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Tanks & Berms: Estuary as Resilience Engine

This project adapts a home-grown system of tanks and berms developed by coastal slum residents to address water contamination and flooding.

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The dynamics of informal settlements the world over generate social and ecological networks that can be progressively transformed both to make these settlements more resilient and to create more sustainable urban change for the cities of which they are a part. Communities in these settlements are not only formed by histories of sharing cultural practices, linguistic, regional and ethnic origins but also by sharing environmental risks and claims-making vehicles. We wish to enhance resilience by improving socially generated infrastructure and empowering communities to share in mitigating the effects of climate change. Our project focuses on one informal urban ecosystem, a home grown system of tanks and berms cultivated by the Koli fishing community occupying the northwestern edge of Dharavi - an informal industrial settlement in Mumbai who use the tanks for fishing and the berms for community gardening. We propose to redesign and retrofit this system, multiplying its functions and effects. Our project empowers the Koli elders who are the stewards of these tanks and berms to upgrade this infrastructure by retrofitting the tanks to address water contamination issues; slow storm surges; capture and control release of tidal and sea level rise flooding; capture waste for recycling and energy generation through wave action within the tanks. Thus converted, the system of tanks and berms could serve the city as a whole to become resilient to the effects of climate change.


The Koli community gains stewardship by transforming its infrastructure into a system for cleansing and flood control. Residents working with adjacent recycling clusters gain access to systemically filtered recycling waste. Adjacent land owners gain income through leasing fees and direct power supply from energy production. The municipal corporation, sediment purchasers and treatment firms benefit through purchasing agreements. Mumbai residents gain a coastal buffer and cleaner groundwater.


Our long-term, ethnographic research identifies small-scale and home-grown infrastructures that are a signature of informal settlements all over the world. Our approach advocates designing within the existing ecosystems created by these infrastructures thereby designing projects that are consonant with the social and political strengths of the community. Because the design leverages and scales up these home-grown systems of affordances to generate livelihoods as well as to hedge against various environmental risks, our project could take root and succeed in becoming a practical demonstration of alternative resilience strategies to the city. It demonstrates practically how climate change mitigation techniques and informal infrastructure-making could intertwine to produce advantages for all urban residents. In terms of technology, our retrofit of the system of tanks and berms extends their functions to add waste capture, flood control, energy generation, water treatment and sediment conversion simultaneously. Thus it creates new beneficiaries and stakeholders in the system. If successful, it has potential benefits for the city of Mumbai as a whole, providing an alternate vision of development for other informal settlements along the coast as well as a model and method for coastal cities elsewhere in the world, enhancing resilience through social participation in infrastructure-making.


  • Yes, for two or more years


  • I’ve worked in a sector related to my idea for at least two years


  • Yes


We are an independent, interdisciplinary not-for-profit research and design group with expertise in anthropology, landscape architecture, urban planning and data visualization. Our method combines ethnography and visualization to identify local solutions to combat vulnerability and inequality.


This idea was first developed during fieldwork in Dharavi in 2014 as part of a larger investigation into the speculative strategies used by slum residents to address precarity in Mumbai. The objective of our research has always been to sketch alternative scenarios towards more just and equitable cities. But our focus on climate change resilience as such is new. The Koli community introduced us to their tank and berm system and we began to link its ecological value to the city as a whole. We have been developing this idea with feedback from the community but have not begun testing it.


Urban slums are generally viewed as obstructions to natural ecosystems and are thus viewed as an integral part of the problem that cities face in adapting to climate change. Our initiative turns this logic on its head by understanding the systems of affordances that slum residents have painstakingly designed and improved upon over time as part of the solution to climate change resilience. Rather than turning to mega-scale engineering projects such as sea walls, we suggest upgrades to a system of networked micro-solutions among which the “Tanks and Berms” project is an initial pilot study. We envisage not only protecting ecological assets locally but creating a new imaginary of slums and their capacities for the city as a whole. With this project, we also garner support from additional stakeholders at the local level, thus enabling connections between different groups within large, heterogeneous settlements such as Dharavi.


In Mumbai, various policies have reduced slums to a housing problem. Their value to the city is calculated in terms of the potential for real estate surpluses through slum redevelopment projects. Our project is based on transferring this potential value from real estate to the ecological and economic value generated by slums in stewarding the urban ecosystems that they occupy. But this transferral requires a new legal and policy framework to enable community land and infrastructure trusts as vehicles for implementing multiple projects similar to the one we propose. Our project calls attention to this fundamental yet unanswered question while demonstrating a path forwards.


