Urban Floods in Kerala: Integrating Climate Uncertainties into Planning and Governance for a Resilient Future
The Arabian Sea is warming faster than other parts of the Indian Ocean. This increase in temperature is causing more frequent and intense weather events, like cyclones and heavy rains, particularly affecting the Kerala coast. In May 2024, a depression in the Arabian Sea led to severe flooding in many cities in Kerala. This article examines not just the role of climate change in these events, but also how rapid urbanisation contributes to the problem, exacerbating the effects of extreme weather and leading to urban flooding.
Flooding vs. Urban Flooding: Unraveling the Key Differences
We’re all familiar with conventional floods—those where rivers overflow their banks following substantial rainfall in their catchment areas, like the 2018 flood in Kerala. These types of floods can often be managed with engineering solutions such as drainage systems and dams, thanks to their predictability based on rainfall intensity and topography.
However, urban flooding presents a newer, less understood challenge. Occurring mainly in urban environments as a direct consequence of urbanization, urban floods arise when heavy rains overwhelm the drainage capacity, leading to waterlogged streets and neighborhoods. Unlike riverine floods, the occurrence of urban floods is difficult to predict. Even when heavy rain is forecasted, it’s hard to pinpoint exactly where, how, and to what extent the flooding will manifest. Often, the true scale of the threat only becomes apparent after the event, once the damage has been done.
The unpredictability of urban flooding stems not just from topography or proximity to water bodies, but from a myriad of complex factors. What makes urban flooding particularly perilous is not solely the volume of water, but rather its impact on densely populated urban settings. Even with relatively lower volumes of water, the potential for widespread disruption is significant, affecting countless individuals and disrupting essential systems. The repercussions can range from electrical hazards due to downed power lines, to vehicular accidents, fallen trees, and even the spread of diseases.
Urban Development and Climate Change: Unpacking the Causes of Urban Flooding
Urban flooding is a multifaceted phenomenon shaped by both meteorological factors and urban infrastructure. At the heart of this issue are atmospheric conditions, particularly heavy and unexpected rainfall events, which can inundate cities with water in a short span of time. These intense rainfall episodes are closely linked to climate change, which is believed to exacerbate their frequency and severity. According to Professor S. Abhilash from Cochin University, climate change intensifies the water cycle by increasing ocean water evaporation due to higher atmospheric temperatures. This leads to the formation of more rain clouds, which in turn, result in heavier downpours during events like monsoons or depressions.
However, climate change is not the only driver behind urban flooding. Urbanization, especially when unplanned, plays a significant role. In many cities, poor land-use planning and inadequate management of natural water flows and drainage systems are prevalent. Effective drainage systems are crucial for directing water away from urban areas to natural ‘sinks’ such as seas or reservoirs. Yet, these systems can become overwhelmed, and when combined with phenomena like high tides, urban areas are left prone to flooding.
The development of ‘grey areas’—urban zones dominated by roads, buildings, and other impervious surfaces—further aggravates the situation. These surfaces impede the ground’s natural ability to absorb rainwater, creating runoff that strained drainage systems must handle. Conversely, ‘blue areas’ or natural water storage sites, including lakes, streams, and ponds, are vital for absorbing excess rainfall and mitigating flood risks.
Addressing urban flooding requires more than managing heavy rainfall; it necessitates adapting urban environments to accommodate these shifts sustainably. This includes considering the elevation of roads, ensuring adequate drainage capacity, and strategically using land to facilitate natural water flow. These measures are essential for creating resilient urban landscapes capable of withstanding the challenges posed by both climate change and rapid urban development.
Urban Flooding in Kerala: The Critical Role of Planning
In Kerala, urbanization predominantly unfolds along its extensive coastline, an area inherently prone to urban flooding due to a combination of geographic and environmental factors. The region’s vulnerability is amplified by natural upstream runoff, seasonal sea turbulence, and a high groundwater table, all contributing significantly to the state’s susceptibility to flooding.
Unlike the east coast of India, which has frequently confronted cyclones and low-pressure systems and thus integrated robust flood management systems into urban planning, the west coast, including Kerala, has historically perceived such events as rare. This perception has led to a less rigorous incorporation of flood management strategies in urban development, an oversight starkly highlighted during events like the catastrophic flooding in Mumbai on July 25, 2005, when a day’s intense rainfall caused extended urban turmoil.
The primary concern here is not merely the extent of urban development but the lack of adequate flood risk consideration within urban planning—a gap that climate change is rendering increasingly critical. The unpredictable nature of climate change, with its varied impacts and manifestations, points to the insufficiency of traditional urban planning approaches.
In Kerala, although there are advanced drainage systems that combine natural channels with man-made infrastructure, the functionality of these systems has shifted over time. Originally also designed to manage floods, many of these drainage systems have been repurposed to handle wastewater and solid waste, significantly diminishing their capacity to manage flood situations effectively.
Sponge City: A Resilient Urban Planning Strategy for Kerala
The monsoon season in Kerala brings robust westerly winds that drive the Indian Ocean eastward, elevating sea levels along the coast. Combined with heavy rainfall and turbulent seas, these conditions challenge even the most well-constructed drainage systems, often leading to severe flooding. In response, urban planners are increasingly considering the “Sponge City” concept, an innovative approach designed to mitigate such issues.
A Sponge City aims to absorb and capture rainwater, allowing for its slow release or reuse, rather than letting it contribute to flooding. This strategy is particularly crucial in managing the balance between urban landscapes’ grey areas and blue areas. The primary objective is twofold: to alleviate flooding and to combat water scarcity by storing excess rainwater for future use.
In Kerala, where climate change effects manifest as both excessive rainfall and periodic droughts, the relevance of the Sponge City concept is particularly pronounced. Historically, the coastal cities of Kerala naturally functioned as sponge cities, with extensive blue areas consisting of water bodies and fields. However, rapid and often uncontrolled urbanization has significantly diminished these crucial blue areas.
Sponge City: A Resilient Urban Planning Strategy for Kerala
In Kerala, a state abundant with wetlands, the challenges of urbanization and its impact on these crucial ecosystems are significant. Wetlands in Kerala—including paddy fields, mangroves, ponds, and streams—have undergone extensive filling both legally and illegally over the past few decades. This transformation has been driven not only by private interests but also for public projects, reflecting complex societal needs and values. Urbanization, often viewed as a societal advancement reflecting collective aspirations, also brings with it governance challenges that affect these natural resources.
The responsibility for managing and protecting wetlands cannot be ascribed solely to one entity; it is a shared duty that involves various levels of governance, including the government, local authorities, public departments, and the citizenry, along with market forces. This complex governance ecosystem must balance private and public interests, which often intersect and sometimes conflict, particularly in the use of natural resources like wetlands.
Private encroachments on water bodies often arise from basic human needs, such as housing, as seen in the Life Houses in Kuttanad, which are constructed on reclaimed land. These are not just expressions of private luxury but also reflect a public interest in providing social equality and housing. Similarly, public encroachments, such as those for infrastructure like roads, are responses to increasing population density and the need for enhanced transportation networks in urban areas. These developments, while necessary, tend to encroach upon and often degrade water bodies and drainage systems.
In essence, both individual actions and regulatory frameworks share the responsibility for managing the impacts of urbanization on wetlands. It is crucial for governance systems to evolve and address these complexities by improving regulatory measures and encouraging responsible behavior among all stakeholders. Addressing these challenges is not just about enforcing regulations but also about fostering a collective responsibility that aligns with both the immediate needs and long-term sustainability goals of society.
