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The Impact of Urbanization on Flood Risk

February 15, 2023 | Created by: Andreas Klippe | Comments

As urban areas continue to expand, the impacts on the natural environment become increasingly evident. One of the most pressing concerns is the increased risk of flooding. The effects of urbanization on flood risk are complex and multifaceted, but there are five key factors to consider.

1. Increased Surface Runoff

Urbanization, through the construction of impervious surfaces like concrete, asphalt, and buildings can reduce the ability of the land to absorb water. Instead, water runs off the surface quickly, often overloading drainage systems and leading to flooding. 

This process is called increased surface runoff. In urban areas, roads and buildings can create large amounts of runoff, which often exceeds the capacity of drainage systems. This can result in flash flooding, property damage, and a range of negative consequences for both people and the environment. 

Concrete and asphalt covering the natural absorption of soil cause an increase in surface runoff that leads to massive flooding.

Managing surface runoff in urban areas is therefore critical to reducing the negative impacts of urbanization on flood risks.

2. Drainage System Overload

The rapid increase in urbanization can lead to low drainage capacity due to poor urban planning. Urbanization is often accompanied by an increase in land use for residences, commercial establishments, and other infrastructure. As the number of buildings and impervious surfaces increases, the demand for drainage systems also grows. 

Poor urban planning can result in the development of high-rise buildings and other structures that produce significant amounts of domestic wastewater and commercial waste. As a result, the drainage systems may not have the capacity to manage the increasing volumes of water that are generated.

Floodwater overflowing thru a manhole of a drainage system
Poor drainage system causes flood water to overflow and submerge the streets.

Inadequate drainage systems and overburdened stormwater systems can result in increased flooding, erosion, and water pollution. These issues can have a significant impact on the health and safety of individuals and communities. To address this problem, policymakers and urban planners should prioritize the implementation of sustainable drainage systems that can accommodate the growing demand for drainage. 

3. Floodplain Encroachment

In urban areas, the demand for land is very high, and floodplains are often seen as prime areas for development. This leads to Floodplain Encroachment which forces the development of land in areas that are prone to flooding. 

vietnam rever-side settlement from 2002 to 2021
Vietnamese riverside settlement growth in Quảng Nam between 2002 (left) and 2021 (right) shows the expansion of development on the floodplain area of the river.

However, this increases the risk of flooding, as the natural capacity of the floodplain to absorb and store water is greatly reduced. Floodplains that have been built on are unable to retain water, so excess water from rainfall events is channeled more quickly into rivers and streams, increasing the risk of flooding downstream. 

To mitigate the impact of floodplain encroachment, urban planners and policymakers should prioritize the use of green infrastructure, zoning regulations, and other flood risk management strategies in urban areas.

Additionally, property owners who are located in flood-prone areas can take steps to protect their assets from flood damage by investing in modern flood control devices such as Demountable Flood Barriers. By implementing effective flood risk management strategies, urban areas can reduce the impact of floodplain encroachment and protect their residents from the negative consequences of flooding.

4. Loss of Wetlands

Wetlands is a vital part of the earth’s ecosystem, playing a crucial role in regulating the water cycle. They can absorb and store large amounts of water, reducing the volume of runoff that enters streams and rivers during heavy rain events. 

However, urbanization often leads to the loss of these essential ecosystems, which can increase the risk of flooding. The loss of wetlands due to urbanization can have several negative impacts on the environment. Wetlands support a diverse range of plant and animal species, and their destruction can lead to the loss of biodiversity. Additionally, wetlands serve as natural water filters, removing pollutants and improving water quality.

When wetlands are lost due to urbanization, the water that would have been absorbed and stored in the wetland is instead channelled downstream, increasing the volume of runoff and the risk of flooding. This can result in significant damage to property, infrastructure, and even loss of life.

5. Climate Change Impacts

Urbanization is one of the significant factors contributing to climate change. With more people moving to urban areas, the demand for energy and resources increases, leading to more factories and the need for more electricity. This increased energy consumption means more fossil fuels are burned, which, in turn, leads to higher greenhouse gas emissions. These emissions contribute to climate change and increase the frequency and severity of extreme weather events like storms and floods.

As urbanization continues, the demand for energy increases, and coal-fired power plants have been one of the primary sources of energy for many years.

As the earth’s climate continues to change, we’re seeing an increase in severe storms, with heavier rainfall than ever before. Urbanization has exacerbated this issue, as rainwater that falls on pavement and other impervious surfaces is not absorbed by the soil. Instead, it flows quickly into streams and rivers, leading to flash flooding and significant damage to property and infrastructure.

Areas that are not usually prone to flooding are now experiencing severe flooding due to this phenomenon. The lack of green spaces and wetlands in urban areas means there is little natural water absorption. When there is a heavy rainfall event, there is nowhere for the water to go, and the result is often devastating flooding. This phenomenon can also lead to an increased risk of landslides, as the ground becomes saturated with water.

We must take urgent action to address the root causes of these issues and implement policies that encourage sustainable urban development, such as the use of green infrastructure and the promotion of renewable energy sources. By working together, we can mitigate the negative effects of urbanization on climate change and ensure a safer, more sustainable future for all.

Preparing for the Inevitable: Investing in Flood Mitigation Solutions

In conclusion, urbanization has significant negative impacts on flood risk. Increased surface runoff, floodplain encroachment, drainage system overload, loss of wetlands, and climate change impacts all contribute to the increased likelihood and severity of flooding in urban areas. As our cities continue to grow, it is crucial that we take proactive measures to mitigate the impacts of urbanization on flood risk.

Although we cannot stop urbanization altogether, we can take steps to reduce its negative impact. One way is to invest in flood mitigation devices like the Demountable Flood Barrier. By doing so, we can protect our properties and ensure that we are prepared for future flooding events. Additionally, seeking the guidance of flood experts like us can provide helpful insights and strategies for reducing flood risk in urban areas.

demountable flood barrier was installed at FEU Roosevelt
A university in Marikina, Philippines proactively responded to flooding by installing German technology RS Demountable flood barriers. 

At the end of the day, we must all do our part to protect ourselves and our communities from the dangers of flooding. By taking proactive measures and investing in effective flood protection, we can make our cities more resilient and better equipped to handle the challenges of urbanization and climate change.

If you want to know more about how to effectively protect your property against flooding, we can provide expert advice and solutions tailored to your specific needs. Contact us today to learn more about our flood mitigation products and services.

Remember, flooding is a serious issue, but by working together, we can make our communities more resilient and better prepared for the future.

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