QUESTION : Exemplify the term “ Sponge City” and Discuss its relevance for Indian urban landscape.
TIME FOR A ‘SPONGE CITIES’ MISSION IN INDIA
WHY IN NEWS ?
The torrential rains in Hyderabad killed over 50 people. In the past, it was Chennai that saw a massive flood costing much damage and lives. For Mumbai, the monsoon has become synonymous with flooding and enormous damages
WHAT IS URBAN FLOODING ?
- Flood is defined as “an overflow of a large body of water over areas not usually inundated”. Thus, flooding in urban areas is caused by intense and/or prolonged rainfall, which overwhelms the capacity of the drainage system.
- Urban flooding is significantly different from rural flooding- urbanization increases flood risk by up to 3 times, increased peak flow results in flooding very quickly. Further, it affects large number of people due to high population density in urban areas.
CAUSES OF URBAN FLOODING :
- Meteorological Factors:
Heavy rainfall, cyclonic storms and thunderstorms
- Hydrological Factors:
Overbank flow channel networks, occurrence of high tides impeding the drainage in coastal cities.
- Anthropogenic Factors:
Unplanned Urbanization is the key cause of urban flooding. A major concern is blocking of natural drainage pathways through construction activity and encroachment on catchment areas, riverbeds and lake beds.
IMPACT OF URBAN FLOODING :
1.Impact on Human:
- Loss of life & physical injury
- Increased stress; psychological trauma
- Contamination of water supplies leading to diseases
- Rise in mosquito borne diseases
3.Impact on Economy:
- Damage to buildings, roads and other infrastructures
- Disruptions to industrial production
- Disruptions to utility supplies
- Impact on heritage or archaeological site
- Post-disaster rescue and rehabilitation adds to financial burden of the government
4.Impact on Transport and Communication:
- Increased traffic congestion, disruption in rail services
- Disruption in communication- on telephone, internet cables
5.Impact on environment:
- Loss of tree cover, loss of habitat
- Impact on animals in zoo, stray animals
THE RECENT CASE OF HYDERABAD :
- Unprecedented rainfall: In September 2019, the rainfall was the highest in 100 years. The rainfall received in 2020 has been the highest for the month of October in a century.
- Ignoring scientific tools: Scientists from the Potsdam Institute for Climate Impact Research, Germany, built climate change adaptation tools for Hyderabad. However, the Hyderabad Metropolitan Development Authority did not use it.
- Mismanaging the city’s drainage systems:
o The floods of October 2020 occurred because we did not discharge the water in time.
o And when we did discharge the water, we did it in a sudden, uncontrolled manner.
- Antiquated infrastructure:
o Hyderabad’s century-old drainage system (developed in the 1920s) covered only a small part of the core city.
o And as the city grew beyond its original limits, not much was done to address the absence of adequate drainage systems.
- Communities left out: The issues of incremental land use change, particularly of those commons which provide us with necessary ecological support — wetlands were neglected.
o The role of local communities in managing local ecosystems — people with traditional rights for fishing and farming was also ignored.
WHAT IS A ‘SPONGE CITY’ ?
- A great risk that climate change introduces to urban centers is flooding due to unpredictable and extreme weather patterns. Hence, sponge cities are urban ecosystems that are designed to take advantage of the floods, rather than letting them destroy livelihoods. These cities tap into biophilic urban design elements like green roofs, open green spaces, and interconnected waterways that can naturally detain and filter water
- A sponge city follows the philosophy of innovation: that a city can solve water problems instead of creating them. In the longrun, sponge cities will reduce carbon emissions and help fight climate change.
- These can all be delivered effectively through an urban mission along the lines of the Atal Mission for Rejuvenation and Urban Transformation (AMRUT), National Heritage City Development and Augmentation Yojana (HRIDAY) and Smart Cities Mission.
NATIONAL FLOOD COMMISSION :
- Rashtriya Barh Ayog or the National Flood Commission (NFC) was set up by the Ministry of Agriculture and Irrigation in 1976.
- It aimed to study India’s flood-control measures after the projects launched under the National Flood Control Programme of 1954 failed to achieve much success
WHY REVIVE NFC?
- An accurate estimate is crucial for framing flood management programmes.
- The NFC estimated that the total area vulnerable to floods in 1980 was around 40 million hectares.
- There is another problem. The very definition of the flood-prone area does not reflect the effectiveness of the flood management works undertaken.
WAY FORWARD :
- Ban against terrain alteration:
Builders, property owners, and public agencies have been flattening terrain and altering drainage routes. This causes irreversible damage.
- Detailed documentation of wetlands and watersheds
We need to consider natural boundaries such as watersheds instead of governance boundaries like electoral wards for shaping a drainage plan.
- The Metropolitan Development Authorities, National Disaster Management Authority, State revenue and irrigation departments along with municipal corporations should be involved in such work together.
- Wetland policy: We need to start paying attention to the management of our wetlands by involving local communities.
- Porous building materials: Our cities are becoming increasingly impervious to water, not just because of increasing built up but also because of hard, non-porous construction material that makes the soil impervious.
To improve the city’s capacity to absorb water, bioswales and retention systems, permeable material for roads and pavement, drainage systems can be used. It will allow storm water to trickle into the ground, green roofs and harvesting systems in buildings.
- Stop the blame: Acknowledging the role of different actors for the city can create a practical space to begin this work. The constant search for a scapegoat to blame should stop.
We need to urgently rebuild our cities such that they have the sponginess to absorb and release water. Doing so will not just help control recurring floods but also respond to other fault lines, provide for water security, more green spaces, and will make the city resilient and sustainable.