The imaginary of the slum as a housing problem has dominated the field of urban development for several decades. Our project aims at introducing a new imaginary, based on designing within the transformed ecosystem and scaling up the bottom-up tactics that have been systematically introduced and shepherded by vulnerable communities. By moving away from strategies that call for the erasure and replacement of slum settlements we advocate for an approach that places economic and ecological value generated by these communities at the center of our design. We believe that the problem that our project designs around has not yet been imagined as a problem let alone being solved.


Following initial research into the tank and berm system, key tank stewards from the Koli community have provided insight into the history of environmental contamination, their livelihood practices, and community relations in Mumbai. Their feedback following each design iteration has focused the project’s core components to interventions that address their own concerns with environmental contamination and interventions that will maintain their security of land tenure. In the coming months, we will work together to develop collective governance structures, including a community infrastructure trust, to provide decision-making and coordination of incremental upgrades to their existing infrastructure. Beneficiary feedback has also directed us to develop the project in ways that resonate with other community groups across the city who seek similar interventions through collective governance structures.


Our broader goal is to test out a new platform where academic research, community-based design research and prototyping come together meaningfully and enhance the impact of the solutions developed by communities. To achieve this idea, we need a process to present this idea simultaneously to policy stakeholders who rarely, if ever, meet together on these challenges. We also need to work with financial engineers on the feasibility of offering infrastructure trusts with local communities as primary stakeholders as investment vehicles. Our dream is to define a new process for connecting slums economically and ecologically to the cities of which they are already a vital part.

How does your idea connect to the broader system of the city where you plan to implement?


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Photo of Chioma Ume

Hello Spatial Ethnography Team! 
Below is some feedback from our experts. We're looking forward to reading your responses!

This could be an exciting idea - it could make a big difference to the ecosystem and resilience of the area.

What about the legal right to alter flows in this way - is this going to be possible ? There needs to be a clear business plan - what are the rates of return - would there need to be an ongoing subsidy - would this be justified for the flood prevention? How will you decide the design parameters - against what size flood / storm surge? How would the system alter power/social dynamics as it becomes a higher investment / higher return activity?

Photo of Spatial Ethnography Lab & Terreform

@Chioma Ume

Dharavi Koliwada is a part of the dynamic, industrial settlement of Dharavi. Incrementally developed since the early 20th century, Dharavi encompasses several industrial clusters dealing with plastic, metal and glass recycling, textile and leather manufacture, food production and pottery along with several other specialized industries such as surgical suture manufacture and crafts associated with seasonal religious festivals. Since 2004, the settlement has been designated as a special planning zone under the supervision of the Dharavi Redevelopment Project (DRP), a state government body charged with drawing plans for the redevelopment of the neighborhood as a whole. Surveying associated with the DRP establishes land ownership and property rights as well as appropriate compensation criteria for slum dwellers who must be moved so that the entire 550 acre locality can be redeveloped as a whole.

Dharavi Koliwada is not officially a part of the DRP though it is adjacent to the DRP planning area. Its residents are protected from displacement both as a protected tribal community and as residents of an urban village having special development rules. The DRP plans will inevitably affect both the Koliwada as well as the portions of the wetlands that are occupied by the tanks as they introduce massive amounts of new construction activity and new patterns of settlement within the territory of Dharavi. However the DRP is solely focused on the development of land for residential and commercial purposes - its plans do not extent to adjacent wetlands. Those wetlands come under various competing city and state bureaucracies.

The tanks and berms that form the focus of this project are protected within a legal exception. Their control rests with the Koli community whose stewardship is protected under a grandfathered legal clause that safeguards their cultivation rights over the tanks. These rights do not preclude, inter alia, the alteration of flows within and around the tanks as needed to support fish farming. This project exploits the loophole that provides control over the tanks to the Koli community, both to alter the dynamics of flows within the tanks and also to expand the tanks’ functions. Feedback from the community suggests that tank-based water treatment and the dredging of nightsoil deposits will directly benefit fish farming and that those activities will come directly within the purview of the tanks’ present functions. Dredging activities will deepen holding capacity within the legal boundaries of the tanks without directly altering the flow of water in the municipally controlled channels outside. Thus these activities will have the dual function of supporting Koli livelihoods whilst cleaning and altering the ecology of the tanks and the mangrove forests within which they are situated.

