Top Factors Responsible for Urban Flooding and Its Impact

Urban Flooding is one of the major challenges in front of the government today. Due to heavy rainfall, this issue arises every year. This topic is very much in the news so the probability of this coming into exams is very high. Students need to cover this topic in every possible aspect and try to connect the dots with other issues also. kindly bookmark this article for recalling of reason.

Urban Flooding : 

Urban flooding is the inundation of land in built environments, especially in densely populated areas, caused by rainfall that exceeds the capacity of drainage systems.

Main Reasons:

1. Natural reason :

• Increased precipitation: According to IMD, monsoons are becoming more frequent and unpredictable.
  
• Storm surge (for coastal cities): Cyclone Amphan flooded the streets of Kolkata in 2020. In eastern India, the storm killed 98 of her people and cost US$13.8 billion (2020).
  
• Climate change: exacerbated by climate change leading to extreme events. Climate change is increasing the frequency of short-term heavy rains and increasing water runoff.
  

2. Anthropological reasons :

• Drainage erosion: In Indian cities and towns, rising land prices and declining land availability in city centers have led to the emergence of low-lying settlements, usually as erosion into lakes, wetlands, and riverbeds. On the contrary, large-scale interventions were carried out without expanding natural drainage. As a result, the natural drainage capacity is reduced and flooding occurs.
  
• Inability to manage the city’s drainage system: Hyderabad’s floods in October 2020 were caused by the failure to drain water promptly. And when the water was released, it suddenly happened out of control. The unplanned and sudden release of water from dams and lakes causes flooding in urban areas without giving enough time for citizens to react. 
  Example: The 2015 Chennai floods were caused by the release of water from Lake Chembarambakkam.
  
• Outdated Drainage Infrastructure: Most cities have centuries-old drainage systems that were ‘colonially developed’. It covered only a small portion of the central city. Over the last 20 years, these cities have expanded to at least four times their original urban area, but little has been done to remedy the lack of proper drainage systems.  
  
• Destruction of wetlands: The problem of gradual change in land use, especially ignoring wetlands, which are common lands that provide much-needed ecological support. This created an urban terrain that could not absorb, hold or drain water.
  
• The urban heat island effect: It also leads to increased precipitation in urban areas, which leads to flooding. Whenever rain-carrying clouds clear a city’s heat islands, heat can push the clouds up, resulting in very localized rains, sometimes torrential rains.
  
• Unsustainable development: Most of the recent urban flooding in Bangalore is the result of unregulated development in areas such as wetlands and floodplains.
  
• Poor Governance: Urban expansion, often in consultation with city authorities, at the expense of natural drainage. A CAG report (last year) held the Bangalore community responsible for this mismanagement. It was also found that the city of Bangalore did not keep proper records of the stormwater management funds allocated under JNNURM. In 2019, Patna suffered massive flooding in its urban areas in late September. One of the reasons the city government has been unable to fix the problem is that they couldn’t even find a drainage map for the city, which has a population of 5.8 million according to the 2011 Census.
  According to a 2010-2011 report by the Department of Urban Development, stormwater coverage, essential to drain large amounts of runoff during short periods, such as heavy rainfall, was 56 out of 104 cities that submitted responses. In cities, it fell below 50%. Bengaluru, a flooded city at this time, only 10% of the streets were covered by storm runoff. Local governments do not understand drainage requirements and lack the resources to develop such capacity.
  
• The Ethical Dilemma Between Development and Environment: A policy that prioritizes environmental concerns over construction should deny approval for many construction activities in India, especially in cities.  This inevitably results in economic losses for those working in the sector and increases housing costs for those looking to purchase such homes. Given the growing importance of the Indian real estate sector, this is not an easy decision.
  
• Illegal Mining Activities: Illegal mining of river sand and quartzite for use in construction is depleting the natural beds of rivers and lakes. It causes soil erosion, reduces the water-holding capacity of water bodies, and increases the speed and magnitude of water flow. Examples: Jaisamand Lake – Jodhpur, Cauvery River – Tamil Nadu.
  

Impacts :

• Loss of life and property: Urban flooding is often associated with loss of life and bodily injury, either directly from the impact of flooding or indirectly from water-borne disease transmission that spreads during flood season. I’m here. 
  
• Disruption of public services: Urban floods have localized effects such as structural damage to buildings, property, and crops. It also disrupts water, sewage, power lines, communications, road and rail traffic, and other infrastructure.
  
• Psychological Impact: Losing shelter or relatives creates emotional turmoil in the mental health of stranded people. The recovery process from such incidents is difficult, time-consuming, and often results in long-term psychological trauma. 
  
• Ecosystem Impact: Trees and plants are washed away during extreme floods, and erosion of embankments is caused by high-velocity floods.