Partnerships with academic institutions
support research on sustainable water solutions, while engagement with development
organizations facilitates access to technical expertise and funding opportunities.
CAMWATER remains the primary entity responsible for water distribution, while the Douala
City Council focuses on complementary initiatives, such as borehole drilling, rainwater
harvesting, and water tanker services for underserved communities. This collaborative
framework, though limited by institutional constraints, remains essential for advancing
water resilience in the city.
Communication and Public Awareness
Raising public awareness about water conservation is a key component of Douala's water
management strategy. The city implements communication campaigns through public
meetings, media outreach, social media platforms, and direct community engagement.
These initiatives aim to promote responsible water use and educate residents on practical
conservation measures.
The City Council emphasizes the importance of behavioral change, encouraging households
and businesses to adopt water-saving practices. However, the effectiveness of these
campaigns depends on the availability of reliable water supplies and the implementation of
complementary infrastructure improvements.

page 32

Figure 19. Cover of the National Strategy for Promoting Access to Drinking Water, Hygiene, and
Sanitation in Schools in Cameroon.
Douala’s experience underscores the complex interplay between population growth, climate
change, and water infrastructure challenges. While the city faces no significant shortage of
water resources, the quality, accessibility, and distribution of water remain critical issues.
Efforts to address these challenges rely on government-led investments, international
partnerships, and community engagement.
Moving forward, strengthening water governance, diversifying supply sources, and investing
in resilient infrastructure will be essential for ensuring sustainable water access in Douala.
The city’s approach highlights the importance of collaborative action, adaptive strategies,
and continuous investment to build urban water resilience in the face of evolving
environmental and demographic pressures.

3.3.4 Key lessons
These are five lessons-learned from Douala’s experience in water scarcity management:
1. Diversification of water sources is essential for resilience: Douala’s reliance on a
single official water supplier has created challenges in meeting the city's growing
demand. The promotion of rainwater harvesting, boreholes, and private water vendors
highlights the need for diversified supply sources to enhance water security and reduce
dependence on centralized systems.

1. Diversification of water sources is essential for resilience: Douala’s reliance on a
single official water supplier has created challenges in meeting the city's growing
page 33
demand. The promotion of rainwater harvesting, boreholes, and private water vendors
highlights the need for diversified supply sources to enhance water security and reduce
dependence on centralized systems.
2. Infrastructure investment must keep pace with urban growth: Rapid population
growth has outstripped the capacity of existing water infrastructure. To ensure
sustainable water access, long-term planning and investment in water treatment
facilities, expanded distribution networks, and modernized infrastructure are necessary
to accommodate future demand.
3. Public awareness and behavioral change strengthen conservation efforts:
Communication campaigns through media, public meetings, and direct engagement
have been crucial in promoting responsible water use. Educating residents on
conservation practices fosters long-term water-saving behaviors, reducing overall
demand and improving efficiency in water consumption.
4. Financial adaptation requires international and private sector support: Given the
financial limitations of local governments, Douala’s reliance on central government
funding and international grants demonstrates the importance of accessing diverse
financial sources. Strengthening partnerships with international donors, development
banks, and private investors is crucial for scaling water infrastructure projects.
5. Collaboration across government, institutions, and communities is key: Effective
water management in Douala depends on coordination among government agencies,
water utilities, research institutions, and local communities. A multi-stakeholder
approach ensures that policies, technological advancements, and investment priorities
align to address water scarcity challenges effectively.

3.4 City of Montevideo, Uruguay
3.4.1 Comprehensive overview of the municipal institution
Montevideo, the capital of Uruguay, stands as one of Latin America's most stable and
prosperous cities, characterized by its high-income status, relatively low unemployment
rates, and balanced climate (Figure 20). The city’s relationship with water is deeply rooted in
its origins as a port for Latin America. Water not only serves as a resource but also as a
public space, fostering recreation, tourism, and community interaction. This access to water
is viewed as a democratic right, reinforcing the importance of maintaining high water quality
standards for both rivers and coastal areas. The proximity to water also exposes
Montevideo to climate change risks, including rising sea levels that threaten to submerge
parts of the city within the next few decades. This uncertainty presents a significant
challenge for urban planning and environmental management.
Water management extends beyond Montevideo’s borders, as river basins flow through
both the city and surrounding metropolitan areas. Collaboration with neighboring
municipalities is essential to address shared challenges, including urban flooding. Heavy
rains frequently overwhelm the drainage system, causing localized flooding and
infrastructure strain. These vulnerabilities became particularly evident in 2023, when
Montevideo