Our research over the last decade has indicated that cities like Mumbai have specific cultures of change - change is stealthy and exploits loopholes rather than taking place through planned policy pathways. Policies often follow in the wake of stealthy prototypes that demonstrate the capacity for positive transformation. Our project reflects this culture of change both in its form and its practice. The project depends on the civic activism of the Kolis themselves and is modeled along the lines of other civic initiatives such as the NGO SAVE (Save Andheri-Versova Enviroment Forum), which is dedicated to rebuilding the mangrove forests through replanting campaigns and by monitoring enchroachment along the Andheri-Versova waterfront in North-West Mumbai. Their tactics populate the wetlands with public activities that then prevent builders and developers from cutting the mangrove trees, filling the water with debris, and creating additional land for construction. The tanks and berms project also follows this model for altering flows - it is legally safeguarded through the rights of the Koli community over the parts of the wetlands occupied by the tanks as well as providing a stage for the community to demonstrate the city-wide benefits of activities associated with their livelihoods.

Photo of Spatial Ethnography Lab & Terreform

Chioma Ume 
The tanks are adjacent to Dharavi’s waste-to-factory industrial clusters. These clusters upcycle salvaged plastics, metals, and glass into regional and global market regimes and use the wetlands as dumping grounds for heavy metals and chemical runoff. The project’s business plan is incremental and builds upon the concept of infrastructure trusts that are based on the ‘impact investing’ of philantrocapitalism that informs new legal regulations governing Corporate Social Responsibility in India.

1. We would initially seek small grants from the informal industrial associations within Dharavi and seek matching CSR funds to support dredging activities and water treatment using vegetal remediation techniques.

2. Sale of dredged materials - including recyclables to the industrial associations and nightsoil to fertilizer manufacturers – who would then continue to support these activities.

3. In the third phase we will begin to generate wave energy and use that to increase water treatment capacity.

4. In the next phase we will seek to set up an infrastructure trust including the Koli community and local entrepreneurs as well as corporate investors to create a sustainable fund of subsidies for the expanded activities around the tanks.

5. Additional income generated from pisciculture and agriculture as well as from sale of materials will continue to sustain the activities around the tanks even as their impact on flood prevention and climate resilience becomes demonstrable over a five year cycle.

On 26 July 2005, record flooding of 34 mm rainfall per hour over 24 hours overwhelmed the municipal storm water drainage capacity of 25mm per hour. With heightened berms, the existing tanks could hold a combined 89,230 cubic meters of water for slow release during storm surge events. Infrastructural upgradations can be facilitated by technical experts under the guidance of the infrastructure trust.

We envision this project as a prototype whose demonstrable success could alter the imaginary around latent opportunities in Mumbai’s resilience to climate change. We can only speculate on how the social dynamics and the dynamics around power might change over time with such project. The most important change might be in the making visible the role of poor communities and their ongoing stewardship of resources crucial to the city as a whole. Secondly, this project may also impact the plans for Dharavi’s redevelopment, requiring the state to consider ecological services and the livelihoods of residents as part and parcel of the plans for the area as a whole. Thus far, the DRP is focused on land and property creation, with little thought for the potential role of the wetlands. We believe that increased construction in this vulnerable area will be a disaster for the city as a whole. The prototype we are developing, on the other hand, might suggest other ways of transforming Dharavi, not as a land bank but rather as an infrastructure bank for the city as a whole. We believe that the tanks and berms project has limited potential for becoming a high investment/high return activity. Its impact is rather on the imagination around resources and an alternative economy based on energy, artfulness, entrepreneurship and the creative stewardship of ecological and man-made resources as infrastructure. Since Dharavi’s social dynamics are already poised for change through the DRP plans which will eliminate much of the neighborhood’s industrial activities in the near future, we believe this is the right time to initiate this project’s five year prototype to pave the way for synergies between the development of land and the development of the adjacent wetlands.

Photo of Chioma Ume

Thanks for this detailed response! Who do you expect would initially work on the berms? Would it be your organization? People who live in Dharavi? Cooperation with another NGO? Happy New Year!

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