Strategies and approaches pertinent to public space for addressing floods

DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 STRATEGIES AND APPROACHES PERTINENT TO PUBLIC SPACE FOR ADDRESSING FLOODS An Assessment from Coastal Urban Slums in India Anubhav Goyal formaurbis LAB, CIAUD, Lisbon School of Architecture, Universidade de Lisboa, Rua Sá Nogueira, 1349-063 Lisboa, Portugal [email protected] ABSTRACT Climate change and disasters are fast emerging as the most defining challenge of the 21st century as global risk. Changes in many extreme weather and climate events have been observed and linked with human influences, including an increase in extreme high sea levels and an increase in the number of heavy precipitation events. About 70 percent of the coastlines worldwide are projected to experience sea level change within 20 percent of the global mean. India, a developing country of global south and a major global contributor, is among the first ten countries in climate risk index. The country is witnessing average sea level rise of 1.7 mm/ year with rising sea projections in coastal cities. Further, India host a large percentage of urban population living in slums. Dharavi slum, Asia's biggest slum, located in the centre of Mumbai along the coast, host a population of more than a million in just 2.1 square kilometre. Slums are located at land which is usually unsuitable for formal development, being the low lying marshy areas along the river basins or coastal mangroves. As a direct cause, the physical location of the slums in developing world, makes them at a greater risk of flooding. Urban slums of metropolitan Mumbai, Kolkata and Surat in India, along with many others, are vulnerable to flooding. The present policy framework lack in providing for climate resilience and has thus compelled the slum dwellers to adapt to the risk of flooding with local community based measures involving public space retrofits. The paper assess these adaptation measures and strategies from different coastal urban slums in India and aims to create a theoretical framework of measures and elements. Case study analysis approach is used to generate for adaptation strategies and presented in the parameters (type – time – role – intent and scale of adaptation). Results showcases a framework of adaptive and mitigation measures pertinent to local participation DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 and public space retrofits for coastal urban slums. It enables the generation of a typology, lexicon of measures and elements, a toolkit to face extreme floods. Community mobilization with public space retrofits open new possibilities for addressing future floods and in gaining resilience. Keywords: Adaptation, coping strategies, flood resilience in slums, public space retrofits. Thematic block: Public space and urban project in the contemporary metropolis. DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 1. INTRODUCTION Climate change and disasters are fast emerging as the most defining challenges as global risks with higher impacts on neglected areas of the cities. The rate of sea level rise since the mid nineteen century has been larger than the mean rate during the previous two millennia (IPCC, 2014, p.2, 4). Changes in many extreme weather and climate events have been observed since about 1950. Some of these changes have been linked to human influences, including a decrease in cold temperature extremes, an increase in warm temperature extremes, an increase in extreme high sea levels and an increase in the number of heavy precipitation events in a number of regions (IPCC, 2014, p.7). Flooding in coastal cities around the world is due to higher precipitation or sea water rise. It is the most common hazard, can be generally defined as the overflowing of the normal confines of a stream or other body of water, or the accumulation of water over areas not normally submerged. A particular flood can result from many combinations of meteorological, hydrological and human factors (Matos Silva, 2016, p.81). Flooding in urban areas is not just related to heavy rainfall and extreme climatic events; it is also related to changes in the built-up areas themselves. Urbanisation aggravates flooding by restricting where floods waters can go, by covering large parts of the ground with roofs, roads and pavements, by obstructing sections of natural channels, and by building drains that ensure that water moves to rivers more rapidly than it did under natural conditions. Such situations frequently arise where poor people build their shelters on low-lying flood plains, over swamps or above the tidewater on the coast (Unjust Waters, 2006, p.3). The impact of climate change are imposed on these people-driven local land surface modifications. The 2003 World Development Report notes the pronounced difficulties the poor face when disaster strikes. People in low-income countries are four times as likely as people in high-income countries to die in a natural disaster... Poor people and poor communities are frequently the primary victims of natural disasters, in part because they are priced out of the more disaster-proof areas and live in crowded, makeshift houses... poor families are hit