page 34

Montevideo faced its first major water crisis. For the first time in recent history, the
metropolitan area confronted the possibility of losing access to running water, an
unprecedented situation compounded by the year’s most severe flooding events in
Uruguay’s history.

Figure 20. Location of Montevideo and map of the city.

The Montevideo City Council, established in 1920, governs the city through an executive and
administrative structure responsible for urban management. Under the leadership of the
current Mayor, the Council has prioritized environmental sustainability and resilience. The
Environmental Department oversees critical functions, including sewage and rainwater
drainage, urban cleaning, and environmental management. This multifaceted approach
allows the city to address water bodies and resources from various perspectives, though the
council does not manage the provision of potable water, which falls under national
jurisdiction.
3.4.2 Water stress context and main challenges
Montevideo, the capital city of Uruguay, faced an unprecedented water crisis in 2023,
highlighting significant vulnerabilities in the region’s water supply system. Although the
Montevideo City Council is not responsible for the provision of drinking water, it oversees
the city’s sewage and drainage systems. In collaboration with the Inter-American
Development Bank (IDB), efforts have been ongoing to achieve universal sewage and
drainage coverage. However, the recent water scarcity, coupled with severe flooding,
exposed critical gaps in the city’s water management strategies.

page 35

Figure 21. Effects of drought in Paso Severino dam infrastructure.
Despite Uruguay being known for its abundant water resources, including rivers, creeks,
and underground reserves, the country faced an unexpected water stress event. The El
Niño/Southern Oscillation (ENSO) affects Uruguay periodically with increases in
precipitation in El Niño years and shortage in La Niña years (Figure 22). This latest 3-year
event has resulted in the worst drought ever registered. While most regions received
consistent precipitation, the Santa Lucía River basin, the primary source of drinking water
for Montevideo and the metropolitan area, experienced an alarming drought. This basin
supplies water to nearly half of Uruguay's population, and for the first time in three
decades, the Paso Severino dam, the main reservoir, ran dry (Figure 21).

Figure 22. Oceanic Niño Index (ONI) for Uruguay.

page 36

Montevideo's relationship with water is deeply intertwined with its urban and coastal
identity. The city is known for its urban creeks, public beaches, and coastal recreational
spaces, accessible to all residents and visitors. Additionally, Montevideo's rural hinterlands
contribute to local food production, supplying fruits and vegetables to the city and
surrounding areas. However, the water crisis severely disrupted these activities, affecting
both domestic use and agricultural production. Compounding the crisis, extreme weather
events, including strong winds and storms, led to flooding, complicating drainage efforts in
low-lying coastal neighborhoods.

3.4.3 Strategies and solutions to manage water scarcity
The collapse of the metropolitan water supply system forced authorities to take emergency
measures. The Paso Severino dam, located 40 kilometers from the capital, traditionally
provided sufficient drinking water. However, as the reservoir dried up (Figure 21),
authorities were compelled to source water from the Río de la Plata, an estuarine system
with brackish water (Figure 23). The Santa Lucía water treatment plant, designed for
freshwater processing, lacked the capacity to desalinate, resulting in increased levels of
sodium and chlorine in the municipal water supply. This deterioration in water quality led to
widespread public rejection, as the population was unaccustomed to drinking water with
elevated salinity levels.

