India’s urban floods: Why we need to look at nature-based solutions
Extensive and recurring waterlogging and floods disrupt life in Indian cities almost every monsoon. At other times, sudden but high-intensity cloudbursts generate substantial run-off from the city’s concrete surfaces that inundate low-lying locales.
To combat such occurrences, to date, cities have mostly relied on traditional approaches of flood management termed ‘Grey Infrastructure’. These often get overwhelmed during heavy downpours due to the reduced capacity of installed pipelines, flood storage, drawbacks in the operation of pumping stations and a general lack of maintenance.
Many older Indian cities do not even possess a proper urban stormwater management system. However, several cities worldwide have devised sustainable water adaptive urban designs, keeping in mind Goal 13 of United Nations-mandated sustainable development goals: Climate Action.
These nature-based solutions are socio-ecologically sound to reduce the loss of lives and livelihoods from urban floods. These measures can be exercised at both ends of the system, from individuals in households to local government bodies.
Though such practices do not have a universally accepted definition, they usually include setting up components like urban forests, terraces and slopes, open green spaces and corridors.
Some other components are urban farming and bio-retention areas, natural or constructed inland wetlands, river and floodplain restoration, riparian buffer formation or rejuvenating and installing mangroves and salt marshes, based on space availability and the nature of the ambient topography, city site and size and its socio-economic profile.
However, some questions that often come to the fore are whether NBS actually works and does it really have viable benefits over grey infrastructure. These queries are examined from a few bases.
Grey Infrastructure vs. Nature Based Infrastructure (NBS)
| Sl No. | Bases | Grey Infrastructure | Nature Based Infrastructure |
| 1. | Knowledge of planning and engineering required | At a huge scale, with substantial technical expertise | At a comparatively lesser extent |
| 2. | Space needed | Large space(s) required | Though space is the ultimate problem in urban areas, but still, it can be setup at the micro-scale, if desired (urban roof tops) |
| 3. | Cost involved | Expensive for setting up, maintaining and upgradation | Cost effective, multi-purposive |
| 4. | Flexibility | Less flexible | Apt for the ever-expanding urban areas |
| 5. | Environmental impact | Detrimental to the ecosystem | Clean technology that benefits ecosystems in the longer term |
| 6. | Contribution to carbon emission and energy consumption | Right from the first stage of building the structures (e.g., dams) to throughout its existence | Nil, rather it enhances carbon sequestration via the installed green cover |
| 7. | Point/non-point measures | Brings catastrophe if single point failure happens | Non-point solution, thus generates a sustained impact on local climate change |
| 8. | Local community involvement | Least | Far greater and is the most among all the approaches of urban flood mitigation |
| 9. | Comprehension by all | Generates a myth about protection against climate driven disasters | Easy to follow, even for people with no knowledge of urban flooding |
Involvement of different stakeholders in the NBS network along with the parameters usually considered by city-planners while devising strategies for urban flooding
In India, unrestricted and haphazard urban sprawl has been a dominant phenomenon in cities of Jammu and Kashmir, Rajasthan, Gujarat, Maharashtra, Chhattisgarh, Karnataka, Tamil Nadu, West Bengal and Assam.
These cities often expand without considering how many waterbodies are lost within the city boundary and along the peri-urban zone, thus exacerbating future urban flooding issues.
However, some adoptions of the NBS approach have been formulated across the country by involving local communities in different Tier-I, II and III cities, which are listed below:
- Mumbai: A sustainability drive called The City Fix Lab: Accelerating Nature Based Solutions addresses acute urban issues such as water availability, floods, heat waves, air pollution and urban greenery loss by involving citizens and local action groups.
The Climate-Proof Cities: India movement, which involves eminent scientists, has been trying to resurrect the Powai and Banganga lakes in terms of their ecological attributes. - Bengaluru: Studies have highlighted the detrimental effects of land use change on urban drainage, especially the increasing proportion of built-up area and the loss of green buffer zones within and around the city.
