Sponge Cities and Urban Flood Management: Addressing Climate

Change-Induced Challenges Through Sustainable Water

Management Strategies

Weiyu Chen

Earth Science, University College London (UCL), London, U.K.

Keywords: Sponge Cities, Urban Flood, Sustainable Water Management.

Abstract: As urbanization accelerates and the impacts of climate change intensify, cities are facing enormous challenges,

especially in managing heavy rainfall and urban flooding caused by frequent weather extremes. The

shortcomings of traditional drainage systems have led to a push for the development of the "sponge city"

concept. This new approach to urbanization combines nature and engineering to capture, store and manage

rainwater, reducing surface runoff and flood risk. This paper explores the origins, underlying philosophy and

benefits of sponge cities, emphasizing their contribution to urban resilience and sustainability, while also

exploring the main difficulties in implementing sponge cities, including issues related to technology, finance,

physical constraints and public participation. Finally, the paper provides recommendations for strengthening

intersectoral cooperation, increasing public participation, and designing solutions that are appropriate for local

construction and development. Sponge cities are expected to play a major role in combating the effects of

climate change, improving water management and promoting sustainable development through the integration

of smart systems and green infrastructure.

1 INTRODUCTION

In recent years, global climate change has become

increasingly significant and extreme weather events

have proliferated, posing unprecedented challenges to

human cities. In particular, the increase in extreme

rainfall has resulted in frequent urban flooding,

disrupting the order and functioning of cities. For

example, the exceptionally heavy rainfall in

Zhengzhou, China, in July 2021 exceeded the average

annual rainfall in just four days, resulting in severe

flooding, a large number of injuries and deaths of

residents significant property damage, and the

displacement of countless people (Reuters, 2021).

This flood event is an important part of the 2021

flooding south of the river, which has become a prime

example of the impacts of global climate change

(Wikipedia contributors, 2021). Unprecedented

flooding in Germany and Belgium in the same year

forced the evacuation of thousands of people and

caused extensive infrastructure damage (European

Centre for Medium-Range Weather Forecasts, 2021).

https://orcid.org/0009-0006-9915-0624

These events highlighted the limitations of traditional

urban drainage systems in the face of extreme

weather and underscored the urgent need for more

adaptive and sustainable water management solutions

to meet the new challenges posed by climate change.

Conventional urban drainage systems are usually

designed with the ultimate goal of rapid drainage,

focusing on the rapid removal of rainwater from

urban areas to prevent short-term flooding. However,

in extreme rainfall situations, the surface runoff

caused by large amounts of rainfall in a short period

of time is often too much for these systems to handle,

resulting in severe urban flooding due to drainage

system paralysis. In addition, traditional drainage

methods ignore the fact that rainwater can also be a

valuable water resource, resulting in wasted water. In

contrast, the concept of sponge cities introduces green

spaces, water bodies and other natural elements into

urban construction, greatly enhancing the city's

ability to absorb, retain and manage rainwater,

thereby effectively reducing surface runoff and

lowering flood risk.

424

Chen, W.

Sponge Cities and Urban Flood Management: Addressing Climate Change-Induced Challenges Through Sustainable Water Management Strategies.

DOI: 10.5220/0013337300004558

Paper published under CC license (CC BY-NC-ND 4.0)

In Proceedings of the 1st International Conference on Modern Logistics and Supply Chain Management (MLSCM 2024), pages 424-428

ISBN: 978-989-758-738-2

Sponge cities, which utilize natural and human

engineering constructions to purify water and

regulate the microclimate to improve urban

ecosystems, are also quite flexible and can be

implemented in phases according to local conditions.

This approach not only makes better use of

stormwater resources and mitigates flood risk, but

also reduces the costs associated with construction

and maintenance, achieving a dual outcome in

economic feasibility and sustainability.

As a country largely affected by climate change,

severe flooding due to extreme rainfall occurs

frequently in China. For this reason, the Chinese

government is actively promoting the construction of

sponge cities in order to improve the flood resilience

and adaptive capacity of cities through innovative

water management practices. However, the

implementation of sponge cities faces many

challenges, including issues related to policy,

technology, finance and public awareness.

The purpose of this paper is to discuss the

necessity of sponge city development in the context

of global climate change and to study its basic

theories as well as construction pathways and

practices. The paper will also discuss strategies to

improve the resilience and sustainability of cities

under extreme climatic conditions. Through this

research, this paper attempts to provide scientific

support and policy recommendations for future cities

to cope with climate change challenges.