particularly hard because injury, disability, and loss of life directly affect their main asset, their labour. Disasters also destroy poor households' natural, physical, and social assets, and disrupt social assistance programmes (Satterthwaite, Dodman, 2010, p.206). Further, the developing countries such as India are facing the problem of increasing urban slums. In metropolitan cities like Mumbai, the percentage of slum population is high reaching 54 percent (Census of India, 2001). Slums are located at land which is usually unsuitable for formal development, being low-lying marshy areas along the river basins or coastal mangroves. The physical location and inability to prevent and absorb excess water makes them at a greater risk of flooding. For India, tackling the challenges of climate DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 change and flooding posits particular significance as being a major global contributor. India is among the first ten countries in climate risk index of 2018. Through flood events and the response of slum dwellers suggests that adaptation measures needs more integration of local participation through vernacular coping strategies. 2. LITERATURE REVIEW India is witnessing average sea level rise of 1.7 mm/year with projection of putting 36 million Indians at risk by 2050 (Times of India, 2019). The coastal cities of Mumbai, Kolkata and Surat are victims of climate change and host a numerous urban slums along the river basins and coasts facing recurring floods. These cities are vulnerable to recurring floods due to common reasons being faulty zoning regulations and planning, flash floods, cyclones and reduction of green infrastructure and destruction of wetlands. It is no wonder that contemporary Kolkata's regular flooding, or the projected submergence of parts of Mumbai by 2050, was a century in the making (Bhattacharyya, 2020). [Fig.1 Rising sea water in coastal cities of India published in Times of India, November, 2019. Derived from https://timesofindia.indiatimes.com/india/india-witnessing-average-sea-level-rise-of-1-7mm/year/articleshow/72134279.cms and https://timesofindia.indiatimes.com/india/rising-sea-may-put-36-million-indians-at-risk-by-2050/articleshow/71834444.cms] 2.1 THE CASE OF MUMBAI Mumbai was originally an archipelago of seven islands. Bombay, the old name of the city, meaning good bay, expresses a deep connection between the city and the water, built on the foundation of continuously altered and reclaimed natural and urban landscapes, an outcome of colonial exploitation, geo-political agendas and DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 global competitiveness. Mumbai is a sanctuary for immigrants and urban slums forms a significant element of urban landscape. “Throughout the making of Mumbai, reclamation – in the sense of land creation, recovery, repossession, renovation and recuperation – has been (and remains) the driver of states of change” (Shannon, 2009, p.9). Slum settlements house approximately 55 percent of Mumbai's population and are mostly located in low lying areas close to marshes and other marginal places (O'Hare et al. 1998). These slums are frequently flooded during monsoon season. Formal flood mitigation strategies adopted by the city authorities do not reduce risks for people living in informal settlements (Chatterjee, 2010, p.344). This compelled the local slum dwellers to adopt vernacular adaptation strategies. The heaviest rain was seen on 26th of July, 2005. Floods in Mumbai are said to be caused by heavy rains accompanied with high tides (Kadave et al. 2016, p.224). [Fig.2 High tide hits the shore in Mumbai published in Times of India, High tide alert: Mumbaikars warned against venturing near sea, June, 2013 derived from https://timesofindia.indiatimes.com/city/mumbai/High-tide-alert-Mumbaikarswarned-against-venturing-near-sea/articleshow/36484560.cms] The database of flood instances between the year 2000 and 2008 shows an average of 76 instances of flooding annually in the island city (Mumbai - District), 57 instances in the Eastern suburbs and 129 flooding instances in the Western suburbs. Historically, Mumbai has been receiving an annual rainfall of about 220 cm during the monsoon season between June and September. Since 2004, the average annual rainfall has been more than 240 cm. Heavy precipitation and resultant flash floods are regular event in Mumbai (Patankar, 2015). The reasons for flooding in Mumbai are extracted and listed in table - 1. The primary reason of flooded water logged areas in Mumbai stems from the reclamation between the original seven separate islands as DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 illustrated in Fig.3. Flooding happens where the drainage both man-made and natural are insufficient and clogged. There are many slums and MHADA sites around the Mithi River and Mahim creek that at high risk of flooding. “The strong setting places Mumbai in a category of large cities which have a particular relationship to landscape – similar in a certain sense to places such as Rio de Janeiro, Hong Kong, Cape Town and Barcelona. Nature and urbanity are in extremely close proximity, with both spectacular and problematic results” (Shannon, 