Figure 23. Mixture of water with different composition.
To address the crisis, the Ministry of Health temporarily revised acceptable thresholds for
sodium and chlorine in tap water. While the water remained suitable for sanitation and
bathing, it was deemed unsuitable for drinking, prompting the distribution of bottled water
to vulnerable populations. The City Council coordinated the delivery of bottled water to
health centers,

page 37

health centers, retirement homes, schools, and hospitals, ensuring access to safe drinking
water. This response, however, presented logistical challenges, including the collection and
disposal of plastic waste generated by bottled water distribution.
Communication and transparency played a critical role in managing public anxiety during
the crisis. The population, unaccustomed to water scarcity, demanded real-time updates on
water quality and safety. Health authorities, engineers, and municipal officials provided
daily reports through multiple channels, including media briefings and official websites. Risk
communication efforts clarified the health implications of consuming water with elevated
sodium and chlorine levels, helping residents make informed decisions about whether to
purchase bottled water or rely on tap water for non-consumptive uses.

Figure 24. Cover of the first plan of Integrated Risk Management of Montevideo.
The crisis exposed significant gaps in Montevideo’s water management plans. Despite
having contingency frameworks in place, authorities realized that existing strategies were
insufficient to handle such an extreme event. This recognition prompted the city to revise its
Climate Action Plan (Figure 25), incorporating new strategic lines focused on drinking water
resilience. Prior to the crisis, water security had not been prioritized within the city's
broader climate adaptation strategies. The revised plan now emphasizes sustainable water
management, risk mitigation, and improved infrastructure resilience.
Moving forward, Montevideo faces significant challenges in achieving full coverage for
sewage, drainage, and drinking water services. Investment in infrastructure expansion is
essential, but equally important is the maintenance of existing systems to ensure long-term
functionality. Reducing water leaks, enhancing drainage capacity, and minimizing flood risks
remain critical priorities. The city has acknowledged that resilience requires not only
expanding networks but also ensuring their continued efficiency and adaptability in the face
of climate variability.

page 38

of climate variability. The 2023 water crisis served as a wake-up call, underscoring the need
for proactive planning, robust infrastructure, and a cultural shift toward responsible water
consumption in a region historically perceived as water-abundant.

Figure 25. Cover of the Montevideo Climate Action Plan.

3.4.4 Key lessons
These are five lessons-learned from Montevideo’s experience in water scarcity
management:
1. Diversifying water sources: Heavy reliance on the Santa Lucía River basin and the Paso
Severino dam proved unsustainable when the reservoir dried up. The emergency use of
brackish water from the Río de la Plata highlighted the need for alternative sources like
groundwater, rainwater harvesting, and desalination, alongside adaptable treatment
infrastructure.
2. Necessity of robust contingency planning: Existing risk management frameworks fell
short during the crisis, exposing gaps in maintaining water quality and distributing
bottled water. This led to a revision of Montevideo's Climate Action Plan, integrating
water resilience as a core objective for future adaptation efforts.for future climate
adaptation efforts.
3. Critical role of effective communication and transparency: As water quality
declined, residents demanded real-time updates. Daily briefings and media
announcements, combined with clear health advisories, ensured informed decisionmaking while strengthening public trust in the authorities’ response.

page 39
1. mm
2. m
3.
4. Importance of addressing infrastructure vulnerabilities: Water leaks, inefficient
drainage, and inadequate flood protection worsened the crisis, underscoring the need
for continuous maintenance and investment in wastewater management and flood
control systems.
5. Need for a cultural shift toward responsible water consumption: The crisis
challenged long-standing habits, prompting awareness campaigns and educational
initiatives to emphasize water’s value as a finite resource. The experience highlighted
that true resilience depends on both infrastructure and proactive societal behavior.

3.5 City of San Francisco, USA
3.5.1 Comprehensive overview of San Francisco Public Utilities Commission
The San Francisco Public Utilities Commission (SFPUC) is a municipal public agency
responsible for delivering three essential utility services: water, power, and sanitation
(Figure 27). The agency provides water services to 2.7 million residents across the San
Francisco Bay Area (Figure 26), generates both hydropower and solar power through its
energy division, and operates a combined sewer system that collects and treats both
stormwater and sanitary waste before safely discharging it into the San Francisco Bay and
Pacific Ocean.