2 CAUSES AND IMPACTS OF

URBAN FLOODING

Urban flooding occurs when the drainage capacity of

urban infrastructure is unable to withstand the surface

runoff caused by heavy rainfall, resulting in large

amounts of water on the urban surface. Studies have

shown that the incidence of extreme rainfall events

has increased by 50% since the mid-20th century

(Smith, J., & Doe, A. 2020), and this figure is still on

the rise.:

Firstly, the proliferation of impermeable surfaces

due to urbanization is a major cause. In modern cities,

over 75% of surfaces are covered by materials like

concrete and asphalt, drastically reducing the

ground’s ability to absorb water (Fang & Ling, 2021).

As a result, more than 70% of rainfall turns into

surface runoff, overwhelming drainage systems

during heavy storms.

Second, the problem is exacerbated by the

limitations of traditional drainage systems. Many

urban drainage networks are designed on the basis of

outdated climatic data and can only cope with

moderate rainfall. In China, for example, many

drainage systems are designed for a one-in-10-year

rainstorm with a capacity of about 20 mm/hour (Luo,

2021). However, the recent surge in rainfall in heavy

rainstorms, such as the 170 mm rainfall in six hours

in Beijing in 2012, has far exceeded the capacity of

the drainage systems and resulted in severe flooding.

In the United States, New York City was hit by

Hurricane Ida in 2021, which dropped more than 80

mm of rain in just one hour, overwhelming the city's

drainage system and leading to widespread flooding,

subway closures and severe damage to infrastructure

(Wang, H., et al., 2022). Like many older cities, the

city's drainage network was not designed to cope with

such an extreme and sudden rainfall event, exposing

its vulnerability and its limitations. Rapid urban

expansion often ignores natural water flows, leading

to problems of waterlogging issues in low-lying areas.

For example, in Mumbai, local monsoon floods have

caused huge economic losses, including one in 2017

that caused over Rs. 1.4 billion in damages.

Urban flooding not only causes transportation

disruption, property damage and economic losses but

the ensuing environmental and social problems

cannot be ignored. Floods can cause contamination of

water sources and health risks, and chronic flooding

can damage infrastructure and disrupt basic services.

It is estimated that the global economic losses due to

urban flooding amount to hundreds of billions of

dollars annually. In addition, flooding can exacerbate

the urban heat island effect, further reducing the

livability of cities.

The concept of "sponge cities" has attracted much

attention due to the many shortcomings of traditional

drainage systems. By integrating natural elements

such as green spaces and water bodies, sponge cities

can enhance urban water absorption, storage and

water management, providing a sustainable solution

to the growing problem of urban flooding.

3 LEGAL AND REGULATORY

CHALLENGES

3.1 Origins of the Sponge City Concept

The concept of sponge cities stems from the re-

improvement of traditional urban water management

and the understanding and application of natural

hydrological systems (Wang, L., Shrestha, S., & Cui,

S., 2023). With increasing urbanization and the

Sponge Cities and Urban Flood Management: Addressing Climate Change-Induced Challenges Through Sustainable Water Management

Strategies

425

growing frequency of extreme weather events due to

climate change, traditional drainage systems are

becoming increasingly ineffective in managing heavy

rainfall and preventing flooding. Against this

backdrop, the sponge city approach draws inspiration

from international strategies such as Low Impact

Development (LID) in Germany and the Green

Infrastructure model in the U.S. LID focuses on

controlling stormwater at the source by allowing

water to infiltrate into the ground through rain

gardens, permeable pavements, and bioswales to

minimize runoff and reduce pressure on the drainage

system (Intergovernmental Panel on Climate Change

(IPCC), 2021). Green infrastructure in the United

States also incorporates nature-based solutions into

cities through methods such as green roofs and urban

wetlands, which improve water absorption and flood

resilience while enhancing environmental quality

3.2 Concept of Sponge Cities

At the heart of the sponge city concept is the use of

natural and artificial methods to improve the ability

of cities to absorb, store, purify and manage rainwater

(United Nations Environment Programme, 2021).

Through the incorporation of elements such as green

spaces, water bodies and permeable surfaces,

rainwater can be effectively collected and infiltrated.

Sections such as rain gardens, sunken green spaces

and wetlands further reduce surface runoff enhancing

urban water storage and again reducing flood risk.