2009, p.58). [Fig. 3 Hydrographic Map of Mumbai: Water logged reclaimed areas between the original seven separate islands. Dharavi slum encircled. Derived from http://mapsof.net/uploads/static-maps/hydrographic_map_of_mumbai.jpg] Further, the drainage system of Mumbai was constructed to handle rainfall at the rate of 25mm/hour. The city is actually subjected to approximately 100mm/hour which already stretches the existing capacity (Dharavi weekly, 2020). Further, encroachments and building on the city's natural drain has resulted in a catastrophic DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 scenario. The storm water drainage for Mithi River catchment area has been disrupted due to the encroachment of hutments in large numbers, storage facilities, processing industries, workshops and other scrap yards situated along the banks that make it difficult to even delineate its path (NEERI, 2011). Lack of waste management resulting into clogged drains exacerbate flooding. The average depth of flooding in the surrounding compound, as reported by the households, is about 1.5 feet with the range of 0.5-4.5 feet and water remains between 0.5 to 8 hours depending on the area. 42% of the households have reported that flood waters enter their house every year during monsoon (Patankar, 2015, p.18). [Fig.4 Mithi River along Dharavi slum in Mumbai published in The Wire, As Mumbai Rains Wreak Havoc: Slum Dwellers the Worst Affected, July, 2018 derived from https://thewire.in/government/as-mumbai-rains-wreck-havoc-slum-dwellers-the-worst-affected] DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 [Fig.5 Mithi River along Dharavi slum in Mumbai published in DNA, Mumbai: BMC to pump big money on sewage, February, 2019 derived from https://www.dnaindia.com/mumbai/report-mumbai-bmc-to-pump-big-money-on-sewage-2718507] [Fig.6 Choked drain in Mumbai published in Outlook India, September, 2014 derived from https://www.outlookindia.com/photos/single/96872] DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 [Fig.7 Reclamation at Mithi River bank by BMC for metro project resulting in reduction of river width published in The Asian Age, December, 2017 derived from https://www.asianage.com/metros/mumbai/181217/activists-warn-of-flooding-due-to-mithi-width-cut.html] Climate change adaptation is a learning continuous adjustment process aimed at reducing vulnerabilities (Matos Silva, 2016, p.59) and the response of slum dwellers towards flooding is considered significant in generating coping strategies and adaptation measures. Throughout history, people and societies have adjusted to and coped with climate, climate variability and extremes, with varying degrees of success (IPCC, 2014, p.54). Living in harmony with water and vernacular adaptation has become a requisite in slum neighbourhoods. Chatterjee discussed the response of slum dwellers and learnings from flood event in 2005. It is observed (Chatterjee, 2010) that formal flood mitigation and adaptation strategies adopted by city authorities do not reduce the risks for urban poor. Neither relocation of urban slums is the solution due to strong network of livelihoods and social organization. Slum dwellers do whatever little they could to deal with the intensity of the monsoons. This includes using of plastic sheets to cover windows and over the roofs or relocation to safe higher floors. Furthermore, the raising of the floors and the veranda can help prepare for the monsoon rains. With the limited ability, the households, both poor and non-poor, undertake various measures every year on the onset of monsoon through their own initiative and funding (Patankar, 2015, p. 21). Furthermore, cleaning house surroundings, canals, sewer drains and repairing roofs are most common recurrent measures. Women in Versova's urban fishing village spread risk by using insurance, engaging in community-based fishing, and diversifying their livelihoods in the face of growing coastal erosion (Banti et al. 2016). Mumbai lacks sectoral or city-scale planned adaptation projects or policies. While the city has a coastal DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 Table 1. Description of flood adaptation parameters. Derived from previous established classification in scope of this paper. Parameters Categorization Description Type Infrastructural Infrastructural measures involve coverage of basic physical infrastructure such as sewer lines, water channels, drains, green permeable spaces etc. Also include re-structuring and improving the aging infrastructure or waste landscapes. Such measures are adopted at all scales. Behavioral Such measures depend on individual or community choices. Ecological These are eco-system based measures. Typically natural soft measures of protection. Institutional Involve formal mandate in long term climate change mitigation and adaptation planning in form of action plans fragmented in different agencies and programs. Scale Individual Measures adopted at household level. These primarily depend upon behavioral factor and individual capability to adapt. Such measures plays vital role in risk reduction for urban slum dwellers. Neighborhood These measures provide for risk reduction at community level. Slum settlements hold