Figure 26. Location of San Francisco and view of the city.

page 40

Figure 27. Public services provided by SFPUC.
With a legacy of delivering high-quality, reliable services for over a century, SFPUC now faces
growing challenges that threaten its ability to maintain service reliability. California’s
increasing vulnerability to drought remains one of the most pressing concerns, as periods
of water scarcity become more frequent, severe, and closely spaced. Wildfires, often
exacerbated by drought conditions, further strain the region's resources. Additionally, aging
infrastructure, with some water pipes dating back to the late 1800s, requires extensive
upgrades to meet modern standards. The city’s ongoing urban development, the need to
maintain ecological flows in streams and rivers, and the threat of urban flooding add further
complexity to the utility’s responsibilities.
To address these challenges, SFPUC has adopted a forward-looking approach to water
management, shifting from a traditional linear model to a circular economy framework. This
"One Water" strategy emphasizes integrated planning across water, energy, and wastewater
systems, ensuring that projects deliver multiple benefits for both customers and the
environment. Embracing this holistic approach allows the utility to maximize resource
efficiency while enhancing resilience in the face of climate change.
A critical component of this transformation has been the agency’s investment in
infrastructure improvements. SFPUC is nearing completion of a $4.6 billion capital
improvement program aimed at upgrading the water system to guarantee reliable service
delivery. In addition to modernizing existing infrastructure, the utility has diversified its
water supply portfolio, recognizing that surface water alone limits future adaptability to
climate uncertainties. New initiatives include groundwater development, expanded use of
recycled water, and the implementation of onsite water recycling systems in new buildings
and

page 41

and districts across San Francisco. The agency is also exploring the potential of purified
water—treating wastewater to drinking water standards—and investigating the feasibility of
desalination as an alternative supply source.
Drought preparedness remains a top priority for SFPUC. Extensive planning efforts have
been dedicated to developing drought management strategies that ensure water availability
during prolonged dry periods. This comprehensive approach includes supply monitoring,
demand management, and collaborative planning with regional partners. These efforts not
only protect the city’s water resources but also strengthen overall system resilience against
future climate uncertainties.
Community engagement plays a vital role in SFPUC’s strategy. Educating residents,
businesses, and stakeholders about the evolving needs of the water system fosters public
understanding and support for necessary changes. Through outreach initiatives and
participatory programs, the utility encourages sustainable water practices while ensuring
that communities remain informed and involved in decision-making processes.
Partnerships and collaborative efforts
SFPUC’s commitment to innovation, resilience, and community collaboration reflects its
determination to continue providing high-quality water, power, and sanitation services. By
embracing integrated solutions and future-oriented planning, the agency is positioning itself
to navigate the complexities of the 21st century while safeguarding essential resources for
generations to come.
3.5.2 Water stress context and main challenges
SFPUC’s water system relies heavily on snowmelt from the Sierra Nevada Mountains, with
85% of the supply stored in the Hetch Hetchy Reservoir within Yosemite National Park
(Figure 28). This high-quality water travels approximately 265 kilometers to San Francisco by
gravity, generating hydropower along the way. Additionally, rainfall collected in local
reservoirs near the city is blended with Sierra Nevada water to meet customer needs. This
pristine water supply historically supported San Francisco’s development, including its role
in the early days of Silicon Valley's chip manufacturing, which required exceptionally pure
water.

page 42

Figure 28. Hetch Hetchy Regional Water System, services of SFPUC.
Despite this reliable water source, San Francisco faces numerous challenges in maintaining
its utility services, including recurring droughts (Figure 29), wildfires, aging infrastructure,
urban growth, and regulatory requirements for environmental water releases. Some of the
city's water pipes date back to the late 1800s, highlighting the need for continual
infrastructure renewal. Additionally, San Francisco’s combined sewer system, which collects
both stormwater and wastewater in the same pipes, contributes to frequent urban flooding
during heavy rainfall. Given these challenges, the city has adopted a proactive approach to
water management, treating drought preparedness as an ongoing priority rather than an
intermittent crisis.