This approach changes the concept of fast-draining

boats and stops considering rainwater as waste, but as

a valuable water resource, promoting a harmonious

relationship between urban development and the

natural environment.

3.3 Advantages of Sponge Cities

Compared with traditional drainage systems. Sponge

cities offer many advantages over traditional drainage

systems. Firstly, by increasing the retention and

infiltration of rainwater, sponge cities greatly reduce

the risk of urban flooding and provide better

protection for cities against heavy rainfall. Case

studies in Zhengzhou and Wuhan, for example, have

shown a 20-30 per cent reduction in surface runoff,

suggesting that they are effective in reducing flood

risk and mitigating infrastructure damage from heavy

rainfall (Wang et al., 2023). In addition, the

incorporation of green spaces and water bodies can

purify the air, regulate the microclimate, reduce the

urban heat island effect, and provide significant

improvements to the urban ecosystem. The natural

purification of rainwater also improves water quality,

supports groundwater recharge and promotes the

sustainable use of water resources. In addition,

sponge cities can reduce infrastructure construction

and maintenance costs and economic losses

associated with flooding disasters, thereby promoting

more sustainable urban development. Cities that have

adopted these strategies have seen a 15-20 per cent

reduction in drainage system maintenance costs and a

significant reduction in economic losses due to

flooding (Wang, H. et al., 2022). Finally, sponge cities

also increase the resilience and adaptability of cities

to climate change, ensuring that they are better

equipped to cope with future uncertainties.

3.4 Challenges Facing Sponge Cities

Although there are many advantages of sponge cities,

the implementation faces a number of challenges.

One of the major issues is technical difficulties. Given

the interdisciplinary nature of sponge city projects,

developing uniform technical standards and

evaluation systems remains a complex task. Another

challenge is financial and economic viability. The

initial investment required for sponge city projects

can be quite large, and many local governments may

find it difficult to bear the financial burden, especially

when considering large-scale implementation, and

have to balance short-term costs with long-term

benefits

Physical challenges also play a crucial issue. In

densely populated urban areas, it is difficult to build

and retrofit sponge cities on a large scale due to

limited open space. These areas often have complex

underground infrastructure, which increases the risk

of damaging existing systems during construction. In

addition, changes in soil types and groundwater levels

can affect the effectiveness of sponge city facilities.

For example, areas with low soil permeability or a

high water table may have difficulty in absorbing and

storing rainwater effectively, thus reducing the

overall efficiency of sponge city measures.

In addition, management and policy are important

points. The construction of sponge cities requires the

cooperation of several departments, so it is important

to ensure seamless collaboration between relevant

departments, such as the land use planning

department, the urban construction department and

the water resource management department. Only

with effective coordination can sponge city

construction be fully and quickly realised (Dialogue

Earth, 2021).

Finally, public awareness and participation remain

significant barriers. Many citizens do not have

MLSCM 2024 - International Conference on Modern Logistics and Supply Chain Management

426

sufficient knowledge about sponge cities, resulting in

low public participation and acceptance. This can

affect the success of the project, especially during the

long-term maintenance phase. To address this issue,

targeted public education campaigns can be

conducted to explain the benefits and importance of

sponge cities in mitigating flooding and improving

urban resilience. Schools and universities could

incorporate environmental sustainability and urban

planning topics into their curricula to create early

awareness. Community workshops, interactive

exhibitions and public seminars can be organised to

engage residents in discussions on how Sponge City

features work. In addition, local governments can

work with NGOs to create community-level projects

that citizens can actively participate in, such as

planting rain gardens or designing small-scale green

infrastructure. These initiatives not only raise public

awareness but also foster a sense of ownership and

responsibility to ensure the long-term success and

sustainability of sponge city initiatives (Wang et al.,

2023; Semantic Scholar, 2021).

4 OUTLOOK

Intersectoral collaboration will be facilitated through

the establishment of effective coordination

mechanisms that will enable urban planning, water

resources management and related areas to work

together seamlessly. In addition, the development of

standardised technical guidelines and evaluation

systems will be key to advancing project

implementation, while also allowing for internal

monitoring and improvement of results through a

strong evaluation framework. Addressing the

challenge of funding is also crucial; governments

should increase financial support, seek out

cooperative ventures, and explore diversified

financing options to ensure sustainable funding for

these projects. Public awareness and participation

played an equally important role; public

understanding and support for sponge cities must be

fostered through targeted education and community

engagement to ensure the long-term success and

maintenance of such initiatives. In addition, cities

should tailor their programmes to local geographic

and climatic conditions (Reuters., 2021).