inviolable social networks and measures with local community level participation are vital in risk reduction for urban slums. City Formal government action plans and interventions largely provide for adaptation measures at city level. Time Reactive These are autonomous actions that evolve as circumstances change during a flood event Anticipatory These measures are performed and based upon the presumption of a future flooding event in time and magnitude. The anticipation of an event can be in long term projections or short term. Concurrent These measures are performed on continuous regular basis irrespective of the flood event. Role Defend The protection strategy is based upon defending (protecting from) the impacts of flooding. Engage This involve the water with measures and elements to live in harmony with water resulting in risk reduction. Store Such measures and elements entail the infrastructural capacity to store water and also provide for reduction in surface runoff. The storage mechanism/ infrastructure can be over (open/ closed) or below the ground surface. The stored water can be filtered, cleaned and transfer back for other purposes. Intent Autonomous Autonomous measures are individual independent measures based on behavior and desire/ necessity towards flood adaptation. Such measures are not imposed from formal government action plans. Strategic/ Planned Strategic/ Planned measures and elements are imposed and enforced as action plans resulting from long term strategic assessment. The intent of desire and freedom is absent. DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 Table 2. Framework of measures and elements for flood adaptation. Derived from case examples. DOI: 10.5821/siiu.10153 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 DOI: 10.5821/siiu.10129 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 4. RESULTS AND CONCLUSIONS The impact of climate change are aggravated in urban coastal cities which is evident from the recent flood events in the assessed cities. The paper examines the adaptation measures and elements pertinent to physical public space for urban slums in three mega-cities in India. Very little has been done in regard to research and systematization of vernacular measures by urban poor. Formal measures provide less towards the risk and vulnerability of urban poor and in developing countries with higher percentage of slums, addressing floods depend on the ability of slum dweller to respond, physical factors such as protection from water leakages, efficiency of drainage systems and natural typological situations. The excess of water seen as a treat, is progressively being seen as an opportunity with learning how to live in constant adaptation. Adaptation at local level from slum dwellers is very crucial in the present scenario due to multiply causes and impacts of flooding. Reducing the risk and vulnerability depends on the water management in the river catchment area. It is observed, most adaptation projects and measures focused on water sector with infrastructural or institutional interventions. Only few considered interventions with nature-based solutions. Present adaptation actions are often reactive, sectoral, and risk-focused (C. Singh et al. 2021) and does not address the risk and vulnerability for slum settlements. Also, the adaptation measures varies in accordance with the geographic locations and regional identity of urban slums. The high application of bamboo in constructing defence barriers, raised platforms etc. is observed in the case of Kolkata whereas slums in Mumbai comprises strong community networks that provide for behavioural and institutional adaptation. A more visionary and multidisciplinary approach for flood resilience with potential of urban green spaces, restoring blue and green infrastructure would be acknowledging the risk and vulnerability for urban slums. For instance, urban aquaculture is under-utilized measure, which provide for mitigation adaptation benefits. The framework of adaptation measures grounds for the composition of a systematized lexicon to render urban slums resilient to future floods. Though this assessment composed of only three cities, the study can be representative of other Indian coastal cities with similar environmental and demographic settings. ACKNOWLEDGEMENT The author would like to acknowledge the support provided by the Research Centre for Architecture, Urbanism and Design, CIAUD at Lisbon school of Architecture, University of Lisbon in development of this research paper. The support and guidance from professor Maria Cabral Matos Silva Aires Pereira at URBinLAB and professor Sérgio dos Santos Barreiros Proença at formaurbis LAB with CIAUD is overwhelming and necessary towards the on-going research. Also, I recognise the suggestions from Joana de Mesquita Lima at URBinLAB which aided the development of this paper. DOI: 10.5821/siiu.10129 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 REFERENCES Abbott, Dina, Barke, Michael, O’ Hare, Greg, A review of slum housing policies in Mumbai, Cities, vol. 15, no.4, 1998, pp. 269-283. Agnihotri, P.G., Patel J.N., Study of flood at Surat city and its remedial measures the 3rd IASME In: WSEAS International conference