How to prevent disruptions by flood and extreme weather events

Source– The post is based on the article “How to prevent disruptions by flood and extreme weather events” published in “The Indian Express” on 15th July 2023.

Syllabus: GS 3 – Disaster management

News-. North-western India and Delhi are facing floods.

Why is there a need for focussed attention on extreme weather events?

Global warming is increasing. If cities are warmed beyond 2 degrees, climatic-impact drivers like extreme rain and heat will increase in intensity. Frequency and intensity of extreme weather will also increase.

The IPCC has shown that this could grow exponentially. It can be much faster than the capacity of our current governance, planning and infrastructure systems.

Massive future disruptions across urban India like flooding, water scarcity and heat waves will increase.

Why are climate impacts and risks like flooding felt intensely in our cities?

One-third of our people and two-third of our economic output is concentrated in densely built-up areas. There is poor water, sanitation, drainage and wastewater infrastructure.

Irrational land use and planning systems exacerbate these challenges and amplify the vulnerability of people who are forced to live in informal settlements and slums.

Cities in sensitive regions along the coast, rivers and hills face even worse impacts, due to higher exposure and locational vulnerability.

What is the way forward for flood management in cities?

Ensuring drainage exists and works: A monsoon audit is done by civic bodies ahead of the season. It ensures that storm water drains, tanks and lakes exist and work properly, and are not choked by construction debris, silt, garbage or blocked by encroachments.

Planning throughout the year and adequate financial and human resources is needed for it, which is not prioritised by civic bodies.

The medium-term solution is the integration of drainage, water supply and wastewater systems to store the intense rain that may come over a short period.

Drainage systems should have enough capacity to deal with the greater intensity of rain caused by changing climate.

Improving roads: The rapid expansion of urban areas has outpaced the development of drainage systems. It has led to many roads functioning as stormwater drains.

It is necessary to enhance the construction and repair practices of city roads to mitigate local flooding.

Currently, when a tar road is repaired, new layers of tar are added. Over time, this leads to an elevated road level compared to the surrounding areas, buildings, and drains. Consequently, these areas and drainage systems become overwhelmed during heavy rainfall.

The situation worsens due to construction of flyovers, underpasses, and sometimes metro lines. It disrupts the existing drainage infrastructure, resulting in significant traffic congestion following floods.

This issue requires effective coordination and infrastructure planning among all relevant agencies.

Greening cities and using blue-green-grey infrastructure: As urban areas expand into concrete landscapes, the capacity for water percolation and flow decreases.

Preserving and safeguarding urban forests, wetlands, rivers, and lakes are crucial in addressing climate change-induced flooding, water scarcity.

China, aims to transform 30 of its megacities into “sponge cities”. It is focussing on green roofs to slow down runoff, urban forests to facilitate percolation and groundwater recharge, and wetlands to absorb and reuse a significant portion of their water resources.

The East Kolkata wetlands have served as an effective flood defence mechanism for over a century. It treats a substantial portion of the city’s sewage.

Practical nature-based blue-green-grey infrastructure initiatives like thai are important for climate adaptation for many cities in India.

Reducing flood vulnerability: India possesses the technological capabilities to conduct comprehensive mapping of all its cities and towns, utilising high-resolution satellite imagery and local topographical data to identify areas most susceptible to flooding.

However, the challenge lies in addressing the vulnerability of people residing along river banks, low-lying areas, and unstable slopes.

Significant progress has been made in terms of evacuation and protecting lives. But, a lot needs to be done for establishing genuine community-based resilience.

One area where notable improvements have been observed is in enhancing forecasting, early warning systems, and evacuation protocols in major cities.

The next step is to extend these measures to all at-risk locations. There is a need for strengthening critical services such as cell phones, power supply, and water infrastructure to ensure their resilience from extreme events.

It is essential to provide all urban residents with access to basic environmental services for safeguarding cities from floods. This includes ensuring reliable water supply, sanitation facilities, effective drainage systems, and proper management of solid waste.