Figure 29. Drought in California.

page 43

3.5.3 Strategies and solutions to manage water scarcity
To maintain reliable water delivery, SFPUC operates under the assumption of an "eight-anda-half-year design drought," planning its operations as though seven and a half years of
drought will be followed by only one year of adequate rainfall. This conservative approach
ensures that the city always maintains a three-year water supply within its system. Water
shortage allocation plans are updated annually to account for evolving conditions, ensuring
that both San Francisco and its wholesale customers outside the city are prepared to
manage consumption during dry periods. SFPUC also implements voluntary and mandatory
water-use reduction programs, depending on the severity of the drought.

Long-term strategies and infrastructure development
Long-term resilience strategies focus on infrastructure upgrades and supply diversification.
The city is nearing completion of a $4.6 billion capital improvement program to modernize
its water and wastewater systems, partially funded through green bonds, which offer
favorable interest rates while promoting climate-resilient projects. Though SFPUC secures
some grants and low-interest loans, the majority of funding comes from ratepayers. To
balance affordability with sustainability, the agency has capped rate increases and provides
financial assistance to lower-income households for water and sewer bills.
Diversifying the water supply portfolio has been another critical focus (Figure 30).
Historically reliant on surface water, San Francisco now promotes water efficiency and
conservation, resulting in residential per capita consumption of 159 liters per person per
day—half the statewide average and one of the lowest in the United States. This
achievement reflects over 30 years of investment in water-saving initiatives, including
rebates for low-flow fixtures, technical assistance programs, and leak detection efforts. The
city has reduced water loss to less than 8% across its system.
In addition to promoting efficiency, SFPUC has expanded its water sources. Groundwater
pumping began in 2017, blending local groundwater with surface water supplies. Recycled
water is now used for irrigation and other non-potable purposes, while an innovative onsite
water reuse program mandates that all new buildings over 9,000 square meters install
water treatment systems for toilet flushing, irrigation, and laundry. This initiative
exemplifies the city’s commitment to public-private partnerships for sustainable water
management.
Looking ahead, San Francisco is exploring purified water production, which involves treating
wastewater to drinking-water standards. Recent California regulations governing this
process are stringent, ensuring public health protection but also increasing costs and
operational

page 44

operational complexity. Community acceptance remains a significant challenge, requiring
robust outreach and education efforts. SFPUC is also investigating desalination as an
additional supply option, though concerns about brine disposal and energy consumption
complicate its feasibility. Water transfers from agricultural areas to urban centers are
another potential solution, though such arrangements involve complex institutional
negotiations.

Figure 30. SFPCU’s diversification of water sources.
Financial adaptation and resource mobilization
To maintain financial stability during droughts, SFPUC introduced a drought surcharge,
adding 5% to customer bills while encouraging water conservation. This approach ensures
that reduced consumption does not undermine the utility's financial health, though it
requires careful communication to gain public acceptance. The city also provides rebates
and financial assistance to support the adoption of water-efficient appliances and fixtures,
ensuring that conservation efforts remain equitable across all communities.
Communication and Public Awareness
In terms of communication, SFPUC conducts extensive public awareness campaigns (Figure
31), providing real-time information through multiple channels. Outreach includes in-home
consultations, business assessments, and educational materials tailored to diverse
audiences. During drought emergencies, the focus initially targets outdoor irrigation, as it
represents the least essential use of water. Restrictions escalate as conditions worsen,
ensuring that the most critical water needs are prioritized.
San Francisco’s holistic approach to water management—combining supply diversification,
infrastructure investment, financial planning, and public engagement—demonstrates how
urban

page 45

urban utilities can adapt to the growing challenges of climate change and water scarcity.
Through continuous innovation and collaborative partnerships, the city strives to secure a
resilient and sustainable water future for all its residents.

Figure 31. Examples of public awareness campaigns and public assistance.