on water resources, hydraulics and hydrology, Vol. 3, 2008, pp. 23-25. Banti, D., Krishnan, M., Ananthan, P.S., Debnath, B., Awareness, perceptions and adaptation strategies of women in urban fishing village in a climate change environment - A case study in Versova, Mumbai, Indian J. Fish. 63, 2016, pp. 120-125. Bhat, G.K., Karanth, Anup, Dashora, Lalit, Rajasekar, Umamaheshwaran, Addressing flooding in the city of Surat beyond its boundaries, International Institute for Environment and Development, Sage publications, Environment and Urbanization, Vol. 25(2), 2013, pp. 429-441. http://doi.org/10.1177/0956247813495002 Bhattacharyya, Debjani, Monsoon Planning: The Future of India's Sinking Cities, India in Transition, Center for the Advanced Study of India, Univerisity of Pennsylvania, September 28, 2020. http://casi.sas.upenn.edu/iit/debjanibhattacharyya C. Singh, M. Madhavan, J. Arvind et al., Climate change adaptation in Indian Cities: A review of existing actions and spaces for triple wins, Urban Climate 36, 2021. http://doi.org/10.1016/j.uclim.2021.100783 Census of India 2011, District Census Handbook Mumbai, Maharashtra, Directorate of Census Operations Maharashtra, Series 28 Part XII-B, 2011. Census of India 2011, Slum Population in Million Plus Cities, Office of the Registrar General & Census Commissioner, India, Ministry of Home Affairs, Government of India. https://censusindia.gov.in/Tables_Published/Admin_Units/Admin_links/slum2.html Chatterjee, Monalisa, Resilient Flood Loss Response Systems for Vulnerable Populations in Mumbai: A Neglected Alternative, The State University of New Jersey, October 2010. Chatterjee, Monalisa, Slum dwellers response to flooding events in the megacities of India, Springer Science + Business Media B V, 2010. Dasgupta, S., Gosain, A.K., Rao, S., Roy, S., Sarraf, M., A megacity in a changing climate: the case of Kolkata, Climate Change 116, 2013, pp. 747-766. Dharavi weekly - water city, Water everywhere - but not when you need it, Urbz, August, 2020. http://urbz.net Dodman, David + Satterthwaite, David, Adapting cities to climate change: Understanding and addressing the development challenges, Earthscan, London, 2010, p.206. Jariwala, R.C., Samtani, B.K., The estimation of flood and its control by section modification in Mithi and Kankara tributaries at Surat, Int. J Eng Res Appl 2, 2012, pp. 862-867. Kadave P T, Kale A D, Shubham Narwade, Mumbai Floods, Reasons and Solutions, International Journal of Scientific and Research Publications, vol. 6, no. 3, March 2016. Kirtane, Gautam, Making the sewer a river again: Why Mumbai must reclaim its Mithi, Observer Research Foundation Mumbai, 2010. Matos Silva, Maria, Public Space design for flooding: Facing the challenges presented by climate change adaptation, Universitat de Barcelona, September, 2016. Murphey, R., The city in the swamp: aspects of the site and early growth of Calcutta, Geogr J 130, 1964, pp. 241-256. NEERI (National Environmental Engineering Research Institute), Current status of Mithi River and possible solutions, NEERI, Nagpur, 2011. DOI: 10.5821/siiu.10129 SIIUXIII This work is licensed under a Creative Commons License CC BY-NC-ND 4.0 Orff, K. et al. Water Urbanism: Kolkata, Global Cities & Climate Change Studio, Columbia, GSAPP, 2017. https://www.arch.columbia.edu/books/reader/195-water-urbanism-kolkata Pachauri, Rajendra + Meyer, Leo (eds.), IPCC, Climate change 2014: Synthesis report. Contribution of working groups I, II and III to the fifth assessment report of the Intergovernmental Panel on climate change, IPCC, Geneva, Switzerland, 2014. Patankar, Archana, The exposure, vulnerability and ability to respond of poor households to recurrent floods in Mumbai, Shock waves: Managing the impacts of climate change on poverty, Policy research working paper 7481, World Bank Group, November 2015. Patel, D.P., Ramirez, J.A., Srivastava, P.K. et al. Assessment of flood inundation mapping of Surat city by coupled 1D/2D hydrodynamic modeling: a case application of the new HEC-RAS 5, Nat Hazards 89, 2017, pp. 93-130. http://doi.org/10.1007/s11069-017-2956-6 Rietveld, L.C., Siri, J.G., Chakravarty, I. et al. Improving health in cities through systems approaches for urban water management. Environ Health 15, S31, 2016. https://doi.org/10.1186/s12940-016-0107-2 Rumbach, A., Do new towns increase disaster risk? Evidence from Kolkata, India, Habitat Int. 43, 2014, pp. 117-124. Sekovski I, Newton A, Dennison WC, Megacities in the coastal zone: using a driver-pressure-state-impactresponse framework to address complex environmental problems, Estuar Coast Shelf Sci, 96, 2012, p. 4859. Shannon, Kelly + Gosseye, Janina (eds), Reclaiming the Urbanism of Mumbai, Issue 03, Sun Academia, 2009. Sharma, S.K., Chauhan, R., Climate change research initiative: Indian network for climate change assessment, Curr. Sci. 101, 2011, pp. 308-311. Tapi Riverfront Development and Rejuvenation Project, Final Concept Master Plan Report, Surat Municipal Corporation, HCP Design, Planning & Management Pvt. Ltd., October, 2019. Unjust Waters, Climate change, flooding and the protection of poor urban communities: experiences from six African cities, Action Aid International, 2006. http://actionaid.org/