Context
Bengaluru rain has led to widespread waterlogging, severe damage and traffic disruptions. Environmentalists and water conservationists highlighted the poor status of the city’s current drainage system. They blamed its outdated and ill-equipped drainage system for managing the city’s current population and rainfall intensity. Below, we have discussed about Urban Flooding: Rising Issue of Cities in detail.
What are Floods?
Floods are the most frequent type of natural disaster and occur when an overflow of water submerges land that is usually dry.
Types of Floods
(a) Flash floods: Caused by rapid and excessive rainfall that raises water heights quickly. So rivers, streams, channels or roads may be overtaken.
(b) River floods: Caused when consistent rain or snow melt forces a river to exceed its capacity.
(c) Coastal floods: Caused by storm surges associated with tropical cyclones and tsunamis.
(d) Urban flooding: Occurs as a result of land development. Permeable soil layers are replaced by impermeable paved surfaces, through which water cannot infiltrate.
Causes of Urban Flooding
(i) Unplanned Rapid Urbanisation: Disproportionate urban growth has destroyed natural drainage systems. It led to transgression of floodplains and wetlands, impermeable surfaces due to concrete construction, and changes in watershed boundaries..
(ii) Lack of Effective Urban Governance: In spite of the 74th Constitutional Amendment Act, urban planning, land use, and economic development have not fully transferred to city governments. Insufficient clarity results in uneven distribution of power between elected representatives and executive wings. This results in poor urban governance and management of waterlogging issues.
(iii) Inadequate and Outdated Drainage Infrastructure: Many Indian cities still rely on old-age drainage systems designed for 20-25mm/hour of rainfall. They are inadequate for current precipitation patterns.
(iv) Climate Change and Extreme Weather Events: Increase in the occurrence and intensity of rainfall events in India. So the volume of water > the drainage systems can handle. Coupled with the soil’s inability to absorb water quickly exacerbates the situation.
(v) Loss of Water Bodies and Green Spaces: The National Institute of Urban Affairs reported that major Indian cities have lost 70-80% of their water bodies in the last 40 years. This resulted in reduced natural water storage capacity, increased surface runoff, and destruction of the water cycle.
Impact of Urban Flooding
(i) Loss of Lives and Injuries: People can become trapped or swept away in submerged areas, resulting in fatalities and injuries.
(ii) Damage to Infrastructure: It can result in huge damage to physical infrastructure. Homes, businesses, and public facilities can be flooded or destroyed, causing huge financial losses for individuals, communities, and the government
(iii) Displacement of Vulnerable Population: Poor individuals forced to vacate their houses and search for temporary shelter.
(iv) Disruption of Vital Services: Essential services like electricity, water supply, and communication networks get badly damaged. Eventually, exacerbates hardships for affected communities and hinders rescue and relief efforts.
(v) Waterborne Diseases: It can increase the risk of waterborne diseases such as cholera, typhoid, and diarrhoea.
Government Initiatives
(i) Swachh Bharat Mission (Urban): Apart from sanitation, it also emphasises solid waste management and pollution control, which contribute to preventing waterlogging and flooding.
(ii) National Smart Cities Mission: It promotes the measures to manage urban flooding through rainwater harvesting, green spaces and a proper drainage system.
(iii) Atal Mission for Rejuvenation and Urban Transformation (AMRUT): The Mission focuses on developing basic urban infrastructure in cities and towns, particularly in the areas of water supply, sewerage and septage management, and stormwater drainage.
(iv) Guidelines and Regulations: The government has issued guidelines for sustainable urban development, encouraging the incorporation of features like permeable pavements, green roofs, and retention ponds to enhance water absorption.
India’s Smart Cities Mission: Operational Framework & Achievements
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Way Forward
(i) Capacity Development of ULBs: There is a need to foster staff to learn new skills by giving appropriate incentives. State governments and ULBs should give preference to rebuilding the basic structure of local government institutions. Along with adequate staff, appropriate training facilities should also be there.
(ii) Water-Sensitive Urban Design and Planning: Water-sensitive urban design and planning techniques should be mandatory. It includes land features, surface types, natural water flow, and has minimal environmental impact.
(iii) Adopting Scientific Management Measures: Initiatives should begin with mapping areas vulnerable to waterlogging. Hydraulic and hydrological models should analyze flood patterns, with results incorporated into urban master plans.
(iv) Decentralised Stormwater Management: Promoting decentralised stormwater management techniques. For eg, rainwater harvesting, bioswales, and absorbing ponds can reduce waterlogging at the regional level.
(v) Smart Drainage Systems: Use advanced technology like sensor-based drainage systems that can determine water levels and control flow in real-time, and can ameliorate the functioning of urban drainage networks.
(vi) Green Infrastructure: Installing green roofs, rain gardens, bioswales, permeable pavements, and urban green spaces can absorb rainwater. It also reduces surface runoff, eventually decreasing strain on drainage systems.
(vii) Nature-Based Solutions: Restoration of natural wetlands, creation of urban forests, and revitalisation of water bodies can enhance natural water absorption. Also, it can reduce waterlogging.
Conclusion
Converging engineering solutions, smart urban planning, real-time technologies, and community participation are a must-do step in building flood-resilient cities. Consequently, it will effectively mitigate the challenge of urban flooding in India.