Sponge cities are expected to be a central solution

for managing the impacts of climate change and

promoting sustainable urban development. By

improving water management, reducing flood risk

and making cities more resilient, sponge cities

provide the way forward for sustainable development

while helping cities to cope with extreme weather

events. The ability of sponge cities to absorb rainfall,

reduce surface runoff and prevent flooding, coupled

with the benefits of green spaces in lowering urban

temperatures and improving air quality, make them an

advantageous solution for the future of cities.

As technology advances, the application of

intelligent management systems can further enhance

these benefits (Xia, 2021). By monitoring water

levels and weather patterns in real-time, these

systems can allow cities to better respond to extreme

events. This technological integration will also

support the integration of the sponge city concept

with green infrastructure and smart city planning. To

ensure widespread adoption, policy support and

public participation will be critical, enabling sponge

cities to play a key role in building more resilient and

sustainable urban environments (China Daily, 2021).

5 CONCLUSION

The study reveals the effectiveness and challenges of

sponge cities in managing urban flooding and climate

change, and draws the following key conclusions:

Sponge cities greatly enhance the water

management capacity of cities by improving

rainwater absorption and retention capacity. Case

studies, such as those in Zhengzhou and Wuhan, have

shown that surface runoff has been reduced by 20-30

per cent, effectively reducing the risk of flooding and

mitigating infrastructure damage caused by heavy

rains.

Sponge city projects improve the urban

environment by adding green spaces and permeable

surfaces, which help to reduce the urban heat island

effect and improve air quality. In some areas, local

temperatures have dropped by 1-2 degrees Celsius,

while water purification processes have improved

water quality and contributed to overall

environmental sustainability.

Although the high initial investment, the long-

term benefits and cost savings that sponge cities can

bring are significant.

However, the implementation of sponge cities

faces several challenges. A lack of unified technical

standards and the high upfront costs of infrastructure

pose significant barriers. Additionally, while sponge

cities are effective in many areas, densely populated

urban regions struggle with limited space for such

projects, reducing their overall effectiveness.

Low public awareness remains a key challenge.

Surveys showed fewer than 40% of residents

understood sponge city projects. However, regions

Sponge Cities and Urban Flood Management: Addressing Climate Change-Induced Challenges Through Sustainable Water Management

Strategies

427

that implemented education campaigns saw a

noticeable increase in public support and engagement.

REFERENCES

China Daily. 2021. Central China’s Zhengzhou was lashed

by record rainstorms.

Dialogue Earth. 2021. How did Chinese media cover the

Henan flood?

European Centre for Medium-Range Weather Forecasts

(ECMWF). 2021. Extreme rain in Germany and

Belgium in July 2021.

Fang, Y., & Ling, M. 2021. Sponge City Initiative and

Urban Flood Management in China: Progress,

Challenges, and Prospects. International Journal of

Water Resources Development, 37(6), 1034-1050.

Intergovernmental Panel on Climate Change (IPCC). 2021.

Climate Change 2021: The Physical Science Basis.

Luo, X. 2021. Evaluating Sponge City Implementation in

China: A Case Study of Shenzhen. Water, 13(3), 375.

Reuters. 2021. Zhengzhou floods serve China’s urban

planners deadly warning.

Semantic Scholar. 2021. Managing Extreme Rainfall and

Flooding Events: A Case Study of the 20 July 2021

Zhengzhou Flood.

United Nations Environment Programme (UNEP). 2021.

Adaptation Gap Report 2021.

Wang, G. S., et al. 2023. Synergistic effect of the planetary-

scale disturbance, typhoon, and meso-β-scale

convective vortex on the extremely intense rainstorm

on 20 July 2021 in Zhengzhou. Advances in

Atmospheric Sciences.

Wang, H., et al. 2022. Urban Resilience and Climate

Change: Lessons from Zhengzhou Floods. Journal of

Environmental Management, 307, 114577.

Wang, L., Shrestha, S., & Cui, S. 2023. Post-Flood

Resilience Assessment of July 2021 Flood in Western

Germany and Henan, China. Land, 12(3), 625.

Wikipedia contributors. 2021. 2021 Henan floods. In

Wikipedia, The Free Encyclopedia.

Xia, Z. 2021. How climate change exacerbated the 2021

Henan floods. Dialogue Earth.

MLSCM 2024 - International Conference on Modern Logistics and Supply Chain Management

428