Topic: General Studies 2,3:
- Urbanization, their problems and their remedies
- Government policies and interventions for development in various sectors and issues arising out of their design and implementation
Urban Floods: Time for a ‘sponge cities’ mission in India
Context: Torrential rains in the third week of October in Hyderabad during which over 50 people died and hundreds of riverbed hutments were flushed away.
The scale of destruction has been unprecedented. This experience is not unique to the city of Hyderabad but something that cities across India have been experiencing in recent years.
What are the possible reasons for Urban Floods experienced in Hyderabad?
- Unprecedented rainfall: The rainfall received in 2020 has been the highest for the month of October in a century.
- Inability to manage the city’s drainage systems: The floods of October 2020 occurred because discharge of water did not take place on time. And when water was discharged it was in a sudden, uncontrolled manner. To put it bluntly, first sluices did not open and then bunds breached.
- Antiquated drainage infrastructure: Hyderabad’s century-old drainage system (developed in the 1920s) covered only a small part of the core city. In the last 20 years, the city has grown at least four times its original built-up area and not much was done to address the absence of adequate drainage systems.
- Neglecting issues of incremental land use change, particularly of those commons which provide us with necessary ecological support — wetlands. This has led to creation of urban terrain which is incapable of absorbing, holding and discharging water.
One of the promising ideas to deal with Urban Floods is Sponge Cities
- The idea of a sponge city is to make cities more permeable so as to hold and use the water which falls upon it.
- Sponge cities absorb the rain water, which is then naturally filtered by the soil and allowed to reach urban aquifers. This allows for the extraction of water from the ground through urban or peri-urban wells.
- In built form, this implies contiguous open green spaces, interconnected waterways, and channels and ponds across neighbourhoods that can naturally detain and filter water
- 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
What steps need to be taken to take forward the idea of Sponge Cities Mission?
- Wetland policy:
- In most of our lakes, the shallow ends, which often lie beyond the full tank level, have disappeared.
- These shallow ends are best characterised as wetlands; sometimes owned by private individuals, other times existing as ecological commons.
- Regardless of ownership, land use on even this small scale needs to be regulated by development control.
- Watershed management and emergency drainage plan
- This should be clearly enunciated in policy and law.
- Urban watersheds are micro ecological drainage systems, shaped by contours of terrain.
- Detailed documentation of these Urban watersheds must be held by agencies where natural boundaries instead of governance boundaries (like wards) are used to come up with 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.
- Ban against terrain alteration
- Lasting irreversible damage has been done to the city by builders, property owners, and public agencies by flattening terrain and altering drainage routes.
- Terrain alteration needs to be strictly regulated and a ban on any further alteration of terrain needs to be introduced.
- Change in material usage
- Our cities are becoming increasingly impervious to water, not just because of increasing built up but also because of the nature of materials used (hard, non-porous construction material that makes the soil impervious).
- To improve the city’s capacity to absorb water, new porous materials and technologies must be encouraged or mandated across scales.
- Examples of these technologies are bioswales and retention systems, permeable material for roads and pavement, drainage systems which allow storm water to trickle into the ground, green roofs and harvesting systems in buildings.
- These not only reduce run-off and the load on infrastructure, but also help keep water in the city for later use.
- Involvement of other stakeholders
- Urban floods of this scale cannot be contained by the municipal authorities alone. Nor can they be dealt with by the State government.
- It can be managed with concerted and focused investments of energy and resources.
- Such investments can only be done in a mission mode organisation with active participation of civil society organisations at the metropolitan scale.
We need to urgently rebuild our cities such that they have the sponginess to absorb and release water without causing so much misery and so much damage to the most vulnerable of our citizens
Connecting the dots:
- Urban Infrastructure projects AMRUT yojana
- The smart cities project is faced with multiple challenges and ambiguities in terms of its financial model, governance and scale. Critically examine.