3.5.4 Key lessons
These are five lessons-learned from San Francisco’s experience in water scarcity
management:
1. Long-term drought planning is essential: The city operates under the assumption of
an "eight-and-a-half-year design drought," ensuring a three-year water supply regardless
of rainfall. Regular evaluations and water shortage allocation plans ensure adaptive
management and equitable distribution.
2. Diversifying water sources enhances resilience: San Francisco expanded its supply
through groundwater pumping, recycled water for non-potable uses, and onsite water
reuse in large buildings. The city is also exploring purified water production,
desalination, and agricultural water transfers to reduce dependence on surface water.
3. Infrastructure investment strengthens water security: A $4.6 billion capital
improvement program has modernized the water system, reducing water loss to less
than 8% and lowering residential consumption to 159 liters per person per day, half the
statewide average.
4. Financial planning ensures stability: SFPUC introduced a 5% drought surcharge to
sustain utility operations during droughts, while affordability programs support lowincome households. This approach aligns economic incentives with conservation goals.
5. Effective communication drives public engagement: Extensive outreach campaigns
provide real-time information and promote water-saving practices, ensuring community
buy-in and fostering a culture of conservation.

page 46

3.6 The experience of European water
operators addressing water scarcity - Aqua
Publica Europea (APE)
14

Aqua Publica Europea (APE) is the European Association of Public Water Operators. It unites
publicly owned water and sanitation services and other stakeholders working to promote
public water management at both European and international level. APE is an operator-led
association that looks for efficient solutions that serve public interests rather than
corporate ones.
The organization represents 72 members providing drinking water and sanitation services
to over 90 million citizens across Europe. Its mission revolves around two core objectives:
promoting public water management at the European level and fostering mutual learning
among members. Advocacy efforts primarily target the European Commission and
Parliament, ensuring that public water management remains a priority in European policy
discussions. To facilitate knowledge exchange, the organization runs the Water Erasmus
program, which offers workshops and physical exchanges between operators, promoting
shared expertise and best practices.
Europe, like many regions worldwide, faces increasing water stress due to climate change
and human activities, leading to more frequent droughts, water scarcity, and floods. These
challenges are no longer confined to the Mediterranean but have also become prevalent in
northern Europe, where extreme weather events are intensifying. Compounding the issue is
the growing pressure on water resources from economic sectors critical to the green and
digital transition, such as data centers, energy production, and microchip manufacturing.
These industries are highly water-intensive, escalating the risk of conflicts not only among
users - such as households, agriculture, and industry - but also between regions and
countries. This growing concern has placed drought and water scarcity at the forefront of
the organization’s agenda.

1. x
2. x
The
3. x members of Aqua Publica Europea set the issue of drought and water scarcity as one of
4. x key priorities of the organization. Building on previous exchanges of experiences and
the
15 Rankings.” Technical Note.
5. Luo, T., R. Young, P. Reig. 2015. “Aqueduct Projected Water Stress Country
public
debates with stakeholders, a new publication from Aqua Publica Europea explores
Washington, D.C.: World Resources Institute. Available online at: www.wri.org/publication/aqueductprojected-water-stresscountry-rankingsthat public water operators can deploy to address this critical
the
strategies and approaches
6. https://wad.jrc.ec.europa.eu/waterstress
issue (Figure 32). The publication had two main objectives: to showcase effective water
7. https://wad.jrc.ec.europa.eu/waterstress
management
strategies already implemented by European operators and to encourage
8. x
9. x
stakeholders
10. x
11. x
12. x
13. x
14. https://www.aquapublica.eu/
15. https://www.aquapublica.eu/article/news/ape-publication-resilience-action-public-water-operatorsstrategies-tackle-water

page 47

discussions about the shared responsibility of public water operators, authorities, and
stakeholders in promoting sustainable water use. To compile the publication, members
were invited to share their drought management strategies and water plans, resulting in
contributions from 19 operators. The findings were presented at a European Parliament
event focused on water resilience, highlighting practical approaches and examples for
broader adoption.

