Sponge-city concept may mitigate flooding

Sponge
cities

·      
About: The
"sponge city" is an urban planning model designed to use "nature-based solutions"
to distribute water better and improve drainage
and storage. Those solutions included the use of permeable
asphalt, the construction of new canals and ponds and also the restoration of
wetlands, which would not only ease waterlogging but also improve the urban
environment.

·      
Rainwater Absorption and
Retention: Sponge cities are designed to absorb and retain
rainwater, reducing the volume of water that flows into drainage systems during
heavy rainfall. Example:
Rooftop gardens, permeable pavements, and open green spaces are integrated into
urban designs to allow rainwater to infiltrate into the ground.

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Natural Water Storage:
The concept involves creating natural storage areas, such as
wetlands and ponds, to hold excess rainwater and prevent it from overwhelming
drainage systems. Example:
The Tianjin Eco-City in China incorporates wetlands that function as water
storage during heavy rains, reducing the risk of flooding.

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Green Infrastructure:
Vegetation and green infrastructure, like bioswales and urban
forests, are critical components of sponge cities that help slow down and
absorb rainwater. Example:
Singapore's Marina Barrage features a lush urban park that doubles as a water
catchment area, preventing downstream flooding.

·      
Improved Drainage Systems:
Sponge cities often include enhanced drainage systems that
manage water flow more efficiently and prevent localized flooding. Example: The Sponge City Initiative in
Wuhan, China, involves upgrading drainage networks and using sensors to monitor
water levels in real time.

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Improved water table:
The use of permeable surfaces like permeable pavement and
porous concrete allows rainwater to seep into the ground rather than pooling on
surfaces. Example:
In Melbourne, Australia, the Water Sensitive Urban Design approach includes
permeable pavement in parking lots, reducing surface runoff.

·      
Floodplain Management:
By creating and preserving natural floodplains, sponge cities
provide space for water to spread out, reducing the risk of inundation. Example: The Thames Barrier in London, UK,
is a flood control structure that protects the city by preventing storm surges
from entering the river Thames.

·      
Climate Resilience:
Sponge cities are designed to adapt to changing weather
patterns, making them more resilient against increased rainfall due to climate
change. Example:
Copenhagen, Denmark, has adopted a sponge city approach to address rising sea
levels and heavy rainfall, incorporating green roofs and permeable surfaces.

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Challenges: High Initial Costs-
Developing and retrofitting urban areas to become sponge cities
can require significant investments in infrastructure, technology, and green
spaces.

Maintenance
Demands- Maintaining green infrastructure,
drainage systems, and water storage features requires ongoing resources,
funding, and skilled labour.

Integration
with Existing Infrastructure-
Retrofitting existing urban infrastructure to fit sponge city
principles can be logistically challenging and require careful coordination.

Interconnected
Systems- Ensuring that different water
management components (e.g., green roofs, drainage, and water storage) work
together seamlessly can be challenging.

Resistance
to Change- Overcoming resistance from
traditional urban planning practices and stakeholders accustomed to
conventional systems.