- Efforts to rejuvenate Puttenahalli Lake and create an ‘Urban Jungle’ for the city and enhance its biodiversity have been ongoing.
Read more: Urban floods: lessons from Jammu & Kashmir
- Surat: Situated near the coast and along the lower stretch of the Tapi River, this important business hub is not only susceptible to fluvial floods and pluvial waterlogging but also gets inundated by tidal ingress.
- Gorakhpur: The city has set an example of its own kind with comparative low-budget and easy-tech nature-based solutions that involve its citizens.
The existing and proposed land use in urban flood prone cities (as per the framed master plans and at a gap of 20 years from the base year) on top. The existing and proposed percentage of recreation area/open space to total area and the same proportion 20 years later. Source: Computed based on Urban Green Guidelines, 2014, TCPO, GoI, MoUD
States like Jammu and Kashmir have opted for eco-restoration policies to fight against climate change. Guwahati has emphasised the importance of open spaces within built-up areas, preservation of watersheds and wetlands, reconnecting the floodplains and afforestation.
Some notable NBS-based efforts to combat urban drainage issues and environmental impacts are Bhopal’s green-blue smart city plan, Delhi’s Master Plan 2041, Chennai’s water as leverage initiative and Pune’s urban agricultural plan.
The continued urban growth of Kolkata has seriously threatened its biggest carbon sinks and natural water retention and drainage zones, the East Kolkata Wetlands and the Rabindra Sarovar.
Many a project funded by the United Nations and the Asian Development Bank, in collaboration with the Kolkata Metropolitan Development Authority, has focused on urban greening, maintaining open spaces and preservation of wetland and waterbodies.
Yet much more remains to be done, given the continued sprawl of the city, the emergence of newer urban centres adjacent to it and the sustained transformation of wetlands to built tracts.
A long way to go
India’s disaster risk reduction policies have usually considered natural assets. However, issues like equal stakeholder participation and shared responsibility among policy shareholders are myths, even where NBS solutions are being implemented.
Miscoordination at various level of planning have often stymied the efficacy and economic viability of NSBs, with more immediate (and high cost) structural measures being pushed through instead of favouring a longer-term, ecologically friendly, community-based cost-effective approach, in combination with already existing built measures.
However, India’s urban population is expected to reach 814 million by 2050, with the addition of four new megacities by 2030. So, there is an urgent need to recognise and advocate the adoption of NBS to mitigate urban flooding and include them as crucial components of city master plans and urban renewal schemes.
The major focus areas of such an NSB-based urban flood mitigation plan would be:
A feasible NBS based urban flood mitigating framework
Nature Based Solutions may not provide immediate benefits but are garnered towards yielding greater long-term sustainable advantages in combating fallouts from the ongoing climate crisis.
The inclusion of NBS in disaster and risk reduction policy frameworks has yet to occur substantially in India, even though there are a few missions and action plans that are explicitly comprised of some facets of eco-based resilience.
Some ecosystem-based disaster risk reduction policies in India are: National Mission for Sustainable Habitat, 2007, National Water Mission, 2008 and National Mission for Green India, 2010 under the National Action Plan for Climate Change, 2008.
Intended Nationally Determined Contributions presented by India to the United Nations Framework Convention on Climate Change in 2015 for lowering the nation’s GHG emissions is one more such example.
The central government in India has also launched urban development-specific schemes wherein stormwater drain management and encroachments are addressed. Examples of some of them are the Atal Mission for Rejuvenation and Urban Transformation, Smart Cities Mission and the Swachh Bharat Mission.
On the other hand, corporate houses have also already shown interest in the carbon-offset sector, with promising and increasing investments. NGOs like India Climate Collaborative and the Center for Science and Environment are engaged in creating greater awareness of NBS issues and mobilising plans and resources for their implementation.
Views expressed are the author’s own and don’t necessarily reflect those of Down To Earth