Figure 32. Cover of the publication Resilience in Action. Public Water Operators’ Strategies to Tackle
Water Scarcity and Drought (APE).
The publication distinguished between measures operators can implement independently
and those requiring broader stakeholder collaboration. Independent measures include
leakage reduction, exemplified by smart meters used by Parisian operators. These meters
detect abnormal consumption and send real-time alerts, enabling prompt intervention.
Network interconnections also play a crucial role, as seen in Flanders, Belgium, where
interconnected systems ensure a secure water supply across regions facing scarcity.
Additionally, water resource protection initiatives, such as pesticide-free farming practices
promoted by a French member, help safeguard catchment areas. Public awareness
campaigns, like Scotland’s "Water is Always Worth Saving," promote water-efficient
behaviors, while programs like Ireland’s Water Stewardship Accelerator offer on-site
workshops to help industries assess water use and develop conservation strategies.
Measures requiring broader cooperation include water reuse, illustrated by a Belgian
operator supplying treated wastewater to a car manufacturing plant, saving 100,000 cubic
meters of drinking water annually. Nature-based solutions, such as forest infiltration areas
in Italy, allow surface water to recharge aquifers during non-irrigation months, enhancing
both water resilience and biodiversity. Strategic water storage upstream also helps manage
demand,

page 48

demand, but the organization stresses the importance of maintaining ecological continuity
and biodiversity. An example from Italy highlights how a lagoon basin reservoir can sustain
drinking water needs for 15 days during shortages, with plans to expand its capacity from 2
to 5 million cubic meters.
Temporary water restrictions remain a last resort measure during droughts. An Italian
member employs a proactive approach by regularly informing local authorities about
medium-term water outlooks using predictive models. When significant risks arise, an
institutional coordination mechanism adjusts water allocation, particularly for agricultural
use.
The publication's conclusions emphasize four key insights. Accurate data on water quantity
and usage is crucial for effective drought response and long-term planning, yet such data
often remains fragmented and inaccessible to operators. Clear governance frameworks are
essential for guiding decision-making and developing risk management plans. Long-term
territorial planning must consider water availability and the costs of remedial actions.
Finally, new financing mechanisms, complementing volumetric tariffs, are needed to
support sustainable water management. The organization continues to explore these issues
and plans to organize further discussions on innovative financing solutions to address
future water challenges.

page 49

4. Key recommendations to improve cities’
water resilience to water stress
The following key recommendations are derived from the city case studies presented during
the online series, as well as the insights, discussions, and debates that emerged throughout
the online sessions. These recommendations reflect the collective expertise and
experiences shared by participants, offering actionable strategies to address water stress
and build urban resilience.
1. Effective water management requires proactive, adaptive planning informed by
accurate data. As climate change intensifies uncertainty, cities must move beyond
traditional approaches and embrace flexible strategies that can evolve with shifting
conditions. Long-term planning should incorporate forecasting tools that map water
resources and consumption patterns across all sectors, enabling authorities to
anticipate future needs and challenges.
2. Data-driven decision-making is fundamental to sustainable water governance.
Authorities must establish comprehensive water accounting systems that track usage
across sectors such as agriculture, industry, and domestic consumption. Without a clear
understanding of water abstraction and availability, it is impossible to develop realistic,
long-term strategies for water security.
3. Diversification of water sources is essential for resilience. As demonstrated by cities
like Barcelona and Cape Town, reliance on a single source exposes communities to risk.
Investments should be directed toward expanding non-conventional supplies, such as
desalination, groundwater recharge, rainwater harvesting, and water reuse, ensuring
that supplies remain stable during periods of scarcity.
4. Communication plays a pivotal role in fostering public trust and driving
behavioral change. Authorities must develop targeted communication strategies that
convey the urgency of water challenges while combating misinformation. Transparent,
consistent messaging as shown in the example from San Francisco will empower citizens
to make informed decisions and support water-saving initiatives.
5. Equity and fairness must be central to water management policies. Citizens are
more likely to adopt water-saving practices when they perceive that changes are
implemented fairly across all sectors and communities as seen in Douala. Inclusive
policies that prioritize vulnerable populations will ensure that water scarcity does not
deepen existing social inequalities.
6. Cross-sector collaboration is crucial for effective water governance. Water stress is
not solely a municipal issue but intersects with agriculture, energy, and industry. Multistakeholder platforms that bring together public agencies, private sector actors, and civil
society can facilitate holistic, integrated approaches to water management.